From 02eca83e46be4448ff706f57ef272e2e9458dd65 Mon Sep 17 00:00:00 2001 From: Peter Ujfalusi Date: Tue, 12 May 2026 08:32:02 +0300 Subject: [PATCH] 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. Signed-off-by: Peter Ujfalusi --- sound/soc/sof/ipc3-control.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/sound/soc/sof/ipc3-control.c b/sound/soc/sof/ipc3-control.c index 2b1befad6d5c0d..58d04b67c22f88 100644 --- a/sound/soc/sof/ipc3-control.c +++ b/sound/soc/sof/ipc3-control.c @@ -389,9 +389,9 @@ static int sof_ipc3_bytes_ext_put(struct snd_sof_control *scontrol, } /* be->max is coming from topology */ - if (header.length > scontrol->max_size) { + if (header.length > scontrol->max_size - sizeof(*cdata)) { dev_err_ratelimited(scomp->dev, "Bytes data size %d exceeds max %zu\n", - header.length, scontrol->max_size); + header.length, scontrol->max_size - sizeof(*cdata)); return -EINVAL; } @@ -427,7 +427,7 @@ 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; } @@ -443,7 +443,7 @@ 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; } @@ -482,10 +482,13 @@ 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 %d 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; }