Re: [PATCH v30 10/20] x86/sgx: Linux Enclave Driver

On Thu, May 21, 2020 at 12:12:36PM -0700, Sean Christopherson wrote:

On Fri, May 15, 2020 at 03:44:00AM +0300, Jarkko Sakkinen wrote:

quoted

+long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
+{
+	struct sgx_encl *encl = filep->private_data;
+	int ret, encl_flags;
+
+	encl_flags = atomic_fetch_or(SGX_ENCL_IOCTL, &encl->flags);
+	if (encl_flags & SGX_ENCL_IOCTL)
+		return -EBUSY;
+
+	if (encl_flags & SGX_ENCL_DEAD)
+		return -EFAULT;

Returning immediately is wrong as it leaves SGX_ENCL_IOCTL set.  This results
in the application seeing -EBUSY on future ioctls() instead of -EFAULT.  Can be
fixed as below.  Do you want me to send a formal patch on linux-sgx?

I just rewrote the same thing.

/Jarkko