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| author | Pavel Skripkin <paskripkin@gmail.com> | 2023-08-14 21:03:41 +0300 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2023-08-18 18:30:09 +0800 |
| commit | 080aa61e370b9c5cafe71cacadbfe0e72db4d6df (patch) | |
| tree | e36d58dc6d430b6fc968c771b357a545a2181d93 /crypto | |
| parent | 83874b8e97f895e62d9ab03223318176d5e78203 (diff) | |
| download | lwn-080aa61e370b9c5cafe71cacadbfe0e72db4d6df.tar.gz lwn-080aa61e370b9c5cafe71cacadbfe0e72db4d6df.zip | |
crypto: fix uninit-value in af_alg_free_resources
Syzbot was able to trigger use of uninitialized memory in
af_alg_free_resources.
Bug is caused by missing initialization of rsgl->sgl.need_unpin before
adding to rsgl_list. Then in case of extract_iter_to_sg() failure, rsgl
is left with uninitialized need_unpin which is read during clean up
BUG: KMSAN: uninit-value in af_alg_free_sg crypto/af_alg.c:545 [inline]
BUG: KMSAN: uninit-value in af_alg_free_areq_sgls crypto/af_alg.c:778 [inline]
BUG: KMSAN: uninit-value in af_alg_free_resources+0x3d1/0xf60 crypto/af_alg.c:1117
af_alg_free_sg crypto/af_alg.c:545 [inline]
af_alg_free_areq_sgls crypto/af_alg.c:778 [inline]
af_alg_free_resources+0x3d1/0xf60 crypto/af_alg.c:1117
_skcipher_recvmsg crypto/algif_skcipher.c:144 [inline]
...
Uninit was created at:
slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767
slab_alloc_node mm/slub.c:3470 [inline]
__kmem_cache_alloc_node+0x536/0x8d0 mm/slub.c:3509
__do_kmalloc_node mm/slab_common.c:984 [inline]
__kmalloc+0x121/0x3c0 mm/slab_common.c:998
kmalloc include/linux/slab.h:586 [inline]
sock_kmalloc+0x128/0x1c0 net/core/sock.c:2683
af_alg_alloc_areq+0x41/0x2a0 crypto/af_alg.c:1188
_skcipher_recvmsg crypto/algif_skcipher.c:71 [inline]
Fixes: c1abe6f570af ("crypto: af_alg: Use extract_iter_to_sg() to create scatterlists")
Reported-and-tested-by: syzbot+cba21d50095623218389@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=cba21d50095623218389
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/af_alg.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 06b15b9f661c..10efb56d8b48 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -1241,6 +1241,8 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags, return -ENOMEM; } + rsgl->sgl.need_unpin = + iov_iter_extract_will_pin(&msg->msg_iter); rsgl->sgl.sgt.sgl = rsgl->sgl.sgl; rsgl->sgl.sgt.nents = 0; rsgl->sgl.sgt.orig_nents = 0; @@ -1255,8 +1257,6 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags, } sg_mark_end(rsgl->sgl.sgt.sgl + rsgl->sgl.sgt.nents - 1); - rsgl->sgl.need_unpin = - iov_iter_extract_will_pin(&msg->msg_iter); /* chain the new scatterlist with previous one */ if (areq->last_rsgl) |