Описание
In the Linux kernel, the following vulnerability has been resolved:
l2tp: Fix memleak in l2tp_udp_encap_recv().
syzbot reported memleak of struct l2tp_session, l2tp_tunnel,
sock, etc. [0]
The cited commit moved down the validation of the protocol
version in l2tp_udp_encap_recv().
The new place requires an extra error handling to avoid the
memleak.
Let's call l2tp_session_put() there.
[0]:
BUG: memory leak
unreferenced object 0xffff88810a290200 (size 512):
comm "syz.0.17", pid 6086, jiffies 4294944299
hex dump (first 32 bytes):
7d eb 04 0c 00 00 00 00 01 00 00 00 00 00 00 00 }...............
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc babb6a4f):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4958 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_noprof+0x3e0/0x660 mm/slub.c:5669
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
l2tp_session_create+0x3a/0x3b0 net/l2tp/l2tp_core.c:1778
pppol2tp_connect+0x48b/0x920 net/l2tp/l2tp_ppp.c:755
__sys_connect_file+0x7a/0xb0 net/socket.c:2089
__sys_connect+0xde/0x110 net/socket.c:2108
__do_sys_connect net/socket.c:2114 [inline]
__se_sys_connect net/socket.c:2111 [inline]
__x64_sys_connect+0x1c/0x30 net/socket.c:2111
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
A memory leak vulnerability was found in the Linux kernel's L2TP (Layer 2 Tunneling Protocol) implementation. After a code refactoring that moved protocol version validation in l2tp_udp_encap_recv(), the error handling path fails to call l2tp_session_put() to release the session reference. This causes l2tp_session, l2tp_tunnel, and associated socket structures to leak on each failed validation.
Отчет
This memory leak was discovered by syzkaller and affects systems using L2TP tunneling. Repeated triggering of the error path through malformed L2TP packets can gradually exhaust kernel memory, leading to denial of service. The leak requires the ability to send L2TP traffic to the affected system.
Меры по смягчению последствий
To mitigate this issue, prevent the l2tp_core module from being loaded if L2TP tunneling is not required. See https://access.redhat.com/solutions/41278 for instructions on how to blacklist a kernel module.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Affected | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected |
Показывать по
Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: l2tp: Fix memleak in l2tp_udp_encap_recv(). syzbot reported memleak of struct l2tp_session, l2tp_tunnel, sock, etc. [0] The cited commit moved down the validation of the protocol version in l2tp_udp_encap_recv(). The new place requires an extra error handling to avoid the memleak. Let's call l2tp_session_put() there. [0]: BUG: memory leak unreferenced object 0xffff88810a290200 (size 512): comm "syz.0.17", pid 6086, jiffies 4294944299 hex dump (first 32 bytes): 7d eb 04 0c 00 00 00 00 01 00 00 00 00 00 00 00 }............... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc babb6a4f): kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline] slab_post_alloc_hook mm/slub.c:4958 [inline] slab_alloc_node mm/slub.c:5263 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_noprof+0x3e0/0x660 mm/slub.c:5669 kmalloc_noprof include/linux/slab.h:961 [inline] kzalloc_noprof include/l...
In the Linux kernel, the following vulnerability has been resolved: l2tp: Fix memleak in l2tp_udp_encap_recv(). syzbot reported memleak of struct l2tp_session, l2tp_tunnel, sock, etc. [0] The cited commit moved down the validation of the protocol version in l2tp_udp_encap_recv(). The new place requires an extra error handling to avoid the memleak. Let's call l2tp_session_put() there. [0]: BUG: memory leak unreferenced object 0xffff88810a290200 (size 512): comm "syz.0.17", pid 6086, jiffies 4294944299 hex dump (first 32 bytes): 7d eb 04 0c 00 00 00 00 01 00 00 00 00 00 00 00 }............... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc babb6a4f): kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline] slab_post_alloc_hook mm/slub.c:4958 [inline] slab_alloc_node mm/slub.c:5263 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_noprof+0x3e0/0x660 mm/slub.c:5669 kmalloc_noprof include/linux/sla
In the Linux kernel, the following vulnerability has been resolved: l ...
In the Linux kernel, the following vulnerability has been resolved: l2tp: Fix memleak in l2tp_udp_encap_recv(). syzbot reported memleak of struct l2tp_session, l2tp_tunnel, sock, etc. [0] The cited commit moved down the validation of the protocol version in l2tp_udp_encap_recv(). The new place requires an extra error handling to avoid the memleak. Let's call l2tp_session_put() there. [0]: BUG: memory leak unreferenced object 0xffff88810a290200 (size 512): comm "syz.0.17", pid 6086, jiffies 4294944299 hex dump (first 32 bytes): 7d eb 04 0c 00 00 00 00 01 00 00 00 00 00 00 00 }............... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc babb6a4f): kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline] slab_post_alloc_hook mm/slub.c:4958 [inline] slab_alloc_node mm/slub.c:5263 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_noprof+0x3e0/0x660 mm/slub.c:5669 kmalloc_noprof include/linux/...
EPSS
5.5 Medium
CVSS3