CVE-2025-38324

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> mpls: Use rcu_dereference_rtnl() in mpls_route_input_rcu().<br /> <br /> As syzbot reported [0], mpls_route_input_rcu() can be called<br /> from mpls_getroute(), where is under RTNL.<br /> <br /> net-&gt;mpls.platform_label is only updated under RTNL.<br /> <br /> Let&amp;#39;s use rcu_dereference_rtnl() in mpls_route_input_rcu() to<br /> silence the splat.<br /> <br /> [0]:<br /> WARNING: suspicious RCU usage<br /> 6.15.0-rc7-syzkaller-00082-g5cdb2c77c4c3 #0 Not tainted<br /> ----------------------------<br /> net/mpls/af_mpls.c:84 suspicious rcu_dereference_check() usage!<br /> <br /> other info that might help us debug this:<br /> <br /> rcu_scheduler_active = 2, debug_locks = 1<br /> 1 lock held by syz.2.4451/17730:<br /> #0: ffffffff9012a3e8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]<br /> #0: ffffffff9012a3e8 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x371/0xe90 net/core/rtnetlink.c:6961<br /> <br /> stack backtrace:<br /> CPU: 1 UID: 0 PID: 17730 Comm: syz.2.4451 Not tainted 6.15.0-rc7-syzkaller-00082-g5cdb2c77c4c3 #0 PREEMPT(full)<br /> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025<br /> Call Trace:<br /> <br /> __dump_stack lib/dump_stack.c:94 [inline]<br /> dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:120<br /> lockdep_rcu_suspicious+0x166/0x260 kernel/locking/lockdep.c:6865<br /> mpls_route_input_rcu+0x1d4/0x200 net/mpls/af_mpls.c:84<br /> mpls_getroute+0x621/0x1ea0 net/mpls/af_mpls.c:2381<br /> rtnetlink_rcv_msg+0x3c9/0xe90 net/core/rtnetlink.c:6964<br /> netlink_rcv_skb+0x16d/0x440 net/netlink/af_netlink.c:2534<br /> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]<br /> netlink_unicast+0x53a/0x7f0 net/netlink/af_netlink.c:1339<br /> netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883<br /> sock_sendmsg_nosec net/socket.c:712 [inline]<br /> __sock_sendmsg net/socket.c:727 [inline]<br /> ____sys_sendmsg+0xa98/0xc70 net/socket.c:2566<br /> ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620<br /> __sys_sendmmsg+0x200/0x420 net/socket.c:2709<br /> __do_sys_sendmmsg net/socket.c:2736 [inline]<br /> __se_sys_sendmmsg net/socket.c:2733 [inline]<br /> __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2733<br /> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]<br /> do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94<br /> entry_SYSCALL_64_after_hwframe+0x77/0x7f<br /> RIP: 0033:0x7f0a2818e969<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:00007f0a28f52038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133<br /> RAX: ffffffffffffffda RBX: 00007f0a283b5fa0 RCX: 00007f0a2818e969<br /> RDX: 0000000000000003 RSI: 0000200000000080 RDI: 0000000000000003<br /> RBP: 00007f0a28210ab1 R08: 0000000000000000 R09: 0000000000000000<br /> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000<br /> R13: 0000000000000000 R14: 00007f0a283b5fa0 R15: 00007ffce5e9f268<br />