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Commit a86bde89 authored by Xiaomeng Tong's avatar Xiaomeng Tong Committed by Greg Kroah-Hartman
Browse files

ALSA: cs4236: fix an incorrect NULL check on list iterator 



commit 0112f822f8a6d8039c94e0bc9b264d7ffc5d4704 upstream.

The bug is here:
	err = snd_card_cs423x_pnp(dev, card->private_data, pdev, cdev);

The list iterator value 'cdev' will *always* be set and non-NULL
by list_for_each_entry(), so it is incorrect to assume that the
iterator value will be NULL if the list is empty or no element
is found.

To fix the bug, use a new variable 'iter' as the list iterator,
while use the original variable 'cdev' as a dedicated pointer
to point to the found element. And snd_card_cs423x_pnp() itself
has NULL check for cdev.

Cc: stable@vger.kernel.org
Fixes: c2b73d14 ("ALSA: cs4236: cs4232 and cs4236 driver merge to solve PnP BIOS detection")
Signed-off-by: default avatarXiaomeng Tong <xiam0nd.tong@gmail.com>
Link: https://lore.kernel.org/r/20220327060822.4735-1-xiam0nd.tong@gmail.com


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 84897741

sound/isa/cs423x/cs4236.c

+5 −3
Original line number Diff line number Diff line
@@ -544,7 +544,7 @@ static int snd_cs423x_pnpbios_detect(struct pnp_dev *pdev, 
	static int dev;

	int err;

	struct snd_card *card;

	struct pnp_dev *cdev;

	struct pnp_dev *cdev, *iter;

	char cid[PNP_ID_LEN];



	if (pnp_device_is_isapnp(pdev))
@@ -560,10 +560,12 @@ static int snd_cs423x_pnpbios_detect(struct pnp_dev *pdev, 
	strcpy(cid, pdev->id[0].id);

	cid[5] = '1';

	cdev = NULL;

	list_for_each_entry(cdev, &(pdev->protocol->devices), protocol_list) {

		if (!strcmp(cdev->id[0].id, cid))

	list_for_each_entry(iter, &(pdev->protocol->devices), protocol_list) {

		if (!strcmp(iter->id[0].id, cid)) {

			cdev = iter;

			break;

		}

	}

	err = snd_cs423x_card_new(&pdev->dev, dev, &card);

	if (err < 0)

		return err;