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---
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-3840-1 | linux security update |
Debian DLA |
DLA-3842-1 | linux-5.10 security update |
Ubuntu USN |
USN-6893-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6893-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6893-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6896-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6896-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6896-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6896-4 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6896-5 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6898-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6898-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6898-3 | Linux kernel kernel vulnerabilities |
Ubuntu USN |
USN-6898-4 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6917-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6918-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6919-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6927-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7019-1 | Linux kernel vulnerabilities |
Tue, 12 May 2026 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Tue, 23 Dec 2025 19:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Debian
Debian debian Linux Linux Linux linux Kernel |
|
| Weaknesses | CWE-908 | |
| CPEs | cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc2:*:*:*:*:*:* |
|
| Vendors & Products |
Debian
Debian debian Linux Linux Linux linux Kernel |
Fri, 11 Jul 2025 13:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
epss
|
epss
|
Fri, 22 Nov 2024 12:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Tue, 05 Nov 2024 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
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 |
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-12T11:52:28.473Z
Reserved: 2024-05-17T13:50:33.113Z
Link: CVE-2024-35893
Updated: 2024-08-02T03:21:48.968Z
Status : Modified
Published: 2024-05-19T09:15:10.307
Modified: 2026-05-12T12:16:39.097
Link: CVE-2024-35893
OpenCVE Enrichment
No data.
Debian DLA
Ubuntu USN