From ae76f45cda0e0857f99e53959cf71c7a5d66bd8b Mon Sep 17 00:00:00 2001 From: Tom Caputi Date: Wed, 8 Nov 2017 14:12:59 -0500 Subject: Encryption Stability and On-Disk Format Fixes The on-disk format for encrypted datasets protects not only the encrypted and authenticated blocks themselves, but also the order and interpretation of these blocks. In order to make this work while maintaining the ability to do raw sends, the indirect bps maintain a secure checksum of all the MACs in the block below it along with a few other fields that determine how the data is interpreted. Unfortunately, the current on-disk format erroneously includes some fields which are not portable and thus cannot support raw sends. It is not possible to easily work around this issue due to a separate and much smaller bug which causes indirect blocks for encrypted dnodes to not be compressed, which conflicts with the previous bug. In addition, the current code generates incompatible on-disk formats on big endian and little endian systems due to an issue with how block pointers are authenticated. Finally, raw send streams do not currently include dn_maxblkid when sending both the metadnode and normal dnodes which are needed in order to ensure that we are correctly maintaining the portable objset MAC. This patch zero's out the offending fields when computing the bp MAC and ensures that these MACs are always calculated in little endian order (regardless of the host system's byte order). This patch also registers an errata for the old on-disk format, which we detect by adding a "version" field to newly created DSL Crypto Keys. We allow datasets without a version (version 0) to only be mounted for read so that they can easily be migrated. We also now include dn_maxblkid in raw send streams to ensure the MAC can be maintained correctly. This patch also contains minor bug fixes and cleanups. Reviewed-by: Jorgen Lundman Reviewed-by: Brian Behlendorf Reviewed by: Matthew Ahrens Signed-off-by: Tom Caputi Closes #6845 Closes #6864 Closes #7052 --- include/sys/dnode.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include/sys/dnode.h') diff --git a/include/sys/dnode.h b/include/sys/dnode.h index e5e39b18c..a2bef9d2c 100644 --- a/include/sys/dnode.h +++ b/include/sys/dnode.h @@ -221,6 +221,13 @@ typedef struct dnode_phys { uint64_t dn_maxblkid; /* largest allocated block ID */ uint64_t dn_used; /* bytes (or sectors) of disk space */ + /* + * Both dn_pad2 and dn_pad3 are protected by the block's MAC. This + * allows us to protect any fields that might be added here in the + * future. In either case, developers will want to check + * zio_crypt_init_uios_dnode() to ensure the new field is being + * protected properly. + */ uint64_t dn_pad3[4]; /* @@ -301,6 +308,7 @@ struct dnode { uint8_t dn_rm_spillblk[TXG_SIZE]; /* for removing spill blk */ uint16_t dn_next_bonuslen[TXG_SIZE]; uint32_t dn_next_blksz[TXG_SIZE]; /* next block size in bytes */ + uint64_t dn_next_maxblkid[TXG_SIZE]; /* next maxblkid in bytes */ /* protected by dn_dbufs_mtx; declared here to fill 32-bit hole */ uint32_t dn_dbufs_count; /* count of dn_dbufs */ -- cgit v1.2.3