derp/derphttp: fix nil pointer dereference when closing a netcheck client #5924
Conversation
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
bradfitz
reviewed
Oct 13, 2022
net/netcheck/netcheck.go
Outdated
Comment on lines
1191
to
1192
| // We intentionally do not Close() the derphttp Client, as it's only | ||
| // partially initialized. |
Member
There was a problem hiding this comment.
Can we make Close safe instead?
Otherwise I fear that static analysis like @odeke-em's from his https://github.com/tailscale/tailscale/pulls?q=is%3Apr+is%3Aclosed+author%3Aodeke-em+leaks changes will just keep flagging this as not closed and we'll be in this same position later.
Contributor
Author
There was a problem hiding this comment.
I figured the comment would be enough to get people not add Close() calls blindly, but you're right that other uses could crop up.
2c6f28f to
a446b21
Compare
bradfitz
approved these changes
Oct 13, 2022
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 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Outdated suggestions cannot be applied.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.
NewNetcheckClient only initializes a subset of fields of derphttp.Client, and it's exepcted that only DialRegionTLS is called on it. We do not need to close it (as added by #5707), and it's an error to do so.
Fixes #5919