Messages in this thread | | | From | Ozgur <> | Subject | Re: KASAN: slab-out-of-bounds Write in tcp_v6_syn_recv_sock | Date | Wed, 03 Jan 2018 23:55:54 +0300 |
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03.01.2018, 21:57, "Cong Wang" <xiyou.wangcong@gmail.com>: > On Tue, Jan 2, 2018 at 3:58 PM, syzbot > <syzbot+6dc95bddc6976b800b0b@syzkaller.appspotmail.com> wrote: >> Hello, >> >> syzkaller hit the following crash on >> 61233580f1f33c50e159c50e24d80ffd2ba2e06b >> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master >> compiler: gcc (GCC) 7.1.1 20170620 >> .config is attached >> Raw console output is attached. >> C reproducer is attached >> syzkaller reproducer is attached. See https://goo.gl/kgGztJ >> for information about syzkaller reproducers >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+6dc95bddc6976b800b0b@syzkaller.appspotmail.com >> It will help syzbot understand when the bug is fixed. See footer for >> details. >> If you forward the report, please keep this part and the footer. >> >> TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending >> cookies. Check SNMP counters. >> ================================================================== >> BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:344 [inline] >> BUG: KASAN: slab-out-of-bounds in tcp_v6_syn_recv_sock+0x628/0x23a0 >> net/ipv6/tcp_ipv6.c:1144 >> Write of size 160 at addr ffff8801cbdd7460 by task syzkaller545407/3196 >> >> CPU: 1 PID: 3196 Comm: syzkaller545407 Not tainted 4.15.0-rc5+ #241 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> Google 01/01/2011 >> Call Trace: >> <IRQ> >> __dump_stack lib/dump_stack.c:17 [inline] >> dump_stack+0x194/0x257 lib/dump_stack.c:53 >> print_address_description+0x73/0x250 mm/kasan/report.c:252 >> kasan_report_error mm/kasan/report.c:351 [inline] >> kasan_report+0x25b/0x340 mm/kasan/report.c:409 >> check_memory_region_inline mm/kasan/kasan.c:260 [inline] >> check_memory_region+0x137/0x190 mm/kasan/kasan.c:267 >> memcpy+0x37/0x50 mm/kasan/kasan.c:303 >> memcpy include/linux/string.h:344 [inline] >> tcp_v6_syn_recv_sock+0x628/0x23a0 net/ipv6/tcp_ipv6.c:1144 > > tls_init() changes sk->sk_prot from IPv6 to IPv4, which leads > to this bug. I guess IPv6 is not supported for TLS? If so, need > a check on proto in tls_init()...
Hello,
I think IPv6 supports with TLS. There was a previously posted commit by Mellanox:
https://patchwork.ozlabs.org/patch/801530/
Ozgur
>> tcp_get_cookie_sock+0x102/0x540 net/ipv4/syncookies.c:213 >> cookie_v6_check+0x177d/0x2160 net/ipv6/syncookies.c:255 >> tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1008 [inline] >> tcp_v6_do_rcv+0xe4d/0x11c0 net/ipv6/tcp_ipv6.c:1316 >> tcp_v6_rcv+0x22ee/0x2b40 net/ipv6/tcp_ipv6.c:1510 >> ip6_input_finish+0x36f/0x1700 net/ipv6/ip6_input.c:284 >> NF_HOOK include/linux/netfilter.h:250 [inline] >> ip6_input+0xe9/0x560 net/ipv6/ip6_input.c:327 >> dst_input include/net/dst.h:466 [inline] >> ip6_rcv_finish+0x1a9/0x7a0 net/ipv6/ip6_input.c:71 >> NF_HOOK include/linux/netfilter.h:250 [inline] >> ipv6_rcv+0xf1f/0x1f80 net/ipv6/ip6_input.c:208 >> __netif_receive_skb_core+0x1a3e/0x3450 net/core/dev.c:4461 >> __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4526 >> process_backlog+0x203/0x740 net/core/dev.c:5205 >> napi_poll net/core/dev.c:5603 [inline] >> net_rx_action+0x792/0x1910 net/core/dev.c:5669 >> __do_softirq+0x2d7/0xb85 kernel/softirq.c:285 >> do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1115 >> </IRQ> >> do_softirq.part.21+0x14d/0x190 kernel/softirq.c:329 >> do_softirq kernel/softirq.c:177 [inline] >> __local_bh_enable_ip+0x1ee/0x230 kernel/softirq.c:182 >> local_bh_enable include/linux/bottom_half.h:32 [inline] >> rcu_read_unlock_bh include/linux/rcupdate.h:727 [inline] >> ip6_finish_output2+0xba6/0x2390 net/ipv6/ip6_output.c:121 >> ip6_finish_output+0x2f9/0x920 net/ipv6/ip6_output.c:146 >> NF_HOOK_COND include/linux/netfilter.h:239 [inline] >> ip6_output+0x1eb/0x840 net/ipv6/ip6_output.c:163 >> dst_output include/net/dst.h:460 [inline] >> NF_HOOK include/linux/netfilter.h:250 [inline] >> ip6_xmit+0xd75/0x2080 net/ipv6/ip6_output.c:269 >> inet6_csk_xmit+0x2fc/0x580 net/ipv6/inet6_connection_sock.c:139 >> tcp_transmit_skb+0x1b12/0x38b0 net/ipv4/tcp_output.c:1176 >> tcp_write_xmit+0x680/0x5190 net/ipv4/tcp_output.c:2367 >> __tcp_push_pending_frames+0xa0/0x250 net/ipv4/tcp_output.c:2543 >> tcp_send_fin+0x1b0/0xd20 net/ipv4/tcp_output.c:3087 >> tcp_close+0xbe0/0xfc0 net/ipv4/tcp.c:2234 >> inet_release+0xed/0x1c0 net/ipv4/af_inet.c:426 >> inet6_release+0x50/0x70 net/ipv6/af_inet6.c:432 >> sock_release+0x8d/0x1e0 net/socket.c:600 >> sock_close+0x16/0x20 net/socket.c:1129 >> __fput+0x327/0x7e0 fs/file_table.c:210 >> ____fput+0x15/0x20 fs/file_table.c:244 >> task_work_run+0x199/0x270 kernel/task_work.c:113 >> exit_task_work include/linux/task_work.h:22 [inline] >> do_exit+0x9bb/0x1ad0 kernel/exit.c:865 >> do_group_exit+0x149/0x400 kernel/exit.c:968 >> get_signal+0x73f/0x16c0 kernel/signal.c:2335 >> do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809 >> exit_to_usermode_loop+0x214/0x310 arch/x86/entry/common.c:158 >> prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] >> syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264 >> entry_SYSCALL_64_fastpath+0x94/0x96 >> RIP: 0033:0x4456e9 >> RSP: 002b:00007fb4de631da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca >> RAX: fffffffffffffe00 RBX: 00000000006dac3c RCX: 00000000004456e9 >> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000006dac3c >> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac38 >> R13: 0100000000000000 R14: 00007fb4de6329c0 R15: 0000000000000009 >> >> Allocated by task 3196: >> save_stack+0x43/0xd0 mm/kasan/kasan.c:447 >> set_track mm/kasan/kasan.c:459 [inline] >> kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 >> kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 >> kmem_cache_alloc+0x12e/0x760 mm/slab.c:3544 >> sk_prot_alloc+0x65/0x2a0 net/core/sock.c:1463 >> sk_clone_lock+0x152/0x1570 net/core/sock.c:1649 >> inet_csk_clone_lock+0x92/0x4f0 net/ipv4/inet_connection_sock.c:781 >> tcp_create_openreq_child+0x9b/0x1b70 net/ipv4/tcp_minisocks.c:449 >> tcp_v6_syn_recv_sock+0x22d/0x23a0 net/ipv6/tcp_ipv6.c:1123 >> tcp_get_cookie_sock+0x102/0x540 net/ipv4/syncookies.c:213 >> cookie_v6_check+0x177d/0x2160 net/ipv6/syncookies.c:255 >> tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1008 [inline] >> tcp_v6_do_rcv+0xe4d/0x11c0 net/ipv6/tcp_ipv6.c:1316 >> tcp_v6_rcv+0x22ee/0x2b40 net/ipv6/tcp_ipv6.c:1510 >> ip6_input_finish+0x36f/0x1700 net/ipv6/ip6_input.c:284 >> NF_HOOK include/linux/netfilter.h:250 [inline] >> ip6_input+0xe9/0x560 net/ipv6/ip6_input.c:327 >> dst_input include/net/dst.h:466 [inline] >> ip6_rcv_finish+0x1a9/0x7a0 net/ipv6/ip6_input.c:71 >> NF_HOOK include/linux/netfilter.h:250 [inline] >> ipv6_rcv+0xf1f/0x1f80 net/ipv6/ip6_input.c:208 >> __netif_receive_skb_core+0x1a3e/0x3450 net/core/dev.c:4461 >> __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4526 >> process_backlog+0x203/0x740 net/core/dev.c:5205 >> napi_poll net/core/dev.c:5603 [inline] >> net_rx_action+0x792/0x1910 net/core/dev.c:5669 >> __do_softirq+0x2d7/0xb85 kernel/softirq.c:285 >> >> Freed by task 0: >> (stack is not available) >> >> The buggy address belongs to the object at ffff8801cbdd6a80 >> which belongs to the cache TCP of size 2528 >> The buggy address is located 0 bytes to the right of >> 2528-byte region [ffff8801cbdd6a80, ffff8801cbdd7460) >> The buggy address belongs to the page: >> page:000000006145927c count:1 mapcount:0 mapping:00000000d41dd7c1 >> index:0xffff8801cbdd7ffd compound_mapcount: 0 >> flags: 0x2fffc0000008100(slab|head) >> raw: 02fffc0000008100 ffff8801cbdd6000 ffff8801cbdd7ffd 0000000100000003 >> raw: ffffea00074ef120 ffff8801d82b7248 ffff8801d798b640 0000000000000000 >> page dumped because: kasan: bad access detected >> >> Memory state around the buggy address: >> ffff8801cbdd7300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >> ffff8801cbdd7380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >>> ffff8801cbdd7400: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc >> >> ^ >> ffff8801cbdd7480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff8801cbdd7500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >> ================================================================== >> >> --- >> This bug is generated by a dumb bot. It may contain errors. >> See https://goo.gl/tpsmEJ for details. >> Direct all questions to syzkaller@googlegroups.com. >> >> syzbot will keep track of this bug report. >> If you forgot to add the Reported-by tag, once the fix for this bug is >> merged >> into any tree, please reply to this email with: >> #syz fix: exact-commit-title >> If you want to test a patch for this bug, please reply with: >> #syz test: git://repo/address.git branch >> and provide the patch inline or as an attachment. >> To mark this as a duplicate of another syzbot report, please reply with: >> #syz dup: exact-subject-of-another-report >> If it's a one-off invalid bug report, please reply with: >> #syz invalid >> Note: if the crash happens again, it will cause creation of a new bug >> report. >> Note: all commands must start from beginning of the line in the email body.
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