Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Disable preemption in bpf_event_output We received report [1] of kernel crash, which is caused by using nesting protection without disabled preemption. The bpf_event_output can be called by programs executed by bpf_prog_run_array_cg function that disabled migration but keeps preemption enabled. This can cause task to be preempted by another one inside the nesting protection and lead eventually to two tasks using same perf_sample_data buffer and cause crashes like: BUG: kernel NULL pointer dereference, address: 0000000000000001 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page ... ? perf_output_sample+0x12a/0x9a0 ? finish_task_switch.isra.0+0x81/0x280 ? perf_event_output+0x66/0xa0 ? bpf_event_output+0x13a/0x190 ? bpf_event_output_data+0x22/0x40 ? bpf_prog_dfc84bbde731b257_cil_sock4_connect+0x40a/0xacb ? xa_load+0x87/0xe0 ? __cgroup_bpf_run_filter_sock_addr+0xc1/0x1a0 ? release_sock+0x3e/0x90 ? sk_setsockopt+0x1a1/0x12f0 ? udp_pre_connect+0x36/0x50 ? inet_dgram_connect+0x93/0xa0 ? __sys_connect+0xb4/0xe0 ? udp_setsockopt+0x27/0x40 ? __pfx_udp_push_pending_frames+0x10/0x10 ? __sys_setsockopt+0xdf/0x1a0 ? __x64_sys_connect+0xf/0x20 ? do_syscall_64+0x3a/0x90 ? entry_SYSCALL_64_after_hwframe+0x72/0xdc Fixing this by disabling preemption in bpf_event_output. [1] https://github.com/cilium/cilium/issues/26756
References
- https://git.kernel.org/stable/c/063c9ce8e74e07bf94f99cd13146f42867875e8b
- https://git.kernel.org/stable/c/3048cb0dc0cc9dc74ed93690dffef00733bcad5b
- https://git.kernel.org/stable/c/36dd8ca330b76585640ed32255a3c99f901e1502
- https://git.kernel.org/stable/c/c81bdf8f9f2b002d217c3d5357cdea9f2b82ff90
- https://git.kernel.org/stable/c/d62cc390c2e99ae267ffe4b8d7e2e08b6c758c32
FAQ
What is CVE-2023-54173?
CVE-2023-54173 is a documented vulnerability. In the Linux kernel, the following vulnerability has been resolved: bpf: Disable preemption in bpf_event_output We received report [1] of kernel crash, which is caused by using nesting protection wi...
How severe is CVE-2023-54173?
CVSS scoring is not yet available for CVE-2023-54173. Check NVD for updates.
Is there a patch for CVE-2023-54173?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.