Eric Lee / smarc-fsl-linux-kernel

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Commit aa73aec6c385e2c797ac25cc7ccf0318031de7c8

Authored by Clemens Ladisch
Committed by Takashi Iwai
1 parent cd07202cc8

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 9a1b64caac82aa02cb74587ffc798e6f42c6170a.)

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Reported-by: Krzysztof Foltman <wdev@foltman.com>
Cc: 2.6.30-2.6.35 <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Showing 1 changed file with 3 additions and 1 deletions Side-by-side Diff

sound/core/rawmidi.c
Diff comments   View file @ aa73aec
... ... @@ -535,13 +535,15 @@
535 535 {
536 536 struct snd_rawmidi_file *rfile;
537 537 struct snd_rawmidi *rmidi;
  538 + struct module *module;
538 539  
539 540 rfile = file->private_data;
540 541 rmidi = rfile->rmidi;
541 542 rawmidi_release_priv(rfile);
542 543 kfree(rfile);
  544 + module = rmidi->card->module;
543 545 snd_card_file_remove(rmidi->card, file);
544   - module_put(rmidi->card->module);
  546 + module_put(module);
545 547 return 0;
546 548 }
547 549