fscrypto: move ioctl processing more fully into common code

Multiple bugs were recently fixed in the "set encryption policy" ioctl.
To make it clear that fscrypt_process_policy() and fscrypt_get_policy()
implement ioctls and therefore their implementations must take standard
security and correctness precautions, rename them to
fscrypt_ioctl_set_policy() and fscrypt_ioctl_get_policy().  Make the
latter take in a struct file * to make it consistent with the former.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 5 insertions, 29 deletions

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index bf5ae8ebbc97..70083863ce51 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -765,22 +765,12 @@ resizefs_out:
 	}
 	case EXT4_IOC_PRECACHE_EXTENTS:
 		return ext4_ext_precache(inode);
-	case EXT4_IOC_SET_ENCRYPTION_POLICY: {
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-		struct fscrypt_policy policy;
 
+	case EXT4_IOC_SET_ENCRYPTION_POLICY:
 		if (!ext4_has_feature_encrypt(sb))
 			return -EOPNOTSUPP;
+		return fscrypt_ioctl_set_policy(filp, (const void __user *)arg);
 
-		if (copy_from_user(&policy,
-				   (struct fscrypt_policy __user *)arg,
-				   sizeof(policy)))
-			return -EFAULT;
-		return fscrypt_process_policy(filp, &policy);
-#else
-		return -EOPNOTSUPP;
-#endif
-	}
 	case EXT4_IOC_GET_ENCRYPTION_PWSALT: {
 		int err, err2;
 		struct ext4_sb_info *sbi = EXT4_SB(sb);
@@ -817,23 +807,9 @@ resizefs_out:
 			return -EFAULT;
 		return 0;
 	}
-	case EXT4_IOC_GET_ENCRYPTION_POLICY: {
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-		struct fscrypt_policy policy;
-		int err = 0;
-
-		if (!ext4_encrypted_inode(inode))
-			return -ENOENT;
-		err = fscrypt_get_policy(inode, &policy);
-		if (err)
-			return err;
-		if (copy_to_user((void __user *)arg, &policy, sizeof(policy)))
-			return -EFAULT;
-		return 0;
-#else
-		return -EOPNOTSUPP;
-#endif
-	}
+	case EXT4_IOC_GET_ENCRYPTION_POLICY:
+		return fscrypt_ioctl_get_policy(filp, (void __user *)arg);
+
 	case EXT4_IOC_FSGETXATTR:
 	{
 		struct fsxattr fa;