CVE-2024-42272 sched: act_ct: take care of padding in struct zones_ht_key
A local attacker can read uninitialized kernel memory via the sched act_ct module due to improper handling of struct padding in hash table lookups.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-42272?
CVE-2024-42272 is a high-severity vulnerability in Linux kernel, published on 17 Aug 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
sched: act_ct: take care of padding in struct zones_ht_key
Blamed commit increased lookup key size from 2 bytes to 16 bytes, because zones_ht_key got a struct net pointer.
Make sure rhashtable_lookup() is not using the padding bytes which are not initialized.
BUG: KMSAN: uninit-value in rht_ptr_rcu include/linux/rhashtable.h:376 [inline] BUG: KMSAN: uninit-value in __rhashtable_lookup include/linux/rhashtable.h:607 [inline] BUG: KMSAN: uninit-value in rhashtable_lookup include/linux/rhashtable.h:646 [inline] BUG: KMSAN: uninit-value in rhashtable_lookup_fast include/linux/rhashtable.h:672 [inline] BUG: KMSAN: uninit-value in tcf_ct_flow_table_get+0x611/0x2260 net/sched/act_ct.c:329 rht_ptr_rcu include/linux/rhashtable.h:376 [inline] __rhashtable_lookup include/linux/rhashtable.h:607 [inline] rhashtable_lookup include/linux/rhashtable.h:646 [inline] rhashtable_lookup_fast include/linux/rhashtable.h:672 [inline] tcf_ct_flow_table_get+0x611/0x2260 net/sched/act_ct.c:329 tcf_ct_init+0xa67/0x2890 net/sched/act_ct.c:1408 tcf_action_init_1+0x6cc/0xb30 net/sched/act_api.c:1425 tcf_action_init+0x458/0xf00 net/sched/act_api.c:1488 tcf_action_add net/sched/act_api.c:2061 [inline] tc_ctl_action+0x4be/0x19d0 net/sched/act_api.c:2118 rtnetlink_rcv_msg+0x12fc/0x1410 net/core/rtnetlink.c:6647 netlink_rcv_skb+0x375/0x650 net/netlink/af_netlink.c:2550 rtnetlink_rcv+0x34/0x40 net/core/rtnetlink.c:6665 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline] netlink_unicast+0xf52/0x1260 net/netlink/af_netlink.c:1357 netlink_sendmsg+0x10da/0x11e0 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:745 ____sys_sendmsg+0x877/0xb60 net/socket.c:2597 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2651 __sys_sendmsg net/socket.c:2680 [inline] __do_sys_sendmsg net/socket.c:2689 [inline] __se_sys_sendmsg net/socket.c:2687 [inline] __x64_sys_sendmsg+0x307/0x4a0 net/socket.c:2687 x64_sys_call+0x2dd6/0x3c10 arch/x86/include/generated/asm/syscalls_64.h:47 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
Local variable key created at: tcf_ct_flow_table_get+0x4a/0x2260 net/sched/act_ct.c:324 tcf_ct_init+0xa67/0x2890 net/sched/act_ct.c:1408
Weakness: CWE-908
Which versions are affected by CVE-2024-42272?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-42272?
Apply the vendor's patch.
Is CVE-2024-42272 being exploited?
There is no known exploitation of CVE-2024-42272 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-49749, BELL-CVE-2024-42272, DEBIAN-CVE-2024-42272, GHSA-cfx8-vqq2-xr93, UBUNTU-CVE-2024-42272.