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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * FFmpeg is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with FFmpeg; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 #include "config.h"
20 #include "libavutil/imgutils.h"
21 #include "libavutil/opt.h"
22 
23 #include "libavcodec/avcodec.h"
24 #include "libavcodec/bsf.h"
25 #include "libavcodec/bsf_internal.h"
26 #include "libavcodec/bytestream.h"
27 #include "libavcodec/internal.h"
28 
29 int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
30 
error(const char * err)31 static void error(const char *err)
32 {
33     fprintf(stderr, "%s", err);
34     exit(1);
35 }
36 
37 static const AVBitStreamFilter *f = NULL;
38 
39 static const uint64_t FUZZ_TAG = 0x4741542D5A5A5546ULL;
40 
LLVMFuzzerTestOneInput(const uint8_t * data,size_t size)41 int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
42     const uint64_t fuzz_tag = FUZZ_TAG;
43     const uint8_t *last = data;
44     const uint8_t *end = data + size;
45     AVBSFContext *bsf = NULL;
46     AVPacket *pkt;
47     uint64_t keyframes = 0;
48     uint64_t flushpattern = -1;
49     int res;
50 
51     if (!f) {
52 #ifdef FFMPEG_BSF
53 #define BSF_SYMBOL0(BSF) ff_##BSF##_bsf
54 #define BSF_SYMBOL(BSF) BSF_SYMBOL0(BSF)
55         extern const AVBitStreamFilter BSF_SYMBOL(FFMPEG_BSF);
56         f = &BSF_SYMBOL(FFMPEG_BSF);
57 #endif
58         av_log_set_level(AV_LOG_PANIC);
59     }
60 
61     res = f ? av_bsf_alloc(f, &bsf) : av_bsf_get_null_filter(&bsf);
62     if (res < 0)
63         error("Failed memory allocation");
64     f = bsf->filter;
65 
66     if (size > 1024) {
67         GetByteContext gbc;
68         int extradata_size;
69         int flags;
70         size -= 1024;
71         bytestream2_init(&gbc, data + size, 1024);
72         bsf->par_in->width                      = bytestream2_get_le32(&gbc);
73         bsf->par_in->height                     = bytestream2_get_le32(&gbc);
74         bsf->par_in->bit_rate                   = bytestream2_get_le64(&gbc);
75         bsf->par_in->bits_per_coded_sample      = bytestream2_get_le32(&gbc);
76 
77         if (f->codec_ids) {
78             int i, id;
79             for (i = 0; f->codec_ids[i] != AV_CODEC_ID_NONE; i++);
80             id = f->codec_ids[bytestream2_get_byte(&gbc) % i];
81             bsf->par_in->codec_id = id;
82             bsf->par_in->codec_tag              = bytestream2_get_le32(&gbc);
83         }
84 
85         extradata_size = bytestream2_get_le32(&gbc);
86 
87         bsf->par_in->sample_rate                = bytestream2_get_le32(&gbc);
88         bsf->par_in->ch_layout.nb_channels      = (unsigned)bytestream2_get_le32(&gbc) % FF_SANE_NB_CHANNELS;
89         bsf->par_in->block_align                = bytestream2_get_le32(&gbc);
90         keyframes                               = bytestream2_get_le64(&gbc);
91         flushpattern                            = bytestream2_get_le64(&gbc);
92         flags                                   = bytestream2_get_byte(&gbc);
93 
94         if (flags & 0x20) {
95             if (!strcmp(f->name, "av1_metadata"))
96                 av_opt_set_int(bsf->priv_data, "td", bytestream2_get_byte(&gbc) % 3, 0);
97             else if (!strcmp(f->name, "h264_metadata") || !strcmp(f->name, "h265_metadata"))
98                 av_opt_set_int(bsf->priv_data, "aud", bytestream2_get_byte(&gbc) % 3, 0);
99             else if (!strcmp(f->name, "extract_extradata"))
100                 av_opt_set_int(bsf->priv_data, "remove", bytestream2_get_byte(&gbc) & 1, 0);
101         }
102 
103         if (extradata_size < size) {
104             bsf->par_in->extradata = av_mallocz(extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
105             if (bsf->par_in->extradata) {
106                 bsf->par_in->extradata_size = extradata_size;
107                 size -= bsf->par_in->extradata_size;
108                 memcpy(bsf->par_in->extradata, data + size, bsf->par_in->extradata_size);
109             }
110         }
111         if (av_image_check_size(bsf->par_in->width, bsf->par_in->height, 0, bsf))
112             bsf->par_in->width = bsf->par_in->height = 0;
113     }
114 
115     res = av_bsf_init(bsf);
116     if (res < 0) {
117         av_bsf_free(&bsf);
118         return 0; // Failure of av_bsf_init() does not imply that a issue was found
119     }
120 
121     pkt = av_packet_alloc();
122     if (!pkt)
123         error("Failed memory allocation");
124 
125     while (data < end) {
126         // Search for the TAG
127         while (data + sizeof(fuzz_tag) < end) {
128             if (data[0] == (fuzz_tag & 0xFF) && AV_RN64(data) == fuzz_tag)
129                 break;
130             data++;
131         }
132         if (data + sizeof(fuzz_tag) > end)
133             data = end;
134 
135         res = av_new_packet(pkt, data - last);
136         if (res < 0)
137             error("Failed memory allocation");
138         memcpy(pkt->data, last, data - last);
139         pkt->flags = (keyframes & 1) * AV_PKT_FLAG_DISCARD + (!!(keyframes & 2)) * AV_PKT_FLAG_KEY;
140         keyframes = (keyframes >> 2) + (keyframes<<62);
141         data += sizeof(fuzz_tag);
142         last = data;
143 
144         if (!(flushpattern & 7))
145             av_bsf_flush(bsf);
146         flushpattern = (flushpattern >> 3) + (flushpattern << 61);
147 
148         res = av_bsf_send_packet(bsf, pkt);
149         if (res < 0) {
150             av_packet_unref(pkt);
151             continue;
152         }
153         while (av_bsf_receive_packet(bsf, pkt) >= 0)
154             av_packet_unref(pkt);
155     }
156 
157     av_bsf_send_packet(bsf, NULL);
158     while (av_bsf_receive_packet(bsf, pkt) >= 0)
159         av_packet_unref(pkt);
160 
161     av_packet_free(&pkt);
162     av_bsf_free(&bsf);
163     return 0;
164 }
165