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Potential fix for code scanning alert no. 56: Client-side URL redirect #26

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Merged
paule32 merged 1 commit into from
Oct 28, 2025
Merged

Potential fix for code scanning alert no. 56: Client-side URL redirect #26

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13 changes: 12 additions & 1 deletion src/doc/files/js/chmRelative.js
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Original file line number Diff line number Diff line change
@@ -1 +1,12 @@
function relativelnk(a){var b,c;b=location.href.search(/:/)==2?14:7;c=location.href.lastIndexOf("\\")+1;a="file:///"+location.href.substring(b,c)+a;location.href=a};
function relativelnk(a){
// Simple path validation: allow only relative filenames (no slashes, no colon, no protocol)
if (typeof a !== 'string' || a.match(/^[a-zA-Z0-9_.-]+$/) === null) {
console.error('Invalid path for redirect');
return;
}
var b, c;
b = location.href.search(/:/)==2 ? 14 : 7;
c = location.href.lastIndexOf("\\")+1;
a = "file:///" + location.href.substring(b, c) + a;
location.href = a;

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Code scanning / CodeQL

Client-side URL redirect Medium documentation

Untrusted URL redirection depends on a
user-provided value
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Copilot Autofix

AI 5 months ago

To fix the client-side URL redirect issue, we should sanitize and strictly validate all parts that contribute to the redirect URL. In particular, we should avoid using unchecked data from location.href to construct file paths, and instead use a safer mechanism. Since the function intends to redirect to a locally available help file referenced by a filename, it should select from a hardcoded list of allowed filenames or simply use the provided parameter a as a relative filename, not concatenated with user-controlled path data. If directory navigation is needed, define an allowed set of directories (preferably hardcoded), and ignore any values derived from the current location. This prevents attackers from manipulating the redirect path via location.

Therefore, the best way to fix the problem is to keep the allowed filenames in a white-list array, verify a is in that array, and construct the redirect path only from trusted base directory + safe filename, avoiding the use of location.href for redirect destination construction.

Edits needed: In src/doc/files/js/chmRelative.js, update the implementation of relativelnk such that:

  • A hardcoded base directory is used (for local help files, e.g., file:///C:/Program Files/HelpFiles/).
  • The function checks that a is in a whitelist of allowed filenames.
  • Only construct the redirect URL from trusted parts, completely avoiding use of location.href for redirect destination.
    The whitelist should be declared in the same file.
Suggested changeset 1
src/doc/files/js/chmRelative.js

Autofix patch

Autofix patch
Run the following command in your local git repository to apply this patch
cat << 'EOF' | git apply
diff --git a/src/doc/files/js/chmRelative.js b/src/doc/files/js/chmRelative.js
--- a/src/doc/files/js/chmRelative.js
+++ b/src/doc/files/js/chmRelative.js
@@ -1,12 +1,20 @@
+// Whitelist of allowed help file names (add entries as needed)
+const allowedHelpFiles = [
+    "index.html",
+    "getting_started.html",
+    "faq.html",
+    "installation.html",
+    "advanced_topics.html"
+];
+
 function relativelnk(a){
-    // Simple path validation: allow only relative filenames (no slashes, no colon, no protocol)
-    if (typeof a !== 'string' || a.match(/^[a-zA-Z0-9_.-]+$/) === null) {
-        console.error('Invalid path for redirect');
+    // Only allow a to be from the whitelist of help files
+    if (typeof a !== 'string' || !allowedHelpFiles.includes(a)) {
+        console.error('Invalid or unauthorized help file requested; aborting redirect.');
         return;
     }
-    var b, c;
-    b = location.href.search(/:/)==2 ? 14 : 7;
-    c = location.href.lastIndexOf("\\")+1;
-   a = "file:///" + location.href.substring(b, c) + a;
-   location.href = a;
+    // Use a fixed trusted help files directory
+    var baseHelpPath = "file:///C:/Program Files/HelpFiles/";
+    var targetURL = baseHelpPath + a;
+    location.href = targetURL;
 };
\ No newline at end of file
EOF
@@ -1,12 +1,20 @@
// Whitelist of allowed help file names (add entries as needed)
const allowedHelpFiles = [
"index.html",
"getting_started.html",
"faq.html",
"installation.html",
"advanced_topics.html"
];

function relativelnk(a){
// Simple path validation: allow only relative filenames (no slashes, no colon, no protocol)
if (typeof a !== 'string' || a.match(/^[a-zA-Z0-9_.-]+$/) === null) {
console.error('Invalid path for redirect');
// Only allow a to be from the whitelist of help files
if (typeof a !== 'string' || !allowedHelpFiles.includes(a)) {
console.error('Invalid or unauthorized help file requested; aborting redirect.');
return;
}
var b, c;
b = location.href.search(/:/)==2 ? 14 : 7;
c = location.href.lastIndexOf("\\")+1;
a = "file:///" + location.href.substring(b, c) + a;
location.href = a;
// Use a fixed trusted help files directory
var baseHelpPath = "file:///C:/Program Files/HelpFiles/";
var targetURL = baseHelpPath + a;
location.href = targetURL;
};
Copilot is powered by AI and may make mistakes. Always verify output.
};
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