Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:[EOL][EOL]tcp: Clear tcp_sk(sk)->fastopen_rsk in tcp_disconnect().[EOL][EOL]syzbot reported the splat below where a socket had tcp_sk(sk)->fastopen_rsk[EOL]in the TCP_ESTABLISHED state. [0][EOL][EOL]syzbot reused the server-side TCP Fast Open socket as a new client before[EOL]the TFO socket completes 3WHS:[EOL][EOL]  1. accept()[EOL]  2. connect(AF_UNSPEC)[EOL]  3. connect() to another destination[EOL][EOL]As of accept(), sk->sk_state is TCP_SYN_RECV, and tcp_disconnect() changes[EOL]it to TCP_CLOSE and makes connect() possible, which restarts timers.[EOL][EOL]Since tcp_disconnect() forgot to clear tcp_sk(sk)->fastopen_rsk, the[EOL]retransmit timer triggered the warning and the intended packet was not[EOL]retransmitted.[EOL][EOL]Let's call reqsk_fastopen_remove() in tcp_disconnect().[EOL][EOL][0]:[EOL]WARNING: CPU: 2 PID: 0 at net/ipv4/tcp_timer.c:542 tcp_retransmit_timer (net/ipv4/tcp_timer.c:542 (discriminator 7))[EOL]Modules linked in:[EOL]CPU: 2 UID: 0 PID: 0 Comm: swapper/2 Not tainted 6.17.0-rc5-g201825fb4278 #62 PREEMPT(voluntary)[EOL]Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014[EOL]RIP: 0010:tcp_retransmit_timer (net/ipv4/tcp_timer.c:542 (discriminator 7))[EOL]Code: 41 55 41 54 55 53 48 8b af b8 08 00 00 48 89 fb 48 85 ed 0f 84 55 01 00 00 0f b6 47 12 3c 03 74 0c 0f b6 47 12 3c 04 74 04 90 <0f> 0b 90 48 8b 85 c0 00 00 00 48 89 ef 48 8b 40 30 e8 6a 4f 06 3e[EOL]RSP: 0018:ffffc900002f8d40 EFLAGS: 00010293[EOL]RAX: 0000000000000002 RBX: ffff888106911400 RCX: 0000000000000017[EOL]RDX: 0000000002517619 RSI: ffffffff83764080 RDI: ffff888106911400[EOL]RBP: ffff888106d5c000 R08: 0000000000000001 R09: ffffc900002f8de8[EOL]R10: 00000000000000c2 R11: ffffc900002f8ff8 R12: ffff888106911540[EOL]R13: ffff888106911480 R14: ffff888106911840 R15: ffffc900002f8de0[EOL]FS:  0000000000000000(0000) GS:ffff88907b768000(0000) knlGS:0000000000000000[EOL]CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033[EOL]CR2: 00007f8044d69d90 CR3: 0000000002c30003 CR4: 0000000000370ef0[EOL]Call Trace:[EOL] <IRQ>[EOL] tcp_write_timer (net/ipv4/tcp_timer.c:738)[EOL] call_timer_fn (kernel/time/timer.c:1747)[EOL] __run_timers (kernel/time/timer.c:1799 kernel/time/timer.c:2372)[EOL] timer_expire_remote (kernel/time/timer.c:2385 kernel/time/timer.c:2376 kernel/time/timer.c:2135)[EOL] tmigr_handle_remote_up (kernel/time/timer_migration.c:944 kernel/time/timer_migration.c:1035)[EOL] __walk_groups.isra.0 (kernel/time/timer_migration.c:533 (discriminator 1))[EOL] tmigr_handle_remote (kernel/time/timer_migration.c:1096)[EOL] handle_softirqs (./arch/x86/include/asm/jump_label.h:36 ./include/trace/events/irq.h:142 kernel/softirq.c:580)[EOL] irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680 kernel/softirq.c:696)[EOL] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 (discriminator 35) arch/x86/kernel/apic/apic.c:1050 (discriminator 35))[EOL] </IRQ>