Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752348AbdFAPrl (ORCPT ); Thu, 1 Jun 2017 11:47:41 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33836 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752258AbdFAPpY (ORCPT ); Thu, 1 Jun 2017 11:45:24 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Steffen Klassert" , "Andy Whitcroft" , "Linus Torvalds" Date: Thu, 01 Jun 2017 16:43:16 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 186/212] xfrm_user: validate XFRM_MSG_NEWAE XFRMA_REPLAY_ESN_VAL replay_window In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1812 Lines: 47 3.16.44-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Andy Whitcroft commit 677e806da4d916052585301785d847c3b3e6186a upstream. When a new xfrm state is created during an XFRM_MSG_NEWSA call we validate the user supplied replay_esn to ensure that the size is valid and to ensure that the replay_window size is within the allocated buffer. However later it is possible to update this replay_esn via a XFRM_MSG_NEWAE call. There we again validate the size of the supplied buffer matches the existing state and if so inject the contents. We do not at this point check that the replay_window is within the allocated memory. This leads to out-of-bounds reads and writes triggered by netlink packets. This leads to memory corruption and the potential for priviledge escalation. We already attempt to validate the incoming replay information in xfrm_new_ae() via xfrm_replay_verify_len(). This confirms that the user is not trying to change the size of the replay state buffer which includes the replay_esn. It however does not check the replay_window remains within that buffer. Add validation of the contained replay_window. CVE-2017-7184 Signed-off-by: Andy Whitcroft Acked-by: Steffen Klassert Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- net/xfrm/xfrm_user.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -390,6 +390,9 @@ static inline int xfrm_replay_verify_len if (nla_len(rp) < ulen || xfrm_replay_state_esn_len(replay_esn) != ulen) return -EINVAL; + if (up->replay_window > up->bmp_len * sizeof(__u32) * 8) + return -EINVAL; + return 0; }