================================================================== BUG: KASAN: use-after-free in erspan_build_header+0x3bf/0x3d0 net/ipv4/ip_gre.c:698 Read of size 2 at addr ffff8801cd8b60cb by task syz-executor6/5028 audit: type=1400 audit(1516970246.187:26): avc: denied { set_context_mgr } for pid=5020 comm="syz-executor7" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=binder permissive=1 CPU: 0 PID: 5028 Comm: syz-executor6 Not tainted 4.15.0-rc9+ #281 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_error mm/kasan/report.c:351 [inline] kasan_report+0x25b/0x340 mm/kasan/report.c:409 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:440 audit: type=1400 audit(1516970246.187:27): avc: denied { map_create } for pid=5026 comm="syz-executor3" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=bpf permissive=1 audit: type=1400 audit(1516970246.187:28): avc: denied { map_read map_write } for pid=5026 comm="syz-executor3" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=bpf permissive=1 erspan_build_header+0x3bf/0x3d0 net/ipv4/ip_gre.c:698 erspan_xmit+0x3b8/0x13b0 net/ipv4/ip_gre.c:740 __netdev_start_xmit include/linux/netdevice.h:4042 [inline] netdev_start_xmit include/linux/netdevice.h:4051 [inline] packet_direct_xmit+0x315/0x6b0 net/packet/af_packet.c:266 packet_snd net/packet/af_packet.c:2943 [inline] packet_sendmsg+0x3aed/0x60b0 net/packet/af_packet.c:2968 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg+0xca/0x110 net/socket.c:648 SYSC_sendto+0x361/0x5c0 net/socket.c:1729 SyS_sendto+0x40/0x50 net/socket.c:1697 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x452f19 RSP: 002b:00007fc15ea37c58 EFLAGS: 00000212 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452f19 RDX: 0000000000000000 RSI: 0000000020015f41 RDI: 0000000000000013 RBP: 00000000000005df R08: 0000000020015fec R09: 0000000000000014 R10: ffffffffffffffff R11: 0000000000000212 R12: 00000000006f7d88 R13: 00000000ffffffff R14: 00007fc15ea386d4 R15: 0000000000000000 Allocated by task 3649: 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.39+0x41/0xd0 net/core/skbuff.c:137 __alloc_skb+0x13b/0x780 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:983 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1147 [inline] netlink_sendmsg+0xa86/0xe60 net/netlink/af_netlink.c:1839 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg+0xca/0x110 net/socket.c:648 SYSC_sendto+0x361/0x5c0 net/socket.c:1729 SyS_sendto+0x40/0x50 net/socket.c:1697 entry_SYSCALL_64_fastpath+0x29/0xa0 Freed by task 3649: 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 netlink_dump+0xa36/0xcf0 net/netlink/af_netlink.c:2225 netlink_recvmsg+0x9bf/0x1300 net/netlink/af_netlink.c:1947 sock_recvmsg_nosec net/socket.c:811 [inline] sock_recvmsg+0xc9/0x110 net/socket.c:818 ___sys_recvmsg+0x2a4/0x640 net/socket.c:2187 __sys_recvmsg+0xe2/0x210 net/socket.c:2232 SYSC_recvmsg net/socket.c:2244 [inline] SyS_recvmsg+0x2d/0x50 net/socket.c:2239 entry_SYSCALL_64_fastpath+0x29/0xa0 The buggy address belongs to the object at ffff8801cd8b60c0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 11 bytes inside of 512-byte region [ffff8801cd8b60c0, ffff8801cd8b62c0) The buggy address belongs to the page: page:ffffea0007362d80 count:1 mapcount:0 mapping:ffff8801cd8b60c0 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801cd8b60c0 0000000000000000 0000000100000006 raw: ffffea0007122d60 ffffea0007120c20 ffff8801dac00940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801cd8b5f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801cd8b6000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801cd8b6080: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8801cd8b6100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801cd8b6180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================