On 5/19/23 11:37, Steffen Eiden wrote:
Userspace can call the List Secrets Ultravisor Call
using IOCTLs on the uvdevice.
During the handling of the new IOCTL nr the uvdevice will do some sanity
checks first. Then, perform the Ultravisor command, and copy the answer
to userspace.
If the List Secrets UV facility is not present, UV will return
invalid command rc. This won't be fenced in the driver and does not
result in a negative return value. This is also true for any other
possible error code the UV can return.
Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
---
[...]
+/** uvio_list_secrets() - perform a List Secret UVC
+ *
+ * @uv_ioctl: ioctl control block
+ *
+ * uvio_list_secrets() performs the List Secret Ultravisor Call.
+ * It verifies that the given userspace argument address is valid and its size
+ * is sane. Every other check is made by the Ultravisor (UV) and won't result
+ * in a negative return value. It builds the request, performs the UV-call,
+ * and copies the result to userspace.
+ *
+ * The argument specifies the location for the result of the UV-Call.
+ *
+ * If the List Secrets UV facility is not present,
+ * UV will return invalid command rc. This won't be fenced in the driver
+ * and does not result in a negative return value.
+ *
+ * Context: might sleep
+ *
+ * Return: 0 on success or a negative error code on error.
+ */
+static int uvio_list_secrets(struct uvio_ioctl_cb *uv_ioctl)
+{
+ void __user *user_buf_arg = (void __user *)uv_ioctl->argument_addr;
+ struct uv_cb_guest_addr uvcb = {
+ .header.len = sizeof(uvcb),
+ .header.cmd = UVC_CMD_LIST_SECRETS,
+ };
+ void *secrets = NULL;
+ int ret;
int ret = 0;
+
+ if (uv_ioctl->argument_len != UVIO_LIST_SECRETS_LEN)
+ return -EINVAL;
I'd be less uneasy if you
s/uv_ioctl->argument_len/UVIO_LIST_SECRETS_LEN/ below. Yes, you check
the length above but it still feels weird to use a variable when we have
a perfectly fine constant just waiting to be used.
+
+ secrets = kvzalloc(uv_ioctl->argument_len, GFP_KERNEL);
+ if (!secrets)
+ return -ENOMEM;
+
+ uvcb.addr = (u64)secrets;
+ uv_call_sched(0, (u64)&uvcb);
+ uv_ioctl->uv_rc = uvcb.header.rc;
+ uv_ioctl->uv_rrc = uvcb.header.rrc;
+
+ if (copy_to_user(user_buf_arg, secrets, uv_ioctl->argument_len))
+ ret = -EFAULT;
and remove the else
+ else
+ ret = 0;
+
+ kvfree(secrets);
+ return ret;
+}
+
static int uvio_copy_and_check_ioctl(struct uvio_ioctl_cb *ioctl, void __user *argp,
unsigned long cmd)
{
@@ -333,6 +385,9 @@ static long uvio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
case UVIO_IOCTL_ADD_SECRET_NR:
ret = uvio_add_secret(&uv_ioctl);
break;
+ case UVIO_IOCTL_LIST_SECRETS_NR:
+ ret = uvio_list_secrets(&uv_ioctl);
+ break;
default:
ret = -ENOIOCTLCMD;
break;
