rootvector2 opened a new pull request, #792: URL: https://github.com/apache/commons-vfs/pull/792
`UriParser` decodes `%0D%0A` in a name to a real CRLF, `FtpFileObject` keeps that as its `relPath`, and `commons-net` writes `<command> <arg>CRLF` with no check of its own. Resolving `folder%0D%0ADELE%20secret.txt` against an application's own FTP base and calling `createFolder()` makes the server run `MKD folder` and then the caller's `DELE secret.txt` on the authenticated session, and every command built from `relPath` is affected the same way (`MKD`, `DELE`, `RMD`, `RETR`, `STOR`, `APPE`, `RNFR`/`RNTO`, `LIST`, `CWD`, `MDTM`). Found while checking which providers write a VFS name into a line-oriented protocol; `doGetChildren` has the same splice for a symlink target the remote server supplies, so both sites are covered. `FtpFileObject` is where VFS turns a `FileName` into an FTP command argument, so the path is refused there rather than in each of the `FtpClient` methods. No valid FTP path can hold a carriage return or line feed, so names that resolve today keep resolving; the new `FtpCommandInjectionTest` fails on the current code and passes with the change. - [x] Read the [contribution guidelines](CONTRIBUTING.md) for this project. - [x] Read the [ASF Generative Tooling Guidance](https://www.apache.org/legal/generative-tooling.html) if you use Artificial Intelligence (AI). - [x] I used AI to create any part of, or all of, this pull request. Which AI tool was used to create this pull request, and to what extent did it contribute? Claude Code, to trace the decoded path from `UriParser` through to the `commons-net` command writer and to draft this patch and its test; I confirmed the injected command against the embedded FTP server and reviewed the result. - [x] Run a successful build using the default [Maven](https://maven.apache.org/) goal with `mvn`; that's `mvn` on the command line by itself. - [x] Write unit tests that match behavioral changes, where the tests fail if the changes to the runtime are not applied. This may not always be possible, but it is a best practice. - [x] Write a pull request description that is detailed enough to understand what the pull request does, how, and why. - [x] Each commit in the pull request should have a meaningful subject line and body. Note that a maintainer may squash commits during the merge process. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
