resampler: Make sure that there are no overflows when multiplying potentially big numbers.

This fixes at least one crash that has been observed. The
multiplication in trivial_resample() overflowed when
resampling from 96 kHz to 48 kHz, causing an assertion
error:

Assertion 'o_index * fz < pa_memblock_get_length(output->memblock)' failed at pulsecore/resampler.c:1521, function trivial_resample(). Aborting.

Without the assertion, the memcpy() after the assertion
would have overwritten some random heap memory.
This commit is contained in:
Tanu Kaskinen 2012-07-09 10:07:05 +03:00
parent 9bcb9f1a62
commit e4adf9c4d8

View file

@ -389,7 +389,7 @@ size_t pa_resampler_request(pa_resampler *r, size_t out_length) {
* loops. When the leftover is ignored here, such loops would eventually * loops. When the leftover is ignored here, such loops would eventually
* terminate, because the leftover would grow each round, finally * terminate, because the leftover would grow each round, finally
* surpassing the minimum input threshold of the resampler. */ * surpassing the minimum input threshold of the resampler. */
return (((((out_length + r->o_fz-1) / r->o_fz) * r->i_ss.rate) + r->o_ss.rate-1) / r->o_ss.rate) * r->i_fz; return ((((uint64_t) ((out_length + r->o_fz-1) / r->o_fz) * r->i_ss.rate) + r->o_ss.rate-1) / r->o_ss.rate) * r->i_fz;
} }
size_t pa_resampler_result(pa_resampler *r, size_t in_length) { size_t pa_resampler_result(pa_resampler *r, size_t in_length) {
@ -405,7 +405,7 @@ size_t pa_resampler_result(pa_resampler *r, size_t in_length) {
if (r->remap_buf_contains_leftover_data) if (r->remap_buf_contains_leftover_data)
frames += r->remap_buf.length / (r->w_sz * r->o_ss.channels); frames += r->remap_buf.length / (r->w_sz * r->o_ss.channels);
return ((frames * r->o_ss.rate + r->i_ss.rate - 1) / r->i_ss.rate) * r->o_fz; return (((uint64_t) frames * r->o_ss.rate + r->i_ss.rate - 1) / r->i_ss.rate) * r->o_fz;
} }
size_t pa_resampler_max_block_size(pa_resampler *r) { size_t pa_resampler_max_block_size(pa_resampler *r) {
@ -434,7 +434,7 @@ size_t pa_resampler_max_block_size(pa_resampler *r) {
if (r->remap_buf_contains_leftover_data) if (r->remap_buf_contains_leftover_data)
frames -= r->remap_buf.length / (r->w_sz * r->o_ss.channels); frames -= r->remap_buf.length / (r->w_sz * r->o_ss.channels);
return (frames * r->i_ss.rate / max_ss.rate) * r->i_fz; return ((uint64_t) frames * r->i_ss.rate / max_ss.rate) * r->i_fz;
} }
void pa_resampler_reset(pa_resampler *r) { void pa_resampler_reset(pa_resampler *r) {
@ -1519,7 +1519,7 @@ static void trivial_resample(pa_resampler *r, const pa_memchunk *input, unsigned
dst = pa_memblock_acquire_chunk(output); dst = pa_memblock_acquire_chunk(output);
for (o_index = 0;; o_index++, r->trivial.o_counter++) { for (o_index = 0;; o_index++, r->trivial.o_counter++) {
i_index = (r->trivial.o_counter * r->i_ss.rate) / r->o_ss.rate; i_index = ((uint64_t) r->trivial.o_counter * r->i_ss.rate) / r->o_ss.rate;
i_index = i_index > r->trivial.i_counter ? i_index - r->trivial.i_counter : 0; i_index = i_index > r->trivial.i_counter ? i_index - r->trivial.i_counter : 0;
if (i_index >= in_n_frames) if (i_index >= in_n_frames)
@ -1580,11 +1580,11 @@ static void peaks_resample(pa_resampler *r, const pa_memchunk *input, unsigned i
src = pa_memblock_acquire_chunk(input); src = pa_memblock_acquire_chunk(input);
dst = pa_memblock_acquire_chunk(output); dst = pa_memblock_acquire_chunk(output);
i = (r->peaks.o_counter * r->i_ss.rate) / r->o_ss.rate; i = ((uint64_t) r->peaks.o_counter * r->i_ss.rate) / r->o_ss.rate;
i = i > r->peaks.i_counter ? i - r->peaks.i_counter : 0; i = i > r->peaks.i_counter ? i - r->peaks.i_counter : 0;
while (i_end < in_n_frames) { while (i_end < in_n_frames) {
i_end = ((r->peaks.o_counter+1) * r->i_ss.rate) / r->o_ss.rate; i_end = ((uint64_t) (r->peaks.o_counter + 1) * r->i_ss.rate) / r->o_ss.rate;
i_end = i_end > r->peaks.i_counter ? i_end - r->peaks.i_counter : 0; i_end = i_end > r->peaks.i_counter ? i_end - r->peaks.i_counter : 0;
pa_assert_fp(o_index * r->w_sz * r->o_ss.channels < pa_memblock_get_length(output->memblock)); pa_assert_fp(o_index * r->w_sz * r->o_ss.channels < pa_memblock_get_length(output->memblock));