KASAN: use-after-free Read in free_netdev

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 017d67e9 ANDROID: CC_FLAGS_CFI add -fno-sanitize-blacklist
git tree: android-5.4
console output: https://syzkaller.appspot.com/x/log.txt?x=132a7145e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=3f89e7b19e996a7b
dashboard link: https://syzkaller.appspot.com/bug?extid=04649b68561aae62c5ff
compiler: Android (6032204 based on r370808) clang version 10.0.1 (https://android.googlesource.com/toolchain/llvm-project 6e765c10313d15c02ab29977a82938f66742c3a9)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+04649b...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in free_netdev+0x186/0x300 net/core/dev.c:9582
Read of size 8 at addr ffff8881c92b84f0 by task syz-executor.3/12731

CPU: 0 PID: 12731 Comm: syz-executor.3 Not tainted 5.4.24-syzkaller-00161-g017d67e9a8b3 #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+0x1b0/0x228 lib/dump_stack.c:118
print_address_description+0x96/0x5d0 mm/kasan/report.c:374
__kasan_report+0x14b/0x1c0 mm/kasan/report.c:506
kasan_report+0x26/0x50 mm/kasan/common.c:634
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
free_netdev+0x186/0x300 net/core/dev.c:9582
netdev_run_todo+0xbc4/0xe00 net/core/dev.c:9333
rtnl_unlock net/core/rtnetlink.c:112 [inline]
rtnetlink_rcv_msg+0x963/0xc20 net/core/rtnetlink.c:5255
netlink_rcv_skb+0x1f0/0x460 net/netlink/af_netlink.c:2478
rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5272
netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
netlink_unicast+0x87c/0xa20 net/netlink/af_netlink.c:1329
netlink_sendmsg+0x9a7/0xd40 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:638 [inline]
sock_sendmsg net/socket.c:658 [inline]
____sys_sendmsg+0x56f/0x860 net/socket.c:2298
___sys_sendmsg net/socket.c:2352 [inline]
__sys_sendmsg+0x26a/0x350 net/socket.c:2398
__do_sys_sendmsg net/socket.c:2407 [inline]
__se_sys_sendmsg net/socket.c:2405 [inline]
__x64_sys_sendmsg+0x7f/0x90 net/socket.c:2405
do_syscall_64+0xc0/0x100 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c479
Code: ad 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ff27a152c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff27a1536d4 RCX: 000000000045c479
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000005
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000007
R13: 00000000000009f9 R14: 00000000004cc71a R15: 0000000000000002

Allocated by task 12731:
save_stack mm/kasan/common.c:69 [inline]
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc+0x117/0x1b0 mm/kasan/common.c:510
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
__kmalloc+0x102/0x310 mm/slub.c:3802
kmalloc include/linux/slab.h:561 [inline]
sk_prot_alloc+0x11c/0x2f0 net/core/sock.c:1605
sk_alloc+0x35/0x300 net/core/sock.c:1659
tun_chr_open+0x7b/0x4a0 drivers/net/tun.c:3416
misc_open+0x3ea/0x440 drivers/char/misc.c:141
chrdev_open+0x60a/0x670 fs/char_dev.c:414
do_dentry_open+0x8f7/0x1070 fs/open.c:809
vfs_open+0x73/0x80 fs/open.c:926
do_last fs/namei.c:3528 [inline]
path_openat+0x1681/0x42d0 fs/namei.c:3646
do_filp_open+0x1f7/0x430 fs/namei.c:3676
do_sys_open+0x36f/0x7a0 fs/open.c:1109
__do_sys_openat fs/open.c:1136 [inline]
__se_sys_openat fs/open.c:1130 [inline]
__x64_sys_openat+0xa2/0xb0 fs/open.c:1130
do_syscall_64+0xc0/0x100 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 12728:
save_stack mm/kasan/common.c:69 [inline]
set_track mm/kasan/common.c:77 [inline]
kasan_set_free_info mm/kasan/common.c:332 [inline]
__kasan_slab_free+0x168/0x220 mm/kasan/common.c:471
kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
slab_free_hook mm/slub.c:1424 [inline]
slab_free_freelist_hook mm/slub.c:1457 [inline]
slab_free mm/slub.c:3004 [inline]
kfree+0x170/0x6d0 mm/slub.c:3956
sk_prot_free net/core/sock.c:1642 [inline]
__sk_destruct+0x45f/0x4e0 net/core/sock.c:1726
sk_destruct net/core/sock.c:1741 [inline]
__sk_free+0x35d/0x430 net/core/sock.c:1752
sk_free+0x45/0x50 net/core/sock.c:1763
sock_put include/net/sock.h:1735 [inline]
__tun_detach+0x15d0/0x1a40 drivers/net/tun.c:728
tun_detach drivers/net/tun.c:740 [inline]
tun_chr_close+0xb8/0xd0 drivers/net/tun.c:3452
__fput+0x295/0x710 fs/file_table.c:280
____fput+0x15/0x20 fs/file_table.c:313
task_work_run+0x176/0x1a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop arch/x86/entry/common.c:163 [inline]
prepare_exit_to_usermode+0x2d8/0x370 arch/x86/entry/common.c:194
syscall_return_slowpath+0x6f/0x500 arch/x86/entry/common.c:274
do_syscall_64+0xe8/0x100 arch/x86/entry/common.c:300
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8881c92b8000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1264 bytes inside of
2048-byte region [ffff8881c92b8000, ffff8881c92b8800)
The buggy address belongs to the page:
page:ffffea000724ae00 refcount:1 mapcount:0 mapping:ffff8881da802800 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 ffffea00072ff600 0000000200000002 ffff8881da802800
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881c92b8380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881c92b8400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881c92b8480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881c92b8500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881c92b8580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: 017d67e9 ANDROID: CC_FLAGS_CFI add -fno-sanitize-blacklist
git tree: android-5.4

console output: https://syzkaller.appspot.com/x/log.txt?x=17884f31e00000

kernel config: https://syzkaller.appspot.com/x/.config?x=3f89e7b19e996a7b
dashboard link: https://syzkaller.appspot.com/bug?extid=04649b68561aae62c5ff
compiler: Android (6032204 based on r370808) clang version 10.0.1 (https://android.googlesource.com/toolchain/llvm-project 6e765c10313d15c02ab29977a82938f66742c3a9)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1384481de00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+04649b...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in free_netdev+0x186/0x300 net/core/dev.c:9582

Read of size 8 at addr ffff8881d4ec74f0 by task syz-executor.0/4543

CPU: 0 PID: 4543 Comm: syz-executor.0 Not tainted 5.4.24-syzkaller-00161-g017d67e9a8b3 #0

RSP: 002b:00007f9e32fcbc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f9e32fcc6d4 RCX: 000000000045c479

RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000005

RBP: 000000000076bfc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009f9 R14: 00000000004cc71a R15: 000000000076bfcc

Allocated by task 4532:

save_stack mm/kasan/common.c:69 [inline]
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc+0x117/0x1b0 mm/kasan/common.c:510
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
__kmalloc+0x102/0x310 mm/slub.c:3802
kmalloc include/linux/slab.h:561 [inline]
sk_prot_alloc+0x11c/0x2f0 net/core/sock.c:1605
sk_alloc+0x35/0x300 net/core/sock.c:1659
tun_chr_open+0x7b/0x4a0 drivers/net/tun.c:3416
misc_open+0x3ea/0x440 drivers/char/misc.c:141
chrdev_open+0x60a/0x670 fs/char_dev.c:414
do_dentry_open+0x8f7/0x1070 fs/open.c:809
vfs_open+0x73/0x80 fs/open.c:926
do_last fs/namei.c:3528 [inline]
path_openat+0x1681/0x42d0 fs/namei.c:3646
do_filp_open+0x1f7/0x430 fs/namei.c:3676
do_sys_open+0x36f/0x7a0 fs/open.c:1109
__do_sys_openat fs/open.c:1136 [inline]
__se_sys_openat fs/open.c:1130 [inline]
__x64_sys_openat+0xa2/0xb0 fs/open.c:1130
do_syscall_64+0xc0/0x100 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 4531:

The buggy address belongs to the object at ffff8881d4ec7000

which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1264 bytes inside of

2048-byte region [ffff8881d4ec7000, ffff8881d4ec7800)

The buggy address belongs to the page:

page:ffffea000753b000 refcount:1 mapcount:0 mapping:ffff8881da802800 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881da802800

raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff8881d4ec7380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d4ec7400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881d4ec7480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881d4ec7500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d4ec7580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: 3334f0da FROMGIT: driver core: Reevaluate dev->links.need_..
git tree: android-5.4
console output: https://syzkaller.appspot.com/x/log.txt?x=17c6b731e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=2425845ca84241a0

dashboard link: https://syzkaller.appspot.com/bug?extid=04649b68561aae62c5ff
compiler: Android (6032204 based on r370808) clang version 10.0.1 (https://android.googlesource.com/toolchain/llvm-project 6e765c10313d15c02ab29977a82938f66742c3a9)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17aeee2de00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=101a5181e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+04649b...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in free_netdev+0x186/0x300 net/core/dev.c:9582

Read of size 8 at addr ffff8881cdaf54f0 by task syz-executor878/2020

CPU: 1 PID: 2020 Comm: syz-executor878 Not tainted 5.4.24-syzkaller-00181-g3334f0da669e #0

RIP: 0033:0x4483b9
Code: e8 ac e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 4b 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f11fb1cbd98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000006e3a28 RCX: 00000000004483b9

RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000005

RBP: 00000000006e3a20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006e3a2c
R13: 0000003065736f72 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 2020:

save_stack mm/kasan/common.c:69 [inline]
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc+0x117/0x1b0 mm/kasan/common.c:510
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
__kmalloc+0x102/0x310 mm/slub.c:3802
kmalloc include/linux/slab.h:561 [inline]
sk_prot_alloc+0x11c/0x2f0 net/core/sock.c:1605
sk_alloc+0x35/0x300 net/core/sock.c:1659
tun_chr_open+0x7b/0x4a0 drivers/net/tun.c:3416
misc_open+0x3ea/0x440 drivers/char/misc.c:141
chrdev_open+0x60a/0x670 fs/char_dev.c:414
do_dentry_open+0x8f7/0x1070 fs/open.c:809
vfs_open+0x73/0x80 fs/open.c:926
do_last fs/namei.c:3528 [inline]
path_openat+0x1681/0x42d0 fs/namei.c:3646
do_filp_open+0x1f7/0x430 fs/namei.c:3676
do_sys_open+0x36f/0x7a0 fs/open.c:1109
__do_sys_openat fs/open.c:1136 [inline]
__se_sys_openat fs/open.c:1130 [inline]
__x64_sys_openat+0xa2/0xb0 fs/open.c:1130
do_syscall_64+0xc0/0x100 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 2019:

The buggy address belongs to the object at ffff8881cdaf5000

which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1264 bytes inside of

2048-byte region [ffff8881cdaf5000, ffff8881cdaf5800)

The buggy address belongs to the page:

page:ffffea000736bc00 refcount:1 mapcount:0 mapping:ffff8881da802800 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881da802800

raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff8881cdaf5380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881cdaf5400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881cdaf5480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881cdaf5500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881cdaf5580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.