Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932274Ab2ENVEI (ORCPT ); Mon, 14 May 2012 17:04:08 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:47164 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758008Ab2ENVED (ORCPT ); Mon, 14 May 2012 17:04:03 -0400 Date: Mon, 14 May 2012 14:03:53 -0700 From: Tejun Heo To: Dave Jones , Jens Axboe Cc: Linux Kernel , Szymon Gruszczynski , Fedora Kernel Team , Al Viro Subject: [PATCH] block: fix buffer overflow when printing partition UUIDs Message-ID: <20120514210353.GJ2366@google.com> References: <20120509195848.GA961@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120509195848.GA961@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3442 Lines: 91 6d1d8050b4bc8 "block, partition: add partition_meta_info to hd_struct" added part_unpack_uuid() which assumes that the passed in buffer has enough space for sprintfing "%pU" - 37 characters including '\0'. Unfortunately, b5af921ec0233 "init: add support for root devices specified by partition UUID" supplied 33 bytes buffer to the function leading to the following panic with stackprotector enabled. Kernel panic - not syncing: stack-protector: Kernel stack corrupted in: ffffffff81b14c7e [] panic+0xba/0x1c6 [] ? printk_all_partitions+0x259/0x26xb [] __stack_chk_fail+0x1b/0x20 [] printk_all_paritions+0x259/0x26xb [] mount_block_root+0x1bc/0x27f [] mount_root+0x57/0x5b [] prepare_namespace+0x13d/0x176 [] ? release_tgcred.isra.4+0x330/0x30 [] kernel_init+0x155/0x15a [] ? schedule_tail+0x27/0xb0 [] kernel_thread_helper+0x5/0x10 [] ? start_kernel+0x3c5/0x3c5 [] ? gs_change+0x13/0x13 Increase the buffer size, remove the dangerous part_unpack_uuid() and use snprintf() directly from printk_all_partitions(). Signed-off-by: Tejun Heo Reported-by: Szymon Gruszczynski Cc: Will Drewry Cc: stable@vger.kernel.org --- block/genhd.c | 10 ++++++---- include/linux/genhd.h | 6 ------ 2 files changed, 6 insertions(+), 10 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index df9816e..9cf5583 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -743,7 +743,7 @@ void __init printk_all_partitions(void) struct hd_struct *part; char name_buf[BDEVNAME_SIZE]; char devt_buf[BDEVT_SIZE]; - u8 uuid[PARTITION_META_INFO_UUIDLTH * 2 + 1]; + char uuid_buf[PARTITION_META_INFO_UUIDLTH * 2 + 5]; /* * Don't show empty devices or things that have been @@ -762,14 +762,16 @@ void __init printk_all_partitions(void) while ((part = disk_part_iter_next(&piter))) { bool is_part0 = part == &disk->part0; - uuid[0] = 0; + uuid_buf[0] = '\0'; if (part->info) - part_unpack_uuid(part->info->uuid, uuid); + snprintf(uuid_buf, sizeof(uuid_buf), "%pU", + part->info->uuid); printk("%s%s %10llu %s %s", is_part0 ? "" : " ", bdevt_str(part_devt(part), devt_buf), (unsigned long long)part->nr_sects >> 1, - disk_name(disk, part->partno, name_buf), uuid); + disk_name(disk, part->partno, name_buf), + uuid_buf); if (is_part0) { if (disk->driverfs_dev != NULL && disk->driverfs_dev->driver != NULL) diff --git a/include/linux/genhd.h b/include/linux/genhd.h index e61d319..017a7fb 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -222,12 +222,6 @@ static inline void part_pack_uuid(const u8 *uuid_str, u8 *to) } } -static inline char *part_unpack_uuid(const u8 *uuid, char *out) -{ - sprintf(out, "%pU", uuid); - return out; -} - static inline int disk_max_parts(struct gendisk *disk) { if (disk->flags & GENHD_FL_EXT_DEVT) -- 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/