Commit aa73aec6 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Takashi Iwai

ALSA: rawmidi: fix oops (use after free) when unloading a driver module

When a driver module is unloaded and the last still open file is a raw
MIDI device, the card and its devices will be actually freed in the
snd_card_file_remove() call when that file is closed.  Afterwards, rmidi
and rmidi->card point into freed memory, so the module pointer is likely
to be garbage.
(This was introduced by commit 9a1b64ca.)
Signed-off-by: default avatarClemens Ladisch <clemens@ladisch.de>
Reported-by: default avatarKrzysztof Foltman <wdev@foltman.com>
Cc: 2.6.30-2.6.35 <stable@kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent cd07202c
...@@ -535,13 +535,15 @@ static int snd_rawmidi_release(struct inode *inode, struct file *file) ...@@ -535,13 +535,15 @@ static int snd_rawmidi_release(struct inode *inode, struct file *file)
{ {
struct snd_rawmidi_file *rfile; struct snd_rawmidi_file *rfile;
struct snd_rawmidi *rmidi; struct snd_rawmidi *rmidi;
struct module *module;
rfile = file->private_data; rfile = file->private_data;
rmidi = rfile->rmidi; rmidi = rfile->rmidi;
rawmidi_release_priv(rfile); rawmidi_release_priv(rfile);
kfree(rfile); kfree(rfile);
module = rmidi->card->module;
snd_card_file_remove(rmidi->card, file); snd_card_file_remove(rmidi->card, file);
module_put(rmidi->card->module); module_put(module);
return 0; return 0;
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment