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gitattributes parsing integer overflow

Critical
ttaylorr published GHSA-c738-c5qq-xg89 Jan 17, 2023

Package

No package listed

Affected versions

<= v2.30.6, v2.31.5, v2.32.4, v2.33.5, v2.34.5, v2.35.5, v2.36.3, v2.37.4, v2.38.2, v2.39.0

Patched versions

>= v2.30.7, v2.31.6, v2.32.5, v2.33.6, v2.34.6, v2.35.6, v2.36.4, v2.37.5, v2.38.3, v2.39.1

Description

Impact

gitattributes are a mechanism to allow defining attributes for paths. These attributes can be defined by adding a .gitattributes file to the repository, which contains a set of file patterns and the attributes that should be set for paths matching this pattern.

When parsing gitattributes, multiple integer overflows can occur when there is a huge number of path patterns, a huge number of attributes for a single pattern, or when the declared attribute names are huge.

These overflows can be triggered via a crafted .gitattributes file that may be part of the commit history. Git silently splits lines longer than 2KB when parsing gitattributes from a file, but not when parsing them from the index. Consequentially, the failure mode depends on whether the file exists in the working tree, the index or both.

This integer overflow can result in arbitrary heap reads and writes, which may result in remote code execution.

Patches

The problem has been patched in the versions published on 2023-01-17, going back to v2.30.7

Workarounds

The most complete workaround is upgrading to the most recent patched version published.

Credit

Credit forfinding this vulnerability goes to Markus Vervier and Eric Sesterhenn of X41 D-Sec. This work was sponsored by OSTIF. Fixes were written by Patrick Steinhardt of GitLab with help from others on the Git security mailing list.

Severity

Critical

CVE ID

CVE-2022-23521

Weaknesses