syzbot


KASAN: slab-out-of-bounds Write in default_read_copy_kernel

Status: fixed on 2019/06/24 23:41
Subsystems: sound
[Documentation on labels]
Reported-by: syzbot+12f17c177de05efea72d@syzkaller.appspotmail.com
Fix commit: ca0214ee2802 ALSA: pcm: Fix possible OOB access in PCM oss plugins
First crash: 1995d, last: 1916d
Cause bisection: introduced by (bisect log) :
commit 65766ee0bf7fe8b3be80e2e1c3ef54ad59b29476
Author: Takashi Iwai <tiwai@suse.de>
Date: Fri Nov 9 10:59:45 2018 +0000

  ALSA: oss: Use kvzalloc() for local buffer allocations

Crash: KASAN: slab-out-of-bounds Write in default_read_copy_kernel (log)
Repro: C syz .config
  
Discussions (2)
Title Replies (including bot) Last reply
Reminder: 9 open syzbot bugs in sound subsystem 1 (1) 2019/06/24 05:07
KASAN: slab-out-of-bounds Write in default_read_copy_kernel 1 (3) 2019/03/19 13:35
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 KASAN: slab-out-of-bounds Write in default_read_copy_kernel syz error 2 1651d 1651d 0/1 auto-obsoleted due to no activity on 2022/08/26 17:20

Sample crash report:
RDX: 0000000000000001 RSI: 0000000020001640 RDI: 0000000000000003
RBP: 00000000006cf018 R08: 0000000000000001 R09: 0000000000000037
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: ffffffffffffffff R14: 0000000000000000 R15: 0000000000000000
==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:352 [inline]
BUG: KASAN: slab-out-of-bounds in default_read_copy_kernel+0xe1/0x140 sound/core/pcm_lib.c:1988
Write of size 64 at addr ffff8881cec699c0 by task syz-executor520/6056

CPU: 1 PID: 6056 Comm: syz-executor520 Not tainted 4.20.0-rc5+ #365
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+0x244/0x39d lib/dump_stack.c:113
 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 memcpy+0x37/0x50 mm/kasan/kasan.c:303
 memcpy include/linux/string.h:352 [inline]
 default_read_copy_kernel+0xe1/0x140 sound/core/pcm_lib.c:1988
 interleaved_copy+0xd1/0x110 sound/core/pcm_lib.c:2007
 __snd_pcm_lib_xfer+0x115f/0x1f23 sound/core/pcm_lib.c:2227
 snd_pcm_oss_read3+0x1c8/0x410 sound/core/oss/pcm_oss.c:1274
 io_capture_transfer+0x27d/0x310 sound/core/oss/io.c:73
 snd_pcm_plug_read_transfer+0x1d7/0x3b0 sound/core/oss/pcm_plugin.c:651
 snd_pcm_oss_read2+0x221/0x450 sound/core/oss/pcm_oss.c:1474
 snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1531 [inline]
 snd_pcm_oss_read+0x638/0x830 sound/core/oss/pcm_oss.c:2752
 do_loop_readv_writev fs/read_write.c:700 [inline]
 do_iter_read+0x4a3/0x650 fs/read_write.c:924
 vfs_readv+0x175/0x1c0 fs/read_write.c:986
 do_readv+0x11a/0x310 fs/read_write.c:1019
 __do_sys_readv fs/read_write.c:1106 [inline]
 __se_sys_readv fs/read_write.c:1103 [inline]
 __x64_sys_readv+0x75/0xb0 fs/read_write.c:1103
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x444079
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 7b d8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc8067a328 EFLAGS: 00000246 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444079
RDX: 0000000000000001 RSI: 0000000020001640 RDI: 0000000000000003
RBP: 00000000006cf018 R08: 0000000000000001 R09: 0000000000000037
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: ffffffffffffffff R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6056:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 __do_kmalloc_node mm/slab.c:3684 [inline]
 __kmalloc_node+0x50/0x70 mm/slab.c:3691
 kmalloc_node include/linux/slab.h:589 [inline]
 kvmalloc_node+0x65/0xf0 mm/util.c:416
 kvmalloc include/linux/mm.h:577 [inline]
 kvzalloc include/linux/mm.h:585 [inline]
 snd_pcm_plugin_alloc+0x577/0x770 sound/core/oss/pcm_plugin.c:70
 snd_pcm_plug_alloc+0x149/0x340 sound/core/oss/pcm_plugin.c:129
 snd_pcm_oss_change_params_locked+0x2209/0x3c60 sound/core/oss/pcm_oss.c:1038
 snd_pcm_oss_make_ready_locked+0xbc/0x130 sound/core/oss/pcm_oss.c:1183
 snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1507 [inline]
 snd_pcm_oss_read+0x417/0x830 sound/core/oss/pcm_oss.c:2752
 do_loop_readv_writev fs/read_write.c:700 [inline]
 do_iter_read+0x4a3/0x650 fs/read_write.c:924
 vfs_readv+0x175/0x1c0 fs/read_write.c:986
 do_readv+0x11a/0x310 fs/read_write.c:1019
 __do_sys_readv fs/read_write.c:1106 [inline]
 __se_sys_readv fs/read_write.c:1103 [inline]
 __x64_sys_readv+0x75/0xb0 fs/read_write.c:1103
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xcf/0x230 mm/slab.c:3817
 kzfree+0x28/0x30 mm/slab_common.c:1564
 aa_free_task_ctx security/apparmor/include/task.h:61 [inline]
 apparmor_task_free+0x13a/0x1e0 security/apparmor/lsm.c:95
 security_task_free+0x4a/0x80 security/security.c:1007
 __put_task_struct+0x195/0x620 kernel/fork.c:724
 put_task_struct include/linux/sched/task.h:96 [inline]
 delayed_put_task_struct+0x2ff/0x4c0 kernel/exit.c:181
 __rcu_reclaim kernel/rcu/rcu.h:240 [inline]
 rcu_do_batch kernel/rcu/tree.c:2437 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2716 [inline]
 rcu_process_callbacks+0x100a/0x1ac0 kernel/rcu/tree.c:2697
 __do_softirq+0x308/0xb7e kernel/softirq.c:292

The buggy address belongs to the object at ffff8881cec699c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8881cec699c0, ffff8881cec699e0)
The buggy address belongs to the page:
page:ffffea00073b1a40 count:1 mapcount:0 mapping:ffff8881da8001c0 index:0xffff8881cec69fc1
flags: 0x2fffc0000000200(slab)
raw: 02fffc0000000200 ffffea00073a3748 ffff8881da801248 ffff8881da8001c0
raw: ffff8881cec69fc1 ffff8881cec69000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881cec69880: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8881cec69900: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8881cec69980: fb fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
                                                       ^
 ffff8881cec69a00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8881cec69a80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/12/07 07:38 upstream abb8d6ecbd8f dcf836b1 .config console log report syz C ci-upstream-kasan-gce
2019/02/24 15:38 upstream e60b5f79bd75 7a06e792 .config console log report ci-upstream-kasan-gce-smack-root
2018/12/07 06:36 upstream abb8d6ecbd8f dcf836b1 .config console log report ci-upstream-kasan-gce
* Struck through repros no longer work on HEAD.