fuzz: add new oss-fuzz fuzzer for date.c / date.h

Signed-off-by: Arthur Chan <arthur.chan@adalogics.com>

Makefile

@@ -752,6 +752,7 @@ ETAGS_TARGET = TAGS
 FUZZ_OBJS += oss-fuzz/fuzz-commit-graph.o
 FUZZ_OBJS += oss-fuzz/fuzz-pack-headers.o
 FUZZ_OBJS += oss-fuzz/fuzz-pack-idx.o
+FUZZ_OBJS += oss-fuzz/fuzz-date.o
 .PHONY: fuzz-objs
 fuzz-objs: $(FUZZ_OBJS)
 

oss-fuzz/.gitignore

@@ -1,3 +1,4 @@
 fuzz-commit-graph
 fuzz-pack-headers
 fuzz-pack-idx
+fuzz-date

oss-fuzz/fuzz-date.c

@@ -0,0 +1,69 @@
+#include "git-compat-util.h"
+#include "date.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+	if (size <= 8)
+	{
+		return 0;
+	}
+
+	int type = (*((int *)data)) % 8;
+	data += 4;
+	size -= 4;
+
+	int time = abs(*((int *)data));
+	data += 4;
+	size -= 4;
+
+	char *str = (char *)malloc(size+1);
+	if (str == NULL)
+	{
+		return 0;
+	}
+	memcpy(str, data, size);
+	str[size] = '\0';
+
+	int errno;
+	timestamp_t ts = approxidate_careful(str, &errno);
+	free(str);
+
+	enum date_mode_type dmtype;
+	switch(type)
+	{
+		case 0: default:
+			dmtype = DATE_NORMAL;
+			break;
+		case 1:
+			dmtype = DATE_HUMAN;
+			break;
+		case 2:
+			dmtype = DATE_SHORT;
+			break;
+		case 3:
+			dmtype = DATE_ISO8601;
+			break;
+		case 4:
+			dmtype = DATE_ISO8601_STRICT;
+			break;
+		case 5:
+			dmtype = DATE_RFC2822;
+			break;
+		case 6:
+			dmtype = DATE_RAW;
+			break;
+		case 7:
+			dmtype = DATE_UNIX;
+			break;
+	}
+
+	struct date_mode *dm = date_mode_from_type(dmtype);
+	dm->local = 1;
+	show_date(ts, time, dm);
+
+	date_mode_release(dm);
+
+	return 0;
+}