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avcodec/g729postfilter: Optimize out overflowing multiplication from apply_tilt_comp() 

Fixes: signed integer overflow: -1114392282 * 2 cannot be represented in type 'int'
Fixes: 19236/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_G729_fuzzer-5741678938030080

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-12-07 20:38:13 +01:00
parent fea90e9438
commit c0bd5fa43d
1 changed files with 7 additions and 7 deletions
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14
libavcodec/g729postfilter.c
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@ -486,14 +486,14 @@ static int16_t apply_tilt_comp(int16_t* out, int16_t* res_pst, int refl_coeff,
if (refl_coeff > 0) { if (refl_coeff > 0) {
gt = (refl_coeff * G729_TILT_FACTOR_PLUS + 0x4000) >> 15; gt = (refl_coeff * G729_TILT_FACTOR_PLUS + 0x4000) >> 15;
fact = 0x4000; // 0.5 in (0.15) fact = 0x2000; // 0.5 in (0.15)
sh_fact = 15; sh_fact = 14;
} else { } else {
gt = (refl_coeff * G729_TILT_FACTOR_MINUS + 0x4000) >> 15; gt = (refl_coeff * G729_TILT_FACTOR_MINUS + 0x4000) >> 15;
fact = 0x800; // 0.5 in (3.12) fact = 0x400; // 0.5 in (3.12)
sh_fact = 12; sh_fact = 11;
} }
ga = (fact << 15) / av_clip_int16(32768 - FFABS(gt)); ga = (fact << 16) / av_clip_int16(32768 - FFABS(gt));
gt >>= 1; gt >>= 1;
/* Apply tilt compensation filter to signal. */ /* Apply tilt compensation filter to signal. */
@ -503,12 +503,12 @@ static int16_t apply_tilt_comp(int16_t* out, int16_t* res_pst, int refl_coeff,
tmp2 = (gt * res_pst[i-1]) * 2 + 0x4000; tmp2 = (gt * res_pst[i-1]) * 2 + 0x4000;
tmp2 = res_pst[i] + (tmp2 >> 15); tmp2 = res_pst[i] + (tmp2 >> 15);
tmp2 = (tmp2 * ga * 2 + fact) >> sh_fact; tmp2 = (tmp2 * ga + fact) >> sh_fact;
out[i] = tmp2; out[i] = tmp2;
} }
tmp2 = (gt * ht_prev_data) * 2 + 0x4000; tmp2 = (gt * ht_prev_data) * 2 + 0x4000;
tmp2 = res_pst[0] + (tmp2 >> 15); tmp2 = res_pst[0] + (tmp2 >> 15);
tmp2 = (tmp2 * ga * 2 + fact) >> sh_fact; tmp2 = (tmp2 * ga + fact) >> sh_fact;
out[0] = tmp2; out[0] = tmp2;
return tmp; return tmp;