From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759550AbcCDQNp (ORCPT ); Fri, 4 Mar 2016 11:13:45 -0500 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:60599 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756996AbcCDQCp (ORCPT ); Fri, 4 Mar 2016 11:02:45 -0500 Message-Id: <20160304153001.841028670@1wt.eu> User-Agent: quilt/0.63-1 Date: Fri, 04 Mar 2016 16:30:26 +0100 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vegard Nossum , Jan Kara , Quentin Casasnovas , Andrew Morton , Jan Kara , Ben Hutchings , Willy Tarreau Subject: [PATCH 2.6.32 26/55] udf: limit the maximum number of indirect extents in a row MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 In-Reply-To: <148ee355b419e9976ca727513a1405c8@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Vegard Nossum commit b0918d9f476a8434b055e362b83fa4fd1d462c3f upstream. udf_next_aext() just follows extent pointers while extents are marked as indirect. This can loop forever for corrupted filesystem. Limit number the of indirect extents we are willing to follow in a row. [JK: Updated changelog, limit, style] Signed-off-by: Vegard Nossum Cc: Jan Kara Cc: Quentin Casasnovas Cc: Andrew Morton Signed-off-by: Jan Kara Signed-off-by: Ben Hutchings [wt: udf_error() instead of udf_err() in 2.6.32] Signed-off-by: Willy Tarreau --- fs/udf/inode.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/fs/udf/inode.c b/fs/udf/inode.c index b8d7a0e..a22f568 100644 --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -1869,14 +1869,29 @@ int8_t udf_write_aext(struct inode *inode, struct extent_position *epos, return (elen >> 30); } +/* + * Only 1 indirect extent in a row really makes sense but allow upto 16 in case + * someone does some weird stuff. + */ +#define UDF_MAX_INDIR_EXTS 16 + int8_t udf_next_aext(struct inode *inode, struct extent_position *epos, struct kernel_lb_addr *eloc, uint32_t *elen, int inc) { int8_t etype; + unsigned int indirections = 0; while ((etype = udf_current_aext(inode, epos, eloc, elen, inc)) == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) { int block; + + if (++indirections > UDF_MAX_INDIR_EXTS) { + udf_error(inode->i_sb, __func__, + "too many indirect extents in inode %lu\n", + inode->i_ino); + return -1; + } + epos->block = *eloc; epos->offset = sizeof(struct allocExtDesc); brelse(epos->bh); -- 1.7.12.2.21.g234cd45.dirty