================================================================== BUG: KASAN: use-after-free in bpf_skb_proto_xlat net/core/filter.c:2151 [inline] BUG: KASAN: use-after-free in ____bpf_skb_change_proto net/core/filter.c:2189 [inline] BUG: KASAN: use-after-free in bpf_skb_change_proto+0xdbc/0x10f0 net/core/filter.c:2164 Read of size 2 at addr ffff888096109400 by task syz-executor.1/29005 CPU: 0 PID: 29005 Comm: syz-executor.1 Not tainted 4.14.138 #34 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+0x138/0x19c lib/dump_stack.c:53 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:428 bpf_skb_proto_xlat net/core/filter.c:2151 [inline] ____bpf_skb_change_proto net/core/filter.c:2189 [inline] bpf_skb_change_proto+0xdbc/0x10f0 net/core/filter.c:2164 bpf_prog_0a61b7f223ef83f3+0x5f2/0x1000 Allocated by task 27277: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc_node+0x144/0x780 mm/slab.c:3642 __alloc_skb+0x9c/0x500 net/core/skbuff.c:193 alloc_skb include/linux/skbuff.h:980 [inline] alloc_skb_with_frags+0x86/0x4b0 net/core/skbuff.c:5209 sock_alloc_send_pskb+0x5db/0x740 net/core/sock.c:2073 sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2090 __ip_append_data.isra.0+0x1228/0x20c0 net/ipv4/ip_output.c:972 ip_make_skb+0x17a/0x1d0 net/ipv4/ip_output.c:1485 udp_sendmsg+0x16a6/0x1da0 net/ipv4/udp.c:1052 udpv6_sendmsg+0x1312/0x2560 net/ipv6/udp.c:1193 inet_sendmsg+0x122/0x500 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xce/0x110 net/socket.c:656 ___sys_sendmsg+0x349/0x840 net/socket.c:2062 __sys_sendmmsg+0x152/0x3a0 net/socket.c:2152 SYSC_sendmmsg net/socket.c:2183 [inline] SyS_sendmmsg+0x35/0x60 net/socket.c:2178 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 27277: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kmem_cache_free+0x83/0x2b0 mm/slab.c:3758 kfree_skbmem net/core/skbuff.c:586 [inline] kfree_skbmem+0xac/0x120 net/core/skbuff.c:580 __kfree_skb net/core/skbuff.c:646 [inline] kfree_skb+0xbd/0x340 net/core/skbuff.c:663 ip_tunnel_xmit+0x5b7/0x3189 net/ipv4/ip_tunnel.c:805 __gre_xmit+0x4eb/0x890 net/ipv4/ip_gre.c:444 ipgre_xmit+0x3a9/0x710 net/ipv4/ip_gre.c:670 __netdev_start_xmit include/linux/netdevice.h:4033 [inline] netdev_start_xmit include/linux/netdevice.h:4042 [inline] xmit_one net/core/dev.c:3009 [inline] dev_hard_start_xmit+0x18c/0x8b0 net/core/dev.c:3025 __dev_queue_xmit+0x1d95/0x25e0 net/core/dev.c:3525 dev_queue_xmit+0x18/0x20 net/core/dev.c:3558 neigh_connected_output+0x3c5/0x5a0 net/core/neighbour.c:1393 neigh_output include/net/neighbour.h:500 [inline] ip_finish_output2+0x766/0x14a0 net/ipv4/ip_output.c:229 ip_finish_output+0x56d/0xc60 net/ipv4/ip_output.c:317 NF_HOOK_COND include/linux/netfilter.h:239 [inline] ip_mc_output+0x24a/0xd40 net/ipv4/ip_output.c:390 dst_output include/net/dst.h:462 [inline] ip_local_out+0x97/0x170 net/ipv4/ip_output.c:124 ip_send_skb+0x3e/0xc0 net/ipv4/ip_output.c:1418 udp_send_skb+0x616/0xb90 net/ipv4/udp.c:833 udp_sendmsg+0x16df/0x1da0 net/ipv4/udp.c:1057 udpv6_sendmsg+0x1312/0x2560 net/ipv6/udp.c:1193 inet_sendmsg+0x122/0x500 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xce/0x110 net/socket.c:656 ___sys_sendmsg+0x349/0x840 net/socket.c:2062 __sys_sendmmsg+0x152/0x3a0 net/socket.c:2152 SYSC_sendmmsg net/socket.c:2183 [inline] SyS_sendmmsg+0x35/0x60 net/socket.c:2178 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff888096109400 which belongs to the cache skbuff_head_cache of size 232 The buggy address is located 0 bytes inside of 232-byte region [ffff888096109400, ffff8880961094e8) The buggy address belongs to the page: page:ffffea0002584240 count:1 mapcount:0 mapping:ffff888096109040 index:0xffff888096109400 flags: 0x1fffc0000000100(slab) raw: 01fffc0000000100 ffff888096109040 ffff888096109400 000000010000000b raw: ffffea0002a03720 ffffea00022d82e0 ffff88821b757240 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888096109300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888096109380: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc >ffff888096109400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888096109480: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc ffff888096109500: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ==================================================================