From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754988Ab1ABHpr (ORCPT ); Sun, 2 Jan 2011 02:45:47 -0500 Received: from mail.windriver.com ([147.11.1.11]:36249 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754342Ab1ABHYT (ORCPT ); Sun, 2 Jan 2011 02:24:19 -0500 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Clemens Ladisch , Takashi Iwai , Paul Gortmaker Subject: [34-longterm 164/260] ALSA: rawmidi: fix oops (use after free) when unloading a driver module Date: Sun, 2 Jan 2011 02:17:40 -0500 Message-Id: <1293952756-15010-165-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.3.3 In-Reply-To: <1293952756-15010-1-git-send-email-paul.gortmaker@windriver.com> References: <1293952756-15010-1-git-send-email-paul.gortmaker@windriver.com> X-OriginalArrivalTime: 02 Jan 2011 07:23:10.0072 (UTC) FILETIME=[E8897F80:01CBAA4D] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Clemens Ladisch 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 Reported-by: Krzysztof Foltman Signed-off-by: Takashi Iwai Signed-off-by: Paul Gortmaker --- sound/core/rawmidi.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-) diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c index 0f5a194..5fac1a3 100644 --- a/sound/core/rawmidi.c +++ b/sound/core/rawmidi.c @@ -531,13 +531,15 @@ static int snd_rawmidi_release(struct inode *inode, struct file *file) { 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; } -- 1.7.3.3