nixpkgs/pkgs/build-support/bintools-wrapper/add-hardening.sh
2018-04-10 15:27:13 -04:00

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hardeningFlags=()
declare -A hardeningEnableMap=()
# Intentionally word-split in case 'NIX_HARDENING_ENABLE' is defined in Nix. The
# array expansion also prevents undefined variables from causing trouble with
# `set -u`.
for flag in ${NIX_@infixSalt@_HARDENING_ENABLE-}; do
hardeningEnableMap[$flag]=1
done
# Remove unsupported flags.
for flag in @hardening_unsupported_flags@; do
unset hardeningEnableMap[$flag]
done
if (( "${NIX_DEBUG:-0}" >= 1 )); then
# Determine which flags were effectively disabled so we can report below.
allHardeningFlags=(pie relro bindnow)
declare -A hardeningDisableMap=()
for flag in ${allHardeningFlags[@]}; do
if [[ -z "${hardeningEnableMap[$flag]-}" ]]; then
hardeningDisableMap[$flag]=1
fi
done
printf 'HARDENING: disabled flags:' >&2
(( "${#hardeningDisableMap[@]}" )) && printf ' %q' "${!hardeningDisableMap[@]}" >&2
echo >&2
fi
if (( "${#hardeningEnableMap[@]}" )); then
if (( "${NIX_DEBUG:-0}" >= 1 )); then
echo 'HARDENING: Is active (not completely disabled with "all" flag)' >&2;
fi
for flag in "${!hardeningEnableMap[@]}"; do
case $flag in
pie)
if [[ ! ("$*" =~ " -shared " || "$*" =~ " -static ") ]]; then
if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling LDFlags -pie >&2; fi
hardeningLDFlags+=('-pie')
fi
;;
relro)
if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling relro >&2; fi
hardeningLDFlags+=('-z' 'relro')
;;
bindnow)
if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling bindnow >&2; fi
hardeningLDFlags+=('-z' 'now')
;;
*)
# Ignore unsupported. Checked in Nix that at least *some*
# tool supports each flag.
;;
esac
done
fi