Fix for CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

[asadeddin]

Corgea is an AI security engineer that fixes vulnerable code.

It issued this PR to fix a vulnerability for you to review.

See the issue and fix in Corgea.

Explanation of the issue

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Many file operations are intended to take place within a restricted directory. By using special elements such as ".." and "/" separators, attackers can escape outside of the restricted location to access files or directories that are elsewhere on the system. One of the most common special elements is the "../" sequence, which in most modern operating systems is interpreted as the parent directory of the current location. This is referred to as relative path traversal. Path traversal also covers the use of absolute pathnames such as "/usr/local/bin", which may also be useful in accessing unexpected files. This is referred to as absolute path traversal.
In many programming languages, the injection of a null byte (the 0 or NUL) may allow an attacker to truncate a generated filename to widen the scope of attack. For example, the product may add ".txt" to any pathname, thus limiting the attacker to text files, but a null injection may effectively remove this restriction.

Explanation of the fix

The fix addresses a Path Traversal vulnerability by normalizing and resolving the path to the ClickHouse CA file, ensuring it stays within the restricted directory.

• The fix uses path.normalize() to neutralize special elements like ".." and "/" in the pathname, preventing the path from resolving to a location outside the restricted directory.
• It also uses path.resolve() to convert the normalized path into an absolute path. This ensures that the path always points to the intended file, even if the path is relative.
• The fix uses a regular expression to replace any sequence of ".." followed by "/" or "" or at the end of the string, further ensuring that the path stays within the restricted directory.
• The use of fs.readFileSync() remains the same, it reads the file at the resolved and normalized path.
• This fix doesn't address null byte injection as it's not a common issue in JavaScript or TypeScript, but it's something to be aware of in other languages.

[PratikPramanik]

This one seems fine

[PratikPramanik]

approving for my own records