fix: update the gossip message size checks

ChainSafe · Dec 6, 2024 · bfece62 · bfece62
1 parent cd1211f
commit bfece62
Showing 1 changed file with 8 additions and 1 deletion.
diff --git a/packages/beacon-node/src/network/gossip/encoding.ts b/packages/beacon-node/src/network/gossip/encoding.ts
@@ -69,6 +69,7 @@ export function msgIdFn(gossipTopicCache: GossipTopicCache, msg: Message): Uint8
 export class DataTransformSnappy implements DataTransform {
   constructor(
     private readonly gossipTopicCache: GossipTopicCache,
+    /** size of the compressed message */
     private readonly maxSizePerMessage: number
   ) {}
 
@@ -79,7 +80,13 @@ export class DataTransformSnappy implements DataTransform {
    * - `outboundTransform()`: compress snappy payload
    */
   inboundTransform(topicStr: string, data: Uint8Array): Uint8Array {
-    const uncompressedData = uncompress(data, this.maxSizePerMessage);
+    if (data.length > this.maxSizePerMessage) {
+      throw Error(`ssz_snappy data length ${data.length} > maxSizePerMessage`);
+    }
+
+    // snappy compression efficiency is around ~36% so the max uncompressed bound
+    // should be 3X
+    const uncompressedData = uncompress(data, 3 * this.maxSizePerMessage);
 
     // check uncompressed data length before we extract beacon block root, slot or
     // attestation data at later steps