diff --git a/.jules/sentinel.md b/.jules/sentinel.md index 80620ce..b3d3f97 100644 --- a/.jules/sentinel.md +++ b/.jules/sentinel.md @@ -16,3 +16,7 @@ **Vulnerability:** Writing fully buffered in-memory data to temporary disk files solely for parsing. **Learning:** This increases attack surface, risks disk exhaustion, and violates the principle of least privilege. **Prevention:** Refactor parsing functions to accept byte slices or `io.Reader` directly to process data in memory. +## 2024-11-20 - SSRF Prevention with net.Dialer +**Vulnerability:** Untrusted user-provided URLs could access cloud metadata endpoints via Server-Side Request Forgery (SSRF) because `http.Get()` was used without preventing IP resolution to known restricted IPs. +**Learning:** Using a custom `net.Dialer` with a `Control` hook prevents SSRF by evaluating the resolved IP address *after* DNS resolution but *before* the socket connects. This stops DNS rebinding and IP obfuscation attacks. +**Prevention:** Block specific cloud metadata IPs like `169.254.169.254` in the `Control` hook. Ensure IPv6 Zone Identifiers are stripped before parsing. diff --git a/internal/plugin/manager.go b/internal/plugin/manager.go index 7aad027..6a1cbd7 100644 --- a/internal/plugin/manager.go +++ b/internal/plugin/manager.go @@ -7,6 +7,7 @@ import ( "encoding/json" "fmt" "io" + "net" "net/http" "net/url" "os" @@ -16,6 +17,7 @@ import ( "runtime" "sort" "strings" + "syscall" "time" "github.com/himattm/prism/internal/fsutil" @@ -410,7 +412,8 @@ func (m *Manager) addScriptPlugin(owner, repo, pluginName string) error { fmt.Printf("Fetching script from: %s\n", rawURL) - resp, err := http.Get(rawURL) + client := newSafeClient(10 * time.Second) + resp, err := client.Get(rawURL) if err != nil { return fmt.Errorf("failed to fetch plugin: %w", err) } @@ -468,7 +471,8 @@ func (m *Manager) addFromDirectURL(rawURL string) error { return fmt.Errorf("unsupported URL scheme: %s", parsedURL.Scheme) } - resp, err := http.Get(parsedURL.String()) + client := newSafeClient(10 * time.Second) + resp, err := client.Get(parsedURL.String()) if err != nil { return fmt.Errorf("failed to fetch plugin: %w", err) } @@ -860,3 +864,31 @@ func CompareVersions(a, b string) int { return 0 } + +func newSafeClient(timeout time.Duration) *http.Client { + transport := http.DefaultTransport.(*http.Transport).Clone() + transport.DisableKeepAlives = true + dialer := &net.Dialer{ + Timeout: 30 * time.Second, + KeepAlive: 30 * time.Second, + Control: func(network, address string, c syscall.RawConn) error { + host, _, err := net.SplitHostPort(address) + if err != nil { + return err + } + if idx := strings.IndexByte(host, '%'); idx != -1 { + host = host[:idx] + } + ip := net.ParseIP(host) + if ip != nil && ip.String() == "169.254.169.254" { + return fmt.Errorf("access to cloud metadata IP is forbidden") + } + return nil + }, + } + transport.DialContext = dialer.DialContext + return &http.Client{ + Timeout: timeout, + Transport: transport, + } +}