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

["Arthur Chan via GitGitGadget" <gitgitgadget@xxxxxxxxx>]

From: Arthur Chan <arthur.chan@xxxxxxxxxxxxx>

Signed-off-by: Arthur Chan <arthur.chan@xxxxxxxxxxxxx>
---
    fuzz: add new oss-fuzz fuzzer for date.c / date.h
    
    This patch is aimed to add a new oss-fuzz fuzzer to the oss-fuzz
    directory for fuzzing date.c / date.h in the base directory.
    
    The .gitignore of the oss-fuzz directory and the Makefile have been
    modified to accommodate the new fuzzer fuzz-date.c.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1612%2Farthurscchan%2Fnew-fuzzer-date-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1612/arthurscchan/new-fuzzer-date-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1612

 Makefile             |  1 +
 oss-fuzz/.gitignore  |  1 +
 oss-fuzz/fuzz-date.c | 75 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+)
 create mode 100644 oss-fuzz/fuzz-date.c

diff --git a/Makefile b/Makefile
index 03adcb5a480..c9fe99a8c88 100644
--- a/Makefile
+++ b/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)
 
diff --git a/oss-fuzz/.gitignore b/oss-fuzz/.gitignore
index 9acb74412ef..2375e77b108 100644
--- a/oss-fuzz/.gitignore
+++ b/oss-fuzz/.gitignore
@@ -1,3 +1,4 @@
 fuzz-commit-graph
 fuzz-pack-headers
 fuzz-pack-idx
+fuzz-date
diff --git a/oss-fuzz/fuzz-date.c b/oss-fuzz/fuzz-date.c
new file mode 100644
index 00000000000..29bcaf595e4
--- /dev/null
+++ b/oss-fuzz/fuzz-date.c
@@ -0,0 +1,75 @@
+#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)
+{
+	int type;
+	int time;
+	int num;
+	char *str;
+	timestamp_t ts;
+	enum date_mode_type dmtype;
+	struct date_mode *dm;
+
+	if (size <= 8)
+	{
+		return 0;
+	}
+
+	type = (*((int *)data)) % 8;
+	data += 4;
+	size -= 4;
+
+	time = abs(*((int *)data));
+	data += 4;
+	size -= 4;
+
+	str = (char *)malloc(size+1);
+	if (!str)
+	{
+		return 0;
+	}
+	memcpy(str, data, size);
+	str[size] = '\0';
+
+	ts = approxidate_careful(str, &num);
+	free(str);
+
+	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;
+	}
+
+	dm = date_mode_from_type(dmtype);
+	dm->local = 1;
+	show_date(ts, time, dm);
+
+	date_mode_release(dm);
+
+	return 0;
+}

base-commit: dadef801b365989099a9929e995589e455c51fed
-- 
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