Enshuring ProxySQL's stability when subjected to malformed packets

lib/MySQL_Protocol.cpp

@@ -1595,6 +1595,10 @@ int MySQL_Protocol::PPHR_1(unsigned char *pkt, unsigned int len, bool& ret, MyPr
 
 // this function was inline in process_pkt_handshake_response() , split for readibility
 bool MySQL_Protocol::PPHR_2(unsigned char *pkt, unsigned int len, bool& ret, MyProt_tmp_auth_vars& vars1) { // process_pkt_handshake_response inner 2
+
+	// if packet length is less than 4, it's a malformed packet.
+	if ((len - sizeof(mysql_hdr)) < 4) return false;
+
 	vars1.capabilities = CPY4(pkt);
 	// see bug #2916. If CLIENT_MULTI_STATEMENTS is set by the client
 	// we enforce setting CLIENT_MULTI_RESULTS, this is the proper and expected

lib/MySQL_Session.cpp

@@ -3954,13 +3954,6 @@ __get_pkts_from_client:
 			client_myds->PSarrayIN->remove_index(0,&pkt);
 		}
 
-		if (pkt.size <= sizeof(mysql_hdr)) {
-			proxy_debug(PROXY_DEBUG_MYSQL_COM, 5, "Malformed packet received\n");
-			l_free(pkt.size, pkt.ptr);
-			handler_ret = -1;
-			return handler_ret;
-		}
-
 		switch (status) {
 			case WAITING_CLIENT_DATA:
 				if (pkt.size==(0xFFFFFF+sizeof(mysql_hdr))) { // we are handling a multi-packet

test/tap/tests/mysql-test_malformed_packet-t.cpp

@@ -0,0 +1,174 @@
+/**
+ * @file mysql-test_malformed_packet-t.cpp
+ * @brief Validates ProxySQL's stability and ensures it does not crash when subjected to 
+ *       multiple malformed packets on its admin and backend connections.
+ */
+#include <unistd.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include "mysql.h"
+#include "tap.h"
+#include "command_line.h"
+#include "utils.h"
+
+constexpr size_t BUFFER_SIZE = 1024;
+
+#define REPORT_ERROR_AND_EXIT(fmt, ...) \
+    do { \
+        fprintf(stderr, "File %s, line %d: " fmt "\n", __FILE__, __LINE__, ##__VA_ARGS__); \
+        close(sock); \
+        return; \
+    } while (0)
+
+typedef enum {
+        BACKEND = 0,
+        ADMIN
+} Connection_type_t;
+
+void execute_test(MYSQL* conn, const std::string& host, int port, const std::vector<uint8_t>& data) {
+    int sock = socket(AF_INET, SOCK_STREAM, 0);
+    if (sock < 0) {
+        REPORT_ERROR_AND_EXIT("Socket creation failed");
+    }
+
+    struct timeval timeout;
+    // Set the timeout for receive operations
+    timeout.tv_sec = 60;  
+    timeout.tv_usec = 0; 
+    if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout)) < 0) {
+        REPORT_ERROR_AND_EXIT("Failed to set socket timeout");
+    }
+
+    sockaddr_in server_addr{};
+    server_addr.sin_family = AF_INET;
+    server_addr.sin_port = htons(port);
+
+    if (inet_pton(AF_INET, host.c_str(), &server_addr.sin_addr) <= 0) {
+        REPORT_ERROR_AND_EXIT("Invalid address or address not supported");
+    }
+
+    if (connect(sock, (struct sockaddr*)&server_addr, sizeof(server_addr)) < 0) {
+        REPORT_ERROR_AND_EXIT("Connection to the server failed");
+    }
+
+    diag("Connected to the server. Waiting for server greeting...");
+
+    std::vector<char> buffer(BUFFER_SIZE);
+    ssize_t bytes_received = recv(sock, buffer.data(), buffer.size(), 0);
+    if (bytes_received < 0) {
+        REPORT_ERROR_AND_EXIT("Failed to receive server greeting");
+    }
+
+    diag("Server greeting received (length: %ld bytes).", bytes_received);
+
+    diag("Sending malformed packet to the server...");
+    ssize_t bytes_sent = send(sock, data.data(), data.size(), 0);
+    if (bytes_sent < 0) {
+        REPORT_ERROR_AND_EXIT("Failed to send data");
+    }
+    diag("Done");
+
+    bytes_received = recv(sock, buffer.data(), buffer.size(), 0);
+    ok(bytes_received == 0, "Connection closed by server");
+    close(sock);
+
+    usleep(1000000); // 1 second delay
+
+	bool query_success = false;
+
+    if (mysql_query(conn, "SELECT 1")) {
+        fprintf(stderr, "mysql_query() failed: %s\n", mysql_error(conn));
+    } else {
+
+        MYSQL_RES* result = mysql_store_result(conn);
+        if (result == nullptr) {
+            fprintf(stderr, "mysql_store_result() failed: %s\n", mysql_error(conn));
+		}
+		else {
+			MYSQL_ROW row = mysql_fetch_row(result);
+			if (row && strcmp(row[0], "1") == 0) query_success = true;
+			mysql_free_result(result);
+		}
+    }
+
+    ok(query_success, "ProxySQL should be alive. %s", mysql_error(conn));
+}
+
+MYSQL* setup_mysql_connection(const CommandLine& cl, Connection_type_t conn_type) {
+    MYSQL* conn = mysql_init(nullptr);
+    if (conn == nullptr) {
+        fprintf(stderr, "File %s, line %d, Error: mysql_init() failed\n", __FILE__, __LINE__);
+        return nullptr;
+    }
+
+    if (conn_type == ADMIN) {
+        if (!mysql_real_connect(conn, cl.admin_host, cl.admin_username, cl.admin_password, nullptr, cl.admin_port, nullptr, 0)) {
+            fprintf(stderr, "File %s, line %d, Error: %s\n", __FILE__, __LINE__, mysql_error(conn));
+            mysql_close(conn);
+            return nullptr;
+        }
+    } else {
+        if (!mysql_real_connect(conn, cl.host, cl.username, cl.password, nullptr, cl.port, nullptr, 0)) {
+            fprintf(stderr, "File %s, line %d, Error: %s\n", __FILE__, __LINE__, mysql_error(conn));
+            mysql_close(conn);
+            return nullptr;
+        }
+    }
+
+    return conn;
+}
+
+int main(int argc, char** argv) {
+    CommandLine cl;
+
+    if (cl.getEnv()) {
+        diag("Failed to get the required environmental variables.");
+        return EXIT_FAILURE;
+    }
+
+    std::vector<std::vector<uint8_t>> malformed_pkts = {
+        {0x01, 0x00},
+        {0xFF, 0xFF, 0xFF, 0x00, 0x00, 0xFE, 0x00, 0x00},
+        {0x03, 0x00, 0x00, 0xFF, 0x00},
+        {0x10, 0x00, 0x00, 0x00, 0xDE, 0xAD, 0xBE, 0xEF, 0xCA, 0xFE, 0x11, 0x22, 0x33, 0x44, 0x55},
+        {0x03, 0x00, 0x00, 0x00, 0xFF, 0x00},
+        {0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00},
+        {0x05, 0x00, 0x00, 0x00, 0xFF, 0x00, 0x00, 0x00},
+        {0x04, 0x00, 0x00, 0xFF, 0x00, 0x00, 0x00},
+        {0x03, 0x00, 0x00, 0x2F, 0x2A, 0xE0, 0x00},
+    };
+
+    plan(malformed_pkts.size() * 4);
+
+    {
+        diag(">>> Sending malformed packets to BACKEND connection <<<");
+        MYSQL* conn = setup_mysql_connection(cl, BACKEND);
+        if (conn == nullptr) {
+            return EXIT_FAILURE;
+        }
+
+        for (const auto& pkt : malformed_pkts) {
+            execute_test(conn, cl.host, cl.port, pkt);
+        }
+
+        mysql_close(conn);
+        diag("Done");
+    }
+
+    {
+        diag(">>> Sending malformed packets to ADMIN connection <<<");
+        MYSQL* conn = setup_mysql_connection(cl, ADMIN);
+        if (conn == nullptr) {
+            return EXIT_FAILURE;
+        }
+
+        for (const auto& pkt : malformed_pkts) {
+            execute_test(conn, cl.host, cl.port, pkt);
+        }
+
+        mysql_close(conn);
+        diag("Done");
+    }
+
+    return exit_status();
+}