Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752397AbbBQBxR (ORCPT ); Mon, 16 Feb 2015 20:53:17 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33738 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752276AbbBQBvP (ORCPT ); Mon, 16 Feb 2015 20:51:15 -0500 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, "P J P" , "Jan Kara" Date: Tue, 17 Feb 2015 01:46:53 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 060/152] isofs: Fix infinite looping over CE entries In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 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: 1776 Lines: 59 3.2.67-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit f54e18f1b831c92f6512d2eedb224cd63d607d3d upstream. Rock Ridge extensions define so called Continuation Entries (CE) which define where is further space with Rock Ridge data. Corrupted isofs image can contain arbitrarily long chain of these, including a one containing loop and thus causing kernel to end in an infinite loop when traversing these entries. Limit the traversal to 32 entries which should be more than enough space to store all the Rock Ridge data. Reported-by: P J P Signed-off-by: Jan Kara Signed-off-by: Ben Hutchings --- fs/isofs/rock.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/isofs/rock.c +++ b/fs/isofs/rock.c @@ -30,6 +30,7 @@ struct rock_state { int cont_size; int cont_extent; int cont_offset; + int cont_loops; struct inode *inode; }; @@ -73,6 +74,9 @@ static void init_rock_state(struct rock_ rs->inode = inode; } +/* Maximum number of Rock Ridge continuation entries */ +#define RR_MAX_CE_ENTRIES 32 + /* * Returns 0 if the caller should continue scanning, 1 if the scan must end * and -ve on error. @@ -105,6 +109,8 @@ static int rock_continue(struct rock_sta goto out; } ret = -EIO; + if (++rs->cont_loops >= RR_MAX_CE_ENTRIES) + goto out; bh = sb_bread(rs->inode->i_sb, rs->cont_extent); if (bh) { memcpy(rs->buffer, bh->b_data + rs->cont_offset, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/