[alsa-devel] [patch] ALSA: echoaudio: use after free on error

[walter harms]

Am 05.03.2014 12:07, schrieb Dan Carpenter:
> There are some places where we dereference "chip" in the error message
> but we've already freed it.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
> 
> diff --git a/sound/pci/echoaudio/echoaudio.c b/sound/pci/echoaudio/echoaudio.c
> index 166ec0c120d4..9f10c9e0df5e 100644
> --- a/sound/pci/echoaudio/echoaudio.c
> +++ b/sound/pci/echoaudio/echoaudio.c
> @@ -1990,8 +1990,8 @@ static int snd_echo_create(struct snd_card *card,
>  
>  	if ((chip->iores = request_mem_region(chip->dsp_registers_phys, sz,
>  					      ECHOCARD_NAME)) == NULL) {


this should read:
chip->iores = request_mem_region(chip->dsp_registers_phys, sz,ECHOCARD_NAME);
if (chip->iores == NULL) {

re,
 wh

> -		snd_echo_free(chip);
>  		dev_err(chip->card->dev, "cannot get memory region\n");
> +		snd_echo_free(chip);
>  		return -EBUSY;
>  	}
>  	chip->dsp_registers = (volatile u32 __iomem *)
> @@ -1999,8 +1999,8 @@ static int snd_echo_create(struct snd_card *card,
>  
>  	if (request_irq(pci->irq, snd_echo_interrupt, IRQF_SHARED,
>  			KBUILD_MODNAME, chip)) {
> -		snd_echo_free(chip);
>  		dev_err(chip->card->dev, "cannot grab irq\n");
> +		snd_echo_free(chip);
>  		return -EBUSY;
>  	}
>  	chip->irq = pci->irq;
> @@ -2012,8 +2012,8 @@ static int snd_echo_create(struct snd_card *card,
>  	if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, snd_dma_pci_data(chip->pci),
>  				sizeof(struct comm_page),
>  				&chip->commpage_dma_buf) < 0) {
> -		snd_echo_free(chip);
>  		dev_err(chip->card->dev, "cannot allocate the comm page\n");
> +		snd_echo_free(chip);
>  		return -ENOMEM;
>  	}
>  	chip->comm_page_phys = chip->commpage_dma_buf.addr;
> @@ -2291,8 +2291,8 @@ static int snd_echo_resume(struct device *dev)
>  
>  	if (request_irq(pci->irq, snd_echo_interrupt, IRQF_SHARED,
>  			KBUILD_MODNAME, chip)) {
> -		snd_echo_free(chip);
>  		dev_err(chip->card->dev, "cannot grab irq\n");
> +		snd_echo_free(chip);
>  		return -EBUSY;
>  	}
>  	chip->irq = pci->irq;
> --
> To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
> the body of a message to majordomo at vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>