OSS-Fuzz: Add new fuzzer targets read processing

ossfuzz/Makefile.am

@@ -12,7 +12,8 @@ AM_CPPFLAGS = \
 	@LIBBFIO_CPPFLAGS@
 
 bin_PROGRAMS = \
-	handle_fuzzer
+	handle_fuzzer \
+	read_fuzzer
 
 handle_fuzzer_SOURCES = \
 	handle_fuzzer.cc \
@@ -31,6 +32,24 @@ handle_fuzzer_LDADD = \
 	@LIBCLOCALE_LIBADD@ \
 	@LIBCERROR_LIBADD@ \
 	@LIBINTL@
+
+read_fuzzer_SOURCES = \
+	read_fuzzer.cc \
+	ossfuzz_libbfio.h \
+	ossfuzz_libmodi.h
+
+read_fuzzer_LDADD = \
+	@LIB_FUZZING_ENGINE@ \
+	@LIBBFIO_LIBADD@ \
+	@LIBCPATH_LIBADD@ \
+	@LIBCFILE_LIBADD@ \
+	@LIBUNA_LIBADD@ \
+	@LIBCDATA_LIBADD@ \
+	../libmodi/libmodi.la \
+	@LIBCNOTIFY_LIBADD@ \
+	@LIBCLOCALE_LIBADD@ \
+	@LIBCERROR_LIBADD@ \
+	@LIBINTL@
 endif
 
 DISTCLEANFILES = \
@@ -40,4 +59,3 @@ DISTCLEANFILES = \
 splint-local:
 	@echo "Running splint on handle_fuzzer ..."
 	-splint -preproc -redef $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(handle_fuzzer_SOURCES)
-

ossfuzz/read_fuzzer.cc

@@ -0,0 +1,115 @@
+/*
+ * OSS-Fuzz target for the libmodi read-buffer (data) path
+ *
+ * The existing handle_fuzzer only opens and closes the image, so the band /
+ * sparse-image table parsing and the per-block decompression (zlib, bzip2,
+ * ADC, LZFSE/LZVN) used by the .dmg / UDIF read path are never reached. This
+ * target additionally reads the media so those parsers are exercised.
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+
+/* Note that some of the OSS-Fuzz engines use C++
+ */
+extern "C" {
+
+#include "ossfuzz_libbfio.h"
+#include "ossfuzz_libmodi.h"
+
+#if !defined( LIBMODI_HAVE_BFIO )
+
+LIBMODI_EXTERN \
+int libmodi_handle_open_file_io_handle(
+     libmodi_handle_t *handle,
+     libbfio_handle_t *file_io_handle,
+     int access_flags,
+     libmodi_error_t **error );
+
+#endif /* !defined( LIBMODI_HAVE_BFIO ) */
+
+int LLVMFuzzerTestOneInput(
+     const uint8_t *data,
+     size_t size )
+{
+	libbfio_handle_t *file_io_handle = NULL;
+	libmodi_handle_t *handle         = NULL;
+
+	if( libbfio_memory_range_initialize(
+	     &file_io_handle,
+	     NULL ) != 1 )
+	{
+		return( 0 );
+	}
+	if( libbfio_memory_range_set(
+	     file_io_handle,
+	     (uint8_t *) data,
+	     size,
+	     NULL ) != 1 )
+	{
+		goto on_error_libbfio;
+	}
+	if( libmodi_handle_initialize(
+	     &handle,
+	     NULL ) != 1 )
+	{
+		goto on_error_libbfio;
+	}
+	if( libmodi_handle_open_file_io_handle(
+	     handle,
+	     file_io_handle,
+	     LIBMODI_OPEN_READ,
+	     NULL ) != 1 )
+	{
+		goto on_error_libmodi;
+	}
+	/* Read the media to drive the band table / decompression parsing. */
+	{
+		size64_t media_size = 0;
+
+		if( libmodi_handle_get_media_size(
+		     handle,
+		     &media_size,
+		     NULL ) == 1 )
+		{
+			uint8_t buffer[ 4096 ];
+			off64_t offset = 0;
+			int iterations = 0;
+
+			while( ( offset < (off64_t) media_size )
+			    && ( iterations < 2048 ) )
+			{
+				ssize_t read_count = libmodi_handle_read_buffer_at_offset(
+				                      handle,
+				                      buffer,
+				                      sizeof( buffer ),
+				                      offset,
+				                      NULL );
+
+				if( read_count <= 0 )
+				{
+					break;
+				}
+				offset += read_count;
+				iterations++;
+			}
+		}
+	}
+	libmodi_handle_close(
+	 handle,
+	 NULL );
+
+on_error_libmodi:
+	libmodi_handle_free(
+	 &handle,
+	 NULL );
+
+on_error_libbfio:
+	libbfio_handle_free(
+	 &file_io_handle,
+	 NULL );
+
+	return( 0 );
+}
+
+} /* extern "C" */