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-rw-r--r--fs/crypto/fscrypt_private.h4
-rw-r--r--fs/crypto/keyring.c64
-rw-r--r--fs/crypto/policy.c112
-rw-r--r--include/linux/fscrypt.h39
4 files changed, 151 insertions, 68 deletions
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 7c93325161b0..6b4c8094cc7b 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -545,8 +545,8 @@ struct key *
fscrypt_find_master_key(struct super_block *sb,
const struct fscrypt_key_specifier *mk_spec);
-int fscrypt_add_test_dummy_key(struct super_block *sb,
- struct fscrypt_key_specifier *key_spec);
+int fscrypt_get_test_dummy_key_identifier(
+ u8 key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]);
int fscrypt_verify_key_added(struct super_block *sb,
const u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]);
diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index 0b3ffbb4faf4..caee9f8620dd 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -688,28 +688,68 @@ out_wipe_secret:
}
EXPORT_SYMBOL_GPL(fscrypt_ioctl_add_key);
-/*
- * Add the key for '-o test_dummy_encryption' to the filesystem keyring.
- *
- * Use a per-boot random key to prevent people from misusing this option.
- */
-int fscrypt_add_test_dummy_key(struct super_block *sb,
- struct fscrypt_key_specifier *key_spec)
+static void
+fscrypt_get_test_dummy_secret(struct fscrypt_master_key_secret *secret)
{
static u8 test_key[FSCRYPT_MAX_KEY_SIZE];
+
+ get_random_once(test_key, FSCRYPT_MAX_KEY_SIZE);
+
+ memset(secret, 0, sizeof(*secret));
+ secret->size = FSCRYPT_MAX_KEY_SIZE;
+ memcpy(secret->raw, test_key, FSCRYPT_MAX_KEY_SIZE);
+}
+
+int fscrypt_get_test_dummy_key_identifier(
+ u8 key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE])
+{
struct fscrypt_master_key_secret secret;
int err;
- get_random_once(test_key, FSCRYPT_MAX_KEY_SIZE);
+ fscrypt_get_test_dummy_secret(&secret);
- memset(&secret, 0, sizeof(secret));
- secret.size = FSCRYPT_MAX_KEY_SIZE;
- memcpy(secret.raw, test_key, FSCRYPT_MAX_KEY_SIZE);
+ err = fscrypt_init_hkdf(&secret.hkdf, secret.raw, secret.size);
+ if (err)
+ goto out;
+ err = fscrypt_hkdf_expand(&secret.hkdf, HKDF_CONTEXT_KEY_IDENTIFIER,
+ NULL, 0, key_identifier,
+ FSCRYPT_KEY_IDENTIFIER_SIZE);
+out:
+ wipe_master_key_secret(&secret);
+ return err;
+}
+
+/**
+ * fscrypt_add_test_dummy_key() - add the test dummy encryption key
+ * @sb: the filesystem instance to add the key to
+ * @dummy_policy: the encryption policy for test_dummy_encryption
+ *
+ * If needed, add the key for the test_dummy_encryption mount option to the
+ * filesystem. To prevent misuse of this mount option, a per-boot random key is
+ * used instead of a hardcoded one. This makes it so that any encrypted files
+ * created using this option won't be accessible after a reboot.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int fscrypt_add_test_dummy_key(struct super_block *sb,
+ const struct fscrypt_dummy_policy *dummy_policy)
+{
+ const union fscrypt_policy *policy = dummy_policy->policy;
+ struct fscrypt_key_specifier key_spec;
+ struct fscrypt_master_key_secret secret;
+ int err;
- err = add_master_key(sb, &secret, key_spec);
+ if (!policy)
+ return 0;
+ err = fscrypt_policy_to_key_spec(policy, &key_spec);
+ if (err)
+ return err;
+ fscrypt_get_test_dummy_secret(&secret);
+ err = add_master_key(sb, &secret, &key_spec);
wipe_master_key_secret(&secret);
return err;
}
+EXPORT_SYMBOL_GPL(fscrypt_add_test_dummy_key);
/*
* Verify that the current user has added a master key with the given identifier
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 2a11276913a9..5f858cee1e3b 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -10,6 +10,7 @@
* Modified by Eric Biggers, 2019 for v2 policy support.
*/
+#include <linux/fs_context.h>
#include <linux/random.h>
#include <linux/seq_file.h>
#include <linux/string.h>
@@ -724,73 +725,45 @@ int fscrypt_set_context(struct inode *inode, void *fs_data)
EXPORT_SYMBOL_GPL(fscrypt_set_context);
/**
- * fscrypt_set_test_dummy_encryption() - handle '-o test_dummy_encryption'
- * @sb: the filesystem on which test_dummy_encryption is being specified
- * @arg: the argument to the test_dummy_encryption option. May be NULL.
- * @dummy_policy: the filesystem's current dummy policy (input/output, see
- * below)
+ * fscrypt_parse_test_dummy_encryption() - parse the test_dummy_encryption mount option
+ * @param: the mount option
+ * @dummy_policy: (input/output) the place to write the dummy policy that will
+ * result from parsing the option. Zero-initialize this. If a policy is
+ * already set here (due to test_dummy_encryption being given multiple
+ * times), then this function will verify that the policies are the same.
*
- * Handle the test_dummy_encryption mount option by creating a dummy encryption
- * policy, saving it in @dummy_policy, and adding the corresponding dummy
- * encryption key to the filesystem. If the @dummy_policy is already set, then
- * instead validate that it matches @arg. Don't support changing it via
- * remount, as that is difficult to do safely.
- *
- * Return: 0 on success (dummy policy set, or the same policy is already set);
- * -EEXIST if a different dummy policy is already set;
- * or another -errno value.
+ * Return: 0 on success; -EINVAL if the argument is invalid; -EEXIST if the
+ * argument conflicts with one already specified; or -ENOMEM.
*/
-int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg,
- struct fscrypt_dummy_policy *dummy_policy)
+int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
+ struct fscrypt_dummy_policy *dummy_policy)
{
- struct fscrypt_key_specifier key_spec = { 0 };
- int version;
- union fscrypt_policy *policy = NULL;
+ const char *arg = "v2";
+ union fscrypt_policy *policy;
int err;
- if (!arg)
- arg = "v2";
-
- if (!strcmp(arg, "v1")) {
- version = FSCRYPT_POLICY_V1;
- key_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;
- memset(key_spec.u.descriptor, 0x42,
- FSCRYPT_KEY_DESCRIPTOR_SIZE);
- } else if (!strcmp(arg, "v2")) {
- version = FSCRYPT_POLICY_V2;
- key_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
- /* key_spec.u.identifier gets filled in when adding the key */
- } else {
- err = -EINVAL;
- goto out;
- }
+ if (param->type == fs_value_is_string && *param->string)
+ arg = param->string;
policy = kzalloc(sizeof(*policy), GFP_KERNEL);
- if (!policy) {
- err = -ENOMEM;
- goto out;
- }
-
- err = fscrypt_add_test_dummy_key(sb, &key_spec);
- if (err)
- goto out;
+ if (!policy)
+ return -ENOMEM;
- policy->version = version;
- switch (policy->version) {
- case FSCRYPT_POLICY_V1:
+ if (!strcmp(arg, "v1")) {
+ policy->version = FSCRYPT_POLICY_V1;
policy->v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
policy->v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
- memcpy(policy->v1.master_key_descriptor, key_spec.u.descriptor,
+ memset(policy->v1.master_key_descriptor, 0x42,
FSCRYPT_KEY_DESCRIPTOR_SIZE);
- break;
- case FSCRYPT_POLICY_V2:
+ } else if (!strcmp(arg, "v2")) {
+ policy->version = FSCRYPT_POLICY_V2;
policy->v2.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
policy->v2.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
- memcpy(policy->v2.master_key_identifier, key_spec.u.identifier,
- FSCRYPT_KEY_IDENTIFIER_SIZE);
- break;
- default:
- WARN_ON(1);
+ err = fscrypt_get_test_dummy_key_identifier(
+ policy->v2.master_key_identifier);
+ if (err)
+ goto out;
+ } else {
err = -EINVAL;
goto out;
}
@@ -809,6 +782,37 @@ out:
kfree(policy);
return err;
}
+EXPORT_SYMBOL_GPL(fscrypt_parse_test_dummy_encryption);
+
+/**
+ * fscrypt_dummy_policies_equal() - check whether two dummy policies are equal
+ * @p1: the first test dummy policy (may be unset)
+ * @p2: the second test dummy policy (may be unset)
+ *
+ * Return: %true if the dummy policies are both set and equal, or both unset.
+ */
+bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
+ const struct fscrypt_dummy_policy *p2)
+{
+ if (!p1->policy && !p2->policy)
+ return true;
+ if (!p1->policy || !p2->policy)
+ return false;
+ return fscrypt_policies_equal(p1->policy, p2->policy);
+}
+EXPORT_SYMBOL_GPL(fscrypt_dummy_policies_equal);
+
+/* Deprecated, do not use */
+int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg,
+ struct fscrypt_dummy_policy *dummy_policy)
+{
+ struct fs_parameter param = {
+ .type = fs_value_is_string,
+ .string = arg ? (char *)arg : "",
+ };
+ return fscrypt_parse_test_dummy_encryption(&param, dummy_policy) ?:
+ fscrypt_add_test_dummy_key(sb, dummy_policy);
+}
EXPORT_SYMBOL_GPL(fscrypt_set_test_dummy_encryption);
/**
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index efc7f96e5e26..e60d57c99cb6 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -32,6 +32,7 @@
union fscrypt_policy;
struct fscrypt_info;
+struct fs_parameter;
struct seq_file;
struct fscrypt_str {
@@ -289,10 +290,19 @@ struct fscrypt_dummy_policy {
const union fscrypt_policy *policy;
};
+int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
+ struct fscrypt_dummy_policy *dummy_policy);
+bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
+ const struct fscrypt_dummy_policy *p2);
int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg,
struct fscrypt_dummy_policy *dummy_policy);
void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep,
struct super_block *sb);
+static inline bool
+fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy)
+{
+ return dummy_policy->policy != NULL;
+}
static inline void
fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
{
@@ -303,6 +313,8 @@ fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
/* keyring.c */
void fscrypt_sb_free(struct super_block *sb);
int fscrypt_ioctl_add_key(struct file *filp, void __user *arg);
+int fscrypt_add_test_dummy_key(struct super_block *sb,
+ const struct fscrypt_dummy_policy *dummy_policy);
int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg);
int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg);
int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
@@ -477,12 +489,32 @@ static inline int fscrypt_set_context(struct inode *inode, void *fs_data)
struct fscrypt_dummy_policy {
};
+static inline int
+fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
+ struct fscrypt_dummy_policy *dummy_policy)
+{
+ return -EINVAL;
+}
+
+static inline bool
+fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
+ const struct fscrypt_dummy_policy *p2)
+{
+ return true;
+}
+
static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq,
char sep,
struct super_block *sb)
{
}
+static inline bool
+fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy)
+{
+ return false;
+}
+
static inline void
fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
{
@@ -498,6 +530,13 @@ static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg)
return -EOPNOTSUPP;
}
+static inline int
+fscrypt_add_test_dummy_key(struct super_block *sb,
+ const struct fscrypt_dummy_policy *dummy_policy)
+{
+ return 0;
+}
+
static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg)
{
return -EOPNOTSUPP;
generated by cgit (git 2.34.1) at 2024-06-21 06:12:20 +0000