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pcx: Do not overread source buffer in pcx_rle_decode
Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind CC: libav-stable@libav.org
This commit is contained in:
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170fb593c6
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3abde1a3b4
@ -31,7 +31,9 @@
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/**
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* @return advanced src pointer
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*/
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static const uint8_t *pcx_rle_decode(const uint8_t *src, uint8_t *dst,
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static const uint8_t *pcx_rle_decode(const uint8_t *src,
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const uint8_t *end,
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uint8_t *dst,
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unsigned int bytes_per_scanline,
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int compressed)
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{
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@ -39,10 +41,10 @@ static const uint8_t *pcx_rle_decode(const uint8_t *src, uint8_t *dst,
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unsigned char run, value;
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if (compressed) {
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while (i < bytes_per_scanline) {
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while (i < bytes_per_scanline && src < end) {
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run = 1;
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value = *src++;
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if (value >= 0xc0) {
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if (value >= 0xc0 && src < end) {
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run = value & 0x3f;
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value = *src++;
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}
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@ -78,6 +80,7 @@ static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
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unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
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bytes_per_scanline;
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uint8_t *ptr;
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const uint8_t *buf_end = buf + buf_size;
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uint8_t const *bufstart = buf;
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uint8_t *scanline;
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int ret = -1;
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@ -106,7 +109,8 @@ static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
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nplanes = buf[65];
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bytes_per_scanline = nplanes * bytes_per_line;
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if (bytes_per_scanline < w * bits_per_pixel * nplanes / 8) {
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if (bytes_per_scanline < w * bits_per_pixel * nplanes / 8 ||
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(!compressed && bytes_per_scanline > buf_size / h)) {
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av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
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return AVERROR_INVALIDDATA;
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}
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@ -151,7 +155,8 @@ static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
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if (nplanes == 3 && bits_per_pixel == 8) {
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for (y = 0; y < h; y++) {
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buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
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buf = pcx_rle_decode(buf, buf_end,
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scanline, bytes_per_scanline, compressed);
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for (x = 0; x < w; x++) {
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ptr[3 * x] = scanline[x];
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@ -165,7 +170,8 @@ static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
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const uint8_t *palstart = bufstart + buf_size - 769;
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for (y = 0; y < h; y++, ptr += stride) {
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buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
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buf = pcx_rle_decode(buf, buf_end,
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scanline, bytes_per_scanline, compressed);
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memcpy(ptr, scanline, w);
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}
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@ -183,7 +189,8 @@ static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
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for (y = 0; y < h; y++) {
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init_get_bits(&s, scanline, bytes_per_scanline << 3);
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buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
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buf = pcx_rle_decode(buf, buf_end,
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scanline, bytes_per_scanline, compressed);
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for (x = 0; x < w; x++)
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ptr[x] = get_bits(&s, bits_per_pixel);
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@ -193,7 +200,8 @@ static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
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int i;
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for (y = 0; y < h; y++) {
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buf = pcx_rle_decode(buf, scanline, bytes_per_scanline, compressed);
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buf = pcx_rle_decode(buf, buf_end,
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scanline, bytes_per_scanline, compressed);
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for (x = 0; x < w; x++) {
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int m = 0x80 >> (x & 7), v = 0;
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