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

Pull fscrypt updates from Eric Biggers:
 "The main change this cycle is a significant simplification that's been
  overdue for a while now: standardizing on a single file contents
  encryption implementation in ext4 and f2fs, instead of having two.

  Specifically, the original filesystem-layer file contents encryption
  implementation is removed, and the blk-crypto implementation is now
  used unconditionally. blk-crypto delegates either to inline crypto
  hardware or to the CPU via blk-crypto-fallback. The latter is
  functionally equivalent to the original filesystem-layer code.

  The blk-crypto implementation already existed, but previously it was
  used only when the filesystem was mounted with "-o inlinecrypt". Now,
  "-o inlinecrypt" just selects whether inline crypto hardware is used.

  To allow maintaining that user control over hardware use, the
  blk-crypto API is extended with a new flag BLK_CRYPTO_CFG_ALLOW_HW.

  Overall, this removes quite a bit of redundant code from ext4, f2fs,
  and fs/crypto/. It should make things easier for ongoing filesystem
  efforts such as iomap support, large folios, and btrfs encryption
  (btrfs had already been planning to use blk-crypto exclusively.)

  There are two small behavior changes of note:

   - Direct I/O now works on encrypted files even without "-o inlinecrypt",
     rather than falling back to buffered I/O. This is effectively a
     bugfix, though I'll continue to keep an eye out for any user that
     may have been depending on the buffered I/O fallback.

   - IV_INO_LBLK_32 policies are no longer supported in certain cases
     that didn't make sense and have no known uses.

  This has been in linux-next since July 22 with no reported issues. All
  encryption xfstests pass on ext4 and f2fs. As usual I've also been
  using it on a system with an fscrypt-encrypted home directory. Of
  course, the blk-crypto code paths also aren't new and were already
  being used on many systems via the inlinecrypt mount option.

  In addition to the main change described above, there are a few other
  cleanups such as using lock guards for mutexes, improving
  documentation, and removing a workaround for outdated gcc versions"

* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux: (29 commits)
  blk-crypto: Update docs for blk-crypto-fallback motivation
  blk-crypto: Remove unused function blk_crypto_config_supported()
  fscrypt: Update docs for data path
  fscrypt: Remove unused function fscrypt_finalize_bounce_page()
  f2fs: Update outdated comment in f2fs_write_begin()
  fs: Update outdated comment for SB_INLINECRYPT
  fscrypt: Update encryption policy version docs
  fscrypt: Replace some variable-size memsets with fixed-size
  fscrypt: Add safety checks to non-block-based en/decryption
  fscrypt: Merge bio.c and inline_crypt.c into block.c
  fscrypt: Remove unused functions and workqueue
  fscrypt: Remove fs-layer zeroout code
  fscrypt: Remove fscrypt_dio_supported()
  fscrypt: Replace calls to fscrypt_inode_uses_inline_crypto()
  fs/buffer: Remove fs-layer decryption code
  f2fs: Remove fs-layer file contents en/decryption code
  ext4: Further de-generalize the bio postprocessing code
  ext4: Make ext4_bio_write_folio() return void
  ext4: Remove fs-layer file contents en/decryption code
  Documentation: fscrypt: Update docs for inlinecrypt
  ...

4 files changed, 31 insertions, 43 deletions

diff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c
index 2a5c52ab74b4..2a8f40a65158 100644
--- a/block/blk-crypto-fallback.c
+++ b/block/blk-crypto-fallback.c
@@ -496,8 +496,7 @@ bool blk_crypto_fallback_bio_prep(struct bio *bio)
 		return false;
 	}
 
-	if (!__blk_crypto_cfg_supported(blk_crypto_fallback_profile,
-					&bc->bc_key->crypto_cfg)) {
+	if (bc->bc_key->crypto_cfg.key_type != BLK_CRYPTO_KEY_TYPE_RAW) {
 		bio_endio_status(bio, BLK_STS_NOTSUPP);
 		return false;
 	}
diff --git a/block/blk-crypto-internal.h b/block/blk-crypto-internal.h
index 742694213529..2c7a0446572a 100644
--- a/block/blk-crypto-internal.h
+++ b/block/blk-crypto-internal.h
@@ -80,9 +80,6 @@ void blk_crypto_put_keyslot(struct blk_crypto_keyslot *slot);
 int __blk_crypto_evict_key(struct blk_crypto_profile *profile,
 			   const struct blk_crypto_key *key);
 
-bool __blk_crypto_cfg_supported(struct blk_crypto_profile *profile,
-				const struct blk_crypto_config *cfg);
-
 int blk_crypto_ioctl(struct block_device *bdev, unsigned int cmd,
 		     void __user *argp);
 
diff --git a/block/blk-crypto-profile.c b/block/blk-crypto-profile.c
index cf447ba4a66e..53126c091b0b 100644
--- a/block/blk-crypto-profile.c
+++ b/block/blk-crypto-profile.c
@@ -335,28 +335,6 @@ void blk_crypto_put_keyslot(struct blk_crypto_keyslot *slot)
 	}
 }
 
-/**
- * __blk_crypto_cfg_supported() - Check whether the given crypto profile
- *				  supports the given crypto configuration.
- * @profile: the crypto profile to check
- * @cfg: the crypto configuration to check for
- *
- * Return: %true if @profile supports the given @cfg.
- */
-bool __blk_crypto_cfg_supported(struct blk_crypto_profile *profile,
-				const struct blk_crypto_config *cfg)
-{
-	if (!profile)
-		return false;
-	if (!(profile->modes_supported[cfg->crypto_mode] & cfg->data_unit_size))
-		return false;
-	if (profile->max_dun_bytes_supported < cfg->dun_bytes)
-		return false;
-	if (!(profile->key_types_supported & cfg->key_type))
-		return false;
-	return true;
-}
-
 /*
  * This is an internal function that evicts a key from an inline encryption
  * device that can be either a real device or the blk-crypto-fallback "device".
diff --git a/block/blk-crypto.c b/block/blk-crypto.c
index 15e25e41b166..bc3a9f59574b 100644
--- a/block/blk-crypto.c
+++ b/block/blk-crypto.c
@@ -300,6 +300,7 @@ int __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
  * @dun_bytes: number of bytes that will be used to specify the DUN when this
  *	       key is used
  * @data_unit_size: the data unit size to use for en/decryption
+ * @flags: BLK_CRYPTO_CFG_* flags
  *
  * Return: 0 on success, -errno on failure.  The caller is responsible for
  *	   zeroizing both blk_key and key_bytes when done with them.
@@ -309,7 +310,7 @@ int blk_crypto_init_key(struct blk_crypto_key *blk_key,
 			enum blk_crypto_key_type key_type,
 			enum blk_crypto_mode_num crypto_mode,
 			unsigned int dun_bytes,
-			unsigned int data_unit_size)
+			unsigned int data_unit_size, int flags)
 {
 	const struct blk_crypto_mode *mode;
 
@@ -318,6 +319,9 @@ int blk_crypto_init_key(struct blk_crypto_key *blk_key,
 	if (crypto_mode >= ARRAY_SIZE(blk_crypto_modes))
 		return -EINVAL;
 
+	if (flags & ~BLK_CRYPTO_CFG_ALLOW_HW)
+		return -EINVAL;
+
 	mode = &blk_crypto_modes[crypto_mode];
 	switch (key_type) {
 	case BLK_CRYPTO_KEY_TYPE_RAW:
@@ -328,6 +332,8 @@ int blk_crypto_init_key(struct blk_crypto_key *blk_key,
 		if (key_size < mode->security_strength ||
 		    key_size > BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE)
 			return -EINVAL;
+		if (!(flags & BLK_CRYPTO_CFG_ALLOW_HW))
+			return -EINVAL;
 		break;
 	default:
 		return -EINVAL;
@@ -343,6 +349,7 @@ int blk_crypto_init_key(struct blk_crypto_key *blk_key,
 	blk_key->crypto_cfg.dun_bytes = dun_bytes;
 	blk_key->crypto_cfg.data_unit_size = data_unit_size;
 	blk_key->crypto_cfg.key_type = key_type;
+	blk_key->crypto_cfg.flags = flags;
 	blk_key->data_unit_size_bits = ilog2(data_unit_size);
 	blk_key->size = key_size;
 	memcpy(blk_key->bytes, key_bytes, key_size);
@@ -351,25 +358,32 @@ int blk_crypto_init_key(struct blk_crypto_key *blk_key,
 }
 EXPORT_SYMBOL_GPL(blk_crypto_init_key);
 
+/**
+ * blk_crypto_config_supported_natively() - Check whether a block device
+ *					    supports hardware inline encryption
+ *					    with the given configuration.
+ * @bdev: the block device
+ * @cfg: the crypto configuration to check for
+ *
+ * Return: %true if @bdev supports hardware inline encryption with @cfg.
+ */
 bool blk_crypto_config_supported_natively(struct block_device *bdev,
 					  const struct blk_crypto_config *cfg)
 {
-	return __blk_crypto_cfg_supported(bdev_get_queue(bdev)->crypto_profile,
-					  cfg);
-}
+	struct blk_crypto_profile *profile =
+		bdev_get_queue(bdev)->crypto_profile;
 
-/*
- * Check if bios with @cfg can be en/decrypted by blk-crypto (i.e. either the
- * block_device it's submitted to supports inline crypto, or the
- * blk-crypto-fallback is enabled and supports the cfg).
- */
-bool blk_crypto_config_supported(struct block_device *bdev,
-				 const struct blk_crypto_config *cfg)
-{
-	if (IS_ENABLED(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) &&
-	    cfg->key_type == BLK_CRYPTO_KEY_TYPE_RAW)
-		return true;
-	return blk_crypto_config_supported_natively(bdev, cfg);
+	if (!profile)
+		return false;
+	if (!(cfg->flags & BLK_CRYPTO_CFG_ALLOW_HW))
+		return false;
+	if (!(profile->modes_supported[cfg->crypto_mode] & cfg->data_unit_size))
+		return false;
+	if (profile->max_dun_bytes_supported < cfg->dun_bytes)
+		return false;
+	if (!(profile->key_types_supported & cfg->key_type))
+		return false;
+	return true;
 }
 
 /**