[201811][dhcp_relay] Check payload size to prevent buffer overflow in dhcpv6 option #10252
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
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Outdated suggestions cannot be applied.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.
This is a cherry-pick of #9740
Why I did it
When parsing through relay reply packets, parse_dhcpv6_option introduces vulnerability in buffer overflow, allowing up to 2 byte/65535 copied into a fixed buffer of size 4096.
How I did it
Add bound checks to before and after option parsing
How to verify it
Send a dummy packet with option length greater than 4096. dhcp6relay should not perform memcpy on invalid option length.
Which release branch to backport (provide reason below if selected)
Description for the changelog
A picture of a cute animal (not mandatory but encouraged)