[SRU][J][PATCH 2/9] crypto: algif_aead - use memcpy_sglist() instead of null skcipher
Massimiliano Pellizzer
massimiliano.pellizzer at canonical.com
Thu Apr 30 12:30:30 UTC 2026
From: Eric Biggers <ebiggers at google.com>
commit f2804d0eee8ddd57aa79d0b82872b74c21e1b69b 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 17774d99bb4347c6b025ef80b637d6e3f94fe2f7 linux-5.15.y)
CVE-2026-31431
Signed-off-by: Massimiliano Pellizzer <massimiliano.pellizzer at canonical.com>
---
crypto/Kconfig | 1 -
crypto/algif_aead.c | 98 ++++++++-------------------------------------
2 files changed, 17 insertions(+), 82 deletions(-)
diff --git a/crypto/Kconfig b/crypto/Kconfig
index db260ccfba51b..15994570627bf 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1872,7 +1872,6 @@ config CRYPTO_USER_API_AEAD
depends on NET
select CRYPTO_AEAD
select CRYPTO_SKCIPHER
- select CRYPTO_NULL
select CRYPTO_USER_API
help
This option enables the user-spaces interface for AEAD
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 42493b4d8ce46..38a4ab8c90c72 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -27,7 +27,6 @@
#include <crypto/scatterwalk.h>
#include <crypto/if_alg.h>
#include <crypto/skcipher.h>
-#include <crypto/null.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/kernel.h>
@@ -36,19 +35,13 @@
#include <linux/net.h>
#include <net/sock.h>
-struct aead_tfm {
- struct crypto_aead *aead;
- struct crypto_sync_skcipher *null_tfm;
-};
-
static inline bool aead_sufficient_data(struct sock *sk)
{
struct alg_sock *ask = alg_sk(sk);
struct sock *psk = ask->parent;
struct alg_sock *pask = alg_sk(psk);
struct af_alg_ctx *ctx = ask->private;
- struct aead_tfm *aeadc = pask->private;
- struct crypto_aead *tfm = aeadc->aead;
+ struct crypto_aead *tfm = pask->private;
unsigned int as = crypto_aead_authsize(tfm);
/*
@@ -64,27 +57,12 @@ static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
struct alg_sock *ask = alg_sk(sk);
struct sock *psk = ask->parent;
struct alg_sock *pask = alg_sk(psk);
- struct aead_tfm *aeadc = pask->private;
- struct crypto_aead *tfm = aeadc->aead;
+ struct crypto_aead *tfm = pask->private;
unsigned int ivsize = crypto_aead_ivsize(tfm);
return af_alg_sendmsg(sock, msg, size, ivsize);
}
-static int crypto_aead_copy_sgl(struct crypto_sync_skcipher *null_tfm,
- struct scatterlist *src,
- struct scatterlist *dst, unsigned int len)
-{
- SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, null_tfm);
-
- skcipher_request_set_sync_tfm(skreq, null_tfm);
- skcipher_request_set_callback(skreq, CRYPTO_TFM_REQ_MAY_SLEEP,
- NULL, NULL);
- skcipher_request_set_crypt(skreq, src, dst, len, NULL);
-
- return crypto_skcipher_encrypt(skreq);
-}
-
static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
size_t ignored, int flags)
{
@@ -93,9 +71,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
struct sock *psk = ask->parent;
struct alg_sock *pask = alg_sk(psk);
struct af_alg_ctx *ctx = ask->private;
- struct aead_tfm *aeadc = pask->private;
- struct crypto_aead *tfm = aeadc->aead;
- struct crypto_sync_skcipher *null_tfm = aeadc->null_tfm;
+ struct crypto_aead *tfm = pask->private;
unsigned int i, as = crypto_aead_authsize(tfm);
struct af_alg_async_req *areq;
struct af_alg_tsgl *tsgl, *tmp;
@@ -223,10 +199,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
* v v
* RX SGL: AAD || PT || Tag
*/
- err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
- areq->first_rsgl.sgl.sg, processed);
- if (err)
- goto free;
+ memcpy_sglist(areq->first_rsgl.sgl.sg, tsgl_src, processed);
af_alg_pull_tsgl(sk, processed, NULL, 0);
} else {
/*
@@ -240,11 +213,8 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
* RX SGL: AAD || CT ----+
*/
- /* Copy AAD || CT to RX SGL buffer for in-place operation. */
- err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
- areq->first_rsgl.sgl.sg, outlen);
- if (err)
- goto free;
+ /* Copy AAD || CT to RX SGL buffer for in-place operation. */
+ memcpy_sglist(areq->first_rsgl.sgl.sg, tsgl_src, outlen);
/* Create TX SGL for tag and chain it to RX SGL. */
areq->tsgl_entries = af_alg_count_tsgl(sk, processed,
@@ -378,7 +348,7 @@ static int aead_check_key(struct socket *sock)
int err = 0;
struct sock *psk;
struct alg_sock *pask;
- struct aead_tfm *tfm;
+ struct crypto_aead *tfm;
struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk);
@@ -392,7 +362,7 @@ static int aead_check_key(struct socket *sock)
err = -ENOKEY;
lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
- if (crypto_aead_get_flags(tfm->aead) & CRYPTO_TFM_NEED_KEY)
+ if (crypto_aead_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
goto unlock;
atomic_dec(&pask->nokey_refcnt);
@@ -466,54 +436,22 @@ static struct proto_ops algif_aead_ops_nokey = {
static void *aead_bind(const char *name, u32 type, u32 mask)
{
- struct aead_tfm *tfm;
- struct crypto_aead *aead;
- struct crypto_sync_skcipher *null_tfm;
-
- tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
- if (!tfm)
- return ERR_PTR(-ENOMEM);
-
- aead = crypto_alloc_aead(name, type, mask);
- if (IS_ERR(aead)) {
- kfree(tfm);
- return ERR_CAST(aead);
- }
-
- null_tfm = crypto_get_default_null_skcipher();
- if (IS_ERR(null_tfm)) {
- crypto_free_aead(aead);
- kfree(tfm);
- return ERR_CAST(null_tfm);
- }
-
- tfm->aead = aead;
- tfm->null_tfm = null_tfm;
-
- return tfm;
+ return crypto_alloc_aead(name, type, mask);
}
static void aead_release(void *private)
{
- struct aead_tfm *tfm = private;
-
- crypto_free_aead(tfm->aead);
- crypto_put_default_null_skcipher();
- kfree(tfm);
+ crypto_free_aead(private);
}
static int aead_setauthsize(void *private, unsigned int authsize)
{
- struct aead_tfm *tfm = private;
-
- return crypto_aead_setauthsize(tfm->aead, authsize);
+ return crypto_aead_setauthsize(private, authsize);
}
static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
{
- struct aead_tfm *tfm = private;
-
- return crypto_aead_setkey(tfm->aead, key, keylen);
+ return crypto_aead_setkey(private, key, keylen);
}
static void aead_sock_destruct(struct sock *sk)
@@ -522,8 +460,7 @@ static void aead_sock_destruct(struct sock *sk)
struct af_alg_ctx *ctx = ask->private;
struct sock *psk = ask->parent;
struct alg_sock *pask = alg_sk(psk);
- struct aead_tfm *aeadc = pask->private;
- struct crypto_aead *tfm = aeadc->aead;
+ struct crypto_aead *tfm = pask->private;
unsigned int ivlen = crypto_aead_ivsize(tfm);
af_alg_pull_tsgl(sk, ctx->used, NULL, 0);
@@ -536,10 +473,9 @@ static int aead_accept_parent_nokey(void *private, struct sock *sk)
{
struct af_alg_ctx *ctx;
struct alg_sock *ask = alg_sk(sk);
- struct aead_tfm *tfm = private;
- struct crypto_aead *aead = tfm->aead;
+ struct crypto_aead *tfm = private;
unsigned int len = sizeof(*ctx);
- unsigned int ivlen = crypto_aead_ivsize(aead);
+ unsigned int ivlen = crypto_aead_ivsize(tfm);
ctx = sock_kmalloc(sk, len, GFP_KERNEL);
if (!ctx)
@@ -566,9 +502,9 @@ static int aead_accept_parent_nokey(void *private, struct sock *sk)
static int aead_accept_parent(void *private, struct sock *sk)
{
- struct aead_tfm *tfm = private;
+ struct crypto_aead *tfm = private;
- if (crypto_aead_get_flags(tfm->aead) & CRYPTO_TFM_NEED_KEY)
+ if (crypto_aead_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
return -ENOKEY;
return aead_accept_parent_nokey(private, sk);
--
2.53.0
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