Commit c58e3689 authored by Chengfeng Ye's avatar Chengfeng Ye Committed by Kaixiong Yu
Browse files

ALSA: gus: fix null pointer dereference on pointer block 

stable inclusion
from stable-v4.19.218
commit ab4c1ebc40f699f48346f634d7b72b9c5193f315
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9FNFE
CVE: CVE-2021-47207

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ab4c1ebc40f699f48346f634d7b72b9c5193f315



--------------------------------

[ Upstream commit a0d21bb3 ]

The pointer block return from snd_gf1_dma_next_block could be
null, so there is a potential null pointer dereference issue.
Fix this by adding a null check before dereference.

Signed-off-by: default avatarChengfeng Ye <cyeaa@connect.ust.hk>
Link: https://lore.kernel.org/r/20211024104611.9919-1-cyeaa@connect.ust.hk


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarKaixiong Yu <yukaixiong@huawei.com>
parent c9fdcc30

sound/isa/gus/gus_dma.c

+2 −0
Original line number Diff line number Diff line
@@ -141,6 +141,8 @@ static void snd_gf1_dma_interrupt(struct snd_gus_card * gus) 
	}

	block = snd_gf1_dma_next_block(gus);

	spin_unlock(&gus->dma_lock);

	if (!block)

		return;

	snd_gf1_dma_program(gus, block->addr, block->buf_addr, block->count, (unsigned short) block->cmd);

	kfree(block);

#if 0