[Bug c++/104161] New: Potential Security Vulnerability: remove_all and symbolic link

[adrien.devresse at metamorphe dot engineering]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104161

            Bug ID: 104161
           Summary: Potential Security Vulnerability: remove_all and
                    symbolic link
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: adrien.devresse at metamorphe dot engineering
  Target Milestone: ---

Dear all,

The Rust compiler recently reported a CVE about a vulnerability about the
recursive deletion on the filesystem and the use of symlink.

https://blog.rust-lang.org/2022/01/20/cve-2022-21658.html


Ater a quick check, I do believe the implementation of
std::filesystem::remove_all presents the same vulnerability

https://en.cppreference.com/w/cpp/filesystem/remove

The logic rely on directory_iterator NOT opening symbolic link liked mandated
by the standard

https://en.cppreference.com/w/cpp/filesystem/directory_iterator


https://github.com/playbar/cpplearn/blob/master/gcc/libstdc%2B%2B-v3/src/c%2B%2B17/fs_ops.cc#L1300

However, it seems GCC implementation of directory_iterator does open and follow
symbolic links when used on it

https://godbolt.org/#z:OYLghAFBqd5QCxAYwPYBMCmBRdBLAF1QCcAaPECAMzwBtMA7AQwFtMQByARg9KtQYEAysib0QXACx8BBAKoBnTAAUAHpwAMvAFYTStJg1DIApACYAQuYukl9ZATwDKjdAGFUtAK4sGIM9KuADJ4DJgAcj4ARpjE/tIADqgKhE4MHt6%2B8aRJKY4CIWGRLDFxAbaY9vkMQgRMxAQZPn7ldpgOabX1BIUR0bHZCnUNTVmtwz2hfSUDAQCUtqhexMjsHOYAzKHI3lgA1CYbbk5DxJish9gmGgCCm9u7mAdHNPQKAJ5DmCyX13dmWwYOy8%2B0Obi8DDwQ3QADoEL9bn9QgQ9iwmKEIMi9vVgMhSHtkAh6gAqYnY4jAABucxMAHYrLc9kyCQIhgSicQ9mSFLRQgBrZ4AEQOZjMAHoCCwEhLMENzGZDhYDoiVTdmXsxWKCWcmAQnh8WLyGHy/uq8FQIHsDUa%2BRB5WLMARTKL8Tz%2BXMmWAwIdhRoafTTermdCQChYpywWCRWY9lR0bRtedHEYre9DfyDgBWNwMeWKwNBvaYVSECBcGkbBlq5l0wV/euM5mavZ6tmEU3XACcIZA4ZIAH00Pt2oqayrO0wvEQ9oQhVaCOhQ69ZZ89SxQ/gzg4SO9%2B4RYrqSBA3cb8e0K1WC/PFyglijI0dozF%2BGc9ryhqFgCZs7nRfnxy%2BECTtO5gAGyxnsIAzgQ/qXhonZdj2aBTs8bhRlQqFRvK0aYY%2BeY/nmlYNghtJ1o2TJIXeuFuNGTBUHqnLvsmX4EX%2BRGIqRfwcAstCcJmvB%2BBwWikKgnBoZY1hWksKxPJsPCkAQmjcQsfIgBsGwwupWnaTpoH6JwkgCUpImcLwCggBoClKQscCwEgaBSnQsTkJQDkJE5cTAFwXBmHwdAMeZEBRMZUShPU7ycPJDlsIIADyDC0BFQm8FgaJGOIyWkJu7SOJSsrGcW7RTmswnIpUxm8lExDhR4WDGQQxB4Ou3DcXwBjAAoABqeCYAA7rFCSMJFvD8IIIhiOwUgyIIigqOomW6Fw%2BiGMY1jWPoeBROZkALKgCTVOZHAALTQj6zpWJYXC0mZlQ5WkLgMO4njNHowRTMUpR6LkqQCKMfhLd91S9B9AxLW0HQCF0IzPVkYO3RDNQTMD/RxGDEx/XoQzdMjMyowsCjSasegNZgaw8DxfFGZlokcKoAAcoFHaBkh7LiyB7N5MIxhA4kXTYey4IQJAihsS17B4jn0BGALlrwinJXMKlqRpOmq1pem8RwhmkIJwk02ZFlWQrpC2YgIB3gkU4uRAbkea9%2BBEKj03CKI4hTaN8hKGo9VnGTvC9dVCTDRTHD8Trxk07FU6WyiqAYfTjPM6zyDs5z3MS%2B5Usi7LRtaIrpCqepmlq6r%2Bla1TeumbYhvy3nIdmBXvD67nymkHlxApM4khAA


Consequently, GCC seems logicially vulnerable to this attack.

Regards,

A.D