ALSA: pcm: disallow linking stream to itself

commit 951e273 upstream. Prevent SNDRV_PCM_IOCTL_LINK linking stream to itself - the code can't handle it. Fixed commit is not where bug was introduced, but changes the context significantly. Cc: [email protected] Fixes: 0888c32 ("pcm_native: switch to fdget()/fdput()") Signed-off-by: Michał Mirosław <[email protected]> Link: https://lore.kernel.org/r/89c4a2487609a0ed6af3ecf01cc972bdc59a7a2d.1591634956.git.mirq-linux@rere.qmqm.pl Signed-off-by: Takashi Iwai <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
repojohnray · Jun 17, 2020 · c8b0322 · c8b0322
1 parent 3e91083
commit c8b0322
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
@@ -2163,6 +2163,12 @@ static int snd_pcm_link(struct snd_pcm_substream *substream, int fd)
 	}
 	pcm_file = f.file->private_data;
 	substream1 = pcm_file->substream;
+
+	if (substream == substream1) {
+		res = -EINVAL;
+		goto _badf;
+	}
+
 	group = kzalloc(sizeof(*group), GFP_KERNEL);
 	if (!group) {
 		res = -ENOMEM;