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| author | David Howells <dhowells@redhat.com> | 2023-06-15 23:08:54 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-06-18 15:26:21 +0200 |
| commit | 4380499218c6a1aa77e80e3bf6da107dd8babf62 (patch) | |
| tree | d0f155b2c2f6cd18064fd63f8b7ce17ca7b859c7 /crypto/af_alg.c | |
| parent | tcp: Use per-vma locking for receive zerocopy (diff) | |
| download | linux-4380499218c6a1aa77e80e3bf6da107dd8babf62.tar.xz linux-4380499218c6a1aa77e80e3bf6da107dd8babf62.zip | |
crypto: Fix af_alg_sendmsg(MSG_SPLICE_PAGES) sglist limit
When af_alg_sendmsg() calls extract_iter_to_sg(), it passes MAX_SGL_ENTS as
the maximum number of elements that may be written to, but some of the
elements may already have been used (as recorded in sgl->cur), so
extract_iter_to_sg() may end up overrunning the scatterlist.
Fix this to limit the number of elements to "MAX_SGL_ENTS - sgl->cur".
Note: It probably makes sense in future to alter the behaviour of
extract_iter_to_sg() to stop if "sgtable->nents >= sg_max" instead, but
this is a smaller fix for now.
The bug causes errors looking something like:
BUG: KASAN: slab-out-of-bounds in sg_assign_page include/linux/scatterlist.h:109 [inline]
BUG: KASAN: slab-out-of-bounds in sg_set_page include/linux/scatterlist.h:139 [inline]
BUG: KASAN: slab-out-of-bounds in extract_bvec_to_sg lib/scatterlist.c:1183 [inline]
BUG: KASAN: slab-out-of-bounds in extract_iter_to_sg lib/scatterlist.c:1352 [inline]
BUG: KASAN: slab-out-of-bounds in extract_iter_to_sg+0x17a6/0x1960 lib/scatterlist.c:1339
Fixes: bf63e250c4b1 ("crypto: af_alg: Support MSG_SPLICE_PAGES")
Reported-by: syzbot+6efc50cc1f8d718d6cb7@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/000000000000b2585a05fdeb8379@google.com/
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: syzbot+6efc50cc1f8d718d6cb7@syzkaller.appspotmail.com
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-crypto@vger.kernel.org
cc: netdev@vger.kernel.org
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'crypto/af_alg.c')
| -rw-r--r-- | crypto/af_alg.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 7d4b6016b83d..cdb1dcc5dd1a 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -1043,7 +1043,7 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size, }; plen = extract_iter_to_sg(&msg->msg_iter, len, &sgtable, - MAX_SGL_ENTS, 0); + MAX_SGL_ENTS - sgl->cur, 0); if (plen < 0) { err = plen; goto unlock; |