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

net/sched: act_skbmod: prevent kernel-infoleak

syzbot found that tcf_skbmod_dump() was copying four bytes
from kernel stack to user space [1].

The issue here is that 'struct tc_skbmod' has a four bytes hole.

We need to clear the structure before filling fields.

[1]
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline]
BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:29 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:271 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x366/0x2520 lib/iov_iter.c:185
instrument_copy_to_user include/linux/instrumented.h:114 [inline]
copy_to_user_iter lib/iov_iter.c:24 [inline]
iterate_ubuf include/linux/iov_iter.h:29 [inline]
iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
iterate_and_advance include/linux/iov_iter.h:271 [inline]
_copy_to_iter+0x366/0x2520 lib/iov_iter.c:185
copy_to_iter include/linux/uio.h:196 [inline]
simple_copy_to_iter net/core/datagram.c:532 [inline]
__skb_datagram_iter+0x185/0x1000 net/core/datagram.c:420
skb_copy_datagram_iter+0x5c/0x200 net/core/datagram.c:546
skb_copy_datagram_msg include/linux/skbuff.h:4050 [inline]
netlink_recvmsg+0x432/0x1610 net/netlink/af_netlink.c:1962
sock_recvmsg_nosec net/socket.c:1046 [inline]
sock_recvmsg+0x2c4/0x340 net/socket.c:1068
__sys_recvfrom+0x35a/0x5f0 net/socket.c:2242
__do_sys_recvfrom net/socket.c:2260 [inline]
__se_sys_recvfrom net/socket.c:2256 [inline]
__x64_sys_recvfrom+0x126/0x1d0 net/socket.c:2256
do_syscall_64+0xd5/0x1f0
entry_SYSCALL_64_after_hwframe+0x6d/0x75

Uninit was stored to memory at:
pskb_expand_head+0x30f/0x19d0 net/core/skbuff.c:2253
netlink_trim+0x2c2/0x330 net/netlink/af_netlink.c:1317
netlink_unicast+0x9f/0x1260 net/netlink/af_netlink.c:1351
nlmsg_unicast include/net/netlink.h:1144 [inline]
nlmsg_notify+0x21d/0x2f0 net/netlink/af_netlink.c:2610
rtnetlink_send+0x73/0x90 net/core/rtnetlink.c:741
rtnetlink_maybe_send include/linux/rtnetlink.h:17 [inline]
tcf_add_notify net/sched/act_api.c:2048 [inline]
tcf_action_add net/sched/act_api.c:2071 [inline]
tc_ctl_action+0x146e/0x19d0 net/sched/act_api.c:2119
rtnetlink_rcv_msg+0x1737/0x1900 net/core/rtnetlink.c:6595
netlink_rcv_skb+0x375/0x650 net/netlink/af_netlink.c:2559
rtnetlink_rcv+0x34/0x40 net/core/rtnetlink.c:6613
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0xf4c/0x1260 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x10df/0x11f0 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x30f/0x380 net/socket.c:745
____sys_sendmsg+0x877/0xb60 net/socket.c:2584
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline]
__do_sys_sendmsg net/socket.c:2676 [inline]
__se_sys_sendmsg net/socket.c:2674 [inline]
__x64_sys_sendmsg+0x307/0x4a0 net/socket.c:2674
do_syscall_64+0xd5/0x1f0
entry_SYSCALL_64_after_hwframe+0x6d/0x75

Uninit was stored to memory at:
__nla_put lib/nlattr.c:1041 [inline]
nla_put+0x1c6/0x230 lib/nlattr.c:1099
tcf_skbmod_dump+0x23f/0xc20 net/sched/act_skbmod.c:256
tcf_action_dump_old net/sched/act_api.c:1191 [inline]
tcf_action_dump_1+0x85e/0x970 net/sched/act_api.c:1227
tcf_action_dump+0x1fd/0x460 net/sched/act_api.c:1251
tca_get_fill+0x519/0x7a0 net/sched/act_api.c:1628
tcf_add_notify_msg net/sched/act_api.c:2023 [inline]
tcf_add_notify net/sched/act_api.c:2042 [inline]
tcf_action_add net/sched/act_api.c:2071 [inline]
tc_ctl_action+0x1365/0x19d0 net/sched/act_api.c:2119
rtnetlink_rcv_msg+0x1737/0x1900 net/core/rtnetlink.c:6595
netlink_rcv_skb+0x375/0x650 net/netlink/af_netli
---truncated---
Advisories
Source ID Title
Debian DLA Debian DLA DLA-3840-1 linux security update
Debian DLA Debian DLA DLA-3842-1 linux-5.10 security update
Ubuntu USN Ubuntu USN USN-6893-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6893-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6893-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6896-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6896-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6896-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6896-4 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6896-5 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6898-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6898-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6898-3 Linux kernel kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6898-4 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6917-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6918-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6919-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-6927-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7019-1 Linux kernel vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 11 Jul 2025 13:45:00 +0000

Type Values Removed Values Added
Metrics epss

{'score': 0.00058}

epss

{'score': 0.0006}


Fri, 22 Nov 2024 12:00:00 +0000


Tue, 05 Nov 2024 10:45:00 +0000


Thu, 08 Aug 2024 19:15:00 +0000

Type Values Removed Values Added
First Time appeared Redhat
Redhat enterprise Linux
CPEs cpe:/a:redhat:enterprise_linux:8::nfv
cpe:/o:redhat:enterprise_linux:8
Vendors & Products Redhat
Redhat enterprise Linux

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-05-04T09:07:46.833Z

Reserved: 2024-05-17T13:50:33.113Z

Link: CVE-2024-35893

cve-icon Vulnrichment

Updated: 2024-08-02T03:21:48.968Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2024-05-19T09:15:10.307

Modified: 2024-11-21T09:21:08.660

Link: CVE-2024-35893

cve-icon Redhat

Severity : Low

Publid Date: 2024-05-19T00:00:00Z

Links: CVE-2024-35893 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.