nixpkgs/pkgs/build-support/cc-wrapper/add-hardening.sh
John Ericson 1ac5398589 *-wrapper; Switch from infixSalt to suffixSalt
I hate the thing too even though I made it, and rather just get rid of
it. But we can't do that yet. In the meantime, this brings us more
inline with autoconf and will make it slightly easier for me to write a
pkg-config wrapper, which we need.
2020-05-12 00:44:44 -04:00

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declare -a hardeningCFlags=()
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 ${NIX_HARDENING_ENABLE_@suffixSalt@-}; do
hardeningEnableMap["$flag"]=1
done
# Remove unsupported flags.
for flag in @hardening_unsupported_flags@; do
unset -v "hardeningEnableMap[$flag]"
done
if (( "${NIX_DEBUG:-0}" >= 1 )); then
declare -a allHardeningFlags=(fortify stackprotector pie pic strictoverflow format)
declare -A hardeningDisableMap=()
# Determine which flags were effectively disabled so we can report below.
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
if (( "${#hardeningEnableMap[@]}" )); then
echo 'HARDENING: Is active (not completely disabled with "all" flag)' >&2;
fi
fi
for flag in "${!hardeningEnableMap[@]}"; do
case $flag in
fortify)
if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling fortify >&2; fi
hardeningCFlags+=('-O2' '-D_FORTIFY_SOURCE=2')
;;
stackprotector)
if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling stackprotector >&2; fi
hardeningCFlags+=('-fstack-protector-strong' '--param' 'ssp-buffer-size=4')
;;
pie)
if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling CFlags -fPIE >&2; fi
hardeningCFlags+=('-fPIE')
if [[ ! ("$*" =~ " -shared " || "$*" =~ " -static ") ]]; then
if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling LDFlags -pie >&2; fi
hardeningCFlags+=('-pie')
fi
;;
pic)
if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling pic >&2; fi
hardeningCFlags+=('-fPIC')
;;
strictoverflow)
if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling strictoverflow >&2; fi
hardeningCFlags+=('-fno-strict-overflow')
;;
format)
if (( "${NIX_DEBUG:-0}" >= 1 )); then echo HARDENING: enabling format >&2; fi
hardeningCFlags+=('-Wformat' '-Wformat-security' '-Werror=format-security')
;;
*)
# Ignore unsupported. Checked in Nix that at least *some*
# tool supports each flag.
;;
esac
done