golomb: always check for invalid UE golomb codes in get_ue_golomb
Also correct the check to reject log < 7, because UPDATE_CACHE only guarantees 25 meaningful bits. This fixes undefined behavior: runtime error: shift exponent is negative Testing with START/STOP timers in get_ue_golomb, one for the first branch (A) and one for the second (B), shows that there is practically no slowdown, e.g. for the cavs decoder: With the check in the B branch: 629 decicycles in get_ue_golomb B, 4194260 runs, 44 skips 433 decicycles in get_ue_golomb A,268434102 runs, 1354 skips Without the check: 624 decicycles in get_ue_golomb B, 4194273 runs, 31 skips 433 decicycles in get_ue_golomb A,268434203 runs, 1253 skips Since the B branch is executed far less often than the A branch, this change is negligible, even more so for the h264 decoder, where the ratio B/A is a lot smaller. Fixes: mozilla bug 1230239 Fixes: fbeb8b2c7c996e9b91c6b1af319d7ebc/asan_heap-oob_195450f_2743_e8856ece4579ea486670be2b236099a0.bit Found-by: Tyson Smith Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind Reviewed-by: Michael Niedermayer <michael@niedermayer.cc> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
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