From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754831AbYHOKzZ (ORCPT ); Fri, 15 Aug 2008 06:55:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752852AbYHOKzN (ORCPT ); Fri, 15 Aug 2008 06:55:13 -0400 Received: from s200aog17.obsmtp.com ([207.126.144.131]:57503 "EHLO s200aog17.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752662AbYHOKzL (ORCPT ); Fri, 15 Aug 2008 06:55:11 -0400 X-Greylist: delayed 1237 seconds by postgrey-1.27 at vger.kernel.org; Fri, 15 Aug 2008 06:55:11 EDT Message-Id: <200808151034.CKM57557@mail1.bri.st.com> To: perex@perex.cz Cc: linux-kernel@vger.kernel.org, trivial@kernel.org From: Daniel THOMPSON Date: Fri, 15 Aug 2008 10:53:38 +0100 Subject: [PATCH] sound: Fix esoteric double free in the dummy sound driver. Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The dummy driver uses runtime->private_free but still frees its pcm structures on error paths. This is esoteric because the error paths in question are unreachable. Thus the bug is only a problem when someone copies this code into other drivers. Signed-off-by: Daniel R Thompson --- sound/drivers/dummy.c | 10 ++++------ 1 files changed, 4 insertions(+), 6 deletions(-) diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.c index 4e4c69e..90fc1ce 100644 --- a/sound/drivers/dummy.c +++ b/sound/drivers/dummy.c @@ -354,6 +354,7 @@ static int snd_card_dummy_playback_open(struct snd_pcm_substream *substream) if ((dpcm = new_pcm_stream(substream)) == NULL) return -ENOMEM; runtime->private_data = dpcm; + /* makes the infrastructure responsible for freeing dpcm */ runtime->private_free = snd_card_dummy_runtime_free; runtime->hw = snd_card_dummy_playback; if (substream->pcm->device & 1) { @@ -362,10 +363,8 @@ static int snd_card_dummy_playback_open(struct snd_pcm_substream *substream) } if (substream->pcm->device & 2) runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP|SNDRV_PCM_INFO_MMAP_VALID); - if ((err = add_playback_constraints(runtime)) < 0) { - kfree(dpcm); + if ((err = add_playback_constraints(runtime)) < 0) return err; - } return 0; } @@ -379,6 +378,7 @@ static int snd_card_dummy_capture_open(struct snd_pcm_substream *substream) if ((dpcm = new_pcm_stream(substream)) == NULL) return -ENOMEM; runtime->private_data = dpcm; + /* makes the infrastructure responsible for freeing dpcm */ runtime->private_free = snd_card_dummy_runtime_free; runtime->hw = snd_card_dummy_capture; if (substream->pcm->device == 1) { @@ -387,10 +387,8 @@ static int snd_card_dummy_capture_open(struct snd_pcm_substream *substream) } if (substream->pcm->device & 2) runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP|SNDRV_PCM_INFO_MMAP_VALID); - if ((err = add_capture_constraints(runtime)) < 0) { - kfree(dpcm); + if ((err = add_capture_constraints(runtime)) < 0) return err; - } return 0; } -- 1.5.5.1