CVE-2023-52501: ring-buffer: Do not attempt to read past "commit"

Vulnerability summary

CVE-2023-52501 is a high (CVSS 7.1) Out-of-bounds Read vulnerability in linux. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 16.2% of scored vulnerabilities.

Timeline

1. 02-03-2024
   PublishedVulnerability first disclosed.
2. 11-05-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Do not attempt to read past "commit" When iterating over the ring buffer while the ring buffer is active, the writer can corrupt the reader. There's barriers to help detect this and handle it, but that code missed the case where the last event was at the very end of the page and has only 4 bytes left. The checks to detect the corruption by the writer to reads needs to see the length of the event. If the length in the first 4 bytes is zero then the length is stored in the second 4 bytes. But if the writer is in the process of updating that code, there's a small window where the length in the first 4 bytes could be zero even though the length is only 4 bytes. That will cause rb_event_length() to read the next 4 bytes which could happen to be off the allocated page. To protect against this, fail immediately if the next event pointer is less than 8 bytes from the end of the commit (last byte of data), as all events must be a minimum of 8 bytes anyway.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.