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avcodec/bitstream: Check code length before truncating to uint8_t 

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2020-10-24 14:11:14 +02:00
parent e5be4c5a88
commit e75b6ec43b
1 changed files with 7 additions and 5 deletions
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12
libavcodec/bitstream.c
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@ -302,15 +302,17 @@ int ff_init_vlc_sparse(VLC *vlc_arg, int nb_bits, int nb_codes,
j = 0;
#define COPY(condition)\
for (i = 0; i < nb_codes; i++) { \
GET_DATA(buf[j].bits, bits, i, bits_wrap, bits_size); \
unsigned len; \
GET_DATA(len, bits, i, bits_wrap, bits_size); \
if (!(condition)) \
continue; \
if (buf[j].bits > 3*nb_bits || buf[j].bits>32) { \
av_log(NULL, AV_LOG_ERROR, "Too long VLC (%d) in init_vlc\n", buf[j].bits);\
if (len > 3*nb_bits || len > 32) { \
av_log(NULL, AV_LOG_ERROR, "Too long VLC (%u) in init_vlc\n", len);\
if (buf != localbuf) \
av_free(buf); \
return AVERROR(EINVAL); \
} \
buf[j].bits = len; \
GET_DATA(buf[j].code, codes, i, codes_wrap, codes_size); \
if (buf[j].code >= (1LL<<buf[j].bits)) { \
av_log(NULL, AV_LOG_ERROR, "Invalid code %"PRIx32" for %d in " \
@ -329,10 +331,10 @@ int ff_init_vlc_sparse(VLC *vlc_arg, int nb_bits, int nb_codes,
buf[j].symbol = i; \
j++; \
}
COPY(buf[j].bits > nb_bits);
COPY(len > nb_bits);
// qsort is the slowest part of init_vlc, and could probably be improved or avoided
AV_QSORT(buf, j, struct VLCcode, compare_vlcspec);
COPY(buf[j].bits && buf[j].bits <= nb_bits);
COPY(len && len <= nb_bits);
nb_codes = j;
ret = build_table(vlc, nb_bits, nb_codes, buf, flags);