syzbot


KASAN: use-after-free Read in alloc_netdev_mqs

Status: fixed on 2020/04/15 17:19
Subsystems: net
[Documentation on labels]
Fix commit: e08ad80551b4 net: add strict checks in netdev_name_node_alt_destroy()
First crash: 1585d, last: 1585d

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:199 [inline]
BUG: KASAN: use-after-free in lockdep_register_key+0x3b9/0x490 kernel/locking/lockdep.c:1126
Read of size 8 at addr ffff88805005cb48 by task syz-executor.4/26857

CPU: 1 PID: 26857 Comm: syz-executor.4 Not tainted 5.6.0-rc1-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+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:641
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 __read_once_size include/linux/compiler.h:199 [inline]
 lockdep_register_key+0x3b9/0x490 kernel/locking/lockdep.c:1126
 netdev_register_lockdep_key net/core/dev.c:9241 [inline]
 alloc_netdev_mqs+0x1b7/0xe40 net/core/dev.c:9816
 rtnl_create_link+0x22d/0xaf0 net/core/rtnetlink.c:3047
 veth_newlink+0x24b/0xa60 drivers/net/veth.c:1269
 __rtnl_newlink+0x109d/0x1790 net/core/rtnetlink.c:3319
 rtnl_newlink+0x69/0xa0 net/core/rtnetlink.c:3377
 rtnetlink_rcv_msg+0x45e/0xaf0 net/core/rtnetlink.c:5438
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5456
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:672
 ____sys_sendmsg+0x753/0x880 net/socket.c:2343
 ___sys_sendmsg+0x100/0x170 net/socket.c:2397
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2430
 __do_sys_sendmsg net/socket.c:2439 [inline]
 __se_sys_sendmsg net/socket.c:2437 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c6c9
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:00007f26d138fc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f26d13906d4 RCX: 000000000045c6c9
RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000005
RBP: 000000000076bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009cb R14: 00000000004cc6fd R15: 000000000076bfd4

Allocated by task 23927:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:515 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x163/0x770 mm/slab.c:3665
 kmalloc include/linux/slab.h:560 [inline]
 tomoyo_realpath_from_path+0xc5/0x660 security/tomoyo/realpath.c:252
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_number_perm+0x1dd/0x520 security/tomoyo/file.c:723
 tomoyo_file_ioctl+0x23/0x30 security/tomoyo/tomoyo.c:335
 security_file_ioctl+0x77/0xc0 security/security.c:1441
 ksys_ioctl+0x56/0x180 fs/ioctl.c:757
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:770
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 23927:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3757
 tomoyo_realpath_from_path+0x1a7/0x660 security/tomoyo/realpath.c:289
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_number_perm+0x1dd/0x520 security/tomoyo/file.c:723
 tomoyo_file_ioctl+0x23/0x30 security/tomoyo/tomoyo.c:335
 security_file_ioctl+0x77/0xc0 security/security.c:1441
 ksys_ioctl+0x56/0x180 fs/ioctl.c:757
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:770
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88805005c000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 2888 bytes inside of
 4096-byte region [ffff88805005c000, ffff88805005d000)
The buggy address belongs to the page:
page:ffffea0001401700 refcount:1 mapcount:0 mapping:ffff8880aa402000 index:0x0 compound_mapcount: 0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea0001401488 ffffea0001401a08 ffff8880aa402000
raw: 0000000000000000 ffff88805005c000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88805005ca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805005ca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805005cb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff88805005cb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805005cc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/02/14 01:28 upstream 0bf999f9c5e7 c5ed587f .config console log report ci-upstream-kasan-gce
* Struck through repros no longer work on HEAD.