ALSA: seq: Fix snd_seq_call_port_info_ioctl in compat mode

commit 9586495dc3011a80602329094e746dbce16cb1f1 upstream.

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>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/sound/core/seq/seq_compat.c b/sound/core/seq/seq_compat.c
index 81f7c109dc46e1b8ef9b4a2a67477fdf72940ef6..65175902a68a841650ac818f8fde713eca60c5b5 100644 (file)
--- 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;