Description

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

net: sched: use RCU read-side critical section in taprio_dump()

Fix possible use-after-free in 'taprio_dump()' by adding RCU
read-side critical section there. Never seen on x86 but
found on a KASAN-enabled arm64 system when investigating
https://syzkaller.appspot.com/bug?extid=b65e0af58423fc8a73aa:

[T15862] BUG: KASAN: slab-use-after-free in taprio_dump+0xa0c/0xbb0
[T15862] Read of size 4 at addr ffff0000d4bb88f8 by task repro/15862
[T15862]
[T15862] CPU: 0 UID: 0 PID: 15862 Comm: repro Not tainted 6.11.0-rc1-00293-gdefaf1a2113a-dirty #2
[T15862] Hardware name: QEMU QEMU Virtual Machine, BIOS edk2-20240524-5.fc40 05/24/2024
[T15862] Call trace:
[T15862] dump_backtrace+0x20c/0x220
[T15862] show_stack+0x2c/0x40
[T15862] dump_stack_lvl+0xf8/0x174
[T15862] print_report+0x170/0x4d8
[T15862] kasan_report+0xb8/0x1d4
[T15862] __asan_report_load4_noabort+0x20/0x2c
[T15862] taprio_dump+0xa0c/0xbb0
[T15862] tc_fill_qdisc+0x540/0x1020
[T15862] qdisc_notify.isra.0+0x330/0x3a0
[T15862] tc_modify_qdisc+0x7b8/0x1838
[T15862] rtnetlink_rcv_msg+0x3c8/0xc20
[T15862] netlink_rcv_skb+0x1f8/0x3d4
[T15862] rtnetlink_rcv+0x28/0x40
[T15862] netlink_unicast+0x51c/0x790
[T15862] netlink_sendmsg+0x79c/0xc20
[T15862] __sock_sendmsg+0xe0/0x1a0
[T15862] ____sys_sendmsg+0x6c0/0x840
[T15862] ___sys_sendmsg+0x1ac/0x1f0
[T15862] __sys_sendmsg+0x110/0x1d0
[T15862] __arm64_sys_sendmsg+0x74/0xb0
[T15862] invoke_syscall+...

Classification

CVE ID: CVE-2024-50126

CVSS Base Severity: LOW

CVSS Base Score: 0.0

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 5.08% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/b911fa9e92ee586e36479ad57b88f20471acaca1
https://git.kernel.org/stable/c/5d282467245f267c0b9ada3f7f309ff838521536
https://git.kernel.org/stable/c/e4369cb6acf6b895ac2453cc1cdf2f4326122c6d
https://git.kernel.org/stable/c/b22db8b8befe90b61c98626ca1a2fbb0505e9fe3

Timeline