CVE-2023-53824

In the Linux kernel, the following vulnerability has been resolved:

netlink: annotate lockless accesses to nlk->max_recvmsg_len

syzbot reported a data-race in data-race in netlink_recvmsg() [1]

Indeed, netlink_recvmsg() can be run concurrently,

and netlink_dump() also needs protection.

[1]

BUG: KCSAN: data-race in netlink_recvmsg / netlink_recvmsg

read to 0xffff888141840b38 of 8 bytes by task 23057 on cpu 0:

netlink_recvmsg+0xea/0x730 net/netlink/af_netlink.c:1988

sock_recvmsg_nosec net/socket.c:1017 [inline]

sock_recvmsg net/socket.c:1038 [inline]

__sys_recvfrom+0x1ee/0x2e0 net/socket.c:2194

__do_sys_recvfrom net/socket.c:2212 [inline]

__se_sys_recvfrom net/socket.c:2208 [inline]

__x64_sys_recvfrom+0x78/0x90 net/socket.c:2208

do_syscall_x64 arch/x86/entry/common.c:50 [inline]

do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80

entry_SYSCALL_64_after_hwframe+0x63/0xcd

write to 0xffff888141840b38 of 8 bytes by task 23037 on cpu 1:

netlink_recvmsg+0x114/0x730 net/netlink/af_netlink.c:1989

sock_recvmsg_nosec net/socket.c:1017 [inline]

sock_recvmsg net/socket.c:1038 [inline]

____sys_recvmsg+0x156/0x310 net/socket.c:2720

___sys_recvmsg net/socket.c:2762 [inline]

do_recvmmsg+0x2e5/0x710 net/socket.c:2856

__sys_recvmmsg net/socket.c:2935 [inline]

__do_sys_recvmmsg net/socket.c:2958 [inline]

__se_sys_recvmmsg net/socket.c:2951 [inline]

__x64_sys_recvmmsg+0xe2/0x160 net/socket.c:2951

do_syscall_x64 arch/x86/entry/common.c:50 [inline]

do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80

entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000000000 -> 0x0000000000001000

Reported by Kernel Concurrency Sanitizer on:

CPU: 1 PID: 23037 Comm: syz-executor.2 Not tainted 6.3.0-rc4-syzkaller-00195-g5a57b48fdfcb #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023