An install reported a segfault which I traced to this regex in a Herald rule:
I think this simplifies to /^(.)*$/, which captures every character, although I'm not certain that's enough to cause backtracking/recursion on its own.
I avoided this by changing pcre.backtrack_limit and pcre.recursion_limit to 10000. I expect to deploy some flavor of this as a configuration change to the cluster.
- What are reasonable limits?
- What's a test case for hitting the backtrace limit? The recursion limit?
- How can we distinguish between hitting the backtrack/recursion limit and other failures? Does preg_match() just return false nicely?