Always index locally for prefetch packs#1840
Merged
mjcheetham merged 1 commit intomicrosoft:masterfrom Jun 13, 2025
Merged
Conversation
The GVFS protocol includes an index file along with pack file in the prefetch workflow (primarily used on a new clone to fetch all commits and trees). Currently, GVFS blindly accepts that index file. This pull request changes GVFS prefetch to discard the index sent by the server and always create an index locally. This provides improved security and verification of the pack file, at the expense of performance for the first clone of a repository on a new drive.
mjcheetham
approved these changes
Jun 13, 2025
Member
mjcheetham
left a comment
mjcheetham
left a comment
There was a problem hiding this comment.
Thanks for being vigilant here! Of course this will result in a performance penalty, but security is more important.
Comment on lines
+709
to
+710
| // We can't trust the index file from the server, so we will always build our own. | ||
| // We still need to consume and handle any exceptions from the index stream though. |
Member
There was a problem hiding this comment.
I wonder if we may want to add an option to use the pack index as given by the server (default to ignore it of course) for performance critical scenarios where we can also trust the server.
For now let's just be safe and never trust the pack index, and can add this in the future if needed.
Merged
This was referenced Jun 16, 2025
This file contains hidden or 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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
The GVFS protocol includes an index file along with pack file in the prefetch workflow (primarily used on a new clone to fetch all commits and trees).
Currently, GVFS accepts that index file without any verification.
This pull request changes GVFS prefetch to discard the index sent by the server and always create an index locally. This provides improved security and verification of the pack file, at the expense of performance for the first clone of a repository with a new local cache.