ucm: fix TOCTOU race condition #367
Open
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
Separately checking the state of a file before operating on it may allow an attacker to modify the file between the two operations. Fix by calling readlink first. If that fails, then path should not be a symbolic link and we call open() followed by fstat(). open() with O_NOFOLLOW will return an error if the file is a symlink. Signed-off-by: Mingjie Shen <shen497@purdue.edu>
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Outdated suggestions cannot be applied.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.
Separately checking the state of a file before operating on it may allow an attacker to modify the file between the two operations. Fix by calling readlink first. If that fails, then path should not be a symbolic link and we call open() followed by fstat(). open() with O_NOFOLLOW will return an error if the file is a symlink.