In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix racing between bpf_timer_cancel_and_free and bpf_timer_cancel
The following race is possible between bpf_timer_cancel_and_free
and bpf_timer_cancel. It will lead a UAF on the timer->timer.
bpf_timer_cancel();
spin_lock();
t = timer->time;
spin_unlock();
bpf_timer_cancel_and_free();
spin_lock();
t = timer->timer;
timer->timer = NULL;
spin_unlock();
hrtimer_cancel(&t->timer);
kfree(t);
/* UAF on t */
hrtimer_cancel(&t->timer);
In bpf_timer_cancel_and_free, this patch frees the timer->timer
after a rcu grace period. This requires a rcu_head addition
to the "struct bpf_hrtimer". Another kfree(t) happens in bpf_timer_init,
this does not need a kfree_rcu because it is still under the
spin_lock and timer->timer has not been visible by others yet.
In bpf_timer_cancel, rcu_read_lock() is added because this helper
can be used in a non rcu critical section context (e.g. from
a sleepable bpf prog). Other timer->timer usages in helpers.c
have been audited, bpf_timer_cancel() is the only place where
timer->timer is used outside of the spin_lock.
Another solution considered is to mark a t->flag in bpf_timer_cancel
and clear it after hrtimer_cancel() is done. In bpf_timer_cancel_and_free,
it busy waits for the flag to be cleared before kfree(t). This patch
goes with a straight forward solution and frees timer->timer after
a rcu grace period.
References
Configurations
Configuration 1 (hide)
|
History
04 Apr 2025, 14:34
| Type | Values Removed | Values Added |
|---|---|---|
| CWE | CWE-416 | |
| First Time |
Linux linux Kernel
Linux |
|
| References | () https://git.kernel.org/stable/c/0281b919e175bb9c3128bd3872ac2903e9436e3f - Patch | |
| References | () https://git.kernel.org/stable/c/5268bb02107b9eedfdcd51db75b407d10043368c - Patch | |
| References | () https://git.kernel.org/stable/c/7d80a9e745fa5b47da3bca001f186c02485c7c33 - Patch | |
| References | () https://git.kernel.org/stable/c/8327ed12e8ebc5436bfaa1786c49988894f9c8a6 - Patch | |
| References | () https://git.kernel.org/stable/c/addf5e297e6cbf5341f9c07720693ca9ba0057b5 - Patch | |
| CPE | cpe:2.3:o:linux:linux_kernel:6.8:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc2:*:*:*:*:*:* |
21 Nov 2024, 09:02
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://git.kernel.org/stable/c/0281b919e175bb9c3128bd3872ac2903e9436e3f - | |
| References | () https://git.kernel.org/stable/c/5268bb02107b9eedfdcd51db75b407d10043368c - | |
| References | () https://git.kernel.org/stable/c/7d80a9e745fa5b47da3bca001f186c02485c7c33 - | |
| References | () https://git.kernel.org/stable/c/8327ed12e8ebc5436bfaa1786c49988894f9c8a6 - | |
| References | () https://git.kernel.org/stable/c/addf5e297e6cbf5341f9c07720693ca9ba0057b5 - |
04 Nov 2024, 19:35
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
03 Apr 2024, 17:24
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2024-04-03 17:15
Updated : 2025-04-04 14:34
NVD link : CVE-2024-26737
Mitre link : CVE-2024-26737
CVE.ORG link : CVE-2024-26737
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-416
Use After Free