syzbot


KASAN: use-after-free Read in xfrm_migrate

Status: fixed on 2019/03/06 07:43
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+efd77299e1e802fe8f8f@syzkaller.appspotmail.com
Fix commit: 12750abad517 xfrm: policy: fix infinite loop when merging src-nodes
First crash: 1931d, last: 1909d
Discussions (1)
Title Replies (including bot) Last reply
KASAN: use-after-free Read in xfrm_migrate 0 (1) 2019/01/07 09:53

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in xfrm_migrate_policy_find net/xfrm/xfrm_policy.c:4055 [inline]
BUG: KASAN: use-after-free in xfrm_migrate+0x178f/0x1a30 net/xfrm/xfrm_policy.c:4193
Read of size 4 at addr ffff8880901edbb4 by task syz-executor2/4922

CPU: 0 PID: 4922 Comm: syz-executor2 Not tainted 5.0.0-rc3+ #24
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+0x1db/0x2d0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:134
 xfrm_migrate_policy_find net/xfrm/xfrm_policy.c:4055 [inline]
 xfrm_migrate+0x178f/0x1a30 net/xfrm/xfrm_policy.c:4193
 xfrm_do_migrate+0x9e5/0xd90 net/xfrm/xfrm_user.c:2380
 xfrm_user_rcv_msg+0x458/0x8d0 net/xfrm/xfrm_user.c:2663
 netlink_rcv_skb+0x17d/0x410 net/netlink/af_netlink.c:2485
 xfrm_netlink_rcv+0x70/0x90 net/xfrm/xfrm_user.c:2671
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x574/0x770 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0xa05/0xf90 net/netlink/af_netlink.c:1925
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xdd/0x130 net/socket.c:631
 ___sys_sendmsg+0x7ec/0x910 net/socket.c:2116
 __sys_sendmsg+0x112/0x270 net/socket.c:2154
 __do_sys_sendmsg net/socket.c:2163 [inline]
 __se_sys_sendmsg net/socket.c:2161 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458089
Code: 6d b7 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f8216caec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458089
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8216caf6d4
R13: 00000000004c568f R14: 00000000004d9400 R15: 00000000ffffffff

Allocated by task 25114:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:496 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504
 __do_kmalloc_node mm/slab.c:3673 [inline]
 __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3687
 __kmalloc_reserve.isra.0+0x40/0xe0 net/core/skbuff.c:140
 __alloc_skb+0x12d/0x730 net/core/skbuff.c:208
 alloc_skb include/linux/skbuff.h:1011 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline]
 netlink_sendmsg+0xb11/0xf90 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xdd/0x130 net/socket.c:631
 ___sys_sendmsg+0x7ec/0x910 net/socket.c:2116
 __sys_sendmsg+0x112/0x270 net/socket.c:2154
 __do_sys_sendmsg net/socket.c:2163 [inline]
 __se_sys_sendmsg net/socket.c:2161 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 25114:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466
 __cache_free mm/slab.c:3487 [inline]
 kfree+0xcf/0x230 mm/slab.c:3806
 skb_free_head+0x93/0xb0 net/core/skbuff.c:553
 skb_release_data+0x6ea/0x970 net/core/skbuff.c:573
 skb_release_all+0x4d/0x60 net/core/skbuff.c:627
 __kfree_skb net/core/skbuff.c:641 [inline]
 consume_skb net/core/skbuff.c:701 [inline]
 consume_skb+0x18c/0x550 net/core/skbuff.c:695
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x57c/0x770 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0xa05/0xf90 net/netlink/af_netlink.c:1925
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xdd/0x130 net/socket.c:631
 ___sys_sendmsg+0x7ec/0x910 net/socket.c:2116
 __sys_sendmsg+0x112/0x270 net/socket.c:2154
 __do_sys_sendmsg net/socket.c:2163 [inline]
 __se_sys_sendmsg net/socket.c:2161 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880901edb00
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 180 bytes inside of
 1024-byte region [ffff8880901edb00, ffff8880901edf00)
The buggy address belongs to the page:
page:ffffea0002407b00 count:1 mapcount:0 mapping:ffff88812c3f0ac0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea0001962588 ffffea0002452e88 ffff88812c3f0ac0
raw: 0000000000000000 ffff8880901ec000 0000000100000007 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880901eda80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880901edb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880901edb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff8880901edc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880901edc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/01/30 02:10 net-next-old 085c4c7dd2b6 aa432daf .config console log report ci-upstream-net-kasan-gce
2019/01/25 17:35 net-next-old 556b2710a1ca b5d78bce .config console log report ci-upstream-net-kasan-gce
2019/01/20 13:07 net-next-old 133bbb18ab1a 353f32ea .config console log report ci-upstream-net-kasan-gce
2019/01/20 06:31 net-next-old 133bbb18ab1a 353f32ea .config console log report ci-upstream-net-kasan-gce
2019/01/07 07:28 net-next-old b71acb0e3721 ee332608 .config console log report ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.