It should make it easier to reproduce bugs found by OSS-Fuzz locally without docker. The fuzz target can be built and run with the corpus OSS-Fuzz has accumulated so far by running the following commands: ``` ./scripts/oss-fuzz.sh wget https://storage.googleapis.com/selinux-backup.clusterfuzz-external.appspot.com/corpus/libFuzzer/selinux_secilc-fuzzer/public.zip unzip -d CORPUS public.zip ./out/secilc-fuzzer CORPUS/ ``` It was tested in https://github.com/google/oss-fuzz/pull/6026 by pointing OSS-Fuzz to the branch containing the patch and running all the tests with all the sanitizers and fuzzing engines there: https://github.com/google/oss-fuzz/actions/runs/1024673143 Signed-off-by: Evgeny Vereshchagin <evvers@xxxxx> --- libsepol/fuzz/secilc-fuzzer.c | 69 +++++++++++++++++++++++++++++++++++ scripts/oss-fuzz.sh | 28 ++++++++++++++ 2 files changed, 97 insertions(+) create mode 100644 libsepol/fuzz/secilc-fuzzer.c create mode 100755 scripts/oss-fuzz.sh diff --git a/libsepol/fuzz/secilc-fuzzer.c b/libsepol/fuzz/secilc-fuzzer.c new file mode 100644 index 00000000..255b3241 --- /dev/null +++ b/libsepol/fuzz/secilc-fuzzer.c @@ -0,0 +1,69 @@ +#include <stdlib.h> +#include <stdio.h> +#include <stdint.h> +#include <string.h> +#include <getopt.h> +#include <sys/stat.h> + +#include <sepol/cil/cil.h> +#include <sepol/policydb.h> + +int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { + enum cil_log_level log_level = CIL_ERR; + struct sepol_policy_file *pf = NULL; + FILE *dev_null = NULL; + int target = SEPOL_TARGET_SELINUX; + int disable_dontaudit = 0; + int multiple_decls = 0; + int disable_neverallow = 0; + int preserve_tunables = 0; + int policyvers = POLICYDB_VERSION_MAX; + int mls = -1; + int attrs_expand_generated = 0; + struct cil_db *db = NULL; + sepol_policydb_t *pdb = NULL; + + cil_set_log_level(log_level); + + cil_db_init(&db); + cil_set_disable_dontaudit(db, disable_dontaudit); + cil_set_multiple_decls(db, multiple_decls); + cil_set_disable_neverallow(db, disable_neverallow); + cil_set_preserve_tunables(db, preserve_tunables); + cil_set_mls(db, mls); + cil_set_target_platform(db, target); + cil_set_policy_version(db, policyvers); + cil_set_attrs_expand_generated(db, attrs_expand_generated); + + if (cil_add_file(db, "fuzz", (const char *)data, size) != SEPOL_OK) + goto exit; + + if (cil_compile(db) != SEPOL_OK) + goto exit; + + if (cil_build_policydb(db, &pdb) != SEPOL_OK) + goto exit; + + if (sepol_policydb_optimize(pdb) != SEPOL_OK) + goto exit; + + dev_null = fopen("/dev/null", "w"); + if (dev_null == NULL) + goto exit; + + if (sepol_policy_file_create(&pf) != 0) + goto exit; + + sepol_policy_file_set_fp(pf, dev_null); + + if (sepol_policydb_write(pdb, pf) != 0) + goto exit; +exit: + if (dev_null != NULL) + fclose(dev_null); + + cil_db_destroy(&db); + sepol_policydb_free(pdb); + sepol_policy_file_free(pf); + return 0; +} diff --git a/scripts/oss-fuzz.sh b/scripts/oss-fuzz.sh new file mode 100755 index 00000000..9e720a5c --- /dev/null +++ b/scripts/oss-fuzz.sh @@ -0,0 +1,28 @@ +#!/bin/bash + +set -eux + +export DESTDIR=$(pwd)/DESTDIR + +SANITIZER=${SANITIZER:-address} +flags="-O1 -fno-omit-frame-pointer -gline-tables-only -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:-$flags} + +export LDFLAGS="${LDFLAGS:-} $CFLAGS" + +export OUT=${OUT:-$(pwd)/out} +mkdir -p $OUT + +export LIB_FUZZING_ENGINE=${LIB_FUZZING_ENGINE:--fsanitize=fuzzer} + +find -name Makefile | xargs sed -i 's/,-z,defs//' +make V=1 -j$(nproc) install + +$CC $CFLAGS -I$DESTDIR/usr/include -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -c -o secilc-fuzzer.o libsepol/fuzz/secilc-fuzzer.c +$CXX $CXXFLAGS $LIB_FUZZING_ENGINE secilc-fuzzer.o $DESTDIR/usr/lib/libsepol.a -o $OUT/secilc-fuzzer +zip -r $OUT/secilc-fuzzer_seed_corpus.zip secilc/test -- 2.31.1
