git/fsck.c, branch v2.21.3

Git 2.21.3

2020-04-19T23:30:08Z

This merges up the security fix from v2.17.5. Signed-off-by: Jonathan Nieder

Git 2.20.4

2020-04-19T23:28:57Z

This merges up the security fix from v2.17.5. Signed-off-by: Jonathan Nieder

Git 2.19.5

2020-04-19T23:26:41Z

This merges up the security fix from v2.17.5. Signed-off-by: Jonathan Nieder

Git 2.18.4

2020-04-19T23:24:14Z

This merges up the security fix from v2.17.5. Signed-off-by: Jonathan Nieder

fsck: reject URL with empty host in .gitmodules

2020-04-19T23:10:58Z

Git's URL parser interprets https:///example.com/repo.git to have no host and a path of "example.com/repo.git". Curl, on the other hand, internally redirects it to https://example.com/repo.git. As a result, until "credential: parse URL without host as empty host, not unset", tricking a user into fetching from such a URL would cause Git to send credentials for another host to example.com. Teach fsck to block and detect .gitmodules files using such a URL to prevent sharing them with Git versions that are not yet protected. A relative URL in a .gitmodules file could also be used to trigger this. The relative URL resolver used for .gitmodules does not normalize sequences of slashes and can follow ".." components out of the path part and to the host part of a URL, meaning that such a relative URL can be used to traverse from a https://foo.example.com/innocent superproject to a https:///attacker.example.com/exploit submodule. Fortunately, redundant extra slashes in .gitmodules are rare, so we can catch this by detecting one after a leading sequence of "./" and "../" components. Helped-by: Jeff King Signed-off-by: Jonathan Nieder Reviewed-by: Jeff King

credential: treat URL without scheme as invalid

2020-04-19T23:10:58Z

libcurl permits making requests without a URL scheme specified. In this case, it guesses the URL from the hostname, so I can run git ls-remote http::ftp.example.com/path/to/repo and it would make an FTP request. Any user intentionally using such a URL is likely to have made a typo. Unfortunately, credential_from_url is not able to determine the host and protocol in order to determine appropriate credentials to send, and until "credential: refuse to operate when missing host or protocol", this resulted in another host's credentials being leaked to the named host. Teach credential_from_url_gently to consider such a URL to be invalid so that fsck can detect and block gitmodules files with such URLs, allowing server operators to avoid serving them to downstream users running older versions of Git. This also means that when such URLs are passed on the command line, Git will print a clearer error so affected users can switch to the simpler URL that explicitly specifies the host and protocol they intend. One subtlety: .gitmodules files can contain relative URLs, representing a URL relative to the URL they were cloned from. The relative URL resolver used for .gitmodules can follow ".." components out of the path part and past the host part of a URL, meaning that such a relative URL can be used to traverse from a https://foo.example.com/innocent superproject to a https::attacker.example.com/exploit submodule. Fortunately a leading ':' in the first path component after a series of leading './' and '../' components is unlikely to show up in other contexts, so we can catch this by detecting that pattern. Reported-by: Jeff King Signed-off-by: Jonathan Nieder Reviewed-by: Jeff King

fsck: convert gitmodules url to URL passed to curl

2020-04-19T23:10:58Z

In 07259e74ec1 (fsck: detect gitmodules URLs with embedded newlines, 2020-03-11), git fsck learned to check whether URLs in .gitmodules could be understood by the credential machinery when they are handled by git-remote-curl. However, the check is overbroad: it checks all URLs instead of only URLs that would be passed to git-remote-curl. In principle a git:// or file:/// URL does not need to follow the same conventions as an http:// URL; in particular, git:// and file:// protocols are not succeptible to issues in the credential API because they do not support attaching credentials. In the HTTP case, the URL in .gitmodules does not always match the URL that would be passed to git-remote-curl and the credential machinery: Git's URL syntax allows specifying a remote helper followed by a "::" delimiter and a URL to be passed to it, so that git ls-remote http::https://example.com/repo.git invokes git-remote-http with https://example.com/repo.git as its URL argument. With today's checks, that distinction does not make a difference, but for a check we are about to introduce (for empty URL schemes) it will matter. .gitmodules files also support relative URLs. To ensure coverage for the https based embedded-newline attack, urldecode and check them directly for embedded newlines. Helped-by: Jeff King Signed-off-by: Jonathan Nieder Reviewed-by: Jeff King

Git 2.21.2

2020-03-17T21:16:08Z

Signed-off-by: Junio C Hamano

Git 2.20.3

2020-03-17T20:46:10Z

Signed-off-by: Junio C Hamano

Git 2.19.4

2020-03-17T20:43:08Z

Signed-off-by: Junio C Hamano