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author | Kees Cook <keescook@chromium.org> | 2021-04-21 09:22:52 +0300 |
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committer | Kees Cook <keescook@chromium.org> | 2021-10-18 22:28:52 +0300 |
commit | be58f7103700a68d5c7ca60a2bc0b309907599ab (patch) | |
tree | d9caaca50a2c98c6458372fac636bee254b1da9e /scripts/test_fortify.sh | |
parent | 3009f891bb9f328945ebd5b71e12df7e2467f3dd (diff) | |
download | linux-be58f7103700a68d5c7ca60a2bc0b309907599ab.tar.xz |
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>
Diffstat (limited to 'scripts/test_fortify.sh')
-rw-r--r-- | scripts/test_fortify.sh | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/scripts/test_fortify.sh b/scripts/test_fortify.sh new file mode 100644 index 000000000000..a4da365508f0 --- /dev/null +++ b/scripts/test_fortify.sh @@ -0,0 +1,62 @@ +#!/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" |