CVE-2022-48987: media: v4l2-dv-timings.c: fix too strict blanking sanity checks

Vulnerability summary

CVE-2022-48987 is a medium (CVSS 5.5) Integer Overflow or Wraparound 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. 21-10-2024
   PublishedVulnerability first disclosed.
2. 11-05-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: media: v4l2-dv-timings.c: fix too strict blanking sanity checks Sanity checks were added to verify the v4l2_bt_timings blanking fields in order to avoid integer overflows when userspace passes weird values. But that assumed that userspace would correctly fill in the front porch, backporch and sync values, but sometimes all you know is the total blanking, which is then assigned to just one of these fields. And that can fail with these checks. So instead set a maximum for the total horizontal and vertical blanking and check that each field remains below that. That is still sufficient to avoid integer overflows, but it also allows for more flexibility in how userspace fills in these fields.

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.