Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt

Pull fscrypt updates from Eric Biggers:
 "This is a large update to fs/crypto/ which includes:

   - Add ioctls that add/remove encryption keys to/from a
     filesystem-level keyring.

     These fix user-reported issues where e.g. an encrypted home
     directory can break NetworkManager, sshd, Docker, etc. because they
     don't get access to the needed keyring. These ioctls also provide a
     way to lock encrypted directories that doesn't use the
     vm.drop_caches sysctl, so is faster, more reliable, and doesn't
     always need root.

   - Add a new encryption policy version ("v2") which switches to a more
     standard, secure, and flexible key derivation function, and starts
     verifying that the correct key was supplied before using it.

     The key derivation improvement is needed for its own sake as well
     as for ongoing feature work for which the current way is too
     inflexible.

  Work is in progress to update both Android and the 'fscrypt' userspace
  tool to use both these features. (Working patches are available and
  just need to be reviewed+merged.) Chrome OS will likely use them too.

  This has also been tested on ext4, f2fs, and ubifs with xfstests --
  both the existing encryption tests, and the new tests for this. This
  has also been in linux-next since Aug 16 with no reported issues. I'm
  also using an fscrypt v2-encrypted home directory on my personal
  desktop"

* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt: (27 commits)
  ext4 crypto: fix to check feature status before get policy
  fscrypt: document the new ioctls and policy version
  ubifs: wire up new fscrypt ioctls
  f2fs: wire up new fscrypt ioctls
  ext4: wire up new fscrypt ioctls
  fscrypt: require that key be added when setting a v2 encryption policy
  fscrypt: add FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS ioctl
  fscrypt: allow unprivileged users to add/remove keys for v2 policies
  fscrypt: v2 encryption policy support
  fscrypt: add an HKDF-SHA512 implementation
  fscrypt: add FS_IOC_GET_ENCRYPTION_KEY_STATUS ioctl
  fscrypt: add FS_IOC_REMOVE_ENCRYPTION_KEY ioctl
  fscrypt: add FS_IOC_ADD_ENCRYPTION_KEY ioctl
  fscrypt: rename keyinfo.c to keysetup.c
  fscrypt: move v1 policy key setup to keysetup_v1.c
  fscrypt: refactor key setup code in preparation for v2 policies
  fscrypt: rename fscrypt_master_key to fscrypt_direct_key
  fscrypt: add ->ci_inode to fscrypt_info
  fscrypt: use FSCRYPT_* definitions, not FS_*
  fscrypt: use FSCRYPT_ prefix for uapi constants
  ...

4 files changed, 237 insertions, 54 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 997a530ff4e9..5dff77326cec 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1427,6 +1427,7 @@ struct super_block {
 	const struct xattr_handler **s_xattr;
 #ifdef CONFIG_FS_ENCRYPTION
 	const struct fscrypt_operations	*s_cop;
+	struct key		*s_master_keys; /* master crypto keys in use */
 #endif
 	struct hlist_bl_head	s_roots;	/* alternate root dentries for NFS */
 	struct list_head	s_mounts;	/* list of mounts; _not_ for fs use */
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index bd8f207a2fb6..f622f7460ed8 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -16,6 +16,7 @@
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
+#include <uapi/linux/fscrypt.h>
 
 #define FS_CRYPTO_BLOCK_SIZE		16
 
@@ -42,7 +43,7 @@ struct fscrypt_name {
 #define fname_len(p)		((p)->disk_name.len)
 
 /* Maximum value for the third parameter of fscrypt_operations.set_context(). */
-#define FSCRYPT_SET_CONTEXT_MAX_SIZE	28
+#define FSCRYPT_SET_CONTEXT_MAX_SIZE	40
 
 #ifdef CONFIG_FS_ENCRYPTION
 /*
@@ -134,13 +135,23 @@ extern void fscrypt_free_bounce_page(struct page *bounce_page);
 /* policy.c */
 extern int fscrypt_ioctl_set_policy(struct file *, const void __user *);
 extern int fscrypt_ioctl_get_policy(struct file *, void __user *);
+extern int fscrypt_ioctl_get_policy_ex(struct file *, void __user *);
 extern int fscrypt_has_permitted_context(struct inode *, struct inode *);
 extern int fscrypt_inherit_context(struct inode *, struct inode *,
 					void *, bool);
-/* keyinfo.c */
+/* keyring.c */
+extern void fscrypt_sb_free(struct super_block *sb);
+extern int fscrypt_ioctl_add_key(struct file *filp, void __user *arg);
+extern int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg);
+extern int fscrypt_ioctl_remove_key_all_users(struct file *filp,
+					      void __user *arg);
+extern int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
+
+/* keysetup.c */
 extern int fscrypt_get_encryption_info(struct inode *);
 extern void fscrypt_put_encryption_info(struct inode *);
 extern void fscrypt_free_inode(struct inode *);
+extern int fscrypt_drop_inode(struct inode *inode);
 
 /* fname.c */
 extern int fscrypt_setup_filename(struct inode *, const struct qstr *,
@@ -353,6 +364,12 @@ static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
 	return -EOPNOTSUPP;
 }
 
+static inline int fscrypt_ioctl_get_policy_ex(struct file *filp,
+					      void __user *arg)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline int fscrypt_has_permitted_context(struct inode *parent,
 						struct inode *child)
 {
@@ -366,7 +383,34 @@ static inline int fscrypt_inherit_context(struct inode *parent,
 	return -EOPNOTSUPP;
 }
 
-/* keyinfo.c */
+/* keyring.c */
+static inline void fscrypt_sb_free(struct super_block *sb)
+{
+}
+
+static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_ioctl_remove_key_all_users(struct file *filp,
+						     void __user *arg)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int fscrypt_ioctl_get_key_status(struct file *filp,
+					       void __user *arg)
+{
+	return -EOPNOTSUPP;
+}
+
+/* keysetup.c */
 static inline int fscrypt_get_encryption_info(struct inode *inode)
 {
 	return -EOPNOTSUPP;
@@ -381,6 +425,11 @@ static inline void fscrypt_free_inode(struct inode *inode)
 {
 }
 
+static inline int fscrypt_drop_inode(struct inode *inode)
+{
+	return 0;
+}
+
  /* fname.c */
 static inline int fscrypt_setup_filename(struct inode *dir,
 					 const struct qstr *iname,
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 59c71fa8c553..41bd84d25a98 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -13,6 +13,9 @@
 #include <linux/limits.h>
 #include <linux/ioctl.h>
 #include <linux/types.h>
+#ifndef __KERNEL__
+#include <linux/fscrypt.h>
+#endif
 
 /* Use of MS_* flags within the kernel is restricted to core mount(2) code. */
 #if !defined(__KERNEL__)
@@ -213,57 +216,6 @@ struct fsxattr {
 #define FS_IOC_SETFSLABEL		_IOW(0x94, 50, char[FSLABEL_MAX])
 
 /*
- * File system encryption support
- */
-/* Policy provided via an ioctl on the topmost directory */
-#define FS_KEY_DESCRIPTOR_SIZE	8
-
-#define FS_POLICY_FLAGS_PAD_4		0x00
-#define FS_POLICY_FLAGS_PAD_8		0x01
-#define FS_POLICY_FLAGS_PAD_16		0x02
-#define FS_POLICY_FLAGS_PAD_32		0x03
-#define FS_POLICY_FLAGS_PAD_MASK	0x03
-#define FS_POLICY_FLAG_DIRECT_KEY	0x04	/* use master key directly */
-#define FS_POLICY_FLAGS_VALID		0x07
-
-/* Encryption algorithms */
-#define FS_ENCRYPTION_MODE_INVALID		0
-#define FS_ENCRYPTION_MODE_AES_256_XTS		1
-#define FS_ENCRYPTION_MODE_AES_256_GCM		2
-#define FS_ENCRYPTION_MODE_AES_256_CBC		3
-#define FS_ENCRYPTION_MODE_AES_256_CTS		4
-#define FS_ENCRYPTION_MODE_AES_128_CBC		5
-#define FS_ENCRYPTION_MODE_AES_128_CTS		6
-#define FS_ENCRYPTION_MODE_SPECK128_256_XTS	7 /* Removed, do not use. */
-#define FS_ENCRYPTION_MODE_SPECK128_256_CTS	8 /* Removed, do not use. */
-#define FS_ENCRYPTION_MODE_ADIANTUM		9
-
-struct fscrypt_policy {
-	__u8 version;
-	__u8 contents_encryption_mode;
-	__u8 filenames_encryption_mode;
-	__u8 flags;
-	__u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
-};
-
-#define FS_IOC_SET_ENCRYPTION_POLICY	_IOR('f', 19, struct fscrypt_policy)
-#define FS_IOC_GET_ENCRYPTION_PWSALT	_IOW('f', 20, __u8[16])
-#define FS_IOC_GET_ENCRYPTION_POLICY	_IOW('f', 21, struct fscrypt_policy)
-
-/* Parameters for passing an encryption key into the kernel keyring */
-#define FS_KEY_DESC_PREFIX		"fscrypt:"
-#define FS_KEY_DESC_PREFIX_SIZE		8
-
-/* Structure that userspace passes to the kernel keyring */
-#define FS_MAX_KEY_SIZE			64
-
-struct fscrypt_key {
-	__u32 mode;
-	__u8 raw[FS_MAX_KEY_SIZE];
-	__u32 size;
-};
-
-/*
  * Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS)
  *
  * Note: for historical reasons, these flags were originally used and
diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h
new file mode 100644
index 000000000000..39ccfe9311c3
--- /dev/null
+++ b/include/uapi/linux/fscrypt.h
@@ -0,0 +1,181 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * fscrypt user API
+ *
+ * These ioctls can be used on filesystems that support fscrypt.  See the
+ * "User API" section of Documentation/filesystems/fscrypt.rst.
+ */
+#ifndef _UAPI_LINUX_FSCRYPT_H
+#define _UAPI_LINUX_FSCRYPT_H
+
+#include <linux/types.h>
+
+/* Encryption policy flags */
+#define FSCRYPT_POLICY_FLAGS_PAD_4		0x00
+#define FSCRYPT_POLICY_FLAGS_PAD_8		0x01
+#define FSCRYPT_POLICY_FLAGS_PAD_16		0x02
+#define FSCRYPT_POLICY_FLAGS_PAD_32		0x03
+#define FSCRYPT_POLICY_FLAGS_PAD_MASK		0x03
+#define FSCRYPT_POLICY_FLAG_DIRECT_KEY		0x04
+#define FSCRYPT_POLICY_FLAGS_VALID		0x07
+
+/* Encryption algorithms */
+#define FSCRYPT_MODE_AES_256_XTS		1
+#define FSCRYPT_MODE_AES_256_CTS		4
+#define FSCRYPT_MODE_AES_128_CBC		5
+#define FSCRYPT_MODE_AES_128_CTS		6
+#define FSCRYPT_MODE_ADIANTUM			9
+#define __FSCRYPT_MODE_MAX			9
+
+/*
+ * Legacy policy version; ad-hoc KDF and no key verification.
+ * For new encrypted directories, use fscrypt_policy_v2 instead.
+ *
+ * Careful: the .version field for this is actually 0, not 1.
+ */
+#define FSCRYPT_POLICY_V1		0
+#define FSCRYPT_KEY_DESCRIPTOR_SIZE	8
+struct fscrypt_policy_v1 {
+	__u8 version;
+	__u8 contents_encryption_mode;
+	__u8 filenames_encryption_mode;
+	__u8 flags;
+	__u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
+};
+#define fscrypt_policy	fscrypt_policy_v1
+
+/*
+ * Process-subscribed "logon" key description prefix and payload format.
+ * Deprecated; prefer FS_IOC_ADD_ENCRYPTION_KEY instead.
+ */
+#define FSCRYPT_KEY_DESC_PREFIX		"fscrypt:"
+#define FSCRYPT_KEY_DESC_PREFIX_SIZE	8
+#define FSCRYPT_MAX_KEY_SIZE		64
+struct fscrypt_key {
+	__u32 mode;
+	__u8 raw[FSCRYPT_MAX_KEY_SIZE];
+	__u32 size;
+};
+
+/*
+ * New policy version with HKDF and key verification (recommended).
+ */
+#define FSCRYPT_POLICY_V2		2
+#define FSCRYPT_KEY_IDENTIFIER_SIZE	16
+struct fscrypt_policy_v2 {
+	__u8 version;
+	__u8 contents_encryption_mode;
+	__u8 filenames_encryption_mode;
+	__u8 flags;
+	__u8 __reserved[4];
+	__u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
+};
+
+/* Struct passed to FS_IOC_GET_ENCRYPTION_POLICY_EX */
+struct fscrypt_get_policy_ex_arg {
+	__u64 policy_size; /* input/output */
+	union {
+		__u8 version;
+		struct fscrypt_policy_v1 v1;
+		struct fscrypt_policy_v2 v2;
+	} policy; /* output */
+};
+
+/*
+ * v1 policy keys are specified by an arbitrary 8-byte key "descriptor",
+ * matching fscrypt_policy_v1::master_key_descriptor.
+ */
+#define FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR	1
+
+/*
+ * v2 policy keys are specified by a 16-byte key "identifier" which the kernel
+ * calculates as a cryptographic hash of the key itself,
+ * matching fscrypt_policy_v2::master_key_identifier.
+ */
+#define FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER	2
+
+/*
+ * Specifies a key, either for v1 or v2 policies.  This doesn't contain the
+ * actual key itself; this is just the "name" of the key.
+ */
+struct fscrypt_key_specifier {
+	__u32 type;	/* one of FSCRYPT_KEY_SPEC_TYPE_* */
+	__u32 __reserved;
+	union {
+		__u8 __reserved[32]; /* reserve some extra space */
+		__u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
+		__u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
+	} u;
+};
+
+/* Struct passed to FS_IOC_ADD_ENCRYPTION_KEY */
+struct fscrypt_add_key_arg {
+	struct fscrypt_key_specifier key_spec;
+	__u32 raw_size;
+	__u32 __reserved[9];
+	__u8 raw[];
+};
+
+/* Struct passed to FS_IOC_REMOVE_ENCRYPTION_KEY */
+struct fscrypt_remove_key_arg {
+	struct fscrypt_key_specifier key_spec;
+#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY	0x00000001
+#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS	0x00000002
+	__u32 removal_status_flags;	/* output */
+	__u32 __reserved[5];
+};
+
+/* Struct passed to FS_IOC_GET_ENCRYPTION_KEY_STATUS */
+struct fscrypt_get_key_status_arg {
+	/* input */
+	struct fscrypt_key_specifier key_spec;
+	__u32 __reserved[6];
+
+	/* output */
+#define FSCRYPT_KEY_STATUS_ABSENT		1
+#define FSCRYPT_KEY_STATUS_PRESENT		2
+#define FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED	3
+	__u32 status;
+#define FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF   0x00000001
+	__u32 status_flags;
+	__u32 user_count;
+	__u32 __out_reserved[13];
+};
+
+#define FS_IOC_SET_ENCRYPTION_POLICY		_IOR('f', 19, struct fscrypt_policy)
+#define FS_IOC_GET_ENCRYPTION_PWSALT		_IOW('f', 20, __u8[16])
+#define FS_IOC_GET_ENCRYPTION_POLICY		_IOW('f', 21, struct fscrypt_policy)
+#define FS_IOC_GET_ENCRYPTION_POLICY_EX		_IOWR('f', 22, __u8[9]) /* size + version */
+#define FS_IOC_ADD_ENCRYPTION_KEY		_IOWR('f', 23, struct fscrypt_add_key_arg)
+#define FS_IOC_REMOVE_ENCRYPTION_KEY		_IOWR('f', 24, struct fscrypt_remove_key_arg)
+#define FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS	_IOWR('f', 25, struct fscrypt_remove_key_arg)
+#define FS_IOC_GET_ENCRYPTION_KEY_STATUS	_IOWR('f', 26, struct fscrypt_get_key_status_arg)
+
+/**********************************************************************/
+
+/* old names; don't add anything new here! */
+#ifndef __KERNEL__
+#define FS_KEY_DESCRIPTOR_SIZE		FSCRYPT_KEY_DESCRIPTOR_SIZE
+#define FS_POLICY_FLAGS_PAD_4		FSCRYPT_POLICY_FLAGS_PAD_4
+#define FS_POLICY_FLAGS_PAD_8		FSCRYPT_POLICY_FLAGS_PAD_8
+#define FS_POLICY_FLAGS_PAD_16		FSCRYPT_POLICY_FLAGS_PAD_16
+#define FS_POLICY_FLAGS_PAD_32		FSCRYPT_POLICY_FLAGS_PAD_32
+#define FS_POLICY_FLAGS_PAD_MASK	FSCRYPT_POLICY_FLAGS_PAD_MASK
+#define FS_POLICY_FLAG_DIRECT_KEY	FSCRYPT_POLICY_FLAG_DIRECT_KEY
+#define FS_POLICY_FLAGS_VALID		FSCRYPT_POLICY_FLAGS_VALID
+#define FS_ENCRYPTION_MODE_INVALID	0	/* never used */
+#define FS_ENCRYPTION_MODE_AES_256_XTS	FSCRYPT_MODE_AES_256_XTS
+#define FS_ENCRYPTION_MODE_AES_256_GCM	2	/* never used */
+#define FS_ENCRYPTION_MODE_AES_256_CBC	3	/* never used */
+#define FS_ENCRYPTION_MODE_AES_256_CTS	FSCRYPT_MODE_AES_256_CTS
+#define FS_ENCRYPTION_MODE_AES_128_CBC	FSCRYPT_MODE_AES_128_CBC
+#define FS_ENCRYPTION_MODE_AES_128_CTS	FSCRYPT_MODE_AES_128_CTS
+#define FS_ENCRYPTION_MODE_SPECK128_256_XTS	7	/* removed */
+#define FS_ENCRYPTION_MODE_SPECK128_256_CTS	8	/* removed */
+#define FS_ENCRYPTION_MODE_ADIANTUM	FSCRYPT_MODE_ADIANTUM
+#define FS_KEY_DESC_PREFIX		FSCRYPT_KEY_DESC_PREFIX
+#define FS_KEY_DESC_PREFIX_SIZE		FSCRYPT_KEY_DESC_PREFIX_SIZE
+#define FS_MAX_KEY_SIZE			FSCRYPT_MAX_KEY_SIZE
+#endif /* !__KERNEL__ */
+
+#endif /* _UAPI_LINUX_FSCRYPT_H */