1 files changed, 72 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/build-support/cc-wrapper/add-hardening.sh b/nixpkgs/pkgs/build-support/cc-wrapper/add-hardening.sh
new file mode 100644
index 000000000000..8e2fe6c407ea
--- /dev/null
+++ b/nixpkgs/pkgs/build-support/cc-wrapper/add-hardening.sh
@@ -0,0 +1,72 @@
+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