Bugfix: Handle directories uploaded into zip file. #3327
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
A Zip archive only contains files and has no concept of directories. If the upload() VQL function is accidentally called on a directory, Velociraptor will try to read the directory and store it in the zip file. This leads to a 0 length file placed in the middle of a directory path: /Foo/Bar <- zero length file /Foo/Bar/Baz <- a real file. This makes the real file impossible to extract and third party zip programs will be unable to write it once they created a file at the directory level above. This also confuses Velociraptor's zip accessor which emulates directories based on path prefixes and see /Foo/Bar as a file not a directory (so it does not recurse into it). This PR ensures that when a directory is passed to upload() it will have a trailing / appended. This seems to be a convention with zip programs to denote a directory in a zip file. Additionally we consider a zero length file in the zip archive to be a directory regardless if it has a trailing / in order to be able to recover older collections which were written without the trailing /.
scudette
added a commit
that referenced
this pull request
Mar 10, 2024
A Zip archive only contains files and has no concept of directories. If the upload() VQL function is accidentally called on a directory, Velociraptor will try to read the directory and store it in the zip file. This leads to a 0 length file placed in the middle of a directory path: /Foo/Bar <- zero length file /Foo/Bar/Baz <- a real file. This makes the real file impossible to extract and third party zip programs will be unable to write it once they created a file at the directory level above. This also confuses Velociraptor's zip accessor which emulates directories based on path prefixes and see /Foo/Bar as a file not a directory (so it does not recurse into it). This PR ensures that when a directory is passed to upload() it will have a trailing / appended. This seems to be a convention with zip programs to denote a directory in a zip file. Additionally we consider a zero length file in the zip archive to be a directory regardless if it has a trailing / in order to be able to recover older collections which were written without the trailing /.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
A Zip archive only contains files and has no concept of directories. If the upload() VQL function is accidentally called on a directory, Velociraptor will try to read the directory and store it in the zip file. This leads to a 0 length file placed in the middle of a directory path:
/Foo/Bar <- zero length file
/Foo/Bar/Baz <- a real file.
This makes the real file impossible to extract and third party zip programs will be unable to write it once they created a file at the directory level above. This also confuses Velociraptor's zip accessor which emulates directories based on path prefixes and see /Foo/Bar as a file not a directory (so it does not recurse into it).
This PR ensures that when a directory is passed to upload() it will have a trailing / appended. This seems to be a convention with zip programs to denote a directory in a zip file. Additionally we consider a zero length file in the zip archive to be a directory regardless if it has a trailing / in order to be able to recover older collections which were written without the trailing /.