[RFC PATCH 04/19] btrfs: allow encrypted volumes to be mounted

[Mark Harmstone]

Signed-off-by: Mark Harmstone <mark@xxxxxxxxxxxxx>
---
 fs/btrfs/ctree.h        |  3 ++-
 fs/btrfs/encryption.h   | 20 ++++++++++++++++++++
 fs/btrfs/tree-checker.c | 39 +++++++++++++++++++++++++++++----------
 3 files changed, 51 insertions(+), 11 deletions(-)
 create mode 100644 fs/btrfs/encryption.h

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index bd2e59dd0eba..723e9b38e0aa 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -265,7 +265,8 @@ struct btrfs_super_block {
 	 BTRFS_FEATURE_INCOMPAT_RAID56 |		\
 	 BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF |		\
 	 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |	\
-	 BTRFS_FEATURE_INCOMPAT_NO_HOLES)
+	 BTRFS_FEATURE_INCOMPAT_NO_HOLES |		\
+	 BTRFS_FEATURE_INCOMPAT_ENCRYPTION)
 
 #define BTRFS_FEATURE_INCOMPAT_SAFE_SET			\
 	(BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
diff --git a/fs/btrfs/encryption.h b/fs/btrfs/encryption.h
new file mode 100644
index 000000000000..b9a37e76e4a6
--- /dev/null
+++ b/fs/btrfs/encryption.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 Mark Harmstone.  All rights reserved.
+ */
+
+#ifndef BTRFS_ENCRYPTION_H
+#define BTRFS_ENCRYPTION_H
+
+enum btrfs_encryption_type {
+	BTRFS_ENCRYPTION_NONE       = 0,
+	BTRFS_ENCRYPTION_AES256CTR  = 1,
+	BTRFS_ENCRYPTION_TYPES      = 1,
+};
+
+struct btrfs_encryption_header {
+	u64 key_number;
+	u8 iv[BTRFS_ENCRYPTION_BLOCK_LENGTH];
+};
+
+#endif
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index 1a4e2b101ef2..c4fe1cb65d73 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -20,6 +20,7 @@
 #include "disk-io.h"
 #include "compression.h"
 #include "volumes.h"
+#include "encryption.h"
 
 /*
  * Error message should follow the following format:
@@ -140,10 +141,11 @@ static int check_extent_data_item(struct btrfs_fs_info *fs_info,
 			BTRFS_COMPRESS_TYPES);
 		return -EUCLEAN;
 	}
-	if (btrfs_file_extent_encryption(leaf, fi)) {
+	if (btrfs_file_extent_encryption(leaf, fi) > BTRFS_ENCRYPTION_TYPES) {
 		file_extent_err(fs_info, leaf, slot,
-			"invalid encryption for file extent, have %u expect 0",
-			btrfs_file_extent_encryption(leaf, fi));
+	"invalid encryption for file extent, have %u expect range [0, %u]",
+			btrfs_file_extent_encryption(leaf, fi),
+			BTRFS_ENCRYPTION_TYPES);
 		return -EUCLEAN;
 	}
 	if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
@@ -155,9 +157,14 @@ static int check_extent_data_item(struct btrfs_fs_info *fs_info,
 			return -EUCLEAN;
 		}
 
-		/* Compressed inline extent has no on-disk size, skip it */
+		/*
+		 * Compressed or encrypted inline extent has no on-disk size,
+		 * skip it
+		 */
 		if (btrfs_file_extent_compression(leaf, fi) !=
-		    BTRFS_COMPRESS_NONE)
+			BTRFS_COMPRESS_NONE ||
+			btrfs_file_extent_encryption(leaf, fi) !=
+			BTRFS_ENCRYPTION_NONE)
 			return 0;
 
 		/* Uncompressed inline extent size must match item size */
@@ -172,13 +179,25 @@ static int check_extent_data_item(struct btrfs_fs_info *fs_info,
 		return 0;
 	}
 
-	/* Regular or preallocated extent has fixed item size */
-	if (item_size != sizeof(*fi)) {
-		file_extent_err(fs_info, leaf, slot,
+	if (btrfs_file_extent_encryption(leaf, fi) == BTRFS_ENCRYPTION_NONE) {
+		/* Regular or preallocated extent has fixed item size */
+		if (item_size != sizeof(*fi)) {
+			file_extent_err(fs_info, leaf, slot,
 	"invalid item size for reg/prealloc file extent, have %u expect %zu",
-			item_size, sizeof(*fi));
-		return -EUCLEAN;
+				item_size, sizeof(*fi));
+			return -EUCLEAN;
+		}
+	} else {
+		if (item_size !=
+			sizeof(*fi) + sizeof(struct btrfs_encryption_header)) {
+			file_extent_err(fs_info, leaf, slot,
+	"invalid item size for encrypted file extent, have %u expect %zu",
+			  item_size,
+			  sizeof(*fi) + sizeof(struct btrfs_encryption_header));
+			return -EUCLEAN;
+		}
 	}
+
 	if (CHECK_FE_ALIGNED(fs_info, leaf, slot, fi, ram_bytes, sectorsize) ||
 	    CHECK_FE_ALIGNED(fs_info, leaf, slot, fi, disk_bytenr, sectorsize) ||
 	    CHECK_FE_ALIGNED(fs_info, leaf, slot, fi, disk_num_bytes, sectorsize) ||
-- 
2.19.2