Commit message: avcodec/pngdec: Fix off by 1 size in decode_zbuf()

Fixes out of array access
Fixes: 444/fuzz-2-ffmpeg_VIDEO_AV_CODEC_ID_PNG_fuzzer

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
CVE: CVE-2017-7866
CWE: CWE-787
Vulnerability description: FFmpeg before 2017-01-23 has an out-of-bounds write caused by a stack-based buffer overflow related to the decode_zbuf function in libavcodec/pngdec.c.

Project: FFmpeg

static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s,
                             uint32_t length)
{
    uint32_t sequence_number;
    int cur_w, cur_h, x_offset, y_offset, dispose_op, blend_op;

    if (length != 26)
        return AVERROR_INVALIDDATA;

    if (!(s->state & PNG_IHDR)) {
        av_log(avctx, AV_LOG_ERROR, "fctl before IHDR\n");
        return AVERROR_INVALIDDATA;
    }

    s->last_w = s->cur_w;
    s->last_h = s->cur_h;
    s->last_x_offset = s->x_offset;
    s->last_y_offset = s->y_offset;
    s->last_dispose_op = s->dispose_op;

    sequence_number = bytestream2_get_be32(&s->gb);
    cur_w           = bytestream2_get_be32(&s->gb);
    cur_h           = bytestream2_get_be32(&s->gb);
    x_offset        = bytestream2_get_be32(&s->gb);
    y_offset        = bytestream2_get_be32(&s->gb);
    bytestream2_skip(&s->gb, 4); /* delay_num (2), delay_den (2) */
    dispose_op      = bytestream2_get_byte(&s->gb);
    blend_op        = bytestream2_get_byte(&s->gb);
    bytestream2_skip(&s->gb, 4); /* crc */

    if (sequence_number == 0 &&
        (cur_w != s->width ||
         cur_h != s->height ||
         x_offset != 0 ||
         y_offset != 0) ||
        cur_w <= 0 || cur_h <= 0 ||
        x_offset < 0 || y_offset < 0 ||
        cur_w > s->width - x_offset|| cur_h > s->height - y_offset)
            return AVERROR_INVALIDDATA;

    if (blend_op != APNG_BLEND_OP_OVER && blend_op != APNG_BLEND_OP_SOURCE) {
        av_log(avctx, AV_LOG_ERROR, "Invalid blend_op %d\n", blend_op);
        return AVERROR_INVALIDDATA;
    }

    if ((sequence_number == 0 || !s->previous_picture.f->data[0]) &&
        dispose_op == APNG_DISPOSE_OP_PREVIOUS) {
        dispose_op = APNG_DISPOSE_OP_BACKGROUND;
    }

    if (blend_op == APNG_BLEND_OP_OVER && !s->has_trns && (
            avctx->pix_fmt == AV_PIX_FMT_RGB24 ||
            avctx->pix_fmt == AV_PIX_FMT_RGB48BE ||
            avctx->pix_fmt == AV_PIX_FMT_PAL8 ||
            avctx->pix_fmt == AV_PIX_FMT_GRAY8 ||
            avctx->pix_fmt == AV_PIX_FMT_GRAY16BE ||
            avctx->pix_fmt == AV_PIX_FMT_MONOBLACK
        )) {
        blend_op = APNG_BLEND_OP_SOURCE;
    }

    s->cur_w      = cur_w;
    s->cur_h      = cur_h;
    s->x_offset   = x_offset;
    s->y_offset   = y_offset;
    s->dispose_op = dispose_op;
    s->blend_op   = blend_op;

    return 0;
}

Project: FFmpeg
File: pngdec.c

static int decode_frame_apng(AVCodecContext *avctx,
                        void *data, int *got_frame,
                        AVPacket *avpkt)
{
    PNGDecContext *const s = avctx->priv_data;
    int ret;
    AVFrame *p;

    ff_thread_release_buffer(avctx, &s->last_picture);
    FFSWAP(ThreadFrame, s->picture, s->last_picture);
    p = s->picture.f;

    if (!(s->state & PNG_IHDR)) {
        if (!avctx->extradata_size)
            return AVERROR_INVALIDDATA;

        /* only init fields, there is no zlib use in extradata */
        s->zstream.zalloc = ff_png_zalloc;
        s->zstream.zfree  = ff_png_zfree;

        bytestream2_init(&s->gb, avctx->extradata, avctx->extradata_size);
        if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
            goto end;
    }

    /* reset state for a new frame */
    if ((ret = inflateInit(&s->zstream)) != Z_OK) {
        av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
        ret = AVERROR_EXTERNAL;
        goto end;
    }
    s->y = 0;
    s->state &= ~(PNG_IDAT | PNG_ALLIMAGE);
    bytestream2_init(&s->gb, avpkt->data, avpkt->size);
    if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
        goto end;

    if (!(s->state & PNG_ALLIMAGE))
        av_log(avctx, AV_LOG_WARNING, "Frame did not contain a complete image\n");
    if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
        ret = AVERROR_INVALIDDATA;
        goto end;
    }
    if ((ret = av_frame_ref(data, s->picture.f)) < 0)
        goto end;

    *got_frame = 1;
    ret = bytestream2_tell(&s->gb);

end:
    inflateEnd(&s->zstream);
    return ret;
}

Project: FFmpeg
File: pngdec.c

static int decode_frame_png(AVCodecContext *avctx,
                        void *data, int *got_frame,
                        AVPacket *avpkt)
{
    PNGDecContext *const s = avctx->priv_data;
    const uint8_t *buf     = avpkt->data;
    int buf_size           = avpkt->size;
    AVFrame *p;
    int64_t sig;
    int ret;

    ff_thread_release_buffer(avctx, &s->last_picture);
    FFSWAP(ThreadFrame, s->picture, s->last_picture);
    p = s->picture.f;

    bytestream2_init(&s->gb, buf, buf_size);

    /* check signature */
    sig = bytestream2_get_be64(&s->gb);
    if (sig != PNGSIG &&
        sig != MNGSIG) {
        av_log(avctx, AV_LOG_ERROR, "Invalid PNG signature 0x%08"PRIX64".\n", sig);
        return AVERROR_INVALIDDATA;
    }

    s->y = s->state = s->has_trns = 0;

    /* init the zlib */
    s->zstream.zalloc = ff_png_zalloc;
    s->zstream.zfree  = ff_png_zfree;
    s->zstream.opaque = NULL;
    ret = inflateInit(&s->zstream);
    if (ret != Z_OK) {
        av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
        return AVERROR_EXTERNAL;
    }

    if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
        goto the_end;

    if (avctx->skip_frame == AVDISCARD_ALL) {
        *got_frame = 0;
        ret = bytestream2_tell(&s->gb);
        goto the_end;
    }

    if ((ret = av_frame_ref(data, s->picture.f)) < 0)
        return ret;

    *got_frame = 1;

    ret = bytestream2_tell(&s->gb);
the_end:
    inflateEnd(&s->zstream);
    s->crow_buf = NULL;
    return ret;
}

Project: FFmpeg
File: pngdec.c

static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s,
                             uint32_t length, AVFrame *p)
{
    int ret;
    size_t byte_depth = s->bit_depth > 8 ? 2 : 1;

    if (!(s->state & PNG_IHDR)) {
        av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
        return AVERROR_INVALIDDATA;
    }
    if (!(s->state & PNG_IDAT)) {
        /* init image info */
        avctx->width  = s->width;
        avctx->height = s->height;

        s->channels       = ff_png_get_nb_channels(s->color_type);
        s->bits_per_pixel = s->bit_depth * s->channels;
        s->bpp            = (s->bits_per_pixel + 7) >> 3;
        s->row_size       = (s->cur_w * s->bits_per_pixel + 7) >> 3;

        if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
                s->color_type == PNG_COLOR_TYPE_RGB) {
            avctx->pix_fmt = AV_PIX_FMT_RGB24;
        } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
                s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
            avctx->pix_fmt = AV_PIX_FMT_RGBA;
        } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
                s->color_type == PNG_COLOR_TYPE_GRAY) {
            avctx->pix_fmt = AV_PIX_FMT_GRAY8;
        } else if (s->bit_depth == 16 &&
                s->color_type == PNG_COLOR_TYPE_GRAY) {
            avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
        } else if (s->bit_depth == 16 &&
                s->color_type == PNG_COLOR_TYPE_RGB) {
            avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
        } else if (s->bit_depth == 16 &&
                s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
            avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
        } else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
                s->color_type == PNG_COLOR_TYPE_PALETTE) {
            avctx->pix_fmt = AV_PIX_FMT_PAL8;
        } else if (s->bit_depth == 1 && s->bits_per_pixel == 1 && avctx->codec_id != AV_CODEC_ID_APNG) {
            avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
        } else if (s->bit_depth == 8 &&
                s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
            avctx->pix_fmt = AV_PIX_FMT_YA8;
        } else if (s->bit_depth == 16 &&
                s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
            avctx->pix_fmt = AV_PIX_FMT_YA16BE;
        } else {
            av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
                    "and color type %d\n",
                    s->bit_depth, s->color_type);
            return AVERROR_INVALIDDATA;
        }

        if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE) {
            switch (avctx->pix_fmt) {
            case AV_PIX_FMT_RGB24:
                avctx->pix_fmt = AV_PIX_FMT_RGBA;
                break;

            case AV_PIX_FMT_RGB48BE:
                avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
                break;

            case AV_PIX_FMT_GRAY8:
                avctx->pix_fmt = AV_PIX_FMT_YA8;
                break;

            case AV_PIX_FMT_GRAY16BE:
                avctx->pix_fmt = AV_PIX_FMT_YA16BE;
                break;

            default:
                avpriv_request_sample(avctx, "bit depth %d "
                        "and color type %d with TRNS",
                        s->bit_depth, s->color_type);
                return AVERROR_INVALIDDATA;
            }

            s->bpp += byte_depth;
        }

        if ((ret = ff_thread_get_buffer(avctx, &s->picture, AV_GET_BUFFER_FLAG_REF)) < 0)
            return ret;
        if (avctx->codec_id == AV_CODEC_ID_APNG && s->last_dispose_op != APNG_DISPOSE_OP_PREVIOUS) {
            ff_thread_release_buffer(avctx, &s->previous_picture);
            if ((ret = ff_thread_get_buffer(avctx, &s->previous_picture, AV_GET_BUFFER_FLAG_REF)) < 0)
                return ret;
        }
        ff_thread_finish_setup(avctx);

        p->pict_type        = AV_PICTURE_TYPE_I;
        p->key_frame        = 1;
        p->interlaced_frame = !!s->interlace_type;

        /* compute the compressed row size */
        if (!s->interlace_type) {
            s->crow_size = s->row_size + 1;
        } else {
            s->pass          = 0;
            s->pass_row_size = ff_png_pass_row_size(s->pass,
                    s->bits_per_pixel,
                    s->cur_w);
            s->crow_size = s->pass_row_size + 1;
        }
        ff_dlog(avctx, "row_size=%d crow_size =%d\n",
                s->row_size, s->crow_size);
        s->image_buf      = p->data[0];
        s->image_linesize = p->linesize[0];
        /* copy the palette if needed */
        if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
            memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
        /* empty row is used if differencing to the first row */
        av_fast_padded_mallocz(&s->last_row, &s->last_row_size, s->row_size);
        if (!s->last_row)
            return AVERROR_INVALIDDATA;
        if (s->interlace_type ||
                s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
            av_fast_padded_malloc(&s->tmp_row, &s->tmp_row_size, s->row_size);
            if (!s->tmp_row)
                return AVERROR_INVALIDDATA;
        }
        /* compressed row */
        av_fast_padded_malloc(&s->buffer, &s->buffer_size, s->row_size + 16);
        if (!s->buffer)
            return AVERROR(ENOMEM);

        /* we want crow_buf+1 to be 16-byte aligned */
        s->crow_buf          = s->buffer + 15;
        s->zstream.avail_out = s->crow_size;
        s->zstream.next_out  = s->crow_buf;
    }

    s->state |= PNG_IDAT;

    /* set image to non-transparent bpp while decompressing */
    if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE)
        s->bpp -= byte_depth;

    ret = png_decode_idat(s, length);

    if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE)
        s->bpp += byte_depth;

    if (ret < 0)
        return ret;

    bytestream2_skip(&s->gb, 4); /* crc */

    return 0;
}

Project: FFmpeg
File: pngdec.c

static int decode_ihdr_chunk(AVCodecContext *avctx, PNGDecContext *s,
                             uint32_t length)
{
    if (length != 13)
        return AVERROR_INVALIDDATA;

    if (s->state & PNG_IDAT) {
        av_log(avctx, AV_LOG_ERROR, "IHDR after IDAT\n");
        return AVERROR_INVALIDDATA;
    }

    if (s->state & PNG_IHDR) {
        av_log(avctx, AV_LOG_ERROR, "Multiple IHDR\n");
        return AVERROR_INVALIDDATA;
    }

    s->width  = s->cur_w = bytestream2_get_be32(&s->gb);
    s->height = s->cur_h = bytestream2_get_be32(&s->gb);
    if (av_image_check_size(s->width, s->height, 0, avctx)) {
        s->cur_w = s->cur_h = s->width = s->height = 0;
        av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
        return AVERROR_INVALIDDATA;
    }
    s->bit_depth        = bytestream2_get_byte(&s->gb);
    s->color_type       = bytestream2_get_byte(&s->gb);
    s->compression_type = bytestream2_get_byte(&s->gb);
    s->filter_type      = bytestream2_get_byte(&s->gb);
    s->interlace_type   = bytestream2_get_byte(&s->gb);
    bytestream2_skip(&s->gb, 4); /* crc */
    s->state |= PNG_IHDR;
    if (avctx->debug & FF_DEBUG_PICT_INFO)
        av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d "
                "compression_type=%d filter_type=%d interlace_type=%d\n",
                s->width, s->height, s->bit_depth, s->color_type,
                s->compression_type, s->filter_type, s->interlace_type);

    return 0;
}

Project: FFmpeg
File: pngdec.c

static int decode_phys_chunk(AVCodecContext *avctx, PNGDecContext *s)
{
    if (s->state & PNG_IDAT) {
        av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
        return AVERROR_INVALIDDATA;
    }
    avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
    avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
    if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
        avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
    bytestream2_skip(&s->gb, 1); /* unit specifier */
    bytestream2_skip(&s->gb, 4); /* crc */

    return 0;
}

Project: FFmpeg
File: pngdec.c

static int decode_plte_chunk(AVCodecContext *avctx, PNGDecContext *s,
                             uint32_t length)
{
    int n, i, r, g, b;

    if ((length % 3) != 0 || length > 256 * 3)
        return AVERROR_INVALIDDATA;
    /* read the palette */
    n = length / 3;
    for (i = 0; i < n; i++) {
        r = bytestream2_get_byte(&s->gb);
        g = bytestream2_get_byte(&s->gb);
        b = bytestream2_get_byte(&s->gb);
        s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
    }
    for (; i < 256; i++)
        s->palette[i] = (0xFFU << 24);
    s->state |= PNG_PLTE;
    bytestream2_skip(&s->gb, 4);     /* crc */

    return 0;
}

Project: FFmpeg
File: pngdec.c

static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
                             AVDictionary **dict)
{
    int ret, method;
    const uint8_t *data        = s->gb.buffer;
    const uint8_t *data_end    = data + length;
    const uint8_t *keyword     = data;
    const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
    uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
    unsigned text_len;
    AVBPrint bp;

    if (!keyword_end)
        return AVERROR_INVALIDDATA;
    data = keyword_end + 1;

    if (compressed) {
        if (data == data_end)
            return AVERROR_INVALIDDATA;
        method = *(data++);
        if (method)
            return AVERROR_INVALIDDATA;
        if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
            return ret;
        text_len = bp.len;
        av_bprint_finalize(&bp, (char **)&text);
        if (!text)
            return AVERROR(ENOMEM);
    } else {
        text = (uint8_t *)data;
        text_len = data_end - text;
    }

    kw_utf8  = iso88591_to_utf8(keyword, keyword_end - keyword);
    txt_utf8 = iso88591_to_utf8(text, text_len);
    if (text != data)
        av_free(text);
    if (!(kw_utf8 && txt_utf8)) {
        av_free(kw_utf8);
        av_free(txt_utf8);
        return AVERROR(ENOMEM);
    }

    av_dict_set(dict, kw_utf8, txt_utf8,
                AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
    return 0;
}

Project: FFmpeg
File: pngdec.c

void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top,
                                 int w, int bpp)
{
    int i;
    for (i = 0; i < w; i++) {
        int a, b, c, p, pa, pb, pc;

        a = dst[i - bpp];
        b = top[i];
        c = top[i - bpp];

        p  = b - c;
        pc = a - c;

        pa = abs(p);
        pb = abs(pc);
        pc = abs(p + pc);

        if (pa <= pb && pa <= pc)
            p = a;
        else if (pb <= pc)
            p = b;
        else
            p = c;
        dst[i] = p + src[i];
    }
}

Project: FFmpeg
File: pngdec.c

static void handle_p_frame_png(PNGDecContext *s, AVFrame *p)
{
    int i, j;
    uint8_t *pd      = p->data[0];
    uint8_t *pd_last = s->last_picture.f->data[0];
    int ls = FFMIN(av_image_get_linesize(p->format, s->width, 0), s->width * s->bpp);

    ff_thread_await_progress(&s->last_picture, INT_MAX, 0);
    for (j = 0; j < s->height; j++) {
        for (i = 0; i < ls; i++)
            pd[i] += pd_last[i];
        pd      += s->image_linesize;
        pd_last += s->image_linesize;
    }
}

Project: FFmpeg
File: pngdec.c

static void handle_small_bpp(PNGDecContext *s, AVFrame *p)
{
    if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE) {
        int i, j, k;
        uint8_t *pd = p->data[0];
        for (j = 0; j < s->height; j++) {
            i = s->width / 8;
            for (k = 7; k >= 1; k--)
                if ((s->width&7) >= k)
                    pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
            for (i--; i >= 0; i--) {
                pd[8*i + 7]=  pd[i]     & 1;
                pd[8*i + 6]= (pd[i]>>1) & 1;
                pd[8*i + 5]= (pd[i]>>2) & 1;
                pd[8*i + 4]= (pd[i]>>3) & 1;
                pd[8*i + 3]= (pd[i]>>4) & 1;
                pd[8*i + 2]= (pd[i]>>5) & 1;
                pd[8*i + 1]= (pd[i]>>6) & 1;
                pd[8*i + 0]=  pd[i]>>7;
            }
            pd += s->image_linesize;
        }
    } else if (s->bits_per_pixel == 2) {
        int i, j;
        uint8_t *pd = p->data[0];
        for (j = 0; j < s->height; j++) {
            i = s->width / 4;
            if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
                if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
                if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
                if ((s->width&3) >= 1) pd[4*i + 0]=  pd[i] >> 6;
                for (i--; i >= 0; i--) {
                    pd[4*i + 3]=  pd[i]     & 3;
                    pd[4*i + 2]= (pd[i]>>2) & 3;
                    pd[4*i + 1]= (pd[i]>>4) & 3;
                    pd[4*i + 0]=  pd[i]>>6;
                }
            } else {
                if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
                if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
                if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6     )*0x55;
                for (i--; i >= 0; i--) {
                    pd[4*i + 3]= ( pd[i]     & 3)*0x55;
                    pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
                    pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
                    pd[4*i + 0]= ( pd[i]>>6     )*0x55;
                }
            }
            pd += s->image_linesize;
        }
    } else if (s->bits_per_pixel == 4) {
        int i, j;
        uint8_t *pd = p->data[0];
        for (j = 0; j < s->height; j++) {
            i = s->width/2;
            if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
                if (s->width&1) pd[2*i+0]= pd[i]>>4;
                for (i--; i >= 0; i--) {
                    pd[2*i + 1] = pd[i] & 15;
                    pd[2*i + 0] = pd[i] >> 4;
                }
            } else {
                if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
                for (i--; i >= 0; i--) {
                    pd[2*i + 1] = (pd[i] & 15) * 0x11;
                    pd[2*i + 0] = (pd[i] >> 4) * 0x11;
                }
            }
            pd += s->image_linesize;
        }
    }
}

Project: FFmpeg
File: pngdec.c

static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
{
    size_t extra = 0, i;
    uint8_t *out, *q;

    for (i = 0; i < size_in; i++)
        extra += in[i] >= 0x80;
    if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
        return NULL;
    q = out = av_malloc(size_in + extra + 1);
    if (!out)
        return NULL;
    for (i = 0; i < size_in; i++) {
        if (in[i] >= 0x80) {
            *(q++) = 0xC0 | (in[i] >> 6);
            *(q++) = 0x80 | (in[i] & 0x3F);
        } else {
            *(q++) = in[i];
        }
    }
    *(q++) = 0;
    return out;
}

Project: FFmpeg
File: pngdec.c

static av_cold int png_dec_end(AVCodecContext *avctx)
{
    PNGDecContext *s = avctx->priv_data;

    ff_thread_release_buffer(avctx, &s->previous_picture);
    av_frame_free(&s->previous_picture.f);
    ff_thread_release_buffer(avctx, &s->last_picture);
    av_frame_free(&s->last_picture.f);
    ff_thread_release_buffer(avctx, &s->picture);
    av_frame_free(&s->picture.f);
    av_freep(&s->buffer);
    s->buffer_size = 0;
    av_freep(&s->last_row);
    s->last_row_size = 0;
    av_freep(&s->tmp_row);
    s->tmp_row_size = 0;

    return 0;
}

Project: FFmpeg
File: pngdec.c

static av_cold int png_dec_init(AVCodecContext *avctx)
{
    PNGDecContext *s = avctx->priv_data;

    avctx->color_range = AVCOL_RANGE_JPEG;

    s->avctx = avctx;
    s->previous_picture.f = av_frame_alloc();
    s->last_picture.f = av_frame_alloc();
    s->picture.f = av_frame_alloc();
    if (!s->previous_picture.f || !s->last_picture.f || !s->picture.f) {
        av_frame_free(&s->previous_picture.f);
        av_frame_free(&s->last_picture.f);
        av_frame_free(&s->picture.f);
        return AVERROR(ENOMEM);
    }

    if (!avctx->internal->is_copy) {
        avctx->internal->allocate_progress = 1;
        ff_pngdsp_init(&s->dsp);
    }

    return 0;
}

Project: FFmpeg
File: pngdec.c

static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
                           uint8_t *src, uint8_t *last, int size, int bpp)
{
    int i, p, r, g, b, a;

    switch (filter_type) {
    case PNG_FILTER_VALUE_NONE:
        memcpy(dst, src, size);
        break;
    case PNG_FILTER_VALUE_SUB:
        for (i = 0; i < bpp; i++)
            dst[i] = src[i];
        if (bpp == 4) {
            p = *(int *)dst;
            for (; i < size; i += bpp) {
                unsigned s = *(int *)(src + i);
                p = ((s & 0x7f7f7f7f) + (p & 0x7f7f7f7f)) ^ ((s ^ p) & 0x80808080);
                *(int *)(dst + i) = p;
            }
        } else {
#define OP_SUB(x, s, l) ((x) + (s))
            UNROLL_FILTER(OP_SUB);
        }
        break;
    case PNG_FILTER_VALUE_UP:
        dsp->add_bytes_l2(dst, src, last, size);
        break;
    case PNG_FILTER_VALUE_AVG:
        for (i = 0; i < bpp; i++) {
            p      = (last[i] >> 1);
            dst[i] = p + src[i];
        }
#define OP_AVG(x, s, l) (((((x) + (l)) >> 1) + (s)) & 0xff)
        UNROLL_FILTER(OP_AVG);
        break;
    case PNG_FILTER_VALUE_PAETH:
        for (i = 0; i < bpp; i++) {
            p      = last[i];
            dst[i] = p + src[i];
        }
        if (bpp > 2 && size > 4) {
            /* would write off the end of the array if we let it process
             * the last pixel with bpp=3 */
            int w = (bpp & 3) ? size - 3 : size;

            if (w > i) {
                dsp->add_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
                i = w;
            }
        }
        ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
        break;
    }
}

Project: FFmpeg
File: pngdec.c

static void png_handle_row(PNGDecContext *s)
{
    uint8_t *ptr, *last_row;
    int got_line;

    if (!s->interlace_type) {
        ptr = s->image_buf + s->image_linesize * (s->y + s->y_offset) + s->x_offset * s->bpp;
        if (s->y == 0)
            last_row = s->last_row;
        else
            last_row = ptr - s->image_linesize;

        png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
                       last_row, s->row_size, s->bpp);
        /* loco lags by 1 row so that it doesn't interfere with top prediction */
        if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
            if (s->bit_depth == 16) {
                deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
                             s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
            } else {
                deloco_rgb8(ptr - s->image_linesize, s->row_size,
                            s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
            }
        }
        s->y++;
        if (s->y == s->cur_h) {
            s->state |= PNG_ALLIMAGE;
            if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
                if (s->bit_depth == 16) {
                    deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
                                 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
                } else {
                    deloco_rgb8(ptr, s->row_size,
                                s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
                }
            }
        }
    } else {
        got_line = 0;
        for (;;) {
            ptr = s->image_buf + s->image_linesize * (s->y + s->y_offset) + s->x_offset * s->bpp;
            if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
                /* if we already read one row, it is time to stop to
                 * wait for the next one */
                if (got_line)
                    break;
                png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
                               s->last_row, s->pass_row_size, s->bpp);
                FFSWAP(uint8_t *, s->last_row, s->tmp_row);
                FFSWAP(unsigned int, s->last_row_size, s->tmp_row_size);
                got_line = 1;
            }
            if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
                png_put_interlaced_row(ptr, s->cur_w, s->bits_per_pixel, s->pass,
                                       s->color_type, s->last_row);
            }
            s->y++;
            if (s->y == s->cur_h) {
                memset(s->last_row, 0, s->row_size);
                for (;;) {
                    if (s->pass == NB_PASSES - 1) {
                        s->state |= PNG_ALLIMAGE;
                        goto the_end;
                    } else {
                        s->pass++;
                        s->y = 0;
                        s->pass_row_size = ff_png_pass_row_size(s->pass,
                                                                s->bits_per_pixel,
                                                                s->cur_w);
                        s->crow_size = s->pass_row_size + 1;
                        if (s->pass_row_size != 0)
                            break;
                        /* skip pass if empty row */
                    }
                }
            }
        }
the_end:;
    }
}

Project: FFmpeg
File: pngdec.c

static void png_put_interlaced_row(uint8_t *dst, int width,
                                   int bits_per_pixel, int pass,
                                   int color_type, const uint8_t *src)
{
    int x, mask, dsp_mask, j, src_x, b, bpp;
    uint8_t *d;
    const uint8_t *s;

    mask     = png_pass_mask[pass];
    dsp_mask = png_pass_dsp_mask[pass];

    switch (bits_per_pixel) {
    case 1:
        src_x = 0;
        for (x = 0; x < width; x++) {
            j = (x & 7);
            if ((dsp_mask << j) & 0x80) {
                b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
                dst[x >> 3] &= 0xFF7F>>j;
                dst[x >> 3] |= b << (7 - j);
            }
            if ((mask << j) & 0x80)
                src_x++;
        }
        break;
    case 2:
        src_x = 0;
        for (x = 0; x < width; x++) {
            int j2 = 2 * (x & 3);
            j = (x & 7);
            if ((dsp_mask << j) & 0x80) {
                b = (src[src_x >> 2] >> (6 - 2*(src_x & 3))) & 3;
                dst[x >> 2] &= 0xFF3F>>j2;
                dst[x >> 2] |= b << (6 - j2);
            }
            if ((mask << j) & 0x80)
                src_x++;
        }
        break;
    case 4:
        src_x = 0;
        for (x = 0; x < width; x++) {
            int j2 = 4*(x&1);
            j = (x & 7);
            if ((dsp_mask << j) & 0x80) {
                b = (src[src_x >> 1] >> (4 - 4*(src_x & 1))) & 15;
                dst[x >> 1] &= 0xFF0F>>j2;
                dst[x >> 1] |= b << (4 - j2);
            }
            if ((mask << j) & 0x80)
                src_x++;
        }
        break;
    default:
        bpp = bits_per_pixel >> 3;
        d   = dst;
        s   = src;
            for (x = 0; x < width; x++) {
                j = x & 7;
                if ((dsp_mask << j) & 0x80) {
                    memcpy(d, s, bpp);
                }
                d += bpp;
                if ((mask << j) & 0x80)
                    s += bpp;
            }
        break;
    }
}

Project: FFmpeg
File: pngdec.c

static int update_thread_context(AVCodecContext *dst, const AVCodecContext *src)
{
    PNGDecContext *psrc = src->priv_data;
    PNGDecContext *pdst = dst->priv_data;
    int ret;

    if (dst == src)
        return 0;

    ff_thread_release_buffer(dst, &pdst->picture);
    if (psrc->picture.f->data[0] &&
        (ret = ff_thread_ref_frame(&pdst->picture, &psrc->picture)) < 0)
        return ret;
    if (CONFIG_APNG_DECODER && dst->codec_id == AV_CODEC_ID_APNG) {
        pdst->width             = psrc->width;
        pdst->height            = psrc->height;
        pdst->bit_depth         = psrc->bit_depth;
        pdst->color_type        = psrc->color_type;
        pdst->compression_type  = psrc->compression_type;
        pdst->interlace_type    = psrc->interlace_type;
        pdst->filter_type       = psrc->filter_type;
        pdst->cur_w = psrc->cur_w;
        pdst->cur_h = psrc->cur_h;
        pdst->x_offset = psrc->x_offset;
        pdst->y_offset = psrc->y_offset;
        pdst->has_trns = psrc->has_trns;
        memcpy(pdst->transparent_color_be, psrc->transparent_color_be, sizeof(pdst->transparent_color_be));

        pdst->dispose_op = psrc->dispose_op;

        memcpy(pdst->palette, psrc->palette, sizeof(pdst->palette));

        pdst->state |= psrc->state & (PNG_IHDR | PNG_PLTE);

        ff_thread_release_buffer(dst, &pdst->last_picture);
        if (psrc->last_picture.f->data[0] &&
            (ret = ff_thread_ref_frame(&pdst->last_picture, &psrc->last_picture)) < 0)
            return ret;

        ff_thread_release_buffer(dst, &pdst->previous_picture);
        if (psrc->previous_picture.f->data[0] &&
            (ret = ff_thread_ref_frame(&pdst->previous_picture, &psrc->previous_picture)) < 0)
            return ret;
    }

    return 0;
}