CVE-2024-42106

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

inet_diag: Initialize pad field in struct inet_diag_req_v2

KMSAN reported uninit-value access in raw_lookup() [1]. Diag for raw

sockets uses the pad field in struct inet_diag_req_v2 for the

underlying protocol. This field corresponds to the sdiag_raw_protocol

field in struct inet_diag_req_raw.

inet_diag_get_exact_compat() converts inet_diag_req to

inet_diag_req_v2, but leaves the pad field uninitialized. So the issue

occurs when raw_lookup() accesses the sdiag_raw_protocol field.

Fix this by initializing the pad field in

inet_diag_get_exact_compat(). Also, do the same fix in

inet_diag_dump_compat() to avoid the similar issue in the future.

[1]

BUG: KMSAN: uninit-value in raw_lookup net/ipv4/raw_diag.c:49 [inline]

BUG: KMSAN: uninit-value in raw_sock_get+0x657/0x800 net/ipv4/raw_diag.c:71

raw_lookup net/ipv4/raw_diag.c:49 [inline]

raw_sock_get+0x657/0x800 net/ipv4/raw_diag.c:71

raw_diag_dump_one+0xa1/0x660 net/ipv4/raw_diag.c:99

inet_diag_cmd_exact+0x7d9/0x980

inet_diag_get_exact_compat net/ipv4/inet_diag.c:1404 [inline]

inet_diag_rcv_msg_compat+0x469/0x530 net/ipv4/inet_diag.c:1426

sock_diag_rcv_msg+0x23d/0x740 net/core/sock_diag.c:282

netlink_rcv_skb+0x537/0x670 net/netlink/af_netlink.c:2564

sock_diag_rcv+0x35/0x40 net/core/sock_diag.c:297

netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]

netlink_unicast+0xe74/0x1240 net/netlink/af_netlink.c:1361

netlink_sendmsg+0x10c6/0x1260 net/netlink/af_netlink.c:1905

sock_sendmsg_nosec net/socket.c:730 [inline]

__sock_sendmsg+0x332/0x3d0 net/socket.c:745

____sys_sendmsg+0x7f0/0xb70 net/socket.c:2585

___sys_sendmsg+0x271/0x3b0 net/socket.c:2639

__sys_sendmsg net/socket.c:2668 [inline]

__do_sys_sendmsg net/socket.c:2677 [inline]

__se_sys_sendmsg net/socket.c:2675 [inline]

__x64_sys_sendmsg+0x27e/0x4a0 net/socket.c:2675

x64_sys_call+0x135e/0x3ce0 arch/x86/include/generated/asm/syscalls_64.h:47

do_syscall_x64 arch/x86/entry/common.c:52 [inline]

do_syscall_64+0xd9/0x1e0 arch/x86/entry/common.c:83

entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:

raw_sock_get+0x650/0x800 net/ipv4/raw_diag.c:71

raw_diag_dump_one+0xa1/0x660 net/ipv4/raw_diag.c:99

inet_diag_cmd_exact+0x7d9/0x980

inet_diag_get_exact_compat net/ipv4/inet_diag.c:1404 [inline]

inet_diag_rcv_msg_compat+0x469/0x530 net/ipv4/inet_diag.c:1426

sock_diag_rcv_msg+0x23d/0x740 net/core/sock_diag.c:282

netlink_rcv_skb+0x537/0x670 net/netlink/af_netlink.c:2564

sock_diag_rcv+0x35/0x40 net/core/sock_diag.c:297

netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]

netlink_unicast+0xe74/0x1240 net/netlink/af_netlink.c:1361

netlink_sendmsg+0x10c6/0x1260 net/netlink/af_netlink.c:1905

sock_sendmsg_nosec net/socket.c:730 [inline]

__sock_sendmsg+0x332/0x3d0 net/socket.c:745

____sys_sendmsg+0x7f0/0xb70 net/socket.c:2585

___sys_sendmsg+0x271/0x3b0 net/socket.c:2639

__sys_sendmsg net/socket.c:2668 [inline]

__do_sys_sendmsg net/socket.c:2677 [inline]

__se_sys_sendmsg net/socket.c:2675 [inline]

__x64_sys_sendmsg+0x27e/0x4a0 net/socket.c:2675

x64_sys_call+0x135e/0x3ce0 arch/x86/include/generated/asm/syscalls_64.h:47

do_syscall_x64 arch/x86/entry/common.c:52 [inline]

do_syscall_64+0xd9/0x1e0 arch/x86/entry/common.c:83

entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable req.i created at:

inet_diag_get_exact_compat net/ipv4/inet_diag.c:1396 [inline]

inet_diag_rcv_msg_compat+0x2a6/0x530 net/ipv4/inet_diag.c:1426

sock_diag_rcv_msg+0x23d/0x740 net/core/sock_diag.c:282

CPU: 1 PID: 8888 Comm: syz-executor.6 Not tainted 6.10.0-rc4-00217-g35bb670d65fc #32

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014