8020e7b fix(web): restrict standalone video links and cache CSP · ermite

M .hexcheck.yaml +10 -1


@@ -26,6 +26,11 @@ components:
26	26		role: adapter
27	27		paths:
28	28		- internal/httprange/**
	29	+	mediapolicy:
	30	+	# Video host validation and CSP sources: shared HTTP infrastructure.
	31	+	role: adapter
	32	+	paths:
	33	+	- internal/mediapolicy/**
29	34		entrypoints:
30	35		# cmd/ermite only calls app.Run.
31	36		role: entrypoint

@@ -94,4 +99,8 @@ allow:
94	99		reason: rate-limits API clients with internal/clientlimit
95	100		- rule: no-adapter-to-adapter-imports
96	101		path: internal/adapters/web/**
97		-	reason: rate-limits login attempts with internal/clientlimit and selects byte ranges with internal/httprange
	102	+	reason: rate-limits login attempts with internal/clientlimit, selects byte ranges with internal/httprange and shares video hosts with internal/mediapolicy
	103	+
	104	+	- rule: no-adapter-to-adapter-imports
	105	+	path: internal/adapters/httpserver/**
	106	+	reason: shares external video hosts and CSP sources with internal/mediapolicy

     role: adapter
     paths:
       - internal/httprange/**
+  mediapolicy:
+    # Video host validation and CSP sources: shared HTTP infrastructure.
+    role: adapter
+    paths:
+      - internal/mediapolicy/**
   entrypoints:
     # cmd/ermite only calls app.Run.
     role: entrypoint
     reason: rate-limits API clients with internal/clientlimit
   - rule: no-adapter-to-adapter-imports
     path: internal/adapters/web/**
-    reason: rate-limits login attempts with internal/clientlimit and selects byte ranges with internal/httprange
+    reason: rate-limits login attempts with internal/clientlimit, selects byte ranges with internal/httprange and shares video hosts with internal/mediapolicy
+  - rule: no-adapter-to-adapter-imports
+    path: internal/adapters/httpserver/**
+    reason: shares external video hosts and CSP sources with internal/mediapolicy

M docs/configuration.md +4 -2


@@ -102,8 +102,10 @@ This build uses storage schema 6. Once it has run on your data, an older ermite
102	102		Trusted Markdown renders video images (`![label](clip.mp4)`, also `.webm`, `.mov`,
103	103		`.m4v` and `.ogv`) as native players. Repository-relative destinations use the raw
104	104		route of the viewed ref; external HTTP(S) destinations require an
105		-	`ERMITE_VIDEO_HOSTS` host. A standalone link or autolink to an allowed host also
106		-	renders as a player, including extensionless GitHub user-attachment URLs.
	105	+	`ERMITE_VIDEO_HOSTS` host. A standalone link or autolink to an allowed host
	106	+	renders as a player only when its path has a supported video extension or is an
	107	+	extensionless GitHub `github.com/user-attachments/assets/<id>` URL. Repository,
	108	+	issue and other ordinary URLs stay links.
107	109		Other images show their alt text; other links keep the existing link policy.
108	110		Raw HTML stays disabled. Untrusted public issue Markdown never loads videos.
109	111		Raw video types are detected by bytes, not extensions. Seeking supports single

 Trusted Markdown renders video images (`![label](clip.mp4)`, also `.webm`, `.mov`,
 `.m4v` and `.ogv`) as native players. Repository-relative destinations use the raw
 route of the viewed ref; external HTTP(S) destinations require an
-`ERMITE_VIDEO_HOSTS` host. A standalone link or autolink to an allowed host also
+`ERMITE_VIDEO_HOSTS` host. A standalone link or autolink to an allowed host
-renders as a player, including extensionless GitHub user-attachment URLs.
+renders as a player only when its path has a supported video extension or is an
+extensionless GitHub `github.com/user-attachments/assets/<id>` URL. Repository,
+issue and other ordinary URLs stay links.
 Other images show their alt text; other links keep the existing link policy.
 Raw HTML stays disabled. Untrusted public issue Markdown never loads videos.
 Raw video types are detected by bytes, not extensions. Seeking supports single

M internal/adapters/httpserver/middleware.go +2 -1


@@ -33,9 +33,10 @@ func isHTTPS(publicURL string) bool {
33	33		// the handler runs, so that errors and 404s carry them too. With hsts, the
34	34		// browser is told to stay on https.
35	35		func withSecurityHeaders(next http.Handler, hsts bool, hosts []string) http.Handler {
	36	+	csp := contentSecurityPolicy + "; media-src 'self' " + mediapolicy.Sources(hosts)
36	37		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
37	38		h := w.Header()
38		-	h.Set("Content-Security-Policy", contentSecurityPolicy+"; media-src 'self' "+mediapolicy.Sources(hosts))
	39	+	h.Set("Content-Security-Policy", csp)
39	40		h.Set("X-Frame-Options", "DENY")
40	41		h.Set("X-Content-Type-Options", "nosniff")
41	42		h.Set("Referrer-Policy", "same-origin")

 // the handler runs, so that errors and 404s carry them too. With hsts, the
 // browser is told to stay on https.
 func withSecurityHeaders(next http.Handler, hsts bool, hosts []string) http.Handler {
+	csp := contentSecurityPolicy + "; media-src 'self' " + mediapolicy.Sources(hosts)
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		h := w.Header()
-		h.Set("Content-Security-Policy", contentSecurityPolicy+"; media-src 'self' "+mediapolicy.Sources(hosts))
+		h.Set("Content-Security-Policy", csp)
 		h.Set("X-Frame-Options", "DENY")
 		h.Set("X-Content-Type-Options", "nosniff")
 		h.Set("Referrer-Policy", "same-origin")

M internal/adapters/web/markdown.go +26 -7


@@ -39,7 +39,8 @@ const headingIDPrefix = "md-"
39	39		// protocol-relative //host, empty targets…) loses its link: the text stays;
40	40		// - video images (.mp4, .webm, .mov, .m4v, .ogv) become native players
41	41		// from the raw route or an allowlisted HTTP(S) host; other images show alt text;
42		-	// - standalone links and autolinks to allowlisted video hosts become players.
	42	+	// - standalone links and autolinks to allowlisted hosts become players only
	43	+	// for video extensions or GitHub /user-attachments/assets/<id> paths.
43	44		type markdown struct {
44	45		md goldmark.Markdown
45	46		videoHosts []string

@@ -529,12 +530,8 @@ func (p linkPolicy) videoTarget(dest string, requireExtension bool) (string, boo
529	530		if err != nil {
530	531		return "", false
531	532		}
532		-	if requireExtension {
533		-	switch strings.ToLower(path.Ext(u.Path)) {
534		-	case ".mp4", ".webm", ".mov", ".m4v", ".ogv":
535		-	default:
536		-	return "", false
537		-	}
	533	+	if requireExtension && !videoExtension(u.Path) {
	534	+	return "", false
538	535		}
539	536		p.rawVideo = true
540	537		target, kind := p.target(dest)

@@ -556,6 +553,9 @@ func (p linkPolicy) standaloneVideo(n ast.Node, dest, label string) bool {
556	553		if err != nil \|\| !mediapolicy.Allows(u, p.videoHosts) {
557	554		return false
558	555		}
	556	+	if !videoExtension(u.Path) && !githubAttachment(u) {
	557	+	return false
	558	+	}
559	559		src, ok := p.videoTarget(dest, false)
560	560		if !ok {
561	561		return false

@@ -573,3 +573,22 @@ type videoNode struct {
573	573
574	574		func (n *videoNode) Kind() ast.NodeKind { return kindVideo }
575	575		func (n *videoNode) Dump(source []byte, level int) { ast.DumpHelper(n, source, level, nil, nil) }
	576	+
	577	+	func videoExtension(name string) bool {
	578	+	switch strings.ToLower(path.Ext(name)) {
	579	+	case ".mp4", ".webm", ".mov", ".m4v", ".ogv":
	580	+	return true
	581	+	default:
	582	+	return false
	583	+	}
	584	+	}
	585	+
	586	+	// githubAttachment recognises only GitHub's extensionless attachment route,
	587	+	// not arbitrary extensionless pages on a host that also serves video files.
	588	+	func githubAttachment(u *url.URL) bool {
	589	+	if !strings.EqualFold(u.Hostname(), "github.com") {
	590	+	return false
	591	+	}
	592	+	id, ok := strings.CutPrefix(u.Path, "/user-attachments/assets/")
	593	+	return ok && id != "" && id != "." && id != ".." && !strings.Contains(id, "/") && path.Ext(id) == ""
	594	+	}

 //     protocol-relative //host, empty targets…) loses its link: the text stays;
 //   - video images (.mp4, .webm, .mov, .m4v, .ogv) become native players
 //     from the raw route or an allowlisted HTTP(S) host; other images show alt text;
-//   - standalone links and autolinks to allowlisted video hosts become players.
+//   - standalone links and autolinks to allowlisted hosts become players only
+//     for video extensions or GitHub /user-attachments/assets/<id> paths.
 type markdown struct {
 	md         goldmark.Markdown
 	videoHosts []string
 	if err != nil {
 		return "", false
 	}
-	if requireExtension {
+	if requireExtension && !videoExtension(u.Path) {
-		switch strings.ToLower(path.Ext(u.Path)) {
+		return "", false
-		case ".mp4", ".webm", ".mov", ".m4v", ".ogv":
-		default:
-			return "", false
-		}
 	}
 	p.rawVideo = true
 	target, kind := p.target(dest)
 	if err != nil || !mediapolicy.Allows(u, p.videoHosts) {
 		return false
 	}
+	if !videoExtension(u.Path) && !githubAttachment(u) {
+		return false
+	}
 	src, ok := p.videoTarget(dest, false)
 	if !ok {
 		return false
 func (n *videoNode) Kind() ast.NodeKind            { return kindVideo }
 func (n *videoNode) Dump(source []byte, level int) { ast.DumpHelper(n, source, level, nil, nil) }
+func videoExtension(name string) bool {
+	switch strings.ToLower(path.Ext(name)) {
+	case ".mp4", ".webm", ".mov", ".m4v", ".ogv":
+		return true
+	default:
+		return false
+	}
+}
+// githubAttachment recognises only GitHub's extensionless attachment route,
+// not arbitrary extensionless pages on a host that also serves video files.
+func githubAttachment(u *url.URL) bool {
+	if !strings.EqualFold(u.Hostname(), "github.com") {
+		return false
+	}
+	id, ok := strings.CutPrefix(u.Path, "/user-attachments/assets/")
+	return ok && id != "" && id != "." && id != ".." && !strings.Contains(id, "/") && path.Ext(id) == ""
+}

M internal/adapters/web/markdown_test.go +10 -0


@@ -398,6 +398,16 @@ func TestMarkdownVideos(t *testing.T) {
398	398		{"autolink", `https://github.com/user-attachments/assets/uuid`, `src="https://github.com/user-attachments/assets/uuid"`, true},
399	399		{"angle autolink", `<https://github.com/user-attachments/assets/uuid>`, `src="https://github.com/user-attachments/assets/uuid"`, true},
400	400		{"standalone link", `[clip](https://github.com/user-attachments/assets/uuid)`, `aria-label="clip"`, true},
	401	+	{"repo link", `[Source](https://github.com/org/project)`, `<a href="https://github.com/org/project"`, false},
	402	+	{"issue link", `[Issue](https://github.com/org/project/issues/123)`, `<a href="https://github.com/org/project/issues/123"`, false},
	403	+	{"root autolink", `https://github.com`, `<a href="https://github.com"`, false},
	404	+	{"root link", `[GitHub](https://github.com/)`, `<a href="https://github.com/"`, false},
	405	+	{"standalone video extension", `[clip](https://user-images.githubusercontent.com/demo.MP4?download=1)`, `<video controls`, true},
	406	+	{"video autolink", `https://github.com/demo.webm`, `<video controls`, true},
	407	+	{"attachment missing id", `https://github.com/user-attachments/assets/`, `<a href=`, false},
	408	+	{"attachment extra segment", `https://github.com/user-attachments/assets/id/extra`, `<a href=`, false},
	409	+	{"attachment nonvideo extension", `https://github.com/user-attachments/assets/id.png`, `<a href=`, false},
	410	+	{"attachment other host", `https://user-images.githubusercontent.com/user-attachments/assets/id`, `<a href=`, false},
401	411		{"inline link", `see [clip](https://github.com/user-attachments/assets/uuid) here`, `<a href=`, false},
402	412		{"blocked image", `![demo](https://evil.example/demo.mp4)`, `<span class="alt">[demo]</span>`, false},
403	413		{"blocked link", `https://evil.example/demo.mp4`, `<a href=`, false},


@@ -398,6 +398,16 @@ func TestMarkdownVideos(t *testing.T) {
398	{"autolink", `https://github.com/user-attachments/assets/uuid`, `src="https://github.com/user-attachments/assets/uuid"`, true},	398		{"autolink", `https://github.com/user-attachments/assets/uuid`, `src="https://github.com/user-attachments/assets/uuid"`, true},
399	{"angle autolink", `<https://github.com/user-attachments/assets/uuid>`, `src="https://github.com/user-attachments/assets/uuid"`, true},	399		{"angle autolink", `<https://github.com/user-attachments/assets/uuid>`, `src="https://github.com/user-attachments/assets/uuid"`, true},
400	{"standalone link", `[clip](https://github.com/user-attachments/assets/uuid)`, `aria-label="clip"`, true},	400		{"standalone link", `[clip](https://github.com/user-attachments/assets/uuid)`, `aria-label="clip"`, true},
		401	+	{"repo link", `[Source](https://github.com/org/project)`, `<a href="https://github.com/org/project"`, false},
		402	+	{"issue link", `[Issue](https://github.com/org/project/issues/123)`, `<a href="https://github.com/org/project/issues/123"`, false},
		403	+	{"root autolink", `https://github.com`, `<a href="https://github.com"`, false},
		404	+	{"root link", `[GitHub](https://github.com/)`, `<a href="https://github.com/"`, false},
		405	+	{"standalone video extension", `[clip](https://user-images.githubusercontent.com/demo.MP4?download=1)`, `<video controls`, true},
		406	+	{"video autolink", `https://github.com/demo.webm`, `<video controls`, true},
		407	+	{"attachment missing id", `https://github.com/user-attachments/assets/`, `<a href=`, false},
		408	+	{"attachment extra segment", `https://github.com/user-attachments/assets/id/extra`, `<a href=`, false},
		409	+	{"attachment nonvideo extension", `https://github.com/user-attachments/assets/id.png`, `<a href=`, false},
		410	+	{"attachment other host", `https://user-images.githubusercontent.com/user-attachments/assets/id`, `<a href=`, false},
401	{"inline link", `see [clip](https://github.com/user-attachments/assets/uuid) here`, `<a href=`, false},	411		{"inline link", `see [clip](https://github.com/user-attachments/assets/uuid) here`, `<a href=`, false},
402	{"blocked image", `![demo](https://evil.example/demo.mp4)`, `<span class="alt">[demo]</span>`, false},	412		{"blocked image", `![demo](https://evil.example/demo.mp4)`, `<span class="alt">[demo]</span>`, false},
403	{"blocked link", `https://evil.example/demo.mp4`, `<a href=`, false},	413		{"blocked link", `https://evil.example/demo.mp4`, `<a href=`, false},