CVE-2023-53368
What it is
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix race issue between cpu buffer write and swap Warning happened in rb_end_commit() at code: if (RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))) WARNING: CPU: 0 PID: 139 at kernel/trace/ring_buffer.c:3142 rb_commit+0x402/0x4a0 Call Trace: ring_buffer_unlock_commit+0x42/0x250 trace_buffer_unlock_commit_regs+0x3b/0x250 trace_event_buffer_commit+0xe5/0x440 trace_event_buffer_reserve+0x11c/0x150 trace_event_raw_event_sched_switch+0x23c/0x2c0 __traceiter_sched_switch+0x59/0x80 __schedule+0x72b/0x1580 schedule+0x92/0x120 worker_thread+0xa0/0x6f0 It is because the race between writing event into cpu buffer and swapping cpu buffer through file per_cpu/cpu0/snapshot: Write on CPU 0 Swap buffer by per_cpu/cpu0/snapshot on CPU 1 -------- -------- tracing_snapshot_write() [...] ring_buffer_lock_reserve() cpu_buffer = buffer->buffers[cpu]; // 1. Suppose find 'cpu_buffer_a'; [...] rb_reserve_next_event() [...] ring_buffer_swap_cpu() if (local_read(&cpu_buffer_a->committing)) goto out_dec; if (local_read(&cpu_buffer_b->committing)) goto out_dec; buffer_a->buffers[cpu] = cpu_buffer_b; buffer_b->buffers[cpu] = cpu_buffer_a; // 2. cpu_buffer has swapped here. rb_start_commit(cpu_buffer); if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) { // 3. This check passed due to 'cpu_buffer->buffer' [...] // has not changed here. return NULL; } cpu_buffer_b->buffer = buffer_a; cpu_buffer_a->buffer = buffer_b; [...] // 4. Reserve event from 'cpu_buffer_a'. ring_buffer_unlock_commit() [...] cpu_buffer = buffer->buffers[cpu]; // 5. Now find 'cpu_buffer_b' !!! rb_commit(cpu_buffer) rb_end_commit() // 6. WARN for the wrong 'committing' state !!! Based on above analysis, we can easily reproduce by following testcase: ``` bash #!/bin/bash dmesg -n 7 sysctl -w kernel.panic_on_warn=1 TR=/sys/kernel/tracing echo 7 > ${TR}/buffer_size_kb echo "sched:sched_switch" > ${TR}/set_event while [ true ]; do echo 1 > ${TR}/per_cpu/cpu0/snapshot done & while [ true ]; do echo 1 > ${TR}/per_cpu/cpu0/snapshot done & while [ true ]; do echo 1 > ${TR}/per_cpu/cpu0/snapshot done & ``` To fix it, IIUC, we can use smp_call_function_single() to do the swap on the target cpu where the buffer is located, so that above race would be avoided.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.
- Exploit odds
- 0.1% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.1% in the next 30 days (EPSS).
- Severity: 4.7 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.1% · EPSS, next 30 days
- Weakness
- CWE-362 · Race condition
- Record status
- Modified
Affected
- Linux Kernel < 5.4.257
- Linux Kernel < 5.10.195
- Linux Kernel < 5.15.132
- Linux Kernel < 6.1.53
- Linux Kernel < 6.4.16
- Linux Kernel < 6.5.3
Attack profile CVSS 3.1 · 4.7
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2023-53368.md and follow it. Check whether this project is affected by CVE-2023-53368. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/3163f635b20e9e1fb4659e74f47918c9dddfe64e
- https://git.kernel.org/stable/c/37ca1b686078b00cc4ffa008e2190615f7709b5d
- https://git.kernel.org/stable/c/6182318ac04648b46db9d441fd7d696337fcdd0b
- https://git.kernel.org/stable/c/74c85396bd73eca80b96510b4edf93b9a3aff75f
- https://git.kernel.org/stable/c/89c89da92a60028013f9539be0dcce7e44405a43
- https://git.kernel.org/stable/c/90e037cabc2c2dfc39b3dd9c5b22ea91f995539a
- https://git.kernel.org/stable/c/c5d30d6aa83d99fba8dfdd9cf6c4e4e7a63244db
References
- https://git.kernel.org/stable/c/3163f635b20e9e1fb4659e74f47918c9dddfe64e
- https://git.kernel.org/stable/c/37ca1b686078b00cc4ffa008e2190615f7709b5d
- https://git.kernel.org/stable/c/6182318ac04648b46db9d441fd7d696337fcdd0b
- https://git.kernel.org/stable/c/74c85396bd73eca80b96510b4edf93b9a3aff75f
- https://git.kernel.org/stable/c/89c89da92a60028013f9539be0dcce7e44405a43
- https://git.kernel.org/stable/c/90e037cabc2c2dfc39b3dd9c5b22ea91f995539a
- https://git.kernel.org/stable/c/c5d30d6aa83d99fba8dfdd9cf6c4e4e7a63244db