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math: auditory: guard mod_psy_get_mel_filterbank() against zero divisors #10916

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math: auditory: guard mod_psy_get_mel_filterbank() against zero divisors #10916

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1 change: 1 addition & 0 deletions src/include/sof/math/auditory.h
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@
#include <sof/math/log.h>
#include <stdint.h>

#define AUDITORY_MAX_MEL_BANDS 256
#define AUDITORY_EPS_Q31 1 /* Smallest nonzero Q1.31 value */
#define AUDITORY_LOG2_2P25_Q16 Q_CONVERT_FLOAT(25.0, 16) /* log2(2^25) */

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29 changes: 29 additions & 0 deletions src/math/auditory/auditory.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12,10 +12,13 @@
#include <sof/math/fft.h>
#include <sof/math/log.h>
#include <sof/math/numbers.h>
#include <sof/trace/trace.h>
#include <ipc/topology.h>
#include <errno.h>
#include <stdint.h>

LOG_MODULE_REGISTER(math_auditory, CONFIG_SOF_LOG_LEVEL);

#define ONE_Q16 Q_CONVERT_FLOAT(1, 16)
#define ONE_Q20 Q_CONVERT_FLOAT(1, 20)
#define ONE_Q30 Q_CONVERT_FLOAT(1, 30)
Expand Down Expand Up @@ -117,6 +120,16 @@ int mod_psy_get_mel_filterbank(struct processing_module *mod, struct psy_mel_fil
if (!fb->scratch_data1 || !fb->scratch_data2)
return -ENOMEM;

/* fb->mel_bins is used both as the loop bound and as part of the
* (mel_bins + 1) divisor below. Reject non-positive values up front to
* avoid a divide by zero (mel_bins == -1) and to keep mel_step
* meaningful.
*/
if (fb->mel_bins <= 0 || fb->mel_bins > AUDITORY_MAX_MEL_BANDS) {
comp_cl_err(mod->dev, "Invalid mel_bins %d", fb->mel_bins);
return -EINVAL;
}

/* Log power can be log, or log10 or dB, get multiply coef to convert
* log to desired format.
*/
Expand Down Expand Up @@ -149,6 +162,17 @@ int mod_psy_get_mel_filterbank(struct processing_module *mod, struct psy_mel_fil
mel_start = psy_hz_to_mel(fb->start_freq);
mel_end = psy_hz_to_mel(fb->end_freq);
mel_step = (mel_end - mel_start) / (fb->mel_bins + 1);
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/* delta_cl / delta_rc below are both equal to mel_step; guard against
* a non-positive step (start_freq >= end_freq, or so many bins that
* the integer division truncates to zero) before using them as
* divisors.
*/
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if (mel_step <= 0) {
comp_cl_err(mod->dev, "Invalid mel_step %d (start_freq=%d end_freq=%d mel_bins=%d)",
mel_step, fb->start_freq, fb->end_freq, fb->mel_bins);
return -EINVAL;
}
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for (i = 0; i < fb->mel_bins; i++) {
left_mel = mel_start + i * mel_step;
center_mel = mel_start + (i + 1) * mel_step;
Comment on lines 176 to 178

@singalsu singalsu Jun 15, 2026

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Won't do, not relevant.

Expand All @@ -160,6 +184,11 @@ int mod_psy_get_mel_filterbank(struct processing_module *mod, struct psy_mel_fil
if (fb->slaney_normalize) {
left_hz = psy_mel_to_hz(left_mel);
right_hz = psy_mel_to_hz(right_mel);
if (right_hz <= left_hz) {
comp_cl_err(mod->dev, "Invalid Hz range left=%d right=%d at mel bin %d",
left_hz, right_hz, i);
return -EINVAL;
}
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scale = Q_SHIFT_RND(TWO_Q29 / (right_hz - left_hz), 29, 16); /* Q16.16*/
if (i == 0) {
scale_inv = Q_SHIFT_LEFT(ONE_Q30 / scale, 14, 16);
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