Broken Access Control in Gin with Cockroachdb

Broken Access Control occurs when an API fails to enforce proper authorization checks, allowing one user to access or modify another user’s resources. When using the Gin framework with Cockroachdb as the backend, the risk emerges from a mismatch between route-level authorization logic and the data-access layer implemented against Cockroachdb. Gin does not provide built-in authorization; it relies on developers to enforce role-based or ownership checks before issuing database queries. If these checks are missing, incomplete, or bypassed (for example by trusting client-supplied identifiers), an attacker can manipulate request parameters to access records they should not see or modify.

With Cockroachdb, a distributed SQL database, developers often construct queries by interpolating user input directly into SQL strings or by using ORM-style query builders. If the query does not incorporate the authenticated user’s identity or tenant context, a request like /users/123/profile might execute SELECT * FROM profiles WHERE id = $1 with 123 taken directly from the URL. An attacker can change 123 to another ID and, without server-side authorization checks, retrieve or update another user’s profile. This is a classic BOLA (Broken Object Level Authorization) pattern, cataloged in the OWASP API Security Top 10, and it is especially dangerous when the database enforces row-level security weakly or not at all.

Another vector specific to Gin and Cockroachdb is insufficient enforcement of role-based rules at the API layer. For example, an endpoint intended for administrators might rely on a custom middleware that checks a claim in a JWT, but if the middleware is not applied consistently or if the handler still queries Cockroachdb without revalidating scope, a user with a modified token can execute privileged operations. Cockroachdb’s SQL interface does not inherently understand application roles; it executes queries with the privileges of the connected user. If the application uses a single database user or over-privileged connection string, a compromised API key or token can lead to widespread data exposure or destructive operations across tenants.

Additionally, pagination and filtering parameters can introduce access control flaws. An endpoint like /api/v1/orders?page=2&size=20 might construct a Cockroachdb query with LIMIT and OFFSET but omit a filter such as tenant_id = current_user_tenant(). This can result in an attacker iterating through offsets and reading orders belonging to other tenants. Because Cockroachdb supports geo-partitioning and secondary indexes, missing tenant filters can cause cross-partition data leaks that are difficult to detect without thorough audit logging and runtime analysis.

To remediate Broken Access Control in Gin with Cockroachdb, you must enforce authorization checks in every handler, parameterize all SQL queries, and embed the authenticated user’s identity and tenant context into every database operation. Below are concrete, working examples that demonstrate secure patterns.

1. Enforce ownership checks with parameterized queries

Always include the authenticated user ID or tenant ID in the WHERE clause. This ensures that even if an attacker manipulates the URL, Cockroachdb returns zero rows rather than another user’s data.

// Example: Get user profile with ownership check
func GetProfile(c *gin.Context) {
    userID := c.Param("id")
    authID := c.MustGet("auth_user_id").(string) // from JWT or session

    var profile Profile
    row := db.QueryRow(context.Background(),
        "SELECT id, name, email FROM profiles WHERE id = $1 AND user_id = $2",
        userID, authID)
    if err := row.Scan(&profile.ID, &profile.Name, &profile.Email); err != nil {
        c.JSON(http.StatusNotFound, gin.H{"error": "not_found"})
        return
    }
    c.JSON(http.StatusOK, profile)
}

2. Use role-based middleware with database revalidation

Do not rely solely on token claims. After middleware validation, re-check critical permissions against a permissions table in Cockroachdb.

// Example: Admin-only endpoint with DB revalidation
func RequireAdmin(c *gin.Context) {
    userID := c.MustGet("auth_user_id").(string)

    var isAdmin bool
    err := db.QueryRow(context.Background(),
        "SELECT is_admin FROM users WHERE id = $1",
        userID).Scan(&isAdmin)
    if err != nil || !isAdmin {
        c.AbortWithStatusJSON(http.StatusForbidden, gin.H{"error": "forbidden"})
        return
    }
    c.Next()
}

3. Always filter by tenant ID in multi-tenant schemas

When using Cockroachdb with tenant-aware routing or row-level security, include the tenant ID in every query constructed by Gin handlers.

// Example: List orders scoped to tenant
func ListOrders(c *gin.Context) {
    tenantID := c.MustGet("tenant_id").(string)
    var orders []Order

    rows, err := db.Query(context.Background(),
        "SELECT id, total, status FROM orders WHERE tenant_id = $1 ORDER BY created_at DESC",
        tenantID)
    if err != nil {
        c.JSON(http.StatusInternalServerError, gin.H{"error": "server_error"})
        return
    }
    defer rows.Close()
    for rows.Next() {
        var o Order
        if err := rows.Scan(&o.ID, &o.Total, &o.Status); err != nil {
            c.JSON(http.StatusInternalServerError, gin.H{"error": "server_error"})
            return
        }
        orders = append(orders, o)
    }
    c.JSON(http.StatusOK, orders)
}

4. Apply principle of least privilege to database connections

Configure Cockroachdb connection pools and roles so the Gin application does not use a superuser account. Create a dedicated role with SELECT/INSERT/UPDATE limited to necessary tables and enforce via connection string parameters understood by your ORM or driver.

5. Validate and sanitize all user input before using in SQL

Even with parameterized queries, validate formats (e.g., UUID, integer IDs) to reduce accidental data exposure and injection risks. Use Gin’s binding and custom validators to ensure only well-formed identifiers reach the database layer.

By combining Gin middleware for authentication and tenant resolution with Cockroachdb-specific SQL practices—parameterized queries, row-level filtering, and role-based connection permissions—you reduce the attack surface for Broken Access Control and ensure that authorization is enforced consistently before any data is retrieved or modified.