Subject: bug#27838: grep error: "regexec.c:1375: pop_fail_stack: Assertion `num >= 0' failed."

From: Jacek Wielemborek <[email-masked]>
Date: Wed, 26 Jul 2017 16:53:07 +0200

Hi,

Try out the following test case, IIRC found with the aid of afl-fuzz:

grep -E -f <( echo
'fzJ7fymOjgqOjgkfMnt/KSgfVzN8pFyQKR8zfGR7pGuQKR8zfCh8Mnt/KSgfVzN8pFyQKR8zfGR7pGuQKR8zfGR7kCkoCx8zfDJ7fymOrQmOjgkfM3wkXDI='
| base64 -d ) /dev/null
grep: regexec.c:1375: pop_fail_stack: Assertion `num >= 0' failed.

I reported it once as on Fedora's Bugzilla, but got no reaction - in
that case it even triggered a segmentation fault.

Cheers,
d33tah