[PATCH v2 1/6] fscrypt: Don't use asynchronous CryptoAPI algorithms

[Eric Biggers <ebiggers@kernel.org>]

Now that fscrypt's incomplete support for non-inline crypto engines has
been removed, and none of the CPU-based algorithms have the
CRYPTO_ALG_ASYNC flag set anymore, there is no need to accommodate
asynchronous algorithms.  Therefore, explicitly allocate only
synchronous algorithms.  Then, remove the code that handled waiting for
asynchronous en/decryption operations to complete.

This commit should *not* be backported to kernels that lack commit
0ba6ec5b2972 ("crypto: x86/aes - stop using the SIMD helper"), as then
it would disable the use of the optimized AES code on x86.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 fs/crypto/crypto.c          |  7 +++----
 fs/crypto/fname.c           | 18 ++++++++----------
 fs/crypto/fscrypt_private.h |  5 +++--
 fs/crypto/keysetup_v1.c     |  9 ++++-----
 4 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index ddf6991d46da2..43d1658e07cec 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -113,11 +113,10 @@ int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci,
 			    unsigned int len, unsigned int offs,
 			    gfp_t gfp_flags)
 {
 	union fscrypt_iv iv;
 	struct skcipher_request *req = NULL;
-	DECLARE_CRYPTO_WAIT(wait);
 	struct scatterlist dst, src;
 	struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
 	int res = 0;
 
 	if (WARN_ON_ONCE(len <= 0))
@@ -131,21 +130,21 @@ int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci,
 	if (!req)
 		return -ENOMEM;
 
 	skcipher_request_set_callback(
 		req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
-		crypto_req_done, &wait);
+		NULL, NULL);
 
 	sg_init_table(&dst, 1);
 	sg_set_page(&dst, dest_page, len, offs);
 	sg_init_table(&src, 1);
 	sg_set_page(&src, src_page, len, offs);
 	skcipher_request_set_crypt(req, &src, &dst, len, &iv);
 	if (rw == FS_DECRYPT)
-		res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait);
+		res = crypto_skcipher_decrypt(req);
 	else
-		res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
+		res = crypto_skcipher_encrypt(req);
 	skcipher_request_free(req);
 	if (res) {
 		fscrypt_err(ci->ci_inode,
 			    "%scryption failed for data unit %llu: %d",
 			    (rw == FS_DECRYPT ? "De" : "En"), index, res);
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index fb01dde0f2e55..17edc24ccd42f 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -93,11 +93,10 @@ static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
  */
 int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
 			  u8 *out, unsigned int olen)
 {
 	struct skcipher_request *req = NULL;
-	DECLARE_CRYPTO_WAIT(wait);
 	const struct fscrypt_inode_info *ci = inode->i_crypt_info;
 	struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
 	union fscrypt_iv iv;
 	struct scatterlist sg;
 	int res;
@@ -116,18 +115,18 @@ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
 
 	/* Set up the encryption request */
 	req = skcipher_request_alloc(tfm, GFP_NOFS);
 	if (!req)
 		return -ENOMEM;
-	skcipher_request_set_callback(req,
-			CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
-			crypto_req_done, &wait);
+	skcipher_request_set_callback(
+		req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+		NULL, NULL);
 	sg_init_one(&sg, out, olen);
 	skcipher_request_set_crypt(req, &sg, &sg, olen, &iv);
 
 	/* Do the encryption */
-	res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
+	res = crypto_skcipher_encrypt(req);
 	skcipher_request_free(req);
 	if (res < 0) {
 		fscrypt_err(inode, "Filename encryption failed: %d", res);
 		return res;
 	}
@@ -149,33 +148,32 @@ EXPORT_SYMBOL_GPL(fscrypt_fname_encrypt);
 static int fname_decrypt(const struct inode *inode,
 			 const struct fscrypt_str *iname,
 			 struct fscrypt_str *oname)
 {
 	struct skcipher_request *req = NULL;
-	DECLARE_CRYPTO_WAIT(wait);
 	struct scatterlist src_sg, dst_sg;
 	const struct fscrypt_inode_info *ci = inode->i_crypt_info;
 	struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
 	union fscrypt_iv iv;
 	int res;
 
 	/* Allocate request */
 	req = skcipher_request_alloc(tfm, GFP_NOFS);
 	if (!req)
 		return -ENOMEM;
-	skcipher_request_set_callback(req,
-		CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
-		crypto_req_done, &wait);
+	skcipher_request_set_callback(
+		req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+		NULL, NULL);
 
 	/* Initialize IV */
 	fscrypt_generate_iv(&iv, 0, ci);
 
 	/* Create decryption request */
 	sg_init_one(&src_sg, iname->name, iname->len);
 	sg_init_one(&dst_sg, oname->name, oname->len);
 	skcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, &iv);
-	res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait);
+	res = crypto_skcipher_decrypt(req);
 	skcipher_request_free(req);
 	if (res < 0) {
 		fscrypt_err(inode, "Filename decryption failed: %d", res);
 		return res;
 	}
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 6e7164530a1e2..06fa8f2b2d081 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -57,12 +57,13 @@
  * Adiantum is faster still, and is the recommended option on such platforms...)
  *
  * Note that fscrypt also supports inline crypto engines.  Those don't use the
  * Crypto API and work much better than the old-style (non-inline) engines.
  */
-#define FSCRYPT_CRYPTOAPI_MASK \
-	(CRYPTO_ALG_ALLOCATES_MEMORY | CRYPTO_ALG_KERN_DRIVER_ONLY)
+#define FSCRYPT_CRYPTOAPI_MASK                            \
+	(CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY | \
+	 CRYPTO_ALG_KERN_DRIVER_ONLY)
 
 #define FSCRYPT_CONTEXT_V1	1
 #define FSCRYPT_CONTEXT_V2	2
 
 /* Keep this in sync with include/uapi/linux/fscrypt.h */
diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c
index 158ceae8a5bce..3fdf174384f3d 100644
--- a/fs/crypto/keysetup_v1.c
+++ b/fs/crypto/keysetup_v1.c
@@ -48,11 +48,10 @@ static int derive_key_aes(const u8 *master_key,
 			  const u8 nonce[FSCRYPT_FILE_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, FSCRYPT_CRYPTOAPI_MASK);
 
 	if (IS_ERR(tfm)) {
@@ -64,22 +63,22 @@ static int derive_key_aes(const u8 *master_key,
 	req = skcipher_request_alloc(tfm, GFP_KERNEL);
 	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);
+	skcipher_request_set_callback(
+		req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+		NULL, NULL);
 	res = crypto_skcipher_setkey(tfm, nonce, FSCRYPT_FILE_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);
+	res = crypto_skcipher_encrypt(req);
 out:
 	skcipher_request_free(req);
 	crypto_free_skcipher(tfm);
 	return res;
 }
-- 
2.50.1