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

1 files changed, 56 insertions, 0 deletions

diff --git a/tests/ossfuzz/fuzz_common.h b/tests/ossfuzz/fuzz_common.h
new file mode 100644
index 00000000..ce3f9345
--- /dev/null
+++ b/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();
+	}
+}