On Wed, 13 Mar 2013 17:25:41 -0400 (EDT)
John Mark Walker <
address@hidden> wrote:
> This marks an interesting development in GlusterFS. If you've been
> looking for data encryption, you may want to try this patch.
>
> -JM
>
>
> -------- Original Message --------
> Subject: Change in glusterfs[master]: Transparent data
> encryption and metadata authentication... From: "Edward Shishkin
> (Code Review)" <
address@hidden> To:
> CC:
>
>
>
>
> Edward Shishkin has uploaded a new change for review.
>
> Change subject: Transparent data encryption and metadata
> authentication in the systems with non-trusted
> server ......................................................................
>
> Transparent data encryption and metadata authentication
> in the systems with non-trusted server
>
> This new functionality can be useful in various cloud technologies.
> It is implemented via a pair of the following interacting translators:
>
> . encryption/crypt, which works on client side and performs encryption
> and authentication;
> . features/oplock, which works on server side and resolves "conflicts"
>
> 1. The class of algorithms for data encryption,
> that can be supported by this pair of translators
>
> The mentioned pair of translators can support any atomic symmetric
> block cipher algorithms (which require to pad plain/cipher text before
> performing encryption/decryption transform (see glossary in atom.c
> for definitions). In particular, it can support algorithms with the
> EOF issue (which require to pad the end of file by extra-data).
>
> In most cases crypt translator translates the pair (offset, count)
> passed by user to different values, and resolves individual ->write()
> ->truncate(), etc. file operations to read-modify-write sequences.
>
> A volume can contain files encrypted by different algorithms. For
> newly created files one can specify desirable algorithm at mount time
> via a respective option of crypt translator.
>
> Currently only one algorithm is supported: AES_XTS.
>
> Example of algorithms, which can not be supported by this pair of
> translators:
>
> 1. Asymmetric block cipher algorithms, which inflate data, e.g. RSA;
> 2. Symmetric block cipher algorithms with inline MACs for data
> authentication.
>
> 2. Implementation notes.
>
> a) Atomic algorithms
>
> Since any process in a stackable file system manipulates with local
> data (which can be obsoleted by local data of another process), atomic
> cipher algorithms without proper support can lead to non-POSIX
> behavior. To resolve the "collisions" we introduce a special helper
> translator (features/oplock), which works on the server and manages
> requests (queues, grants access) of read/write issued by the clients.
> When an exclusive access is granted to client, the last one performs
> cipher transform and proceeds the stack. After all the client's work
> is done on the server, the oplock translator drops the access, and
> wakes up the next request in the queue (if any). Our implementation
> guarantees that an access will be granted to every concurrent process,
> which accesses the same file (i.e. the process won't hang).
>
> b) Algorithms with EOF issue
>
> Such algorithms require to pad the end of file with some extra-data.
> Without proper support this will result in losing information about
> real file size. Keeping a track of real file size is a responsibility
> of the mentioned features/oplock translator. When writing/truncating a
> file, the oplock translator cuts the padding and stores the last one
> as a special extended attribute with the key "trusted.ceof". When
> reading a file, oplock translator appends the respective padding. So,
> in the bricks every file has its real size.
>
> Comment. This makes transparent encryption incompatible with GlusterFS
> striping and replication translators, which spawn extra-writes to
> stripe/replica files without due interaction with the oplock
> translator.
>
> 3. Non-trusted servers and
> Metadata authentication
>
> We assume that server, where user's data is stored on is non-trusted.
> It means that the server can be subjected to various attacks directed
> to reveal user's encrypted personal data. We provide protection
> against such attacks.
>
> Every encrypted file has specific private attributes (cipher algorithm
> id, atom size, trusted object id, etc), which are packed to a string
> (so-called "format string") and stored as a special extended attribute
> with the key "trusted.cfmt". We protect the string from tampering.
> This protection is mandatory, hardcoded and is always on. Without such
> protection various attacks (based on extending the scope of per-file
> secret keys) are possible.
>
> Our authentication method has been developed in tight collaboration
> with Red Hat security team and is implemented as "metadata loader of
> version 1" (see file metadata.c). This method is NIST-compliant and is
> based on checking 8-byte per-link MACs created(updated) by
> FOP->create(), FOP->link(), FOP->unlink(), FOP->rename() by the
> following unique entities:
>
> . link name;
> . trusted file's uuid, specially created on the (trusted) client side
>
> Every time, before manipulating with a file, we check it's MACs at
> FOP->open() time. Some FOPs don't require a file to be opened (e.g.
> FOP->truncate()). In such cases the crypt translator opens the file
> mandatory.
>
> 4. Generating keys
>
> Unique per-file keys are derived by NIST-compliant methods (file
> keys.c) from the
>
> a) parent key;
> b) unique trusted object-id of the file;
>
> Per-volume master key, provided by user at mount time is in the root
> of this "tree of keys".
>
> Those keys are used to:
>
> 1) encrypt/decrypt file data;
> 2) encrypt/decrypt file metadata;
> 3) create per-file and per-link MACs for metadata authentication.
>
> 5. Instructions
> how to use the new functionality
>
> 1) Specify an option "encrypt" when creating a volume.
>
> Example:
> # gluster volume create myvol encrypt pepelac:/root/exp8
>
> 2) On the client side, when mounting a volume, specify the absolute
> name of the file, which contains per-volume master key, overriding
> the option "key" of the crypt translator. This file should contain
> 256-bit AES key in the hex form, i.e. 64 symbols. Crypt translator
> accepts the first 64 symbols of the specified file.
> Other extra-symbols are ignored.
> After successful mount the file with master key may be removed.
>
> Example:
> # glusterfs --xlator-option=myvol-crypt.key=/home/edward/mykey \
> --volfile-id=myvol --volfile-server=pepelac /mnt/gluster
>
> WARNING! Losing the master key means losing the data of the whole
> volume without any chances to recovery.
>
> 6. Options of the crypt translator
>
> . "key" (specifies names of the file which contains per-volume master
> key); . "kbits" (specifies size of per-file key for data encryption),
> possible values:
> . "256" default value
> . "512"
> . "blocksize" (specifies the atom size), possible values:
> . "512"
> . "1024"
> . "2048"
> . "4096" default value;
> . id of algorithm for data encryption (hidden option);
> . id of metadata loader (hidden option);
>
> 7. Test cases
>
> Any workload, which involves the following file operations:
>
> ->create();
> ->open();
> ->readv();
> ->writev();
> ->truncate();
> ->ftruncate();
> ->link();
> ->unlink();
> ->rename();
>
> 8. TODOs:
>
> 1) Currently iov_len coincides with atom_size (4K by default). We can
> introduce larger units for IOs to improve performance.
>
> 2) Show encryption status (on/off) of the volume in gluster volume
> info.
>
> Change-Id: I2601fe95c5c4dc5b22308a53d0cbdc071d5e5cee
> Signed-off-by: Edward Shishkin <
address@hidden>
> ---
> M cli/src/cli-cmd-parser.c
> M
configure.ac
> M doc/gluster.8
> M xlators/encryption/Makefile.am
> A xlators/encryption/crypt/Makefile.am
> A xlators/encryption/crypt/src/Makefile.am
> A xlators/encryption/crypt/src/atom.c
> A xlators/encryption/crypt/src/crypt-common.h
> A xlators/encryption/crypt/src/crypt-mem-types.h
> A xlators/encryption/crypt/src/crypt.c
> A xlators/encryption/crypt/src/crypt.h
> A xlators/encryption/crypt/src/data.c
> A xlators/encryption/crypt/src/keys.c
> A xlators/encryption/crypt/src/metadata.c
> A xlators/encryption/crypt/src/metadata.h
> M xlators/features/Makefile.am
> A xlators/features/oplock/Makefile.am
> A xlators/features/oplock/src/Makefile.am
> A xlators/features/oplock/src/oplock-mem-types.h
> A xlators/features/oplock/src/oplock.c
> A xlators/features/oplock/src/oplock.h
> M xlators/mgmt/glusterd/src/glusterd-volgen.c
> M xlators/mgmt/glusterd/src/glusterd-volume-ops.c
> M xlators/mgmt/glusterd/src/glusterd.h
> 24 files changed, 10,159 insertions(+), 19 deletions(-)
>
>
> git pull ssh://
git.gluster.org/glusterfs refs/changes/67/4667/1
> --
> To view, visit
http://review.gluster.org/4667
> To unsubscribe, visit
http://review.gluster.org/settings
>
> Gerrit-MessageType: newchange
> Gerrit-Change-Id: I2601fe95c5c4dc5b22308a53d0cbdc071d5e5cee
> Gerrit-PatchSet: 1
> Gerrit-Project: glusterfs
> Gerrit-Branch: master
> Gerrit-Owner: Edward Shishkin <
address@hidden>