On Wed, Jun 19, 2019 at 03:23:54PM -0700, Sean Christopherson wrote:
> Do not allow an enclave page to be mapped with PROT_EXEC if the source
> vma does not have VM_MAYEXEC. This effectively enforces noexec as
> do_mmap() clears VM_MAYEXEC if the vma is being loaded from a noexec
> path, i.e. prevents executing a file by loading it into an enclave.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> ---
> arch/x86/kernel/cpu/sgx/driver/ioctl.c | 42 +++++++++++++++++++++++---
> 1 file changed, 37 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/sgx/driver/ioctl.c b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
> index e18d2afd2aad..1fca70a36ce3 100644
> --- a/arch/x86/kernel/cpu/sgx/driver/ioctl.c
> +++ b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
> @@ -564,6 +564,39 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long addr,
> return ret;
> }
>
> +static int sgx_encl_page_copy(void *dst, unsigned long src, unsigned long prot)
I will probably forget the context with this name after this has been
merged :-) So many functions dealing with enclave pages. Two
alternatives that come up to my mind:
1. sgx_encl_page_user_import()
2. sgx_encl_page_user_copy_from()
Not saying that they are beatiful names but at least you immediately
know the context.
> +{
> + struct vm_area_struct *vma;
> + int ret;
> +
> + /* Hold mmap_sem across copy_from_user() to avoid a TOCTOU race. */
> + down_read(¤t->mm->mmap_sem);
> +
> + /* Query vma's VM_MAYEXEC as an indirect path_noexec() check. */
> + if (prot & PROT_EXEC) {
> + vma = find_vma(current->mm, src);
> + if (!vma) {
> + ret = -EFAULT;
> + goto out;
Should this be -EINVAL instead?
/Jarkko
