On 14. 06. 24 14:47, Takashi Iwai wrote:
Although we have already a mechanism for sanity checks of input values for control writes, it's not applied unless the kconfig CONFIG_SND_CTL_INPUT_VALIDATION is set due to the performance reason. Nevertheless, it still makes sense to apply the check for user elements despite of its cost, as that's the only way to filter out the invalid values; the user controls are handled solely in ALSA core code, and there is no corresponding driver, after all. This patch enables the input value validation for user control elements no matter whether CONFIG_SND_CTL_INPUT_VALIDATION is set or not. The kselftest will be happier with this change, as the incorrect values will be bailed out now with errors. For other normal controls, the check is applied still only when CONFIG_SND_CTL_INPUT_VALIDATION is set. Reported-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx> Closes: https://lore.kernel.org/r/1d44be36-9bb9-4d82-8953-5ae2a4f09405@xxxxxxxxxxxxx Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> --- sound/core/control.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sound/core/control.c b/sound/core/control.c index fb0c60044f7b..50890983d7e2 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -1317,7 +1317,8 @@ static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file, snd_ctl_build_ioff(&control->id, kctl, index_offset); result = snd_power_ref_and_wait(card); /* validate input values */ - if (IS_ENABLED(CONFIG_SND_CTL_INPUT_VALIDATION) && !result) { + if ((IS_ENABLED(CONFIG_SND_CTL_INPUT_VALIDATION) || + (vd->access & SNDRV_CTL_ELEM_ACCESS_USER)) && !result) { struct snd_ctl_elem_info info;
The info structure for user elements may be used directly without this intermediate variable for the validation. But it may be a possible future improvement.
Jaroslav -- Jaroslav Kysela <perex@xxxxxxxx> Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
