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: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx> --- drivers/firmware/cirrus/cs_dsp.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/firmware/cirrus/cs_dsp.c b/drivers/firmware/cirrus/cs_dsp.c index 16484ab9b09d..be8747d227db 100644 --- a/drivers/firmware/cirrus/cs_dsp.c +++ b/drivers/firmware/cirrus/cs_dsp.c @@ -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; -- 2.39.2
