summary refs log tree commit diff
path: root/fs/ext4/super.c
diff options
context:
space:
mode:
authorMichael Halcrow <mhalcrow@google.com>2015-04-12 00:43:56 -0400
committerTheodore Ts'o <tytso@mit.edu>2015-04-12 00:43:56 -0400
commitb30ab0e03407d2aa2d9316cba199c757e4bfc8ad (patch)
tree900754eb3fe069f90bb5ea2c1df1ed88cf701eb5 /fs/ext4/super.c
parent9bd8212f981ea6375911fe055382ad7529be5b28 (diff)
downloadlinux-b30ab0e03407d2aa2d9316cba199c757e4bfc8ad.tar.gz
ext4 crypto: add ext4 encryption facilities
On encrypt, we will re-assign the buffer_heads to point to a bounce
page rather than the control_page (which is the original page to write
that contains the plaintext). The block I/O occurs against the bounce
page.  On write completion, we re-assign the buffer_heads to the
original plaintext page.

On decrypt, we will attach a read completion callback to the bio
struct. This read completion will decrypt the read contents in-place
prior to setting the page up-to-date.

The current encryption mode, AES-256-XTS, lacks cryptographic
integrity. AES-256-GCM is in-plan, but we will need to devise a
mechanism for handling the integrity data.

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Ildar Muslukhov <ildarm@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/super.c')
-rw-r--r--fs/ext4/super.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e47a552fea05..1008ca258de4 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -876,6 +876,9 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
 	atomic_set(&ei->i_ioend_count, 0);
 	atomic_set(&ei->i_unwritten, 0);
 	INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+	ei->i_encryption_key.mode = EXT4_ENCRYPTION_MODE_INVALID;
+#endif
 
 	return &ei->vfs_inode;
 }
@@ -3431,6 +3434,11 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	if (sb->s_bdev->bd_part)
 		sbi->s_sectors_written_start =
 			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+	/* Modes of operations for file and directory encryption. */
+	sbi->s_file_encryption_mode = EXT4_ENCRYPTION_MODE_AES_256_XTS;
+	sbi->s_dir_encryption_mode = EXT4_ENCRYPTION_MODE_INVALID;
+#endif
 
 	/* Cleanup superblock name */
 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)