6.6-stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai tiwai@suse.de
[ Upstream commit 50ed081284fe2bfd1f25e8b92f4f6a4990e73c0a ]
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 same 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 adds the same input value validation for user control elements at its put callback. 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@molgen.mpg.de Closes: https://lore.kernel.org/r/1d44be36-9bb9-4d82-8953-5ae2a4f09405@molgen.mpg.de Reviewed-by: Jaroslav Kysela perex@perex.cz Reviewed-by: Mark Brown broonie@kernel.org Reviewed-by: Takashi Sakamoto o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai tiwai@suse.de Link: https://lore.kernel.org/20240616073454.16512-4-tiwai@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- sound/core/control.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/sound/core/control.c b/sound/core/control.c index 59c8658966d4..dd4bdb39782c 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -1553,12 +1553,16 @@ static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol, static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol) { - int change; + int err, change; struct user_element *ue = kcontrol->private_data; unsigned int size = ue->elem_data_size; char *dst = ue->elem_data + snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
+ err = sanity_check_input_values(ue->card, ucontrol, &ue->info, false); + if (err < 0) + return err; + change = memcmp(&ucontrol->value, dst, size) != 0; if (change) memcpy(dst, &ucontrol->value, size);