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nixpkgs/pkgs/build-support/bintools-wrapper/add-hardening.sh
Matthew Bauer f5074933b7
bintools: disable -pie when -r or -Ur are used (#128674)
* bintools: disable -pie when -r or -Ur are used

ld’s -r allows you to partially link object files. When -pie is passed with -r, though, we get:

  ld: -r and -pie may not be used together

Most build systems are intelligent enough to pass -no-pie before -r, but we might as well support those that
don’t.

Note: -pie is not enabled by default in Nixpkgs, but it is when you are using musl. So this solution is really
only useful for musl toolchains.

* bintools-wrapper: Add incremental -i check for pie
2021-07-15 20:08:33 -05:00

59 lines
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declare -a hardeningLDFlags=()
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=(pie relro bindnow)
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 $flag in
pie)
if [[ ! ("$*" =~ " -shared " || "$*" =~ " -static " || "$*" =~ " -r " || "$*" =~ " -Ur " || "$*" =~ " -i ") ]]; 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