Bug 2334548 (CVE-2024-56675)

Summary:	CVE-2024-56675 kernel: bpf: Fix UAF via mismatching bpf_prog/attachment RCU flavors
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	dfreiber, drow, jburrell, vkumar
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2024-12-27 16:02:48 UTC

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

bpf: Fix UAF via mismatching bpf_prog/attachment RCU flavors

Uprobes always use bpf_prog_run_array_uprobe() under tasks-trace-RCU
protection. But it is possible to attach a non-sleepable BPF program to a
uprobe, and non-sleepable BPF programs are freed via normal RCU (see
__bpf_prog_put_noref()). This leads to UAF of the bpf_prog because a normal
RCU grace period does not imply a tasks-trace-RCU grace period.

Fix it by explicitly waiting for a tasks-trace-RCU grace period after
removing the attachment of a bpf_prog to a perf_event.

Comment 1 Avinash Hanwate 2024-12-28 02:45:53 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024122756-CVE-2024-56675-e996@gregkh/T