================================================================== BUG: KASAN: use-after-free in ____bpf_skb_change_tail net/core/filter.c:2371 [inline] BUG: KASAN: use-after-free in bpf_skb_change_tail+0xa7f/0xba0 net/core/filter.c:2368 Read of size 8 at addr ffff888092d2db50 by task syz-executor.3/15061 CPU: 0 PID: 15061 Comm: syz-executor.3 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_load8_noabort+0x14/0x20 mm/kasan/report.c:430 ____bpf_skb_change_tail net/core/filter.c:2371 [inline] bpf_skb_change_tail+0xa7f/0xba0 net/core/filter.c:2368 bpf_prog_ac477e10ee530e9d+0x963/0x1000 Allocated by task 14933: 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] dccp_send_ack+0xc7/0x330 net/dccp/output.c:580 ccid2_hc_rx_packet_recv+0x10e/0x180 net/dccp/ccids/ccid2.c:778 ccid_hc_rx_packet_recv net/dccp/ccid.h:185 [inline] dccp_deliver_input_to_ccids+0xdd/0x250 net/dccp/input.c:180 dccp_rcv_established net/dccp/input.c:378 [inline] dccp_rcv_established+0x6b/0xb0 net/dccp/input.c:368 dccp_v4_do_rcv+0x122/0x170 net/dccp/ipv4.c:656 sk_backlog_rcv include/net/sock.h:912 [inline] __sk_receive_skb+0x226/0x950 net/core/sock.c:511 dccp_v4_rcv+0xd47/0x1903 net/dccp/ipv4.c:877 ip_local_deliver_finish+0x25e/0xad0 net/ipv4/ip_input.c:216 NF_HOOK include/linux/netfilter.h:250 [inline] NF_HOOK include/linux/netfilter.h:244 [inline] ip_local_deliver+0x1c3/0x4a0 net/ipv4/ip_input.c:257 dst_input include/net/dst.h:468 [inline] ip_rcv_finish+0x7be/0x1a50 net/ipv4/ip_input.c:396 NF_HOOK include/linux/netfilter.h:250 [inline] NF_HOOK include/linux/netfilter.h:244 [inline] ip_rcv+0xaa5/0x112b net/ipv4/ip_input.c:493 __netif_receive_skb_core+0x1eae/0x2ca0 net/core/dev.c:4477 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4515 process_backlog+0x21f/0x730 net/core/dev.c:5197 napi_poll net/core/dev.c:5598 [inline] net_rx_action+0x490/0xf80 net/core/dev.c:5664 __do_softirq+0x244/0x9a0 kernel/softirq.c:288 Freed by task 14933: 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+0x1e/0x30 net/core/skbuff.c:646 __dccp_rcv_established.isra.0+0x178/0x340 net/dccp/input.c:364 dccp_rcv_established net/dccp/input.c:380 [inline] dccp_rcv_established+0x76/0xb0 net/dccp/input.c:368 dccp_v4_do_rcv+0x122/0x170 net/dccp/ipv4.c:656 sk_backlog_rcv include/net/sock.h:912 [inline] __release_sock+0x12d/0x350 net/core/sock.c:2259 release_sock+0x59/0x1b0 net/core/sock.c:2774 dccp_sendmsg+0x57e/0x950 net/dccp/proto.c:813 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 ffff888092d2dac0 which belongs to the cache skbuff_head_cache of size 232 The buggy address is located 144 bytes inside of 232-byte region [ffff888092d2dac0, ffff888092d2dba8) The buggy address belongs to the page: page:ffffea00024b4b40 count:1 mapcount:0 mapping:ffff888092d2d0c0 index:0xffff888092d2d980 flags: 0x1fffc0000000100(slab) raw: 01fffc0000000100 ffff888092d2d0c0 ffff888092d2d980 0000000100000008 raw: ffffea000245d460 ffffea0002643ee0 ffff88821b75f240 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888092d2da00: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc ffff888092d2da80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff888092d2db00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888092d2db80: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc ffff888092d2dc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================