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-rw-r--r--fs/crypto/Kconfig2
-rw-r--r--fs/crypto/Makefile10
-rw-r--r--fs/crypto/crypto.c45
-rw-r--r--fs/crypto/fname.c47
-rw-r--r--fs/crypto/fscrypt_private.h399
-rw-r--r--fs/crypto/hkdf.c181
-rw-r--r--fs/crypto/hooks.c6
-rw-r--r--fs/crypto/keyinfo.c611
-rw-r--r--fs/crypto/keyring.c984
-rw-r--r--fs/crypto/keysetup.c591
-rw-r--r--fs/crypto/keysetup_v1.c340
-rw-r--r--fs/crypto/policy.c434
-rw-r--r--fs/ext4/ioctl.c32
-rw-r--r--fs/ext4/super.c3
-rw-r--r--fs/f2fs/file.c58
-rw-r--r--fs/f2fs/super.c2
-rw-r--r--fs/super.c2
-rw-r--r--fs/ubifs/ioctl.c20
-rw-r--r--fs/ubifs/super.c11
19 files changed, 2961 insertions, 817 deletions
diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig
index 5fdf24877c17..ff5a1746cbae 100644
--- a/fs/crypto/Kconfig
+++ b/fs/crypto/Kconfig
@@ -7,6 +7,8 @@ config FS_ENCRYPTION
select CRYPTO_ECB
select CRYPTO_XTS
select CRYPTO_CTS
+ select CRYPTO_SHA512
+ select CRYPTO_HMAC
select KEYS
help
Enable encryption of files and directories. This
diff --git a/fs/crypto/Makefile b/fs/crypto/Makefile
index 4f0df5e682e4..232e2bb5a337 100644
--- a/fs/crypto/Makefile
+++ b/fs/crypto/Makefile
@@ -1,5 +1,13 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_FS_ENCRYPTION) += fscrypto.o
-fscrypto-y := crypto.o fname.o hooks.o keyinfo.o policy.o
+fscrypto-y := crypto.o \
+ fname.o \
+ hkdf.o \
+ hooks.o \
+ keyring.o \
+ keysetup.o \
+ keysetup_v1.o \
+ policy.o
+
fscrypto-$(CONFIG_BLOCK) += bio.o
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index 45c3d0427fb2..32a7ad0098cc 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -141,7 +141,7 @@ void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num,
memset(iv, 0, ci->ci_mode->ivsize);
iv->lblk_num = cpu_to_le64(lblk_num);
- if (ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY)
+ if (fscrypt_is_direct_key_policy(&ci->ci_policy))
memcpy(iv->nonce, ci->ci_nonce, FS_KEY_DERIVATION_NONCE_SIZE);
if (ci->ci_essiv_tfm != NULL)
@@ -188,10 +188,8 @@ int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw,
res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
skcipher_request_free(req);
if (res) {
- fscrypt_err(inode->i_sb,
- "%scryption failed for inode %lu, block %llu: %d",
- (rw == FS_DECRYPT ? "de" : "en"),
- inode->i_ino, lblk_num, res);
+ fscrypt_err(inode, "%scryption failed for block %llu: %d",
+ (rw == FS_DECRYPT ? "De" : "En"), lblk_num, res);
return res;
}
return 0;
@@ -453,7 +451,7 @@ fail:
return res;
}
-void fscrypt_msg(struct super_block *sb, const char *level,
+void fscrypt_msg(const struct inode *inode, const char *level,
const char *fmt, ...)
{
static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
@@ -467,8 +465,9 @@ void fscrypt_msg(struct super_block *sb, const char *level,
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
- if (sb)
- printk("%sfscrypt (%s): %pV\n", level, sb->s_id, &vaf);
+ if (inode)
+ printk("%sfscrypt (%s, inode %lu): %pV\n",
+ level, inode->i_sb->s_id, inode->i_ino, &vaf);
else
printk("%sfscrypt: %pV\n", level, &vaf);
va_end(args);
@@ -479,6 +478,8 @@ void fscrypt_msg(struct super_block *sb, const char *level,
*/
static int __init fscrypt_init(void)
{
+ int err = -ENOMEM;
+
/*
* Use an unbound workqueue to allow bios to be decrypted in parallel
* even when they happen to complete on the same CPU. This sacrifices
@@ -501,31 +502,19 @@ static int __init fscrypt_init(void)
if (!fscrypt_info_cachep)
goto fail_free_ctx;
+ err = fscrypt_init_keyring();
+ if (err)
+ goto fail_free_info;
+
return 0;
+fail_free_info:
+ kmem_cache_destroy(fscrypt_info_cachep);
fail_free_ctx:
kmem_cache_destroy(fscrypt_ctx_cachep);
fail_free_queue:
destroy_workqueue(fscrypt_read_workqueue);
fail:
- return -ENOMEM;
-}
-module_init(fscrypt_init)
-
-/**
- * fscrypt_exit() - Shutdown the fs encryption system
- */
-static void __exit fscrypt_exit(void)
-{
- fscrypt_destroy();
-
- if (fscrypt_read_workqueue)
- destroy_workqueue(fscrypt_read_workqueue);
- kmem_cache_destroy(fscrypt_ctx_cachep);
- kmem_cache_destroy(fscrypt_info_cachep);
-
- fscrypt_essiv_cleanup();
+ return err;
}
-module_exit(fscrypt_exit);
-
-MODULE_LICENSE("GPL");
+late_initcall(fscrypt_init)
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 00d150ff3033..3da3707c10e3 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -71,9 +71,7 @@ int fname_encrypt(struct inode *inode, const struct qstr *iname,
res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
skcipher_request_free(req);
if (res < 0) {
- fscrypt_err(inode->i_sb,
- "Filename encryption failed for inode %lu: %d",
- inode->i_ino, res);
+ fscrypt_err(inode, "Filename encryption failed: %d", res);
return res;
}
@@ -117,9 +115,7 @@ static int fname_decrypt(struct inode *inode,
res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait);
skcipher_request_free(req);
if (res < 0) {
- fscrypt_err(inode->i_sb,
- "Filename decryption failed for inode %lu: %d",
- inode->i_ino, res);
+ fscrypt_err(inode, "Filename decryption failed: %d", res);
return res;
}
@@ -127,44 +123,45 @@ static int fname_decrypt(struct inode *inode,
return 0;
}
-static const char *lookup_table =
+static const char lookup_table[65] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
#define BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3)
/**
- * digest_encode() -
+ * base64_encode() -
*
- * Encodes the input digest using characters from the set [a-zA-Z0-9_+].
+ * Encodes the input string using characters from the set [A-Za-z0-9+,].
* The encoded string is roughly 4/3 times the size of the input string.
+ *
+ * Return: length of the encoded string
*/
-static int digest_encode(const char *src, int len, char *dst)
+static int base64_encode(const u8 *src, int len, char *dst)
{
- int i = 0, bits = 0, ac = 0;
+ int i, bits = 0, ac = 0;
char *cp = dst;
- while (i < len) {
- ac += (((unsigned char) src[i]) << bits);
+ for (i = 0; i < len; i++) {
+ ac += src[i] << bits;
bits += 8;
do {
*cp++ = lookup_table[ac & 0x3f];
ac >>= 6;
bits -= 6;
} while (bits >= 6);
- i++;
}
if (bits)
*cp++ = lookup_table[ac & 0x3f];
return cp - dst;
}
-static int digest_decode(const char *src, int len, char *dst)
+static int base64_decode(const char *src, int len, u8 *dst)
{
- int i = 0, bits = 0, ac = 0;
+ int i, bits = 0, ac = 0;
const char *p;
- char *cp = dst;
+ u8 *cp = dst;
- while (i < len) {
+ for (i = 0; i < len; i++) {
p = strchr(lookup_table, src[i]);
if (p == NULL || src[i] == 0)
return -2;
@@ -175,7 +172,6 @@ static int digest_decode(const char *src, int len, char *dst)
ac >>= 8;
bits -= 8;
}
- i++;
}
if (ac)
return -1;
@@ -185,8 +181,9 @@ static int digest_decode(const char *src, int len, char *dst)
bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
u32 max_len, u32 *encrypted_len_ret)
{
- int padding = 4 << (inode->i_crypt_info->ci_flags &
- FS_POLICY_FLAGS_PAD_MASK);
+ const struct fscrypt_info *ci = inode->i_crypt_info;
+ int padding = 4 << (fscrypt_policy_flags(&ci->ci_policy) &
+ FSCRYPT_POLICY_FLAGS_PAD_MASK);
u32 encrypted_len;
if (orig_len > max_len)
@@ -272,7 +269,7 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
return fname_decrypt(inode, iname, oname);
if (iname->len <= FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE) {
- oname->len = digest_encode(iname->name, iname->len,
+ oname->len = base64_encode(iname->name, iname->len,
oname->name);
return 0;
}
@@ -287,7 +284,7 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
FSCRYPT_FNAME_DIGEST(iname->name, iname->len),
FSCRYPT_FNAME_DIGEST_SIZE);
oname->name[0] = '_';
- oname->len = 1 + digest_encode((const char *)&digested_name,
+ oname->len = 1 + base64_encode((const u8 *)&digested_name,
sizeof(digested_name), oname->name + 1);
return 0;
}
@@ -380,8 +377,8 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
if (fname->crypto_buf.name == NULL)
return -ENOMEM;
- ret = digest_decode(iname->name + digested, iname->len - digested,
- fname->crypto_buf.name);
+ ret = base64_decode(iname->name + digested, iname->len - digested,
+ fname->crypto_buf.name);
if (ret < 0) {
ret = -ENOENT;
goto errout;
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 8978eec9d766..e84efc01512e 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -4,9 +4,8 @@
*
* Copyright (C) 2015, Google, Inc.
*
- * This contains encryption key functions.
- *
- * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
+ * Originally written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar.
+ * Heavily modified since then.
*/
#ifndef _FSCRYPT_PRIVATE_H
@@ -15,30 +14,133 @@
#include <linux/fscrypt.h>
#include <crypto/hash.h>
-/* Encryption parameters */
+#define CONST_STRLEN(str) (sizeof(str) - 1)
+
#define FS_KEY_DERIVATION_NONCE_SIZE 16
-/**
- * Encryption context for inode
- *
- * Protector format:
- * 1 byte: Protector format (1 = this version)
- * 1 byte: File contents encryption mode
- * 1 byte: File names encryption mode
- * 1 byte: Flags
- * 8 bytes: Master Key descriptor
- * 16 bytes: Encryption Key derivation nonce
- */
-struct fscrypt_context {
- u8 format;
+#define FSCRYPT_MIN_KEY_SIZE 16
+
+#define FSCRYPT_CONTEXT_V1 1
+#define FSCRYPT_CONTEXT_V2 2
+
+struct fscrypt_context_v1 {
+ u8 version; /* FSCRYPT_CONTEXT_V1 */
u8 contents_encryption_mode;
u8 filenames_encryption_mode;
u8 flags;
- u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
+ u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
-} __packed;
+};
-#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1
+struct fscrypt_context_v2 {
+ u8 version; /* FSCRYPT_CONTEXT_V2 */
+ u8 contents_encryption_mode;
+ u8 filenames_encryption_mode;
+ u8 flags;
+ u8 __reserved[4];
+ u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
+ u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+};
+
+/**
+ * fscrypt_context - the encryption context of an inode
+ *
+ * This is the on-disk equivalent of an fscrypt_policy, stored alongside each
+ * encrypted file usually in a hidden extended attribute. It contains the
+ * fields from the fscrypt_policy, in order to identify the encryption algorithm
+ * and key with which the file is encrypted. It also contains a nonce that was
+ * randomly generated by fscrypt itself; this is used as KDF input or as a tweak
+ * to cause different files to be encrypted differently.
+ */
+union fscrypt_context {
+ u8 version;
+ struct fscrypt_context_v1 v1;
+ struct fscrypt_context_v2 v2;
+};
+
+/*
+ * Return the size expected for the given fscrypt_context based on its version
+ * number, or 0 if the context version is unrecognized.
+ */
+static inline int fscrypt_context_size(const union fscrypt_context *ctx)
+{
+ switch (ctx->version) {
+ case FSCRYPT_CONTEXT_V1:
+ BUILD_BUG_ON(sizeof(ctx->v1) != 28);
+ return sizeof(ctx->v1);
+ case FSCRYPT_CONTEXT_V2:
+ BUILD_BUG_ON(sizeof(ctx->v2) != 40);
+ return sizeof(ctx->v2);
+ }
+ return 0;
+}
+
+#undef fscrypt_policy
+union fscrypt_policy {
+ u8 version;
+ struct fscrypt_policy_v1 v1;
+ struct fscrypt_policy_v2 v2;
+};
+
+/*
+ * Return the size expected for the given fscrypt_policy based on its version
+ * number, or 0 if the policy version is unrecognized.
+ */
+static inline int fscrypt_policy_size(const union fscrypt_policy *policy)
+{
+ switch (policy->version) {
+ case FSCRYPT_POLICY_V1:
+ return sizeof(policy->v1);
+ case FSCRYPT_POLICY_V2:
+ return sizeof(policy->v2);
+ }
+ return 0;
+}
+
+/* Return the contents encryption mode of a valid encryption policy */
+static inline u8
+fscrypt_policy_contents_mode(const union fscrypt_policy *policy)
+{
+ switch (policy->version) {
+ case FSCRYPT_POLICY_V1:
+ return policy->v1.contents_encryption_mode;
+ case FSCRYPT_POLICY_V2:
+ return policy->v2.contents_encryption_mode;
+ }
+ BUG();
+}
+
+/* Return the filenames encryption mode of a valid encryption policy */
+static inline u8
+fscrypt_policy_fnames_mode(const union fscrypt_policy *policy)
+{
+ switch (policy->version) {
+ case FSCRYPT_POLICY_V1:
+ return policy->v1.filenames_encryption_mode;
+ case FSCRYPT_POLICY_V2:
+ return policy->v2.filenames_encryption_mode;
+ }
+ BUG();
+}
+
+/* Return the flags (FSCRYPT_POLICY_FLAG*) of a valid encryption policy */
+static inline u8
+fscrypt_policy_flags(const union fscrypt_policy *policy)
+{
+ switch (policy->version) {
+ case FSCRYPT_POLICY_V1:
+ return policy->v1.flags;
+ case FSCRYPT_POLICY_V2:
+ return policy->v2.flags;
+ }
+ BUG();
+}
+
+static inline bool
+fscrypt_is_direct_key_policy(const union fscrypt_policy *policy)
+{
+ return fscrypt_policy_flags(policy) & FSCRYPT_POLICY_FLAG_DIRECT_KEY;
+}
/**
* For encrypted symlinks, the ciphertext length is stored at the beginning
@@ -68,23 +170,37 @@ struct fscrypt_info {
struct crypto_cipher *ci_essiv_tfm;
/*
- * Encryption mode used for this inode. It corresponds to either
- * ci_data_mode or ci_filename_mode, depending on the inode type.
+ * Encryption mode used for this inode. It corresponds to either the
+ * contents or filenames encryption mode, depending on the inode type.
*/
struct fscrypt_mode *ci_mode;
+ /* Back-pointer to the inode */
+ struct inode *ci_inode;
+
+ /*
+ * The master key with which this inode was unlocked (decrypted). This
+ * will be NULL if the master key was found in a process-subscribed
+ * keyring rather than in the filesystem-level keyring.
+ */
+ struct key *ci_master_key;
+
+ /*
+ * Link in list of inodes that were unlocked with the master key.
+ * Only used when ->ci_master_key is set.
+ */
+ struct list_head ci_master_key_link;
+
/*
- * If non-NULL, then this inode uses a master key directly rather than a
- * derived key, and ci_ctfm will equal ci_master_key->mk_ctfm.
- * Otherwise, this inode uses a derived key.
+ * If non-NULL, then encryption is done using the master key directly
+ * and ci_ctfm will equal ci_direct_key->dk_ctfm.
*/
- struct fscrypt_master_key *ci_master_key;
+ struct fscrypt_direct_key *ci_direct_key;
- /* fields from the fscrypt_context */
- u8 ci_data_mode;
- u8 ci_filename_mode;
- u8 ci_flags;
- u8 ci_master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
+ /* The encryption policy used by this inode */
+ union fscrypt_policy ci_policy;
+
+ /* This inode's nonce, copied from the fscrypt_context */
u8 ci_nonce[FS_KEY_DERIVATION_NONCE_SIZE];
};
@@ -98,16 +214,16 @@ typedef enum {
static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
u32 filenames_mode)
{
- if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC &&
- filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS)
+ if (contents_mode == FSCRYPT_MODE_AES_128_CBC &&
+ filenames_mode == FSCRYPT_MODE_AES_128_CTS)
return true;
- if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS &&
- filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS)
+ if (contents_mode == FSCRYPT_MODE_AES_256_XTS &&
+ filenames_mode == FSCRYPT_MODE_AES_256_CTS)
return true;
- if (contents_mode == FS_ENCRYPTION_MODE_ADIANTUM &&
- filenames_mode == FS_ENCRYPTION_MODE_ADIANTUM)
+ if (contents_mode == FSCRYPT_MODE_ADIANTUM &&
+ filenames_mode == FSCRYPT_MODE_ADIANTUM)
return true;
return false;
@@ -125,12 +241,12 @@ extern struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags);
extern const struct dentry_operations fscrypt_d_ops;
extern void __printf(3, 4) __cold
-fscrypt_msg(struct super_block *sb, const char *level, const char *fmt, ...);
+fscrypt_msg(const struct inode *inode, const char *level, const char *fmt, ...);
-#define fscrypt_warn(sb, fmt, ...) \
- fscrypt_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__)
-#define fscrypt_err(sb, fmt, ...) \
- fscrypt_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__)
+#define fscrypt_warn(inode, fmt, ...) \
+ fscrypt_msg((inode), KERN_WARNING, fmt, ##__VA_ARGS__)
+#define fscrypt_err(inode, fmt, ...) \
+ fscrypt_msg((inode), KERN_ERR, fmt, ##__VA_ARGS__)
#define FSCRYPT_MAX_IV_SIZE 32
@@ -155,7 +271,172 @@ extern bool fscrypt_fname_encrypted_size(const struct inode *inode,
u32 orig_len, u32 max_len,
u32 *encrypted_len_ret);
-/* keyinfo.c */
+/* hkdf.c */
+
+struct fscrypt_hkdf {
+ struct crypto_shash *hmac_tfm;
+};
+
+extern int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key,
+ unsigned int master_key_size);
+
+/*
+ * The list of contexts in which fscrypt uses HKDF. These values are used as
+ * the first byte of the HKDF application-specific info string to guarantee that
+ * info strings are never repeated between contexts. This ensures that all HKDF
+ * outputs are unique and cryptographically isolated, i.e. knowledge of one
+ * output doesn't reveal another.
+ */
+#define HKDF_CONTEXT_KEY_IDENTIFIER 1
+#define HKDF_CONTEXT_PER_FILE_KEY 2
+#define HKDF_CONTEXT_PER_MODE_KEY 3
+
+extern int fscrypt_hkdf_expand(struct fscrypt_hkdf *hkdf, u8 context,
+ const u8 *info, unsigned int infolen,
+ u8 *okm, unsigned int okmlen);
+
+extern void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf);
+
+/* keyring.c */
+
+/*
+ * fscrypt_master_key_secret - secret key material of an in-use master key
+ */
+struct fscrypt_master_key_secret {
+
+ /*
+ * For v2 policy keys: HKDF context keyed by this master key.
+ * For v1 policy keys: not set (hkdf.hmac_tfm == NULL).
+ */
+ struct fscrypt_hkdf hkdf;
+
+ /* Size of the raw key in bytes. Set even if ->raw isn't set. */
+ u32 size;
+
+ /* For v1 policy keys: the raw key. Wiped for v2 policy keys. */
+ u8 raw[FSCRYPT_MAX_KEY_SIZE];
+
+} __randomize_layout;
+
+/*
+ * fscrypt_master_key - an in-use master key
+ *
+ * This represents a master encryption key which has been added to the
+ * filesystem and can be used to "unlock" the encrypted files which were
+ * encrypted with it.
+ */
+struct fscrypt_master_key {
+
+ /*
+ * The secret key material. After FS_IOC_REMOVE_ENCRYPTION_KEY is
+ * executed, this is wiped and no new inodes can be unlocked with this
+ * key; however, there may still be inodes in ->mk_decrypted_inodes
+ * which could not be evicted. As long as some inodes still remain,
+ * FS_IOC_REMOVE_ENCRYPTION_KEY can be retried, or
+ * FS_IOC_ADD_ENCRYPTION_KEY can add the secret again.
+ *
+ * Locking: protected by key->sem (outer) and mk_secret_sem (inner).
+ * The reason for two locks is that key->sem also protects modifying
+ * mk_users, which ranks it above the semaphore for the keyring key
+ * type, which is in turn above page faults (via keyring_read). But
+ * sometimes filesystems call fscrypt_get_encryption_info() from within
+ * a transaction, which ranks it below page faults. So we need a
+ * separate lock which protects mk_secret but not also mk_users.
+ */
+ struct fscrypt_master_key_secret mk_secret;
+ struct rw_semaphore mk_secret_sem;
+
+ /*
+ * For v1 policy keys: an arbitrary key descriptor which was assigned by
+ * userspace (->descriptor).
+ *
+ * For v2 policy keys: a cryptographic hash of this key (->identifier).
+ */
+ struct fscrypt_key_specifier mk_spec;
+
+ /*
+ * Keyring which contains a key of type 'key_type_fscrypt_user' for each
+ * user who has added this key. Normally each key will be added by just
+ * one user, but it's possible that multiple users share a key, and in
+ * that case we need to keep track of those users so that one user can't
+ * remove the key before the others want it removed too.
+ *
+ * This is NULL for v1 policy keys; those can only be added by root.
+ *
+ * Locking: in addition to this keyrings own semaphore, this is
+ * protected by the master key's key->sem, so we can do atomic
+ * search+insert. It can also be searched without taking any locks, but
+ * in that case the returned key may have already been removed.
+ */
+ struct key *mk_users;
+
+ /*
+ * Length of ->mk_decrypted_inodes, plus one if mk_secret is present.
+ * Once this goes to 0, the master key is removed from ->s_master_keys.
+ * The 'struct fscrypt_master_key' will continue to live as long as the
+ * 'struct key' whose payload it is, but we won't let this reference
+ * count rise again.
+ */
+ refcount_t mk_refcount;
+
+ /*
+ * List of inodes that were unlocked using this key. This allows the
+ * inodes to be evicted efficiently if the key is removed.
+ */
+ struct list_head mk_decrypted_inodes;
+ spinlock_t mk_decrypted_inodes_lock;
+
+ /* Per-mode tfms for DIRECT_KEY policies, allocated on-demand */
+ struct crypto_skcipher *mk_mode_keys[__FSCRYPT_MODE_MAX + 1];
+
+} __randomize_layout;
+
+static inline bool
+is_master_key_secret_present(const struct fscrypt_master_key_secret *secret)
+{
+ /*
+ * The READ_ONCE() is only necessary for fscrypt_drop_inode() and
+ * fscrypt_key_describe(). These run in atomic context, so they can't
+ * take ->mk_secret_sem and thus 'secret' can change concurrently which
+ * would be a data race. But they only need to know whether the secret
+ * *was* present at the time of check, so READ_ONCE() suffices.
+ */
+ return READ_ONCE(secret->size) != 0;
+}
+
+static inline const char *master_key_spec_type(
+ const struct fscrypt_key_specifier *spec)
+{
+ switch (spec->type) {
+ case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR:
+ return "descriptor";
+ case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER:
+ return "identifier";
+ }
+ return "[unknown]";
+}
+
+static inline int master_key_spec_len(const struct fscrypt_key_specifier *spec)
+{
+ switch (spec->type) {
+ case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR:
+ return FSCRYPT_KEY_DESCRIPTOR_SIZE;
+ case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER:
+ return FSCRYPT_KEY_IDENTIFIER_SIZE;
+ }
+ return 0;
+}
+
+extern struct key *
+fscrypt_find_master_key(struct super_block *sb,
+ const struct fscrypt_key_specifier *mk_spec);
+
+extern int fscrypt_verify_key_added(struct super_block *sb,
+ const u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]);
+
+extern int __init fscrypt_init_keyring(void);
+
+/* keysetup.c */
struct fscrypt_mode {
const char *friendly_name;
@@ -166,6 +447,36 @@ struct fscrypt_mode {
bool needs_essiv;
};
-extern void __exit fscrypt_essiv_cleanup(void);
+static inline bool
+fscrypt_mode_supports_direct_key(const struct fscrypt_mode *mode)
+{
+ return mode->ivsize >= offsetofend(union fscrypt_iv, nonce);
+}
+
+extern struct crypto_skcipher *
+fscrypt_allocate_skcipher(struct fscrypt_mode *mode, const u8 *raw_key,
+ const struct inode *inode);
+
+extern int fscrypt_set_derived_key(struct fscrypt_info *ci,
+ const u8 *derived_key);
+
+/* keysetup_v1.c */
+
+extern void fscrypt_put_direct_key(struct fscrypt_direct_key *dk);
+
+extern int fscrypt_setup_v1_file_key(struct fscrypt_info *ci,
+ const u8 *raw_master_key);
+
+extern int fscrypt_setup_v1_file_key_via_subscribed_keyrings(
+ struct fscrypt_info *ci);
+/* policy.c */
+
+extern bool fscrypt_policies_equal(const union fscrypt_policy *policy1,
+ const union fscrypt_policy *policy2);
+extern bool fscrypt_supported_policy(const union fscrypt_policy *policy_u,
+ const struct inode *inode);
+extern int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
+ const union fscrypt_context *ctx_u,
+ int ctx_size);
#endif /* _FSCRYPT_PRIVATE_H */
diff --git a/fs/crypto/hkdf.c b/fs/crypto/hkdf.c
new file mode 100644
index 000000000000..f21873e1b467
--- /dev/null
+++ b/fs/crypto/hkdf.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Implementation of HKDF ("HMAC-based Extract-and-Expand Key Derivation
+ * Function"), aka RFC 5869. See also the original paper (Krawczyk 2010):
+ * "Cryptographic Extraction and Key Derivation: The HKDF Scheme".
+ *
+ * This is used to derive keys from the fscrypt master keys.
+ *
+ * Copyright 2019 Google LLC
+ */
+
+#include <crypto/hash.h>
+#include <crypto/sha.h>
+
+#include "fscrypt_private.h"
+
+/*
+ * HKDF supports any unkeyed cryptographic hash algorithm, but fscrypt uses
+ * SHA-512 because it is reasonably secure and efficient; and since it produces
+ * a 64-byte digest, deriving an AES-256-XTS key preserves all 64 bytes of
+ * entropy from the master key and requires only one iteration of HKDF-Expand.
+ */
+#define HKDF_HMAC_ALG "hmac(sha512)"
+#define HKDF_HASHLEN SHA512_DIGEST_SIZE
+
+/*
+ * HKDF consists of two steps:
+ *
+ * 1. HKDF-Extract: extract a pseudorandom key of length HKDF_HASHLEN bytes from
+ * the input keying material and optional salt.
+ * 2. HKDF-Expand: expand the pseudorandom key into output keying material of
+ * any length, parameterized by an application-specific info string.
+ *
+ * HKDF-Extract can be skipped if the input is already a pseudorandom key of
+ * length HKDF_HASHLEN bytes. However, cipher modes other than AES-256-XTS take
+ * shorter keys, and we don't want to force users of those modes to provide
+ * unnecessarily long master keys. Thus fscrypt still does HKDF-Extract. No
+ * salt is used, since fscrypt master keys should already be pseudorandom and
+ * there's no way to persist a random salt per master key from kernel mode.
+ */
+
+/* HKDF-Extract (RFC 5869 section 2.2), unsalted */
+static int hkdf_extract(struct crypto_shash *hmac_tfm, const u8 *ikm,
+ unsigned int ikmlen, u8 prk[HKDF_HASHLEN])
+{
+ static const u8 default_salt[HKDF_HASHLEN];
+ SHASH_DESC_ON_STACK(desc, hmac_tfm);
+ int err;
+
+ err = crypto_shash_setkey(hmac_tfm, default_salt, HKDF_HASHLEN);
+ if (err)
+ return err;
+
+ desc->tfm = hmac_tfm;
+ err = crypto_shash_digest(desc, ikm, ikmlen, prk);
+ shash_desc_zero(desc);
+ return err;
+}
+
+/*
+ * Compute HKDF-Extract using the given master key as the input keying material,
+ * and prepare an HMAC transform object keyed by the resulting pseudorandom key.
+ *
+ * Afterwards, the keyed HMAC transform object can be used for HKDF-Expand many
+ * times without having to recompute HKDF-Extract each time.
+ */
+int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key,
+ unsigned int master_key_size)
+{
+ struct crypto_shash *hmac_tfm;
+ u8 prk[HKDF_HASHLEN];
+ int err;
+
+ hmac_tfm = crypto_alloc_shash(HKDF_HMAC_ALG, 0, 0);
+ if (IS_ERR(hmac_tfm)) {
+ fscrypt_err(NULL, "Error allocating " HKDF_HMAC_ALG ": %ld",
+ PTR_ERR(hmac_tfm));
+ return PTR_ERR(hmac_tfm);
+ }
+
+ if (WARN_ON(crypto_shash_digestsize(hmac_tfm) != sizeof(prk))) {
+ err = -EINVAL;
+ goto err_free_tfm;
+ }
+
+ err = hkdf_extract(hmac_tfm, master_key, master_key_size, prk);
+ if (err)
+ goto err_free_tfm;
+
+ err = crypto_shash_setkey(hmac_tfm, prk, sizeof(prk));
+ if (err)
+ goto err_free_tfm;
+
+ hkdf->hmac_tfm = hmac_tfm;
+ goto out;
+
+err_free_tfm:
+ crypto_free_shash(hmac_tfm);
+out:
+ memzero_explicit(prk, sizeof(prk));
+ return err;
+}
+
+/*
+ * HKDF-Expand (RFC 5869 section 2.3). This expands the pseudorandom key, which
+ * was already keyed into 'hkdf->hmac_tfm' by fscrypt_init_hkdf(), into 'okmlen'
+ * bytes of output keying material parameterized by the application-specific
+ * 'info' of length 'infolen' bytes, prefixed by "fscrypt\0" and the 'context'
+ * byte. This is thread-safe and may be called by multiple threads in parallel.
+ *
+ * ('context' isn't part of the HKDF specification; it's just a prefix fscrypt
+ * adds to its application-specific info strings to guarantee that it doesn't
+ * accidentally repeat an info string when using HKDF for different purposes.)
+ */
+int fscrypt_hkdf_expand(struct fscrypt_hkdf *hkdf, u8 context,
+ const u8 *info, unsigned int infolen,
+ u8 *okm, unsigned int okmlen)
+{
+ SHASH_DESC_ON_STACK(desc, hkdf->hmac_tfm);
+ u8 prefix[9];
+ unsigned int i;
+ int err;
+ const u8 *prev = NULL;
+ u8 counter = 1;
+ u8 tmp[HKDF_HASHLEN];
+
+ if (WARN_ON(okmlen > 255 * HKDF_HASHLEN))
+ return -EINVAL;
+
+ desc->tfm = hkdf->hmac_tfm;
+
+ memcpy(prefix, "fscrypt\0", 8);
+ prefix[8] = context;
+
+ for (i = 0; i < okmlen; i += HKDF_HASHLEN) {
+
+ err = crypto_shash_init(desc);
+ if (err)
+ goto out;
+
+ if (prev) {
+ err = crypto_shash_update(desc, prev, HKDF_HASHLEN);
+ if (err)
+ goto out;
+ }
+
+ err = crypto_shash_update(desc, prefix, sizeof(prefix));
+ if (err)
+ goto out;
+
+ err = crypto_shash_update(desc, info, infolen);
+ if (err)
+ goto out;
+
+ BUILD_BUG_ON(sizeof(counter) != 1);
+ if (okmlen - i < HKDF_HASHLEN) {
+ err = crypto_shash_finup(desc, &counter, 1, tmp);
+ if (err)
+ goto out;
+ memcpy(&okm[i], tmp, okmlen - i);
+ memzero_explicit(tmp, sizeof(tmp));
+ } else {
+ err = crypto_shash_finup(desc, &counter, 1, &okm[i]);
+ if (err)
+ goto out;
+ }
+ counter++;
+ prev = &okm[i];
+ }
+ err = 0;
+out:
+ if (unlikely(err))
+ memzero_explicit(okm, okmlen); /* so caller doesn't need to */
+ shash_desc_zero(desc);
+ return err;
+}
+
+void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf)
+{
+ crypto_free_shash(hkdf->hmac_tfm);
+}
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
index c1d6715d88e9..bb3b7fcfdd48 100644
--- a/fs/crypto/hooks.c
+++ b/fs/crypto/hooks.c
@@ -39,9 +39,9 @@ int fscrypt_file_open(struct inode *inode, struct file *filp)
dir = dget_parent(file_dentry(filp));
if (IS_ENCRYPTED(d_inode(dir)) &&
!fscrypt_has_permitted_context(d_inode(dir), inode)) {
- fscrypt_warn(inode->i_sb,
- "inconsistent encryption contexts: %lu/%lu",
- d_inode(dir)->i_ino, inode->i_ino);
+ fscrypt_warn(inode,
+ "Inconsistent encryption context (parent directory: %lu)",
+ d_inode(dir)->i_ino);
err = -EPERM;
}
dput(dir);
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
deleted file mode 100644
index 207ebed918c1..000000000000
--- a/fs/crypto/keyinfo.c
+++ /dev/null
@@ -1,611 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * key management facility for FS encryption support.
- *
- * Copyright (C) 2015, Google, Inc.
- *
- * This contains encryption key functions.
- *
- * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
- */
-
-#include <keys/user-type.h>
-#include <linux/hashtable.h>
-#include <linux/scatterlist.h>
-#include <crypto/aes.h>
-#include <crypto/algapi.h>
-#include <crypto/sha.h>
-#include <crypto/skcipher.h>
-#include "fscrypt_private.h"
-
-static struct crypto_shash *essiv_hash_tfm;
-
-/* Table of keys referenced by FS_POLICY_FLAG_DIRECT_KEY policies */
-static DEFINE_HASHTABLE(fscrypt_master_keys, 6); /* 6 bits = 64 buckets */
-static DEFINE_SPINLOCK(fscrypt_master_keys_lock);
-
-/*
- * Key derivation function. This generates the derived key by encrypting the
- * master key with AES-128-ECB using the inode's nonce as the AES key.
- *
- * The master key must be at least as long as the derived key. If the master
- * key is longer, then only the first 'derived_keysize' bytes are used.
- */
-static int derive_key_aes(const u8 *master_key,
- const struct fscrypt_context *ctx,
- u8 *derived_key, unsigned int derived_keysize)
-{
- int res = 0;
- struct skcipher_request *req = NULL;
- DECLARE_CRYPTO_WAIT(wait);
- struct scatterlist src_sg, dst_sg;
- struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
-
- if (IS_ERR(tfm)) {
- res = PTR_ERR(tfm);
- tfm = NULL;
- goto out;
- }
- crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
- req = skcipher_request_alloc(tfm, GFP_NOFS);
- if (!req) {
- res = -ENOMEM;
- goto out;
- }
- skcipher_request_set_callback(req,
- CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
- crypto_req_done, &wait);
- res = crypto_skcipher_setkey(tfm, ctx->nonce, sizeof(ctx->nonce));
- if (res < 0)
- goto out;
-
- sg_init_one(&src_sg, master_key, derived_keysize);
- sg_init_one(&dst_sg, derived_key, derived_keysize);
- skcipher_request_set_crypt(req, &src_sg, &dst_sg, derived_keysize,
- NULL);
- res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
-out:
- skcipher_request_free(req);
- crypto_free_skcipher(tfm);
- return res;
-}
-
-/*
- * Search the current task's subscribed keyrings for a "logon" key with
- * description prefix:descriptor, and if found acquire a read lock on it and
- * return a pointer to its validated payload in *payload_ret.
- */
-static struct key *
-find_and_lock_process_key(const char *prefix,
- const u8 descriptor[FS_KEY_DESCRIPTOR_SIZE],
- unsigned int min_keysize,
- const struct fscrypt_key **payload_ret)
-{
- char *description;
- struct key *key;
- const struct user_key_payload *ukp;
- const struct fscrypt_key *payload;
-
- description = kasprintf(GFP_NOFS, "%s%*phN", prefix,
- FS_KEY_DESCRIPTOR_SIZE, descriptor);
- if (!description)
- return ERR_PTR(-ENOMEM);
-
- key = request_key(&key_type_logon, description, NULL);
- kfree(description);
- if (IS_ERR(key))
- return key;
-
- down_read(&key->sem);
- ukp = user_key_payload_locked(key);
-
- if (!ukp) /* was the key revoked before we acquired its semaphore? */
- goto invalid;
-
- payload = (const struct fscrypt_key *)ukp->data;
-
- if (ukp->datalen != sizeof(struct fscrypt_key) ||
- payload->size < 1 || payload->size > FS_MAX_KEY_SIZE) {
- fscrypt_warn(NULL,
- "key with description '%s' has invalid payload",
- key->description);
- goto invalid;
- }
-
- if (payload->size < min_keysize) {
- fscrypt_warn(NULL,
- "key with description '%s' is too short (got %u bytes, need %u+ bytes)",
- key->description, payload->size, min_keysize);
- goto invalid;
- }
-
- *payload_ret = payload;
- return key;
-
-invalid:
- up_read(&key->sem);
- key_put(key);
- return ERR_PTR(-ENOKEY);
-}
-
-static struct fscrypt_mode available_modes[] = {
- [FS_ENCRYPTION_MODE_AES_256_XTS] = {
- .friendly_name = "AES-256-XTS",
- .cipher_str = "xts(aes)",
- .keysize = 64,
- .ivsize = 16,
- },
- [FS_ENCRYPTION_MODE_AES_256_CTS] = {
- .friendly_name = "AES-256-CTS-CBC",
- .cipher_str = "cts(cbc(aes))",
- .keysize = 32,
- .ivsize = 16,
- },
- [FS_ENCRYPTION_MODE_AES_128_CBC] = {
- .friendly_name = "AES-128-CBC",
- .cipher_str = "cbc(aes)",
- .keysize = 16,
- .ivsize = 16,
- .needs_essiv = true,
- },
- [FS_ENCRYPTION_MODE_AES_128_CTS] = {
- .friendly_name = "AES-128-CTS-CBC",
- .cipher_str = "cts(cbc(aes))",
- .keysize = 16,
- .ivsize = 16,
- },
- [FS_ENCRYPTION_MODE_ADIANTUM] = {
- .friendly_name = "Adiantum",
- .cipher_str = "adiantum(xchacha12,aes)",
- .keysize = 32,
- .ivsize = 32,
- },
-};
-
-static struct fscrypt_mode *
-select_encryption_mode(const struct fscrypt_info *ci, const struct inode *inode)
-{
- if (!fscrypt_valid_enc_modes(ci->ci_data_mode, ci->ci_filename_mode)) {
- fscrypt_warn(inode->i_sb,
- "inode %lu uses unsupported encryption modes (contents mode %d, filenames mode %d)",
- inode->i_ino, ci->ci_data_mode,
- ci->ci_filename_mode);
- return ERR_PTR(-EINVAL);
- }
-
- if (S_ISREG(inode->i_mode))
- return &available_modes[ci->ci_data_mode];
-
- if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
- return &available_modes[ci->ci_filename_mode];
-
- WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n",
- inode->i_ino, (inode->i_mode & S_IFMT));
- return ERR_PTR(-EINVAL);
-}
-
-/* Find the master key, then derive the inode's actual encryption key */
-static int find_and_derive_key(const struct inode *inode,
- const struct fscrypt_context *ctx,
- u8 *derived_key, const struct fscrypt_mode *mode)
-{
- struct key *key;
- const struct fscrypt_key *payload;
- int err;
-
- key = find_and_lock_process_key(FS_KEY_DESC_PREFIX,
- ctx->master_key_descriptor,
- mode->keysize, &payload);
- if (key == ERR_PTR(-ENOKEY) && inode->i_sb->s_cop->key_prefix) {
- key = find_and_lock_process_key(inode->i_sb->s_cop->key_prefix,
- ctx->master_key_descriptor,
- mode->keysize, &payload);
- }
- if (IS_ERR(key))
- return PTR_ERR(key);
-
- if (ctx->flags & FS_POLICY_FLAG_DIRECT_KEY) {
- if (mode->ivsize < offsetofend(union fscrypt_iv, nonce)) {
- fscrypt_warn(inode->i_sb,
- "direct key mode not allowed with %s",
- mode->friendly_name);
- err = -EINVAL;
- } else if (ctx->contents_encryption_mode !=
- ctx->filenames_encryption_mode) {
- fscrypt_warn(inode->i_sb,
- "direct key mode not allowed with different contents and filenames modes");
- err = -EINVAL;
- } else {
- memcpy(derived_key, payload->raw, mode->keysize);
- err = 0;
- }
- } else {
- err = derive_key_aes(payload->raw, ctx, derived_key,
- mode->keysize);
- }
- up_read(&key->sem);
- key_put(key);
- return err;
-}
-
-/* Allocate and key a symmetric cipher object for the given encryption mode */
-static struct crypto_skcipher *
-allocate_skcipher_for_mode(struct fscrypt_mode *mode, const u8 *raw_key,
- const struct inode *inode)
-{
- struct crypto_skcipher *tfm;
- int err;
-
- tfm = crypto_alloc_skcipher(mode->cipher_str, 0, 0);
- if (IS_ERR(tfm)) {
- fscrypt_warn(inode->i_sb,
- "error allocating '%s' transform for inode %lu: %ld",
- mode->cipher_str, inode->i_ino, PTR_ERR(tfm));
- return tfm;
- }
- if (unlikely(!mode->logged_impl_name)) {
- /*
- * fscrypt performance can vary greatly depending on which
- * crypto algorithm implementation is used. Help people debug
- * performance problems by logging the ->cra_driver_name the
- * first time a mode is used. Note that multiple threads can
- * race here, but it doesn't really matter.
- */
- mode->logged_impl_name = true;
- pr_info("fscrypt: %s using implementation \"%s\"\n",
- mode->friendly_name,
- crypto_skcipher_alg(tfm)->base.cra_driver_name);
- }
- crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
- err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize);
- if (err)
- goto err_free_tfm;
-
- return tfm;
-
-err_free_tfm:
- crypto_free_skcipher(tfm);
- return ERR_PTR(err);
-}
-
-/* Master key referenced by FS_POLICY_FLAG_DIRECT_KEY policy */
-struct fscrypt_master_key {
- struct hlist_node mk_node;
- refcount_t mk_refcount;
- const struct fscrypt_mode *mk_mode;
- struct crypto_skcipher *mk_ctfm;
- u8 mk_descriptor[FS_KEY_DESCRIPTOR_SIZE];
- u8 mk_raw[FS_MAX_KEY_SIZE];
-};
-
-static void free_master_key(struct fscrypt_master_key *mk)
-{
- if (mk) {
- crypto_free_skcipher(mk->mk_ctfm);
- kzfree(mk);
- }
-}
-
-static void put_master_key(struct fscrypt_master_key *mk)
-{
- if (!refcount_dec_and_lock(&mk->mk_refcount, &fscrypt_master_keys_lock))
- return;
- hash_del(&mk->mk_node);
- spin_unlock(&fscrypt_master_keys_lock);
-
- free_master_key(mk);
-}
-
-/*
- * Find/insert the given master key into the fscrypt_master_keys table. If
- * found, it is returned with elevated refcount, and 'to_insert' is freed if
- * non-NULL. If not found, 'to_insert' is inserted and returned if it's
- * non-NULL; otherwise NULL is returned.
- */
-static struct fscrypt_master_key *
-find_or_insert_master_key(struct fscrypt_master_key *to_insert,
- const u8 *raw_key, const struct fscrypt_mode *mode,
- const struct fscrypt_info *ci)
-{
- unsigned long hash_key;
- struct fscrypt_master_key *mk;
-
- /*
- * Careful: to avoid potentially leaking secret key bytes via timing
- * information, we must key the hash table by descriptor rather than by
- * raw key, and use crypto_memneq() when comparing raw keys.
- */
-
- BUILD_BUG_ON(sizeof(hash_key) > FS_KEY_DESCRIPTOR_SIZE);
- memcpy(&hash_key, ci->ci_master_key_descriptor, sizeof(hash_key));
-
- spin_lock(&fscrypt_master_keys_lock);
- hash_for_each_possible(fscrypt_master_keys, mk, mk_node, hash_key) {
- if (memcmp(ci->ci_master_key_descriptor, mk->mk_descriptor,
- FS_KEY_DESCRIPTOR_SIZE) != 0)
- continue;
- if (mode != mk->mk_mode)
- continue;
- if (crypto_memneq(raw_key, mk->mk_raw, mode->keysize))
- continue;
- /* using existing tfm with same (descriptor, mode, raw_key) */
- refcount_inc(&mk->mk_refcount);
- spin_unlock(&fscrypt_master_keys_lock);
- free_master_key(to_insert);
- return mk;
- }
- if (to_insert)
- hash_add(fscrypt_master_keys, &to_insert->mk_node, hash_key);
- spin_unlock(&fscrypt_master_keys_lock);
- return to_insert;
-}
-
-/* Prepare to encrypt directly using the master key in the given mode */
-static struct fscrypt_master_key *
-fscrypt_get_master_key(const struct fscrypt_info *ci, struct fscrypt_mode *mode,
- const u8 *raw_key, const struct inode *inode)
-{
- struct fscrypt_master_key *mk;
- int err;
-
- /* Is there already a tfm for this key? */
- mk = find_or_insert_master_key(NULL, raw_key, mode, ci);
- if (mk)
- return mk;
-
- /* Nope, allocate one. */
- mk = kzalloc(sizeof(*mk), GFP_NOFS);
- if (!mk)
- return ERR_PTR(-ENOMEM);
- refcount_set(&mk->mk_refcount, 1);
- mk->mk_mode = mode;
- mk->mk_ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
- if (IS_ERR(mk->mk_ctfm)) {
- err = PTR_ERR(mk->mk_ctfm);
- mk->mk_ctfm = NULL;
- goto err_free_mk;
- }
- memcpy(mk->mk_descriptor, ci->ci_master_key_descriptor,
- FS_KEY_DESCRIPTOR_SIZE);
- memcpy(mk->mk_raw, raw_key, mode->keysize);
-
- return find_or_insert_master_key(mk, raw_key, mode, ci);
-
-err_free_mk:
- free_master_key(mk);
- return ERR_PTR(err);
-}
-
-static int derive_essiv_salt(const u8 *key, int keysize, u8 *salt)
-{
- struct crypto_shash *tfm = READ_ONCE(essiv_hash_tfm);
-
- /* init hash transform on demand */
- if (unlikely(!tfm)) {
- struct crypto_shash *prev_tfm;
-
- tfm = crypto_alloc_shash("sha256", 0, 0);
- if (IS_ERR(tfm)) {
- fscrypt_warn(NULL,
- "error allocating SHA-256 transform: %ld",
- PTR_ERR(tfm));
- return PTR_ERR(tfm);
- }
- prev_tfm = cmpxchg(&essiv_hash_tfm, NULL, tfm);
- if (prev_tfm) {
- crypto_free_shash(tfm);
- tfm = prev_tfm;
- }
- }
-
- {
- SHASH_DESC_ON_STACK(desc, tfm);
- desc->tfm = tfm;
-
- return crypto_shash_digest(desc, key, keysize, salt);
- }
-}
-
-static int init_essiv_generator(struct fscrypt_info *ci, const u8 *raw_key,
- int keysize)
-{
- int err;
- struct crypto_cipher *essiv_tfm;
- u8 salt[SHA256_DIGEST_SIZE];
-
- essiv_tfm = crypto_alloc_cipher("aes", 0, 0);
- if (IS_ERR(essiv_tfm))
- return PTR_ERR(essiv_tfm);
-
- ci->ci_essiv_tfm = essiv_tfm;
-
- err = derive_essiv_salt(raw_key, keysize, salt);
- if (err)
- goto out;
-
- /*
- * Using SHA256 to derive the salt/key will result in AES-256 being
- * used for IV generation. File contents encryption will still use the
- * configured keysize (AES-128) nevertheless.
- */
- err = crypto_cipher_setkey(essiv_tfm, salt, sizeof(salt));
- if (err)
- goto out;
-
-out:
- memzero_explicit(salt, sizeof(salt));
- return err;
-}
-
-void __exit fscrypt_essiv_cleanup(void)
-{
- crypto_free_shash(essiv_hash_tfm);
-}
-
-/*
- * Given the encryption mode and key (normally the derived key, but for
- * FS_POLICY_FLAG_DIRECT_KEY mode it's the master key), set up the inode's
- * symmetric cipher transform object(s).
- */
-static int setup_crypto_transform(struct fscrypt_info *ci,
- struct fscrypt_mode *mode,
- const u8 *raw_key, const struct inode *inode)
-{
- struct fscrypt_master_key *mk;
- struct crypto_skcipher *ctfm;
- int err;
-
- if (ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY) {
- mk = fscrypt_get_master_key(ci, mode, raw_key, inode);
- if (IS_ERR(mk))
- return PTR_ERR(mk);
- ctfm = mk->mk_ctfm;
- } else {
- mk = NULL;
- ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
- if (IS_ERR(ctfm))
- return PTR_ERR(ctfm);
- }
- ci->ci_master_key = mk;
- ci->ci_ctfm = ctfm;
-
- if (mode->needs_essiv) {
- /* ESSIV implies 16-byte IVs which implies !DIRECT_KEY */
- WARN_ON(mode->ivsize != AES_BLOCK_SIZE);
- WARN_ON(ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY);
-
- err = init_essiv_generator(ci, raw_key, mode->keysize);
- if (err) {
- fscrypt_warn(inode->i_sb,
- "error initializing ESSIV generator for inode %lu: %d",
- inode->i_ino, err);
- return err;
- }
- }
- return 0;
-}
-
-static void put_crypt_info(struct fscrypt_info *ci)
-{
- if (!ci)
- return;
-
- if (ci->ci_master_key) {
- put_master_key(ci->ci_master_key);
- } else {
- crypto_free_skcipher(ci->ci_ctfm);
- crypto_free_cipher(ci->ci_essiv_tfm);
- }
- kmem_cache_free(fscrypt_info_cachep, ci);
-}
-
-int fscrypt_get_encryption_info(struct inode *inode)
-{
- struct fscrypt_info *crypt_info;
- struct fscrypt_context ctx;
- struct fscrypt_mode *mode;
- u8 *raw_key = NULL;
- int res;
-
- if (fscrypt_has_encryption_key(inode))
- return 0;
-
- res = fscrypt_initialize(inode->i_sb->s_cop->flags);
- if (res)
- return res;
-
- res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
- if (res < 0) {
- if (!fscrypt_dummy_context_enabled(inode) ||
- IS_ENCRYPTED(inode))
- return res;
- /* Fake up a context for an unencrypted directory */
- memset(&ctx, 0, sizeof(ctx));
- ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
- ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
- ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
- memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
- } else if (res != sizeof(ctx)) {
- return -EINVAL;
- }
-
- if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
- return -EINVAL;
-
- if (ctx.flags & ~FS_POLICY_FLAGS_VALID)
- return -EINVAL;
-
- crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_NOFS);
- if (!crypt_info)
- return -ENOMEM;
-
- crypt_info->ci_flags = ctx.flags;
- crypt_info->ci_data_mode = ctx.contents_encryption_mode;
- crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
- memcpy(crypt_info->ci_master_key_descriptor, ctx.master_key_descriptor,
- FS_KEY_DESCRIPTOR_SIZE);
- memcpy(crypt_info->ci_nonce, ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
-
- mode = select_encryption_mode(crypt_info, inode);
- if (IS_ERR(mode)) {
- res = PTR_ERR(mode);
- goto out;
- }
- WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE);
- crypt_info->ci_mode = mode;
-
- /*
- * This cannot be a stack buffer because it may be passed to the
- * scatterlist crypto API as part of key derivation.
- */
- res = -ENOMEM;
- raw_key = kmalloc(mode->keysize, GFP_NOFS);
- if (!raw_key)
- goto out;
-
- res = find_and_derive_key(inode, &ctx, raw_key, mode);
- if (res)
- goto out;
-
- res = setup_crypto_transform(crypt_info, mode, raw_key, inode);
- if (res)
- goto out;
-
- if (cmpxchg_release(&inode->i_crypt_info, NULL, crypt_info) == NULL)
- crypt_info = NULL;
-out:
- if (res == -ENOKEY)
- res = 0;
- put_crypt_info(crypt_info);
- kzfree(raw_key);
- return res;
-}
-EXPORT_SYMBOL(fscrypt_get_encryption_info);
-
-/**
- * fscrypt_put_encryption_info - free most of an inode's fscrypt data
- *
- * Free the inode's fscrypt_info. Filesystems must call this when the inode is
- * being evicted. An RCU grace period need not have elapsed yet.
- */
-void fscrypt_put_encryption_info(struct inode *inode)
-{
- put_crypt_info(inode->i_crypt_info);
- inode->i_crypt_info = NULL;
-}
-EXPORT_SYMBOL(fscrypt_put_encryption_info);
-
-/**
- * fscrypt_free_inode - free an inode's fscrypt data requiring RCU delay
- *
- * Free the inode's cached decrypted symlink target, if any. Filesystems must
- * call this after an RCU grace period, just before they free the inode.
- */
-void fscrypt_free_inode(struct inode *inode)
-{
- if (IS_ENCRYPTED(inode) && S_ISLNK(inode->i_mode)) {
- kfree(inode->i_link);
- inode->i_link = NULL;
- }
-}
-EXPORT_SYMBOL(fscrypt_free_inode);
diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
new file mode 100644
index 000000000000..c34fa7c61b43
--- /dev/null
+++ b/fs/crypto/keyring.c
@@ -0,0 +1,984 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Filesystem-level keyring for fscrypt
+ *
+ * Copyright 2019 Google LLC
+ */
+
+/*
+ * This file implements management of fscrypt master keys in the
+ * filesystem-level keyring, including the ioctls:
+ *
+ * - FS_IOC_ADD_ENCRYPTION_KEY
+ * - FS_IOC_REMOVE_ENCRYPTION_KEY
+ * - FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS
+ * - FS_IOC_GET_ENCRYPTION_KEY_STATUS
+ *
+ * See the "User API" section of Documentation/filesystems/fscrypt.rst for more
+ * information about these ioctls.
+ */
+
+#include <crypto/skcipher.h>
+#include <linux/key-type.h>
+#include <linux/seq_file.h>
+
+#include "fscrypt_private.h"
+
+static void wipe_master_key_secret(struct fscrypt_master_key_secret *secret)
+{
+ fscrypt_destroy_hkdf(&secret->hkdf);
+ memzero_explicit(secret, sizeof(*secret));
+}
+
+static void move_master_key_secret(struct fscrypt_master_key_secret *dst,
+ struct fscrypt_master_key_secret *src)
+{
+ memcpy(dst, src, sizeof(*dst));
+ memzero_explicit(src, sizeof(*src));
+}
+
+static void free_master_key(struct fscrypt_master_key *mk)
+{
+ size_t i;
+
+ wipe_master_key_secret(&mk->mk_secret);
+
+ for (i = 0; i < ARRAY_SIZE(mk->mk_mode_keys); i++)
+ crypto_free_skcipher(mk->mk_mode_keys[i]);
+
+ key_put(mk->mk_users);
+ kzfree(mk);
+}
+
+static inline bool valid_key_spec(const struct fscrypt_key_specifier *spec)
+{
+ if (spec->__reserved)
+ return false;
+ return master_key_spec_len(spec) != 0;
+}
+
+static int fscrypt_key_instantiate(struct key *key,
+ struct key_preparsed_payload *prep)
+{
+ key->payload.data[0] = (struct fscrypt_master_key *)prep->data;
+ return 0;
+}
+
+static void fscrypt_key_destroy(struct key *key)
+{
+ free_master_key(key->payload.data[0]);
+}
+
+static void fscrypt_key_describe(const struct key *key, struct seq_file *m)
+{
+ seq_puts(m, key->description);
+
+ if (key_is_positive(key)) {
+ const struct fscrypt_master_key *mk = key->payload.data[0];
+
+ if (!is_master_key_secret_present(&mk->mk_secret))
+ seq_puts(m, ": secret removed");
+ }
+}
+
+/*
+ * Type of key in ->s_master_keys. Each key of this type represents a master
+ * key which has been added to the filesystem. Its payload is a
+ * 'struct fscrypt_master_key'. The "." prefix in the key type name prevents
+ * users from adding keys of this type via the keyrings syscalls rather than via
+ * the intended method of FS_IOC_ADD_ENCRYPTION_KEY.
+ */
+static struct key_type key_type_fscrypt = {
+ .name = "._fscrypt",
+ .instantiate = fscrypt_key_instantiate,
+ .destroy = fscrypt_key_destroy,
+ .describe = fscrypt_key_describe,
+};
+
+static int fscrypt_user_key_instantiate(struct key *key,
+ struct key_preparsed_payload *prep)
+{
+ /*
+ * We just charge FSCRYPT_MAX_KEY_SIZE bytes to the user's key quota for
+ * each key, regardless of the exact key size. The amount of memory
+ * actually used is greater than the size of the raw key anyway.
+ */
+ return key_payload_reserve(key, FSCRYPT_MAX_KEY_SIZE);
+}
+
+static void fscrypt_user_key_describe(const struct key *key, struct seq_file *m)
+{
+ seq_puts(m, key->description);
+}
+
+/*
+ * Type of key in ->mk_users. Each key of this type represents a particular
+ * user who has added a particular master key.
+ *
+ * Note that the name of this key type really should be something like
+ * ".fscrypt-user" instead of simply ".fscrypt". But the shorter name is chosen
+ * mainly for simplicity of presentation in /proc/keys when read by a non-root
+ * user. And it is expected to be rare that a key is actually added by multiple
+ * users, since users should keep their encryption keys confidential.
+ */
+static struct key_type key_type_fscrypt_user = {
+ .name = ".fscrypt",
+ .instantiate = fscrypt_user_key_instantiate,
+ .describe = fscrypt_user_key_describe,
+};
+
+/* Search ->s_master_keys or ->mk_users */
+static struct key *search_fscrypt_keyring(struct key *keyring,
+ struct key_type *type,
+ const char *description)
+{
+ /*
+ * We need to mark the keyring reference as "possessed" so that we
+ * acquire permission to search it, via the KEY_POS_SEARCH permission.
+ */
+ key_ref_t keyref = make_key_ref(keyring, true /* possessed */);
+
+ keyref = keyring_search(keyref, type, description, false);
+ if (IS_ERR(keyref)) {
+ if (PTR_ERR(keyref) == -EAGAIN || /* not found */
+ PTR_ERR(keyref) == -EKEYREVOKED) /* recently invalidated */
+ keyref = ERR_PTR(-ENOKEY);
+ return ERR_CAST(keyref);
+ }
+ return key_ref_to_ptr(keyref);
+}
+
+#define FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE \
+ (CONST_STRLEN("fscrypt-") + FIELD_SIZEOF(struct super_block, s_id))
+
+#define FSCRYPT_MK_DESCRIPTION_SIZE (2 * FSCRYPT_KEY_IDENTIFIER_SIZE + 1)
+
+#define FSCRYPT_MK_USERS_DESCRIPTION_SIZE \
+ (CONST_STRLEN("fscrypt-") + 2 * FSCRYPT_KEY_IDENTIFIER_SIZE + \
+ CONST_STRLEN("-users") + 1)
+
+#define FSCRYPT_MK_USER_DESCRIPTION_SIZE \
+ (2 * FSCRYPT_KEY_IDENTIFIER_SIZE + CONST_STRLEN(".uid.") + 10 + 1)
+
+static void format_fs_keyring_description(
+ char description[FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE],
+ const struct super_block *sb)
+{
+ sprintf(description, "fscrypt-%s", sb->s_id);
+}
+
+static void format_mk_description(
+ char description[FSCRYPT_MK_DESCRIPTION_SIZE],
+ const struct fscrypt_key_specifier *mk_spec)
+{
+ sprintf(description, "%*phN",
+ master_key_spec_len(mk_spec), (u8 *)&mk_spec->u);
+}
+
+static void format_mk_users_keyring_description(
+ char description[FSCRYPT_MK_USERS_DESCRIPTION_SIZE],
+ const u8 mk_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE])
+{
+ sprintf(description, "fscrypt-%*phN-users",
+ FSCRYPT_KEY_IDENTIFIER_SIZE, mk_identifier);
+}
+
+static void format_mk_user_description(
+ char description[FSCRYPT_MK_USER_DESCRIPTION_SIZE],
+ const u8 mk_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE])
+{
+
+ sprintf(description, "%*phN.uid.%u", FSCRYPT_KEY_IDENTIFIER_SIZE,
+ mk_identifier, __kuid_val(current_fsuid()));
+}
+
+/* Create ->s_master_keys if needed. Synchronized by fscrypt_add_key_mutex. */
+static int allocate_filesystem_keyring(struct super_block *sb)
+{
+ char description[FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE];
+ struct key *keyring;
+
+ if (sb->s_master_keys)
+ return 0;
+
+ format_fs_keyring_description(description, sb);
+ keyring = keyring_alloc(description, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
+ current_cred(), KEY_POS_SEARCH |
+ KEY_USR_SEARCH | KEY_USR_READ | KEY_USR_VIEW,
+ KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
+ if (IS_ERR(keyring))
+ return PTR_ERR(keyring);
+
+ /* Pairs with READ_ONCE() in fscrypt_find_master_key() */
+ smp_store_release(&sb->s_master_keys, keyring);
+ return 0;
+}
+
+void fscrypt_sb_free(struct super_block *sb)
+{
+ key_put(sb->s_master_keys);
+ sb->s_master_keys = NULL;
+}
+
+/*
+ * Find the specified master key in ->s_master_keys.
+ * Returns ERR_PTR(-ENOKEY) if not found.
+ */
+struct key *fscrypt_find_master_key(struct super_block *sb,
+ const struct fscrypt_key_specifier *mk_spec)
+{
+ struct key *keyring;
+ char description[FSCRYPT_MK_DESCRIPTION_SIZE];
+
+ /* pairs with smp_store_release() in allocate_filesystem_keyring() */
+ keyring = READ_ONCE(sb->s_master_keys);
+ if (keyring == NULL)
+ return ERR_PTR(-ENOKEY); /* No keyring yet, so no keys yet. */
+
+ format_mk_description(description, mk_spec);
+ return search_fscrypt_keyring(keyring, &key_type_fscrypt, description);
+}
+
+static int allocate_master_key_users_keyring(struct fscrypt_master_key *mk)
+{
+ char description[FSCRYPT_MK_USERS_DESCRIPTION_SIZE];
+ struct key *keyring;
+
+ format_mk_users_keyring_description(description,
+ mk->mk_spec.u.identifier);
+ keyring = keyring_alloc(description, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
+ current_cred(), KEY_POS_SEARCH |
+ KEY_USR_SEARCH | KEY_USR_READ | KEY_USR_VIEW,
+ KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
+ if (IS_ERR(keyring))
+ return PTR_ERR(keyring);
+
+ mk->mk_users = keyring;
+ return 0;
+}
+
+/*
+ * Find the current user's "key" in the master key's ->mk_users.
+ * Returns ERR_PTR(-ENOKEY) if not found.
+ */
+static struct key *find_master_key_user(struct fscrypt_master_key *mk)
+{
+ char description[FSCRYPT_MK_USER_DESCRIPTION_SIZE];
+
+ format_mk_user_description(description, mk->mk_spec.u.identifier);
+ return search_fscrypt_keyring(mk->mk_users, &key_type_fscrypt_user,
+ description);
+}
+
+/*
+ * Give the current user a "key" in ->mk_users. This charges the user's quota
+ * and marks the master key as added by the current user, so that it cannot be
+ * removed by another user with the key. Either the master key's key->sem must
+ * be held for write, or the master key must be still undergoing initialization.
+ */
+static int add_master_key_user(struct fscrypt_master_key *mk)
+{
+ char description[FSCRYPT_MK_USER_DESCRIPTION_SIZE];
+ struct key *mk_user;
+ int err;
+
+ format_mk_user_description(description, mk->mk_spec.u.identifier);
+ mk_user = key_alloc(&key_type_fscrypt_user, description,
+ current_fsuid(), current_gid(), current_cred(),
+ KEY_POS_SEARCH | KEY_USR_VIEW, 0, NULL);
+ if (IS_ERR(mk_user))
+ return PTR_ERR(mk_user);
+
+ err = key_instantiate_and_link(mk_user, NULL, 0, mk->mk_users, NULL);
+ key_put(mk_user);
+ return err;
+}
+
+/*
+ * Remove the current user's "key" from ->mk_users.
+ * The master key's key->sem must be held for write.
+ *
+ * Returns 0 if removed, -ENOKEY if not found, or another -errno code.
+ */
+static int remove_master_key_user(struct fscrypt_master_key *mk)
+{
+ struct key *mk_user;
+ int err;
+
+ mk_user = find_master_key_user(mk);
+ if (IS_ERR(mk_user))
+ return PTR_ERR(mk_user);
+ err = key_unlink(mk->mk_users, mk_user);
+ key_put(mk_user);
+ return err;
+}
+
+/*
+ * Allocate a new fscrypt_master_key which contains the given secret, set it as
+ * the payload of a new 'struct key' of type fscrypt, and link the 'struct key'
+ * into the given keyring. Synchronized by fscrypt_add_key_mutex.
+ */
+static int add_new_master_key(struct fscrypt_master_key_secret *secret,
+ const struct fscrypt_key_specifier *mk_spec,
+ struct key *keyring)
+{
+ struct fscrypt_master_key *mk;
+ char description[FSCRYPT_MK_DESCRIPTION_SIZE];
+ struct key *key;
+ int err;
+
+ mk = kzalloc(sizeof(*mk), GFP_KERNEL);
+ if (!mk)
+ return -ENOMEM;
+
+ mk->mk_spec = *mk_spec;
+
+ move_master_key_secret(&mk->mk_secret, secret);
+ init_rwsem(&mk->mk_secret_sem);
+
+ refcount_set(&mk->mk_refcount, 1); /* secret is present */
+ INIT_LIST_HEAD(&mk->mk_decrypted_inodes);
+ spin_lock_init(&mk->mk_decrypted_inodes_lock);
+
+ if (mk_spec->type == FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER) {
+ err = allocate_master_key_users_keyring(mk);
+ if (err)
+ goto out_free_mk;
+ err = add_master_key_user(mk);
+ if (err)
+ goto out_free_mk;
+ }
+
+ /*
+ * Note that we don't charge this key to anyone's quota, since when
+ * ->mk_users is in use those keys are charged instead, and otherwise
+ * (when ->mk_users isn't in use) only root can add these keys.
+ */
+ format_mk_description(description, mk_spec);
+ key = key_alloc(&key_type_fscrypt, description,
+ GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
+ KEY_POS_SEARCH | KEY_USR_SEARCH | KEY_USR_VIEW,
+ KEY_ALLOC_NOT_IN_QUOTA, NULL);
+ if (IS_ERR(key)) {
+ err = PTR_ERR(key);
+ goto out_free_mk;
+ }
+ err = key_instantiate_and_link(key, mk, sizeof(*mk), keyring, NULL);
+ key_put(key);
+ if (err)
+ goto out_free_mk;
+
+ return 0;
+
+out_free_mk:
+ free_master_key(mk);
+ return err;
+}
+
+#define KEY_DEAD 1
+
+static int add_existing_master_key(struct fscrypt_master_key *mk,
+ struct fscrypt_master_key_secret *secret)
+{
+ struct key *mk_user;
+ bool rekey;
+ int err;
+
+ /*
+ * If the current user is already in ->mk_users, then there's nothing to
+ * do. (Not applicable for v1 policy keys, which have NULL ->mk_users.)
+ */
+ if (mk->mk_users) {
+ mk_user = find_master_key_user(mk);
+ if (mk_user != ERR_PTR(-ENOKEY)) {
+ if (IS_ERR(mk_user))
+ return PTR_ERR(mk_user);
+ key_put(mk_user);
+ return 0;
+ }
+ }
+
+ /* If we'll be re-adding ->mk_secret, try to take the reference. */
+ rekey = !is_master_key_secret_present(&mk->mk_secret);
+ if (rekey && !refcount_inc_not_zero(&mk->mk_refcount))
+ return KEY_DEAD;
+
+ /* Add the current user to ->mk_users, if applicable. */
+ if (mk->mk_users) {
+ err = add_master_key_user(mk);
+ if (err) {
+ if (rekey && refcount_dec_and_test(&mk->mk_refcount))
+ return KEY_DEAD;
+ return err;
+ }
+ }
+
+ /* Re-add the secret if needed. */
+ if (rekey) {
+ down_write(&mk->mk_secret_sem);
+ move_master_key_secret(&mk->mk_secret, secret);
+ up_write(&mk->mk_secret_sem);
+ }
+ return 0;
+}
+
+static int add_master_key(struct super_block *sb,
+ struct fscrypt_master_key_secret *secret,
+ const struct fscrypt_key_specifier *mk_spec)
+{
+ static DEFINE_MUTEX(fscrypt_add_key_mutex);
+ struct key *key;
+ int err;
+
+ mutex_lock(&fscrypt_add_key_mutex); /* serialize find + link */
+retry:
+ key = fscrypt_find_master_key(sb, mk_spec);
+ if (IS_ERR(key)) {
+ err = PTR_ERR(key);
+ if (err != -ENOKEY)
+ goto out_unlock;
+ /* Didn't find the key in ->s_master_keys. Add it. */
+ err = allocate_filesystem_keyring(sb);
+ if (err)
+ goto out_unlock;
+ err = add_new_master_key(secret, mk_spec, sb->s_master_keys);
+ } else {
+ /*
+ * Found the key in ->s_master_keys. Re-add the secret if
+ * needed, and add the user to ->mk_users if needed.
+ */
+ down_write(&key->sem);
+ err = add_existing_master_key(key->payload.data[0], secret);
+ up_write(&key->sem);
+ if (err == KEY_DEAD) {
+ /* Key being removed or needs to be removed */
+ key_invalidate(key);
+ key_put(key);
+ goto retry;
+ }
+ key_put(key);
+ }
+out_unlock:
+ mutex_unlock(&fscrypt_add_key_mutex);
+ return err;
+}
+
+/*
+ * Add a master encryption key to the filesystem, causing all files which were
+ * encrypted with it to appear "unlocked" (decrypted) when accessed.
+ *
+ * When adding a key for use by v1 encryption policies, this ioctl is
+ * privileged, and userspace must provide the 'key_descriptor'.
+ *
+ * When adding a key for use by v2+ encryption policies, this ioctl is
+ * unprivileged. This is needed, in general, to allow non-root users to use
+ * encryption without encountering the visibility problems of process-subscribed
+ * keyrings and the inability to properly remove keys. This works by having
+ * each key identified by its cryptographically secure hash --- the
+ * 'key_identifier'. The cryptographic hash ensures that a malicious user
+ * cannot add the wrong key for a given identifier. Furthermore, each added key
+ * is charged to the appropriate user's quota for the keyrings service, which
+ * prevents a malicious user from adding too many keys. Finally, we forbid a
+ * user from removing a key while other users have added it too, which prevents
+ * a user who knows another user's key from causing a denial-of-service by
+ * removing it at an inopportune time. (We tolerate that a user who knows a key
+ * can prevent other users from removing it.)
+ *
+ * For more details, see the "FS_IOC_ADD_ENCRYPTION_KEY" section of
+ * Documentation/filesystems/fscrypt.rst.
+ */
+int fscrypt_ioctl_add_key(struct file *filp, void __user *_uarg)
+{
+ struct super_block *sb = file_inode(filp)->i_sb;
+ struct fscrypt_add_key_arg __user *uarg = _uarg;
+ struct fscrypt_add_key_arg arg;
+ struct fscrypt_master_key_secret secret;
+ int err;
+
+ if (copy_from_user(&arg, uarg, sizeof(arg)))
+ return -EFAULT;
+
+ if (!valid_key_spec(&arg.key_spec))
+ return -EINVAL;
+
+ if (arg.raw_size < FSCRYPT_MIN_KEY_SIZE ||
+ arg.raw_size > FSCRYPT_MAX_KEY_SIZE)
+ return -EINVAL;
+
+ if (memchr_inv(arg.__reserved, 0, sizeof(arg.__reserved)))
+ return -EINVAL;
+
+ memset(&secret, 0, sizeof(secret));
+ secret.size = arg.raw_size;
+ err = -EFAULT;
+ if (copy_from_user(secret.raw, uarg->raw, secret.size))
+ goto out_wipe_secret;
+
+ switch (arg.key_spec.type) {
+ case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR:
+ /*
+ * Only root can add keys that are identified by an arbitrary
+ * descriptor rather than by a cryptographic hash --- since
+ * otherwise a malicious user could add the wrong key.
+ */
+ err = -EACCES;
+ if (!capable(CAP_SYS_ADMIN))
+ goto out_wipe_secret;
+ break;
+ case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER:
+ err = fscrypt_init_hkdf(&secret.hkdf, secret.raw, secret.size);
+ if (err)
+ goto out_wipe_secret;
+
+ /*
+ * Now that the HKDF context is initialized, the raw key is no
+ * longer needed.
+ */
+ memzero_explicit(secret.raw, secret.size);
+
+ /* Calculate the key identifier and return it to userspace. */
+ err = fscrypt_hkdf_expand(&secret.hkdf,
+ HKDF_CONTEXT_KEY_IDENTIFIER,
+ NULL, 0, arg.key_spec.u.identifier,
+ FSCRYPT_KEY_IDENTIFIER_SIZE);
+ if (err)
+ goto out_wipe_secret;
+ err = -EFAULT;
+ if (copy_to_user(uarg->key_spec.u.identifier,
+ arg.key_spec.u.identifier,
+ FSCRYPT_KEY_IDENTIFIER_SIZE))
+ goto out_wipe_secret;
+ break;
+ default:
+ WARN_ON(1);
+ err = -EINVAL;
+ goto out_wipe_secret;
+ }
+
+ err = add_master_key(sb, &secret, &arg.key_spec);
+out_wipe_secret:
+ wipe_master_key_secret(&secret);
+ return err;
+}
+EXPORT_SYMBOL_GPL(fscrypt_ioctl_add_key);
+
+/*
+ * Verify that the current user has added a master key with the given identifier
+ * (returns -ENOKEY if not). This is needed to prevent a user from encrypting
+ * their files using some other user's key which they don't actually know.
+ * Cryptographically this isn't much of a problem, but the semantics of this
+ * would be a bit weird, so it's best to just forbid it.
+ *
+ * The system administrator (CAP_FOWNER) can override this, which should be
+ * enough for any use cases where encryption policies are being set using keys
+ * that were chosen ahead of time but aren't available at the moment.
+ *
+ * Note that the key may have already removed by the time this returns, but
+ * that's okay; we just care whether the key was there at some point.
+ *
+ * Return: 0 if the key is added, -ENOKEY if it isn't, or another -errno code
+ */
+int fscrypt_verify_key_added(struct super_block *sb,
+ const u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE])
+{
+ struct fscrypt_key_specifier mk_spec;
+ struct key *key, *mk_user;
+ struct fscrypt_master_key *mk;
+ int err;
+
+ mk_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
+ memcpy(mk_spec.u.identifier, identifier, FSCRYPT_KEY_IDENTIFIER_SIZE);
+
+ key = fscrypt_find_master_key(sb, &mk_spec);
+ if (IS_ERR(key)) {
+ err = PTR_ERR(key);
+ goto out;
+ }
+ mk = key->payload.data[0];
+ mk_user = find_master_key_user(mk);
+ if (IS_ERR(mk_user)) {
+ err = PTR_ERR(mk_user);
+ } else {
+ key_put(mk_user);
+ err = 0;
+ }
+ key_put(key);
+out:
+ if (err == -ENOKEY && capable(CAP_FOWNER))
+ err = 0;
+ return err;
+}
+
+/*
+ * Try to evict the inode's dentries from the dentry cache. If the inode is a
+ * directory, then it can have at most one dentry; however, that dentry may be
+ * pinned by child dentries, so first try to evict the children too.
+ */
+static void shrink_dcache_inode(struct inode *inode)
+{
+ struct dentry *dentry;
+
+ if (S_ISDIR(inode->i_mode)) {
+ dentry = d_find_any_alias(inode);
+ if (dentry) {
+ shrink_dcache_parent(dentry);
+ dput(dentry);
+ }
+ }
+ d_prune_aliases(inode);
+}
+
+static void evict_dentries_for_decrypted_inodes(struct fscrypt_master_key *mk)
+{
+ struct fscrypt_info *ci;
+ struct inode *inode;
+ struct inode *toput_inode = NULL;
+
+ spin_lock(&mk->mk_decrypted_inodes_lock);
+
+ list_for_each_entry(ci, &mk->mk_decrypted_inodes, ci_master_key_link) {
+ inode = ci->ci_inode;
+ spin_lock(&inode->i_lock);
+ if (inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW)) {
+ spin_unlock(&inode->i_lock);
+ continue;
+ }
+ __iget(inode);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&mk->mk_decrypted_inodes_lock);
+
+ shrink_dcache_inode(inode);
+ iput(toput_inode);
+ toput_inode = inode;
+
+ spin_lock(&mk->mk_decrypted_inodes_lock);
+ }
+
+ spin_unlock(&mk->mk_decrypted_inodes_lock);
+ iput(toput_inode);
+}
+
+static int check_for_busy_inodes(struct super_block *sb,
+ struct fscrypt_master_key *mk)
+{
+ struct list_head *pos;
+ size_t busy_count = 0;
+ unsigned long ino;
+ struct dentry *dentry;
+ char _path[256];
+ char *path = NULL;
+
+ spin_lock(&mk->mk_decrypted_inodes_lock);
+
+ list_for_each(pos, &mk->mk_decrypted_inodes)
+ busy_count++;
+
+ if (busy_count == 0) {
+ spin_unlock(&mk->mk_decrypted_inodes_lock);
+ return 0;
+ }
+
+ {
+ /* select an example file to show for debugging purposes */
+ struct inode *inode =
+ list_first_entry(&mk->mk_decrypted_inodes,
+ struct fscrypt_info,
+ ci_master_key_link)->ci_inode;
+ ino = inode->i_ino;
+ dentry = d_find_alias(inode);
+ }
+ spin_unlock(&mk->mk_decrypted_inodes_lock);
+
+ if (dentry) {
+ path = dentry_path(dentry, _path, sizeof(_path));
+ dput(dentry);
+ }
+ if (IS_ERR_OR_NULL(path))
+ path = "(unknown)";
+
+ fscrypt_warn(NULL,
+ "%s: %zu inode(s) still busy after removing key with %s %*phN, including ino %lu (%s)",
+ sb->s_id, busy_count, master_key_spec_type(&mk->mk_spec),
+ master_key_spec_len(&mk->mk_spec), (u8 *)&mk->mk_spec.u,
+ ino, path);
+ return -EBUSY;
+}
+
+static int try_to_lock_encrypted_files(struct super_block *sb,
+ struct fscrypt_master_key *mk)
+{
+ int err1;
+ int err2;
+
+ /*
+ * An inode can't be evicted while it is dirty or has dirty pages.
+ * Thus, we first have to clean the inodes in ->mk_decrypted_inodes.
+ *
+ * Just do it the easy way: call sync_filesystem(). It's overkill, but
+ * it works, and it's more important to minimize the amount of caches we
+ * drop than the amount of data we sync. Also, unprivileged users can
+ * already call sync_filesystem() via sys_syncfs() or sys_sync().
+ */
+ down_read(&sb->s_umount);
+ err1 = sync_filesystem(sb);
+ up_read(&sb->s_umount);
+ /* If a sync error occurs, still try to evict as much as possible. */
+
+ /*
+ * Inodes are pinned by their dentries, so we have to evict their
+ * dentries. shrink_dcache_sb() would suffice, but would be overkill
+ * and inappropriate for use by unprivileged users. So instead go
+ * through the inodes' alias lists and try to evict each dentry.
+ */
+ evict_dentries_for_decrypted_inodes(mk);
+
+ /*
+ * evict_dentries_for_decrypted_inodes() already iput() each inode in
+ * the list; any inodes for which that dropped the last reference will
+ * have been evicted due to fscrypt_drop_inode() detecting the key
+ * removal and telling the VFS to evict the inode. So to finish, we
+ * just need to check whether any inodes couldn't be evicted.
+ */
+ err2 = check_for_busy_inodes(sb, mk);
+
+ return err1 ?: err2;
+}
+
+/*
+ * Try to remove an fscrypt master encryption key.
+ *
+ * FS_IOC_REMOVE_ENCRYPTION_KEY (all_users=false) removes the current user's
+ * claim to the key, then removes the key itself if no other users have claims.
+ * FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS (all_users=true) always removes the
+ * key itself.
+ *
+ * To "remove the key itself", first we wipe the actual master key secret, so
+ * that no more inodes can be unlocked with it. Then we try to evict all cached
+ * inodes that had been unlocked with the key.
+ *
+ * If all inodes were evicted, then we unlink the fscrypt_master_key from the
+ * keyring. Otherwise it remains in the keyring in the "incompletely removed"
+ * state (without the actual secret key) where it tracks the list of remaining
+ * inodes. Userspace can execute the ioctl again later to retry eviction, or
+ * alternatively can re-add the secret key again.
+ *
+ * For more details, see the "Removing keys" section of
+ * Documentation/filesystems/fscrypt.rst.
+ */
+static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
+{
+ struct super_block *sb = file_inode(filp)->i_sb;
+ struct fscrypt_remove_key_arg __user *uarg = _uarg;
+ struct fscrypt_remove_key_arg arg;
+ struct key *key;
+ struct fscrypt_master_key *mk;
+ u32 status_flags = 0;
+ int err;
+ bool dead;
+
+ if (copy_from_user(&arg, uarg, sizeof(arg)))
+ return -EFAULT;
+
+ if (!valid_key_spec(&arg.key_spec))
+ return -EINVAL;
+
+ if (memchr_inv(arg.__reserved, 0, sizeof(arg.__reserved)))
+ return -EINVAL;
+
+ /*
+ * Only root can add and remove keys that are identified by an arbitrary
+ * descriptor rather than by a cryptographic hash.
+ */
+ if (arg.key_spec.type == FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR &&
+ !capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ /* Find the key being removed. */
+ key = fscrypt_find_master_key(sb, &arg.key_spec);
+ if (IS_ERR(key))
+ return PTR_ERR(key);
+ mk = key->payload.data[0];
+
+ down_write(&key->sem);
+
+ /* If relevant, remove current user's (or all users) claim to the key */
+ if (mk->mk_users && mk->mk_users->keys.nr_leaves_on_tree != 0) {
+ if (all_users)
+ err = keyring_clear(mk->mk_users);
+ else
+ err = remove_master_key_user(mk);
+ if (err) {
+ up_write(&key->sem);
+ goto out_put_key;
+ }
+ if (mk->mk_users->keys.nr_leaves_on_tree != 0) {
+ /*
+ * Other users have still added the key too. We removed
+ * the current user's claim to the key, but we still
+ * can't remove the key itself.
+ */
+ status_flags |=
+ FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS;
+ err = 0;
+ up_write(&key->sem);
+ goto out_put_key;
+ }
+ }
+
+ /* No user claims remaining. Go ahead and wipe the secret. */
+ dead = false;
+ if (is_master_key_secret_present(&mk->mk_secret)) {
+ down_write(&mk->mk_secret_sem);
+ wipe_master_key_secret(&mk->mk_secret);
+ dead = refcount_dec_and_test(&mk->mk_refcount);
+ up_write(&mk->mk_secret_sem);
+ }
+ up_write(&key->sem);
+ if (dead) {
+ /*
+ * No inodes reference the key, and we wiped the secret, so the
+ * key object is free to be removed from the keyring.
+ */
+ key_invalidate(key);
+ err = 0;
+ } else {
+ /* Some inodes still reference this key; try to evict them. */
+ err = try_to_lock_encrypted_files(sb, mk);
+ if (err == -EBUSY) {
+ status_flags |=
+ FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY;
+ err = 0;
+ }
+ }
+ /*
+ * We return 0 if we successfully did something: removed a claim to the
+ * key, wiped the secret, or tried locking the files again. Users need
+ * to check the informational status flags if they care whether the key
+ * has been fully removed including all files locked.
+ */
+out_put_key:
+ key_put(key);
+ if (err == 0)
+ err = put_user(status_flags, &uarg->removal_status_flags);
+ return err;
+}
+
+int fscrypt_ioctl_remove_key(struct file *filp, void __user *uarg)
+{
+ return do_remove_key(filp, uarg, false);
+}
+EXPORT_SYMBOL_GPL(fscrypt_ioctl_remove_key);
+
+int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *uarg)
+{
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+ return do_remove_key(filp, uarg, true);
+}
+EXPORT_SYMBOL_GPL(fscrypt_ioctl_remove_key_all_users);
+
+/*
+ * Retrieve the status of an fscrypt master encryption key.
+ *
+ * We set ->status to indicate whether the key is absent, present, or
+ * incompletely removed. "Incompletely removed" means that the master key
+ * secret has been removed, but some files which had been unlocked with it are
+ * still in use. This field allows applications to easily determine the state
+ * of an encrypted directory without using a hack such as trying to open a
+ * regular file in it (which can confuse the "incompletely removed" state with
+ * absent or present).
+ *
+ * In addition, for v2 policy keys we allow applications to determine, via
+ * ->status_flags and ->user_count, whether the key has been added by the
+ * current user, by other users, or by both. Most applications should not need
+ * this, since ordinarily only one user should know a given key. However, if a
+ * secret key is shared by multiple users, applications may wish to add an
+ * already-present key to prevent other users from removing it. This ioctl can
+ * be used to check whether that really is the case before the work is done to
+ * add the key --- which might e.g. require prompting the user for a passphrase.
+ *
+ * For more details, see the "FS_IOC_GET_ENCRYPTION_KEY_STATUS" section of
+ * Documentation/filesystems/fscrypt.rst.
+ */
+int fscrypt_ioctl_get_key_status(struct file *filp, void __user *uarg)
+{
+ struct super_block *sb = file_inode(filp)->i_sb;
+ struct fscrypt_get_key_status_arg arg;
+ struct key *key;
+ struct fscrypt_master_key *mk;
+ int err;
+
+ if (copy_from_user(&arg, uarg, sizeof(arg)))
+ return -EFAULT;
+
+ if (!valid_key_spec(&arg.key_spec))
+ return -EINVAL;
+
+ if (memchr_inv(arg.__reserved, 0, sizeof(arg.__reserved)))
+ return -EINVAL;
+
+ arg.status_flags = 0;
+ arg.user_count = 0;
+ memset(arg.__out_reserved, 0, sizeof(arg.__out_reserved));
+
+ key = fscrypt_find_master_key(sb, &arg.key_spec);
+ if (IS_ERR(key)) {
+ if (key != ERR_PTR(-ENOKEY))
+ return PTR_ERR(key);
+ arg.status = FSCRYPT_KEY_STATUS_ABSENT;
+ err = 0;
+ goto out;
+ }
+ mk = key->payload.data[0];
+ down_read(&key->sem);
+
+ if (!is_master_key_secret_present(&mk->mk_secret)) {
+ arg.status = FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED;
+ err = 0;
+ goto out_release_key;
+ }
+
+ arg.status = FSCRYPT_KEY_STATUS_PRESENT;
+ if (mk->mk_users) {
+ struct key *mk_user;
+
+ arg.user_count = mk->mk_users->keys.nr_leaves_on_tree;
+ mk_user = find_master_key_user(mk);
+ if (!IS_ERR(mk_user)) {
+ arg.status_flags |=
+ FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF;
+ key_put(mk_user);
+ } else if (mk_user != ERR_PTR(-ENOKEY)) {
+ err = PTR_ERR(mk_user);
+ goto out_release_key;
+ }
+ }
+ err = 0;
+out_release_key:
+ up_read(&key->sem);
+ key_put(key);
+out:
+ if (!err && copy_to_user(uarg, &arg, sizeof(arg)))
+ err = -EFAULT;
+ return err;
+}
+EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_key_status);
+
+int __init fscrypt_init_keyring(void)
+{
+ int err;
+
+ err = register_key_type(&key_type_fscrypt);
+ if (err)
+ return err;
+
+ err = register_key_type(&key_type_fscrypt_user);
+ if (err)
+ goto err_unregister_fscrypt;
+
+ return 0;
+
+err_unregister_fscrypt:
+ unregister_key_type(&key_type_fscrypt);
+ return err;
+}
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
new file mode 100644
index 000000000000..d71c2d6dd162
--- /dev/null
+++ b/fs/crypto/keysetup.c
@@ -0,0 +1,591 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Key setup facility for FS encryption support.
+ *
+ * Copyright (C) 2015, Google, Inc.
+ *
+ * Originally written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar.
+ * Heavily modified since then.
+ */
+
+#include <crypto/aes.h>
+#include <crypto/sha.h>
+#include <crypto/skcipher.h>
+#include <linux/key.h>
+
+#include "fscrypt_private.h"
+
+static struct crypto_shash *essiv_hash_tfm;
+
+static struct fscrypt_mode available_modes[] = {
+ [FSCRYPT_MODE_AES_256_XTS] = {
+ .friendly_name = "AES-256-XTS",
+ .cipher_str = "xts(aes)",
+ .keysize = 64,
+ .ivsize = 16,
+ },
+ [FSCRYPT_MODE_AES_256_CTS] = {
+ .friendly_name = "AES-256-CTS-CBC",
+ .cipher_str = "cts(cbc(aes))",
+ .keysize = 32,
+ .ivsize = 16,
+ },
+ [FSCRYPT_MODE_AES_128_CBC] = {
+ .friendly_name = "AES-128-CBC",
+ .cipher_str = "cbc(aes)",
+ .keysize = 16,
+ .ivsize = 16,
+ .needs_essiv = true,
+ },
+ [FSCRYPT_MODE_AES_128_CTS] = {
+ .friendly_name = "AES-128-CTS-CBC",
+ .cipher_str = "cts(cbc(aes))",
+ .keysize = 16,
+ .ivsize = 16,
+ },
+ [FSCRYPT_MODE_ADIANTUM] = {
+ .friendly_name = "Adiantum",
+ .cipher_str = "adiantum(xchacha12,aes)",
+ .keysize = 32,
+ .ivsize = 32,
+ },
+};
+
+static struct fscrypt_mode *
+select_encryption_mode(const union fscrypt_policy *policy,
+ const struct inode *inode)
+{
+ if (S_ISREG(inode->i_mode))
+ return &available_modes[fscrypt_policy_contents_mode(policy)];
+
+ if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
+ return &available_modes[fscrypt_policy_fnames_mode(policy)];
+
+ WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n",
+ inode->i_ino, (inode->i_mode & S_IFMT));
+ return ERR_PTR(-EINVAL);
+}
+
+/* Create a symmetric cipher object for the given encryption mode and key */
+struct crypto_skcipher *fscrypt_allocate_skcipher(struct fscrypt_mode *mode,
+ const u8 *raw_key,
+ const struct inode *inode)
+{
+ struct crypto_skcipher *tfm;
+ int err;
+
+ tfm = crypto_alloc_skcipher(mode->cipher_str, 0, 0);
+ if (IS_ERR(tfm)) {
+ if (PTR_ERR(tfm) == -ENOENT) {
+ fscrypt_warn(inode,
+ "Missing crypto API support for %s (API name: \"%s\")",
+ mode->friendly_name, mode->cipher_str);
+ return ERR_PTR(-ENOPKG);
+ }
+ fscrypt_err(inode, "Error allocating '%s' transform: %ld",
+ mode->cipher_str, PTR_ERR(tfm));
+ return tfm;
+ }
+ if (unlikely(!mode->logged_impl_name)) {
+ /*
+ * fscrypt performance can vary greatly depending on which
+ * crypto algorithm implementation is used. Help people debug
+ * performance problems by logging the ->cra_driver_name the
+ * first time a mode is used. Note that multiple threads can
+ * race here, but it doesn't really matter.
+ */
+ mode->logged_impl_name = true;
+ pr_info("fscrypt: %s using implementation \"%s\"\n",
+ mode->friendly_name,
+ crypto_skcipher_alg(tfm)->base.cra_driver_name);
+ }
+ crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
+ err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize);
+ if (err)
+ goto err_free_tfm;
+
+ return tfm;
+
+err_free_tfm:
+ crypto_free_skcipher(tfm);
+ return ERR_PTR(err);
+}
+
+static int derive_essiv_salt(const u8 *key, int keysize, u8 *salt)
+{
+ struct crypto_shash *tfm = READ_ONCE(essiv_hash_tfm);
+
+ /* init hash transform on demand */
+ if (unlikely(!tfm)) {
+ struct crypto_shash *prev_tfm;
+
+ tfm = crypto_alloc_shash("sha256", 0, 0);
+ if (IS_ERR(tfm)) {
+ if (PTR_ERR(tfm) == -ENOENT) {
+ fscrypt_warn(NULL,
+ "Missing crypto API support for SHA-256");
+ return -ENOPKG;
+ }
+ fscrypt_err(NULL,
+ "Error allocating SHA-256 transform: %ld",
+ PTR_ERR(tfm));
+ return PTR_ERR(tfm);
+ }
+ prev_tfm = cmpxchg(&essiv_hash_tfm, NULL, tfm);
+ if (prev_tfm) {
+ crypto_free_shash(tfm);
+ tfm = prev_tfm;
+ }
+ }
+
+ {
+ SHASH_DESC_ON_STACK(desc, tfm);
+ desc->tfm = tfm;
+
+ return crypto_shash_digest(desc, key, keysize, salt);
+ }
+}
+
+static int init_essiv_generator(struct fscrypt_info *ci, const u8 *raw_key,
+ int keysize)
+{
+ int err;
+ struct crypto_cipher *essiv_tfm;
+ u8 salt[SHA256_DIGEST_SIZE];
+
+ if (WARN_ON(ci->ci_mode->ivsize != AES_BLOCK_SIZE))
+ return -EINVAL;
+
+ essiv_tfm = crypto_alloc_cipher("aes", 0, 0);
+ if (IS_ERR(essiv_tfm))
+ return PTR_ERR(essiv_tfm);
+
+ ci->ci_essiv_tfm = essiv_tfm;
+
+ err = derive_essiv_salt(raw_key, keysize, salt);
+ if (err)
+ goto out;
+
+ /*
+ * Using SHA256 to derive the salt/key will result in AES-256 being
+ * used for IV generation. File contents encryption will still use the
+ * configured keysize (AES-128) nevertheless.
+ */
+ err = crypto_cipher_setkey(essiv_tfm, salt, sizeof(salt));
+ if (err)
+ goto out;
+
+out:
+ memzero_explicit(salt, sizeof(salt));
+ return err;
+}
+
+/* Given the per-file key, set up the file's crypto transform object(s) */
+int fscrypt_set_derived_key(struct fscrypt_info *ci, const u8 *derived_key)
+{
+ struct fscrypt_mode *mode = ci->ci_mode;
+ struct crypto_skcipher *ctfm;
+ int err;
+
+ ctfm = fscrypt_allocate_skcipher(mode, derived_key, ci->ci_inode);
+ if (IS_ERR(ctfm))
+ return PTR_ERR(ctfm);
+
+ ci->ci_ctfm = ctfm;
+
+ if (mode->needs_essiv) {
+ err = init_essiv_generator(ci, derived_key, mode->keysize);
+ if (err) {
+ fscrypt_warn(ci->ci_inode,
+ "Error initializing ESSIV generator: %d",
+ err);
+ return err;
+ }
+ }
+ return 0;
+}
+
+static int setup_per_mode_key(struct fscrypt_info *ci,
+ struct fscrypt_master_key *mk)
+{
+ struct fscrypt_mode *mode = ci->ci_mode;
+ u8 mode_num = mode - available_modes;
+ struct crypto_skcipher *tfm, *prev_tfm;
+ u8 mode_key[FSCRYPT_MAX_KEY_SIZE];
+ int err;
+
+ if (WARN_ON(mode_num >= ARRAY_SIZE(mk->mk_mode_keys)))
+ return -EINVAL;
+
+ /* pairs with cmpxchg() below */
+ tfm = READ_ONCE(mk->mk_mode_keys[mode_num]);
+ if (likely(tfm != NULL))
+ goto done;
+
+ BUILD_BUG_ON(sizeof(mode_num) != 1);
+ err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,
+ HKDF_CONTEXT_PER_MODE_KEY,
+ &mode_num, sizeof(mode_num),
+ mode_key, mode->keysize);
+ if (err)
+ return err;
+ tfm = fscrypt_allocate_skcipher(mode, mode_key, ci->ci_inode);
+ memzero_explicit(mode_key, mode->keysize);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ /* pairs with READ_ONCE() above */
+ prev_tfm = cmpxchg(&mk->mk_mode_keys[mode_num], NULL, tfm);
+ if (prev_tfm != NULL) {
+ crypto_free_skcipher(tfm);
+ tfm = prev_tfm;
+ }
+done:
+ ci->ci_ctfm = tfm;
+ return 0;
+}
+
+static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci,
+ struct fscrypt_master_key *mk)
+{
+ u8 derived_key[FSCRYPT_MAX_KEY_SIZE];
+ int err;
+
+ if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) {
+ /*
+ * DIRECT_KEY: instead of deriving per-file keys, the per-file
+ * nonce will be included in all the IVs. But unlike v1
+ * policies, for v2 policies in this case we don't encrypt with
+ * the master key directly but rather derive a per-mode key.
+ * This ensures that the master key is consistently used only
+ * for HKDF, avoiding key reuse issues.
+ */
+ if (!fscrypt_mode_supports_direct_key(ci->ci_mode)) {
+ fscrypt_warn(ci->ci_inode,
+ "Direct key flag not allowed with %s",
+ ci->ci_mode->friendly_name);
+ return -EINVAL;
+ }
+ return setup_per_mode_key(ci, mk);
+ }
+
+ err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,
+ HKDF_CONTEXT_PER_FILE_KEY,
+ ci->ci_nonce, FS_KEY_DERIVATION_NONCE_SIZE,
+ derived_key, ci->ci_mode->keysize);
+ if (err)
+ return err;
+
+ err = fscrypt_set_derived_key(ci, derived_key);
+ memzero_explicit(derived_key, ci->ci_mode->keysize);
+ return err;
+}
+
+/*
+ * Find the master key, then set up the inode's actual encryption key.
+ *
+ * If the master key is found in the filesystem-level keyring, then the
+ * corresponding 'struct key' is returned in *master_key_ret with
+ * ->mk_secret_sem read-locked. This is needed to ensure that only one task
+ * links the fscrypt_info into ->mk_decrypted_inodes (as multiple tasks may race
+ * to create an fscrypt_info for the same inode), and to synchronize the master
+ * key being removed with a new inode starting to use it.
+ */
+static int setup_file_encryption_key(struct fscrypt_info *ci,
+ struct key **master_key_ret)
+{
+ struct key *key;
+ struct fscrypt_master_key *mk = NULL;
+ struct fscrypt_key_specifier mk_spec;
+ int err;
+
+ switch (ci->ci_policy.version) {
+ case FSCRYPT_POLICY_V1:
+ mk_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;
+ memcpy(mk_spec.u.descriptor,
+ ci->ci_policy.v1.master_key_descriptor,
+ FSCRYPT_KEY_DESCRIPTOR_SIZE);
+ break;
+ case FSCRYPT_POLICY_V2:
+ mk_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
+ memcpy(mk_spec.u.identifier,
+ ci->ci_policy.v2.master_key_identifier,
+ FSCRYPT_KEY_IDENTIFIER_SIZE);
+ break;
+ default:
+ WARN_ON(1);
+ return -EINVAL;
+ }
+
+ key = fscrypt_find_master_key(ci->ci_inode->i_sb, &mk_spec);
+ if (IS_ERR(key)) {
+ if (key != ERR_PTR(-ENOKEY) ||
+ ci->ci_policy.version != FSCRYPT_POLICY_V1)
+ return PTR_ERR(key);
+
+ /*
+ * As a legacy fallback for v1 policies, search for the key in
+ * the current task's subscribed keyrings too. Don't move this
+ * to before the search of ->s_master_keys, since users
+ * shouldn't be able to override filesystem-level keys.
+ */
+ return fscrypt_setup_v1_file_key_via_subscribed_keyrings(ci);
+ }
+
+ mk = key->payload.data[0];
+ down_read(&mk->mk_secret_sem);
+
+ /* Has the secret been removed (via FS_IOC_REMOVE_ENCRYPTION_KEY)? */
+ if (!is_master_key_secret_present(&mk->mk_secret)) {
+ err = -ENOKEY;
+ goto out_release_key;
+ }
+
+ /*
+ * Require that the master key be at least as long as the derived key.
+ * Otherwise, the derived key cannot possibly contain as much entropy as
+ * that required by the encryption mode it will be used for. For v1
+ * policies it's also required for the KDF to work at all.
+ */
+ if (mk->mk_secret.size < ci->ci_mode->keysize) {
+ fscrypt_warn(NULL,
+ "key with %s %*phN is too short (got %u bytes, need %u+ bytes)",
+ master_key_spec_type(&mk_spec),
+ master_key_spec_len(&mk_spec), (u8 *)&mk_spec.u,
+ mk->mk_secret.size, ci->ci_mode->keysize);
+ err = -ENOKEY;
+ goto out_release_key;
+ }
+
+ switch (ci->ci_policy.version) {
+ case FSCRYPT_POLICY_V1:
+ err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw);
+ break;
+ case FSCRYPT_POLICY_V2:
+ err = fscrypt_setup_v2_file_key(ci, mk);
+ break;
+ default:
+ WARN_ON(1);
+ err = -EINVAL;
+ break;
+ }
+ if (err)
+ goto out_release_key;
+
+ *master_key_ret = key;
+ return 0;
+
+out_release_key:
+ up_read(&mk->mk_secret_sem);
+ key_put(key);
+ return err;
+}
+
+static void put_crypt_info(struct fscrypt_info *ci)
+{
+ struct key *key;
+
+ if (!ci)
+ return;
+
+ if (ci->ci_direct_key) {
+ fscrypt_put_direct_key(ci->ci_direct_key);
+ } else if ((ci->ci_ctfm != NULL || ci->ci_essiv_tfm != NULL) &&
+ !fscrypt_is_direct_key_policy(&ci->ci_policy)) {
+ crypto_free_skcipher(ci->ci_ctfm);
+ crypto_free_cipher(ci->ci_essiv_tfm);
+ }
+
+ key = ci->ci_master_key;
+ if (key) {
+ struct fscrypt_master_key *mk = key->payload.data[0];
+
+ /*
+ * Remove this inode from the list of inodes that were unlocked
+ * with the master key.
+ *
+ * In addition, if we're removing the last inode from a key that
+ * already had its secret removed, invalidate the key so that it
+ * gets removed from ->s_master_keys.
+ */
+ spin_lock(&mk->mk_decrypted_inodes_lock);
+ list_del(&ci->ci_master_key_link);
+ spin_unlock(&mk->mk_decrypted_inodes_lock);
+ if (refcount_dec_and_test(&mk->mk_refcount))
+ key_invalidate(key);
+ key_put(key);
+ }
+ kmem_cache_free(fscrypt_info_cachep, ci);
+}
+
+int fscrypt_get_encryption_info(struct inode *inode)
+{
+ struct fscrypt_info *crypt_info;
+ union fscrypt_context ctx;
+ struct fscrypt_mode *mode;
+ struct key *master_key = NULL;
+ int res;
+
+ if (fscrypt_has_encryption_key(inode))
+ return 0;
+
+ res = fscrypt_initialize(inode->i_sb->s_cop->flags);
+ if (res)
+ return res;
+
+ res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
+ if (res < 0) {
+ if (!fscrypt_dummy_context_enabled(inode) ||
+ IS_ENCRYPTED(inode)) {
+ fscrypt_warn(inode,
+ "Error %d getting encryption context",
+ res);
+ return res;
+ }
+ /* Fake up a context for an unencrypted directory */
+ memset(&ctx, 0, sizeof(ctx));
+ ctx.version = FSCRYPT_CONTEXT_V1;
+ ctx.v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
+ ctx.v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
+ memset(ctx.v1.master_key_descriptor, 0x42,
+ FSCRYPT_KEY_DESCRIPTOR_SIZE);
+ res = sizeof(ctx.v1);
+ }
+
+ crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_NOFS);
+ if (!crypt_info)
+ return -ENOMEM;
+
+ crypt_info->ci_inode = inode;
+
+ res = fscrypt_policy_from_context(&crypt_info->ci_policy, &ctx, res);
+ if (res) {
+ fscrypt_warn(inode,
+ "Unrecognized or corrupt encryption context");
+ goto out;
+ }
+
+ switch (ctx.version) {
+ case FSCRYPT_CONTEXT_V1:
+ memcpy(crypt_info->ci_nonce, ctx.v1.nonce,
+ FS_KEY_DERIVATION_NONCE_SIZE);
+ break;
+ case FSCRYPT_CONTEXT_V2:
+ memcpy(crypt_info->ci_nonce, ctx.v2.nonce,
+ FS_KEY_DERIVATION_NONCE_SIZE);
+ break;
+ default:
+ WARN_ON(1);
+ res = -EINVAL;
+ goto out;
+ }
+
+ if (!fscrypt_supported_policy(&crypt_info->ci_policy, inode)) {
+ res = -EINVAL;
+ goto out;
+ }
+
+ mode = select_encryption_mode(&crypt_info->ci_policy, inode);
+ if (IS_ERR(mode)) {
+ res = PTR_ERR(mode);
+ goto out;
+ }
+ WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE);
+ crypt_info->ci_mode = mode;
+
+ res = setup_file_encryption_key(crypt_info, &master_key);
+ if (res)
+ goto out;
+
+ if (cmpxchg_release(&inode->i_crypt_info, NULL, crypt_info) == NULL) {
+ if (master_key) {
+ struct fscrypt_master_key *mk =
+ master_key->payload.data[0];
+
+ refcount_inc(&mk->mk_refcount);
+ crypt_info->ci_master_key = key_get(master_key);
+ spin_lock(&mk->mk_decrypted_inodes_lock);
+ list_add(&crypt_info->ci_master_key_link,
+ &mk->mk_decrypted_inodes);
+ spin_unlock(&mk->mk_decrypted_inodes_lock);
+ }
+ crypt_info = NULL;
+ }
+ res = 0;
+out:
+ if (master_key) {
+ struct fscrypt_master_key *mk = master_key->payload.data[0];
+
+ up_read(&mk->mk_secret_sem);
+ key_put(master_key);
+ }
+ if (res == -ENOKEY)
+ res = 0;
+ put_crypt_info(crypt_info);
+ return res;
+}
+EXPORT_SYMBOL(fscrypt_get_encryption_info);
+
+/**
+ * fscrypt_put_encryption_info - free most of an inode's fscrypt data
+ *
+ * Free the inode's fscrypt_info. Filesystems must call this when the inode is
+ * being evicted. An RCU grace period need not have elapsed yet.
+ */
+void fscrypt_put_encryption_info(struct inode *inode)
+{
+ put_crypt_info(inode->i_crypt_info);
+ inode->i_crypt_info = NULL;
+}
+EXPORT_SYMBOL(fscrypt_put_encryption_info);
+
+/**
+ * fscrypt_free_inode - free an inode's fscrypt data requiring RCU delay
+ *
+ * Free the inode's cached decrypted symlink target, if any. Filesystems must
+ * call this after an RCU grace period, just before they free the inode.
+ */
+void fscrypt_free_inode(struct inode *inode)
+{
+ if (IS_ENCRYPTED(inode) && S_ISLNK(inode->i_mode)) {
+ kfree(inode->i_link);
+ inode->i_link = NULL;
+ }
+}
+EXPORT_SYMBOL(fscrypt_free_inode);
+
+/**
+ * fscrypt_drop_inode - check whether the inode's master key has been removed
+ *
+ * Filesystems supporting fscrypt must call this from their ->drop_inode()
+ * method so that encrypted inodes are evicted as soon as they're no longer in
+ * use and their master key has been removed.
+ *
+ * Return: 1 if fscrypt wants the inode to be evicted now, otherwise 0
+ */
+int fscrypt_drop_inode(struct inode *inode)
+{
+ const struct fscrypt_info *ci = READ_ONCE(inode->i_crypt_info);
+ const struct fscrypt_master_key *mk;
+
+ /*
+ * If ci is NULL, then the inode doesn't have an encryption key set up
+ * so it's irrelevant. If ci_master_key is NULL, then the master key
+ * was provided via the legacy mechanism of the process-subscribed
+ * keyrings, so we don't know whether it's been removed or not.
+ */
+ if (!ci || !ci->ci_master_key)
+ return 0;
+ mk = ci->ci_master_key->payload.data[0];
+
+ /*
+ * Note: since we aren't holding ->mk_secret_sem, the result here can
+ * immediately become outdated. But there's no correctness problem with
+ * unnecessarily evicting. Nor is there a correctness problem with not
+ * evicting while iput() is racing with the key being removed, since
+ * then the thread removing the key will either evict the inode itself
+ * or will correctly detect that it wasn't evicted due to the race.
+ */
+ return !is_master_key_secret_present(&mk->mk_secret);
+}
+EXPORT_SYMBOL_GPL(fscrypt_drop_inode);
diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c
new file mode 100644
index 000000000000..ad1a36c370c3
--- /dev/null
+++ b/fs/crypto/keysetup_v1.c
@@ -0,0 +1,340 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Key setup for v1 encryption policies
+ *
+ * Copyright 2015, 2019 Google LLC
+ */
+
+/*
+ * This file implements compatibility functions for the original encryption
+ * policy version ("v1"), including:
+ *
+ * - Deriving per-file keys using the AES-128-ECB based KDF
+ * (rather than the new method of using HKDF-SHA512)
+ *
+ * - Retrieving fscrypt master keys from process-subscribed keyrings
+ * (rather than the new method of using a filesystem-level keyring)
+ *
+ * - Handling policies with the DIRECT_KEY flag set using a master key table
+ * (rather than the new method of implementing DIRECT_KEY with per-mode keys
+ * managed alongside the master keys in the filesystem-level keyring)
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/skcipher.h>
+#include <keys/user-type.h>
+#include <linux/hashtable.h>
+#include <linux/scatterlist.h>
+
+#include "fscrypt_private.h"
+
+/* Table of keys referenced by DIRECT_KEY policies */
+static DEFINE_HASHTABLE(fscrypt_direct_keys, 6); /* 6 bits = 64 buckets */
+static DEFINE_SPINLOCK(fscrypt_direct_keys_lock);
+
+/*
+ * v1 key derivation function. This generates the derived key by encrypting the
+ * master key with AES-128-ECB using the nonce as the AES key. This provides a
+ * unique derived key with sufficient entropy for each inode. However, it's
+ * nonstandard, non-extensible, doesn't evenly distribute the entropy from the
+ * master key, and is trivially reversible: an attacker who compromises a
+ * derived key can "decrypt" it to get back to the master key, then derive any
+ * other key. For all new code, use HKDF instead.
+ *
+ * The master key must be at least as long as the derived key. If the master
+ * key is longer, then only the first 'derived_keysize' bytes are used.
+ */
+static int derive_key_aes(const u8 *master_key,
+ const u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE],
+ u8 *derived_key, unsigned int derived_keysize)
+{
+ int res = 0;
+ struct skcipher_request *req = NULL;
+ DECLARE_CRYPTO_WAIT(wait);
+ struct scatterlist src_sg, dst_sg;
+ struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
+
+ if (IS_ERR(tfm)) {
+ res = PTR_ERR(tfm);
+ tfm = NULL;
+ goto out;
+ }
+ crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
+ req = skcipher_request_alloc(tfm, GFP_NOFS);
+ if (!req) {
+ res = -ENOMEM;
+ goto out;
+ }
+ skcipher_request_set_callback(req,
+ CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+ crypto_req_done, &wait);
+ res = crypto_skcipher_setkey(tfm, nonce, FS_KEY_DERIVATION_NONCE_SIZE);
+ if (res < 0)
+ goto out;
+
+ sg_init_one(&src_sg, master_key, derived_keysize);
+ sg_init_one(&dst_sg, derived_key, derived_keysize);
+ skcipher_request_set_crypt(req, &src_sg, &dst_sg, derived_keysize,
+ NULL);
+ res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
+out:
+ skcipher_request_free(req);
+ crypto_free_skcipher(tfm);
+ return res;
+}
+
+/*
+ * Search the current task's subscribed keyrings for a "logon" key with
+ * description prefix:descriptor, and if found acquire a read lock on it and
+ * return a pointer to its validated payload in *payload_ret.
+ */
+static struct key *
+find_and_lock_process_key(const char *prefix,
+ const u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE],
+ unsigned int min_keysize,
+ const struct fscrypt_key **payload_ret)
+{
+ char *description;
+ struct key *key;
+ const struct user_key_payload *ukp;
+ const struct fscrypt_key *payload;
+
+ description = kasprintf(GFP_NOFS, "%s%*phN", prefix,
+ FSCRYPT_KEY_DESCRIPTOR_SIZE, descriptor);
+ if (!description)
+ return ERR_PTR(-ENOMEM);
+
+ key = request_key(&key_type_logon, description, NULL);
+ kfree(description);
+ if (IS_ERR(key))
+ return key;
+
+ down_read(&key->sem);
+ ukp = user_key_payload_locked(key);
+
+ if (!ukp) /* was the key revoked before we acquired its semaphore? */
+ goto invalid;
+
+ payload = (const struct fscrypt_key *)ukp->data;
+
+ if (ukp->datalen != sizeof(struct fscrypt_key) ||
+ payload->size < 1 || payload->size > FSCRYPT_MAX_KEY_SIZE) {
+ fscrypt_warn(NULL,
+ "key with description '%s' has invalid payload",
+ key->description);
+ goto invalid;
+ }
+
+ if (payload->size < min_keysize) {
+ fscrypt_warn(NULL,
+ "key with description '%s' is too short (got %u bytes, need %u+ bytes)",
+ key->description, payload->size, min_keysize);
+ goto invalid;
+ }
+
+ *payload_ret = payload;
+ return key;
+
+invalid:
+ up_read(&key->sem);
+ key_put(key);
+ return ERR_PTR(-ENOKEY);
+}
+
+/* Master key referenced by DIRECT_KEY policy */
+struct fscrypt_direct_key {
+ struct hlist_node dk_node;
+ refcount_t dk_refcount;
+ const struct fscrypt_mode *dk_mode;
+ struct crypto_skcipher *dk_ctfm;
+ u8 dk_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
+ u8 dk_raw[FSCRYPT_MAX_KEY_SIZE];
+};
+
+static void free_direct_key(struct fscrypt_direct_key *dk)
+{
+ if (dk) {
+ crypto_free_skcipher(dk->dk_ctfm);
+ kzfree(dk);
+ }
+}
+
+void fscrypt_put_direct_key(struct fscrypt_direct_key *dk)
+{
+ if (!refcount_dec_and_lock(&dk->dk_refcount, &fscrypt_direct_keys_lock))
+ return;
+ hash_del(&dk->dk_node);
+ spin_unlock(&fscrypt_direct_keys_lock);
+
+ free_direct_key(dk);
+}
+
+/*
+ * Find/insert the given key into the fscrypt_direct_keys table. If found, it
+ * is returned with elevated refcount, and 'to_insert' is freed if non-NULL. If
+ * not found, 'to_insert' is inserted and returned if it's non-NULL; otherwise
+ * NULL is returned.
+ */
+static struct fscrypt_direct_key *
+find_or_insert_direct_key(struct fscrypt_direct_key *to_insert,
+ const u8 *raw_key, const struct fscrypt_info *ci)
+{
+ unsigned long hash_key;
+ struct fscrypt_direct_key *dk;
+
+ /*
+ * Careful: to avoid potentially leaking secret key bytes via timing
+ * information, we must key the hash table by descriptor rather than by
+ * raw key, and use crypto_memneq() when comparing raw keys.
+ */
+
+ BUILD_BUG_ON(sizeof(hash_key) > FSCRYPT_KEY_DESCRIPTOR_SIZE);
+ memcpy(&hash_key, ci->ci_policy.v1.master_key_descriptor,
+ sizeof(hash_key));
+
+ spin_lock(&fscrypt_direct_keys_lock);
+ hash_for_each_possible(fscrypt_direct_keys, dk, dk_node, hash_key) {
+ if (memcmp(ci->ci_policy.v1.master_key_descriptor,
+ dk->dk_descriptor, FSCRYPT_KEY_DESCRIPTOR_SIZE) != 0)
+ continue;
+ if (ci->ci_mode != dk->dk_mode)
+ continue;
+ if (crypto_memneq(raw_key, dk->dk_raw, ci->ci_mode->keysize))
+ continue;
+ /* using existing tfm with same (descriptor, mode, raw_key) */
+ refcount_inc(&dk->dk_refcount);
+ spin_unlock(&fscrypt_direct_keys_lock);
+ free_direct_key(to_insert);
+ return dk;
+ }
+ if (to_insert)
+ hash_add(fscrypt_direct_keys, &to_insert->dk_node, hash_key);
+ spin_unlock(&fscrypt_direct_keys_lock);
+ return to_insert;
+}
+
+/* Prepare to encrypt directly using the master key in the given mode */
+static struct fscrypt_direct_key *
+fscrypt_get_direct_key(const struct fscrypt_info *ci, const u8 *raw_key)
+{
+ struct fscrypt_direct_key *dk;
+ int err;
+
+ /* Is there already a tfm for this key? */
+ dk = find_or_insert_direct_key(NULL, raw_key, ci);
+ if (dk)
+ return dk;
+
+ /* Nope, allocate one. */
+ dk = kzalloc(sizeof(*dk), GFP_NOFS);
+ if (!dk)
+ return ERR_PTR(-ENOMEM);
+ refcount_set(&dk->dk_refcount, 1);
+ dk->dk_mode = ci->ci_mode;
+ dk->dk_ctfm = fscrypt_allocate_skcipher(ci->ci_mode, raw_key,
+ ci->ci_inode);
+ if (IS_ERR(dk->dk_ctfm)) {
+ err = PTR_ERR(dk->dk_ctfm);
+ dk->dk_ctfm = NULL;
+ goto err_free_dk;
+ }
+ memcpy(dk->dk_descriptor, ci->ci_policy.v1.master_key_descriptor,
+ FSCRYPT_KEY_DESCRIPTOR_SIZE);
+ memcpy(dk->dk_raw, raw_key, ci->ci_mode->keysize);
+
+ return find_or_insert_direct_key(dk, raw_key, ci);
+
+err_free_dk:
+ free_direct_key(dk);
+ return ERR_PTR(err);
+}
+
+/* v1 policy, DIRECT_KEY: use the master key directly */
+static int setup_v1_file_key_direct(struct fscrypt_info *ci,
+ const u8 *raw_master_key)
+{
+ const struct fscrypt_mode *mode = ci->ci_mode;
+ struct fscrypt_direct_key *dk;
+
+ if (!fscrypt_mode_supports_direct_key(mode)) {
+ fscrypt_warn(ci->ci_inode,
+ "Direct key mode not allowed with %s",
+ mode->friendly_name);
+ return -EINVAL;
+ }
+
+ if (ci->ci_policy.v1.contents_encryption_mode !=
+ ci->ci_policy.v1.filenames_encryption_mode) {
+ fscrypt_warn(ci->ci_inode,
+ "Direct key mode not allowed with different contents and filenames modes");
+ return -EINVAL;
+ }
+
+ /* ESSIV implies 16-byte IVs which implies !DIRECT_KEY */
+ if (WARN_ON(mode->needs_essiv))
+ return -EINVAL;
+
+ dk = fscrypt_get_direct_key(ci, raw_master_key);
+ if (IS_ERR(dk))
+ return PTR_ERR(dk);
+ ci->ci_direct_key = dk;
+ ci->ci_ctfm = dk->dk_ctfm;
+ return 0;
+}
+
+/* v1 policy, !DIRECT_KEY: derive the file's encryption key */
+static int setup_v1_file_key_derived(struct fscrypt_info *ci,
+ const u8 *raw_master_key)
+{
+ u8 *derived_key;
+ int err;
+
+ /*
+ * This cannot be a stack buffer because it will be passed to the
+ * scatterlist crypto API during derive_key_aes().
+ */
+ derived_key = kmalloc(ci->ci_mode->keysize, GFP_NOFS);
+ if (!derived_key)
+ return -ENOMEM;
+
+ err = derive_key_aes(raw_master_key, ci->ci_nonce,
+ derived_key, ci->ci_mode->keysize);
+ if (err)
+ goto out;
+
+ err = fscrypt_set_derived_key(ci, derived_key);
+out:
+ kzfree(derived_key);
+ return err;
+}
+
+int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, const u8 *raw_master_key)
+{
+ if (ci->ci_policy.v1.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY)
+ return setup_v1_file_key_direct(ci, raw_master_key);
+ else
+ return setup_v1_file_key_derived(ci, raw_master_key);
+}
+
+int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci)
+{
+ struct key *key;
+ const struct fscrypt_key *payload;
+ int err;
+
+ key = find_and_lock_process_key(FSCRYPT_KEY_DESC_PREFIX,
+ ci->ci_policy.v1.master_key_descriptor,
+ ci->ci_mode->keysize, &payload);
+ if (key == ERR_PTR(-ENOKEY) && ci->ci_inode->i_sb->s_cop->key_prefix) {
+ key = find_and_lock_process_key(ci->ci_inode->i_sb->s_cop->key_prefix,
+ ci->ci_policy.v1.master_key_descriptor,
+ ci->ci_mode->keysize, &payload);
+ }
+ if (IS_ERR(key))
+ return PTR_ERR(key);
+
+ err = fscrypt_setup_v1_file_key(ci, payload->raw);
+ up_read(&key->sem);
+ key_put(key);
+ return err;
+}
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 4941fe8471ce..4072ba644595 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -5,8 +5,9 @@
* Copyright (C) 2015, Google, Inc.
* Copyright (C) 2015, Motorola Mobility.
*
- * Written by Michael Halcrow, 2015.
+ * Originally written by Michael Halcrow, 2015.
* Modified by Jaegeuk Kim, 2015.
+ * Modified by Eric Biggers, 2019 for v2 policy support.
*/
#include <linux/random.h>
@@ -14,70 +15,303 @@
#include <linux/mount.h>
#include "fscrypt_private.h"
-/*
- * check whether an encryption policy is consistent with an encryption context
+/**
+ * fscrypt_policies_equal - check whether two encryption policies are the same
+ *
+ * Return: %true if equal, else %false
+ */
+bool fscrypt_policies_equal(const union fscrypt_policy *policy1,
+ const union fscrypt_policy *policy2)
+{
+ if (policy1->version != policy2->version)
+ return false;
+
+ return !memcmp(policy1, policy2, fscrypt_policy_size(policy1));
+}
+
+/**
+ * fscrypt_supported_policy - check whether an encryption policy is supported
+ *
+ * Given an encryption policy, check whether all its encryption modes and other
+ * settings are supported by this kernel. (But we don't currently don't check
+ * for crypto API support here, so attempting to use an algorithm not configured
+ * into the crypto API will still fail later.)
+ *
+ * Return: %true if supported, else %false
+ */
+bool fscrypt_supported_policy(const union fscrypt_policy *policy_u,
+ const struct inode *inode)
+{
+ switch (policy_u->version) {
+ case FSCRYPT_POLICY_V1: {
+ const struct fscrypt_policy_v1 *policy = &policy_u->v1;
+
+ if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
+ policy->filenames_encryption_mode)) {
+ fscrypt_warn(inode,
+ "Unsupported encryption modes (contents %d, filenames %d)",
+ policy->contents_encryption_mode,
+ policy->filenames_encryption_mode);
+ return false;
+ }
+
+ if (policy->flags & ~FSCRYPT_POLICY_FLAGS_VALID) {
+ fscrypt_warn(inode,
+ "Unsupported encryption flags (0x%02x)",
+ policy->flags);
+ return false;
+ }
+
+ return true;
+ }
+ case FSCRYPT_POLICY_V2: {
+ const struct fscrypt_policy_v2 *policy = &policy_u->v2;
+
+ if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
+ policy->filenames_encryption_mode)) {
+ fscrypt_warn(inode,
+ "Unsupported encryption modes (contents %d, filenames %d)",
+ policy->contents_encryption_mode,
+ policy->filenames_encryption_mode);
+ return false;
+ }
+
+ if (policy->flags & ~FSCRYPT_POLICY_FLAGS_VALID) {
+ fscrypt_warn(inode,
+ "Unsupported encryption flags (0x%02x)",
+ policy->flags);
+ return false;
+ }
+
+ if (memchr_inv(policy->__reserved, 0,
+ sizeof(policy->__reserved))) {
+ fscrypt_warn(inode,
+ "Reserved bits set in encryption policy");
+ return false;
+ }
+
+ return true;
+ }
+ }
+ return false;
+}
+
+/**
+ * fscrypt_new_context_from_policy - create a new fscrypt_context from a policy
+ *
+ * Create an fscrypt_context for an inode that is being assigned the given
+ * encryption policy. A new nonce is randomly generated.
+ *
+ * Return: the size of the new context in bytes.
*/
-static bool is_encryption_context_consistent_with_policy(
- const struct fscrypt_context *ctx,
- const struct fscrypt_policy *policy)
+static int fscrypt_new_context_from_policy(union fscrypt_context *ctx_u,
+ const union fscrypt_policy *policy_u)
{
- return memcmp(ctx->master_key_descriptor, policy->master_key_descriptor,
- FS_KEY_DESCRIPTOR_SIZE) == 0 &&
- (ctx->flags == policy->flags) &&
- (ctx->contents_encryption_mode ==
- policy->contents_encryption_mode) &&
- (ctx->filenames_encryption_mode ==
- policy->filenames_encryption_mode);
+ memset(ctx_u, 0, sizeof(*ctx_u));
+
+ switch (policy_u->version) {
+ case FSCRYPT_POLICY_V1: {
+ const struct fscrypt_policy_v1 *policy = &policy_u->v1;
+ struct fscrypt_context_v1 *ctx = &ctx_u->v1;
+
+ ctx->version = FSCRYPT_CONTEXT_V1;
+ ctx->contents_encryption_mode =
+ policy->contents_encryption_mode;
+ ctx->filenames_encryption_mode =
+ policy->filenames_encryption_mode;
+ ctx->flags = policy->flags;
+ memcpy(ctx->master_key_descriptor,
+ policy->master_key_descriptor,
+ sizeof(ctx->master_key_descriptor));
+ get_random_bytes(ctx->nonce, sizeof(ctx->nonce));
+ return sizeof(*ctx);
+ }
+ case FSCRYPT_POLICY_V2: {
+ const struct fscrypt_policy_v2 *policy = &policy_u->v2;
+ struct fscrypt_context_v2 *ctx = &ctx_u->v2;
+
+ ctx->version = FSCRYPT_CONTEXT_V2;
+ ctx->contents_encryption_mode =
+ policy->contents_encryption_mode;
+ ctx->filenames_encryption_mode =
+ policy->filenames_encryption_mode;
+ ctx->flags = policy->flags;
+ memcpy(ctx->master_key_identifier,
+ policy->master_key_identifier,
+ sizeof(ctx->master_key_identifier));
+ get_random_bytes(ctx->nonce, sizeof(ctx->nonce));
+ return sizeof(*ctx);
+ }
+ }
+ BUG();
}
-static int create_encryption_context_from_policy(struct inode *inode,
- const struct fscrypt_policy *policy)
+/**
+ * fscrypt_policy_from_context - convert an fscrypt_context to an fscrypt_policy
+ *
+ * Given an fscrypt_context, build the corresponding fscrypt_policy.
+ *
+ * Return: 0 on success, or -EINVAL if the fscrypt_context has an unrecognized
+ * version number or size.
+ *
+ * This does *not* validate the settings within the policy itself, e.g. the
+ * modes, flags, and reserved bits. Use fscrypt_supported_policy() for that.
+ */
+int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
+ const union fscrypt_context *ctx_u,
+ int ctx_size)
{
- struct fscrypt_context ctx;
+ memset(policy_u, 0, sizeof(*policy_u));
+
+ if (ctx_size <= 0 || ctx_size != fscrypt_context_size(ctx_u))
+ return -EINVAL;
+
+ switch (ctx_u->version) {
+ case FSCRYPT_CONTEXT_V1: {
+ const struct fscrypt_context_v1 *ctx = &ctx_u->v1;
+ struct fscrypt_policy_v1 *policy = &policy_u->v1;
+
+ policy->version = FSCRYPT_POLICY_V1;
+ policy->contents_encryption_mode =
+ ctx->contents_encryption_mode;
+ policy->filenames_encryption_mode =
+ ctx->filenames_encryption_mode;
+ policy->flags = ctx->flags;
+ memcpy(policy->master_key_descriptor,
+ ctx->master_key_descriptor,
+ sizeof(policy->master_key_descriptor));
+ return 0;
+ }
+ case FSCRYPT_CONTEXT_V2: {
+ const struct fscrypt_context_v2 *ctx = &ctx_u->v2;
+ struct fscrypt_policy_v2 *policy = &policy_u->v2;
+
+ policy->version = FSCRYPT_POLICY_V2;
+ policy->contents_encryption_mode =
+ ctx->contents_encryption_mode;
+ policy->filenames_encryption_mode =
+ ctx->filenames_encryption_mode;
+ policy->flags = ctx->flags;
+ memcpy(policy->__reserved, ctx->__reserved,
+ sizeof(policy->__reserved));
+ memcpy(policy->master_key_identifier,
+ ctx->master_key_identifier,
+ sizeof(policy->master_key_identifier));
+ return 0;
+ }
+ }
+ /* unreachable */
+ return -EINVAL;
+}
+
+/* Retrieve an inode's encryption policy */
+static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy)
+{
+ const struct fscrypt_info *ci;
+ union fscrypt_context ctx;
+ int ret;
+
+ ci = READ_ONCE(inode->i_crypt_info);
+ if (ci) {
+ /* key available, use the cached policy */
+ *policy = ci->ci_policy;
+ return 0;
+ }
+
+ if (!IS_ENCRYPTED(inode))
+ return -ENODATA;
- ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
- memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
- FS_KEY_DESCRIPTOR_SIZE);
+ ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
+ if (ret < 0)
+ return (ret == -ERANGE) ? -EINVAL : ret;
- if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
- policy->filenames_encryption_mode))
+ return fscrypt_policy_from_context(policy, &ctx, ret);
+}
+
+static int set_encryption_policy(struct inode *inode,
+ const union fscrypt_policy *policy)
+{
+ union fscrypt_context ctx;
+ int ctxsize;
+ int err;
+
+ if (!fscrypt_supported_policy(policy, inode))
return -EINVAL;
- if (policy->flags & ~FS_POLICY_FLAGS_VALID)
+ switch (policy->version) {
+ case FSCRYPT_POLICY_V1:
+ /*
+ * The original encryption policy version provided no way of
+ * verifying that the correct master key was supplied, which was
+ * insecure in scenarios where multiple users have access to the
+ * same encrypted files (even just read-only access). The new
+ * encryption policy version fixes this and also implies use of
+ * an improved key derivation function and allows non-root users
+ * to securely remove keys. So as long as compatibility with
+ * old kernels isn't required, it is recommended to use the new
+ * policy version for all new encrypted directories.
+ */
+ pr_warn_once("%s (pid %d) is setting deprecated v1 encryption policy; recommend upgrading to v2.\n",
+ current->comm, current->pid);
+ break;
+ case FSCRYPT_POLICY_V2:
+ err = fscrypt_verify_key_added(inode->i_sb,
+ policy->v2.master_key_identifier);
+ if (err)
+ return err;
+ break;
+ default:
+ WARN_ON(1);
return -EINVAL;
+ }
- ctx.contents_encryption_mode = policy->contents_encryption_mode;
- ctx.filenames_encryption_mode = policy->filenames_encryption_mode;
- ctx.flags = policy->flags;
- BUILD_BUG_ON(sizeof(ctx.nonce) != FS_KEY_DERIVATION_NONCE_SIZE);
- get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
+ ctxsize = fscrypt_new_context_from_policy(&ctx, policy);
- return inode->i_sb->s_cop->set_context(inode, &ctx, sizeof(ctx), NULL);
+ return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, NULL);
}
int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
{
- struct fscrypt_policy policy;
+ union fscrypt_policy policy;
+ union fscrypt_policy existing_policy;
struct inode *inode = file_inode(filp);
+ u8 version;
+ int size;
int ret;
- struct fscrypt_context ctx;
- if (copy_from_user(&policy, arg, sizeof(policy)))
+ if (get_user(policy.version, (const u8 __user *)arg))
return -EFAULT;
+ size = fscrypt_policy_size(&policy);
+ if (size <= 0)
+ return -EINVAL;
+
+ /*
+ * We should just copy the remaining 'size - 1' bytes here, but a
+ * bizarre bug in gcc 7 and earlier (fixed by gcc r255731) causes gcc to
+ * think that size can be 0 here (despite the check above!) *and* that
+ * it's a compile-time constant. Thus it would think copy_from_user()
+ * is passed compile-time constant ULONG_MAX, causing the compile-time
+ * buffer overflow check to fail, breaking the build. This only occurred
+ * when building an i386 kernel with -Os and branch profiling enabled.
+ *
+ * Work around it by just copying the first byte again...
+ */
+ version = policy.version;
+ if (copy_from_user(&policy, arg, size))
+ return -EFAULT;
+ policy.version = version;
+
if (!inode_owner_or_capable(inode))
return -EACCES;
- if (policy.version != 0)
- return -EINVAL;
-
ret = mnt_want_write_file(filp);
if (ret)
return ret;
inode_lock(inode);
- ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
+ ret = fscrypt_get_policy(inode, &existing_policy);
if (ret == -ENODATA) {
if (!S_ISDIR(inode->i_mode))
ret = -ENOTDIR;
@@ -86,14 +320,10 @@ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
else if (!inode->i_sb->s_cop->empty_dir(inode))
ret = -ENOTEMPTY;
else
- ret = create_encryption_context_from_policy(inode,
- &policy);
- } else if (ret == sizeof(ctx) &&
- is_encryption_context_consistent_with_policy(&ctx,
- &policy)) {
- /* The file already uses the same encryption policy. */
- ret = 0;
- } else if (ret >= 0 || ret == -ERANGE) {
+ ret = set_encryption_policy(inode, &policy);
+ } else if (ret == -EINVAL ||
+ (ret == 0 && !fscrypt_policies_equal(&policy,
+ &existing_policy))) {
/* The file already uses a different encryption policy. */
ret = -EEXIST;
}
@@ -105,37 +335,57 @@ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
}
EXPORT_SYMBOL(fscrypt_ioctl_set_policy);
+/* Original ioctl version; can only get the original policy version */
int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
{
- struct inode *inode = file_inode(filp);
- struct fscrypt_context ctx;
- struct fscrypt_policy policy;
- int res;
+ union fscrypt_policy policy;
+ int err;
- if (!IS_ENCRYPTED(inode))
- return -ENODATA;
+ err = fscrypt_get_policy(file_inode(filp), &policy);
+ if (err)
+ return err;
- res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
- if (res < 0 && res != -ERANGE)
- return res;
- if (res != sizeof(ctx))
- return -EINVAL;
- if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
+ if (policy.version != FSCRYPT_POLICY_V1)
return -EINVAL;
- policy.version = 0;
- policy.contents_encryption_mode = ctx.contents_encryption_mode;
- policy.filenames_encryption_mode = ctx.filenames_encryption_mode;
- policy.flags = ctx.flags;
- memcpy(policy.master_key_descriptor, ctx.master_key_descriptor,
- FS_KEY_DESCRIPTOR_SIZE);
-
- if (copy_to_user(arg, &policy, sizeof(policy)))
+ if (copy_to_user(arg, &policy, sizeof(policy.v1)))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL(fscrypt_ioctl_get_policy);
+/* Extended ioctl version; can get policies of any version */
+int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *uarg)
+{
+ struct fscrypt_get_policy_ex_arg arg;
+ union fscrypt_policy *policy = (union fscrypt_policy *)&arg.policy;
+ size_t policy_size;
+ int err;
+
+ /* arg is policy_size, then policy */
+ BUILD_BUG_ON(offsetof(typeof(arg), policy_size) != 0);
+ BUILD_BUG_ON(offsetofend(typeof(arg), policy_size) !=
+ offsetof(typeof(arg), policy));
+ BUILD_BUG_ON(sizeof(arg.policy) != sizeof(*policy));
+
+ err = fscrypt_get_policy(file_inode(filp), policy);
+ if (err)
+ return err;
+ policy_size = fscrypt_policy_size(policy);
+
+ if (copy_from_user(&arg, uarg, sizeof(arg.policy_size)))
+ return -EFAULT;
+
+ if (policy_size > arg.policy_size)
+ return -EOVERFLOW;
+ arg.policy_size = policy_size;
+
+ if (copy_to_user(uarg, &arg, sizeof(arg.policy_size) + policy_size))
+ return -EFAULT;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_policy_ex);
+
/**
* fscrypt_has_permitted_context() - is a file's encryption policy permitted
* within its directory?
@@ -157,10 +407,8 @@ EXPORT_SYMBOL(fscrypt_ioctl_get_policy);
*/
int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
{
- const struct fscrypt_operations *cops = parent->i_sb->s_cop;
- const struct fscrypt_info *parent_ci, *child_ci;
- struct fscrypt_context parent_ctx, child_ctx;
- int res;
+ union fscrypt_policy parent_policy, child_policy;
+ int err;
/* No restrictions on file types which are never encrypted */
if (!S_ISREG(child->i_mode) && !S_ISDIR(child->i_mode) &&
@@ -190,41 +438,22 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
* In any case, if an unexpected error occurs, fall back to "forbidden".
*/
- res = fscrypt_get_encryption_info(parent);
- if (res)
+ err = fscrypt_get_encryption_info(parent);
+ if (err)
return 0;
- res = fscrypt_get_encryption_info(child);
- if (res)
+ err = fscrypt_get_encryption_info(child);
+ if (err)
return 0;
- parent_ci = READ_ONCE(parent->i_crypt_info);
- child_ci = READ_ONCE(child->i_crypt_info);
-
- if (parent_ci && child_ci) {
- return memcmp(parent_ci->ci_master_key_descriptor,
- child_ci->ci_master_key_descriptor,
- FS_KEY_DESCRIPTOR_SIZE) == 0 &&
- (parent_ci->ci_data_mode == child_ci->ci_data_mode) &&
- (parent_ci->ci_filename_mode ==
- child_ci->ci_filename_mode) &&
- (parent_ci->ci_flags == child_ci->ci_flags);
- }
- res = cops->get_context(parent, &parent_ctx, sizeof(parent_ctx));
- if (res != sizeof(parent_ctx))
+ err = fscrypt_get_policy(parent, &parent_policy);
+ if (err)
return 0;
- res = cops->get_context(child, &child_ctx, sizeof(child_ctx));
- if (res != sizeof(child_ctx))
+ err = fscrypt_get_policy(child, &child_policy);
+ if (err)
return 0;
- return memcmp(parent_ctx.master_key_descriptor,
- child_ctx.master_key_descriptor,
- FS_KEY_DESCRIPTOR_SIZE) == 0 &&
- (parent_ctx.contents_encryption_mode ==
- child_ctx.contents_encryption_mode) &&
- (parent_ctx.filenames_encryption_mode ==
- child_ctx.filenames_encryption_mode) &&
- (parent_ctx.flags == child_ctx.flags);
+ return fscrypt_policies_equal(&parent_policy, &child_policy);
}
EXPORT_SYMBOL(fscrypt_has_permitted_context);
@@ -240,7 +469,8 @@ EXPORT_SYMBOL(fscrypt_has_permitted_context);
int fscrypt_inherit_context(struct inode *parent, struct inode *child,
void *fs_data, bool preload)
{
- struct fscrypt_context ctx;
+ union fscrypt_context ctx;
+ int ctxsize;
struct fscrypt_info *ci;
int res;
@@ -252,16 +482,10 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child,
if (ci == NULL)
return -ENOKEY;
- ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
- ctx.contents_encryption_mode = ci->ci_data_mode;
- ctx.filenames_encryption_mode = ci->ci_filename_mode;
- ctx.flags = ci->ci_flags;
- memcpy(ctx.master_key_descriptor, ci->ci_master_key_descriptor,
- FS_KEY_DESCRIPTOR_SIZE);
- get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
+ ctxsize = fscrypt_new_context_from_policy(&ctx, &ci->ci_policy);
+
BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE);
- res = parent->i_sb->s_cop->set_context(child, &ctx,
- sizeof(ctx), fs_data);
+ res = parent->i_sb->s_cop->set_context(child, &ctx, ctxsize, fs_data);
if (res)
return res;
return preload ? fscrypt_get_encryption_info(child): 0;
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 442f7ef873fc..5703d607f5af 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -1113,8 +1113,35 @@ resizefs_out:
#endif
}
case EXT4_IOC_GET_ENCRYPTION_POLICY:
+ if (!ext4_has_feature_encrypt(sb))
+ return -EOPNOTSUPP;
return fscrypt_ioctl_get_policy(filp, (void __user *)arg);
+ case FS_IOC_GET_ENCRYPTION_POLICY_EX:
+ if (!ext4_has_feature_encrypt(sb))
+ return -EOPNOTSUPP;
+ return fscrypt_ioctl_get_policy_ex(filp, (void __user *)arg);
+
+ case FS_IOC_ADD_ENCRYPTION_KEY:
+ if (!ext4_has_feature_encrypt(sb))
+ return -EOPNOTSUPP;
+ return fscrypt_ioctl_add_key(filp, (void __user *)arg);
+
+ case FS_IOC_REMOVE_ENCRYPTION_KEY:
+ if (!ext4_has_feature_encrypt(sb))
+ return -EOPNOTSUPP;
+ return fscrypt_ioctl_remove_key(filp, (void __user *)arg);
+
+ case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
+ if (!ext4_has_feature_encrypt(sb))
+ return -EOPNOTSUPP;
+ return fscrypt_ioctl_remove_key_all_users(filp,
+ (void __user *)arg);
+ case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
+ if (!ext4_has_feature_encrypt(sb))
+ return -EOPNOTSUPP;
+ return fscrypt_ioctl_get_key_status(filp, (void __user *)arg);
+
case EXT4_IOC_FSGETXATTR:
{
struct fsxattr fa;
@@ -1231,6 +1258,11 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case EXT4_IOC_SET_ENCRYPTION_POLICY:
case EXT4_IOC_GET_ENCRYPTION_PWSALT:
case EXT4_IOC_GET_ENCRYPTION_POLICY:
+ case FS_IOC_GET_ENCRYPTION_POLICY_EX:
+ case FS_IOC_ADD_ENCRYPTION_KEY:
+ case FS_IOC_REMOVE_ENCRYPTION_KEY:
+ case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
+ case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
case EXT4_IOC_SHUTDOWN:
case FS_IOC_GETFSMAP:
break;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 4079605d437a..757819139b8f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1107,6 +1107,9 @@ static int ext4_drop_inode(struct inode *inode)
{
int drop = generic_drop_inode(inode);
+ if (!drop)
+ drop = fscrypt_drop_inode(inode);
+
trace_ext4_drop_inode(inode, drop);
return drop;
}
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 3e58a6f697dd..6a7349f9ac15 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2184,6 +2184,49 @@ out_err:
return err;
}
+static int f2fs_ioc_get_encryption_policy_ex(struct file *filp,
+ unsigned long arg)
+{
+ if (!f2fs_sb_has_encrypt(F2FS_I_SB(file_inode(filp))))
+ return -EOPNOTSUPP;
+
+ return fscrypt_ioctl_get_policy_ex(filp, (void __user *)arg);
+}
+
+static int f2fs_ioc_add_encryption_key(struct file *filp, unsigned long arg)
+{
+ if (!f2fs_sb_has_encrypt(F2FS_I_SB(file_inode(filp))))
+ return -EOPNOTSUPP;
+
+ return fscrypt_ioctl_add_key(filp, (void __user *)arg);
+}
+
+static int f2fs_ioc_remove_encryption_key(struct file *filp, unsigned long arg)
+{
+ if (!f2fs_sb_has_encrypt(F2FS_I_SB(file_inode(filp))))
+ return -EOPNOTSUPP;
+
+ return fscrypt_ioctl_remove_key(filp, (void __user *)arg);
+}
+
+static int f2fs_ioc_remove_encryption_key_all_users(struct file *filp,
+ unsigned long arg)
+{
+ if (!f2fs_sb_has_encrypt(F2FS_I_SB(file_inode(filp))))
+ return -EOPNOTSUPP;
+
+ return fscrypt_ioctl_remove_key_all_users(filp, (void __user *)arg);
+}
+
+static int f2fs_ioc_get_encryption_key_status(struct file *filp,
+ unsigned long arg)
+{
+ if (!f2fs_sb_has_encrypt(F2FS_I_SB(file_inode(filp))))
+ return -EOPNOTSUPP;
+
+ return fscrypt_ioctl_get_key_status(filp, (void __user *)arg);
+}
+
static int f2fs_ioc_gc(struct file *filp, unsigned long arg)
{
struct inode *inode = file_inode(filp);
@@ -3092,6 +3135,16 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return f2fs_ioc_get_encryption_policy(filp, arg);
case F2FS_IOC_GET_ENCRYPTION_PWSALT:
return f2fs_ioc_get_encryption_pwsalt(filp, arg);
+ case FS_IOC_GET_ENCRYPTION_POLICY_EX:
+ return f2fs_ioc_get_encryption_policy_ex(filp, arg);
+ case FS_IOC_ADD_ENCRYPTION_KEY:
+ return f2fs_ioc_add_encryption_key(filp, arg);
+ case FS_IOC_REMOVE_ENCRYPTION_KEY:
+ return f2fs_ioc_remove_encryption_key(filp, arg);
+ case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
+ return f2fs_ioc_remove_encryption_key_all_users(filp, arg);
+ case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
+ return f2fs_ioc_get_encryption_key_status(filp, arg);
case F2FS_IOC_GARBAGE_COLLECT:
return f2fs_ioc_gc(filp, arg);
case F2FS_IOC_GARBAGE_COLLECT_RANGE:
@@ -3219,6 +3272,11 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case F2FS_IOC_SET_ENCRYPTION_POLICY:
case F2FS_IOC_GET_ENCRYPTION_PWSALT:
case F2FS_IOC_GET_ENCRYPTION_POLICY:
+ case FS_IOC_GET_ENCRYPTION_POLICY_EX:
+ case FS_IOC_ADD_ENCRYPTION_KEY:
+ case FS_IOC_REMOVE_ENCRYPTION_KEY:
+ case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
+ case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
case F2FS_IOC_GARBAGE_COLLECT:
case F2FS_IOC_GARBAGE_COLLECT_RANGE:
case F2FS_IOC_WRITE_CHECKPOINT:
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 78a1b873e48a..e15bd29bd453 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -913,6 +913,8 @@ static int f2fs_drop_inode(struct inode *inode)
return 0;
}
ret = generic_drop_inode(inode);
+ if (!ret)
+ ret = fscrypt_drop_inode(inode);
trace_f2fs_drop_inode(inode, ret);
return ret;
}
diff --git a/fs/super.c b/fs/super.c
index da223b4cfbca..9459ba75a32e 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -32,6 +32,7 @@
#include <linux/backing-dev.h>
#include <linux/rculist_bl.h>
#include <linux/cleancache.h>
+#include <linux/fscrypt.h>
#include <linux/fsnotify.h>
#include <linux/lockdep.h>
#include <linux/user_namespace.h>
@@ -290,6 +291,7 @@ static void __put_super(struct super_block *s)
WARN_ON(s->s_inode_lru.node);
WARN_ON(!list_empty(&s->s_mounts));
security_sb_free(s);
+ fscrypt_sb_free(s);
put_user_ns(s->s_user_ns);
kfree(s->s_subtype);
call_rcu(&s->rcu, destroy_super_rcu);
diff --git a/fs/ubifs/ioctl.c b/fs/ubifs/ioctl.c
index 034ad14710d1..5dc5abca11c7 100644
--- a/fs/ubifs/ioctl.c
+++ b/fs/ubifs/ioctl.c
@@ -185,6 +185,21 @@ long ubifs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case FS_IOC_GET_ENCRYPTION_POLICY:
return fscrypt_ioctl_get_policy(file, (void __user *)arg);
+ case FS_IOC_GET_ENCRYPTION_POLICY_EX:
+ return fscrypt_ioctl_get_policy_ex(file, (void __user *)arg);
+
+ case FS_IOC_ADD_ENCRYPTION_KEY:
+ return fscrypt_ioctl_add_key(file, (void __user *)arg);
+
+ case FS_IOC_REMOVE_ENCRYPTION_KEY:
+ return fscrypt_ioctl_remove_key(file, (void __user *)arg);
+
+ case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
+ return fscrypt_ioctl_remove_key_all_users(file,
+ (void __user *)arg);
+ case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
+ return fscrypt_ioctl_get_key_status(file, (void __user *)arg);
+
default:
return -ENOTTY;
}
@@ -202,6 +217,11 @@ long ubifs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
break;
case FS_IOC_SET_ENCRYPTION_POLICY:
case FS_IOC_GET_ENCRYPTION_POLICY:
+ case FS_IOC_GET_ENCRYPTION_POLICY_EX:
+ case FS_IOC_ADD_ENCRYPTION_KEY:
+ case FS_IOC_REMOVE_ENCRYPTION_KEY:
+ case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
+ case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
break;
default:
return -ENOIOCTLCMD;
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 8c1d571334bc..5e1e8ec0589e 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -318,6 +318,16 @@ static int ubifs_write_inode(struct inode *inode, struct writeback_control *wbc)
return err;
}
+static int ubifs_drop_inode(struct inode *inode)
+{
+ int drop = generic_drop_inode(inode);
+
+ if (!drop)
+ drop = fscrypt_drop_inode(inode);
+
+ return drop;
+}
+
static void ubifs_evict_inode(struct inode *inode)
{
int err;
@@ -1994,6 +2004,7 @@ const struct super_operations ubifs_super_operations = {
.free_inode = ubifs_free_inode,
.put_super = ubifs_put_super,
.write_inode = ubifs_write_inode,
+ .drop_inode = ubifs_drop_inode,
.evict_inode = ubifs_evict_inode,
.statfs = ubifs_statfs,
.dirty_inode = ubifs_dirty_inode,