https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt The advisory suggests: 1. Increase the size of the stack guard-page to at least 1MB - I skip this point 2. Recompile all userland code with GCC's "-fstack-check" option - I checked current and recent gcc versions.
6.3.0 seems to be fine: gcc version 6.3.0 (Gentoo Hardened 6.3.0 p1.0) gcc -dumpspecs | grep -B 1 stack-check *cc1: %{!mandroid|tno-android-cc:%(cc1_cpu) %{profile:-p};:%(cc1_cpu) %{profile:-p} %{!mglibc:%{!muclibc:%{!mbionic: -mbionic}}} %{!fno-pic:%{!fno-PIC:%{!fpic:%{!fPIC: -fPIC}}}}}%{fstack-check|fstack-check=*:;: -fstack-check} 5.4.0 also looks fine: gcc version 5.4.0 (Gentoo Hardened 5.4.0-r3 p1.3, pie-0.6.5) gcc -dumpspecs | grep -B 1 stack-check *esp_cc1_ssp: %{!fno-stack-protector: %{!fno-stack-protector-all: %{!fno-stack-check: }}} -- *esp_options_ssp: %{nostdlib|ffreestanding|fno-stack-protector|fstack-protector| fstack-protector-all|fstack-protector-strong:;:-fstack-protector-all} %{fstack-check|fstack-check=*:;: -fstack-check} I assume it is OK like this. Please confirm this conclusion. Thx: Dw. -- dr Tóth Attila, Radiológus, 06-20-825-8057 Attila Toth MD, Radiologist, +36-20-825-8057