CVE-2024-35860 Affecting kernel-source-azure package, versions <5.14.21-150500.33.57.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-SLES155-KERNELSOURCEAZURE-7254469
- published14 Jun 2024
- disclosed13 Jun 2024
Introduced: 13 Jun 2024
CVE-2024-35860 (opens in a new tab)How to fix?
Upgrade SLES:15.5 kernel-source-azure to version 5.14.21-150500.33.57.1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-source-azure package and not the kernel-source-azure package as distributed by SLES.
See How to fix? for SLES:15.5 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
bpf: support deferring bpf_link dealloc to after RCU grace period
BPF link for some program types is passed as a "context" which can be used by those BPF programs to look up additional information. E.g., for multi-kprobes and multi-uprobes, link is used to fetch BPF cookie values.
Because of this runtime dependency, when bpf_link refcnt drops to zero there could still be active BPF programs running accessing link data.
This patch adds generic support to defer bpf_link dealloc callback to after RCU GP, if requested. This is done by exposing two different deallocation callbacks, one synchronous and one deferred. If deferred one is provided, bpf_link_free() will schedule dealloc_deferred() callback to happen after RCU GP.
BPF is using two flavors of RCU: "classic" non-sleepable one and RCU tasks trace one. The latter is used when sleepable BPF programs are used. bpf_link_free() accommodates that by checking underlying BPF program's sleepable flag, and goes either through normal RCU GP only for non-sleepable, or through RCU tasks trace GP and then normal RCU GP (taking into account rcu_trace_implies_rcu_gp() optimization), if BPF program is sleepable.
We use this for multi-kprobe and multi-uprobe links, which dereference link during program run. We also preventively switch raw_tp link to use deferred dealloc callback, as upcoming changes in bpf-next tree expose raw_tp link data (specifically, cookie value) to BPF program at runtime as well.
References
- https://www.suse.com/security/cve/CVE-2024-35860.html
- https://bugzilla.suse.com/1224531
- https://git.kernel.org/stable/c/1a80dbcb2dbaf6e4c216e62e30fa7d3daa8001ce
- https://git.kernel.org/stable/c/5d8d447777564b35f67000e7838e7ccb64d525c8
- https://git.kernel.org/stable/c/876941f533e7b47fc69977fc4551c02f2d18af97