The Redis protocol implementation in Apache bRPC allowed inline command parsing to allocate and...

The Redis protocol implementation in Apache bRPC allowed inline command parsing to allocate and copy the full connection buffer before a complete CRLF-terminated command was available. A remote attacker with access to a Redis-protocol bRPC service could send long inline inputs without a terminating CRLF to increase memory usage and CPU copy overhead, potentially causing denial of service.

Root Cause:
The Redis inline command parser allocated memory based on the current input buffer size and copied the entire buffer before determining the current inline command boundary. The existing redis_max_allocation_size limit was applied to RESP bulk strings and arrays, but not effectively to the inline command path before allocation.

Affected Scenarios:
Use Apache bRPC server with Redis protocol enabled and reachable by untrusted clients.

How to Fix:

1. Upgrade Apache bRPC to version 1.18.0, which fixes this issue.
2. Apply the patch from PR https://github.com/apache/brpc/pull/3363 .

Note:
The fix applies redis_max_allocation_size to Redis inline command lines and scans for CRLF before allocating parser arena memory. Inline command lines exceeding this limit are rejected.