On Mon, Feb 13, 2017 at 11:19 AM, Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > Hi, > > I've got the following error report while fuzzing the kernel with syzkaller. > > On commit 926af6273fc683cd98cd0ce7bf0d04a02eed6742. > > A reproducer and .config are attached. > Note, that it takes quite some time to trigger the bug (up to 10 minutes). > > BUG: KASAN: use-after-free in dccp_feat_activate_values+0x967/0xab0 > net/dccp/feat.c:1541 at addr ffff88003713be68 > Read of size 8 by task syz-executor2/8457 > CPU: 2 PID: 8457 Comm: syz-executor2 Not tainted 4.10.0-rc7+ #127 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > Call Trace: > <IRQ> > __dump_stack lib/dump_stack.c:15 [inline] > dump_stack+0x292/0x398 lib/dump_stack.c:51 > kasan_object_err+0x1c/0x70 mm/kasan/report.c:162 > print_address_description mm/kasan/report.c:200 [inline] > kasan_report_error mm/kasan/report.c:289 [inline] > kasan_report.part.1+0x20e/0x4e0 mm/kasan/report.c:311 > kasan_report mm/kasan/report.c:332 [inline] > __asan_report_load8_noabort+0x29/0x30 mm/kasan/report.c:332 > dccp_feat_activate_values+0x967/0xab0 net/dccp/feat.c:1541 > dccp_create_openreq_child+0x464/0x610 net/dccp/minisocks.c:121 > dccp_v6_request_recv_sock+0x1f6/0x1960 net/dccp/ipv6.c:457 > dccp_check_req+0x335/0x5a0 net/dccp/minisocks.c:186 > dccp_v6_rcv+0x69e/0x1d00 net/dccp/ipv6.c:711 > ip6_input_finish+0x46d/0x17a0 net/ipv6/ip6_input.c:279 > NF_HOOK include/linux/netfilter.h:257 [inline] > ip6_input+0xdb/0x590 net/ipv6/ip6_input.c:322 > dst_input include/net/dst.h:507 [inline] > ip6_rcv_finish+0x289/0x890 net/ipv6/ip6_input.c:69 > NF_HOOK include/linux/netfilter.h:257 [inline] > ipv6_rcv+0x12ec/0x23d0 net/ipv6/ip6_input.c:203 > __netif_receive_skb_core+0x1ae5/0x3400 net/core/dev.c:4190 > __netif_receive_skb+0x2a/0x170 net/core/dev.c:4228 > process_backlog+0xe5/0x6c0 net/core/dev.c:4839 > napi_poll net/core/dev.c:5202 [inline] > net_rx_action+0xe70/0x1900 net/core/dev.c:5267 > __do_softirq+0x2fb/0xb7d kernel/softirq.c:284 > do_softirq_own_stack+0x1c/0x30 arch/x86/entry/entry_64.S:902 Seems there is a race condition between iterating dccp_feat_entry and freeing it, bh_lock_sock() seems not held in this path. > </IRQ> > do_softirq.part.17+0x1e8/0x230 kernel/softirq.c:328 > do_softirq kernel/softirq.c:176 [inline] > __local_bh_enable_ip+0x1f2/0x200 kernel/softirq.c:181 > local_bh_enable include/linux/bottom_half.h:31 [inline] > rcu_read_unlock_bh include/linux/rcupdate.h:971 [inline] > ip6_finish_output2+0xbb0/0x23d0 net/ipv6/ip6_output.c:123 > ip6_finish_output+0x302/0x960 net/ipv6/ip6_output.c:148 > NF_HOOK_COND include/linux/netfilter.h:246 [inline] > ip6_output+0x1cb/0x8d0 net/ipv6/ip6_output.c:162 > ip6_xmit+0xcdf/0x20d0 include/net/dst.h:501 > inet6_csk_xmit+0x320/0x5f0 net/ipv6/inet6_connection_sock.c:179 > dccp_transmit_skb+0xb09/0x1120 net/dccp/output.c:141 > dccp_xmit_packet+0x215/0x760 net/dccp/output.c:280 > dccp_write_xmit+0x168/0x1d0 net/dccp/output.c:362 > dccp_sendmsg+0x79c/0xb10 net/dccp/proto.c:796 > inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744 > sock_sendmsg_nosec net/socket.c:635 [inline] > sock_sendmsg+0xca/0x110 net/socket.c:645 > SYSC_sendto+0x660/0x810 net/socket.c:1687 > SyS_sendto+0x40/0x50 net/socket.c:1655 > entry_SYSCALL_64_fastpath+0x1f/0xc2 > RIP: 0033:0x4458b9 > RSP: 002b:00007f8ceb77bb58 EFLAGS: 00000282 ORIG_RAX: 000000000000002c > RAX: ffffffffffffffda RBX: 0000000000000017 RCX: 00000000004458b9 > RDX: 0000000000000023 RSI: 0000000020e60000 RDI: 0000000000000017 > RBP: 00000000006e1b90 R08: 00000000200f9fe1 R09: 0000000000000020 > R10: 0000000000008010 R11: 0000000000000282 R12: 00000000007080a8 > R13: 0000000000000000 R14: 00007f8ceb77c9c0 R15: 00007f8ceb77c700 > Object at ffff88003713be50, in cache kmalloc-64 size: 64 > Allocated: > PID = 8446 > save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 > save_stack+0x43/0xd0 mm/kasan/kasan.c:502 > set_track mm/kasan/kasan.c:514 [inline] > kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:605 > kmem_cache_alloc_trace+0x82/0x270 mm/slub.c:2738 > kmalloc include/linux/slab.h:490 [inline] > dccp_feat_entry_new+0x214/0x410 net/dccp/feat.c:467 > dccp_feat_push_change+0x38/0x220 net/dccp/feat.c:487 > __feat_register_sp+0x223/0x2f0 net/dccp/feat.c:741 > dccp_feat_propagate_ccid+0x22b/0x2b0 net/dccp/feat.c:949 > dccp_feat_server_ccid_dependencies+0x1b3/0x250 net/dccp/feat.c:1012 > dccp_make_response+0x1f1/0xc90 net/dccp/output.c:423 > dccp_v6_send_response+0x4ec/0xc20 net/dccp/ipv6.c:217 > dccp_v6_conn_request+0xaba/0x11b0 net/dccp/ipv6.c:377 > dccp_rcv_state_process+0x51e/0x1650 net/dccp/input.c:606 > dccp_v6_do_rcv+0x213/0x350 net/dccp/ipv6.c:632 > sk_backlog_rcv include/net/sock.h:893 [inline] > __sk_receive_skb+0x36f/0xcc0 net/core/sock.c:479 > dccp_v6_rcv+0xba5/0x1d00 net/dccp/ipv6.c:742 > ip6_input_finish+0x46d/0x17a0 net/ipv6/ip6_input.c:279 > NF_HOOK include/linux/netfilter.h:257 [inline] > ip6_input+0xdb/0x590 net/ipv6/ip6_input.c:322 > dst_input include/net/dst.h:507 [inline] > ip6_rcv_finish+0x289/0x890 net/ipv6/ip6_input.c:69 > NF_HOOK include/linux/netfilter.h:257 [inline] > ipv6_rcv+0x12ec/0x23d0 net/ipv6/ip6_input.c:203 > __netif_receive_skb_core+0x1ae5/0x3400 net/core/dev.c:4190 > __netif_receive_skb+0x2a/0x170 net/core/dev.c:4228 > process_backlog+0xe5/0x6c0 net/core/dev.c:4839 > napi_poll net/core/dev.c:5202 [inline] > net_rx_action+0xe70/0x1900 net/core/dev.c:5267 > __do_softirq+0x2fb/0xb7d kernel/softirq.c:284 > Freed: > PID = 15 > save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 > save_stack+0x43/0xd0 mm/kasan/kasan.c:502 > set_track mm/kasan/kasan.c:514 [inline] > kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:578 > slab_free_hook mm/slub.c:1355 [inline] > slab_free_freelist_hook mm/slub.c:1377 [inline] > slab_free mm/slub.c:2954 [inline] > kfree+0xe8/0x2b0 mm/slub.c:3874 > dccp_feat_entry_destructor.part.4+0x48/0x60 net/dccp/feat.c:418 > dccp_feat_entry_destructor net/dccp/feat.c:416 [inline] > dccp_feat_list_pop net/dccp/feat.c:541 [inline] > dccp_feat_activate_values+0x57f/0xab0 net/dccp/feat.c:1543 > dccp_create_openreq_child+0x464/0x610 net/dccp/minisocks.c:121 > dccp_v6_request_recv_sock+0x1f6/0x1960 net/dccp/ipv6.c:457 > dccp_check_req+0x335/0x5a0 net/dccp/minisocks.c:186 > dccp_v6_rcv+0x69e/0x1d00 net/dccp/ipv6.c:711 > ip6_input_finish+0x46d/0x17a0 net/ipv6/ip6_input.c:279 > NF_HOOK include/linux/netfilter.h:257 [inline] > ip6_input+0xdb/0x590 net/ipv6/ip6_input.c:322 > dst_input include/net/dst.h:507 [inline] > ip6_rcv_finish+0x289/0x890 net/ipv6/ip6_input.c:69 > NF_HOOK include/linux/netfilter.h:257 [inline] > ipv6_rcv+0x12ec/0x23d0 net/ipv6/ip6_input.c:203 > __netif_receive_skb_core+0x1ae5/0x3400 net/core/dev.c:4190 > __netif_receive_skb+0x2a/0x170 net/core/dev.c:4228 > process_backlog+0xe5/0x6c0 net/core/dev.c:4839 > napi_poll net/core/dev.c:5202 [inline] > net_rx_action+0xe70/0x1900 net/core/dev.c:5267 > __do_softirq+0x2fb/0xb7d kernel/softirq.c:284 > Memory state around the buggy address: > ffff88003713bd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff88003713bd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>ffff88003713be00: fc fc fc fc fc fc fc fc fc fc fb fb fb fb fb fb > ^ > ffff88003713be80: fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff88003713bf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ================================================================== > Disabling lock debugging due to kernel taint > Kernel panic - not syncing: panic_on_warn set ... -- To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
