lkml.org 
[lkml]   [2020]   [May]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH v30 10/20] x86/sgx: Linux Enclave Driver
On Fri, May 15, 2020 at 03:44:00AM +0300, Jarkko Sakkinen wrote:
> +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?

diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 77757a74644d..df35a79e915c 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -751,8 +751,10 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
if (encl_flags & SGX_ENCL_IOCTL)
return -EBUSY;

- if (encl_flags & SGX_ENCL_DEAD)
- return -EFAULT;
+ if (encl_flags & SGX_ENCL_DEAD) {
+ ret = -EFAULT;
+ goto out;
+ }

switch (cmd) {
case SGX_IOC_ENCLAVE_CREATE:
@@ -772,6 +774,7 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
break;
}

+out:
atomic_andnot(SGX_ENCL_IOCTL, &encl->flags);

return ret;

> +
> + switch (cmd) {
> + case SGX_IOC_ENCLAVE_CREATE:
> + ret = sgx_ioc_enclave_create(encl, (void __user *)arg);
> + break;
> + case SGX_IOC_ENCLAVE_ADD_PAGES:
> + ret = sgx_ioc_enclave_add_pages(encl, (void __user *)arg);
> + break;
> + case SGX_IOC_ENCLAVE_INIT:
> + ret = sgx_ioc_enclave_init(encl, (void __user *)arg);
> + break;
> + default:
> + ret = -ENOIOCTLCMD;
> + break;
> + }
> +
> + atomic_andnot(SGX_ENCL_IOCTL, &encl->flags);
> +
> + return ret;
> +}

\
 
 \ /
  Last update: 2020-05-21 21:13    [W:0.376 / U:2.352 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site