diff options
| author | David Howells <dhowells@redhat.com> | 2023-07-07 10:12:38 +0100 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2023-07-08 22:48:42 +1000 |
| commit | 0b7ec177b589842c0abf9e91459c83ba28d32452 (patch) | |
| tree | 31082b1925f8697113c73038e890650f12986a59 /crypto/algif_hash.c | |
| parent | 9e9311e04e63ede92be98425efd843f9836336bd (diff) | |
crypto: algif_hash - Fix race between MORE and non-MORE sends
The 'MSG_MORE' state of the previous sendmsg() is fetched without the
socket lock held, so two sendmsg calls can race. This can be seen with a
large sendfile() as that now does a series of sendmsg() calls, and if a
write() comes in on the same socket at an inopportune time, it can flip the
state.
Fix this by moving the fetch of ctx->more inside the socket lock.
Fixes: c662b043cdca ("crypto: af_alg/hash: Support MSG_SPLICE_PAGES")
Reported-by: syzbot+689ec3afb1ef07b766b2@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/000000000000554b8205ffdea64e@google.com/
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: syzbot+689ec3afb1ef07b766b2@syzkaller.appspotmail.com
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: Paolo Abeni <pabeni@redhat.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: linux-crypto@vger.kernel.org
cc: netdev@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/algif_hash.c')
| -rw-r--r-- | crypto/algif_hash.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c index 0ab43e149f0e..82c44d4899b9 100644 --- a/crypto/algif_hash.c +++ b/crypto/algif_hash.c @@ -68,13 +68,15 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg, struct hash_ctx *ctx = ask->private; ssize_t copied = 0; size_t len, max_pages, npages; - bool continuing = ctx->more, need_init = false; + bool continuing, need_init = false; int err; max_pages = min_t(size_t, ALG_MAX_PAGES, DIV_ROUND_UP(sk->sk_sndbuf, PAGE_SIZE)); lock_sock(sk); + continuing = ctx->more; + if (!continuing) { /* Discard a previous request that wasn't marked MSG_MORE. */ hash_free_result(sk, ctx); |