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

Weakness

The product uses or accesses a resource that has not been initialized.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/0184bf0a349f4cf9e663abbe862ff280e8e4dfa2
• https://git.kernel.org/stable/c/61cf1c739f08190a4cbf047b9fbb192a94d87e3f
• https://git.kernel.org/stable/c/7094a5fd20ab66028f1da7f06e0f2692d70346f9
• https://git.kernel.org/stable/c/76965648fe6858db7c5f3c700fef7aa5f124ca1c
• https://git.kernel.org/stable/c/7ef519c8efde152e0d632337f2994f6921e0b7e4
• https://git.kernel.org/stable/c/8366720519ea8d322a20780debdfd23d9fc0904a
• https://git.kernel.org/stable/c/d6f487e0704de2f2d15f8dd5d7d723210f2b2fdb
• https://git.kernel.org/stable/c/f9b2010e8af49fac9d9562146fb81744d8a9b051
• https://git.kernel.org/stable/c/0184bf0a349f4cf9e663abbe862ff280e8e4dfa2
• https://git.kernel.org/stable/c/61cf1c739f08190a4cbf047b9fbb192a94d87e3f
• https://git.kernel.org/stable/c/7094a5fd20ab66028f1da7f06e0f2692d70346f9
• https://git.kernel.org/stable/c/76965648fe6858db7c5f3c700fef7aa5f124ca1c
• https://git.kernel.org/stable/c/7ef519c8efde152e0d632337f2994f6921e0b7e4
• https://git.kernel.org/stable/c/8366720519ea8d322a20780debdfd23d9fc0904a
• https://git.kernel.org/stable/c/d6f487e0704de2f2d15f8dd5d7d723210f2b2fdb
• https://git.kernel.org/stable/c/f9b2010e8af49fac9d9562146fb81744d8a9b051
• https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html