From: Milan Broz <gmazyland@gmail.com>
To: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Milan Broz <gmazyland@gmail.com>
Subject: [PATCH] algif_skcipher: Avoid crash if buffer is not multiple of cipher block size
Date: Sun, 14 Apr 2013 18:12:32 +0200 [thread overview]
Message-ID: <1365955952-12381-1-git-send-email-gmazyland@gmail.com> (raw)
When user requests encryption (or decryption) of block which
is not aligned to cipher block size through userspace crypto
interface, an OOps like this can happen:
[ 112.738285] BUG: unable to handle kernel paging request at e1c44840
[ 112.738407] IP: [<c121f473>] scatterwalk_done+0x53/0x70
...
[ 112.740515] Call Trace:
[ 112.740588] [<c1221d30>] blkcipher_walk_done+0x160/0x1e0
[ 112.740663] [<c12220c8>] blkcipher_walk_next+0x318/0x3c0
[ 112.740737] [<c12221e0>] blkcipher_walk_first+0x70/0x160
[ 112.740811] [<c1222327>] blkcipher_walk_virt+0x17/0x20
[ 112.740886] [<e0ce4249>] cbc_encrypt+0x29/0x100 [aesni_intel]
[ 112.740968] [<c1029f73>] ? get_user_pages_fast+0x123/0x150
[ 112.741046] [<c106e7db>] ? trace_hardirqs_on+0xb/0x10
[ 112.741119] [<e081e1c9>] __ablk_encrypt+0x39/0x40 [ablk_helper]
[ 112.741198] [<e081e1ea>] ablk_encrypt+0x1a/0x70 [ablk_helper]
[ 112.741275] [<e0f715ac>] skcipher_recvmsg+0x20c/0x400 [algif_skcipher]
[ 112.741359] [<c1056a1d>] ? sched_clock_cpu+0x11d/0x1a0
[ 112.741435] [<c10a5eb9>] ? find_get_page+0x79/0xc0
[ 112.741509] [<c135e034>] sock_aio_read+0x104/0x140
[ 112.741580] [<c10be638>] ? __do_fault+0x248/0x420
[ 112.741650] [<c10d3d27>] do_sync_read+0x97/0xd0
[ 112.741719] [<c10d45ed>] vfs_read+0x11d/0x140
[ 112.741789] [<c135f683>] ? sys_socketcall+0x2a3/0x320
[ 112.741861] [<c10d4762>] sys_read+0x42/0x90
[ 112.742578] [<c141c27a>] sysenter_do_call+0x12/0x32
Patch fixes it by simply rejecting buffer which is not multiple of cipher block.
(Bug is present in all stable kernels as well.)
Signed-off-by: Milan Broz <gmazyland@gmail.com>
---
crypto/algif_skcipher.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 6a6dfc0..5f7713b 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -463,7 +463,7 @@ static int skcipher_recvmsg(struct kiocb *unused, struct socket *sock,
used -= used % bs;
err = -EINVAL;
- if (!used)
+ if (!used || used % bs)
goto free;
ablkcipher_request_set_crypt(&ctx->req, sg,
--
1.7.10.4
next reply other threads:[~2013-04-14 16:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-14 16:12 Milan Broz [this message]
2013-04-14 16:17 ` Milan Broz
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