CVE-2024-50033 slip: make slhc_remember() more robust against malicious packets
A missing packet size check in the Linux kernel SLIP driver allows attackers to trigger uninitialized memory reads, potentially disclosing sensitive kernel data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-50033?
CVE-2024-50033 is a critical vulnerability in Linux kernel, published on 21 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
slip: make slhc_remember() more robust against malicious packets
syzbot found that slhc_remember() was missing checks against malicious packets [1].
slhc_remember() only checked the size of the packet was at least 20, which is not good enough.
We need to make sure the packet includes the IPv4 and TCP header that are supposed to be carried.
Add iph and th pointers to make the code more readable.
[1]
BUG: KMSAN: uninit-value in slhc_remember+0x2e8/0x7b0 drivers/net/slip/slhc.c:666 slhc_remember+0x2e8/0x7b0 drivers/net/slip/slhc.c:666 ppp_receive_nonmp_frame+0xe45/0x35e0 drivers/net/ppp/ppp_generic.c:2455 ppp_receive_frame drivers/net/ppp/ppp_generic.c:2372 [inline] ppp_do_recv+0x65f/0x40d0 drivers/net/ppp/ppp_generic.c:2212 ppp_input+0x7dc/0xe60 drivers/net/ppp/ppp_generic.c:2327 pppoe_rcv_core+0x1d3/0x720 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv+0x13b/0x420 include/net/sock.h:1113 __release_sock+0x1da/0x330 net/core/sock.c:3072 release_sock+0x6b/0x250 net/core/sock.c:3626 pppoe_sendmsg+0x2b8/0xb90 drivers/net/ppp/pppoe.c:903 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:744 ____sys_sendmsg+0x903/0xb60 net/socket.c:2602 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2656 __sys_sendmmsg+0x3c1/0x960 net/socket.c:2742 __do_sys_sendmmsg net/socket.c:2771 [inline] __se_sys_sendmmsg net/socket.c:2768 [inline] __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2768 x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
Uninit was created at: slab_post_alloc_hook mm/slub.c:4091 [inline] slab_alloc_node mm/slub.c:4134 [inline] kmem_cache_alloc_node_noprof+0x6bf/0xb80 mm/slub.c:4186 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:587 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:678 alloc_skb include/linux/skbuff.h:1322 [inline] sock_wmalloc+0xfe/0x1a0 net/core/sock.c:2732 pppoe_sendmsg+0x3a7/0xb90 drivers/net/ppp/pppoe.c:867 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:744 ____sys_sendmsg+0x903/0xb60 net/socket.c:2602 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2656 __sys_sendmmsg+0x3c1/0x960 net/socket.c:2742 __do_sys_sendmmsg net/socket.c:2771 [inline] __se_sys_sendmmsg net/socket.c:2768 [inline] __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2768 x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
CPU: 0 UID: 0 PID: 5460 Comm: syz.2.33 Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Weakness: CWE-908
Which versions are affected by CVE-2024-50033?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-50033?
Apply the vendor's patch.
Is CVE-2024-50033 being exploited?
There is no known exploitation of CVE-2024-50033 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-51153, AZL-51228, BELL-CVE-2024-50033, DEBIAN-CVE-2024-50033, GHSA-jpw5-f3qf-66fc, UBUNTU-CVE-2024-50033.