From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1MUQMz-0000xt-2n for mharc-grub-devel@gnu.org; Fri, 24 Jul 2009 15:23:53 -0400 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MUQMx-0000x6-3V for grub-devel@gnu.org; Fri, 24 Jul 2009 15:23:51 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MUQMs-0000uq-1G for grub-devel@gnu.org; Fri, 24 Jul 2009 15:23:50 -0400 Received: from [199.232.76.173] (port=41076 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MUQMr-0000ul-Ry for grub-devel@gnu.org; Fri, 24 Jul 2009 15:23:45 -0400 Received: from moutng.kundenserver.de ([212.227.126.188]:56910) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MUQMr-0001AE-7x for grub-devel@gnu.org; Fri, 24 Jul 2009 15:23:45 -0400 Received: from [85.180.4.132] (e180004132.adsl.alicedsl.de [85.180.4.132]) by mrelayeu.kundenserver.de (node=mreu0) with ESMTP (Nemesis) id 0MKuxg-1MUQMp2hXb-0008QW; Fri, 24 Jul 2009 21:23:43 +0200 From: Felix Zielcke To: The development of GRUB 2 In-Reply-To: <1248454704.3510.67.camel@fz.local> References: <1248454704.3510.67.camel@fz.local> Content-Type: multipart/mixed; boundary="=-hniyN8MF32SkgtmS6zNE" Date: Fri, 24 Jul 2009 21:24:31 +0200 Message-Id: <1248463471.3510.77.camel@fz.local> Mime-Version: 1.0 X-Mailer: Evolution 2.27.4 X-Provags-ID: V01U2FsdGVkX1/hIUlE/+vWeFlmyu6+dp9lSQbOLLIfupP2XuC BOWbceDQkrnKrC6ZXfBH/kY89MYVGaXPPmsGvWNbQML35csllE fUMjkKuGkcSWD1kFzSwkw== X-detected-operating-system: by monty-python.gnu.org: Genre and OS details not recognized. Subject: Re: [PATCH] fix an infinite loop with a corrupted pc partition table X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: The development of GRUB 2 List-Id: The development of GRUB 2 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Jul 2009 19:23:51 -0000 --=-hniyN8MF32SkgtmS6zNE Content-Type: text/plain Content-Transfer-Encoding: 7bit Am Freitag, den 24.07.2009, 18:58 +0200 schrieb Felix Zielcke: > > > With this [0] partition table grub-probe currently loops forever: > > kern/disk.c:389: Reading `hd1'... > partmap/pc.c:142: partition 0: flag 0x0, type 0x5, start 0x0, len > 0x11177330 > partmap/pc.c:142: partition 1: flag 0x0, type 0x0, start 0x0, len 0x0 > partmap/pc.c:142: partition 2: flag 0x0, type 0x0, start 0x0, len 0x0 > partmap/pc.c:142: partition 3: flag 0x0, type 0x0, start 0x0, len 0x0 > kern/disk.c:389: Reading `hd1'... > partmap/pc.c:142: partition 0: flag 0x0, type 0x5, start 0x0, len > 0x11177330 > partmap/pc.c:142: partition 1: flag 0x0, type 0x0, start 0x0, len 0x0 > partmap/pc.c:142: partition 2: flag 0x0, type 0x0, start 0x0, len 0x0 > partmap/pc.c:142: partition 3: flag 0x0, type 0x0, start 0x0, len 0x0 > [...] > > This patch fixes it, but probable there's a better fix. > > > [0] > http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5;filename=corrupt-table.dat;att=1;bug=519223 Here's a new one after comments from Vladimir on IRC loop count is increased to 100'000 and partitions with a starting sector of 0 are ignored. -- Felix Zielcke --=-hniyN8MF32SkgtmS6zNE Content-Disposition: attachment; filename="corrupted_partmap.diff.2" Content-Type: text/plain; name="corrupted_partmap.diff.2"; charset="UTF-8" Content-Transfer-Encoding: 7bit 2009-07-24 Felix Zielcke * partmap/pc.c (pc_partition_map_iterate): Don't loop forever in case the partition table is corrupted. Also ignore partitions with a starting sector of 0. diff --git a/partmap/pc.c b/partmap/pc.c index 6f68ecf..ab58b3d 100644 --- a/partmap/pc.c +++ b/partmap/pc.c @@ -97,6 +97,7 @@ pc_partition_map_iterate (grub_disk_t disk, struct grub_pc_partition_mbr mbr; struct grub_pc_partition_disk_label label; struct grub_disk raw; + int loop; /* Enforce raw disk access. */ raw = *disk; @@ -108,11 +109,13 @@ pc_partition_map_iterate (grub_disk_t disk, p.data = &pcdata; p.partmap = &grub_pc_partition_map; - while (1) + loop = 0; + while (loop < 100000) { int i; struct grub_pc_partition_entry *e; + loop++; /* Read the MBR. */ if (grub_disk_read (&raw, p.offset, 0, sizeof (mbr), &mbr)) goto finish; @@ -143,7 +146,7 @@ pc_partition_map_iterate (grub_disk_t disk, return grub_error (GRUB_ERR_BAD_PART_TABLE, "dummy mbr"); /* If this partition is a normal one, call the hook. */ - if (! grub_pc_partition_is_empty (e->type) + if (e->start != 0 && ! grub_pc_partition_is_empty (e->type) && ! grub_pc_partition_is_extended (e->type)) { pcdata.dos_part++; @@ -206,7 +209,7 @@ pc_partition_map_iterate (grub_disk_t disk, { e = mbr.entries + i; - if (grub_pc_partition_is_extended (e->type)) + if (e->start != 0 && grub_pc_partition_is_extended (e->type)) { p.offset = pcdata.ext_offset + grub_le_to_cpu32 (e->start); if (! pcdata.ext_offset) @@ -221,6 +224,8 @@ pc_partition_map_iterate (grub_disk_t disk, break; } + if (loop == 100000) + return grub_error (GRUB_ERR_BAD_PART_TABLE, "Corrupted partition table found."); finish: return grub_errno; } --=-hniyN8MF32SkgtmS6zNE--