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, 35 insertions, 8 deletions

diff --git a/module/zfs/dmu_traverse.c b/module/zfs/dmu_traverse.c
index c78228d74..a6c27b4be 100644
--- a/module/zfs/dmu_traverse.c
+++ b/module/zfs/dmu_traverse.c
@@ -132,7 +132,7 @@ traverse_zil(traverse_data_t *td, zil_header_t *zh)
 	zilog = zil_alloc(spa_get_dsl(td->td_spa)->dp_meta_objset, zh);
 
 	(void) zil_parse(zilog, traverse_zil_block, traverse_zil_record, td,
-	    claim_txg);
+	    claim_txg, !(td->td_flags & TRAVERSE_NO_DECRYPT));
 
 	zil_free(zilog);
 }
@@ -181,6 +181,7 @@ traverse_prefetch_metadata(traverse_data_t *td,
     const blkptr_t *bp, const zbookmark_phys_t *zb)
 {
 	arc_flags_t flags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
+	int zio_flags = ZIO_FLAG_CANFAIL;
 
 	if (!(td->td_flags & TRAVERSE_PREFETCH_METADATA))
 		return;
@@ -196,8 +197,11 @@ traverse_prefetch_metadata(traverse_data_t *td,
 	if (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE)
 		return;
 
+	if ((td->td_flags & TRAVERSE_NO_DECRYPT) && BP_IS_PROTECTED(bp))
+		zio_flags |= ZIO_FLAG_RAW;
+
 	(void) arc_read(NULL, td->td_spa, bp, NULL, NULL,
-	    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
+	    ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
 }
 
 static boolean_t
@@ -294,6 +298,8 @@ traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,
 		int32_t epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
 		zbookmark_phys_t *czb;
 
+		ASSERT(!BP_IS_PROTECTED(bp));
+
 		err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
 		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
 		if (err != 0)
@@ -324,14 +330,23 @@ traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,
 
 	} else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
 		uint32_t flags = ARC_FLAG_WAIT;
+		uint32_t zio_flags = ZIO_FLAG_CANFAIL;
 		int32_t i;
 		int32_t epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
 		dnode_phys_t *child_dnp;
 
+		/*
+		 * dnode blocks might have their bonus buffers encrypted, so
+		 * we must be careful to honor TRAVERSE_NO_DECRYPT
+		 */
+		if ((td->td_flags & TRAVERSE_NO_DECRYPT) && BP_IS_PROTECTED(bp))
+			zio_flags |= ZIO_FLAG_RAW;
+
 		err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
-		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
+		    ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
 		if (err != 0)
 			goto post;
+
 		child_dnp = buf->b_data;
 
 		for (i = 0; i < epb; i += child_dnp[i].dn_extra_slots + 1) {
@@ -347,11 +362,15 @@ traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,
 				break;
 		}
 	} else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
+		uint32_t zio_flags = ZIO_FLAG_CANFAIL;
 		arc_flags_t flags = ARC_FLAG_WAIT;
 		objset_phys_t *osp;
 
+		if ((td->td_flags & TRAVERSE_NO_DECRYPT) && BP_IS_PROTECTED(bp))
+			zio_flags |= ZIO_FLAG_RAW;
+
 		err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
-		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
+		    ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
 		if (err != 0)
 			goto post;
 
@@ -500,6 +519,7 @@ traverse_prefetcher(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
 {
 	prefetch_data_t *pfd = arg;
+	int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE;
 	arc_flags_t aflags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
 
 	ASSERT(pfd->pd_bytes_fetched >= 0);
@@ -518,8 +538,11 @@ traverse_prefetcher(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 	cv_broadcast(&pfd->pd_cv);
 	mutex_exit(&pfd->pd_mtx);
 
+	if ((pfd->pd_flags & TRAVERSE_NO_DECRYPT) && BP_IS_PROTECTED(bp))
+		zio_flags |= ZIO_FLAG_RAW;
+
 	(void) arc_read(NULL, spa, bp, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
-	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, &aflags, zb);
+	    zio_flags, &aflags, zb);
 
 	return (0);
 }
@@ -599,13 +622,17 @@ traverse_impl(spa_t *spa, dsl_dataset_t *ds, uint64_t objset, blkptr_t *rootbp,
 
 	/* See comment on ZIL traversal in dsl_scan_visitds. */
 	if (ds != NULL && !ds->ds_is_snapshot && !BP_IS_HOLE(rootbp)) {
+		enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
 		uint32_t flags = ARC_FLAG_WAIT;
 		objset_phys_t *osp;
 		arc_buf_t *buf;
 
-		err = arc_read(NULL, td->td_spa, rootbp,
-		    arc_getbuf_func, &buf,
-		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, czb);
+		if ((td->td_flags & TRAVERSE_NO_DECRYPT) &&
+		    BP_IS_PROTECTED(rootbp))
+			zio_flags |= ZIO_FLAG_RAW;
+
+		err = arc_read(NULL, td->td_spa, rootbp, arc_getbuf_func,
+		    &buf, ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, czb);
 		if (err != 0)
 			return (err);