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 <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Jorgen Lundman <[email protected]>
Signed-off-by: Tom Caputi <[email protected]>
Closes #494 
Closes #5769 

1 files changed, 55 insertions, 14 deletions

diff --git a/include/sys/arc.h b/include/sys/arc.h
index 07a72302d..6edf4ea56 100644
--- a/include/sys/arc.h
+++ b/include/sys/arc.h
@@ -60,15 +60,26 @@ _NOTE(CONSTCOND) } while (0)
 typedef struct arc_buf_hdr arc_buf_hdr_t;
 typedef struct arc_buf arc_buf_t;
 typedef struct arc_prune arc_prune_t;
-typedef void arc_done_func_t(zio_t *zio, arc_buf_t *buf, void *private);
+
+/*
+ * Because the ARC can store encrypted data, errors (not due to bugs) may arise
+ * while transforming data into its desired format - specifically, when
+ * decrypting, the key may not be present, or the HMAC may not be correct
+ * which signifies deliberate tampering with the on-disk state
+ * (assuming that the checksum was correct). The "error" parameter will be
+ * nonzero in this case, even if there is no associated zio.
+ */
+typedef void arc_read_done_func_t(zio_t *zio, int error, arc_buf_t *buf,
+    void *private);
+typedef void arc_write_done_func_t(zio_t *zio, arc_buf_t *buf, void *private);
 typedef void arc_prune_func_t(int64_t bytes, void *private);
 
 /* Shared module parameters */
 extern int zfs_arc_average_blocksize;
 
 /* generic arc_done_func_t's which you can use */
-arc_done_func_t arc_bcopy_func;
-arc_done_func_t arc_getbuf_func;
+arc_read_done_func_t arc_bcopy_func;
+arc_read_done_func_t arc_getbuf_func;
 
 /* generic arc_prune_func_t wrapper for callbacks */
 struct arc_prune {
@@ -110,20 +121,29 @@ typedef enum arc_flags
 	ARC_FLAG_L2_WRITING		= 1 << 11,	/* write in progress */
 	ARC_FLAG_L2_EVICTED		= 1 << 12,	/* evicted during I/O */
 	ARC_FLAG_L2_WRITE_HEAD		= 1 << 13,	/* head of write list */
+	/*
+	 * Encrypted or authenticated on disk (may be plaintext in memory).
+	 * This header has b_crypt_hdr allocated. Does not include indirect
+	 * blocks with checksums of MACs which will also have their X
+	 * (encrypted) bit set in the bp.
+	 */
+	ARC_FLAG_PROTECTED		= 1 << 14,
+	/* data has not been authenticated yet */
+	ARC_FLAG_NOAUTH			= 1 << 15,
 	/* indicates that the buffer contains metadata (otherwise, data) */
-	ARC_FLAG_BUFC_METADATA		= 1 << 14,
+	ARC_FLAG_BUFC_METADATA		= 1 << 16,
 
 	/* Flags specifying whether optional hdr struct fields are defined */
-	ARC_FLAG_HAS_L1HDR		= 1 << 15,
-	ARC_FLAG_HAS_L2HDR		= 1 << 16,
+	ARC_FLAG_HAS_L1HDR		= 1 << 17,
+	ARC_FLAG_HAS_L2HDR		= 1 << 18,
 
 	/*
 	 * Indicates the arc_buf_hdr_t's b_pdata matches the on-disk data.
 	 * This allows the l2arc to use the blkptr's checksum to verify
 	 * the data without having to store the checksum in the hdr.
 	 */
-	ARC_FLAG_COMPRESSED_ARC		= 1 << 17,
-	ARC_FLAG_SHARED_DATA		= 1 << 18,
+	ARC_FLAG_COMPRESSED_ARC		= 1 << 19,
+	ARC_FLAG_SHARED_DATA		= 1 << 20,
 
 	/*
 	 * The arc buffer's compression mode is stored in the top 7 bits of the
@@ -142,7 +162,12 @@ typedef enum arc_flags
 
 typedef enum arc_buf_flags {
 	ARC_BUF_FLAG_SHARED		= 1 << 0,
-	ARC_BUF_FLAG_COMPRESSED		= 1 << 1
+	ARC_BUF_FLAG_COMPRESSED		= 1 << 1,
+	/*
+	 * indicates whether this arc_buf_t is encrypted, regardless of
+	 * state on-disk
+	 */
+	ARC_BUF_FLAG_ENCRYPTED		= 1 << 2
 } arc_buf_flags_t;
 
 struct arc_buf {
@@ -206,15 +231,31 @@ typedef struct arc_buf_info {
 void arc_space_consume(uint64_t space, arc_space_type_t type);
 void arc_space_return(uint64_t space, arc_space_type_t type);
 boolean_t arc_is_metadata(arc_buf_t *buf);
+boolean_t arc_is_encrypted(arc_buf_t *buf);
+boolean_t arc_is_unauthenticated(arc_buf_t *buf);
 enum zio_compress arc_get_compression(arc_buf_t *buf);
-int arc_decompress(arc_buf_t *buf);
+void arc_get_raw_params(arc_buf_t *buf, boolean_t *byteorder, uint8_t *salt,
+    uint8_t *iv, uint8_t *mac);
+int arc_untransform(arc_buf_t *buf, spa_t *spa, uint64_t dsobj,
+    boolean_t in_place);
+void arc_convert_to_raw(arc_buf_t *buf, uint64_t dsobj, boolean_t byteorder,
+    dmu_object_type_t ot, const uint8_t *salt, const uint8_t *iv,
+    const uint8_t *mac);
 arc_buf_t *arc_alloc_buf(spa_t *spa, void *tag, arc_buf_contents_t type,
     int32_t size);
 arc_buf_t *arc_alloc_compressed_buf(spa_t *spa, void *tag,
     uint64_t psize, uint64_t lsize, enum zio_compress compression_type);
+arc_buf_t *arc_alloc_raw_buf(spa_t *spa, void *tag, uint64_t dsobj,
+    boolean_t byteorder, const uint8_t *salt, const uint8_t *iv,
+    const uint8_t *mac, dmu_object_type_t ot, uint64_t psize, uint64_t lsize,
+    enum zio_compress compression_type);
 arc_buf_t *arc_loan_buf(spa_t *spa, boolean_t is_metadata, int size);
 arc_buf_t *arc_loan_compressed_buf(spa_t *spa, uint64_t psize, uint64_t lsize,
     enum zio_compress compression_type);
+arc_buf_t *arc_loan_raw_buf(spa_t *spa, uint64_t dsobj, boolean_t byteorder,
+    const uint8_t *salt, const uint8_t *iv, const uint8_t *mac,
+    dmu_object_type_t ot, uint64_t psize, uint64_t lsize,
+    enum zio_compress compression_type);
 void arc_return_buf(arc_buf_t *buf, void *tag);
 void arc_loan_inuse_buf(arc_buf_t *buf, void *tag);
 void arc_buf_destroy(arc_buf_t *buf, void *tag);
@@ -231,12 +272,12 @@ int arc_referenced(arc_buf_t *buf);
 #endif
 
 int arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
-    arc_done_func_t *done, void *private, zio_priority_t priority, int flags,
-    arc_flags_t *arc_flags, const zbookmark_phys_t *zb);
+    arc_read_done_func_t *done, void *private, zio_priority_t priority,
+    int flags, arc_flags_t *arc_flags, const zbookmark_phys_t *zb);
 zio_t *arc_write(zio_t *pio, spa_t *spa, uint64_t txg,
     blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, const zio_prop_t *zp,
-    arc_done_func_t *ready, arc_done_func_t *child_ready,
-    arc_done_func_t *physdone, arc_done_func_t *done,
+    arc_write_done_func_t *ready, arc_write_done_func_t *child_ready,
+    arc_write_done_func_t *physdone, arc_write_done_func_t *done,
     void *private, zio_priority_t priority, int zio_flags,
     const zbookmark_phys_t *zb);