The OpenBSD qsort() function is recursive, and not randomized, an...

Vulnerability Description

The OpenBSD qsort() function is recursive, and not randomized, an attacker can construct a pathological input array of N elements that causes qsort() to deterministically recurse N/4 times. This allows attackers to consume arbitrary amounts of stack memory and manipulate stack memory to assist in arbitrary code execution attacks. This affects OpenBSD 6.1 and possibly earlier versions.

References

• https://www.exploit-db.com/exploits/42271/
• https://support.apple.com/HT208144
• https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt
• https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/lib/libc/stdlib/qsort.c?rev=1.15&content-type=text/x-cvsweb-markup
• http://www.securityfocus.com/bid/99177
• http://www.securitytracker.com/id/1039427
• https://support.apple.com/HT208113
• https://support.apple.com/HT208112
• https://support.apple.com/HT208115