Fix crash in linkify inline rule on malformed input

CHANGELOG.md

@@ -6,10 +6,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
-## [13.1.0] - WIP
-### Changed
+## [13.0.2] - WIP
+### Fixed
 - Throw an error if 3rd party plugin doesn't increment `line` or `pos` counters
   (previously, markdown-it would likely go into infinite loop instead), #847.
+- Fixed crash/infinite loop caused by linkify inline rule, #957.
 
 ## [13.0.1] - 2022-05-03
 ### Fixed
@@ -621,7 +622,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Renamed presets folder (configs -> presets).
 
 
-[13.1.0]: https://github.com/markdown-it/markdown-it/compare/13.0.1...13.1.0
+[13.0.2]: https://github.com/markdown-it/markdown-it/compare/13.0.1...13.0.2
 [13.0.1]: https://github.com/markdown-it/markdown-it/compare/13.0.0...13.0.1
 [13.0.0]: https://github.com/markdown-it/markdown-it/compare/12.3.2...13.0.0
 [12.3.2]: https://github.com/markdown-it/markdown-it/compare/12.3.1...12.3.2

lib/rules_inline/linkify.js

@@ -31,6 +31,10 @@ module.exports = function linkify(state, silent) {
 
   url = link.url;
 
+  // invalid link, but still detected by linkify somehow;
+  // need to check to prevent infinite loop below
+  if (url.length <= proto.length) return false;
+
   // disallow '*' at the end of the link (conflicts with emphasis)
   url = url.replace(/\*+$/, '');
 

test/fixtures/markdown-it/linkify.txt

@@ -167,3 +167,10 @@ https://www.sell.fi/sites/default/files/elainlaakarilehti/tieteelliset_artikkeli
 .
 <p><a href="https://www.sell.fi/sites/default/files/elainlaakarilehti/tieteelliset_artikkelit/kahkonen_t._et_al.canine_pancreatitis-_review.pdf">https://www.sell.fi/sites/default/files/elainlaakarilehti/tieteelliset_artikkelit/kahkonen_t._et_al.canine_pancreatitis-_review.pdf</a></p>
 .
+
+regression test, invalid link:
+.
+i.org[x[x][xx: htt://a.b://a
+.
+<p><a href="http://i.org">i.org</a>[x[x][xx: htt://a.b://a</p>
+.