Tests: Move common OSS-Fuzz target code to .h file.

tests/ossfuzz/fuzz_common.h

@@ -0,0 +1,56 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       fuzz_decode_auto.c
+/// \brief      Fuzz test program for liblzma lzma_auto_decoder()
+//
+//  Author:     Maksym Vatsyk
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include <inttypes.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "lzma.h"
+
+// Some header values can make liblzma allocate a lot of RAM
+// (up to about 4 GiB with liblzma 5.2.x). We set a limit here to
+// prevent extreme allocations when fuzzing.
+#define MEM_LIMIT (300 << 20) // 300 MiB
+
+
+// Output buffer for decompressed data. This is write only; nothing cares
+// about the actual data written here.
+static uint8_t outbuf[4096];
+
+
+static void
+fuzz_code(lzma_stream *stream, const uint8_t *inbuf, size_t inbuf_size) {
+	// Give the whole input buffer at once to liblzma.
+	// Output buffer isn't initialized as liblzma only writes to it.
+	stream->next_in = inbuf;
+	stream->avail_in = inbuf_size;
+	stream->next_out = outbuf;
+	stream->avail_out = sizeof(outbuf);
+
+	lzma_ret ret;
+	while ((ret = lzma_code(stream, LZMA_FINISH)) == LZMA_OK) {
+		if (stream->avail_out == 0) {
+			// outbuf became full. We don't care about the
+			// uncompressed data there, so we simply reuse
+			// the outbuf and overwrite the old data.
+			stream->next_out = outbuf;
+			stream->avail_out = sizeof(outbuf);
+		}
+	}
+
+	// LZMA_PROG_ERROR should never happen as long as the code calling
+	// the liblzma functions is correct. Thus LZMA_PROG_ERROR is a sign
+	// of a bug in either this function or in liblzma.
+	if (ret == LZMA_PROG_ERROR) {
+		fprintf(stderr, "lzma_code() returned LZMA_PROG_ERROR\n");
+		abort();
+	}
+}

tests/ossfuzz/fuzz_decode_stream.c

@@ -1,10 +1,11 @@
 ///////////////////////////////////////////////////////////////////////////////
 //
-/// \file       fuzz.c
+/// \file       fuzz_decode_stream.c
 /// \brief      Fuzz test program for liblzma
 //
 //  Author:     Lasse Collin
 //
+//
 //  This file has been put into the public domain.
 //  You can do whatever you want with this file.
 //
@@ -14,66 +15,36 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include "lzma.h"
-
+#include "fuzz_common.h"
-
-// Output buffer for decompressed data. This is write only; nothing cares
-// about the actual data written here.
-static uint8_t outbuf[4096];
 
 
 extern int
 LLVMFuzzerTestOneInput(const uint8_t *inbuf, size_t inbuf_size)
 {
-	// Some header values can make liblzma allocate a lot of RAM
+	lzma_stream strm = LZMA_STREAM_INIT;
-	// (up to about 4 GiB with liblzma 5.2.x). We set a limit here to
+	// Initialize a LZMA alone decoder using the memory usage limit
-	// prevent extreme allocations when fuzzing.
+	// defined in fuzz_common.h
-	const uint64_t memlimit = 300 << 20; // 300 MiB
+	//
-
-	// Initialize a .xz decoder using the above memory usage limit.
 	// Enable support for concatenated .xz files which is used when
 	// decompressing regular .xz files (instead of data embedded inside
 	// some other file format). Integrity checks on the uncompressed
 	// data are ignored to make fuzzing more effective (incorrect check
 	// values won't prevent the decoder from processing more input).
 	//
-	// The flag LZMA_IGNORE_CHECK doesn't disable verification of header
+	// The flag LZMA_IGNORE_CHECK doesn't disable verification of
-	// CRC32 values. Those checks are disabled when liblzma is built
+	// header CRC32 values. Those checks are disabled when liblzma is
-	// with the #define FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION.
+	// built with the #define FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION.
-	lzma_stream strm = LZMA_STREAM_INIT;
+
-	lzma_ret ret = lzma_stream_decoder(&strm, memlimit,
+	if (lzma_stream_decoder(&strm, MEM_LIMIT,
-			LZMA_CONCATENATED | LZMA_IGNORE_CHECK);
+			LZMA_CONCATENATED | LZMA_IGNORE_CHECK) != LZMA_OK) {
-	if (ret != LZMA_OK) {
 		// This should never happen unless the system has
 		// no free memory or address space to allow the small
 		// allocations that the initialization requires.
-		fprintf(stderr, "lzma_stream_decoder() failed (%d)\n", ret);
+		fprintf(stderr, "lzma_stream_decoder() failed\n");
 		abort();
 	}
 
-	// Give the whole input buffer at once to liblzma.
+	fuzz_code(&strm, inbuf, inbuf_size);
-	// Output buffer isn't initialized as liblzma only writes to it.
-	strm.next_in = inbuf;
-	strm.avail_in = inbuf_size;
-	strm.next_out = outbuf;
-	strm.avail_out = sizeof(outbuf);
-
-	while ((ret = lzma_code(&strm, LZMA_FINISH)) == LZMA_OK) {
-		if (strm.avail_out == 0) {
-			// outbuf became full. We don't care about the
-			// uncompressed data there, so we simply reuse
-			// the outbuf and overwrite the old data.
-			strm.next_out = outbuf;
-			strm.avail_out = sizeof(outbuf);
-		}
-	}
-
-	// LZMA_PROG_ERROR should never happen as long as the code calling
-	// the liblzma functions is correct. Thus LZMA_PROG_ERROR is a sign
-	// of a bug in either this function or in liblzma.
-	if (ret == LZMA_PROG_ERROR) {
-		fprintf(stderr, "lzma_code() returned LZMA_PROG_ERROR\n");
-		abort();
-	}
 
 	// Free the allocated memory.
 	lzma_end(&strm);