syzbot


KASAN: double-free or invalid-free in skb_free_head

Status: fixed on 2018/02/01 16:29
Subsystems: net virt
[Documentation on labels]
Reported-by: syzbot+f62f0e8fec2f608fcdf31644e40f2b5ac4a362fe@syzkaller.appspotmail.com
Fix commit: d76c68109f37 crypto: pcrypt - fix freeing pcrypt instances
First crash: 2355d, last: 2344d

Sample crash report:
==================================================================
BUG: KASAN: double-free or invalid-free in skb_free_head+0x74/0xb0 net/core/skbuff.c:550

CPU: 1 PID: 3151 Comm: sshd Not tainted 4.15.0-rc4+ #235
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_double_free+0x55/0x80 mm/kasan/report.c:333
 kasan_slab_free+0xa3/0xc0 mm/kasan/kasan.c:514
 __cache_free mm/slab.c:3488 [inline]
 kfree+0xd6/0x260 mm/slab.c:3803
 skb_free_head+0x74/0xb0 net/core/skbuff.c:550
 skb_release_data+0x58c/0x790 net/core/skbuff.c:570
 skb_release_all+0x4a/0x60 net/core/skbuff.c:627
 __kfree_skb net/core/skbuff.c:641 [inline]
 consume_skb+0x153/0x490 net/core/skbuff.c:701
 __dev_kfree_skb_any+0x85/0xa0 net/core/dev.c:2515
 dev_consume_skb_any include/linux/netdevice.h:3276 [inline]
 free_old_xmit_skbs.isra.27+0x15a/0x2c0 drivers/net/virtio_net.c:1167
 start_xmit+0x1b9/0x1650 drivers/net/virtio_net.c:1314
 __netdev_start_xmit include/linux/netdevice.h:4042 [inline]
 netdev_start_xmit include/linux/netdevice.h:4051 [inline]
 xmit_one net/core/dev.c:2991 [inline]
 dev_hard_start_xmit+0x248/0xac0 net/core/dev.c:3007
 sch_direct_xmit+0x31d/0x6d0 net/sched/sch_generic.c:187
 __dev_xmit_skb net/core/dev.c:3189 [inline]
 __dev_queue_xmit+0x16f4/0x2070 net/core/dev.c:3456
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3521
 neigh_hh_output include/net/neighbour.h:472 [inline]
 neigh_output include/net/neighbour.h:480 [inline]
 ip_finish_output2+0xece/0x1460 net/ipv4/ip_output.c:229
 ip_finish_output+0x85e/0xd10 net/ipv4/ip_output.c:317
 NF_HOOK_COND include/linux/netfilter.h:239 [inline]
 ip_output+0x1cc/0x860 net/ipv4/ip_output.c:405
 dst_output include/net/dst.h:460 [inline]
 ip_local_out+0x95/0x160 net/ipv4/ip_output.c:124
 ip_queue_xmit+0x8c6/0x18e0 net/ipv4/ip_output.c:504
 tcp_transmit_skb+0x1b12/0x38b0 net/ipv4/tcp_output.c:1176
 tcp_write_xmit+0x680/0x5190 net/ipv4/tcp_output.c:2367
 __tcp_push_pending_frames+0xa0/0x250 net/ipv4/tcp_output.c:2543
 tcp_push+0x538/0x770 net/ipv4/tcp.c:730
 tcp_sendmsg_locked+0x2663/0x3b30 net/ipv4/tcp.c:1424
 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1461
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
 sock_sendmsg_nosec net/socket.c:636 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:646
 sock_write_iter+0x31a/0x5d0 net/socket.c:915
 call_write_iter include/linux/fs.h:1772 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x684/0x970 fs/read_write.c:482
 vfs_write+0x189/0x510 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:581
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x7fb44223a370
RSP: 002b:00007fff017fd6e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb44223a370
RDX: 0000000000000038 RSI: 0000557d0b4fe450 RDI: 0000000000000003
RBP: 0000557d0ade6c88 R08: 0000000000000001 R09: 0101010101010101
R10: 0000000000000008 R11: 0000000000000246 R12: 0000557d0b4fc930
R13: 0000557d0ade4fb4 R14: 0000000000000028 R15: 0000557d0ade6ca0

Allocated by task 3151:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 __do_kmalloc_node mm/slab.c:3672 [inline]
 __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3686
 __kmalloc_reserve.isra.41+0x41/0xd0 net/core/skbuff.c:137
 __alloc_skb+0x13b/0x780 net/core/skbuff.c:205
 alloc_skb_fclone include/linux/skbuff.h:1025 [inline]
 sk_stream_alloc_skb+0x11d/0x900 net/ipv4/tcp.c:870
 tcp_sendmsg_locked+0x1341/0x3b30 net/ipv4/tcp.c:1299
 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1461
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
 sock_sendmsg_nosec net/socket.c:636 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:646
 sock_write_iter+0x31a/0x5d0 net/socket.c:915
 call_write_iter include/linux/fs.h:1772 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x684/0x970 fs/read_write.c:482
 vfs_write+0x189/0x510 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:581
 entry_SYSCALL_64_fastpath+0x1f/0x96

Freed by task 3151:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3488 [inline]
 kfree+0xd6/0x260 mm/slab.c:3803
 skb_free_head+0x74/0xb0 net/core/skbuff.c:550
 skb_release_data+0x58c/0x790 net/core/skbuff.c:570
 skb_release_all+0x4a/0x60 net/core/skbuff.c:627
 __kfree_skb net/core/skbuff.c:641 [inline]
 consume_skb+0x153/0x490 net/core/skbuff.c:701
 __dev_kfree_skb_any+0x85/0xa0 net/core/dev.c:2515
 dev_consume_skb_any include/linux/netdevice.h:3276 [inline]
 free_old_xmit_skbs.isra.27+0x15a/0x2c0 drivers/net/virtio_net.c:1167
 start_xmit+0x1b9/0x1650 drivers/net/virtio_net.c:1314
 __netdev_start_xmit include/linux/netdevice.h:4042 [inline]
 netdev_start_xmit include/linux/netdevice.h:4051 [inline]
 xmit_one net/core/dev.c:2991 [inline]
 dev_hard_start_xmit+0x248/0xac0 net/core/dev.c:3007
 sch_direct_xmit+0x31d/0x6d0 net/sched/sch_generic.c:187
 __dev_xmit_skb net/core/dev.c:3189 [inline]
 __dev_queue_xmit+0x16f4/0x2070 net/core/dev.c:3456
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3521
 neigh_hh_output include/net/neighbour.h:472 [inline]
 neigh_output include/net/neighbour.h:480 [inline]
 ip_finish_output2+0xece/0x1460 net/ipv4/ip_output.c:229
 ip_finish_output+0x85e/0xd10 net/ipv4/ip_output.c:317
 NF_HOOK_COND include/linux/netfilter.h:239 [inline]
 ip_output+0x1cc/0x860 net/ipv4/ip_output.c:405
 dst_output include/net/dst.h:460 [inline]
 ip_local_out+0x95/0x160 net/ipv4/ip_output.c:124
 ip_queue_xmit+0x8c6/0x18e0 net/ipv4/ip_output.c:504
 tcp_transmit_skb+0x1b12/0x38b0 net/ipv4/tcp_output.c:1176
 tcp_write_xmit+0x680/0x5190 net/ipv4/tcp_output.c:2367
 __tcp_push_pending_frames+0xa0/0x250 net/ipv4/tcp_output.c:2543
 tcp_push+0x538/0x770 net/ipv4/tcp.c:730
 tcp_sendmsg_locked+0x2663/0x3b30 net/ipv4/tcp.c:1424
 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1461
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
 sock_sendmsg_nosec net/socket.c:636 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:646
 sock_write_iter+0x31a/0x5d0 net/socket.c:915
 call_write_iter include/linux/fs.h:1772 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x684/0x970 fs/read_write.c:482
 vfs_write+0x189/0x510 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:581
 entry_SYSCALL_64_fastpath+0x1f/0x96

The buggy address belongs to the object at ffff8801c79336c0
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 0 bytes inside of
 1024-byte region [ffff8801c79336c0, ffff8801c7933ac0)
The buggy address belongs to the page:
page:0000000063bdf4fd count:1 mapcount:0 mapping:000000006ae07d95 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801c7932040 0000000000000000 0000000100000007
raw: ffffea00071fc7a0 ffffea00071fdea0 ffff8801db000ac0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c7933580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801c7933600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801c7933680: fb fb fb fb fb fb fb fb fb fb fb fb 00 00 00 00
                                           ^
 ffff8801c7933700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c7933780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2017/12/23 13:20 upstream 9c294ec08408 73aba437 .config console log report syz C ci-upstream-kasan-gce
2017/12/20 08:25 upstream 10a7e9d84915 2d836b1d .config console log report syz C ci-upstream-kasan-gce
2017/12/19 07:41 upstream ace52288edf0 1c4160ef .config console log report syz C ci-upstream-kasan-gce
2017/12/19 02:14 upstream 1291a0d5049d 1c4160ef .config console log report syz C ci-upstream-kasan-gce
2017/12/18 19:04 upstream 1291a0d5049d 1c4160ef .config console log report syz C ci-upstream-kasan-gce
2017/12/17 09:26 upstream f3b5ad89de16 b6f0c91b .config console log report syz C ci-upstream-kasan-gce
2017/12/19 07:39 upstream ace52288edf0 1c4160ef .config console log report syz C ci-upstream-kasan-gce-386
2017/12/18 18:58 upstream 1291a0d5049d 1c4160ef .config console log report syz C ci-upstream-kasan-gce-386
2017/12/17 01:47 upstream f3b5ad89de16 b6f0c91b .config console log report syz C ci-upstream-kasan-gce-386
2017/12/13 21:29 upstream d39a01eff9af 06ea774d .config console log report syz C ci-upstream-kasan-gce-386
2017/12/20 04:44 net-next-old f39a5c01c3d2 2d836b1d .config console log report syz C ci-upstream-net-kasan-gce
2017/12/24 13:39 linux-next 0e08c463db38 73aba437 .config console log report syz C ci-upstream-next-kasan-gce
2017/12/17 01:23 mmots 82bcf1def3b5 b6f0c91b .config console log report syz C ci-upstream-mmots-kasan-gce
* Struck through repros no longer work on HEAD.