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

Pull fscrypt updates from Eric Biggers:
 "This release, we add support for inline encryption via the blk-crypto
  framework which was added in 5.8.

  Now when an ext4 or f2fs filesystem is mounted with '-o inlinecrypt',
  the contents of encrypted files will be encrypted/decrypted via
  blk-crypto, instead of directly using the crypto API. This model
  allows taking advantage of the inline encryption hardware that is
  integrated into the UFS or eMMC host controllers on most mobile SoCs.

  Note that this is just an alternate implementation; the ciphertext
  written to disk stays the same.

  (This pull request does *not* include support for direct I/O on
  encrypted files, which blk-crypto makes possible, since that part is
  still being discussed.)

  Besides the above feature update, there are also a few fixes and
  cleanups, e.g. strengthening some memory barriers that may be too
  weak.

  All these patches have been in linux-next with no reported issues.
  I've also tested them with the fscrypt xfstests, as usual. It's also
  been tested that the inline encryption support works with the support
  for Qualcomm and Mediatek inline encryption hardware that will be in
  the scsi pull request for 5.9. Also, several SoC vendors are already
  using a previous, functionally equivalent version of these patches"

* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt:
  fscrypt: don't load ->i_crypt_info before it's known to be valid
  fscrypt: document inline encryption support
  fscrypt: use smp_load_acquire() for ->i_crypt_info
  fscrypt: use smp_load_acquire() for ->s_master_keys
  fscrypt: use smp_load_acquire() for fscrypt_prepared_key
  fscrypt: switch fscrypt_do_sha256() to use the SHA-256 library
  fscrypt: restrict IV_INO_LBLK_* to AES-256-XTS
  fscrypt: rename FS_KEY_DERIVATION_NONCE_SIZE
  fscrypt: add comments that describe the HKDF info strings
  ext4: add inline encryption support
  f2fs: add inline encryption support
  fscrypt: add inline encryption support
  fs: introduce SB_INLINECRYPT

1 files changed, 121 insertions, 23 deletions

diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index eb7fcd2b7fb8..8117a61b6f55 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -14,12 +14,13 @@
 #include <linux/fscrypt.h>
 #include <linux/siphash.h>
 #include <crypto/hash.h>
+#include <linux/blk-crypto.h>
 
 #define CONST_STRLEN(str)	(sizeof(str) - 1)
 
-#define FS_KEY_DERIVATION_NONCE_SIZE	16
+#define FSCRYPT_FILE_NONCE_SIZE	16
 
-#define FSCRYPT_MIN_KEY_SIZE		16
+#define FSCRYPT_MIN_KEY_SIZE	16
 
 #define FSCRYPT_CONTEXT_V1	1
 #define FSCRYPT_CONTEXT_V2	2
@@ -30,7 +31,7 @@ struct fscrypt_context_v1 {
 	u8 filenames_encryption_mode;
 	u8 flags;
 	u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
-	u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+	u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
 };
 
 struct fscrypt_context_v2 {
@@ -40,7 +41,7 @@ struct fscrypt_context_v2 {
 	u8 flags;
 	u8 __reserved[4];
 	u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
-	u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+	u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
 };
 
 /*
@@ -166,6 +167,20 @@ struct fscrypt_symlink_data {
 	char encrypted_path[1];
 } __packed;
 
+/**
+ * struct fscrypt_prepared_key - a key prepared for actual encryption/decryption
+ * @tfm: crypto API transform object
+ * @blk_key: key for blk-crypto
+ *
+ * Normally only one of the fields will be non-NULL.
+ */
+struct fscrypt_prepared_key {
+	struct crypto_skcipher *tfm;
+#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
+	struct fscrypt_blk_crypto_key *blk_key;
+#endif
+};
+
 /*
  * fscrypt_info - the "encryption key" for an inode
  *
@@ -175,12 +190,20 @@ struct fscrypt_symlink_data {
  */
 struct fscrypt_info {
 
-	/* The actual crypto transform used for encryption and decryption */
-	struct crypto_skcipher *ci_ctfm;
+	/* The key in a form prepared for actual encryption/decryption */
+	struct fscrypt_prepared_key ci_enc_key;
 
-	/* True if the key should be freed when this fscrypt_info is freed */
+	/* True if ci_enc_key should be freed when this fscrypt_info is freed */
 	bool ci_owns_key;
 
+#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
+	/*
+	 * True if this inode will use inline encryption (blk-crypto) instead of
+	 * the traditional filesystem-layer encryption.
+	 */
+	bool ci_inlinecrypt;
+#endif
+
 	/*
 	 * Encryption mode used for this inode.  It corresponds to either the
 	 * contents or filenames encryption mode, depending on the inode type.
@@ -205,7 +228,7 @@ struct fscrypt_info {
 
 	/*
 	 * If non-NULL, then encryption is done using the master key directly
-	 * and ci_ctfm will equal ci_direct_key->dk_ctfm.
+	 * and ci_enc_key will equal ci_direct_key->dk_key.
 	 */
 	struct fscrypt_direct_key *ci_direct_key;
 
@@ -221,7 +244,7 @@ struct fscrypt_info {
 	union fscrypt_policy ci_policy;
 
 	/* This inode's nonce, copied from the fscrypt_context */
-	u8 ci_nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+	u8 ci_nonce[FSCRYPT_FILE_NONCE_SIZE];
 
 	/* Hashed inode number.  Only set for IV_INO_LBLK_32 */
 	u32 ci_hashed_ino;
@@ -257,9 +280,10 @@ union fscrypt_iv {
 		__le64 lblk_num;
 
 		/* per-file nonce; only set in DIRECT_KEY mode */
-		u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+		u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
 	};
 	u8 raw[FSCRYPT_MAX_IV_SIZE];
+	__le64 dun[FSCRYPT_MAX_IV_SIZE / sizeof(__le64)];
 };
 
 void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num,
@@ -288,13 +312,13 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key,
  * 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_ENC_KEY	2
-#define HKDF_CONTEXT_DIRECT_KEY		3
-#define HKDF_CONTEXT_IV_INO_LBLK_64_KEY	4
-#define HKDF_CONTEXT_DIRHASH_KEY	5
-#define HKDF_CONTEXT_IV_INO_LBLK_32_KEY	6
-#define HKDF_CONTEXT_INODE_HASH_KEY	7
+#define HKDF_CONTEXT_KEY_IDENTIFIER	1 /* info=<empty>		*/
+#define HKDF_CONTEXT_PER_FILE_ENC_KEY	2 /* info=file_nonce		*/
+#define HKDF_CONTEXT_DIRECT_KEY		3 /* info=mode_num		*/
+#define HKDF_CONTEXT_IV_INO_LBLK_64_KEY	4 /* info=mode_num||fs_uuid	*/
+#define HKDF_CONTEXT_DIRHASH_KEY	5 /* info=file_nonce		*/
+#define HKDF_CONTEXT_IV_INO_LBLK_32_KEY	6 /* info=mode_num||fs_uuid	*/
+#define HKDF_CONTEXT_INODE_HASH_KEY	7 /* info=<empty>		*/
 
 int fscrypt_hkdf_expand(const struct fscrypt_hkdf *hkdf, u8 context,
 			const u8 *info, unsigned int infolen,
@@ -302,6 +326,78 @@ int fscrypt_hkdf_expand(const struct fscrypt_hkdf *hkdf, u8 context,
 
 void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf);
 
+/* inline_crypt.c */
+#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
+int fscrypt_select_encryption_impl(struct fscrypt_info *ci);
+
+static inline bool
+fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
+{
+	return ci->ci_inlinecrypt;
+}
+
+int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
+				     const u8 *raw_key,
+				     const struct fscrypt_info *ci);
+
+void fscrypt_destroy_inline_crypt_key(struct fscrypt_prepared_key *prep_key);
+
+/*
+ * Check whether the crypto transform or blk-crypto key has been allocated in
+ * @prep_key, depending on which encryption implementation the file will use.
+ */
+static inline bool
+fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
+			const struct fscrypt_info *ci)
+{
+	/*
+	 * The two smp_load_acquire()'s here pair with the smp_store_release()'s
+	 * in fscrypt_prepare_inline_crypt_key() and fscrypt_prepare_key().
+	 * I.e., in some cases (namely, if this prep_key is a per-mode
+	 * encryption key) another task can publish blk_key or tfm concurrently,
+	 * executing a RELEASE barrier.  We need to use smp_load_acquire() here
+	 * to safely ACQUIRE the memory the other task published.
+	 */
+	if (fscrypt_using_inline_encryption(ci))
+		return smp_load_acquire(&prep_key->blk_key) != NULL;
+	return smp_load_acquire(&prep_key->tfm) != NULL;
+}
+
+#else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
+
+static inline int fscrypt_select_encryption_impl(struct fscrypt_info *ci)
+{
+	return 0;
+}
+
+static inline bool
+fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
+{
+	return false;
+}
+
+static inline int
+fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
+				 const u8 *raw_key,
+				 const struct fscrypt_info *ci)
+{
+	WARN_ON(1);
+	return -EOPNOTSUPP;
+}
+
+static inline void
+fscrypt_destroy_inline_crypt_key(struct fscrypt_prepared_key *prep_key)
+{
+}
+
+static inline bool
+fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
+			const struct fscrypt_info *ci)
+{
+	return smp_load_acquire(&prep_key->tfm) != NULL;
+}
+#endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
+
 /* keyring.c */
 
 /*
@@ -395,9 +491,9 @@ struct fscrypt_master_key {
 	 * Per-mode encryption keys for the various types of encryption policies
 	 * that use them.  Allocated and derived on-demand.
 	 */
-	struct crypto_skcipher *mk_direct_keys[__FSCRYPT_MODE_MAX + 1];
-	struct crypto_skcipher *mk_iv_ino_lblk_64_keys[__FSCRYPT_MODE_MAX + 1];
-	struct crypto_skcipher *mk_iv_ino_lblk_32_keys[__FSCRYPT_MODE_MAX + 1];
+	struct fscrypt_prepared_key mk_direct_keys[__FSCRYPT_MODE_MAX + 1];
+	struct fscrypt_prepared_key mk_iv_ino_lblk_64_keys[__FSCRYPT_MODE_MAX + 1];
+	struct fscrypt_prepared_key mk_iv_ino_lblk_32_keys[__FSCRYPT_MODE_MAX + 1];
 
 	/* Hash key for inode numbers.  Initialized only when needed. */
 	siphash_key_t		mk_ino_hash_key;
@@ -461,13 +557,15 @@ struct fscrypt_mode {
 	int keysize;
 	int ivsize;
 	int logged_impl_name;
+	enum blk_crypto_mode_num blk_crypto_mode;
 };
 
 extern struct fscrypt_mode fscrypt_modes[];
 
-struct crypto_skcipher *fscrypt_allocate_skcipher(struct fscrypt_mode *mode,
-						  const u8 *raw_key,
-						  const struct inode *inode);
+int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key,
+			const u8 *raw_key, const struct fscrypt_info *ci);
+
+void fscrypt_destroy_prepared_key(struct fscrypt_prepared_key *prep_key);
 
 int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key);