[PATCH] ASoC: wm_adsp: Prevent negative string length in wm_adsp_control_add()

[PATCH] ASoC: wm_adsp: Prevent negative string length in wm_adsp_control_add()

[Richard Fitzgerald]

Check that avail does not become < 1 in wm_adsp_control_add(). This
prevents overflows during subsequent operations.

The main aim is to trap a negative value in avail, but a zero length
would mean that the control ends up without a name, so 1 is the smallest
valid value.

Fixes: b7ede5af62ab6 ("ASoC: wm_adsp: Take prefix into account in control name length")
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
---
 sound/soc/codecs/wm_adsp.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/sound/soc/codecs/wm_adsp.c b/sound/soc/codecs/wm_adsp.c
index b8f3035af3ba1..7740a9c8ced32 100644
--- a/sound/soc/codecs/wm_adsp.c
+++ b/sound/soc/codecs/wm_adsp.c
@@ -46,6 +46,9 @@
 #define adsp_dbg(_dsp, fmt, ...) \
 	dev_dbg(_dsp->cs_dsp.dev, "%s: " fmt, _dsp->cs_dsp.name, ##__VA_ARGS__)
 
+#define adsp_warn_once(_dsp, fmt, ...) \
+	dev_warn_once(_dsp->cs_dsp.dev, "%s: " fmt, _dsp->cs_dsp.name, ##__VA_ARGS__)
+
 #define compr_err(_obj, fmt, ...) \
 	adsp_err(_obj->dsp, "%s: " fmt, _obj->name ? _obj->name : "legacy", \
 		 ##__VA_ARGS__)
@@ -625,6 +628,13 @@ int wm_adsp_control_add(struct cs_dsp_coeff_ctl *cs_ctl)
 		if (dsp->component->name_prefix)
 			avail -= strlen(dsp->component->name_prefix) + 1;
 
+		if (avail < 1) {
+			adsp_warn_once(dsp,
+				       "%.*s: ALSA prefix too long: control not created\n",
+				       cs_ctl->subname_len, cs_ctl->subname);
+			return -EINVAL;
+		}
+
 		/* Truncate the subname from the start if it is too long */
 		if (cs_ctl->subname_len > avail)
 			skip = cs_ctl->subname_len - avail;
-- 
2.47.3

Re: [PATCH] ASoC: wm_adsp: Prevent negative string length in wm_adsp_control_add()

[Mark Brown]

On Wed, 04 Nov 2026 13:33:22 +0000, Richard Fitzgerald wrote:
> ASoC: wm_adsp: Prevent negative string length in wm_adsp_control_add()

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-7.4

Thanks!

[1/1] ASoC: wm_adsp: Prevent negative string length in wm_adsp_control_add()
      https://git.kernel.org/broonie/sound/c/4d07af76ca41

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark