Native Encryption for ZFS on Linux

This change incorporates three major pieces:

The first change is a keystore that manages wrapping
and encryption keys for encrypted datasets. These
commands mostly involve manipulating the new
DSL Crypto Key ZAP Objects that live in the MOS. Each
encrypted dataset has its own DSL Crypto Key that is
protected with a user's key. This level of indirection
allows users to change their keys without re-encrypting
their entire datasets. The change implements the new
subcommands "zfs load-key", "zfs unload-key" and
"zfs change-key" which allow the user to manage their
encryption keys and settings. In addition, several new
flags and properties have been added to allow dataset
creation and to make mounting and unmounting more
convenient.

The second piece of this patch provides the ability to
encrypt, decyrpt, and authenticate protected datasets.
Each object set maintains a Merkel tree of Message
Authentication Codes that protect the lower layers,
similarly to how checksums are maintained. This part
impacts the zio layer, which handles the actual
encryption and generation of MACs, as well as the ARC
and DMU, which need to be able to handle encrypted
buffers and protected data.

The last addition is the ability to do raw, encrypted
sends and receives. The idea here is to send raw
encrypted and compressed data and receive it exactly
as is on a backup system. This means that the dataset
on the receiving system is protected using the same
user key that is in use on the sending side. By doing
so, datasets can be efficiently backed up to an
untrusted system without fear of data being
compromised.

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #494 
Closes #5769

include/libzfs_core.h

@@ -49,13 +49,17 @@ enum lzc_dataset_type {
 };
 
 int lzc_snapshot(nvlist_t *, nvlist_t *, nvlist_t **);
-int lzc_create(const char *, enum lzc_dataset_type, nvlist_t *);
+int lzc_create(const char *, enum lzc_dataset_type, nvlist_t *, uint8_t *,
+    uint_t);
 int lzc_clone(const char *, const char *, nvlist_t *);
 int lzc_promote(const char *, char *, int);
 int lzc_destroy_snaps(nvlist_t *, boolean_t, nvlist_t **);
 int lzc_bookmark(nvlist_t *, nvlist_t **);
 int lzc_get_bookmarks(const char *, nvlist_t *, nvlist_t **);
 int lzc_destroy_bookmarks(nvlist_t *, nvlist_t **);
+int lzc_load_key(const char *, boolean_t, uint8_t *, uint_t);
+int lzc_unload_key(const char *);
+int lzc_change_key(const char *, uint64_t, nvlist_t *, uint8_t *, uint_t);
 
 int lzc_snaprange_space(const char *, const char *, uint64_t *);
 
@@ -66,7 +70,8 @@ int lzc_get_holds(const char *, nvlist_t **);
 enum lzc_send_flags {
 	LZC_SEND_FLAG_EMBED_DATA = 1 << 0,
 	LZC_SEND_FLAG_LARGE_BLOCK = 1 << 1,
-	LZC_SEND_FLAG_COMPRESS = 1 << 2
+	LZC_SEND_FLAG_COMPRESS = 1 << 2,
+	LZC_SEND_FLAG_RAW = 1 << 3,
 };
 
 int lzc_send(const char *, const char *, int, enum lzc_send_flags);
@@ -76,17 +81,19 @@ int lzc_send_space(const char *, const char *, enum lzc_send_flags, uint64_t *);
 
 struct dmu_replay_record;
 
-int lzc_receive(const char *, nvlist_t *, const char *, boolean_t, int);
-int lzc_receive_resumable(const char *, nvlist_t *, const char *,
+int lzc_receive(const char *, nvlist_t *, const char *, boolean_t, boolean_t,
+    int);
+int lzc_receive_resumable(const char *, nvlist_t *, const char *, boolean_t,
     boolean_t, int);
 int lzc_receive_with_header(const char *, nvlist_t *, const char *, boolean_t,
-    boolean_t, int, const struct dmu_replay_record *);
+    boolean_t, boolean_t, int, const struct dmu_replay_record *);
 int lzc_receive_one(const char *, nvlist_t *, const char *, boolean_t,
-    boolean_t, int, const struct dmu_replay_record *, int, uint64_t *,
-    uint64_t *, uint64_t *, nvlist_t **);
+    boolean_t, boolean_t, int, const struct dmu_replay_record *, int,
+    uint64_t *, uint64_t *, uint64_t *, nvlist_t **);
 int lzc_receive_with_cmdprops(const char *, nvlist_t *, nvlist_t *,
-    const char *, boolean_t, boolean_t, int, const struct dmu_replay_record *,
-    int, uint64_t *, uint64_t *, uint64_t *, nvlist_t **);
+    const char *, boolean_t, boolean_t, boolean_t, int,
+    const struct dmu_replay_record *, int, uint64_t *, uint64_t *,
+    uint64_t *, nvlist_t **);
 
 boolean_t lzc_exists(const char *);