diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c index b60b2a0238..d5ad14e9bc 100644 --- a/libavcodec/pngdec.c +++ b/libavcodec/pngdec.c @@ -809,6 +809,7 @@ 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; @@ -819,23 +820,23 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s, } sequence_number = bytestream2_get_be32(&s->gb); - s->cur_w = bytestream2_get_be32(&s->gb); - s->cur_h = bytestream2_get_be32(&s->gb); - s->x_offset = bytestream2_get_be32(&s->gb); - s->y_offset = 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) */ - s->dispose_op = bytestream2_get_byte(&s->gb); - s->blend_op = bytestream2_get_byte(&s->gb); + dispose_op = bytestream2_get_byte(&s->gb); + blend_op = bytestream2_get_byte(&s->gb); bytestream2_skip(&s->gb, 4); /* crc */ if (sequence_number == 0 && - (s->cur_w != s->width || - s->cur_h != s->height || - s->x_offset != 0 || - s->y_offset != 0) || - s->cur_w <= 0 || s->cur_h <= 0 || - s->x_offset < 0 || s->y_offset < 0 || - s->cur_w > s->width - s->x_offset|| s->cur_h > s->height - s->y_offset) + (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; /* always (re)start with a clean frame */ @@ -849,6 +850,13 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s, s->dispose_op = APNG_DISPOSE_OP_NONE; } + 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; }