ASoC: SOF: ipc3-control: Fix heap overflow in bytes_ext put/get

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>

diff --git a/sound/soc/sof/ipc3-control.c b/sound/soc/sof/ipc3-control.c
index 1f5538bbc50f054ef8e0c2a53b59d30ab69580b6..d1697401b1da0d46dfbf980ce1b9f0fcbb9c893a 100644 (file)
--- a/sound/soc/sof/ipc3-control.c
+++ b/sound/soc/sof/ipc3-control.c
@@ -398,9 +398,17 @@ 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;
        }
 
@@ -436,7 +444,7 @@ 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");
                goto err_restore;
        }
@@ -452,7 +460,7 @@ static int sof_ipc3_bytes_ext_put(struct snd_sof_control *scontrol,
 err_restore:
        /* If we have an issue, we restore the old, valid bytes control data */
        if (scontrol->old_ipc_control_data) {
-               memcpy(cdata->data, scontrol->old_ipc_control_data, scontrol->max_size);
+               memcpy(cdata, scontrol->old_ipc_control_data, scontrol->max_size);
                kfree(scontrol->old_ipc_control_data);
                scontrol->old_ipc_control_data = NULL;
        }
@@ -491,10 +499,13 @@ static int _sof_ipc3_bytes_ext_get(struct snd_sof_control *scontrol,
        }
 
        /* 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;
        }