MGASA-2017-0184

The sunrpc implementation in glibc is vulnerable to a flaw that can cause it to be triggered to allocate additional memory until it causes a crash, similar to CVE-2017-8779 (CVE-2017-8804).

A flaw was found in the way memory was being allocated on the stack for user space binaries. If heap (or different memory region) and stack memory regions were adjacent to each other, an attacker could use this flaw to jump over the stack guard gap, cause controlled memory corruption on process stack or the adjacent memory region, and thus increase their privileges on the system. This is glibc-side mitigation which blocks processing of LDLIBRARYPATH for programs running in secure-execution mode and reduces the number of allocations performed by the processing of LDAUDIT, LDPRELOAD, and LDHWCAPMASK, making successful exploitation of this issue more difficult (CVE-2017-1000366).

The CVE-2017-1000366 issue is part of a set of issues known as Stack Clash. The fixes have components in both glibc and the kernel. The kernel fix will be included in a separate update advisory (mga#21141)