handle.c: add kdbus_copy_from_user() helper

Add a little helper to check for 8-byte aligment as well as doing
the actual copy_from_user(). Use it from location where we used to
open-code the same functionality.

Signed-off-by: Daniel Mack <daniel@zonque.org>

diff --git a/handle.c b/handle.c
index 389789952dc709a688cd20de32747ac48bc0c2fb..a32033b4d16acd5312de648c045eab8399f34fe9 100644 (file)
--- a/handle.c
+++ b/handle.c
@@ -206,6 +206,19 @@ static bool kdbus_check_flags(u64 kernel_flags)
        return upper_32_bits(kernel_flags) == 0;
 }
 
+static int kdbus_copy_from_user(void *dest,
+                               void __user *user_ptr,
+                               size_t size)
+{
+       if (!KDBUS_IS_ALIGNED8((uintptr_t)user_ptr))
+               return -EFAULT;
+
+       if (copy_from_user(dest, user_ptr, size))
+               return -EFAULT;
+
+       return 0;
+}
+
 static int kdbus_memdup_user(void __user *user_ptr,
                             void **out,
                             size_t size_min,
@@ -213,12 +226,11 @@ static int kdbus_memdup_user(void __user *user_ptr,
 {
        void *ptr = NULL;
        u64 size;
+       int ret;
 
-       if (!KDBUS_IS_ALIGNED8((uintptr_t) user_ptr))
-               return -EFAULT;
-
-       if (copy_from_user(&size, user_ptr, sizeof(size)))
-               return -EFAULT;
+       ret = kdbus_copy_from_user(&size, user_ptr, sizeof(size));
+       if (ret < 0)
+               return ret;
 
        if (size < size_min)
                return -EINVAL;
@@ -641,13 +653,8 @@ static long kdbus_handle_ioctl_ep_connected(struct file *file, unsigned int cmd,
        case KDBUS_CMD_NAME_LIST: {
                struct kdbus_cmd_name_list cmd_list;
 
-               if (!KDBUS_IS_ALIGNED8((uintptr_t)buf)) {
-                       ret = -EFAULT;
-                       break;
-               }
-
                /* query current IDs and names */
-               if (copy_from_user(&cmd_list, buf, sizeof(cmd_list))) {
+               if (kdbus_copy_from_user(&cmd_list, buf, sizeof(cmd_list))) {
                        ret = -EFAULT;
                        break;
                }
@@ -811,16 +818,10 @@ static long kdbus_handle_ioctl_ep_connected(struct file *file, unsigned int cmd,
                        break;
                }
 
-               if (!KDBUS_IS_ALIGNED8((uintptr_t)buf)) {
-                       ret = -EFAULT;
-                       break;
-               }
-
                /* handle a queued message */
-               if (copy_from_user(&cmd_recv, buf, sizeof(cmd_recv))) {
-                       ret = -EFAULT;
+               ret = kdbus_copy_from_user(&cmd_recv, buf, sizeof(cmd_recv));
+               if (ret < 0)
                        break;
-               }
 
                ret = kdbus_cmd_msg_recv(conn, &cmd_recv);
                if (ret < 0)
@@ -842,16 +843,11 @@ static long kdbus_handle_ioctl_ep_connected(struct file *file, unsigned int cmd,
                        break;
                }
 
-               if (!KDBUS_IS_ALIGNED8((uintptr_t)buf)) {
-                       ret = -EFAULT;
-                       break;
-               }
-
                /* cancel sync message send requests by cookie */
-               if (copy_from_user(&cmd_cancel, buf, sizeof(cmd_cancel))) {
-                       ret = -EFAULT;
+               ret = kdbus_copy_from_user(&cmd_cancel, buf,
+                                          sizeof(cmd_cancel));
+               if (ret < 0)
                        break;
-               }
 
                ret = kdbus_cmd_msg_cancel(conn, cmd_cancel.cookie);
                break;
@@ -866,16 +862,10 @@ static long kdbus_handle_ioctl_ep_connected(struct file *file, unsigned int cmd,
                        break;
                }
 
-               if (!KDBUS_IS_ALIGNED8((uintptr_t)buf)) {
-                       ret = -EFAULT;
-                       break;
-               }
-
                /* free the memory used in the receiver's pool */
-               if (copy_from_user(&cmd_free, buf, sizeof(cmd_free))) {
-                       ret = -EFAULT;
+               ret = copy_from_user(&cmd_free, buf, sizeof(cmd_free));
+               if (ret < 0)
                        break;
-               }
 
                ret = kdbus_pool_release_offset(conn->pool, cmd_free.offset);
                break;