From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755501AbcA2CNF (ORCPT ); Thu, 28 Jan 2016 21:13:05 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:60922 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752610AbcA2BUo (ORCPT ); Thu, 28 Jan 2016 20:20:44 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Vegard Nossum , Jan Kara , Quentin Casasnovas , Andrew Morton , Jan Kara , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 036/210] udf: limit the maximum number of indirect extents in a row Date: Thu, 28 Jan 2016 17:16:14 -0800 Message-Id: <1454030348-17736-37-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1454030348-17736-1-git-send-email-kamal@canonical.com> References: <1454030348-17736-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt14 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ 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: Kamal Mostafa --- fs/udf/inode.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/fs/udf/inode.c b/fs/udf/inode.c index 7b72b7d..9ae690d 100644 --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -2054,14 +2054,29 @@ void udf_write_aext(struct inode *inode, struct extent_position *epos, epos->offset += adsize; } +/* + * 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_err(inode->i_sb, + "too many indirect extents in inode %lu\n", + inode->i_ino); + return -1; + } + epos->block = *eloc; epos->offset = sizeof(struct allocExtDesc); brelse(epos->bh); -- 1.9.1