================================================================== BUG: KASAN: use-after-free in decode_session6+0xe7c/0x1580 net/xfrm/xfrm_policy.c:3393 Read of size 1 at addr ffff88802b0d88af by task syz-executor.5/21563 CPU: 0 PID: 21563 Comm: syz-executor.5 Not tainted 5.10.0-rc2-next-20201104-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x4c8 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562 decode_session6+0xe7c/0x1580 net/xfrm/xfrm_policy.c:3393 __xfrm_decode_session net/xfrm/xfrm_policy.c:3485 [inline] __xfrm_policy_check+0x2fa/0x2850 net/xfrm/xfrm_policy.c:3540 __xfrm_policy_check2 include/net/xfrm.h:1097 [inline] xfrm_policy_check include/net/xfrm.h:1106 [inline] sctp_rcv+0x12b0/0x2e30 net/sctp/input.c:202 sctp6_rcv+0x22/0x40 net/sctp/ipv6.c:1078 ip6_protocol_deliver_rcu+0x2e8/0x1680 net/ipv6/ip6_input.c:433 ip6_input_finish+0x7f/0x160 net/ipv6/ip6_input.c:474 NF_HOOK include/linux/netfilter.h:301 [inline] NF_HOOK include/linux/netfilter.h:295 [inline] ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:483 dst_input include/net/dst.h:447 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] NF_HOOK include/linux/netfilter.h:295 [inline] ipv6_rcv+0x28e/0x3c0 net/ipv6/ip6_input.c:307 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5315 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5429 process_backlog+0x232/0x6c0 net/core/dev.c:6319 napi_poll net/core/dev.c:6763 [inline] net_rx_action+0x4dc/0x1100 net/core/dev.c:6833 __do_softirq+0x2a0/0x9f6 kernel/softirq.c:298 asm_call_irq_on_stack+0xf/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0xaa/0xd0 arch/x86/kernel/irq_64.c:77 do_softirq kernel/softirq.c:343 [inline] do_softirq+0xb5/0xe0 kernel/softirq.c:330 __local_bh_enable_ip+0xf0/0x110 kernel/softirq.c:195 local_bh_enable include/linux/bottom_half.h:32 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:731 [inline] ip6_finish_output2+0x71f/0x16c0 net/ipv6/ip6_output.c:118 __ip6_finish_output net/ipv6/ip6_output.c:143 [inline] __ip6_finish_output+0x447/0xab0 net/ipv6/ip6_output.c:128 ip6_finish_output+0x34/0x1f0 net/ipv6/ip6_output.c:153 NF_HOOK_COND include/linux/netfilter.h:290 [inline] ip6_output+0x1db/0x520 net/ipv6/ip6_output.c:176 dst_output include/net/dst.h:441 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] NF_HOOK include/linux/netfilter.h:295 [inline] ip6_xmit+0x1258/0x1e80 net/ipv6/ip6_output.c:280 sctp_v6_xmit+0xbf3/0xfe0 net/sctp/ipv6.c:223 sctp_packet_transmit+0x1f44/0x32f0 net/sctp/output.c:627 sctp_packet_singleton net/sctp/outqueue.c:773 [inline] sctp_outq_flush_ctrl.constprop.0+0x6d3/0xc40 net/sctp/outqueue.c:904 sctp_outq_flush+0xf3/0x2580 net/sctp/outqueue.c:1186 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1801 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1185 [inline] sctp_do_sm+0x74e/0x5120 net/sctp/sm_sideeffect.c:1156 sctp_primitive_ASSOCIATE+0x98/0xc0 net/sctp/primitive.c:73 sctp_sendmsg_to_asoc+0xb8b/0x2180 net/sctp/socket.c:1823 sctp_sendmsg+0x103b/0x1d30 net/sctp/socket.c:2013 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:817 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:671 __sys_sendto+0x21c/0x320 net/socket.c:1992 __do_sys_sendto net/socket.c:2004 [inline] __se_sys_sendto net/socket.c:2000 [inline] __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45deb9 Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f86c2aa0c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000000000002e940 RCX: 000000000045deb9 RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000000003 RBP: 000000000118bf78 R08: 000000002005ffe4 R09: 000000000000001c R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffcacd5a88f R14: 00007f86c2aa19c0 R15: 000000000118bf2c Allocated by task 4905: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:506 [inline] slab_alloc_node mm/slub.c:2889 [inline] slab_alloc mm/slub.c:2897 [inline] kmem_cache_alloc+0x122/0x460 mm/slub.c:2902 getname_flags.part.0+0x50/0x4f0 fs/namei.c:138 getname_flags fs/namei.c:2647 [inline] user_path_at_empty+0xa1/0x100 fs/namei.c:2647 user_path_at include/linux/namei.h:59 [inline] vfs_statx+0x142/0x390 fs/stat.c:185 vfs_fstatat fs/stat.c:207 [inline] vfs_lstat include/linux/fs.h:3108 [inline] __do_sys_newlstat+0x91/0x110 fs/stat.c:362 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 4905: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0x102/0x140 mm/kasan/common.c:422 slab_free_hook mm/slub.c:1544 [inline] slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1577 slab_free mm/slub.c:3140 [inline] kmem_cache_free+0x82/0x350 mm/slub.c:3156 putname+0xe1/0x120 fs/namei.c:259 filename_lookup+0x3b1/0x560 fs/namei.c:2377 user_path_at include/linux/namei.h:59 [inline] vfs_statx+0x142/0x390 fs/stat.c:185 vfs_fstatat fs/stat.c:207 [inline] vfs_lstat include/linux/fs.h:3108 [inline] __do_sys_newlstat+0x91/0x110 fs/stat.c:362 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88802b0d8000 which belongs to the cache names_cache of size 4096 The buggy address is located 2223 bytes inside of 4096-byte region [ffff88802b0d8000, ffff88802b0d9000) The buggy address belongs to the page: page:000000001645020d refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b0d8 head:000000001645020d order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head) raw: 00fff00000010200 0000000000000000 0000000200000001 ffff8880101c6280 raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88802b0d8780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802b0d8800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802b0d8880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802b0d8900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802b0d8980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================