syzbot


KASAN: slab-use-after-free Read in slip_open (2)

Status: moderation: reported on 2024/04/29 07:50
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+d72b9ee22d047a72b38d@syzkaller.appspotmail.com
First crash: 51d, last: 51d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in slip_open net 2 414d 427d 0/27 auto-obsoleted due to no activity on 2023/08/05 06:52
linux-6.1 KASAN: use-after-free Read in slip_open 1 369d 369d 0/3 auto-obsoleted due to no activity on 2023/09/20 09:40
upstream KASAN: use-after-free Read in slip_open (2) net 4 610d 763d 0/27 auto-obsoleted due to no activity on 2023/02/11 15:10

Sample crash report:
BUG: KASAN: slab-use-after-free in sl_sync drivers/net/slip/slip.c:730 [inline]
BUG: KASAN: slab-use-after-free in slip_open+0xea1/0x1140 drivers/net/slip/slip.c:806
Read of size 1 at addr ffff888060f14d91 by task syz-executor.2/6548

CPU: 0 PID: 6548 Comm: syz-executor.2 Not tainted 6.9.0-rc5-syzkaller-00042-ge88c4cfcb7b8 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 sl_sync drivers/net/slip/slip.c:730 [inline]
 slip_open+0xea1/0x1140 drivers/net/slip/slip.c:806
 tty_ldisc_open+0x9c/0x120 drivers/tty/tty_ldisc.c:432
 tty_set_ldisc+0x2e6/0x680 drivers/tty/tty_ldisc.c:557
 tiocsetd drivers/tty/tty_io.c:2439 [inline]
 tty_ioctl+0xc2e/0x15f0 drivers/tty/tty_io.c:2739
 tty_compat_ioctl+0x25c/0x4f0 drivers/tty/tty_io.c:2953
 __do_compat_sys_ioctl+0x2c3/0x330 fs/ioctl.c:1004
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf725b579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f5e4d5ac EFLAGS: 00000292 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000005423
RDX: 0000000020000040 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 6539:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slub.c:3966 [inline]
 __kmalloc_node+0x226/0x480 mm/slub.c:3973
 kmalloc_node include/linux/slab.h:648 [inline]
 kvmalloc_node+0x9d/0x1a0 mm/util.c:634
 kvmalloc include/linux/slab.h:766 [inline]
 kvzalloc include/linux/slab.h:774 [inline]
 alloc_netdev_mqs+0xb3/0x1260 net/core/dev.c:10849
 sl_alloc drivers/net/slip/slip.c:756 [inline]
 slip_open+0x35d/0x1140 drivers/net/slip/slip.c:817
 tty_ldisc_open+0x9c/0x120 drivers/tty/tty_ldisc.c:432
 tty_set_ldisc+0x2e6/0x680 drivers/tty/tty_ldisc.c:557
 tiocsetd drivers/tty/tty_io.c:2439 [inline]
 tty_ioctl+0xc2e/0x15f0 drivers/tty/tty_io.c:2739
 tty_compat_ioctl+0x25c/0x4f0 drivers/tty/tty_io.c:2953
 __do_compat_sys_ioctl+0x2c3/0x330 fs/ioctl.c:1004
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Freed by task 6538:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
 poison_slab_object mm/kasan/common.c:240 [inline]
 __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2106 [inline]
 slab_free mm/slub.c:4280 [inline]
 kfree+0x129/0x390 mm/slub.c:4390
 kvfree+0x47/0x50 mm/util.c:680
 device_release+0xa1/0x240 drivers/base/core.c:2580
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1fa/0x5b0 lib/kobject.c:737
 netdev_run_todo+0x7d1/0x1260 net/core/dev.c:10600
 slip_close+0x165/0x1c0 drivers/net/slip/slip.c:906
 tty_ldisc_close+0x111/0x1a0 drivers/tty/tty_ldisc.c:455
 tty_ldisc_kill+0x8e/0x150 drivers/tty/tty_ldisc.c:607
 tty_ldisc_release+0x116/0x2a0 drivers/tty/tty_ldisc.c:775
 tty_release_struct+0x23/0xe0 drivers/tty/tty_io.c:1696
 tty_release+0xe33/0x1420 drivers/tty/tty_io.c:1867
 __fput+0x270/0xb80 fs/file_table.c:422
 __fput_sync+0x47/0x50 fs/file_table.c:507
 __do_sys_close fs/open.c:1556 [inline]
 __se_sys_close fs/open.c:1541 [inline]
 __ia32_sys_close+0x86/0x100 fs/open.c:1541
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

The buggy address belongs to the object at ffff888060f14000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 3473 bytes inside of
 freed 4096-byte region [ffff888060f14000, ffff888060f15000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x60f10
head: order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888062fc1b81
ksm flags: 0x4fff80000000840(slab|head|node=1|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 04fff80000000840 ffff888014c50280 ffffea0001781000 0000000000000003
raw: 0000000000000000 0000000080040004 00000001ffffffff ffff888062fc1b81
head: 04fff80000000840 ffff888014c50280 ffffea0001781000 0000000000000003
head: 0000000000000000 0000000080040004 00000001ffffffff ffff888062fc1b81
head: 04fff80000000003 ffffea000183c401 dead000000000122 00000000ffffffff
head: 0000000800000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 4691, tgid 1247449937 (udevd), ts 4691, free_ts 61356039317
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3317
 __alloc_pages+0x22b/0x2460 mm/page_alloc.c:4575
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page mm/slub.c:2175 [inline]
 allocate_slab mm/slub.c:2338 [inline]
 new_slab+0xcc/0x3a0 mm/slub.c:2391
 ___slab_alloc+0x670/0x16d0 mm/slub.c:3525
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3610
 __slab_alloc_node mm/slub.c:3663 [inline]
 slab_alloc_node mm/slub.c:3835 [inline]
 __do_kmalloc_node mm/slub.c:3965 [inline]
 __kmalloc_node+0x36e/0x480 mm/slub.c:3973
 kmalloc_node include/linux/slab.h:648 [inline]
 kvmalloc_node+0x9d/0x1a0 mm/util.c:634
 kvmalloc include/linux/slab.h:766 [inline]
 seq_buf_alloc fs/seq_file.c:38 [inline]
 seq_read_iter+0x830/0x12c0 fs/seq_file.c:210
 kernfs_fop_read_iter+0x41a/0x590 fs/kernfs/file.c:279
 call_read_iter include/linux/fs.h:2104 [inline]
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0x6c0/0xb80 fs/read_write.c:476
 ksys_read+0x12f/0x260 fs/read_write.c:619
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4691 tgid 4691 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1141 [inline]
 free_unref_page_prepare+0x527/0xb10 mm/page_alloc.c:2347
 free_unref_page+0x33/0x3c0 mm/page_alloc.c:2487
 __put_partials+0x14c/0x170 mm/slub.c:2906
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3798 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 __do_kmalloc_node mm/slub.c:3965 [inline]
 __kmalloc+0x1bd/0x440 mm/slub.c:3979
 kmalloc include/linux/slab.h:632 [inline]
 kzalloc include/linux/slab.h:749 [inline]
 tomoyo_encode2+0x100/0x3e0 security/tomoyo/realpath.c:45
 tomoyo_encode security/tomoyo/realpath.c:80 [inline]
 tomoyo_realpath_from_path+0x1a7/0x710 security/tomoyo/realpath.c:283
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x2a7/0x3b0 security/tomoyo/file.c:771
 tomoyo_file_open+0x71/0x90 security/tomoyo/tomoyo.c:334
 security_file_open+0x78/0x630 security/security.c:2961
 do_dentry_open+0x583/0x18c0 fs/open.c:942
 do_open fs/namei.c:3642 [inline]
 path_openat+0x1dfb/0x2990 fs/namei.c:3799
 do_filp_open+0x1dc/0x430 fs/namei.c:3826
 do_sys_openat2+0x17a/0x1e0 fs/open.c:1406

Memory state around the buggy address:
 ffff888060f14c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888060f14d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888060f14d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888060f14e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888060f14e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	10 06                	adc    %al,(%rsi)
   2:	03 74 b4 01          	add    0x1(%rsp,%rsi,4),%esi
   6:	10 07                	adc    %al,(%rdi)
   8:	03 74 b0 01          	add    0x1(%rax,%rsi,4),%esi
   c:	10 08                	adc    %cl,(%rax)
   e:	03 74 d8 01          	add    0x1(%rax,%rbx,8),%esi
  1e:	00 51 52             	add    %dl,0x52(%rcx)
  21:	55                   	push   %rbp
  22:	89 e5                	mov    %esp,%ebp
  24:	0f 34                	sysenter
  26:	cd 80                	int    $0x80
* 28:	5d                   	pop    %rbp <-- trapping instruction
  29:	5a                   	pop    %rdx
  2a:	59                   	pop    %rcx
  2b:	c3                   	ret
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	90                   	nop
  2f:	90                   	nop
  30:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
  37:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/25 07:45 upstream e88c4cfcb7b8 8bdc0f22 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: slab-use-after-free Read in slip_open
* Struck through repros no longer work on HEAD.