Re: [syzbot] KASAN: use-after-free Read in snd_pcm_oss_poll

From: syzbot
Date: Thu Jan 12 2023 - 16:15:22 EST

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In reply to: syzbot: "[syzbot] KASAN: use-after-free Read in snd_pcm_oss_poll"
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syzbot has found a reproducer for the following issue on:

HEAD commit: 0a093b2893c7 Add linux-next specific files for 20230112
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13948291480000
kernel config: https://syzkaller.appspot.com/x/.config?x=835f3591019836d5
dashboard link: https://syzkaller.appspot.com/bug?extid=ee73befabe68e7907adf
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=142c4d16480000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10129b5a480000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8111a570d6cb/disk-0a093b28.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ecc135b7fc9a/vmlinux-0a093b28.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ca8d73b446ea/bzImage-0a093b28.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ee73befabe68e7907adf@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: use-after-free in snd_pcm_oss_poll+0x91c/0xab0 sound/core/oss/pcm_oss.c:2849
Read of size 8 at addr ffff88801c509840 by task syz-executor364/5089

CPU: 0 PID: 5089 Comm: syz-executor364 Not tainted 6.2.0-rc3-next-20230112-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:306 [inline]
print_report+0x15e/0x45d mm/kasan/report.c:417
kasan_report+0xc0/0xf0 mm/kasan/report.c:517
snd_pcm_oss_poll+0x91c/0xab0 sound/core/oss/pcm_oss.c:2849
vfs_poll include/linux/poll.h:88 [inline]
io_poll_check_events io_uring/poll.c:279 [inline]
io_poll_task_func+0x3a6/0x1220 io_uring/poll.c:327
handle_tw_list+0xa8/0x460 io_uring/io_uring.c:1169
tctx_task_work+0x12e/0x530 io_uring/io_uring.c:1224
task_work_run+0x16f/0x270 kernel/task_work.c:179
get_signal+0x1c7/0x24f0 kernel/signal.c:2635
arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306
exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297
do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f4b05dee34b
Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
RSP: 002b:00007ffc30175fb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: fffffffffffffff7 RBX: 000000000000000c RCX: 00007f4b05dee34b
RDX: ffffffffffffffb8 RSI: 000000000000450e RDI: 000000000000000b
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007ffc30175fe8
R13: 00007f4b05eb7508 R14: 00007ffc30176000 R15: 0000000000000000
</TASK>

Allocated by task 5089:
kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:371 [inline]
____kasan_kmalloc mm/kasan/common.c:330 [inline]
__kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:380
kmalloc include/linux/slab.h:580 [inline]
kzalloc include/linux/slab.h:720 [inline]
snd_pcm_oss_open_file sound/core/oss/pcm_oss.c:2433 [inline]
snd_pcm_oss_open.part.0+0x558/0x1330 sound/core/oss/pcm_oss.c:2535
snd_pcm_oss_open+0x44/0x60 sound/core/oss/pcm_oss.c:2499
soundcore_open+0x452/0x620 sound/sound_core.c:593
chrdev_open+0x26a/0x770 fs/char_dev.c:414
do_dentry_open+0x6cc/0x13f0 fs/open.c:883
do_open fs/namei.c:3558 [inline]
path_openat+0x1bc1/0x2b40 fs/namei.c:3715
do_filp_open+0x1ba/0x410 fs/namei.c:3742
do_sys_openat2+0x16d/0x4c0 fs/open.c:1311
do_sys_open fs/open.c:1327 [inline]
__do_sys_openat fs/open.c:1343 [inline]
__se_sys_openat fs/open.c:1338 [inline]
__x64_sys_openat+0x143/0x1f0 fs/open.c:1338
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 5089:
kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
kasan_save_free_info+0x2e/0x40 mm/kasan/generic.c:518
____kasan_slab_free mm/kasan/common.c:236 [inline]
____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200
kasan_slab_free include/linux/kasan.h:162 [inline]
slab_free_hook mm/slub.c:1781 [inline]
slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1807
slab_free mm/slub.c:3787 [inline]
__kmem_cache_free+0xaf/0x2d0 mm/slub.c:3800
snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2415 [inline]
snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2405 [inline]
snd_pcm_oss_release+0x182/0x300 sound/core/oss/pcm_oss.c:2592
__fput+0x27c/0xa90 fs/file_table.c:321
task_work_run+0x16f/0x270 kernel/task_work.c:179
get_signal+0x1c7/0x24f0 kernel/signal.c:2635
arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306
exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297
do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff88801c509840
which belongs to the cache kmalloc-16 of size 16
The buggy address is located 0 bytes inside of
16-byte region [ffff88801c509840, ffff88801c509850)

The buggy address belongs to the physical page:
page:ffffea0000714240 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1c509
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffff8880124413c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080800080 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, tgid 1 (swapper/0), ts 12562219376, free_ts 12549200446
prep_new_page mm/page_alloc.c:2549 [inline]
get_page_from_freelist+0x11bb/0x2d50 mm/page_alloc.c:4324
__alloc_pages+0x1cb/0x5c0 mm/page_alloc.c:5590
alloc_page_interleave+0x1e/0x200 mm/mempolicy.c:2114
alloc_pages+0x233/0x270 mm/mempolicy.c:2276
alloc_slab_page mm/slub.c:1851 [inline]
allocate_slab+0x25f/0x350 mm/slub.c:1998
new_slab mm/slub.c:2051 [inline]
___slab_alloc+0xa91/0x1400 mm/slub.c:3193
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3292
__slab_alloc_node mm/slub.c:3345 [inline]
slab_alloc_node mm/slub.c:3442 [inline]
__kmem_cache_alloc_node+0x136/0x330 mm/slub.c:3491
__do_kmalloc_node mm/slab_common.c:966 [inline]
__kmalloc+0x4a/0xd0 mm/slab_common.c:980
kmalloc include/linux/slab.h:584 [inline]
kzalloc include/linux/slab.h:720 [inline]
kobject_get_path+0xc2/0x230 lib/kobject.c:147
kobject_uevent_env+0x257/0x1620 lib/kobject_uevent.c:529
kernel_add_sysfs_param kernel/params.c:816 [inline]
param_sysfs_builtin kernel/params.c:851 [inline]
param_sysfs_builtin_init+0x321/0x3fd kernel/params.c:985
do_one_initcall+0x141/0x7d0 init/main.c:1306
do_initcall_level init/main.c:1379 [inline]
do_initcalls init/main.c:1395 [inline]
do_basic_setup init/main.c:1414 [inline]
kernel_init_freeable+0x6f9/0x782 init/main.c:1634
kernel_init+0x1e/0x1d0 init/main.c:1522
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1451 [inline]
free_pcp_prepare+0x4d0/0x910 mm/page_alloc.c:1501
free_unref_page_prepare mm/page_alloc.c:3387 [inline]
free_unref_page+0x1d/0x490 mm/page_alloc.c:3482
kasan_depopulate_vmalloc_pte+0x60/0x80 mm/kasan/shadow.c:372
apply_to_pte_range mm/memory.c:2575 [inline]
apply_to_pmd_range mm/memory.c:2619 [inline]
apply_to_pud_range mm/memory.c:2655 [inline]
apply_to_p4d_range mm/memory.c:2691 [inline]
__apply_to_page_range+0x68c/0x1030 mm/memory.c:2725
kasan_release_vmalloc+0xab/0xc0 mm/kasan/shadow.c:486
__purge_vmap_area_lazy+0x897/0x1fa0 mm/vmalloc.c:1776
drain_vmap_area_work+0x56/0xe0 mm/vmalloc.c:1809
process_one_work+0x9bf/0x1750 kernel/workqueue.c:2293
worker_thread+0x669/0x1090 kernel/workqueue.c:2440
kthread+0x2e8/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Memory state around the buggy address:
ffff88801c509700: 00 03 fc fc 00 00 fc fc 00 03 fc fc 00 03 fc fc
ffff88801c509780: 00 00 fc fc fb fb fc fc fb fb fc fc fb fb fc fc
>ffff88801c509800: 00 01 fc fc 00 01 fc fc fa fb fc fc 00 03 fc fc
^
ffff88801c509880: 00 03 fc fc fa fb fc fc 00 00 fc fc 00 00 fc fc
ffff88801c509900: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
==================================================================

Next message: Nícolas F. R. A. Prado: "Re: [PATCH v7, 5/7] media: mediatek: vcodec: Different codec using different capture format"
Previous message: Ian Rogers: "Re: [PATCH v3 1/3] objtool: Install libsubcmd in build"
In reply to: syzbot: "[syzbot] KASAN: use-after-free Read in snd_pcm_oss_poll"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]