Try to replicate the ffmpeg fuzzer's behaviour with parsers and extradata

.gitignore

@@ -28,3 +28,4 @@ stamp-h1
 aac-enc
 compile
 fuzz-dec
+fuzz-dec-lavc

Makefile.am

@@ -47,6 +47,14 @@ aac_enc_SOURCES = aac-enc.c wavreader.c
 fuzz_dec_LDADD = libfdk-aac.la
 fuzz_dec_SOURCES = fuzz-dec.c
 
+if HAVE_LIBAVCODEC
+bin_PROGRAMS += fuzz-dec-lavc$(EXEEXT)
+
+fuzz_dec_lavc_LDADD = $(libavcodec_LIBS) $(libavutil_LIBS) libfdk-aac.la
+fuzz_dec_lavc_CFLAGS = $(libavcodec_CFLAGS) $(libavutil_CFLAGS) -DHAVE_LIBAVCODEC
+fuzz_dec_lavc_SOURCES = fuzz-dec.c
+endif
+
 noinst_HEADERS = wavreader.h
 endif
 

configure.ac

@@ -13,8 +13,14 @@ AC_ARG_ENABLE([example],
                 [enable example encoding program (default is no)])],
             [example=$enableval], [example=no])
 
+if test x$example = xyes; then
+	PKG_CHECK_MODULES([libavcodec], [libavcodec], [libavcodec=yes], [libavcodec=no])
+	PKG_CHECK_MODULES([libavutil], [libavutil], [libavutil=yes], [libavutil=no])
+fi
+
 dnl Automake conditionals to set
 AM_CONDITIONAL(EXAMPLE, test x$example = xyes)
+AM_CONDITIONAL(HAVE_LIBAVCODEC, test x$libavcodec = xyes)
 
 dnl Checks for programs.
 AC_PROG_CC
@@ -36,3 +42,6 @@ AC_SUBST(LIBS_PRIVATE)
 AC_CONFIG_FILES([Makefile
                  fdk-aac.pc])
 AC_OUTPUT
+if test x$example = xyes; then
+	AC_MSG_NOTICE([Found libavcodec: ${libavcodec}])
+fi

fuzz-dec.c

@@ -3,6 +3,10 @@
 #include <stdlib.h>
 #include <string.h>
 #include "aacdecoder_lib.h"
+#ifdef HAVE_LIBAVCODEC
+#include <libavcodec/avcodec.h>
+#include <libavutil/intreadwrite.h>
+#endif
 
 static const uint8_t tag[] = "FUZZ-TAG";
 
@@ -14,10 +18,38 @@ static void test(const uint8_t *ptr, int size) {
 	int decoder_buffer_size = 2048 * 2 * 8;
 	uint8_t *decoder_buffer = malloc(decoder_buffer_size);
 
-	HANDLE_AACDECODER decoder = aacDecoder_Open(TT_MP4_ADTS, 1);
+	int extradata_size = 0;
+	uint8_t *extradata = NULL;
+#ifdef HAVE_LIBAVCODEC
+	AVCodecParserContext *parser = NULL;
+	AVCodecContext *avctx = NULL;
+	if (size > 1024) {
+		const uint8_t* params = ptr + size - 1024;
+		size -= 1024;
+		params += 20; // width, height, bit_rate, bits_per_coded_sample
+		uint8_t flags = *params++;
+		if (flags & 1) {
+			parser = av_parser_init(AV_CODEC_ID_AAC);
+			avctx = avcodec_alloc_context3(NULL);
+		}
+		extradata_size = AV_RL32(params);
+		params += 4;
+		if (extradata_size < size) {
+			extradata = malloc(extradata_size);
+			size -= extradata_size;
+			memcpy(extradata, ptr + size, extradata_size);
+		}
+	}
+#endif
+
+	HANDLE_AACDECODER decoder = aacDecoder_Open(extradata_size ? TT_MP4_RAW : TT_MP4_ADTS, 1);
 	aacDecoder_SetParam(decoder, AAC_CONCEAL_METHOD, 1);
 	aacDecoder_SetParam(decoder, AAC_PCM_LIMITER_ENABLE, 0);
 
+	if (extradata_size) {
+		aacDecoder_ConfigRaw(decoder, &extradata, &extradata_size);
+	}
+
 	while (1) {
 		const uint8_t* start = ptr;
 		UINT valid, buffer_size;
@@ -31,19 +63,34 @@ static void test(const uint8_t *ptr, int size) {
 		if (ptr + tagsize > end)
 			ptr = end;
 
-		do {
-			valid = buffer_size = ptr - start;
-			err = aacDecoder_Fill(decoder, (UCHAR**) &start, &buffer_size, &valid);
-			start += buffer_size - valid;
+
+		while (start < ptr) {
+			const uint8_t *input = start;
+			const uint8_t *inputend = ptr;
+#ifdef HAVE_LIBAVCODEC
+			if (parser) {
+				int parse_size;
+				int ret = av_parser_parse2(parser, avctx, (uint8_t**) &input, &parse_size, start, ptr - start, 0, 0, 0);
+				start += ret;
+				inputend = input + parse_size;
+			} else
+#endif
+				start = ptr;
+
+			while (input && input < inputend) {
+				valid = buffer_size = inputend - input;
+				err = aacDecoder_Fill(decoder, (UCHAR**) &input, &buffer_size, &valid);
+				input += buffer_size - valid;
 				if (err == AAC_DEC_NOT_ENOUGH_BITS)
 					continue;
 				if (err == AAC_DEC_OK)
 					err = aacDecoder_DecodeFrame(decoder, (INT_PCM *) decoder_buffer, decoder_buffer_size / sizeof(INT_PCM), 0);
 				if (err != AAC_DEC_NOT_ENOUGH_BITS && err != AAC_DEC_OK)
 					break;
-		} while (start < ptr);
+			}
 
 			aacDecoder_GetStreamInfo(decoder);
+		}
 
 		if (ptr + tagsize <= end) {
 			ptr += tagsize;
@@ -63,6 +110,13 @@ static void test(const uint8_t *ptr, int size) {
 	}
 	free(decoder_buffer);
 	aacDecoder_Close(decoder);
+	free(extradata);
+#ifdef HAVE_LIBAVCODEC
+	if (parser) {
+		av_parser_close(parser);
+		avcodec_free_context(&avctx);
+	}
+#endif
 }
 
 int main(int argc, char *argv[]) {
@@ -70,6 +124,10 @@ int main(int argc, char *argv[]) {
 	int size;
 	uint8_t *buf;
 
+#ifdef HAVE_LIBAVCODEC
+	avcodec_register_all();
+#endif
+
 	if (argc < 2) {
 		printf("%s file\n", argv[0]);
 		return 0;