From ad45babf7886e7a212ee1d5eda9ef49f696db43c Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Wed, 1 Dec 2021 08:36:05 +0100 Subject: [PATCH] ALSA: pcm: oss: Limit the period size to 16MB commit 8839c8c0f77ab8fc0463f4ab8b37fca3f70677c2 upstream. Set the practical limit to the period size (the fragment shift in OSS) instead of a full 31bit; a too large value could lead to the exhaust of memory as we allocate temporary buffers of the period size, too. As of this patch, we set to 16MB limit, which should cover all use cases. Reported-by: syzbot+bb348e9f9a954d42746f@syzkaller.appspotmail.com Reported-by: Bixuan Cui Cc: Link: https://lore.kernel.org/r/1638270978-42412-1-git-send-email-cuibixuan@linux.alibaba.com Link: https://lore.kernel.org/r/20211201073606.11660-3-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/oss/pcm_oss.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c index a99b187e6cc9..fce95b1dcc02 100644 --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -1953,7 +1953,7 @@ static int snd_pcm_oss_set_fragment1(struct snd_pcm_substream *substream, unsign if (runtime->oss.subdivision || runtime->oss.fragshift) return -EINVAL; fragshift = val & 0xffff; - if (fragshift >= 31) + if (fragshift >= 25) /* should be large enough */ return -EINVAL; runtime->oss.fragshift = fragshift; runtime->oss.maxfrags = (val >> 16) & 0xffff; -- 2.25.1