nixpkgs/pkgs/build-support/cc-wrapper/add-hardening.sh
John Ericson 97a48835b7 mkDerivation, cc-wrapper: Check hardening flag validity in Nix
This becomes necessary if more wrappers besides cc-wrapper start
supporting hardening flags. Also good to make the warning into an
error.

Also ensure interface is being used right: Not as a string, not just in
bash.
2017-08-30 17:53:42 +02:00

78 lines
2.8 KiB
Bash

hardeningFlags=(fortify stackprotector pic strictoverflow format relro bindnow)
# Intentionally word-split in case 'hardeningEnable' is defined in
# Nix. Also, our bootstrap tools version of bash is old enough that
# undefined arrays trip `set -u`.
if [[ -v hardeningEnable[@] ]]; then
hardeningFlags+=(${hardeningEnable[@]})
fi
hardeningCFlags=()
hardeningLDFlags=()
declare -A hardeningDisableMap
# Intentionally word-split in case 'hardeningDisable' is defined in Nix.
for flag in ${hardeningDisable[@]:-IGNORED_KEY} @hardening_unsupported_flags@
do
hardeningDisableMap[$flag]=1
done
if [[ -n "${NIX_DEBUG:-}" ]]; then
printf 'HARDENING: disabled flags:' >&2
(( "${#hardeningDisableMap[@]}" )) && printf ' %q' "${!hardeningDisableMap[@]}" >&2
echo >&2
fi
if [[ -z "${hardeningDisableMap[all]:-}" ]]; then
if [[ -n "${NIX_DEBUG:-}" ]]; then
echo 'HARDENING: Is active (not completely disabled with "all" flag)' >&2;
fi
for flag in "${hardeningFlags[@]}"
do
if [[ -z "${hardeningDisableMap[$flag]:-}" ]]; then
case $flag in
fortify)
if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling fortify >&2; fi
hardeningCFlags+=('-O2' '-D_FORTIFY_SOURCE=2')
;;
stackprotector)
if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling stackprotector >&2; fi
hardeningCFlags+=('-fstack-protector-strong' '--param' 'ssp-buffer-size=4')
;;
pie)
if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling CFlags -fPIE >&2; fi
hardeningCFlags+=('-fPIE')
if [[ ! ("$*" =~ " -shared " || "$*" =~ " -static ") ]]; then
if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling LDFlags -pie >&2; fi
hardeningCFlags+=('-pie')
hardeningLDFlags+=('-pie')
fi
;;
pic)
if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling pic >&2; fi
hardeningCFlags+=('-fPIC')
;;
strictoverflow)
if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling strictoverflow >&2; fi
hardeningCFlags+=('-fno-strict-overflow')
;;
format)
if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling format >&2; fi
hardeningCFlags+=('-Wformat' '-Wformat-security' '-Werror=format-security')
;;
relro)
if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling relro >&2; fi
hardeningLDFlags+=('-z' 'relro')
;;
bindnow)
if [[ -n "${NIX_DEBUG:-}" ]]; then echo HARDENING: enabling bindnow >&2; fi
hardeningLDFlags+=('-z' 'now')
;;
*)
# Ignore unsupported. Checked in Nix that at least *some*
# tool supports each flag.
;;
esac
fi
done
fi