Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932436AbcDJUht (ORCPT ); Sun, 10 Apr 2016 16:37:49 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:58114 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932201AbcDJUgA (ORCPT ); Sun, 10 Apr 2016 16:36:00 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "J. Bruce Fields" Subject: [PATCH 4.5 215/238] nfsd4: fix bad bounds checking Date: Sun, 10 Apr 2016 11:36:32 -0700 Message-Id: <20160410183507.880785011@linuxfoundation.org> X-Mailer: git-send-email 2.8.0 In-Reply-To: <20160410183456.398741366@linuxfoundation.org> References: <20160410183456.398741366@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2322 Lines: 70 4.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: J. Bruce Fields commit 4aed9c46afb80164401143aa0fdcfe3798baa9d5 upstream. A number of spots in the xdr decoding follow a pattern like n = be32_to_cpup(p++); READ_BUF(n + 4); where n is a u32. The only bounds checking is done in READ_BUF itself, but since it's checking (n + 4), it won't catch cases where n is very large, (u32)(-4) or higher. I'm not sure exactly what the consequences are, but we've seen crashes soon after. Instead, just break these up into two READ_BUF()s. Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/nfs4xdr.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -1072,8 +1072,9 @@ nfsd4_decode_rename(struct nfsd4_compoun READ_BUF(4); rename->rn_snamelen = be32_to_cpup(p++); - READ_BUF(rename->rn_snamelen + 4); + READ_BUF(rename->rn_snamelen); SAVEMEM(rename->rn_sname, rename->rn_snamelen); + READ_BUF(4); rename->rn_tnamelen = be32_to_cpup(p++); READ_BUF(rename->rn_tnamelen); SAVEMEM(rename->rn_tname, rename->rn_tnamelen); @@ -1155,13 +1156,14 @@ nfsd4_decode_setclientid(struct nfsd4_co READ_BUF(8); setclientid->se_callback_prog = be32_to_cpup(p++); setclientid->se_callback_netid_len = be32_to_cpup(p++); - - READ_BUF(setclientid->se_callback_netid_len + 4); + READ_BUF(setclientid->se_callback_netid_len); SAVEMEM(setclientid->se_callback_netid_val, setclientid->se_callback_netid_len); + READ_BUF(4); setclientid->se_callback_addr_len = be32_to_cpup(p++); - READ_BUF(setclientid->se_callback_addr_len + 4); + READ_BUF(setclientid->se_callback_addr_len); SAVEMEM(setclientid->se_callback_addr_val, setclientid->se_callback_addr_len); + READ_BUF(4); setclientid->se_callback_ident = be32_to_cpup(p++); DECODE_TAIL; @@ -1835,8 +1837,9 @@ nfsd4_decode_compound(struct nfsd4_compo READ_BUF(4); argp->taglen = be32_to_cpup(p++); - READ_BUF(argp->taglen + 8); + READ_BUF(argp->taglen); SAVEMEM(argp->tag, argp->taglen); + READ_BUF(8); argp->minorversion = be32_to_cpup(p++); argp->opcnt = be32_to_cpup(p++); max_reply += 4 + (XDR_QUADLEN(argp->taglen) << 2);