KASAN: slab-out-of-bounds Read in fib6_purge

Title	Replies (including bot)	Last reply
Reminder: 99 open syzbot bugs in net subsystem	14 (14)	2019/07/31 15:13
Reminder: 94 open syzbot bugs in net subsystem	1 (1)	2019/06/25 05:48
KASAN: slab-out-of-bounds Read in fib6_purge_rt (2)	0 (1)	2019/06/04 05:07

================================================================== BUG: KASAN: slab-out-of-bounds in __read_once_size include/linux/compiler.h:194 [inline] BUG: KASAN: slab-out-of-bounds in __fib6_drop_pcpu_from net/ipv6/ip6_fib.c:899 [inline] BUG: KASAN: slab-out-of-bounds in fib6_drop_pcpu_from net/ipv6/ip6_fib.c:920 [inline] BUG: KASAN: slab-out-of-bounds in fib6_purge_rt+0x5bf/0x630 net/ipv6/ip6_fib.c:928 Read of size 8 at addr ffff88809906c2b6 by task kworker/u4:6/8858 CPU: 1 PID: 8858 Comm: kworker/u4:6 Not tainted 5.2.0-rc2+ #13 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 kasan_report+0x12/0x20 mm/kasan/common.c:614 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 __read_once_size include/linux/compiler.h:194 [inline] __fib6_drop_pcpu_from net/ipv6/ip6_fib.c:899 [inline] fib6_drop_pcpu_from net/ipv6/ip6_fib.c:920 [inline] fib6_purge_rt+0x5bf/0x630 net/ipv6/ip6_fib.c:928 fib6_del_route net/ipv6/ip6_fib.c:1811 [inline] fib6_del+0x9bd/0xeb0 net/ipv6/ip6_fib.c:1842 fib6_clean_node+0x3a5/0x590 net/ipv6/ip6_fib.c:2004 fib6_walk_continue+0x4a9/0x8e0 net/ipv6/ip6_fib.c:1926 fib6_walk+0x9d/0x100 net/ipv6/ip6_fib.c:1974 fib6_clean_tree+0xe0/0x120 net/ipv6/ip6_fib.c:2053 __fib6_clean_all+0x118/0x2a0 net/ipv6/ip6_fib.c:2069 fib6_clean_all+0x2b/0x40 net/ipv6/ip6_fib.c:2080 rt6_sync_down_dev+0x134/0x150 net/ipv6/route.c:4285 rt6_disable_ip+0x27/0x5f0 net/ipv6/route.c:4290 addrconf_ifdown+0xa2/0x1220 net/ipv6/addrconf.c:3707 addrconf_notify+0x5db/0x2370 net/ipv6/addrconf.c:3632 notifier_call_chain+0xc2/0x230 kernel/notifier.c:95 __raw_notifier_call_chain kernel/notifier.c:396 [inline] raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:403 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1753 call_netdevice_notifiers_extack net/core/dev.c:1765 [inline] call_netdevice_notifiers net/core/dev.c:1779 [inline] dev_close_many+0x33f/0x6f0 net/core/dev.c:1522 rollback_registered_many+0x43b/0xfc0 net/core/dev.c:8159 unregister_netdevice_many.part.0+0x1b/0x1f0 net/core/dev.c:9290 unregister_netdevice_many+0x3b/0x50 net/core/dev.c:9289 sit_exit_batch_net+0x560/0x750 net/ipv6/sit.c:1895 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:157 cleanup_net+0x3fb/0x960 net/core/net_namespace.c:553 process_one_work+0x989/0x1790 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x354/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Allocated by task 11059: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_kmalloc mm/kasan/common.c:489 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:497 slab_post_alloc_hook mm/slab.h:437 [inline] slab_alloc mm/slab.c:3326 [inline] kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3488 dst_alloc+0x10e/0x200 net/core/dst.c:93 ip6_dst_alloc+0x34/0xa0 net/ipv6/route.c:356 ip6_rt_pcpu_alloc net/ipv6/route.c:1257 [inline] rt6_make_pcpu_route net/ipv6/route.c:1287 [inline] ip6_pol_route+0x649/0x1010 net/ipv6/route.c:2031 ip6_pol_route_output+0x54/0x70 net/ipv6/route.c:2204 fib6_rule_lookup+0x133/0x5a0 net/ipv6/fib6_rules.c:116 ip6_route_output_flags+0x2c4/0x350 net/ipv6/route.c:2233 ip6_route_output include/net/ip6_route.h:89 [inline] ip6_dst_lookup_tail+0xd10/0x1b30 net/ipv6/ip6_output.c:1027 ip6_dst_lookup_flow+0xa8/0x220 net/ipv6/ip6_output.c:1155 sctp_v6_get_dst+0x785/0x1d80 net/sctp/ipv6.c:278 sctp_transport_route+0x12d/0x360 net/sctp/transport.c:297 sctp_assoc_add_peer+0x53e/0xfc0 net/sctp/associola.c:663 sctp_process_param net/sctp/sm_make_chunk.c:2531 [inline] sctp_process_init+0x2491/0x2b10 net/sctp/sm_make_chunk.c:2344 sctp_sf_do_5_1D_ce+0x458/0x1390 net/sctp/sm_statefuns.c:767 sctp_do_sm+0x121/0x50e0 net/sctp/sm_sideeffect.c:1147 sctp_endpoint_bh_rcv+0x451/0x950 net/sctp/endpointola.c:443 sctp_inq_push+0x1e4/0x280 net/sctp/inqueue.c:80 sctp_rcv+0x2807/0x35c0 net/sctp/input.c:256 sctp6_rcv+0x17/0x30 net/sctp/ipv6.c:1049 ip6_protocol_deliver_rcu+0x2fe/0x16c0 net/ipv6/ip6_input.c:401 ip6_input_finish+0x84/0x170 net/ipv6/ip6_input.c:442 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip6_input+0xe4/0x3f0 net/ipv6/ip6_input.c:451 dst_input include/net/dst.h:439 [inline] ip6_rcv_finish+0x1de/0x310 net/ipv6/ip6_input.c:80 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:276 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:4985 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5099 process_backlog+0x206/0x750 net/core/dev.c:5910 napi_poll net/core/dev.c:6333 [inline] net_rx_action+0x4f5/0x1070 net/core/dev.c:6399 __do_softirq+0x25c/0x94c kernel/softirq.c:293 Freed by task 10228: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459 __cache_free mm/slab.c:3432 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3698 dst_destroy+0x29e/0x3c0 net/core/dst.c:129 dst_destroy_rcu+0x16/0x19 net/core/dst.c:142 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2092 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline] rcu_core+0xba5/0x1500 kernel/rcu/tree.c:2291 __do_softirq+0x25c/0x94c kernel/softirq.c:293 The buggy address belongs to the object at ffff88809906c1c0 which belongs to the cache ip6_dst_cache of size 224 The buggy address is located 22 bytes to the right of 224-byte region [ffff88809906c1c0, ffff88809906c2a0) The buggy address belongs to the page: page:ffffea0002641b00 refcount:1 mapcount:0 mapping:ffff8882164c0680 index:0xffff88809906cbc0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea00025c0748 ffffea0002595a08 ffff8882164c0680 raw: ffff88809906cbc0 ffff88809906c080 000000010000000b 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809906c180: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ffff88809906c200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88809906c280: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88809906c300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88809906c380: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc ==================================================================