[PATCH 6.6.y 2/2] ASoC: SOF: ipc4-topology: Harden loops for looking up ALH copiers

[Artem Dinaburg <artem@trailofbits.com>]

From: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

[ Upstream commit 6fd60136d256b3b948333ebdb3835f41a95ab7ef ]

Other, non DAI copier widgets could have the same  stream name (sname) as
the ALH copier and in that case the copier->data is NULL, no alh_data is
attached, which could lead to NULL pointer dereference.
We could check for this NULL pointer in sof_ipc4_prepare_copier_module()
and avoid the crash, but a similar loop in sof_ipc4_widget_setup_comp_dai()
will miscalculate the ALH device count, causing broken audio.

The correct fix is to harden the matching logic by making sure that the
1. widget is a DAI widget - so dai = w->private is valid
2. the dai (and thus the copier) is ALH copier

[ Backport to 6.6.y: Apply both widget-kind and ALH-type predicates to
  the target loops; the newer node_type local is absent and unused by
  this implementation. ]

Fixes: a150345aa758 ("ASoC: SOF: ipc4-topology: add SoundWire/ALH aggregation support")
Reported-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>
Link: https://github.com/thesofproject/sof/pull/9652
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Liam Girdwood <liam.r.girdwood@intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://patch.msgid.link/20250206084642.14988-1-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Assisted-by: LLM
Signed-off-by: Artem Dinaburg <artem@trailofbits.com>
---
This is patch 2 of 2 in the ordered 6.6.y backport series.
This change addresses CVE-2025-21870. Limits ALH aggregation searches to
DAI widgets of ALH type, preventing NULL private-data dereferences and
incorrect device counts from same-name non-DAI widgets.
Each loop checks WIDGET_IS_DAI() before interpreting w->private as a
DAI, then checks SOF_DAI_INTEL_ALH before incrementing the device
count or accessing copier data.

The fix is already present in 6.12.y, 6.18.y, and 7.2.y, but not in 6.6.y.
This fix also affects 6.1.y, which will need a separate backport; this
submission contains only the 6.6.y patch.

 sound/soc/sof/ipc4-topology.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/sound/soc/sof/ipc4-topology.c b/sound/soc/sof/ipc4-topology.c
index 18096aefce13..8911c075251c 100644
--- a/sound/soc/sof/ipc4-topology.c
+++ b/sound/soc/sof/ipc4-topology.c
@@ -577,10 +577,16 @@ static int sof_ipc4_widget_setup_comp_dai(struct snd_sof_widget *swidget)
 		}
 
 		list_for_each_entry(w, &sdev->widget_list, list) {
-			if (w->widget->sname &&
+			struct snd_sof_dai *alh_dai;
+
+			if (!WIDGET_IS_DAI(w->id) || !w->widget->sname ||
 			    strcmp(w->widget->sname, swidget->widget->sname))
 				continue;
 
+			alh_dai = w->private;
+			if (alh_dai->type != SOF_DAI_INTEL_ALH)
+				continue;
+
 			blob->alh_cfg.device_count++;
 		}
 
@@ -1692,11 +1698,13 @@ sof_ipc4_prepare_copier_module(struct snd_sof_widget *swidget,
 			 */
 			i = 0;
 			list_for_each_entry(w, &sdev->widget_list, list) {
-				if (w->widget->sname &&
+				if (!WIDGET_IS_DAI(w->id) || !w->widget->sname ||
 				    strcmp(w->widget->sname, swidget->widget->sname))
 					continue;
 
 				dai = w->private;
+				if (dai->type != SOF_DAI_INTEL_ALH)
+					continue;
 				alh_copier = (struct sof_ipc4_copier *)dai->private;
 				alh_data = &alh_copier->data;
 				blob->alh_cfg.mapping[i].device = alh_data->gtw_cfg.node_id;
-- 
2.39.5