From: Josh Steadmon <steadmon@xxxxxxxxxx>
fuzz-pack-headers.c provides a fuzzing entry point compatible with
libFuzzer (and possibly other fuzzing engines).
Signed-off-by: Josh Steadmon <steadmon@xxxxxxxxxx>
---
.gitignore | 2 ++
Makefile | 32 ++++++++++++++++++++++++++++++++
fuzz-pack-headers.c | 14 ++++++++++++++
3 files changed, 48 insertions(+)
create mode 100644 fuzz-pack-headers.c
diff --git a/.gitignore b/.gitignore
index 9d1363a1eb..87a28b3115 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
+/fuzz_corpora
+/fuzz-pack-headers
/GIT-BUILD-OPTIONS
/GIT-CFLAGS
/GIT-LDFLAGS
diff --git a/Makefile b/Makefile
index 13e1c52478..7f5a19b8ab 100644
--- a/Makefile
+++ b/Makefile
@@ -590,6 +590,8 @@ XDIFF_OBJS =
VCSSVN_OBJS =
GENERATED_H =
EXTRA_CPPFLAGS =
+FUZZ_OBJS =
+FUZZ_PROGRAMS =
LIB_OBJS =
PROGRAM_OBJS =
PROGRAMS =
@@ -682,6 +684,13 @@ SCRIPTS = $(SCRIPT_SH_INS) \
ETAGS_TARGET = TAGS
+FUZZ_OBJS += fuzz-pack-headers.o
+
+# Always build fuzz objects even if not testing, to prevent bit-rot.
+all:: $(FUZZ_OBJS)
+
+FUZZ_PROGRAMS += $(patsubst %.o,%,$(FUZZ_OBJS))
+
# Empty...
EXTRA_PROGRAMS =
@@ -2250,6 +2259,7 @@ TEST_OBJS := $(patsubst %$X,%.o,$(TEST_PROGRAMS)) $(patsubst %,t/helper/%,$(TEST
OBJECTS := $(LIB_OBJS) $(BUILTIN_OBJS) $(PROGRAM_OBJS) $(TEST_OBJS) \
$(XDIFF_OBJS) \
$(VCSSVN_OBJS) \
+ $(FUZZ_OBJS) \
common-main.o \
git.o
ifndef NO_CURL
@@ -2937,6 +2947,7 @@ clean: profile-clean coverage-clean cocciclean
$(RM) $(LIB_FILE) $(XDIFF_LIB) $(VCSSVN_LIB)
$(RM) $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) git$X
$(RM) $(TEST_PROGRAMS) $(NO_INSTALL)
+ $(RM) $(FUZZ_PROGRAMS)
$(RM) -r bin-wrappers $(dep_dirs)
$(RM) -r po/build/
$(RM) *.pyc *.pyo */*.pyc */*.pyo command-list.h $(ETAGS_TARGET) tags cscope*
@@ -3061,3 +3072,24 @@ cover_db: coverage-report
cover_db_html: cover_db
cover -report html -outputdir cover_db_html cover_db
+
+### Fuzz testing
+#
+# Building fuzz targets generally requires a special set of compiler flags that
+# are not necessarily appropriate for general builds, and that vary greatly
+# depending on the compiler version used.
+#
+# An example command to build against libFuzzer from LLVM 4.0.0:
+#
+# make CC=clang CXX=clang++ \
+# CFLAGS="-fsanitize-coverage=trace-pc-guard -fsanitize=address" \
+# LIB_FUZZING_ENGINE=/usr/lib/llvm-4.0/lib/libFuzzer.a \
+# fuzz-all
+#
+.PHONY: fuzz-all
+
+$(FUZZ_PROGRAMS): all
+ $(QUIET_LINK)$(CXX) $(CFLAGS) $(LIB_OBJS) $(BUILTIN_OBJS) \
+ $(XDIFF_OBJS) $(EXTLIBS) git.o $@.o $(LIB_FUZZING_ENGINE) -o $@
+
+fuzz-all: $(FUZZ_PROGRAMS)
diff --git a/fuzz-pack-headers.c b/fuzz-pack-headers.c
new file mode 100644
index 0000000000..99da1d0fd3
--- /dev/null
+++ b/fuzz-pack-headers.c
@@ -0,0 +1,14 @@
+#include "packfile.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+ enum object_type type;
+ unsigned long len;
+
+ unpack_object_header_buffer((const unsigned char *)data,
+ (unsigned long)size, &type, &len);
+
+ return 0;
+}
--
2.19.0.605.g01d371f741-goog
