[SRU][N][PATCH 5/8] crypto: authenc - use memcpy_sglist() instead of null skcipher
Massimiliano Pellizzer
massimiliano.pellizzer at canonical.com
Thu Apr 30 12:30:24 UTC 2026
From: Eric Biggers <ebiggers at google.com>
commit dbc4b1458e931e47198c3165ff5853bc1ad6bd7a upstream.
For copying data between two scatterlists, just use memcpy_sglist()
instead of the so-called "null skcipher". This is much simpler.
Signed-off-by: Eric Biggers <ebiggers at google.com>
Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
Signed-off-by: Eric Biggers <ebiggers at kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(cherry picked from commit 7bc058a9b82b066fa68d4bc8b8d2b61834609410 linux-6.12.y)
CVE-2026-31431
Signed-off-by: Massimiliano Pellizzer <massimiliano.pellizzer at canonical.com>
---
crypto/Kconfig | 1 -
crypto/authenc.c | 32 +-------------------------------
crypto/authencesn.c | 38 +++-----------------------------------
3 files changed, 4 insertions(+), 67 deletions(-)
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 4b6362105499..56a602956660 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -222,7 +222,6 @@ config CRYPTO_AUTHENC
select CRYPTO_SKCIPHER
select CRYPTO_MANAGER
select CRYPTO_HASH
- select CRYPTO_NULL
help
Authenc: Combined mode wrapper for IPsec.
diff --git a/crypto/authenc.c b/crypto/authenc.c
index d04068af9833..f1f7886bb34c 100644
--- a/crypto/authenc.c
+++ b/crypto/authenc.c
@@ -9,7 +9,6 @@
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <crypto/authenc.h>
-#include <crypto/null.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
@@ -28,7 +27,6 @@ struct authenc_instance_ctx {
struct crypto_authenc_ctx {
struct crypto_ahash *auth;
struct crypto_skcipher *enc;
- struct crypto_sync_skcipher *null;
};
struct authenc_request_ctx {
@@ -186,21 +184,6 @@ static void crypto_authenc_encrypt_done(void *data, int err)
authenc_request_complete(areq, err);
}
-static int crypto_authenc_copy_assoc(struct aead_request *req)
-{
- struct crypto_aead *authenc = crypto_aead_reqtfm(req);
- struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
- SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
-
- skcipher_request_set_sync_tfm(skreq, ctx->null);
- skcipher_request_set_callback(skreq, aead_request_flags(req),
- NULL, NULL);
- skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen,
- NULL);
-
- return crypto_skcipher_encrypt(skreq);
-}
-
static int crypto_authenc_encrypt(struct aead_request *req)
{
struct crypto_aead *authenc = crypto_aead_reqtfm(req);
@@ -219,10 +202,7 @@ static int crypto_authenc_encrypt(struct aead_request *req)
dst = src;
if (req->src != req->dst) {
- err = crypto_authenc_copy_assoc(req);
- if (err)
- return err;
-
+ memcpy_sglist(req->dst, req->src, req->assoclen);
dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen);
}
@@ -328,7 +308,6 @@ static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
struct crypto_ahash *auth;
struct crypto_skcipher *enc;
- struct crypto_sync_skcipher *null;
int err;
auth = crypto_spawn_ahash(&ictx->auth);
@@ -340,14 +319,8 @@ static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
if (IS_ERR(enc))
goto err_free_ahash;
- null = crypto_get_default_null_skcipher();
- err = PTR_ERR(null);
- if (IS_ERR(null))
- goto err_free_skcipher;
-
ctx->auth = auth;
ctx->enc = enc;
- ctx->null = null;
crypto_aead_set_reqsize(
tfm,
@@ -361,8 +334,6 @@ static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
return 0;
-err_free_skcipher:
- crypto_free_skcipher(enc);
err_free_ahash:
crypto_free_ahash(auth);
return err;
@@ -374,7 +345,6 @@ static void crypto_authenc_exit_tfm(struct crypto_aead *tfm)
crypto_free_ahash(ctx->auth);
crypto_free_skcipher(ctx->enc);
- crypto_put_default_null_skcipher();
}
static void crypto_authenc_free(struct aead_instance *inst)
diff --git a/crypto/authencesn.c b/crypto/authencesn.c
index e08032e80f18..a5fbb638d9d7 100644
--- a/crypto/authencesn.c
+++ b/crypto/authencesn.c
@@ -12,7 +12,6 @@
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <crypto/authenc.h>
-#include <crypto/null.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
@@ -31,7 +30,6 @@ struct crypto_authenc_esn_ctx {
unsigned int reqoff;
struct crypto_ahash *auth;
struct crypto_skcipher *enc;
- struct crypto_sync_skcipher *null;
};
struct authenc_esn_request_ctx {
@@ -158,20 +156,6 @@ static void crypto_authenc_esn_encrypt_done(void *data, int err)
authenc_esn_request_complete(areq, err);
}
-static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
-{
- struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
- struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
- SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
-
- skcipher_request_set_sync_tfm(skreq, ctx->null);
- skcipher_request_set_callback(skreq, aead_request_flags(req),
- NULL, NULL);
- skcipher_request_set_crypt(skreq, req->src, req->dst, len, NULL);
-
- return crypto_skcipher_encrypt(skreq);
-}
-
static int crypto_authenc_esn_encrypt(struct aead_request *req)
{
struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
@@ -193,10 +177,7 @@ static int crypto_authenc_esn_encrypt(struct aead_request *req)
dst = src;
if (req->src != req->dst) {
- err = crypto_authenc_esn_copy(req, assoclen);
- if (err)
- return err;
-
+ memcpy_sglist(req->dst, req->src, assoclen);
sg_init_table(areq_ctx->dst, 2);
dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
}
@@ -283,11 +264,8 @@ static int crypto_authenc_esn_decrypt(struct aead_request *req)
cryptlen -= authsize;
- if (req->src != dst) {
- err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
- if (err)
- return err;
- }
+ if (req->src != dst)
+ memcpy_sglist(dst, req->src, assoclen + cryptlen);
scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
authsize, 0);
@@ -323,7 +301,6 @@ static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
struct crypto_ahash *auth;
struct crypto_skcipher *enc;
- struct crypto_sync_skcipher *null;
int err;
auth = crypto_spawn_ahash(&ictx->auth);
@@ -335,14 +312,8 @@ static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
if (IS_ERR(enc))
goto err_free_ahash;
- null = crypto_get_default_null_skcipher();
- err = PTR_ERR(null);
- if (IS_ERR(null))
- goto err_free_skcipher;
-
ctx->auth = auth;
ctx->enc = enc;
- ctx->null = null;
ctx->reqoff = 2 * crypto_ahash_digestsize(auth);
@@ -358,8 +329,6 @@ static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
return 0;
-err_free_skcipher:
- crypto_free_skcipher(enc);
err_free_ahash:
crypto_free_ahash(auth);
return err;
@@ -371,7 +340,6 @@ static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
crypto_free_ahash(ctx->auth);
crypto_free_skcipher(ctx->enc);
- crypto_put_default_null_skcipher();
}
static void crypto_authenc_esn_free(struct aead_instance *inst)
--
2.53.0
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