From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 4 Jan 2018 15:39:27 +0000 (+0100)
Subject: ALSA: pcm: Add missing error checks in OSS emulation plugin builder
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=de98c69ff495ba992f6ddbbf097d3311ae92db34

ALSA: pcm: Add missing error checks in OSS emulation plugin builder

commit 6708913750344a900f2e73bfe4a4d6dbbce4fe8d upstream.

In the OSS emulation plugin builder where the frame size is parsed in
the plugin chain, some places miss the possible errors returned from
the plugin src_ or dst_frames callback.

This patch papers over such places.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/sound/core/oss/pcm_plugin.c b/sound/core/oss/pcm_plugin.c
index 71cc3ddf5c15..c6cecf7cb3fa 100644
--- a/sound/core/oss/pcm_plugin.c
+++ b/sound/core/oss/pcm_plugin.c
@@ -589,18 +589,26 @@ snd_pcm_sframes_t snd_pcm_plug_write_transfer(struct snd_pcm_substream *plug, st
 	snd_pcm_sframes_t frames = size;
 
 	plugin = snd_pcm_plug_first(plug);
-	while (plugin && frames > 0) {
+	while (plugin) {
+		if (frames <= 0)
+			return frames;
 		if ((next = plugin->next) != NULL) {
 			snd_pcm_sframes_t frames1 = frames;
-			if (plugin->dst_frames)
+			if (plugin->dst_frames) {
 				frames1 = plugin->dst_frames(plugin, frames);
+				if (frames1 <= 0)
+					return frames1;
+			}
 			if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
 				return err;
 			}
 			if (err != frames1) {
 				frames = err;
-				if (plugin->src_frames)
+				if (plugin->src_frames) {
 					frames = plugin->src_frames(plugin, frames1);
+					if (frames <= 0)
+						return frames;
+				}
 			}
 		} else
 			dst_channels = NULL;