| Message ID | tencent_9E78266DF82CB96C549658EA5AED66CD240A@qq.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [V2] block: no show partitions if partno corrupted | expand |
On 1/14/25 1:51 AM, Edward Adam Davis wrote: > diff --git a/block/genhd.c b/block/genhd.c > index 9130e163e191..8d539a4a3b37 100644 > --- a/block/genhd.c > +++ b/block/genhd.c > @@ -890,7 +890,9 @@ static int show_partition(struct seq_file *seqf, void *v) > > rcu_read_lock(); > xa_for_each(&sgp->part_tbl, idx, part) { > - if (!bdev_nr_sectors(part)) > + int partno = bdev_partno(part); > + > + if (!bdev_nr_sectors(part) || WARN_ON(partno >= DISK_MAX_PARTS)) > continue; > seq_printf(seqf, "%4d %7d %10llu %pg\n", > MAJOR(part->bd_dev), MINOR(part->bd_dev), This should be a WARN_ON_ONCE(), and please put warn-on's on a separate line.
On 1/14/25 7:58 AM, Edward Adam Davis wrote: > diff --git a/block/genhd.c b/block/genhd.c > index 9130e163e191..3a9c36ad6bbd 100644 > --- a/block/genhd.c > +++ b/block/genhd.c > @@ -890,6 +890,9 @@ static int show_partition(struct seq_file *seqf, void *v) > > rcu_read_lock(); > xa_for_each(&sgp->part_tbl, idx, part) { > + int partno = bdev_partno(part); > + > + WARN_ON_ONCE(partno >= DISK_MAX_PARTS); > if (!bdev_nr_sectors(part)) > continue; > seq_printf(seqf, "%4d %7d %10llu %pg\n", Surely you still want to continue for that condition?
On Tue, 14 Jan 2025 08:02:15 -0700, Jens Axboe wrote: > > diff --git a/block/genhd.c b/block/genhd.c > > index 9130e163e191..3a9c36ad6bbd 100644 > > --- a/block/genhd.c > > +++ b/block/genhd.c > > @@ -890,6 +890,9 @@ static int show_partition(struct seq_file *seqf, void *v) > > > > rcu_read_lock(); > > xa_for_each(&sgp->part_tbl, idx, part) { > > + int partno = bdev_partno(part); > > + > > + WARN_ON_ONCE(partno >= DISK_MAX_PARTS); > > if (!bdev_nr_sectors(part)) > > continue; > > seq_printf(seqf, "%4d %7d %10llu %pg\n", > > Surely you still want to continue for that condition? No. But like following, ok? diff --git a/block/genhd.c b/block/genhd.c index 9130e163e191..142b13620f0c 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -890,7 +890,10 @@ static int show_partition(struct seq_file *seqf, void *v) rcu_read_lock(); xa_for_each(&sgp->part_tbl, idx, part) { - if (!bdev_nr_sectors(part)) + int partno = bdev_partno(part); + + WARN_ON_ONCE(partno >= DISK_MAX_PARTS); + if (!bdev_nr_sectors(part) || partno >= DISK_MAX_PARTS) continue; seq_printf(seqf, "%4d %7d %10llu %pg\n", MAJOR(part->bd_dev), MINOR(part->bd_dev),
On 1/14/25 8:15 AM, Edward Adam Davis wrote: > On Tue, 14 Jan 2025 08:02:15 -0700, Jens Axboe wrote: >>> diff --git a/block/genhd.c b/block/genhd.c >>> index 9130e163e191..3a9c36ad6bbd 100644 >>> --- a/block/genhd.c >>> +++ b/block/genhd.c >>> @@ -890,6 +890,9 @@ static int show_partition(struct seq_file *seqf, void *v) >>> >>> rcu_read_lock(); >>> xa_for_each(&sgp->part_tbl, idx, part) { >>> + int partno = bdev_partno(part); >>> + >>> + WARN_ON_ONCE(partno >= DISK_MAX_PARTS); >>> if (!bdev_nr_sectors(part)) >>> continue; >>> seq_printf(seqf, "%4d %7d %10llu %pg\n", >> >> Surely you still want to continue for that condition? > No. No? > But like following, ok? > diff --git a/block/genhd.c b/block/genhd.c > index 9130e163e191..142b13620f0c 100644 > --- a/block/genhd.c > +++ b/block/genhd.c > @@ -890,7 +890,10 @@ static int show_partition(struct seq_file *seqf, void *v) > > rcu_read_lock(); > xa_for_each(&sgp->part_tbl, idx, part) { > - if (!bdev_nr_sectors(part)) > + int partno = bdev_partno(part); > + > + WARN_ON_ONCE(partno >= DISK_MAX_PARTS); > + if (!bdev_nr_sectors(part) || partno >= DISK_MAX_PARTS) > continue; > seq_printf(seqf, "%4d %7d %10llu %pg\n", > MAJOR(part->bd_dev), MINOR(part->bd_dev), That's just silly... xa_for_each(&sgp->part_tbl, idx, part) { int partno = bdev_partno(part); if (!bdev_nr_sectors(part)) continue; if (WARN_ON_ONCE(partno >= DISK_MAX_PARTS)) continue; ... }
On Tue, 14 Jan 2025 08:25:13 -0700, Jens Axboe wrote: >> On Tue, 14 Jan 2025 08:02:15 -0700, Jens Axboe wrote: >>>> diff --git a/block/genhd.c b/block/genhd.c >>>> index 9130e163e191..3a9c36ad6bbd 100644 >>>> --- a/block/genhd.c >>>> +++ b/block/genhd.c >>>> @@ -890,6 +890,9 @@ static int show_partition(struct seq_file *seqf, void *v) >>>> >>>> rcu_read_lock(); >>>> xa_for_each(&sgp->part_tbl, idx, part) { >>>> + int partno = bdev_partno(part); >>>> + >>>> + WARN_ON_ONCE(partno >= DISK_MAX_PARTS); >>>> if (!bdev_nr_sectors(part)) >>>> continue; >>>> seq_printf(seqf, "%4d %7d %10llu %pg\n", >>> >>> Surely you still want to continue for that condition? >> No. > >No? > >> But like following, ok? >> diff --git a/block/genhd.c b/block/genhd.c >> index 9130e163e191..142b13620f0c 100644 >> --- a/block/genhd.c >> +++ b/block/genhd.c >> @@ -890,7 +890,10 @@ static int show_partition(struct seq_file *seqf, void *v) >> >> rcu_read_lock(); >> xa_for_each(&sgp->part_tbl, idx, part) { >> - if (!bdev_nr_sectors(part)) >> + int partno = bdev_partno(part); >> + >> + WARN_ON_ONCE(partno >= DISK_MAX_PARTS); >> + if (!bdev_nr_sectors(part) || partno >= DISK_MAX_PARTS) >> continue; >> seq_printf(seqf, "%4d %7d %10llu %pg\n", >> MAJOR(part->bd_dev), MINOR(part->bd_dev), > >That's just silly... I checked WARN_ON_ONCE(), and when the condition is met, the subsequent WARN_ON_ONCE() will still return true, so adding it will not affect the judgment of the condition. It just issues a warning the first time the condition is met, and it will still return true if the condition is true. > > xa_for_each(&sgp->part_tbl, idx, part) { > int partno = bdev_partno(part); > > if (!bdev_nr_sectors(part)) > continue; > if (WARN_ON_ONCE(partno >= DISK_MAX_PARTS)) > continue; > > ... > } Edward
On Tue, Jan 14, 2025 at 07:16:31AM -0700, Jens Axboe wrote: > On 1/14/25 1:51 AM, Edward Adam Davis wrote: > > diff --git a/block/genhd.c b/block/genhd.c > > index 9130e163e191..8d539a4a3b37 100644 > > --- a/block/genhd.c > > +++ b/block/genhd.c > > @@ -890,7 +890,9 @@ static int show_partition(struct seq_file *seqf, void *v) > > > > rcu_read_lock(); > > xa_for_each(&sgp->part_tbl, idx, part) { > > - if (!bdev_nr_sectors(part)) > > + int partno = bdev_partno(part); > > + > > + if (!bdev_nr_sectors(part) || WARN_ON(partno >= DISK_MAX_PARTS)) > > continue; > > seq_printf(seqf, "%4d %7d %10llu %pg\n", > > MAJOR(part->bd_dev), MINOR(part->bd_dev), > > This should be a WARN_ON_ONCE(), and please put warn-on's on a separate > line. Ummm... DISK_MAX_PARTS is 256. bdev_partno reads form bdev->__bd_flags and masks out BD_PARTNO, which is 255. In other words we should never be able to get a value bigger than 255 from bdev_partno, so something is really fishy here that a WARN_ON in the show function won't help with. Also the fact that the low-level printf code trips over a 8-bit integer sounds wrong, and if it does for something not caused by say a use after free higher up we've got another deep problem there. All of that has nothing to do with show_partition, though.
diff --git a/block/genhd.c b/block/genhd.c index 9130e163e191..8d539a4a3b37 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -890,7 +890,9 @@ static int show_partition(struct seq_file *seqf, void *v) rcu_read_lock(); xa_for_each(&sgp->part_tbl, idx, part) { - if (!bdev_nr_sectors(part)) + int partno = bdev_partno(part); + + if (!bdev_nr_sectors(part) || WARN_ON(partno >= DISK_MAX_PARTS)) continue; seq_printf(seqf, "%4d %7d %10llu %pg\n", MAJOR(part->bd_dev), MINOR(part->bd_dev),
syzbot reported a global-out-of-bounds in number. [1] Corrupted partno causes out-of-bounds access when accessing the hex_asc_upper array. To avoid this issue, skip partitions with partno greater than DISK_MAX_PARTS. [1] BUG: KASAN: global-out-of-bounds in number+0x3be/0xf40 lib/vsprintf.c:494 Read of size 1 at addr ffffffff8c5fc971 by task syz-executor351/5832 CPU: 0 UID: 0 PID: 5832 Comm: syz-executor351 Not tainted 6.13.0-rc6-next-20250107-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489 kasan_report+0x143/0x180 mm/kasan/report.c:602 number+0x3be/0xf40 lib/vsprintf.c:494 pointer+0x764/0x1210 lib/vsprintf.c:2484 vsnprintf+0x75a/0x1220 lib/vsprintf.c:2846 seq_vprintf fs/seq_file.c:391 [inline] seq_printf+0x172/0x270 fs/seq_file.c:406 show_partition+0x29f/0x3f0 block/genhd.c:905 seq_read_iter+0x969/0xd70 fs/seq_file.c:272 proc_reg_read_iter+0x1c2/0x290 fs/proc/inode.c:299 copy_splice_read+0x63a/0xb40 fs/splice.c:365 do_splice_read fs/splice.c:985 [inline] splice_direct_to_actor+0x4af/0xc80 fs/splice.c:1089 do_splice_direct_actor fs/splice.c:1207 [inline] do_splice_direct+0x289/0x3e0 fs/splice.c:1233 do_sendfile+0x564/0x8a0 fs/read_write.c:1363 __do_sys_sendfile64 fs/read_write.c:1424 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1410 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Reported-by: syzbot+fcee6b76cf2e261c51a4@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=fcee6b76cf2e261c51a4 Signed-off-by: Edward Adam Davis <eadavis@qq.com> --- V1 -> V2: Add a warning block/genhd.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)