limit allowed pattern lengths

2 files changed, 53 insertions, 116 deletions

diff --git a/common/patterns.js b/common/patterns.js
index ebb55ab..ae29fcd 100644
--- a/common/patterns.js
+++ b/common/patterns.js
@@ -5,6 +5,11 @@
  * Redistribution terms are gathered in the `copyright' file.
  */
 
+const MAX_URL_PATH_LEN = 12;
+const MAX_URL_PATH_CHARS = 255;
+const MAX_DOMAIN_LEN = 7;
+const MAX_DOMAIN_CHARS = 100;
+
 const proto_regex = /^(\w+):\/\/(.*)$/;
 
 const user_re = "[^/?#@]+@"
@@ -37,103 +42,51 @@ function deconstruct_url(url)
 	[deco.domain, deco.path, deco.query] = http_match.slice(1, 4);
     }
 
-    if (deco.domain)
-	deco.domain = deco.domain.split(".");
-
     const leading_dash = deco.path[0] === "/";
     deco.trailing_dash = deco.path[deco.path.length - 1] === "/";
-    deco.path = deco.path.split("/").filter(s => s !== "");
-    if (leading_dash || deco.path.length === 0)
-	deco.path.unshift("");
 
-    return deco;
-}
+    if (deco.domain) {
+	if (deco.domain.length > MAX_DOMAIN_CHARS) {
+	    const idx = deco.domain.indexOf(".", deco.domain.length -
+					    MAX_DOMAIN_CHARS);
+	    if (idx === -1)
+		deco.domain = [];
+	    else
+		deco.domain = deco.domain.substring(idx + 1);
 
-/* Be sane: both arguments should be arrays of length >= 2 */
-function domain_matches(url_domain, pattern_domain)
-{
-    const length_difference = url_domain.length - pattern_domain.length;
-
-    for (let i = 1; i <= url_domain.length; i++) {
-	const url_part = url_domain[url_domain.length - i];
-	const pattern_part = pattern_domain[pattern_domain.length - i];
-
-	if (pattern_domain.length === i) {
-	    if (pattern_part === "*")
-		return length_difference === 0;
-	    if (pattern_part === "**")
-		return length_difference > 0;
-	    if (pattern_part === "***")
-		return true;
-	    return length_difference === 0 && pattern_part === url_part;
+	    deco.domain_truncated = true;
 	}
 
-	if (pattern_part !== url_part)
-	    return false;
-    }
-
-    return pattern_domain.length === url_domain.length + 1 &&
-	pattern_domain[0] === "***";
-}
-
-function path_matches(url_path, url_trailing_dash,
-		      pattern_path, pattern_trailing_dash)
-{
-    const dashes_ok = !(pattern_trailing_dash && !url_trailing_dash);
-
-    if (pattern_path.length === 0)
-	return url_path.length === 0 && dashes_ok;
-
-    const length_difference = url_path.length - pattern_path.length;
-
-    for (let i = 0; i < url_path.length; i++) {
-	if (pattern_path.length === i + 1) {
-	    if (pattern_path[i] === "*")
-		return length_difference === 0;
-	    if (pattern_path[i] === "**") {
-		return length_difference > 0 ||
-		    (url_path[i] === "**" && dashes_ok);
-	    }
-	    if (pattern_path[i] === "***")
-		return length_difference >= 0;
-	    return length_difference === 0 &&
-		pattern_path[i] === url_path[i] && dashes_ok;
+	if (deco.path.length > MAX_URL_PATH_CHARS) {
+	    deco.path = deco.path.substring(0, deco.path.lastIndexOf("/"));
+	    deco.path_truncated = true;
 	}
-
-	if (pattern_path[i] !== url_path[i])
-	    return false;
     }
 
-    return false;
-}
-
-function url_matches(url, pattern)
-{
-    const url_deco = deconstruct_url(url);
-    const pattern_deco = deconstruct_url(pattern);
-
-    if (url_deco === undefined || pattern_deco === undefined) {
-	console.log(`bad comparison: ${url} and ${pattern}`);
-	return false
+    if (typeof deco.domain === "string") {
+	deco.domain = deco.domain.split(".");
+	if (deco.domain.splice(0, deco.domain.length - MAX_DOMAIN_LEN).length
+	    > 0)
+	    deco.domain_truncated = true;
     }
 
-    return pattern_deco.proto === url_deco.proto &&
-	!(pattern_deco.proto === "file" && pattern_deco.trailing_dash) &&
-	!!url_deco.domain === !!pattern_deco.domain &&
-	(!url_deco.domain ||
-	 domain_matches(url_deco.domain, pattern_deco.domain)) &&
-	path_matches(url_deco.path, url_deco.trailing_dash,
-		     pattern_deco.path, pattern_deco.trailing_dash);
+    deco.path = deco.path.split("/").filter(s => s !== "");
+    if (deco.domain && deco.path.splice(MAX_URL_PATH_LEN).length > 0)
+	deco.path_truncated = true;
+    if (leading_dash || deco.path.length === 0)
+	deco.path.unshift("");
+
+    return deco;
 }
 
-function* each_domain_pattern(domain_segments)
+function* each_domain_pattern(deco)
 {
-    for (let slice = 0; slice < domain_segments.length; slice++) {
-	const domain_part = domain_segments.slice(slice).join(".");
+    for (let slice = 0; slice < deco.domain.length - 1; slice++) {
+	const domain_part = deco.domain.slice(slice).join(".");
 	const domain_wildcards = [];
-	if (slice === 0)
+	if (slice === 0 && !deco.domain_truncated)
 	    yield domain_part;
-	if (slice === 1)
+	if (slice === 1 && !deco.domain_truncated)
 	    yield "*." + domain_part;
 	if (slice > 1)
 	    yield "**." + domain_part;
@@ -141,22 +94,23 @@ function* each_domain_pattern(domain_segments)
     }
 }
 
-function* each_path_pattern(path_segments, trailing_dash)
+function* each_path_pattern(deco)
 {
-    for (let slice = path_segments.length; slice > 0; slice--) {
-	const path_part = path_segments.slice(0, slice).join("/");
+    for (let slice = deco.path.length; slice > 0; slice--) {
+	const path_part = deco.path.slice(0, slice).join("/");
 	const path_wildcards = [];
-	if (slice === path_segments.length) {
-	    if (trailing_dash)
+	if (slice === deco.path.length && !deco.path_truncated) {
+	    if (deco.trailing_dash)
 		yield path_part + "/";
 	    yield path_part;
 	}
-	if (slice === path_segments.length - 1 && path_segments[slice] !== "*")
+	if (slice === deco.path.length - 1 && !deco.path_truncated &&
+	    deco.path[slice] !== "*")
 	    yield path_part + "/*";
-	if (slice < path_segments.length - 1)
+	if (slice < deco.path.length - 1)
 	    yield path_part + "/**";
-	if (slice < path_segments.length - 1 ||
-	    path_segments[path_segments.length - 1] !== "***")
+	if (slice !== deco.path.length - 1 || deco.path_truncated ||
+	    deco.path[slice] !== "***")
 	    yield path_part + "/***";
     }
 }
@@ -167,20 +121,19 @@ function* each_url_pattern(url)
     const deco = deconstruct_url(url);
 
     if (deco === undefined) {
-	console.log("bad url format", url);
+	console.error("bad url format", url);
 	return false;
     }
 
-    const all_domains = deco.domain ? each_domain_pattern(deco.domain) : [""];
+    const all_domains = deco.domain ? each_domain_pattern(deco) : [""];
     for (const domain of all_domains) {
-	for (const path of each_path_pattern(deco.path, deco.trailing_dash))
+	for (const path of each_path_pattern(deco))
 	    yield `${deco.proto}://${domain}${path}`;
     }
 }
 
 /*
  * EXPORTS_START
- * EXPORT url_matches
  * EXPORT each_url_pattern
  * EXPORTS_END
  */
diff --git a/html/display-panel.js b/html/display-panel.js
index 623ff36..84c922f 100644
--- a/html/display-panel.js
+++ b/html/display-panel.js
@@ -21,7 +21,6 @@
  * IMPORT TYPE_PREFIX
  * IMPORT nice_name
  * IMPORT open_in_settings
- * IMPORT url_matches
  * IMPORT each_url_pattern
  * IMPORT by_id
  * IMPORT clone_template
@@ -114,36 +113,21 @@ function add_pattern_to_list(pattern)
     return template;
 }
 
-function ensure_pattern_exists(pattern)
-{
-    let entry_object = known_patterns.get(pattern);
-    /*
-     * As long as pattern computation works well, we should never get into this
-     * conditional block. This is just a safety measure. To be removed as part
-     * of a bigger rework when we start taking iframes into account.
-     */
-    if (entry_object === undefined) {
-	console.log(`unknown pattern: ${pattern}`);
-	entry_object = add_pattern_to_list(pattern);
-    }
-
-    return entry_object;
-}
-
 function style_possible_pattern_entry(pattern, exists_in_settings)
 {
     const [text, class_action] = exists_in_settings ?
 	  ["Edit", "add"] : ["Add", "remove"];
-    const entry_object = ensure_pattern_exists(pattern);
+    const entry_object = known_patterns.get(pattern);
 
-    entry_object.button.textContent = `${text} setting`;
-    entry_object.entry.classList[class_action]("matched_pattern");
+    if (entry_object) {
+	entry_object.button.textContent = `${text} setting`;
+	entry_object.entry.classList[class_action]("matched_pattern");
+    }
 }
 
 function handle_page_change(change)
 {
-    if (url_matches(tab_url, change.item))
-        style_possible_pattern_entry(change.item, change.new_val !== undefined);
+    style_possible_pattern_entry(change.item, change.new_val !== undefined);
 }
 
 function populate_possible_patterns_list(url)