ALSA: seq: Fix snd_seq_call_port_info_ioctl in compat mode

This reverts one hunk of
commit ef44a1ec6eee ("ALSA: sound/core: use memdup_user()"), which
replaced a number of kmalloc followed by memcpy with memdup calls.

In this case, we are copying from a struct snd_seq_port_info32 to a
struct snd_seq_port_info, but the latter is 4 bytes longer than the
32-bit version, so we need to separate kmalloc and copy calls.

Fixes: ef44a1ec6eee ('ALSA: sound/core: use memdup_user()')
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 5 insertions, 4 deletions

diff --git a/sound/core/seq/seq_compat.c b/sound/core/seq/seq_compat.c
index 81f7c109dc46..65175902a68a 100644
--- a/sound/core/seq/seq_compat.c
+++ b/sound/core/seq/seq_compat.c
@@ -49,11 +49,12 @@ static int snd_seq_call_port_info_ioctl(struct snd_seq_client *client, unsigned
         struct snd_seq_port_info *data;
         mm_segment_t fs;
 
-        data = memdup_user(data32, sizeof(*data32));
-        if (IS_ERR(data))
-                return PTR_ERR(data);
+        data = kmalloc(sizeof(*data), GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
 
-        if (get_user(data->flags, &data32->flags) ||
+        if (copy_from_user(data, data32, sizeof(*data32)) ||
+            get_user(data->flags, &data32->flags) ||
             get_user(data->time_queue, &data32->time_queue))
                 goto error;
         data->kernel = NULL;