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, 93 insertions, 30 deletions

diff --git a/module/zfs/dsl_dataset.c b/module/zfs/dsl_dataset.c
index bd03b4868..478995a4e 100644
--- a/module/zfs/dsl_dataset.c
+++ b/module/zfs/dsl_dataset.c
@@ -386,8 +386,8 @@ dsl_dataset_try_add_ref(dsl_pool_t *dp, dsl_dataset_t *ds, void *tag)
 }
 
 int
-dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, void *tag,
-    dsl_dataset_t **dsp)
+dsl_dataset_hold_obj_flags(dsl_pool_t *dp, uint64_t dsobj,
+    ds_hold_flags_t flags, void *tag, dsl_dataset_t **dsp)
 {
 	objset_t *mos = dp->dp_meta_objset;
 	dmu_buf_t *dbuf;
@@ -548,11 +548,27 @@ dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, void *tag,
 	    spa_version(dp->dp_spa) < SPA_VERSION_ORIGIN ||
 	    dp->dp_origin_snap == NULL || ds == dp->dp_origin_snap);
 	*dsp = ds;
+
+	if ((flags & DS_HOLD_FLAG_DECRYPT) && ds->ds_dir->dd_crypto_obj != 0) {
+		err = spa_keystore_create_mapping(dp->dp_spa, ds, ds);
+		if (err != 0) {
+			dsl_dataset_rele(ds, tag);
+			return (SET_ERROR(EACCES));
+		}
+	}
+
 	return (0);
 }
 
 int
-dsl_dataset_hold(dsl_pool_t *dp, const char *name,
+dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, void *tag,
+    dsl_dataset_t **dsp)
+{
+	return (dsl_dataset_hold_obj_flags(dp, dsobj, 0, tag, dsp));
+}
+
+int
+dsl_dataset_hold_flags(dsl_pool_t *dp, const char *name, ds_hold_flags_t flags,
     void *tag, dsl_dataset_t **dsp)
 {
 	dsl_dir_t *dd;
@@ -568,7 +584,7 @@ dsl_dataset_hold(dsl_pool_t *dp, const char *name,
 	ASSERT(dsl_pool_config_held(dp));
 	obj = dsl_dir_phys(dd)->dd_head_dataset_obj;
 	if (obj != 0)
-		err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
+		err = dsl_dataset_hold_obj_flags(dp, obj, flags, tag, &ds);
 	else
 		err = SET_ERROR(ENOENT);
 
@@ -577,16 +593,18 @@ dsl_dataset_hold(dsl_pool_t *dp, const char *name,
 		dsl_dataset_t *snap_ds;
 
 		if (*snapname++ != '@') {
-			dsl_dataset_rele(ds, tag);
+			dsl_dataset_rele_flags(ds, flags, tag);
 			dsl_dir_rele(dd, FTAG);
 			return (SET_ERROR(ENOENT));
 		}
 
 		dprintf("looking for snapshot '%s'\n", snapname);
 		err = dsl_dataset_snap_lookup(ds, snapname, &obj);
-		if (err == 0)
-			err = dsl_dataset_hold_obj(dp, obj, tag, &snap_ds);
-		dsl_dataset_rele(ds, tag);
+		if (err == 0) {
+			err = dsl_dataset_hold_obj_flags(dp, obj, flags, tag,
+			    &snap_ds);
+		}
+		dsl_dataset_rele_flags(ds, flags, tag);
 
 		if (err == 0) {
 			mutex_enter(&snap_ds->ds_lock);
@@ -604,14 +622,21 @@ dsl_dataset_hold(dsl_pool_t *dp, const char *name,
 }
 
 int
-dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj,
+dsl_dataset_hold(dsl_pool_t *dp, const char *name, void *tag,
+    dsl_dataset_t **dsp)
+{
+	return (dsl_dataset_hold_flags(dp, name, 0, tag, dsp));
+}
+
+int
+dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj, ds_hold_flags_t flags,
     void *tag, dsl_dataset_t **dsp)
 {
-	int err = dsl_dataset_hold_obj(dp, dsobj, tag, dsp);
+	int err = dsl_dataset_hold_obj_flags(dp, dsobj, flags, tag, dsp);
 	if (err != 0)
 		return (err);
 	if (!dsl_dataset_tryown(*dsp, tag)) {
-		dsl_dataset_rele(*dsp, tag);
+		dsl_dataset_rele_flags(*dsp, flags, tag);
 		*dsp = NULL;
 		return (SET_ERROR(EBUSY));
 	}
@@ -619,14 +644,14 @@ dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj,
 }
 
 int
-dsl_dataset_own(dsl_pool_t *dp, const char *name,
+dsl_dataset_own(dsl_pool_t *dp, const char *name, ds_hold_flags_t flags,
     void *tag, dsl_dataset_t **dsp)
 {
-	int err = dsl_dataset_hold(dp, name, tag, dsp);
+	int err = dsl_dataset_hold_flags(dp, name, flags, tag, dsp);
 	if (err != 0)
 		return (err);
 	if (!dsl_dataset_tryown(*dsp, tag)) {
-		dsl_dataset_rele(*dsp, tag);
+		dsl_dataset_rele_flags(*dsp, flags, tag);
 		return (SET_ERROR(EBUSY));
 	}
 	return (0);
@@ -707,13 +732,25 @@ dsl_dataset_namelen(dsl_dataset_t *ds)
 }
 
 void
-dsl_dataset_rele(dsl_dataset_t *ds, void *tag)
+dsl_dataset_rele_flags(dsl_dataset_t *ds, ds_hold_flags_t flags, void *tag)
 {
+	if (ds->ds_dir != NULL && ds->ds_dir->dd_crypto_obj != 0 &&
+	    (flags & DS_HOLD_FLAG_DECRYPT)) {
+		(void) spa_keystore_remove_mapping(ds->ds_dir->dd_pool->dp_spa,
+		    ds->ds_object, ds);
+	}
+
 	dmu_buf_rele(ds->ds_dbuf, tag);
 }
 
 void
-dsl_dataset_disown(dsl_dataset_t *ds, void *tag)
+dsl_dataset_rele(dsl_dataset_t *ds, void *tag)
+{
+	dsl_dataset_rele_flags(ds, 0, tag);
+}
+
+void
+dsl_dataset_disown(dsl_dataset_t *ds, ds_hold_flags_t flags, void *tag)
 {
 	ASSERT3P(ds->ds_owner, ==, tag);
 	ASSERT(ds->ds_dbuf != NULL);
@@ -722,7 +759,7 @@ dsl_dataset_disown(dsl_dataset_t *ds, void *tag)
 	ds->ds_owner = NULL;
 	mutex_exit(&ds->ds_lock);
 	dsl_dataset_long_rele(ds, tag);
-	dsl_dataset_rele(ds, tag);
+	dsl_dataset_rele_flags(ds, flags, tag);
 }
 
 boolean_t
@@ -751,7 +788,7 @@ dsl_dataset_has_owner(dsl_dataset_t *ds)
 	return (rv);
 }
 
-static void
+void
 dsl_dataset_activate_feature(uint64_t dsobj, spa_feature_t f, dmu_tx_t *tx)
 {
 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
@@ -781,7 +818,7 @@ dsl_dataset_deactivate_feature(uint64_t dsobj, spa_feature_t f, dmu_tx_t *tx)
 
 uint64_t
 dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
-    uint64_t flags, dmu_tx_t *tx)
+    dsl_crypto_params_t *dcp, uint64_t flags, dmu_tx_t *tx)
 {
 	dsl_pool_t *dp = dd->dd_pool;
 	dmu_buf_t *dbuf;
@@ -881,6 +918,9 @@ dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
 		}
 	}
 
+	/* handle encryption */
+	dsl_dataset_create_crypt_sync(dsobj, dd, origin, dcp, tx);
+
 	if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
 		dsphys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
 
@@ -903,6 +943,8 @@ dsl_dataset_zero_zil(dsl_dataset_t *ds, dmu_tx_t *tx)
 		zio_t *zio;
 
 		bzero(&os->os_zil_header, sizeof (os->os_zil_header));
+		if (os->os_encrypted)
+			os->os_next_write_raw = B_TRUE;
 
 		zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
 		dsl_dataset_sync(ds, zio, tx);
@@ -916,7 +958,8 @@ dsl_dataset_zero_zil(dsl_dataset_t *ds, dmu_tx_t *tx)
 
 uint64_t
 dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname,
-    dsl_dataset_t *origin, uint64_t flags, cred_t *cr, dmu_tx_t *tx)
+    dsl_dataset_t *origin, uint64_t flags, cred_t *cr,
+    dsl_crypto_params_t *dcp, dmu_tx_t *tx)
 {
 	dsl_pool_t *dp = pdd->dd_pool;
 	uint64_t dsobj, ddobj;
@@ -928,7 +971,7 @@ dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname,
 	ddobj = dsl_dir_create_sync(dp, pdd, lastname, tx);
 	VERIFY0(dsl_dir_hold_obj(dp, ddobj, lastname, FTAG, &dd));
 
-	dsobj = dsl_dataset_create_sync_dd(dd, origin,
+	dsobj = dsl_dataset_create_sync_dd(dd, origin, dcp,
 	    flags & ~DS_CREATE_FLAG_NODIRTY, tx);
 
 	dsl_deleg_set_create_perms(dd, tx, cr);
@@ -1821,6 +1864,10 @@ get_receive_resume_stats(dsl_dataset_t *ds, nvlist_t *nv)
 		    DS_FIELD_RESUME_COMPRESSOK) == 0) {
 			fnvlist_add_boolean(token_nv, "compressok");
 		}
+		if (zap_contains(dp->dp_meta_objset, ds->ds_object,
+		    DS_FIELD_RESUME_RAWOK) == 0) {
+			fnvlist_add_boolean(token_nv, "rawok");
+		}
 		packed = fnvlist_pack(token_nv, &packed_size);
 		fnvlist_free(token_nv);
 		compressed = kmem_alloc(packed_size, KM_SLEEP);
@@ -1851,6 +1898,7 @@ get_receive_resume_stats(dsl_dataset_t *ds, nvlist_t *nv)
 void
 dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
 {
+	int err;
 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
 	uint64_t refd, avail, uobjs, aobjs, ratio;
 
@@ -1901,12 +1949,12 @@ dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
 	    ds->ds_userrefs);
 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_DEFER_DESTROY,
 	    DS_IS_DEFER_DESTROY(ds) ? 1 : 0);
+	dsl_dataset_crypt_stats(ds, nv);
 
 	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 		uint64_t written, comp, uncomp;
 		dsl_pool_t *dp = ds->ds_dir->dd_pool;
 		dsl_dataset_t *prev;
-		int err;
 
 		err = dsl_dataset_hold_obj(dp,
 		    dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
@@ -2340,7 +2388,7 @@ dsl_dataset_rollback_sync(void *arg, dmu_tx_t *tx)
 	fnvlist_add_string(ddra->ddra_result, "target", namebuf);
 
 	cloneobj = dsl_dataset_create_sync(ds->ds_dir, "%rollback",
-	    ds->ds_prev, DS_CREATE_FLAG_NODIRTY, kcred, tx);
+	    ds->ds_prev, DS_CREATE_FLAG_NODIRTY, kcred, NULL, tx);
 
 	VERIFY0(dsl_dataset_hold_obj(dp, cloneobj, FTAG, &clone));
 
@@ -2427,6 +2475,23 @@ dsl_dataset_promote_check(void *arg, dmu_tx_t *tx)
 		return (SET_ERROR(EXDEV));
 	}
 
+	snap = list_head(&ddpa->shared_snaps);
+	if (snap == NULL) {
+		err = SET_ERROR(ENOENT);
+		goto out;
+	}
+	origin_ds = snap->ds;
+
+	/*
+	 * Encrypted clones share a DSL Crypto Key with their origin's dsl dir.
+	 * When doing a promote we must make sure the encryption root for
+	 * both the target and the target's origin does not change to avoid
+	 * needing to rewrap encryption keys
+	 */
+	err = dsl_dataset_promote_crypt_check(hds->ds_dir, origin_ds->ds_dir);
+	if (err != 0)
+		goto out;
+
 	/*
 	 * Compute and check the amount of space to transfer.  Since this is
 	 * so expensive, don't do the preliminary check.
@@ -2436,13 +2501,6 @@ dsl_dataset_promote_check(void *arg, dmu_tx_t *tx)
 		return (0);
 	}
 
-	snap = list_head(&ddpa->shared_snaps);
-	if (snap == NULL) {
-		err = SET_ERROR(ENOENT);
-		goto out;
-	}
-	origin_ds = snap->ds;
-
 	/* compute origin's new unique space */
 	snap = list_tail(&ddpa->clone_snaps);
 	ASSERT3U(dsl_dataset_phys(snap->ds)->ds_prev_snap_obj, ==,
@@ -2611,6 +2669,8 @@ dsl_dataset_promote_sync(void *arg, dmu_tx_t *tx)
 	VERIFY0(dsl_dir_hold_obj(dp, origin_ds->ds_dir->dd_object,
 	    NULL, FTAG, &odd));
 
+	dsl_dataset_promote_crypt_sync(hds->ds_dir, odd, tx);
+
 	/* change origin's next snap */
 	dmu_buf_will_dirty(origin_ds->ds_dbuf, tx);
 	oldnext_obj = dsl_dataset_phys(origin_ds)->ds_next_snap_obj;
@@ -3692,11 +3752,14 @@ MODULE_PARM_DESC(zfs_max_recordsize, "Max allowed record size");
 #endif
 
 EXPORT_SYMBOL(dsl_dataset_hold);
+EXPORT_SYMBOL(dsl_dataset_hold_flags);
 EXPORT_SYMBOL(dsl_dataset_hold_obj);
+EXPORT_SYMBOL(dsl_dataset_hold_obj_flags);
 EXPORT_SYMBOL(dsl_dataset_own);
 EXPORT_SYMBOL(dsl_dataset_own_obj);
 EXPORT_SYMBOL(dsl_dataset_name);
 EXPORT_SYMBOL(dsl_dataset_rele);
+EXPORT_SYMBOL(dsl_dataset_rele_flags);
 EXPORT_SYMBOL(dsl_dataset_disown);
 EXPORT_SYMBOL(dsl_dataset_tryown);
 EXPORT_SYMBOL(dsl_dataset_create_sync);