On Mon, Apr 10, 2017 at 7:42 PM, Cong Wang <xiyou.wangc...@gmail.com> wrote: > On Mon, Apr 10, 2017 at 7:40 AM, Andrey Konovalov <andreyk...@google.com> > wrote: >> Hi, >> >> I've got the following error report while fuzzing the kernel with syzkaller. >> >> On commit 39da7c509acff13fc8cb12ec1bb20337c988ed36 (4.11-rc6). >> >> Unfortunately it's not reproducible. >> >> BUG: KASAN: use-after-free in ip_select_ttl include/net/dst.h:176 >> [inline] at addr ffff88006ab3602c >> BUG: KASAN: use-after-free in ip_queue_xmit+0x1817/0x1a30 >> net/ipv4/ip_output.c:485 at addr ffff88006ab3602c >> Read of size 4 by task syz-executor1/12627 >> CPU: 3 PID: 12627 Comm: syz-executor1 Not tainted 4.11.0-rc6+ #206 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 >> Call Trace: >> __dump_stack lib/dump_stack.c:16 [inline] >> dump_stack+0x292/0x398 lib/dump_stack.c:52 >> kasan_object_err+0x1c/0x70 mm/kasan/report.c:164 >> print_address_description mm/kasan/report.c:202 [inline] >> kasan_report_error mm/kasan/report.c:291 [inline] >> kasan_report+0x252/0x510 mm/kasan/report.c:347 >> __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:367 >> ip_select_ttl include/net/dst.h:176 [inline] > > Probably same as the one you reported on ipv4_mtu(), it would > be nice if you could test the patch I proposed: > > https://patchwork.ozlabs.org/patch/747556/
Applied your patch. The bug gets triggered very rarely (only twice so far), but I'll let you know if I see it again. Thanks! > > > Thanks! > >> ip_queue_xmit+0x1817/0x1a30 net/ipv4/ip_output.c:485 >> sctp_v4_xmit+0x10d/0x140 net/sctp/protocol.c:994 >> sctp_packet_transmit+0x215c/0x3560 net/sctp/output.c:637 >> sctp_outq_flush+0xade/0x3f90 net/sctp/outqueue.c:885 >> sctp_outq_uncork+0x5a/0x70 net/sctp/outqueue.c:750 >> sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1773 [inline] >> sctp_side_effects net/sctp/sm_sideeffect.c:1175 [inline] >> sctp_do_sm+0x5a0/0x6a50 net/sctp/sm_sideeffect.c:1147 >> sctp_primitive_ASSOCIATE+0x9d/0xd0 net/sctp/primitive.c:88 >> sctp_sendmsg+0x270d/0x3b50 net/sctp/socket.c:1954 >> inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:762 >> sock_sendmsg_nosec net/socket.c:633 [inline] >> sock_sendmsg+0xca/0x110 net/socket.c:643 >> SYSC_sendto+0x660/0x810 net/socket.c:1696 >> SyS_sendto+0x40/0x50 net/socket.c:1664 >> entry_SYSCALL_64_fastpath+0x1f/0xc2 >> RIP: 0033:0x4458d9 >> RSP: 002b:00007fdceca85b58 EFLAGS: 00000282 ORIG_RAX: 000000000000002c >> RAX: ffffffffffffffda RBX: 0000000000000016 RCX: 00000000004458d9 >> RDX: 0000000000000087 RSI: 0000000020003000 RDI: 0000000000000016 >> RBP: 00000000006e2fe0 R08: 0000000020003000 R09: 0000000000000010 >> R10: 0000000000040841 R11: 0000000000000282 R12: 00000000007080a8 >> R13: 000000000000000a R14: 0000000000000005 R15: 0000000000000084 >> Object at ffff88006ab36008, in cache kmalloc-64 size: 64 >> Allocated: >> PID = 7243 >> save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 >> save_stack+0x43/0xd0 mm/kasan/kasan.c:513 >> set_track mm/kasan/kasan.c:525 [inline] >> kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:616 >> kmem_cache_alloc_trace+0x82/0x270 mm/slub.c:2745 >> kmalloc include/linux/slab.h:490 [inline] >> kzalloc include/linux/slab.h:663 [inline] >> fib_create_info+0x8e0/0x3a30 net/ipv4/fib_semantics.c:1040 >> fib_table_insert+0x1a5/0x1550 net/ipv4/fib_trie.c:1221 >> ip_rt_ioctl+0xddc/0x1590 net/ipv4/fib_frontend.c:597 >> inet_ioctl+0xf2/0x1c0 net/ipv4/af_inet.c:882 >> sock_do_ioctl+0x65/0xb0 net/socket.c:906 >> sock_ioctl+0x28f/0x440 net/socket.c:1004 >> vfs_ioctl fs/ioctl.c:45 [inline] >> do_vfs_ioctl+0x1bf/0x1780 fs/ioctl.c:685 >> SYSC_ioctl fs/ioctl.c:700 [inline] >> SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691 >> entry_SYSCALL_64_fastpath+0x1f/0xc2 >> Freed: >> PID = 12622 >> save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 >> save_stack+0x43/0xd0 mm/kasan/kasan.c:513 >> set_track mm/kasan/kasan.c:525 [inline] >> kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:589 >> slab_free_hook mm/slub.c:1357 [inline] >> slab_free_freelist_hook mm/slub.c:1379 [inline] >> slab_free mm/slub.c:2961 [inline] >> kfree+0xe8/0x2b0 mm/slub.c:3882 >> free_fib_info_rcu+0x4ba/0x5e0 net/ipv4/fib_semantics.c:218 >> __rcu_reclaim kernel/rcu/rcu.h:118 [inline] >> rcu_do_batch.isra.64+0x947/0xcc0 kernel/rcu/tree.c:2879 >> invoke_rcu_callbacks kernel/rcu/tree.c:3142 [inline] >> __rcu_process_callbacks kernel/rcu/tree.c:3109 [inline] >> rcu_process_callbacks+0x2cc/0xb90 kernel/rcu/tree.c:3126 >> __do_softirq+0x2fb/0xb7d kernel/softirq.c:284 >> Memory state around the buggy address: >> ffff88006ab35f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >> ffff88006ab35f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >>>ffff88006ab36000: fc fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc >> ^ >> ffff88006ab36080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff88006ab36100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ================================================================== > > -- > You received this message because you are subscribed to the Google Groups > "syzkaller" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to syzkaller+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout.
