inet: clear num_timeout reqsk_alloc()
KMSAN caught uninit-value in tcp_create_openreq_child() [1] This is caused by a recent change, combined by the fact that TCP cleared num_timeout, num_retrans and sk fields only when a request socket was about to be queued. Under syncookie mode, a temporary request socket is used, and req->num_timeout could contain garbage. Lets clear these three fields sooner, there is really no point trying to defer this and risk other bugs. [1] BUG: KMSAN: uninit-value in tcp_create_openreq_child+0x157f/0x1cc0 net/ipv4/tcp_minisocks.c:526 CPU: 1 PID: 13357 Comm: syz-executor591 Not tainted 5.2.0-rc4+ #3 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x191/0x1f0 lib/dump_stack.c:113 kmsan_report+0x162/0x2d0 mm/kmsan/kmsan.c:611 __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:304 tcp_create_openreq_child+0x157f/0x1cc0 net/ipv4/tcp_minisocks.c:526 tcp_v6_syn_recv_sock+0x761/0x2d80 net/ipv6/tcp_ipv6.c:1152 tcp_get_cookie_sock+0x16e/0x6b0 net/ipv4/syncookies.c:209 cookie_v6_check+0x27e0/0x29a0 net/ipv6/syncookies.c:252 tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1039 [inline] tcp_v6_do_rcv+0xf1c/0x1ce0 net/ipv6/tcp_ipv6.c:1344 tcp_v6_rcv+0x60b7/0x6a30 net/ipv6/tcp_ipv6.c:1554 ip6_protocol_deliver_rcu+0x1433/0x22f0 net/ipv6/ip6_input.c:397 ip6_input_finish net/ipv6/ip6_input.c:438 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ip6_input+0x2af/0x340 net/ipv6/ip6_input.c:447 dst_input include/net/dst.h:439 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ipv6_rcv+0x683/0x710 net/ipv6/ip6_input.c:272 __netif_receive_skb_one_core net/core/dev.c:4981 [inline] __netif_receive_skb net/core/dev.c:5095 [inline] process_backlog+0x721/0x1410 net/core/dev.c:5906 napi_poll net/core/dev.c:6329 [inline] net_rx_action+0x738/0x1940 net/core/dev.c:6395 __do_softirq+0x4ad/0x858 kernel/softirq.c:293 do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1052 </IRQ> do_softirq kernel/softirq.c:338 [inline] __local_bh_enable_ip+0x199/0x1e0 kernel/softirq.c:190 local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32 rcu_read_unlock_bh include/linux/rcupdate.h:682 [inline] ip6_finish_output2+0x213f/0x2670 net/ipv6/ip6_output.c:117 ip6_finish_output+0xae4/0xbc0 net/ipv6/ip6_output.c:150 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip6_output+0x5d3/0x720 net/ipv6/ip6_output.c:167 dst_output include/net/dst.h:433 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ip6_xmit+0x1f53/0x2650 net/ipv6/ip6_output.c:271 inet6_csk_xmit+0x3df/0x4f0 net/ipv6/inet6_connection_sock.c:135 __tcp_transmit_skb+0x4076/0x5b40 net/ipv4/tcp_output.c:1156 tcp_transmit_skb net/ipv4/tcp_output.c:1172 [inline] tcp_write_xmit+0x39a9/0xa730 net/ipv4/tcp_output.c:2397 __tcp_push_pending_frames+0x124/0x4e0 net/ipv4/tcp_output.c:2573 tcp_send_fin+0xd43/0x1540 net/ipv4/tcp_output.c:3118 tcp_close+0x16ba/0x1860 net/ipv4/tcp.c:2403 inet_release+0x1f7/0x270 net/ipv4/af_inet.c:427 inet6_release+0xaf/0x100 net/ipv6/af_inet6.c:470 __sock_release net/socket.c:601 [inline] sock_close+0x156/0x490 net/socket.c:1273 __fput+0x4c9/0xba0 fs/file_table.c:280 ____fput+0x37/0x40 fs/file_table.c:313 task_work_run+0x22e/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:185 [inline] exit_to_usermode_loop arch/x86/entry/common.c:168 [inline] prepare_exit_to_usermode+0x39d/0x4d0 arch/x86/entry/common.c:199 syscall_return_slowpath+0x90/0x5c0 arch/x86/entry/common.c:279 do_syscall_64+0xe2/0xf0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x401d50 Code: 01 f0 ff ff 0f 83 40 0d 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 83 3d dd 8d 2d 00 00 75 14 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 14 0d 00 00 c3 48 83 ec 08 e8 7a 02 00 00 RSP: 002b:00007fff1cf58cf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000401d50 RDX: 000000000000001c RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000004a9050 R08: 0000000020000040 R09: 000000000000001c R10: 0000000020004004 R11: 0000000000000246 R12: 0000000000402ef0 R13: 0000000000402f80 R14: 0000000000000000 R15: 0000000000000000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:201 [inline] kmsan_internal_poison_shadow+0x53/0xa0 mm/kmsan/kmsan.c:160 kmsan_kmalloc+0xa4/0x130 mm/kmsan/kmsan_hooks.c:177 kmem_cache_alloc+0x534/0xb00 mm/slub.c:2781 reqsk_alloc include/net/request_sock.h:84 [inline] inet_reqsk_alloc+0xa8/0x600 net/ipv4/tcp_input.c:6384 cookie_v6_check+0xadb/0x29a0 net/ipv6/syncookies.c:173 tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1039 [inline] tcp_v6_do_rcv+0xf1c/0x1ce0 net/ipv6/tcp_ipv6.c:1344 tcp_v6_rcv+0x60b7/0x6a30 net/ipv6/tcp_ipv6.c:1554 ip6_protocol_deliver_rcu+0x1433/0x22f0 net/ipv6/ip6_input.c:397 ip6_input_finish net/ipv6/ip6_input.c:438 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ip6_input+0x2af/0x340 net/ipv6/ip6_input.c:447 dst_input include/net/dst.h:439 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ipv6_rcv+0x683/0x710 net/ipv6/ip6_input.c:272 __netif_receive_skb_one_core net/core/dev.c:4981 [inline] __netif_receive_skb net/core/dev.c:5095 [inline] process_backlog+0x721/0x1410 net/core/dev.c:5906 napi_poll net/core/dev.c:6329 [inline] net_rx_action+0x738/0x1940 net/core/dev.c:6395 __do_softirq+0x4ad/0x858 kernel/softirq.c:293 do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1052 do_softirq kernel/softirq.c:338 [inline] __local_bh_enable_ip+0x199/0x1e0 kernel/softirq.c:190 local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32 rcu_read_unlock_bh include/linux/rcupdate.h:682 [inline] ip6_finish_output2+0x213f/0x2670 net/ipv6/ip6_output.c:117 ip6_finish_output+0xae4/0xbc0 net/ipv6/ip6_output.c:150 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip6_output+0x5d3/0x720 net/ipv6/ip6_output.c:167 dst_output include/net/dst.h:433 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ip6_xmit+0x1f53/0x2650 net/ipv6/ip6_output.c:271 inet6_csk_xmit+0x3df/0x4f0 net/ipv6/inet6_connection_sock.c:135 __tcp_transmit_skb+0x4076/0x5b40 net/ipv4/tcp_output.c:1156 tcp_transmit_skb net/ipv4/tcp_output.c:1172 [inline] tcp_write_xmit+0x39a9/0xa730 net/ipv4/tcp_output.c:2397 __tcp_push_pending_frames+0x124/0x4e0 net/ipv4/tcp_output.c:2573 tcp_send_fin+0xd43/0x1540 net/ipv4/tcp_output.c:3118 tcp_close+0x16ba/0x1860 net/ipv4/tcp.c:2403 inet_release+0x1f7/0x270 net/ipv4/af_inet.c:427 inet6_release+0xaf/0x100 net/ipv6/af_inet6.c:470 __sock_release net/socket.c:601 [inline] sock_close+0x156/0x490 net/socket.c:1273 __fput+0x4c9/0xba0 fs/file_table.c:280 ____fput+0x37/0x40 fs/file_table.c:313 task_work_run+0x22e/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:185 [inline] exit_to_usermode_loop arch/x86/entry/common.c:168 [inline] prepare_exit_to_usermode+0x39d/0x4d0 arch/x86/entry/common.c:199 syscall_return_slowpath+0x90/0x5c0 arch/x86/entry/common.c:279 do_syscall_64+0xe2/0xf0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x63/0xe7 Fixes: 336c39a0 ("tcp: undo init congestion window on false SYNACK timeout") Signed-off-by:Eric Dumazet <edumazet@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Reported-by:
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