Backport of upstream commit bedfb6eca402037f5cbb115fa767d106b8c14f1c to release/5.0.
The 5.0 branch is still affected by CVE-2025-1594. The upstream patch does not apply cleanly due to code differences, so this patch manually adapts the fix while preserving the original logic. A crafted input can trigger a stack-based buffer overflow in ff_aac_search_for_tns. Reproducer triggers a crash before the patch is applied, and works as expected after applying the patch. Associated issue: https://code.ffmpeg.org/FFmpeg/FFmpeg/issues/22696 CVE: CVE-2025-1594 Found-by: 0x20z Signed-off-by: lizhixuan.HUST <[email protected]> --- libavcodec/aacenc_tns.c | 33 ++++++++++++++++++++++++--------- 1 file changed, 24 insertions(+), 9 deletions(-) diff --git a/libavcodec/aacenc_tns.c b/libavcodec/aacenc_tns.c index 2ffe1f8de8..c203c5662b 100644 --- a/libavcodec/aacenc_tns.c +++ b/libavcodec/aacenc_tns.c @@ -173,6 +173,7 @@ void ff_aac_search_for_tns(AACEncContext *s, SingleChannelElement *sce) sce->ics.window_sequence[0] == LONG_START_SEQUENCE ? 0 : 2; const int sfb_len = sfb_end - sfb_start; const int coef_len = sce->ics.swb_offset[sfb_end] - sce->ics.swb_offset[sfb_start]; + const int n_filt = is8 ? 1 : order != TNS_MAX_ORDER ? 2 : 3; if (coef_len <= 0 || sfb_len <= 0) { sce->tns.present = 0; @@ -180,16 +181,30 @@ void ff_aac_search_for_tns(AACEncContext *s, SingleChannelElement *sce) } for (w = 0; w < sce->ics.num_windows; w++) { - float en[2] = {0.0f, 0.0f}; + float en[4] = {0.0f, 0.0f, 0.0f, 0.0f}; int oc_start = 0, os_start = 0; int coef_start = sce->ics.swb_offset[sfb_start]; - for (g = sfb_start; g < sce->ics.num_swb && g <= sfb_end; g++) { - FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[w*16+g]; - if (g > sfb_start + (sfb_len/2)) - en[1] += band->energy; - else - en[0] += band->energy; + if (n_filt == 2) { + for (g = sfb_start; g < sce->ics.num_swb && g <= sfb_end; g++) { + FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[w*16+g]; + if (g > sfb_start + (sfb_len/2)) + en[1] += band->energy; /* End */ + else + en[0] += band->energy; /* Start */ + } + en[2] = en[0]; + } else { + for (g = sfb_start; g < sce->ics.num_swb && g <= sfb_end; g++) { + FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[w*16+g]; + if (g > sfb_start + (sfb_len/2) + (sfb_len/4)) + en[2] += band->energy; /* End */ + else if (g > sfb_start + (sfb_len/2) - (sfb_len/4)) + en[1] += band->energy; /* Middle */ + else + en[0] += band->energy; /* Start */ + } + en[3] = en[0]; } /* LPC */ @@ -199,9 +214,9 @@ void ff_aac_search_for_tns(AACEncContext *s, SingleChannelElement *sce) if (!order || !isfinite(gain) || gain < TNS_GAIN_THRESHOLD_LOW || gain > TNS_GAIN_THRESHOLD_HIGH) continue; - tns->n_filt[w] = is8 ? 1 : order != TNS_MAX_ORDER ? 2 : 3; + tns->n_filt[w] = n_filt; for (g = 0; g < tns->n_filt[w]; g++) { - tns->direction[w][g] = slant != 2 ? slant : en[g] < en[!g]; + tns->direction[w][g] = slant != 2 ? slant : en[g] < en[g + 1]; tns->order[w][g] = g < tns->n_filt[w] ? order/tns->n_filt[w] : order - oc_start; tns->length[w][g] = g < tns->n_filt[w] ? sfb_len/tns->n_filt[w] : sfb_len - os_start; quantize_coefs(&coefs[oc_start], tns->coef_idx[w][g], tns->coef[w][g], -- 2.34.1 _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
