CVSROOT: /cvs Module name: src Changes by: d...@cvs.openbsd.org 2012/11/02 12:18:15
Modified files: lib/libc/stdlib: malloc.3 malloc.c Log message: Add a new malloc option 'U' => "Free unmap" that does the guarding/ unmapping of freed allocations without disabling chunk randomisation like the "Freeguard" ('F') option does. Make security 'S' option use 'U' and not 'F'. Rationale: guarding with no chunk randomisation is great for debugging use-after-free, but chunk randomisation offers better defence against "heap feng shui" style attacks that depend on carefully constructing a particular heap layout so we should leave this enabled when requesting security options.