Add minimal test program for fuzzing the tar parser

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

3 files changed, 57 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index d03be1e..3f0a58e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -23,6 +23,7 @@ rdsquashfs
 sqfs2tar
 tar2sqfs
 sqfsdiff
+tar_fuzz
 test_*
 test-*
 fscompare
diff --git a/tar/Makemodule.am b/tar/Makemodule.am
index b8674c2..551f4cd 100644
--- a/tar/Makemodule.am
+++ b/tar/Makemodule.am
@@ -8,4 +8,8 @@ tar2sqfs_CFLAGS = $(AM_CFLAGS) $(PTHREAD_CFLAGS)
 tar2sqfs_LDADD += $(XZ_LIBS) $(ZLIB_LIBS) $(LZO_LIBS) $(LZ4_LIBS) $(ZSTD_LIBS)
 tar2sqfs_LDADD += $(PTHREAD_LIBS)
 
+tar_fuzz_SOURCES = tar/tar_fuzz.c
+tar_fuzz_LDADD = libtar.a libutil.a
+
 bin_PROGRAMS += sqfs2tar tar2sqfs
+noinst_PROGRAMS += tar_fuzz
diff --git a/tar/tar_fuzz.c b/tar/tar_fuzz.c
new file mode 100644
index 0000000..4dc20f5
--- /dev/null
+++ b/tar/tar_fuzz.c
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * tar_fuzz.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "util.h"
+#include "tar.h"
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <fcntl.h>
+
+int main(int argc, char **argv)
+{
+	tar_header_decoded_t hdr;
+	int fd, ret;
+
+	if (argc != 2) {
+		fputs("usage: tar_fuzz <tarball>\n", stderr);
+		return EXIT_FAILURE;
+	}
+
+	fd = open(argv[1], O_RDONLY);
+	if (fd < 0) {
+		perror(argv[1]);
+		return EXIT_FAILURE;
+	}
+
+	for (;;) {
+		ret = read_header(fd, &hdr);
+		if (ret > 0)
+			break;
+		if (ret < 0)
+			goto fail;
+
+		ret = lseek(fd, hdr.sb.st_size, SEEK_CUR);
+
+		clear_header(&hdr);
+		if (ret)
+			goto fail;
+	}
+
+	close(fd);
+	return EXIT_SUCCESS;
+fail:
+	close(fd);
+	return EXIT_FAILURE;
+}