Unverified Commit 62412a93 authored by Richard Fitzgerald's avatar Richard Fitzgerald Committed by Mark Brown
Browse files

firmware: cs_dsp: Don't allow writes to read-only controls 



Add a check to cs_dsp_coeff_write_ctrl() to abort if the control
is not writeable.

The cs_dsp code originated as an ASoC driver (wm_adsp) where all
controls were exported as ALSA controls. It relied on ALSA to
enforce the read-only permission. Now that the code has been
separated from ALSA/ASoC it must perform its own permission check.

This isn't currently causing any problems so there shouldn't be any
need to backport this. If the client of cs_dsp exposes the control as
an ALSA control, it should set permissions on that ALSA control to
protect it. The few uses of cs_dsp_coeff_write_ctrl() inside drivers
are for writable controls.

Signed-off-by: default avatarRichard Fitzgerald <rf@opensource.cirrus.com>
Link: https://patch.msgid.link/20240702110809.16836-1-rf@opensource.cirrus.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent a893a804

drivers/firmware/cirrus/cs_dsp.c

+3 −0
Original line number Diff line number Diff line
@@ -796,6 +796,9 @@ int cs_dsp_coeff_write_ctrl(struct cs_dsp_coeff_ctl *ctl, 


	lockdep_assert_held(&ctl->dsp->pwr_lock);



	if (ctl->flags && !(ctl->flags & WMFW_CTL_FLAG_WRITEABLE))

		return -EPERM;



	if (len + off * sizeof(u32) > ctl->len)

		return -EINVAL;