[PATCH v2] ALSA: es18xx: check control allocation before private data setup

[Ruoyu Wang]

snd_es18xx_mixer() creates controls with snd_ctl_new1() and then stores
bookkeeping pointers or sets private_free before calling snd_ctl_add().
snd_ctl_new1() can return NULL on allocation failure, so those writes
can dereference a NULL control pointer.

Check the returned control pointers before using them and return -ENOMEM
on allocation failure.

Signed-off-by: Ruoyu Wang <ruoyuw560@xxxxxxxxx>
---
v2:
- Rebase on sound.git for-next.
- Resend only es18xx; the other v1 patches are already in for-next.

 sound/isa/es18xx.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/isa/es18xx.c b/sound/isa/es18xx.c
index df88d91e0fb..1a02da1679d 100644
--- a/sound/isa/es18xx.c
+++ b/sound/isa/es18xx.c
@@ -1762,6 +1762,8 @@ static int snd_es18xx_mixer(struct snd_card *card)
 	for (idx = 0; idx < ARRAY_SIZE(snd_es18xx_base_controls); idx++) {
 		struct snd_kcontrol *kctl;
 		kctl = snd_ctl_new1(&snd_es18xx_base_controls[idx], chip);
+		if (!kctl)
+			return -ENOMEM;
 		if (chip->caps & ES18XX_HWV) {
 			switch (idx) {
 			case 0:
@@ -1823,6 +1825,8 @@ static int snd_es18xx_mixer(struct snd_card *card)
 		for (idx = 0; idx < ARRAY_SIZE(snd_es18xx_hw_volume_controls); idx++) {
 			struct snd_kcontrol *kctl;
 			kctl = snd_ctl_new1(&snd_es18xx_hw_volume_controls[idx], chip);
+			if (!kctl)
+				return -ENOMEM;
 			if (idx == 0)
 				chip->hw_volume = kctl;
 			else
-- 
2.51.0