From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932713AbcHNSFT (ORCPT ); Sun, 14 Aug 2016 14:05:19 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:54971 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753140AbcHNSAg (ORCPT ); Sun, 14 Aug 2016 14:00:36 -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, "=?UTF-8?q?Tom=C3=A1=C5=A1=20Trnka?=" , "J. Bruce Fields" , "Jeff Layton" Date: Sat, 13 Aug 2016 18:42:51 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 114/305] sunrpc: fix stripping of padded MIC tokens In-Reply-To: X-SA-Exim-Connect-IP: 92.40.249.202 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 3.16.37-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Tomáš Trnka commit c0cb8bf3a8e4bd82e640862cdd8891400405cb89 upstream. The length of the GSS MIC token need not be a multiple of four bytes. It is then padded by XDR to a multiple of 4 B, but unwrap_integ_data() would previously only trim mic.len + 4 B. The remaining up to three bytes would then trigger a check in nfs4svc_decode_compoundargs(), leading to a "garbage args" error and mount failure: nfs4svc_decode_compoundargs: compound not properly padded! nfsd: failed to decode arguments! This would prevent older clients using the pre-RFC 4121 MIC format (37-byte MIC including a 9-byte OID) from mounting exports from v3.9+ servers using krb5i. The trimming was introduced by commit 4c190e2f913f ("sunrpc: trim off trailing checksum before returning decrypted or integrity authenticated buffer"). Fixes: 4c190e2f913f "unrpc: trim off trailing checksum..." Signed-off-by: Tomáš Trnka Acked-by: Jeff Layton Signed-off-by: J. Bruce Fields Signed-off-by: Ben Hutchings --- net/sunrpc/auth_gss/svcauth_gss.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -855,8 +855,8 @@ unwrap_integ_data(struct svc_rqst *rqstp goto out; if (svc_getnl(&buf->head[0]) != seq) goto out; - /* trim off the mic at the end before returning */ - xdr_buf_trim(buf, mic.len + 4); + /* trim off the mic and padding at the end before returning */ + xdr_buf_trim(buf, round_up_to_quad(mic.len) + 4); stat = 0; out: kfree(mic.data);