On Mon, Aug 19, 2019 at 06:25:43PM +0300, Jarkko Sakkinen wrote:
> The validation of TCS permissions was missing from
> sgx_validate_secinfo(). This patch adds the validation.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> ---
> arch/x86/kernel/cpu/sgx/driver/ioctl.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/sgx/driver/ioctl.c b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
> index 99b1b9776c3a..2415dcb20a6e 100644
> --- a/arch/x86/kernel/cpu/sgx/driver/ioctl.c
> +++ b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
> @@ -423,6 +423,12 @@ static int sgx_validate_secinfo(struct sgx_secinfo *secinfo)
> if ((perm & SGX_SECINFO_W) && !(perm & SGX_SECINFO_R))
> return -EINVAL;
>
> + /* CPU will silently overwrite the permissions as zero, which means
Comment style again. I looked it up just to double check :)
Documentation/process/coding-style.rst says:
When commenting the kernel API functions, please use the kernel-doc format.
See the files at :ref:`Documentation/doc-guide/ <doc_guide>` and
``scripts/kernel-doc`` for details.
The preferred style for long (multi-line) comments is:
.. code-block:: c
/*
* This is the preferred style for multi-line
* comments in the Linux kernel source code.
* Please use it consistently.
*
* Description: A column of asterisks on the left side,
* with beginning and ending almost-blank lines.
*/
For files in net/ and drivers/net/ the preferred style for long (multi-line)
comments is a little different.
.. code-block:: c
/* The preferred comment style for files in net/ and drivers/net
* looks like this.
*
* It is nearly the same as the generally preferred comment style,
* but there is no initial almost-blank line.
*/
> + * that we need to validate it ourselves.
> + */
> + if (page_type == SGX_SECINFO_TCS && perm)
> + return -EINVAL;
Why are we validating the TCS protection bits? Hardware ignores them, so
why do we care? sgx_ioc_enclave_add_page() sets the internal protection
bits so there's no danger of putting the wrong thing in the page tables.
> +
> if (secinfo->flags & SGX_SECINFO_RESERVED_MASK)
> return -EINVAL;
>
> --
> 2.20.1
>
