Fix potential DoS with responding to responses #247
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
An attacker could send a packet with the source address and port being resolved's, which will make resolved send the response to itself. But resolved responds to an unexpected response by sending a format error *response*. Which would go back to itself, again, triggering an infinite loop of responses. Much as it pains me to just drop a perfectly decodable, but invalid, message, this is the best solution since there isn't really a way to reliably tell if an attacker is triggering this case (eg, they could use two instances running on different IPs and bounce responses between them). See #246
barrucadu
added a commit
to barrucadu/nixfiles
that referenced
this pull request
Jun 2, 2023
Fixes a potential DoS issue[1] [1] barrucadu/resolved#247
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Outdated suggestions cannot be applied.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.
An attacker could send a packet with the source address and port being resolved's, which will make resolved send the response to itself. But resolved responds to an unexpected response by sending a format error response. Which would go back to itself, again, triggering an infinite loop of responses.
Much as it pains me to just drop a perfectly decodable, but invalid, message, this is the best solution since there isn't really a way to reliably tell if an attacker is triggering this case (eg, they could use two instances running on different IPs and bounce responses between them).
Fixes #246