In the Linux kernel, the following vulnerability has been resolved:
net: sched: fix memory leak in tcindex_set_parms
Syzkaller reports a memory leak as follows:
====================================
BUG: memory leak
unreferenced object 0xffff88810c287f00 (size 256):
comm "syz-executor105", pid 3600, jiffies 4294943292 (age 12.990s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff814cf9f0>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
[<ffffffff839c9e07>] kmalloc include/linux/slab.h:576 [inline]
[<ffffffff839c9e07>] kmalloc_array include/linux/slab.h:627 [inline]
[<ffffffff839c9e07>] kcalloc include/linux/slab.h:659 [inline]
[<ffffffff839c9e07>] tcf_exts_init include/net/pkt_cls.h:250 [inline]
[<ffffffff839c9e07>] tcindex_set_parms+0xa7/0xbe0 net/sched/cls_tcindex.c:342
[<ffffffff839caa1f>] tcindex_change+0xdf/0x120 net/sched/cls_tcindex.c:553
[<ffffffff8394db62>] tc_new_tfilter+0x4f2/0x1100 net/sched/cls_api.c:2147
[<ffffffff8389e91c>] rtnetlink_rcv_msg+0x4dc/0x5d0 net/core/rtnetlink.c:6082
[<ffffffff839eba67>] netlink_rcv_skb+0x87/0x1d0 net/netlink/af_netlink.c:2540
[<ffffffff839eab87>] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
[<ffffffff839eab87>] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345
[<ffffffff839eb046>] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921
[<ffffffff8383e796>] sock_sendmsg_nosec net/socket.c:714 [inline]
[<ffffffff8383e796>] sock_sendmsg+0x56/0x80 net/socket.c:734
[<ffffffff8383eb08>] ____sys_sendmsg+0x178/0x410 net/socket.c:2482
[<ffffffff83843678>] ___sys_sendmsg+0xa8/0x110 net/socket.c:2536
[<ffffffff838439c5>] __sys_sendmmsg+0x105/0x330 net/socket.c:2622
[<ffffffff83843c14>] __do_sys_sendmmsg net/socket.c:2651 [inline]
[<ffffffff83843c14>] __se_sys_sendmmsg net/socket.c:2648 [inline]
[<ffffffff83843c14>] __x64_sys_sendmmsg+0x24/0x30 net/socket.c:2648
[<ffffffff84605fd5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84605fd5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
====================================
Kernel uses tcindex_change() to change an existing
filter properties.
Yet the problem is that, during the process of changing,
if `old_r` is retrieved from `p->perfect`, then
kernel uses tcindex_alloc_perfect_hash() to newly
allocate filter results, uses tcindex_filter_result_init()
to clear the old filter result, without destroying
its tcf_exts structure, which triggers the above memory leak.
To be more specific, there are only two source for the `old_r`,
according to the tcindex_lookup(). `old_r` is retrieved from
`p->perfect`, or `old_r` is retrieved from `p->h`.
* If `old_r` is retrieved from `p->perfect`, kernel uses
tcindex_alloc_perfect_hash() to newly allocate the
filter results. Then `r` is assigned with `cp->perfect + handle`,
which is newly allocated. So condition `old_r && old_r != r` is
true in this situation, and kernel uses tcindex_filter_result_init()
to clear the old filter result, without destroying
its tcf_exts structure
* If `old_r` is retrieved from `p->h`, then `p->perfect` is NULL
according to the tcindex_lookup(). Considering that `cp->h`
is directly copied from `p->h` and `p->perfect` is NULL,
`r` is assigned with `tcindex_lookup(cp, handle)`, whose value
should be the same as `old_r`, so condition `old_r && old_r != r`
is false in this situation, kernel ignores using
tcindex_filter_result_init() to clear the old filter result.
So only when `old_r` is retrieved from `p->perfect` does kernel use
tcindex_filter_result_init() to clear the old filter result, which
triggers the above memory leak.
Considering that there already exists a tc_filter_wq workqueue
to destroy the old tcindex_d
---truncated---
References
Configurations
Configuration 1 (hide)
|
History
11 Dec 2025, 20:00
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://git.kernel.org/stable/c/01d0d2b8b4e3cf2110baba9371c0c3d04ad5c77b - Patch | |
| References | () https://git.kernel.org/stable/c/18c3fa7a7fdbb4d21dafc8a7710ae2c1680930f6 - Patch | |
| References | () https://git.kernel.org/stable/c/372ae77cf11d11fb118cbe2d37def9dd5f826abd - Patch | |
| References | () https://git.kernel.org/stable/c/399ab7fe0fa0d846881685fd4e57e9a8ef7559f7 - Patch | |
| References | () https://git.kernel.org/stable/c/3abebc503a5148072052c229c6b04b329a420ecd - Patch | |
| References | () https://git.kernel.org/stable/c/53af9c793f644d5841d84d8e0ad83bd7ab47f3e0 - Patch | |
| References | () https://git.kernel.org/stable/c/55ac68b53f1cea1926ee2313afc5d66b91daad71 - Patch | |
| References | () https://git.kernel.org/stable/c/6c55953e232ea668731091d111066521f3b7719b - Patch | |
| References | () https://git.kernel.org/stable/c/7a6fb69bbcb21e9ce13bdf18c008c268874f0480 - Patch | |
| References | () https://git.kernel.org/stable/c/7c183dc0af472dec33d2c0786a5e356baa8cad19 - Patch | |
| References | () https://git.kernel.org/stable/c/b314f6c3512108d7a656c5caf07c82d1bbbdc0f1 - Patch | |
| References | () https://git.kernel.org/stable/c/c4de6057e7c6654983acb63d939d26ac0d7bbf39 - Patch | |
| References | () https://git.kernel.org/stable/c/facc4405e8b7407e03216207b1d1d640127de0c8 - Patch | |
| First Time |
Linux
Linux linux Kernel |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| CWE | CWE-401 | |
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
29 Sep 2025, 12:15
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
18 Sep 2025, 14:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2025-09-18 14:15
Updated : 2026-01-14 19:16
NVD link : CVE-2022-50396
Mitre link : CVE-2022-50396
CVE.ORG link : CVE-2022-50396
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-401
Missing Release of Memory after Effective Lifetime