bmv: fix integer overflows in vlc decoder.
Fixes part of Ticket1373
Found-by: Piotr Bandurski <ami_stuff@o2.pl>
Based-on-patch-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 679c578cb8)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
			
			
This commit is contained in:
		@@ -21,6 +21,7 @@
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#include "avcodec.h"
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#include "bytestream.h"
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#include "libavutil/avassert.h"
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enum BMVFlags{
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    BMV_NOP = 0,
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@@ -52,7 +53,7 @@ typedef struct BMVDecContext {
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static int decode_bmv_frame(const uint8_t *source, int src_len, uint8_t *frame, int frame_off)
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{
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    int val, saved_val = 0;
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    unsigned val, saved_val = 0;
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    int tmplen = src_len;
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    const uint8_t *src, *source_end = source + src_len;
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    uint8_t *frame_end = frame + SCREEN_WIDE * SCREEN_HIGH;
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@@ -98,6 +99,8 @@ static int decode_bmv_frame(const uint8_t *source, int src_len, uint8_t *frame,
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        }
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        if (!(val & 0xC)) {
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            for (;;) {
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                if(shift>22)
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                    return -1;
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                if (!read_two_nibbles) {
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                    if (src < source || src >= source_end)
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                        return -1;
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@@ -131,6 +134,7 @@ static int decode_bmv_frame(const uint8_t *source, int src_len, uint8_t *frame,
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        }
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        advance_mode = val & 1;
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        len = (val >> 1) - 1;
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        av_assert0(len>0);
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        mode += 1 + advance_mode;
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        if (mode >= 4)
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            mode -= 3;
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