fortify: move test_fortify.sh to lib/test_fortify/

This script is only used in lib/test_fortify/.

There is no reason to keep it in scripts/.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20240727150302.1823750-3-masahiroy@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>

2 files changed, 68 insertions, 2 deletions

diff --git a/lib/test_fortify/Makefile b/lib/test_fortify/Makefile
index 3907a2242ef9..1826172c32d4 100644
--- a/lib/test_fortify/Makefile
+++ b/lib/test_fortify/Makefile
@@ -3,10 +3,10 @@
 ccflags-y := $(call cc-disable-warning,fortify-source)
 
 quiet_cmd_test_fortify = TEST    $@
-      cmd_test_fortify = $(CONFIG_SHELL) $(srctree)/scripts/test_fortify.sh \
+      cmd_test_fortify = $(CONFIG_SHELL) $(src)/test_fortify.sh \
 			$< $@ "$(NM)" $(CC) $(c_flags) -DKBUILD_EXTRA_WARN1
 
-$(obj)/%.log: $(src)/%.c $(srctree)/scripts/test_fortify.sh \
+$(obj)/%.log: $(src)/%.c $(src)/test_fortify.sh \
 	      $(src)/test_fortify.h \
 	      $(srctree)/include/linux/fortify-string.h \
 	      FORCE
diff --git a/lib/test_fortify/test_fortify.sh b/lib/test_fortify/test_fortify.sh
new file mode 100644
index 000000000000..c2688ab8281d
--- /dev/null
+++ b/lib/test_fortify/test_fortify.sh
@@ -0,0 +1,66 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+set -e
+
+# Argument 1: Source file to build.
+IN="$1"
+shift
+# Extract just the filename for error messages below.
+FILE="${IN##*/}"
+# Extract the function name for error messages below.
+FUNC="${FILE#*-}"
+FUNC="${FUNC%%-*}"
+FUNC="${FUNC%%.*}"
+# Extract the symbol to test for in build/symbol test below.
+WANT="__${FILE%%-*}"
+
+# Argument 2: Where to write the build log.
+OUT="$1"
+shift
+TMP="${OUT}.tmp"
+
+# Argument 3: Path to "nm" tool.
+NM="$1"
+shift
+
+# Remaining arguments are: $(CC) $(c_flags)
+
+# Clean up temporary file at exit.
+__cleanup() {
+	rm -f "$TMP"
+}
+trap __cleanup EXIT
+
+# Function names in warnings are wrapped in backticks under UTF-8 locales.
+# Run the commands with LANG=C so that grep output will not change.
+export LANG=C
+
+status=
+# Attempt to build a source that is expected to fail with a specific warning.
+if "$@" -Werror -c "$IN" -o "$OUT".o 2> "$TMP" ; then
+	# If the build succeeds, either the test has failed or the
+	# warning may only happen at link time (Clang). In that case,
+	# make sure the expected symbol is unresolved in the symbol list.
+	# If so, FORTIFY is working for this case.
+	if ! $NM -A "$OUT".o | grep -m1 "\bU ${WANT}$" >>"$TMP" ; then
+		status="warning: unsafe ${FUNC}() usage lacked '$WANT' symbol in $IN"
+	fi
+else
+	# If the build failed, check for the warning in the stderr.
+	# GCC:
+	# ./include/linux/fortify-string.h:316:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
+	# Clang 14:
+	# ./include/linux/fortify-string.h:316:4: error: call to __write_overflow_field declared with 'warning' attribute: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror,-Wattribute-warning]
+	if ! grep -Eq -m1 "error: call to .?\b${WANT}\b.?" "$TMP" ; then
+		status="warning: unsafe ${FUNC}() usage lacked '$WANT' warning in $IN"
+	fi
+fi
+
+if [ -n "$status" ]; then
+	# Report on failure results, including compilation warnings.
+	echo "$status" | tee "$OUT" >&2
+else
+	# Report on good results, and save any compilation output to log.
+	echo "ok: unsafe ${FUNC}() usage correctly detected with '$WANT' in $IN" >"$OUT"
+fi
+cat "$TMP" >>"$OUT"