linux-kernel - Re: [GIT PULL] TPM driver robustness fixes

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Date:	Mon, 28 Mar 2011 13:06:58 -0300
From:	Rajiv Andrade <srajiv@...ux.vnet.ibm.com>
To:	Peter Huewe <huewe.external.infineon@...glemail.com>
CC:	James Morris <jmorris@...ei.org>,
	Linux kernel mailing list <linux-kernel@...r.kernel.org>
Subject: Re: [GIT PULL] TPM driver robustness fixes

On 03/22/2011 01:08 PM, Peter Huewe wrote:
> Or rather:
> diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
> index d184d75..2f2f65e 100644
> --- a/drivers/char/tpm/tpm.c
> +++ b/drivers/char/tpm/tpm.c
> @@ -1052,6 +1052,7 @@ ssize_t tpm_read(struct file *file, char __user *buf,
>  {
>         struct tpm_chip *chip = file->private_data;
>         ssize_t ret_size;
> +       int rc;
> 
>         del_singleshot_timer_sync(&chip->user_read_timer);
>         flush_work_sync(&chip->work);
> @@ -1062,8 +1063,11 @@ ssize_t tpm_read(struct file *file, char __user *buf,
>                         ret_size = size;
> 
>                 mutex_lock(&chip->buffer_mutex);
> -               if (copy_to_user(buf, chip->data_buffer, ret_size))
> +               rc = copy_to_user(buf, chip->data_buffer, ret_size);
> +               memset(chip->data_buffer, 0, ret_size);
> +               if (rc)
>                         ret_size = -EFAULT;
> +
>                 mutex_unlock(&chip->buffer_mutex);
>         }
> 
> 
> 
> Thanks,
> Peter

This approach is definitely the best.

Thanks,
Rajiv


-- 
Thanks,
Rajiv Andrade <srajiv@...ibm.com>
Security Development
IBM Linux Technology Center
+55 19 81095527

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