linux/scripts/test_fortify.sh
Kees Cook be58f71037 fortify: Add compile-time FORTIFY_SOURCE tests
While the run-time testing of FORTIFY_SOURCE is already present in
LKDTM, there is no testing of the expected compile-time detections. In
preparation for correctly supporting FORTIFY_SOURCE under Clang, adding
additional FORTIFY_SOURCE defenses, and making sure FORTIFY_SOURCE
doesn't silently regress with GCC, introduce a build-time test suite that
checks each expected compile-time failure condition.

As this is relatively backwards from standard build rules in the
sense that a successful test is actually a compile _failure_, create
a wrapper script to check for the correct errors, and wire it up as
a dummy dependency to lib/string.o, collecting the results into a log
file artifact.

Signed-off-by: Kees Cook <keescook@chromium.org>
2021-10-18 12:28:52 -07:00

63 lines
1.8 KiB
Bash

#!/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 $IN"
fi
else
# If the build failed, check for the warning in the stderr (gcc).
if ! grep -q -m1 "error: call to .\b${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"