CVE-2025-68291

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> mptcp: Initialise rcv_mss before calling tcp_send_active_reset() in mptcp_do_fastclose().<br /> <br /> syzbot reported divide-by-zero in __tcp_select_window() by<br /> MPTCP socket. [0]<br /> <br /> We had a similar issue for the bare TCP and fixed in commit<br /> 499350a5a6e7 ("tcp: initialize rcv_mss to TCP_MIN_MSS instead<br /> of 0").<br /> <br /> Let&amp;#39;s apply the same fix to mptcp_do_fastclose().<br /> <br /> [0]:<br /> Oops: divide error: 0000 [#1] SMP KASAN PTI<br /> CPU: 0 UID: 0 PID: 6068 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)<br /> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025<br /> RIP: 0010:__tcp_select_window+0x824/0x1320 net/ipv4/tcp_output.c:3336<br /> Code: ff ff ff 44 89 f1 d3 e0 89 c1 f7 d1 41 01 cc 41 21 c4 e9 a9 00 00 00 e8 ca 49 01 f8 e9 9c 00 00 00 e8 c0 49 01 f8 44 89 e0 99 7c 24 1c 41 29 d4 48 bb 00 00 00 00 00 fc ff df e9 80 00 00 00<br /> RSP: 0018:ffffc90003017640 EFLAGS: 00010293<br /> RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88807b469e40<br /> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000<br /> RBP: ffffc90003017730 R08: ffff888033268143 R09: 1ffff1100664d028<br /> R10: dffffc0000000000 R11: ffffed100664d029 R12: 0000000000000000<br /> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000<br /> FS: 000055557faa0500(0000) GS:ffff888126135000(0000) knlGS:0000000000000000<br /> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033<br /> CR2: 00007f64a1912ff8 CR3: 0000000072122000 CR4: 00000000003526f0<br /> Call Trace:<br /> <br /> tcp_select_window net/ipv4/tcp_output.c:281 [inline]<br /> __tcp_transmit_skb+0xbc7/0x3aa0 net/ipv4/tcp_output.c:1568<br /> tcp_transmit_skb net/ipv4/tcp_output.c:1649 [inline]<br /> tcp_send_active_reset+0x2d1/0x5b0 net/ipv4/tcp_output.c:3836<br /> mptcp_do_fastclose+0x27e/0x380 net/mptcp/protocol.c:2793<br /> mptcp_disconnect+0x238/0x710 net/mptcp/protocol.c:3253<br /> mptcp_sendmsg_fastopen+0x2f8/0x580 net/mptcp/protocol.c:1776<br /> mptcp_sendmsg+0x1774/0x1980 net/mptcp/protocol.c:1855<br /> sock_sendmsg_nosec net/socket.c:727 [inline]<br /> __sock_sendmsg+0xe5/0x270 net/socket.c:742<br /> __sys_sendto+0x3bd/0x520 net/socket.c:2244<br /> __do_sys_sendto net/socket.c:2251 [inline]<br /> __se_sys_sendto net/socket.c:2247 [inline]<br /> __x64_sys_sendto+0xde/0x100 net/socket.c:2247<br /> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]<br /> do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94<br /> entry_SYSCALL_64_after_hwframe+0x77/0x7f<br /> RIP: 0033:0x7f66e998f749<br /> 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 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48<br /> RSP: 002b:00007ffff9acedb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c<br /> RAX: ffffffffffffffda RBX: 00007f66e9be5fa0 RCX: 00007f66e998f749<br /> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003<br /> RBP: 00007ffff9acee10 R08: 0000000000000000 R09: 0000000000000000<br /> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001<br /> R13: 00007f66e9be5fa0 R14: 00007f66e9be5fa0 R15: 0000000000000006<br />