Hello, syzbot found the following issue on: HEAD commit: 0f4b9289bad3 Merge tag 'docs-5.15-2' of git://git.lwn.net/.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17e95663300000 kernel config: https://syzkaller.appspot.com/x/.config?x=ddf81d5d49fe3452 dashboard link: https://syzkaller.appspot.com/bug?extid=f31660cf279b0557160c compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17f78feb300000 The issue was bisected to: commit 6001a930ce0378b62210d4f83583fc88a903d89d Author: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Date: Mon Feb 15 11:28:07 2021 +0000 netfilter: nftables: introduce table ownership bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15f4170b300000 final oops: https://syzkaller.appspot.com/x/report.txt?x=17f4170b300000 console output: https://syzkaller.appspot.com/x/log.txt?x=13f4170b300000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+f31660cf279b0557160c@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 6001a930ce03 ("netfilter: nftables: introduce table ownership") ================================================================== BUG: KASAN: use-after-free in memcmp+0x18f/0x1c0 lib/string.c:955 Read of size 1 at addr ffff88806ef7e690 by task syz-executor.0/16206 CPU: 1 PID: 16206 Comm: syz-executor.0 Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:256 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 memcmp+0x18f/0x1c0 lib/string.c:955 memcmp include/linux/fortify-string.h:235 [inline] nla_strcmp+0xf2/0x130 lib/nlattr.c:836 nft_table_lookup.part.0+0x1a2/0x460 net/netfilter/nf_tables_api.c:570 nft_table_lookup net/netfilter/nf_tables_api.c:4064 [inline] nf_tables_getset+0x1b3/0x860 net/netfilter/nf_tables_api.c:4064 nfnetlink_rcv_msg+0x659/0x13f0 net/netfilter/nfnetlink.c:285 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504 nfnetlink_rcv+0x1ac/0x420 net/netfilter/nfnetlink.c:654 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2492 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f34c684e188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000020000d80 RDI: 0000000000000004 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffdd7170d4f R14: 00007f34c684e300 R15: 0000000000022000 Allocated by task 16206: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] ____kasan_kmalloc mm/kasan/common.c:472 [inline] __kasan_kmalloc+0xa4/0xd0 mm/kasan/common.c:522 kmalloc include/linux/slab.h:596 [inline] nla_strdup+0xc8/0x150 lib/nlattr.c:769 nf_tables_newtable+0xe5e/0x1b40 net/netfilter/nf_tables_api.c:1116 nfnetlink_rcv_batch+0x1710/0x25f0 net/netfilter/nfnetlink.c:513 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:634 [inline] nfnetlink_rcv+0x3af/0x420 net/netfilter/nfnetlink.c:652 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2492 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 16205: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1700 [inline] slab_free_freelist_hook+0x81/0x190 mm/slub.c:1725 slab_free mm/slub.c:3483 [inline] kfree+0xe4/0x530 mm/slub.c:4543 nf_tables_table_destroy+0xd2/0x1b0 net/netfilter/nf_tables_api.c:1313 __nft_release_table+0xabc/0xe30 net/netfilter/nf_tables_api.c:9603 nft_rcv_nl_event+0x4af/0x590 net/netfilter/nf_tables_api.c:9645 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83 blocking_notifier_call_chain kernel/notifier.c:318 [inline] blocking_notifier_call_chain+0x67/0x90 kernel/notifier.c:306 netlink_release+0xcb8/0x1dd0 net/netlink/af_netlink.c:785 __sock_release+0xcd/0x280 net/socket.c:649 sock_close+0x18/0x20 net/socket.c:1314 __fput+0x288/0x9f0 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:175 [inline] exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:209 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff88806ef7e690 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes inside of 8-byte region [ffff88806ef7e690, ffff88806ef7e698) The buggy address belongs to the page: page:ffffea0001bbdf80 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88806ef7ee10 pfn:0x6ef7e flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea00004deb00 0000000300000003 ffff888010c41280 raw: ffff88806ef7ee10 0000000080660054 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 6577, ts 1160917309588, free_ts 1160767773568 prep_new_page mm/page_alloc.c:2424 [inline] get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4151 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5373 alloc_pages+0x1a7/0x300 mm/mempolicy.c:2291 alloc_slab_page mm/slub.c:1763 [inline] allocate_slab mm/slub.c:1900 [inline] new_slab+0x319/0x490 mm/slub.c:1963 ___slab_alloc+0x921/0xfe0 mm/slub.c:2994 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3081 slab_alloc_node mm/slub.c:3172 [inline] __kmalloc_node+0x2d2/0x370 mm/slub.c:4435 kmalloc_node include/linux/slab.h:614 [inline] __vmalloc_area_node mm/vmalloc.c:2903 [inline] __vmalloc_node_range+0x5ec/0x9e0 mm/vmalloc.c:3020 __vmalloc_node mm/vmalloc.c:3069 [inline] vzalloc+0x67/0x80 mm/vmalloc.c:3139 do_arpt_get_ctl+0x5f6/0x8f0 net/ipv4/netfilter/arp_tables.c:659 nf_getsockopt+0x72/0xd0 net/netfilter/nf_sockopt.c:116 ip_getsockopt net/ipv4/ip_sockglue.c:1777 [inline] ip_getsockopt+0x164/0x1c0 net/ipv4/ip_sockglue.c:1756 tcp_getsockopt+0x86/0xd0 net/ipv4/tcp.c:4254 __sys_getsockopt+0x21f/0x5f0 net/socket.c:2220 __do_sys_getsockopt net/socket.c:2235 [inline] __se_sys_getsockopt net/socket.c:2232 [inline] __x64_sys_getsockopt+0xba/0x150 net/socket.c:2232 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1338 [inline] free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1389 free_unref_page_prepare mm/page_alloc.c:3315 [inline] free_unref_page_list+0x1a1/0x1010 mm/page_alloc.c:3431 release_pages+0x830/0x20b0 mm/swap.c:950 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:242 [inline] tlb_flush_mmu mm/mmu_gather.c:249 [inline] tlb_finish_mmu+0x165/0x8c0 mm/mmu_gather.c:340 exit_mmap+0x1ea/0x620 mm/mmap.c:3173 __mmput+0x122/0x4b0 kernel/fork.c:1114 mmput+0x58/0x60 kernel/fork.c:1135 exit_mm kernel/exit.c:501 [inline] do_exit+0xabc/0x2a30 kernel/exit.c:812 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x47f/0x2160 kernel/signal.c:2868 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:865 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:209 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae Memory state around the buggy address: ffff88806ef7e580: fc fc fc fc fb fc fc fc fc fb fc fc fc fc fb fc ffff88806ef7e600: fc fc fc fb fc fc fc fc fb fc fc fc fc fb fc fc >ffff88806ef7e680: fc fc fa fc fc fc fc fa fc fc fc fc fa fc fc fc ^ ffff88806ef7e700: fc fa fc fc fc fc fa fc fc fc fc fa fc fc fc fc ffff88806ef7e780: fa fc fc fc fc fa fc fc fc fc fa fc fc fc fc fa ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
