pyckle commented on code in PR #362: URL: https://github.com/apache/mina-sshd/pull/362#discussion_r1174612833
########## sshd-common/src/main/java/org/apache/sshd/common/util/io/IoUtils.java: ########## @@ -637,4 +677,75 @@ public static List<String> readAllLines(BufferedReader reader, int lineCountHint } return result; } + + /** + * Chroot a path under the new root + * + * @param newRoot the new root + * @param toSanitize the path to sanitize and chroot + * @return the chrooted path under the newRoot filesystem + */ + public static Path chroot(Path newRoot, Path toSanitize) { + Objects.requireNonNull(newRoot); + Objects.requireNonNull(toSanitize); + List<String> sanitized = removeExtraCdUps(toSanitize); + return buildPath(newRoot, newRoot.getFileSystem(), sanitized); + } + + /** + * Remove any extra directory ups from the Path + * + * @param toSanitize the path to sanitize + * @return the sanitized path + */ + public static Path removeCdUpAboveRoot(Path toSanitize) { + List<String> sanitized = removeExtraCdUps(toSanitize); + return buildPath(toSanitize.getRoot(), toSanitize.getFileSystem(), sanitized); + } + + private static List<String> removeExtraCdUps(Path toResolve) { + List<String> newNames = new ArrayList<>(toResolve.getNameCount()); + + int numCdUps = 0; + int numDirParts = 0; + for (int i = 0; i < toResolve.getNameCount(); i++) { + String name = toResolve.getName(i).toString(); + if ("..".equals(name)) { + // If we have more cdups than dir parts, so we ignore the ".." to avoid jail escapes + if (numDirParts > numCdUps) { + ++numCdUps; + newNames.add(name); + } + } else { + // if the current directory is a part of the name, don't increment number of dir parts, as it doesn't + // add to the number of ".."s that can be present before the root + if (!".".equals(name)) { + ++numDirParts; + } + newNames.add(name); + } + } + return newNames; + } + + private static Path buildPath(Path root, FileSystem fs, List<String> namesList) { Review Comment: I can agree with this approach in many situations, but there's no practical use case here. Having a `Set` (or any other unordered collection for that matter) for a set of path components makes absolutely no sense. The `Collection` type in the signature only will confuse a developer as the signature doesn't semantically reflect what the function accomplishes. And if this scenario was a use case (which I would be very curious to see), calling `buildPath(..., new ArrayList(namesCollection),...)` would be an easy way to use this function. With that said, I'm not a maintainer, and I made a PR for @gnodet which makes this change (and addresses the other issues) here: https://github.com/gnodet/mina-sshd/pull/2/files -- 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: dev-unsubscr...@mina.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@mina.apache.org For additional commands, e-mail: dev-h...@mina.apache.org