Injection Flaws in Chi with Cockroachdb

Chi is a minimal, composable router for building HTTP services in Go. When integrating Chi with CockroachDB, an open-source, cloud-native SQL database, injection flaws typically arise from improper handling of user input in SQL queries. Because CockroachDB speaks PostgreSQL wire protocol, common SQL injection patterns seen in other databases also apply. Injection flaws in this context occur when application code interpolates user-controlled data directly into query strings, enabling attackers to alter query structure, bypass authentication, or extract data.

In Chi, routes are matched using middleware and handlers; developers often extract parameters via chi.URLParam or from request bodies and query strings. If these values are passed to CockroachDB without proper parameterization, the resulting queries become vulnerable. For example, building a SQL string by concatenating a user-supplied identifier allows an attacker to inject additional SQL fragments. Even when using prepared statements, incorrect usage—such as dynamically constructing query text while only parameterizing values—can leave injection surfaces.

Consider an endpoint that retrieves user profiles by username using a path parameter:

// Unsafe example: string concatenation with user input
func getUserHandler(w http.ResponseWriter, r *http.Request) {
    username := chi.URLParam(r, "username")
    query := "SELECT id, email FROM users WHERE username = '" + username + "'"
    rows, err := db.Query(query)
    // handle error and rows
}

An attacker can provide admin' -- as the username, causing the query to become SELECT id, email FROM users WHERE username = 'admin' --', potentially bypassing intended filters or exposing other users’ data. This pattern violates the principle of separating code from data and exposes the application to classic SQL injection (CWE-89), which is part of the OWASP API Top 10 and relevant to compliance frameworks such as PCI-DSS and SOC2.

Another scenario involves dynamic query construction for filtering or sorting. If a developer builds an ORDER BY clause using raw input, injection can occur even when values are used in IN clauses. For instance:

// Unsafe: dynamic column name or order direction
column := chi.URLParam(r, "sort")
query := fmt.Sprintf("SELECT id, name FROM products ORDER BY %s", column)

Here, an attacker can manipulate the sort parameter to include SQL fragments, such as 1; DROP TABLE users; --, leading to data loss or schema manipulation. CockroachDB’s PostgreSQL compatibility means that standard SQL injection mitigation techniques apply, but the database’s distributed nature does not reduce the risk.

The LLM/AI Security checks unique to middleBrick specifically look for scenarios where system prompts or model behavior might inadvertently expose query patterns or sensitive logic, but the root cause remains insecure handling of input in application code. Injection flaws in Chi with CockroachDB are fundamentally a development practice issue: queries must be parameterized, identifiers must be validated against a strict allowlist, and dynamic SQL should be constructed with extreme caution.

Remediation centers on strict use of parameterized queries and disciplined schema handling. For value substitutions, always use placeholders supported by CockroachDB’s PostgreSQL wire protocol. The database/sql package ensures that parameters are sent separately from query text, preventing injection.

Safe retrieval using placeholders:

// Safe: parameterized query for values
func getUserHandler(w http.ResponseWriter, r *http.Request) {
    username := chi.URLParam(r, "username")
    query := "SELECT id, email FROM users WHERE username = $1"
    row := db.QueryRow(query, username)
    // handle row
}

Note the use of $1 as a positional placeholder, which CockroachDB understands. This ensures the username is treated strictly as a value, not executable SQL.

For dynamic identifiers such as column or table names, parameterization is not supported; instead, validate input against a strict allowlist:

// Safe: allowlist validation for identifiers
var allowedColumns = map[string]bool{"name": true, "created_at": true, "price": true}

func listProducts(w http.ResponseWriter, r *http.Request) {
    sort := chi.URLParam(r, "sort")
    if !allowedColumns[sort] {
        http.Error(w, "invalid sort column", http.StatusBadRequest)
        return
    }
    query := fmt.Sprintf("SELECT id, name FROM products ORDER BY %s", sort)
    rows, err := db.Query(query)
    // handle error and rows
}

Additionally, avoid constructing query strings from request bodies for write operations. Use named parameters consistently:

// Safe: inserting with named parameters
func createUser(w http.ResponseWriter, r *http.Request) {
    var u struct {
        Name  string
        Email string
    }
    if err := json.NewDecoder(r.Body).Decode(&u); err != nil {
        http.Error(w, "invalid request body", http.StatusBadRequest)
        return
    }
    query := "INSERT INTO users (name, email) VALUES ($1, $2)"
    _, err := db.Exec(query, u.Name, u.Email)
    // handle error
}

When using higher-level libraries that build queries, ensure they generate parameterized statements and do not perform unsafe string interpolation. Regular security scans using tools like middleBrick’s CLI can help detect injection-prone patterns in Chi handlers:

# Scan the service from terminal
middlebrick scan https://api.example.com

For teams integrating into development workflows, the GitHub Action can enforce security gates by failing builds when risk scores exceed defined thresholds, while the MCP Server enables scanning API endpoints directly from AI coding assistants within the IDE.