From 38066a2195c8cb4d630db9016b7fdce88cb9dfbb Mon Sep 17 00:00:00 2001
From: Jinwoo-H <jinwoo0825@gmail.com>
Date: Sat, 30 May 2026 04:47:24 -0700
Subject: [PATCH] Tighten repo icon href filtering

Co-authored-by: Orca <help@stably.ai>
---
 src/main/repo-icon-autodetect.test.ts | 24 ++++++++++++++++++++++++
 src/main/repo-icon-autodetect.ts      | 27 ++++++++++++++-------------
 2 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/src/main/repo-icon-autodetect.test.ts b/src/main/repo-icon-autodetect.test.ts
index 356fb48294c..5003f08d94b 100644
--- a/src/main/repo-icon-autodetect.test.ts
+++ b/src/main/repo-icon-autodetect.test.ts
@@ -88,6 +88,30 @@ describe('detectRepoIcon', () => {
     })
   })
 
+  it('does not reinterpret URL-like icon hrefs as repo-local paths', async () => {
+    const repoPath = await makeTempRepoDir()
+    await mkdir(join(repoPath, 'public', 'https:', 'cdn.example.com'), { recursive: true })
+    await writeFile(
+      join(repoPath, 'index.html'),
+      '<link rel="icon" href="https://cdn.example.com/icon.png">'
+    )
+    await writeFile(
+      join(repoPath, 'public', 'https:', 'cdn.example.com', 'icon.png'),
+      Buffer.from(PNG_1X1_BASE64, 'base64')
+    )
+    await writeFile(
+      join(repoPath, 'package.json'),
+      JSON.stringify({ homepage: 'https://app.example.com/docs' })
+    )
+
+    await expect(detectRepoIcon({ repoPath, kind: 'folder' })).resolves.toEqual({
+      type: 'image',
+      src: 'https://www.google.com/s2/favicons?domain=app.example.com&sz=64',
+      source: 'favicon',
+      label: 'Website favicon'
+    })
+  })
+
   it('falls back to the GitHub owner avatar for GitHub repos', async () => {
     const repoPath = await makeTempRepoDir()
     await gitExecFileAsync(['init'], { cwd: repoPath })
diff --git a/src/main/repo-icon-autodetect.ts b/src/main/repo-icon-autodetect.ts
index c5d6a1f50c9..cc389e828b1 100644
--- a/src/main/repo-icon-autodetect.ts
+++ b/src/main/repo-icon-autodetect.ts
@@ -75,17 +75,18 @@ function extractIconHref(source: string): string | null {
   return source.match(LINK_ICON_HTML_RE)?.[1] ?? source.match(LINK_ICON_OBJECT_RE)?.[1] ?? null
 }
 
-function normalizeIconRelativePath(relativePath: string): string | null {
-  const normalized = relativePath.replace(/\\/g, '/').trim()
+function normalizeIconHrefPath(href: string): string | null {
+  const normalized = href.replace(/\\/g, '/').trim()
   if (
     !normalized ||
-    normalized.startsWith('/') ||
     normalized.includes('\0') ||
+    normalized.startsWith('//') ||
     /^[A-Za-z][A-Za-z0-9+.-]*:/.test(normalized)
   ) {
     return null
   }
-  const segments = normalized.split('/').filter((segment) => segment && segment !== '.')
+  const rootRelativePath = normalized.replace(/^\/+/, '')
+  const segments = rootRelativePath.split('/').filter((segment) => segment && segment !== '.')
   if (segments.length === 0 || segments.some((segment) => segment === '..')) {
     return null
   }
@@ -93,15 +94,15 @@ function normalizeIconRelativePath(relativePath: string): string | null {
 }
 
 function iconHrefCandidates(href: string): string[] {
-  const clean = href.replace(/^\/+/, '')
-  const candidates: string[] = []
-  for (const candidate of [`public/${clean}`, clean]) {
-    // Why: icon hrefs are repo-controlled input; never let detection probe above
-    // the selected repo root while looking for a best-effort visual.
-    const normalized = normalizeIconRelativePath(candidate)
-    if (normalized && !candidates.includes(normalized)) {
-      candidates.push(normalized)
-    }
+  // Why: icon hrefs are repo-controlled input; reject unsafe shapes before
+  // adding repo-local lookup prefixes so URL-like hrefs cannot be reinterpreted.
+  const clean = normalizeIconHrefPath(href)
+  if (!clean) {
+    return []
+  }
+  const candidates = [`public/${clean}`, clean]
+  if (candidates[0] === candidates[1]) {
+    return [candidates[0]]
   }
   return candidates
 }