From: Takashi Iwai <tiwai@suse.de>
To: alsa-devel@alsa-project.org
Subject: [alsa-devel] [PATCH] ALSA: pcm: oss: Avoid potential buffer overflows
Date: Wed, 4 Dec 2019 15:48:24 +0100 [thread overview]
Message-ID: <20191204144824.17801-1-tiwai@suse.de> (raw)
syzkaller reported an invalid access in PCM OSS read, and this seems
to be an overflow of the internal buffer allocated for a plugin.
Since the rate plugin adjusts its transfer size dynamically, the
calculation for the chained plugin might be bigger than the given
buffer size in some extreme cases, which lead to such an buffer
overflow as caught by KASAN.
Fix it by limiting the max transfer size properly by checking against
the destination size in each plugin transfer callback.
Reported-by: syzbot+f153bde47a62e0b05f83@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/core/oss/linear.c | 2 ++
sound/core/oss/mulaw.c | 2 ++
sound/core/oss/route.c | 2 ++
3 files changed, 6 insertions(+)
diff --git a/sound/core/oss/linear.c b/sound/core/oss/linear.c
index 2045697f449d..797d838a2f9e 100644
--- a/sound/core/oss/linear.c
+++ b/sound/core/oss/linear.c
@@ -107,6 +107,8 @@ static snd_pcm_sframes_t linear_transfer(struct snd_pcm_plugin *plugin,
}
}
#endif
+ if (frames > dst_channels[0].frames)
+ frames = dst_channels[0].frames;
convert(plugin, src_channels, dst_channels, frames);
return frames;
}
diff --git a/sound/core/oss/mulaw.c b/sound/core/oss/mulaw.c
index 7915564bd394..3788906421a7 100644
--- a/sound/core/oss/mulaw.c
+++ b/sound/core/oss/mulaw.c
@@ -269,6 +269,8 @@ static snd_pcm_sframes_t mulaw_transfer(struct snd_pcm_plugin *plugin,
}
}
#endif
+ if (frames > dst_channels[0].frames)
+ frames = dst_channels[0].frames;
data = (struct mulaw_priv *)plugin->extra_data;
data->func(plugin, src_channels, dst_channels, frames);
return frames;
diff --git a/sound/core/oss/route.c b/sound/core/oss/route.c
index c8171f5783c8..72dea04197ef 100644
--- a/sound/core/oss/route.c
+++ b/sound/core/oss/route.c
@@ -57,6 +57,8 @@ static snd_pcm_sframes_t route_transfer(struct snd_pcm_plugin *plugin,
return -ENXIO;
if (frames == 0)
return 0;
+ if (frames > dst_channels[0].frames)
+ frames = dst_channels[0].frames;
nsrcs = plugin->src_format.channels;
ndsts = plugin->dst_format.channels;
--
2.16.4
_______________________________________________
Alsa-devel mailing list
Alsa-devel@alsa-project.org
https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
reply other threads:[~2019-12-04 14:49 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191204144824.17801-1-tiwai@suse.de \
--to=tiwai@suse.de \
--cc=alsa-devel@alsa-project.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).