CVE-2024-50126: net: sched: use RCU read-side critical section in taprio_dump()
First published: Tue Nov 05 2024(Updated: )
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+0x88/0x2e0 [T15862] el0_svc_common.constprop.0+0xe4/0x2a0 [T15862] do_el0_svc+0x44/0x60 [T15862] el0_svc+0x50/0x184 [T15862] el0t_64_sync_handler+0x120/0x12c [T15862] el0t_64_sync+0x190/0x194 [T15862] [T15862] Allocated by task 15857: [T15862] kasan_save_stack+0x3c/0x70 [T15862] kasan_save_track+0x20/0x3c [T15862] kasan_save_alloc_info+0x40/0x60 [T15862] __kasan_kmalloc+0xd4/0xe0 [T15862] __kmalloc_cache_noprof+0x194/0x334 [T15862] taprio_change+0x45c/0x2fe0 [T15862] tc_modify_qdisc+0x6a8/0x1838 [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+0x88/0x2e0 [T15862] el0_svc_common.constprop.0+0xe4/0x2a0 [T15862] do_el0_svc+0x44/0x60 [T15862] el0_svc+0x50/0x184 [T15862] el0t_64_sync_handler+0x120/0x12c [T15862] el0t_64_sync+0x190/0x194 [T15862] [T15862] Freed by task 6192: [T15862] kasan_save_stack+0x3c/0x70 [T15862] kasan_save_track+0x20/0x3c [T15862] kasan_save_free_info+0x4c/0x80 [T15862] poison_slab_object+0x110/0x160 [T15862] __kasan_slab_free+0x3c/0x74 [T15862] kfree+0x134/0x3c0 [T15862] taprio_free_sched_cb+0x18c/0x220 [T15862] rcu_core+0x920/0x1b7c [T15862] rcu_core_si+0x10/0x1c [T15862] handle_softirqs+0x2e8/0xd64 [T15862] __do_softirq+0x14/0x20
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | >=6.1<6.6.59 | |
| Linux Kernel | >=6.7<6.11.6 | |
| Linux Kernel | =6.12-rc1 | |
| Linux Kernel | =6.12-rc2 | |
| Linux Kernel | =6.12-rc3 | |
| Linux Kernel | =6.12-rc4 | |
| debian/linux | 5.10.223-1 5.10.234-1 6.1.129-1 6.1.128-1 6.12.21-1 | |
| debian/linux-6.1 | 6.1.129-1~deb11u1 |
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Reference Links
- 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
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-50126
- https://nvd.nist.gov/vuln/detail/CVE-2024-50126
- https://launchpad.net/bugs/cve/CVE-2024-50126
- https://security-tracker.debian.org/tracker/CVE-2024-50126
- https://ubuntu.com/security/CVE-2024-50126
- https://git.kernel.org/linus/b22db8b8befe90b61c98626ca1a2fbb0505e9fe3
Frequently Asked Questions
What is the severity of CVE-2024-50126?
CVE-2024-50126 is considered to have a moderate severity due to the possibility of a use-after-free condition.
How do I fix CVE-2024-50126?
To fix CVE-2024-50126, update the Linux kernel to the latest stable version that includes the patch.
Which versions of the Linux kernel are affected by CVE-2024-50126?
CVE-2024-50126 affects Linux kernel versions from 6.1 to 6.6.59 and specific release candidates from 6.12.
Is CVE-2024-50126 exploitable on all architectures?
CVE-2024-50126 has not been seen on x86 but has been found on KASAN-enabled arm64 systems.
What components of the Linux kernel are impacted by CVE-2024-50126?
CVE-2024-50126 impacts the networking component, specifically the scheduling functionality in taprio_dump().
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