Messages in this thread Patch in this message |  | | | Date | Fri, 22 Oct 2010 11:34:33 -0700 | | From | Greg KH <> | | Subject | [06/66] ALSA: rawmidi: fix oops (use after free) when unloading a driver module |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
------------------ From: Clemens Ladisch <clemens@ladisch.de>
commit aa73aec6c385e2c797ac25cc7ccf0318031de7c8 upstream.
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 9a1b64caac82aa02cb74587ffc798e6f42c6170a.)
Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Reported-by: Krzysztof Foltman <wdev@foltman.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- sound/core/rawmidi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/sound/core/rawmidi.c +++ b/sound/core/rawmidi.c @@ -530,13 +530,15 @@ static int snd_rawmidi_release(struct in { struct snd_rawmidi_file *rfile; struct snd_rawmidi *rmidi; + struct module *module; rfile = file->private_data; rmidi = rfile->rmidi; rawmidi_release_priv(rfile); kfree(rfile); + module = rmidi->card->module; snd_card_file_remove(rmidi->card, file); - module_put(rmidi->card->module); + module_put(module); return 0; }
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