Re: [PATCH] ALSA: pci: Fix memory leak in snd_korg1212_create

From: Takashi Iwai <tiwai@suse.de>
To: Navid Emamdoost <navid.emamdoost@gmail.com>
Cc: emamd001@umn.edu, smccaman@umn.edu, kjlu@umn.edu,
	Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Richard Fontana <rfontana@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ALSA: pci: Fix memory leak in snd_korg1212_create
Date: Mon, 28 Oct 2019 07:31:35 +0100	[thread overview]
Message-ID: <s5hmudlmldk.wl-tiwai@suse.de> (raw)
In-Reply-To: <20191027191206.30820-1-navid.emamdoost@gmail.com>

On Sun, 27 Oct 2019 20:12:04 +0100,
Navid Emamdoost wrote:
> 
> In the implementation of snd_korg1212_create() the allocated memory for
> korg1212 is leaked in cases of error. Release korg1212 via
> snd_korg1212_free() if either of these calls fail:
> snd_korg1212_downloadDSPCode(), snd_pcm_new(), or snd_ctl_add().

This also leads to the double-free.  The code path is after
snd_device_new() which has its own destructor callback.

thanks,

Takashi

> 
> Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
> ---
>  sound/pci/korg1212/korg1212.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/pci/korg1212/korg1212.c b/sound/pci/korg1212/korg1212.c
> index 0d81eac0a478..e976e857d915 100644
> --- a/sound/pci/korg1212/korg1212.c
> +++ b/sound/pci/korg1212/korg1212.c
> @@ -2367,8 +2367,10 @@ static int snd_korg1212_create(struct snd_card *card, struct pci_dev *pci,
>  
>  	mdelay(CARD_BOOT_DELAY_IN_MS);
>  
> -        if (snd_korg1212_downloadDSPCode(korg1212))
> +	if (snd_korg1212_downloadDSPCode(korg1212)) {
> +		snd_korg1212_free(korg1212);
>          	return -EBUSY;
> +	}
>  
>          K1212_DEBUG_PRINTK("korg1212: dspMemPhy = %08x U[%08x], "
>                 "PlayDataPhy = %08x L[%08x]\n"
> @@ -2383,8 +2385,11 @@ static int snd_korg1212_create(struct snd_card *card, struct pci_dev *pci,
>                 korg1212->RoutingTablePhy, LowerWordSwap(korg1212->RoutingTablePhy),
>                 korg1212->AdatTimeCodePhy, LowerWordSwap(korg1212->AdatTimeCodePhy));
>  
> -        if ((err = snd_pcm_new(korg1212->card, "korg1212", 0, 1, 1, &korg1212->pcm)) < 0)
> +	err = snd_pcm_new(korg1212->card, "korg1212", 0, 1, 1, &korg1212->pcm);
> +	if (err < 0) {
> +		snd_korg1212_free(korg1212);
>                  return err;
> +	}
>  
>  	korg1212->pcm->private_data = korg1212;
>          korg1212->pcm->private_free = snd_korg1212_free_pcm;
> @@ -2398,8 +2403,10 @@ static int snd_korg1212_create(struct snd_card *card, struct pci_dev *pci,
>  
>          for (i = 0; i < ARRAY_SIZE(snd_korg1212_controls); i++) {
>                  err = snd_ctl_add(korg1212->card, snd_ctl_new1(&snd_korg1212_controls[i], korg1212));
> -                if (err < 0)
> +		if (err < 0) {
> +			snd_korg1212_free(korg1212);
>                          return err;
> +		}
>          }
>  
>          snd_korg1212_proc_init(korg1212);
> -- 
> 2.17.1
> 