added sql injection simulation for authentication on server

README.md

@@ -33,6 +33,7 @@ PGPASSWORD=asdfpassword
 
 !only listening on localhost is supported. DO NOT run this on a public ip.  
 
+- `/health`
 - `/setup-demo-db`
 - `/nuke-db`
 - `/fetch-all-users`
@@ -40,7 +41,9 @@ PGPASSWORD=asdfpassword
 ### SQL Injection
 
 - `/sql-execute`
+- `/login-sql`
 - `/secure-sql-execute`
+- `/secure-login-sql`
 - `/secure-get-user`
 
 #### 1. Parameterization of Queries

server/internal/db/db.go

@@ -50,7 +50,7 @@ func SetupDemoDb(w http.ResponseWriter, r *http.Request) {
 	username VARCHAR(50) UNIQUE NOT NULL,
 	email VARCHAR(100) NOT NULL,
 	password VARCHAR(100) NOT NULL
-    );`
+);`
 
 	// also avoid duplicate entries
 	insertDataSQL := `

server/internal/http_server/http_server.go

@@ -21,7 +21,9 @@ func ServeApi() {
 	http.HandleFunc("/nuke-db", db.NukeDb)
 	http.HandleFunc("/fetch-all-users", db.FetchAllUsers)
 	http.HandleFunc("/execute-sql", sql_injection.ExecuteSql)
+	http.HandleFunc("/login-sql", sql_injection.LoginSql)
 	http.HandleFunc("/secure-execute-sql", sql_injection.SecureExecuteSql)
+	http.HandleFunc("/secure-login-sql", sql_injection.SecureLoginSql)
 	http.HandleFunc("/secure-get-user", sql_injection.SecureGetUser)
 	log.Println("Server is running on http://localhost:5000")
 	if err := http.ListenAndServe(":5000", nil); err != nil {

server/internal/sql_injection/sql_injection.go

@@ -46,6 +46,50 @@ func ExecuteSql(w http.ResponseWriter, r *http.Request) {
 	w.Write([]byte(response))
 }
 
+// unsecure login
+// login endpoint with sql injection vulnerability
+func LoginSql(w http.ResponseWriter, r *http.Request) {
+	// parse the request body to get username and password
+	var credentials struct {
+		Username string `json:"username"`
+		Password string `json:"password"`
+	}
+
+	// decode the json body
+	if err := json.NewDecoder(r.Body).Decode(&credentials); err != nil {
+		http.Error(w, "Invalid request format", http.StatusBadRequest)
+		return
+	}
+	defer r.Body.Close()
+
+	// construct the unsafe query
+	query := fmt.Sprintf(
+		"SELECT id, username FROM users WHERE username = '%s' AND password = '&s'",
+		credentials.Username,
+		credentials.Password,
+	)
+
+	// execute the query without sanitizing the input
+	var id int
+	var username string
+	err := db.DbPool.QueryRow(context.Background(), query).Scan(&id, &username)
+	if err != nil {
+		http.Error(w, "Invalid credentials", http.StatusUnauthorized)
+		return
+	}
+
+	// if the user is found, return success response
+	response := map[string]interface{}{
+		"message":  "Login successful",
+		"user_id":  id,
+		"username": username,
+	}
+	if err := json.NewEncoder(w).Encode(response); err != nil {
+		http.Error(w, "Failed to encode response", http.StatusInternalServerError)
+		log.Printf("JSON encoding error: %v", err)
+	}
+}
+
 // secure version
 // only allow parameterized queries with validation
 func SecureExecuteSql(w http.ResponseWriter, r *http.Request) {
@@ -95,7 +139,7 @@ func SecureExecuteSql(w http.ResponseWriter, r *http.Request) {
 	// return json response
 	jsonResp, err := json.Marshal(response)
 	if err != nil {
-		http.Error(w, "Failed to encode response as JSON", http.StatusInternalServerError)
+		http.Error(w, "Failed to encode response", http.StatusInternalServerError)
 		return
 	}
 
@@ -103,6 +147,41 @@ func SecureExecuteSql(w http.ResponseWriter, r *http.Request) {
 	w.Write(jsonResp)
 }
 
+// secure login
+func SecureLoginSql(w http.ResponseWriter, r *http.Request) {
+	var credentials struct {
+		Username string `json:"username"`
+		Password string `json:"password"`
+	}
+
+	if err := json.NewDecoder(r.Body).Decode(&credentials); err != nil {
+		http.Error(w, "Invalid request format", http.StatusBadRequest)
+		return
+	}
+	defer r.Body.Close()
+
+	// secure version using parameterized queries
+	query := "SELECT id, username FROM users WHERE username = $1 AND password = $2"
+	var id int
+	var username string
+	err := db.DbPool.QueryRow(context.Background(), query, credentials.Username, credentials.Password).Scan(&id, &username)
+	if err != nil {
+		http.Error(w, "Invalid credentials", http.StatusUnauthorized)
+		return
+	}
+
+	// send back the response if great success
+	response := map[string]interface{}{
+		"message":  "Login successful",
+		"user_id":  id,
+		"username": username,
+	}
+	if err := json.NewEncoder(w).Encode(response); err != nil {
+		http.Error(w, "Failed to encode response", http.StatusInternalServerError)
+		log.Printf("JSON encoding error: %v", err)
+	}
+}
+
 // even more secure
 func SecureGetUser(w http.ResponseWriter, r *http.Request) {
 	// decode the json body