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authorLibravatar Junio C Hamano <gitster@pobox.com>2018-10-26 14:22:13 +0900
committerLibravatar Junio C Hamano <gitster@pobox.com>2018-10-26 14:22:14 +0900
commit0c41b3b1a700f153e01d49913f0041378cc88cf7 (patch)
treeebac59b64116e0d653347ad4cce904ce163fec26
parentMerge branch 'rv/alias-help' (diff)
parentfuzz: add fuzz testing for packfile indices. (diff)
downloadtgif-0c41b3b1a700f153e01d49913f0041378cc88cf7.tar.xz
Merge branch 'js/fuzzer'
An experiment to fuzz test a few areas, hopefully we can gain more coverage to various areas. * js/fuzzer: fuzz: add fuzz testing for packfile indices. fuzz: add basic fuzz testing target.
-rw-r--r--.gitignore3
-rw-r--r--Makefile33
-rw-r--r--fuzz-pack-headers.c14
-rw-r--r--fuzz-pack-idx.c13
-rw-r--r--packfile.c44
-rw-r--r--packfile.h13
6 files changed, 101 insertions, 19 deletions
diff --git a/.gitignore b/.gitignore
index 9d1363a1eb..64b3377d40 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,6 @@
+/fuzz_corpora
+/fuzz-pack-headers
+/fuzz-pack-idx
/GIT-BUILD-OPTIONS
/GIT-CFLAGS
/GIT-LDFLAGS
diff --git a/Makefile b/Makefile
index d18ab0fe78..b08d5ea258 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 +684,14 @@ SCRIPTS = $(SCRIPT_SH_INS) \
ETAGS_TARGET = TAGS
+FUZZ_OBJS += fuzz-pack-headers.o
+FUZZ_OBJS += fuzz-pack-idx.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 =
@@ -2253,6 +2263,7 @@ 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
@@ -2951,6 +2962,7 @@ 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 $(ETAGS_TARGET) tags cscope*
@@ -3075,3 +3087,24 @@ cover_db: coverage-report
cover_db_html: cover_db
cover -report html -outputdir cover_db_html cover_db
+
+### Fuzz testing
+#
+# Building fuzz targets generally requires a special set of compiler flags that
+# are not necessarily appropriate for general builds, and that vary greatly
+# depending on the compiler version used.
+#
+# An example command to build against libFuzzer from LLVM 4.0.0:
+#
+# make CC=clang CXX=clang++ \
+# CFLAGS="-fsanitize-coverage=trace-pc-guard -fsanitize=address" \
+# LIB_FUZZING_ENGINE=/usr/lib/llvm-4.0/lib/libFuzzer.a \
+# fuzz-all
+#
+.PHONY: fuzz-all
+
+$(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;
+}
diff --git a/fuzz-pack-idx.c b/fuzz-pack-idx.c
new file mode 100644
index 0000000000..0c3d777aac
--- /dev/null
+++ b/fuzz-pack-idx.c
@@ -0,0 +1,13 @@
+#include "object-store.h"
+#include "packfile.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+ struct packed_git p;
+
+ load_idx("fuzz-input", GIT_SHA1_RAWSZ, (void *)data, size, &p);
+
+ return 0;
+}
diff --git a/packfile.c b/packfile.c
index 841b36182f..86074a76e9 100644
--- a/packfile.c
+++ b/packfile.c
@@ -80,10 +80,8 @@ void pack_report(void)
static int check_packed_git_idx(const char *path, struct packed_git *p)
{
void *idx_map;
- struct pack_idx_header *hdr;
size_t idx_size;
- uint32_t version, nr, i, *index;
- int fd = git_open(path);
+ int fd = git_open(path), ret;
struct stat st;
const unsigned int hashsz = the_hash_algo->rawsz;
@@ -101,16 +99,32 @@ static int check_packed_git_idx(const char *path, struct packed_git *p)
idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
- hdr = idx_map;
+ ret = load_idx(path, hashsz, idx_map, idx_size, p);
+
+ if (ret)
+ munmap(idx_map, idx_size);
+
+ return ret;
+}
+
+int load_idx(const char *path, const unsigned int hashsz, void *idx_map,
+ size_t idx_size, struct packed_git *p)
+{
+ struct pack_idx_header *hdr = idx_map;
+ uint32_t version, nr, i, *index;
+
+ if (idx_size < 4 * 256 + hashsz + hashsz)
+ return error("index file %s is too small", path);
+ if (idx_map == NULL)
+ return error("empty data");
+
if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
version = ntohl(hdr->idx_version);
- if (version < 2 || version > 2) {
- munmap(idx_map, idx_size);
+ if (version < 2 || version > 2)
return error("index file %s is version %"PRIu32
" and is not supported by this binary"
" (try upgrading GIT to a newer version)",
path, version);
- }
} else
version = 1;
@@ -120,10 +134,8 @@ static int check_packed_git_idx(const char *path, struct packed_git *p)
index += 2; /* skip index header */
for (i = 0; i < 256; i++) {
uint32_t n = ntohl(index[i]);
- if (n < nr) {
- munmap(idx_map, idx_size);
+ if (n < nr)
return error("non-monotonic index %s", path);
- }
nr = n;
}
@@ -135,10 +147,8 @@ static int check_packed_git_idx(const char *path, struct packed_git *p)
* - hash of the packfile
* - file checksum
*/
- if (idx_size != 4*256 + nr * (hashsz + 4) + hashsz + hashsz) {
- munmap(idx_map, idx_size);
+ if (idx_size != 4 * 256 + nr * (hashsz + 4) + hashsz + hashsz)
return error("wrong index v1 file size in %s", path);
- }
} else if (version == 2) {
/*
* Minimum size:
@@ -157,20 +167,16 @@ static int check_packed_git_idx(const char *path, struct packed_git *p)
unsigned long max_size = min_size;
if (nr)
max_size += (nr - 1)*8;
- if (idx_size < min_size || idx_size > max_size) {
- munmap(idx_map, idx_size);
+ if (idx_size < min_size || idx_size > max_size)
return error("wrong index v2 file size in %s", path);
- }
if (idx_size != min_size &&
/*
* make sure we can deal with large pack offsets.
* 31-bit signed offset won't be enough, neither
* 32-bit unsigned one will be.
*/
- (sizeof(off_t) <= 4)) {
- munmap(idx_map, idx_size);
+ (sizeof(off_t) <= 4))
return error("pack too large for current definition of off_t in %s", path);
- }
}
p->index_version = version;
diff --git a/packfile.h b/packfile.h
index 442625723d..6c4037605d 100644
--- a/packfile.h
+++ b/packfile.h
@@ -164,4 +164,17 @@ extern int has_pack_index(const unsigned char *sha1);
*/
extern int is_promisor_object(const struct object_id *oid);
+/*
+ * Expose a function for fuzz testing.
+ *
+ * load_idx() parses a block of memory as a packfile index and puts the results
+ * into a struct packed_git.
+ *
+ * This function should not be used directly. It is exposed here only so that we
+ * have a convenient entry-point for fuzz testing. For real uses, you should
+ * probably use open_pack_index() or parse_pack_index() instead.
+ */
+extern int load_idx(const char *path, const unsigned int hashsz, void *idx_map,
+ size_t idx_size, struct packed_git *p);
+
#endif