1 files changed, 81 insertions, 0 deletions
diff --git a/scripts/build-fuzzers.sh b/scripts/build-fuzzers.sh
new file mode 100755
index 0000000..a704f47
--- /dev/null
+++ b/scripts/build-fuzzers.sh
@@ -0,0 +1,81 @@
+#!/bin/bash
+set -eux
+
+SANITIZER=${SANITIZER:-address}
+flags="-O1 -fno-omit-frame-pointer -g -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -fsanitize=$SANITIZER -fsanitize=fuzzer-no-link"
+
+export CC=${CC:-clang}
+export CFLAGS=${CFLAGS:-$flags}
+
+export CXX=${CXX:-clang++}
+export CXXFLAGS=${CXXFLAGS:-$flags}
+
+cd "$(dirname -- "$0")/.."
+
+export OUT=${OUT:-"$(pwd)/out"}
+mkdir -p "$OUT"
+
+export LIB_FUZZING_ENGINE=${LIB_FUZZING_ENGINE:--fsanitize=fuzzer}
+
+# libelf is compiled with _FORTIFY_SOURCE by default and it
+# isn't compatible with MSan. It was borrowed
+# from https://github.com/google/oss-fuzz/pull/7422
+if [[ "$SANITIZER" == memory ]]; then
+    CFLAGS+=" -U_FORTIFY_SOURCE"
+    CXXFLAGS+=" -U_FORTIFY_SOURCE"
+fi
+
+# The alignment check is turned off by default on OSS-Fuzz/CFLite so it should be
+# turned on explicitly there. It was borrowed from
+# https://github.com/google/oss-fuzz/pull/7092
+if [[ "$SANITIZER" == undefined ]]; then
+    additional_ubsan_checks=alignment
+    UBSAN_FLAGS="-fsanitize=$additional_ubsan_checks -fno-sanitize-recover=$additional_ubsan_checks"
+    CFLAGS+=" $UBSAN_FLAGS"
+    CXXFLAGS+=" $UBSAN_FLAGS"
+fi
+
+# Ideally libbelf should be built using release tarballs available
+# at https://sourceware.org/elfutils/ftp/. Unfortunately sometimes they
+# fail to compile (for example, elfutils-0.185 fails to compile with LDFLAGS enabled
+# due to https://bugs.gentoo.org/794601) so let's just point the script to
+# commits referring to versions of libelf that actually can be built
+rm -rf elfutils
+git clone git://sourceware.org/git/elfutils.git
+(
+cd elfutils
+git checkout e9f3045caa5c4498f371383e5519151942d48b6d
+git log --oneline -1
+
+# ASan isn't compatible with -Wl,--no-undefined: https://github.com/google/sanitizers/issues/380
+find -name Makefile.am | xargs sed -i 's/,--no-undefined//'
+
+# ASan isn't compatible with -Wl,-z,defs either:
+# https://clang.llvm.org/docs/AddressSanitizer.html#usage
+sed -i 's/^\(ZDEFS_LDFLAGS=\).*/\1/' configure.ac
+
+if [[ "$SANITIZER" == undefined ]]; then
+    # That's basicaly what --enable-sanitize-undefined does to turn off unaligned access
+    # elfutils heavily relies on on i386/x86_64 but without changing compiler flags along the way
+    sed -i 's/\(check_undefined_val\)=[0-9]/\1=1/' configure.ac
+fi
+
+autoreconf -i -f
+if ! ./configure --enable-maintainer-mode --disable-debuginfod --disable-libdebuginfod \
+	    CC="$CC" CFLAGS="-Wno-error $CFLAGS" CXX="$CXX" CXXFLAGS="-Wno-error $CXXFLAGS" LDFLAGS="$CFLAGS"; then
+    cat config.log
+    exit 1
+fi
+
+make -C config -j$(nproc) V=1
+make -C lib -j$(nproc) V=1
+make -C libelf -j$(nproc) V=1
+)
+
+make -C src BUILD_STATIC_ONLY=y V=1 clean
+make -C src -j$(nproc) CFLAGS="-I$(pwd)/elfutils/libelf $CFLAGS" BUILD_STATIC_ONLY=y V=1
+
+$CC $CFLAGS -Isrc -Iinclude -Iinclude/uapi -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -c fuzz/bpf-object-fuzzer.c -o bpf-object-fuzzer.o
+$CXX $CXXFLAGS $LIB_FUZZING_ENGINE bpf-object-fuzzer.o src/libbpf.a "$(pwd)/elfutils/libelf/libelf.a" -l:libz.a -o "$OUT/bpf-object-fuzzer"
+
+cp fuzz/bpf-object-fuzzer_seed_corpus.zip "$OUT"