rpc : prevent crashes on invalid input

Add more checks which prevent RPC server from crashing if invalid input
is received from client

Author: rgerganov

ggml/src/ggml-rpc.cpp

@@ -1098,13 +1098,23 @@ static void rpc_serve_client(ggml_backend_t backend, sockfd_t sockfd, size_t fre
         if (!recv_data(sockfd, &cmd, 1)) {
             break;
         }
+        if (cmd > GET_DEVICE_MEMORY) {
+            // fail fast if the command is invalid
+            fprintf(stderr, "Unknown command: %d\n", cmd);
+            break;
+        }
         std::vector<uint8_t> input;
         std::vector<uint8_t> output;
         uint64_t input_size;
         if (!recv_data(sockfd, &input_size, sizeof(input_size))) {
             break;
         }
-        input.resize(input_size);
+        try {
+            input.resize(input_size);
+        } catch (const std::bad_alloc & e) {
+            fprintf(stderr, "Failed to allocate input buffer of size %" PRIu64 "\n", input_size);
+            break;
+        }
         if (!recv_data(sockfd, input.data(), input_size)) {
             break;
         }
@@ -1203,8 +1213,10 @@ void start_rpc_server(ggml_backend_t backend, const char * endpoint, size_t free
             return;
         }
         printf("Accepted client connection, free_mem=%zu, total_mem=%zu\n", free_mem, total_mem);
+        fflush(stdout);
         rpc_serve_client(backend, client_socket->fd, free_mem, total_mem);
         printf("Client connection closed\n");
+        fflush(stdout);
     }
 #ifdef _WIN32
     WSACleanup();