pkg/rpcserver: pkg/flatrpc: executor: add handshake stage 0 #5808
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
ramosian-glider
force-pushed
the
rpc-handshake
branch
3 times, most recently
from
32a2b2b to
70e95ce
Compare
|
Please note the commit description change in the latest pushes |
tarasmadan
reviewed
Feb 20, 2025
ramosian-glider
force-pushed
the
rpc-handshake
branch
6 times, most recently
from
b0b0c77 to
688307b
Compare
As we figured out in google#5805, syz-manager treats random incoming RPC connections as trusted, and will crash if a non-executor client sends an invalid packet to it. To address this issue, we introduce another stage of handshake, which includes a cookie exchange: - upon connection from an executor, the manager sends a ConnectHello RPC message to it, which contains a random 64-bit cookie; - the executor calculates a hash of that cookie and includes it into its ConnectRequest together with the other information; - before checking the validity of ConnectRequest, the manager ensures client sanity (passed ID didn't change, hashed cookie has the expected value) We deliberately pick a random cookie instead of a magic number: if the fuzzer somehow learns to send packets to the manager, we don't want it to crash multiple managers on the same machine.
ramosian-glider
force-pushed
the
rpc-handshake
branch
from
688307b to
3f1bbd4
Compare
tarasmadan
approved these changes
Feb 20, 2025
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Outdated suggestions cannot be applied.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.
As we figured out in #5805, syz-manager treats random incoming RPC connections as trusted, and will crash if a non-executor client sends an invalid packet to it.
To address this issue, we introduce another stage of handshake, which includes a cookie exchange:
We deliberately pick a random cookie instead of a magic number: if the fuzzer somehow learns to send packets to the manager, we don't want it to crash multiple managers on the same machine.
Before sending a pull request, please review Contribution Guidelines:
https://github.com/google/syzkaller/blob/master/docs/contributing.md