autofs4 copy_dev_ioctl(): keep the value of ->size we'd used for allo…

…cation X-Coverup: just ask spender Cc: [email protected] Signed-off-by: Al Viro <[email protected]>
xlks · Feb 22, 2015 · 0a28096 · 0a28096
1 parent 7e0e953
commit 0a28096
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
@@ -95,7 +95,7 @@ static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param)
  */
 static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *in)
 {
-	struct autofs_dev_ioctl tmp;
+	struct autofs_dev_ioctl tmp, *res;
 
 	if (copy_from_user(&tmp, in, sizeof(tmp)))
 		return ERR_PTR(-EFAULT);
@@ -106,7 +106,11 @@ static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *i
 	if (tmp.size > (PATH_MAX + sizeof(tmp)))
 		return ERR_PTR(-ENAMETOOLONG);
 
-	return memdup_user(in, tmp.size);
+	res = memdup_user(in, tmp.size);
+	if (!IS_ERR(res))
+		res->size = tmp.size;
+
+	return res;
 }
 
 static inline void free_dev_ioctl(struct autofs_dev_ioctl *param)