From: Milan Broz Subject: [PATCH] algif_skcipher: Avoid crash if buffer is not multiple of cipher block size Date: Mon, 29 Oct 2012 14:04:21 +0100 Message-ID: <1351515861-3596-1-git-send-email-mbroz@redhat.com> Cc: Milan Broz To: linux-crypto@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:58967 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756512Ab2J2NEY (ORCPT ); Mon, 29 Oct 2012 09:04:24 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q9TD4OWk015828 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 29 Oct 2012 09:04:24 -0400 Sender: linux-crypto-owner@vger.kernel.org List-ID: When user requests encryption (or decryption) of block which is not aligned to cipher block size, an OOps like this can happen: [ 37.672185] BUG: unable to handle kernel paging request at e1c5fbc0 [ 37.672457] IP: [] scatterwalk_done+0x53/0x70 ... [ 37.679183] Call Trace: [ 37.679326] [] blkcipher_walk_done+0x160/0x1e0 [ 37.679516] [] blkcipher_walk_next+0x318/0x3c0 [ 37.679707] [] ? native_sched_clock+0x2c/0xb0 [ 37.679895] [] blkcipher_walk_first+0x70/0x160 [ 37.680082] [] blkcipher_walk_virt+0x17/0x20 [ 37.680272] [] cbc_encrypt+0x29/0x100 [aesni_intel] [ 37.680472] [] ? get_user_pages_fast+0x123/0x150 [ 37.680665] [] ? trace_hardirqs_on+0xb/0x10 [ 37.680851] [] __ablk_encrypt+0x39/0x40 [ablk_helper] [ 37.681052] [] ablk_encrypt+0x1a/0x70 [ablk_helper] [ 37.681250] [] skcipher_recvmsg+0x20c/0x400 [algif_skcipher] [ 37.681474] [] ? sock_kfree_s+0x17/0x30 [ 37.681652] [] sock_aio_read+0x104/0x140 [ 37.681834] [] do_sync_read+0x97/0xd0 [ 37.682009] [] vfs_read+0x11d/0x140 [ 37.682183] [] ? sys_socketcall+0x2a3/0x320 [ 37.682366] [] sys_read+0x42/0x90 [ 37.682597] [] sysenter_do_call+0x12/0x32 Patch fixes it by simply rejecting buffer which is not multiple of cipher block. Signed-off-by: Milan Broz --- 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