* stack overflow in printk_all_partitions. @ 2012-05-09 19:58 Dave Jones 2012-05-14 21:03 ` [PATCH] block: fix buffer overflow when printing partition UUIDs Tejun Heo 0 siblings, 1 reply; 3+ messages in thread From: Dave Jones @ 2012-05-09 19:58 UTC (permalink / raw) To: Linux Kernel; +Cc: Szymon Gruszczynski, Fedora Kernel Team, Al Viro, Tejun Heo Szymon (cc'd) reported this oops that prevents his machine booting a 3.3.4 kernel. [ 2.892504] Kernel panic - not syncing: stack-protector: Kernel stack corrupted in: ffffffff81b14c7e [ 2.892506] [ 2.892872] [<ffffffff815e226b>] panic+0xba/0x1c6 [ 2.892961] [<ffffffff81b14c7e>] ? printk_all_partitions+0x259/0x26xb [ 2.893057] [<ffffffff810566bb>] __stack_chk_fail+0x1b/0x20 [ 2.893147] [<ffffffff81b15c7e>] printk_all_paritions+0x259/0x26xb [ 2.893244] [<ffffffff81aedfe0>] mount_block_root+0x1bc/0x27f [ 2.893336] [<ffffffff81aee0fa>] mount_root+0x57/0x5b [ 2.893425] [<ffffffff81aee23b>] prepare_namespace+0x13d/0x176 [ 2.893522] [<ffffffff8107eec0>] ? release_tgcred.isra.4+0x330/0x30 [ 2.893616] [<ffffffff81aedd60>] kernel_init+0x155/0x15a [ 2.893708] [<ffffffff81087b97>] ? schedule_tail+0x27/0xb0 [ 2.893800] [<ffffffff815f4d24>] kernel_thread_helper+0x5/0x10 [ 2.893893] [<ffffffff81aedc0b>] ? start_kernel+0x3c5/0x3c5 [ 2.893984] [<ffffffff815f4d20>] ? gs_change+0x13/0x13 His partition tables don't look anything out of the ordinary to me. http://wklej.org/id/748085/ Any ideas what's going wrong here ? original report at https://bugzilla.redhat.com/show_bug.cgi?id=819624, though all pertinent info so far is captured above. Dave ^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] block: fix buffer overflow when printing partition UUIDs 2012-05-09 19:58 stack overflow in printk_all_partitions Dave Jones @ 2012-05-14 21:03 ` Tejun Heo 2012-05-15 6:22 ` Jens Axboe 0 siblings, 1 reply; 3+ messages in thread From: Tejun Heo @ 2012-05-14 21:03 UTC (permalink / raw) To: Dave Jones, Jens Axboe Cc: Linux Kernel, Szymon Gruszczynski, Fedora Kernel Team, Al Viro 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 [<ffffffff815e226b>] panic+0xba/0x1c6 [<ffffffff81b14c7e>] ? printk_all_partitions+0x259/0x26xb [<ffffffff810566bb>] __stack_chk_fail+0x1b/0x20 [<ffffffff81b15c7e>] printk_all_paritions+0x259/0x26xb [<ffffffff81aedfe0>] mount_block_root+0x1bc/0x27f [<ffffffff81aee0fa>] mount_root+0x57/0x5b [<ffffffff81aee23b>] prepare_namespace+0x13d/0x176 [<ffffffff8107eec0>] ? release_tgcred.isra.4+0x330/0x30 [<ffffffff81aedd60>] kernel_init+0x155/0x15a [<ffffffff81087b97>] ? schedule_tail+0x27/0xb0 [<ffffffff815f4d24>] kernel_thread_helper+0x5/0x10 [<ffffffff81aedc0b>] ? start_kernel+0x3c5/0x3c5 [<ffffffff815f4d20>] ? 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 <tj@kernel.org> Reported-by: Szymon Gruszczynski <sz.gruszczynski@googlemail.com> Cc: Will Drewry <wad@chromium.org> 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) ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] block: fix buffer overflow when printing partition UUIDs 2012-05-14 21:03 ` [PATCH] block: fix buffer overflow when printing partition UUIDs Tejun Heo @ 2012-05-15 6:22 ` Jens Axboe 0 siblings, 0 replies; 3+ messages in thread From: Jens Axboe @ 2012-05-15 6:22 UTC (permalink / raw) To: Tejun Heo Cc: Dave Jones, Linux Kernel, Szymon Gruszczynski, Fedora Kernel Team, Al Viro On 05/14/2012 11:03 PM, Tejun Heo wrote: > 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 > > [<ffffffff815e226b>] panic+0xba/0x1c6 > [<ffffffff81b14c7e>] ? printk_all_partitions+0x259/0x26xb > [<ffffffff810566bb>] __stack_chk_fail+0x1b/0x20 > [<ffffffff81b15c7e>] printk_all_paritions+0x259/0x26xb > [<ffffffff81aedfe0>] mount_block_root+0x1bc/0x27f > [<ffffffff81aee0fa>] mount_root+0x57/0x5b > [<ffffffff81aee23b>] prepare_namespace+0x13d/0x176 > [<ffffffff8107eec0>] ? release_tgcred.isra.4+0x330/0x30 > [<ffffffff81aedd60>] kernel_init+0x155/0x15a > [<ffffffff81087b97>] ? schedule_tail+0x27/0xb0 > [<ffffffff815f4d24>] kernel_thread_helper+0x5/0x10 > [<ffffffff81aedc0b>] ? start_kernel+0x3c5/0x3c5 > [<ffffffff815f4d20>] ? gs_change+0x13/0x13 > > Increase the buffer size, remove the dangerous part_unpack_uuid() and > use snprintf() directly from printk_all_partitions(). Ooops, thanks Tejun, applied for current branch. -- Jens Axboe ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2012-05-15 6:22 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2012-05-09 19:58 stack overflow in printk_all_partitions Dave Jones 2012-05-14 21:03 ` [PATCH] block: fix buffer overflow when printing partition UUIDs Tejun Heo 2012-05-15 6:22 ` Jens Axboe
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