[libopenapv] Fix signed overflow in VLC decoding#213
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Add bounds checks to prevent signed integer overflow during VLC decoding. 1. In dec_vlc_read_1bit_read, limit the number of leading zeros (k) to < 30 to prevent overflow when calculating symbol and suffix. 2. In dec_vlc_read, limit k to < 31 in the exp-golomb loop to prevent signed overflow in the shift operation (1 << k). 3. Update KPARAM_AC macro in oapv_vlc.h to use oapv_clip3 instead of oapv_min, ensuring the returned parameter is always >= 0. This prevents a crash in media.swcodec when processing malformed bitstreams with excessive zeros. Bug: 495077878 Test: manual verification with stagefright and PoC Flag: EXEMPT BUGFIX Change-Id: Ia44c26d6a012681d94873bb1bcd372008c8b5bda
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@kpchoi please review |
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Add bounds checking to BSW_FLUSH_4BYTE and BSW_FLUSH_8BYTE macros in oapv_vlc.c to prevent writing past the end of the bitstream buffer during VLC encoding.
Add bounds checking in enc_frame in oapv.c to ensure the cumulative tile bitstream size does not exceed the target bitstream buffer end before copying tile bitstreams.
Change-Id: Ib40bc500096b6fda93e5802d97b306e4320ba6eb