KASAN: use-after-free Read in delete_and_unsubscribe_port (2)

Status: fixed on 2020/09/16 22:51
Subsystems: sound
[Documentation on labels]
Reported-by: syzbot+1a54a94bd32716796edd@syzkaller.appspotmail.com
Fix commit: 80982c7e834e ALSA: seq: oss: Serialize ioctls
First crash: 2212d, last: 2182d
Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: WARNING in sysfs_warn_dup (log)
Repro: syz .config
  
▶ ▼ Discussions (9)
Title Replies (including bot) Last reply
[PATCH 4.4 000/149] 4.4.233-rc1 review 163 (163) 2020/10/31 20:04
[PATCH 4.9 000/212] 4.9.233-rc1 review 220 (220) 2020/08/21 09:40
[PATCH 4.14 000/228] 4.14.194-rc1 review 234 (234) 2020/08/21 06:59
[PATCH 4.19 00/48] 4.19.139-rc1 review 61 (61) 2020/08/11 16:45
[PATCH 5.8 00/38] 5.8.1-rc1 review 46 (46) 2020/08/11 16:20
[PATCH 5.7 00/79] 5.7.15-rc1 review 83 (83) 2020/08/11 14:23
[PATCH 5.4 00/67] 5.4.58-rc1 review 71 (71) 2020/08/11 14:23
[PATCH] ALSA: seq: KASAN: use-after-free Read in delete_and_unsubscribe_port 5 (5) 2020/08/03 09:44
KASAN: use-after-free Read in delete_and_unsubscribe_port (2) 1 (3) 2020/07/30 04:50
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in delete_and_unsubscribe_port sound 19 1 2770d 2765d 0/29 auto-closed as invalid on 2019/06/23 16:41
linux-4.14 KASAN: use-after-free Read in delete_and_unsubscribe_port 19 syz done 2 2187d 2187d 1/1 fixed on 2020/09/01 18:34
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2020/08/04 12:07 16m tiwai@suse.de git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git test/seq-oss-serialize OK

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in list_empty include/linux/list.h:282 [inline]
BUG: KASAN: use-after-free in delete_and_unsubscribe_port+0x8b/0x450 sound/core/seq/seq_ports.c:530
Read of size 8 at addr ffff88809f60ea60 by task syz-executor.0/7212

CPU: 1 PID: 7212 Comm: syz-executor.0 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1f0/0x31e lib/dump_stack.c:118
 print_address_description+0x66/0x5a0 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 list_empty include/linux/list.h:282 [inline]
 delete_and_unsubscribe_port+0x8b/0x450 sound/core/seq/seq_ports.c:530
 snd_seq_port_disconnect+0x568/0x610 sound/core/seq/seq_ports.c:612
 snd_seq_ioctl_unsubscribe_port+0x349/0x6c0 sound/core/seq/seq_clientmgr.c:1525
 snd_seq_oss_midi_close+0x397/0x620 sound/core/seq/oss/seq_oss_midi.c:405
 snd_seq_oss_synth_reset+0x335/0x8b0 sound/core/seq/oss/seq_oss_synth.c:406
 snd_seq_oss_reset+0x5b/0x250 sound/core/seq/oss/seq_oss_init.c:435
 snd_seq_oss_ioctl+0x5c2/0x1090 sound/core/seq/oss/seq_oss_ioctl.c:93
 odev_ioctl+0x51/0x70 sound/core/seq/oss/seq_oss.c:174
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl fs/ioctl.c:753 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:760
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c429
Code: 8d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f9cfb928c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000000154c0 RCX: 000000000045c429
RDX: 0000000000000000 RSI: 0000000000005100 RDI: 0000000000000003
RBP: 000000000078bfd8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bfac
R13: 00007fff5f38710f R14: 00007f9cfb9299c0 R15: 000000000078bfac

Allocated by task 7211:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
 kmem_cache_alloc_trace+0x234/0x300 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 snd_seq_port_connect+0x66/0x460 sound/core/seq/seq_ports.c:553
 snd_seq_ioctl_subscribe_port+0x349/0x6c0 sound/core/seq/seq_clientmgr.c:1484
 snd_seq_oss_midi_open+0x4db/0x830 sound/core/seq/oss/seq_oss_midi.c:364
 snd_seq_oss_synth_setup_midi+0x108/0x510 sound/core/seq/oss/seq_oss_synth.c:269
 snd_seq_oss_open+0x899/0xe90 sound/core/seq/oss/seq_oss_init.c:261
 odev_open+0x5e/0x90 sound/core/seq/oss/seq_oss.c:125
 chrdev_open+0x498/0x580 fs/char_dev.c:414
 do_dentry_open+0x813/0x1070 fs/open.c:828
 do_open fs/namei.c:3243 [inline]
 path_openat+0x278d/0x37f0 fs/namei.c:3360
 do_filp_open+0x191/0x3a0 fs/namei.c:3387
 do_sys_openat2+0x463/0x770 fs/open.c:1179
 do_sys_open fs/open.c:1195 [inline]
 __do_sys_openat fs/open.c:1209 [inline]
 __se_sys_openat fs/open.c:1204 [inline]
 __x64_sys_openat+0x1c8/0x1f0 fs/open.c:1204
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 7211:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 snd_seq_port_disconnect+0x570/0x610 sound/core/seq/seq_ports.c:614
 snd_seq_ioctl_unsubscribe_port+0x349/0x6c0 sound/core/seq/seq_clientmgr.c:1525
 snd_seq_oss_midi_close+0x397/0x620 sound/core/seq/oss/seq_oss_midi.c:405
 snd_seq_oss_synth_reset+0x335/0x8b0 sound/core/seq/oss/seq_oss_synth.c:406
 snd_seq_oss_reset+0x5b/0x250 sound/core/seq/oss/seq_oss_init.c:435
 snd_seq_oss_ioctl+0x5c2/0x1090 sound/core/seq/oss/seq_oss_ioctl.c:93
 odev_ioctl+0x51/0x70 sound/core/seq/oss/seq_oss.c:174
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl fs/ioctl.c:753 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:760
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88809f60ea00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 96 bytes inside of
 128-byte region [ffff88809f60ea00, ffff88809f60ea80)
The buggy address belongs to the page:
page:ffffea00027d8380 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00027dc508 ffff8880aa401550 ffff8880aa400700
raw: 0000000000000000 ffff88809f60e000 0000000100000010 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809f60e900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
 ffff88809f60e980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809f60ea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff88809f60ea80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809f60eb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/07/30 04:10 upstream d3590ebf6f91 233283a1 .config console log report syz ci-upstream-kasan-gce-smack-root
2020/07/30 03:32 upstream d3590ebf6f91 233283a1 .config console log report syz ci-upstream-kasan-gce-smack-root
2020/08/03 23:25 linux-next 01830e6c042e 196277c4 .config console log report syz ci-upstream-linux-next-kasan-gce-root
2020/07/04 22:42 upstream 7cc2a8ea1048 51095195 .config console log report ci-upstream-kasan-gce-386
* Struck through repros no longer work on HEAD.