linux/scripts/test_fortify.sh
Kees Cook 818ab43fc5 fortify: Update compile-time tests for Clang 14
Clang 14 introduces support for compiletime_assert(). Update the
compile-time warning regex to catch Clang's variant of the warning text
in preparation for Clang supporting CONFIG_FORTIFY_SOURCE.

Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: linux-hardening@vger.kernel.org
Cc: llvm@lists.linux.dev
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/lkml/YfbtQKtpyAM1hHiC@dev-arch.archlinux-ax161
Signed-off-by: Kees Cook <keescook@chromium.org>
2022-02-13 16:50:06 -08:00

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#!/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"