[PATCH 6.1.y] ASoC: SOF: ipc3-control: Fix heap overflow in bytes_ext put/get

[Sasha Levin <sashal@kernel.org>]

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

[ Upstream commit fd46668d538993218eea19c6925c868ac0f2630c ]

The ipc_control_data buffer is allocated as kzalloc(max_size), where
max_size covers the entire struct sof_ipc_ctrl_data including its
flexible array payload. However, the bounds checks in bytes_ext_put
and _bytes_ext_get compared user data lengths against max_size
directly, ignoring that cdata->data sits at an offset of
sizeof(struct sof_ipc_ctrl_data) bytes into the allocation.

This allowed writing up to sizeof(struct sof_ipc_ctrl_data) bytes past
the end of the heap buffer from unprivileged userspace via the ALSA TLV
kcontrol interface, and similarly allowed over-reading adjacent heap
data on the get path.

Fix all bounds checks to subtract sizeof(*cdata) from max_size so they
reflect the actual space available at the cdata->data offset. Also fix
the error-path restore in bytes_ext_put which wrote to cdata->data
instead of cdata, causing the same overflow.

Fixes: 67ec2a091630 ("ASoC: SOF: Add bytes_ext control IPC ops for IPC3")
Cc: stable@vger.kernel.org
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Liam Girdwood <liam.r.girdwood@intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://patch.msgid.link/20260609083458.31193-7-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
[ replicated the single shared-helper bounds-check fix into the two standalone get functions and dropped the err_restore memcpy hunk absent in 6.1 ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/soc/sof/ipc3-control.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/sound/soc/sof/ipc3-control.c b/sound/soc/sof/ipc3-control.c
index 3fdc0d854e65d1..f204f91bcbc273 100644
--- a/sound/soc/sof/ipc3-control.c
+++ b/sound/soc/sof/ipc3-control.c
@@ -354,10 +354,13 @@ static int sof_ipc3_bytes_ext_get(struct snd_sof_control *scontrol,
 	cdata->data->abi = SOF_ABI_VERSION;
 
 	/* check data size doesn't exceed max coming from topology */
-	if (cdata->data->size > scontrol->max_size - sizeof(struct sof_abi_hdr)) {
-		dev_err_ratelimited(scomp->dev, "User data size %d exceeds max size %zu\n",
+	if (cdata->data->size > scontrol->max_size - sizeof(*cdata) -
+				sizeof(struct sof_abi_hdr)) {
+		dev_err_ratelimited(scomp->dev,
+				    "User data size %u exceeds max size %zu\n",
 				    cdata->data->size,
-				    scontrol->max_size - sizeof(struct sof_abi_hdr));
+				    scontrol->max_size - sizeof(*cdata) -
+				    sizeof(struct sof_abi_hdr));
 		return -EINVAL;
 	}
 
@@ -403,9 +406,17 @@ static int sof_ipc3_bytes_ext_put(struct snd_sof_control *scontrol,
 	}
 
 	/* be->max is coming from topology */
-	if (header.length > scontrol->max_size) {
-		dev_err_ratelimited(scomp->dev, "Bytes data size %d exceeds max %zu\n",
-				    header.length, scontrol->max_size);
+	if (header.length > scontrol->max_size - sizeof(*cdata)) {
+		dev_err_ratelimited(scomp->dev, "Bytes data size %u exceeds max %zu\n",
+				    header.length, scontrol->max_size - sizeof(*cdata));
+		return -EINVAL;
+	}
+
+	/* Ensure the data is large enough to contain the ABI header */
+	if (header.length < sizeof(struct sof_abi_hdr)) {
+		dev_err_ratelimited(scomp->dev,
+				    "Bytes data size %u less than ABI header %zu\n",
+				    header.length, sizeof(struct sof_abi_hdr));
 		return -EINVAL;
 	}
 
@@ -431,7 +442,7 @@ static int sof_ipc3_bytes_ext_put(struct snd_sof_control *scontrol,
 	}
 
 	/* be->max has been verified to be >= sizeof(struct sof_abi_hdr) */
-	if (cdata->data->size > scontrol->max_size - sizeof(struct sof_abi_hdr)) {
+	if (cdata->data->size > scontrol->max_size - sizeof(*cdata) - sizeof(struct sof_abi_hdr)) {
 		dev_err_ratelimited(scomp->dev, "Mismatch in ABI data size (truncated?)\n");
 		return -EINVAL;
 	}
@@ -473,10 +484,13 @@ static int sof_ipc3_bytes_ext_volatile_get(struct snd_sof_control *scontrol,
 		return ret;
 
 	/* check data size doesn't exceed max coming from topology */
-	if (cdata->data->size > scontrol->max_size - sizeof(struct sof_abi_hdr)) {
-		dev_err_ratelimited(scomp->dev, "User data size %d exceeds max size %zu\n",
+	if (cdata->data->size > scontrol->max_size - sizeof(*cdata) -
+				sizeof(struct sof_abi_hdr)) {
+		dev_err_ratelimited(scomp->dev,
+				    "User data size %u exceeds max size %zu\n",
 				    cdata->data->size,
-				    scontrol->max_size - sizeof(struct sof_abi_hdr));
+				    scontrol->max_size - sizeof(*cdata) -
+				    sizeof(struct sof_abi_hdr));
 		return -EINVAL;
 	}
 
-- 
2.53.0