virtualenv/FFmpeg
1
0
Fork 0
mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-11-21 10:55:51 +02:00
Code Issues Releases Activity

avcodec/sbrdsp_fixed: Fix assertion failure in sbr_sum_square_c()

Browse Source 
This also increases the range of input values supported as well as
decreasing the operation dependencies in the main loop, improving
speed on modern CPUs.

Fixes part of: 2045/clusterfuzz-testcase-minimized-6751255865065472

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 2017-06-04 20:54:44 +02:00
parent 6019d721d4
commit b315a3cf42
1 changed files with 27 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
libavcodec/sbrdsp_fixed.c
View File

@ -34,38 +34,47 @@
static SoftFloat sbr_sum_square_c(int (*x)[2], int n)
{
SoftFloat ret;
uint64_t accu = 0, round;
int i, nz;
uint64_t accu, round;
uint64_t accu0 = 0, accu1 = 0, accu2 = 0, accu3 = 0;
int i, nz, nz0;
unsigned u;
for (i = 0; i < n; i += 2) {
// Larger values are inavlid and could cause overflows of accu.
av_assert2(FFABS(x[i + 0][0]) >> 29 == 0);
accu += (int64_t)x[i + 0][0] * x[i + 0][0];
av_assert2(FFABS(x[i + 0][1]) >> 29 == 0);
accu += (int64_t)x[i + 0][1] * x[i + 0][1];
av_assert2(FFABS(x[i + 1][0]) >> 29 == 0);
accu += (int64_t)x[i + 1][0] * x[i + 1][0];
av_assert2(FFABS(x[i + 1][1]) >> 29 == 0);
accu += (int64_t)x[i + 1][1] * x[i + 1][1];
av_assert2(FFABS(x[i + 0][0]) >> 30 == 0);
accu0 += (int64_t)x[i + 0][0] * x[i + 0][0];
av_assert2(FFABS(x[i + 0][1]) >> 30 == 0);
accu1 += (int64_t)x[i + 0][1] * x[i + 0][1];
av_assert2(FFABS(x[i + 1][0]) >> 30 == 0);
accu2 += (int64_t)x[i + 1][0] * x[i + 1][0];
av_assert2(FFABS(x[i + 1][1]) >> 30 == 0);
accu3 += (int64_t)x[i + 1][1] * x[i + 1][1];
}
nz0 = 15;
while ((accu0|accu1|accu2|accu3) >> 62) {
accu0 >>= 1;
accu1 >>= 1;
accu2 >>= 1;
accu3 >>= 1;
nz0 --;
}
accu = accu0 + accu1 + accu2 + accu3;
u = accu >> 32;
if (u == 0) {
nz = 1;
} else {
nz = -1;
if (u) {
nz = 33;
while (u < 0x80000000U) {
u <<= 1;
nz++;
nz--;
}
nz = 32 - nz;
}
} else
nz = 1;
round = 1ULL << (nz-1);
u = ((accu + round) >> nz);
u >>= 1;
ret = av_int2sf(u, 15 - nz);
ret = av_int2sf(u, nz0 - nz);
return ret;
}