The goal is to leave only protocol-defined items in gss_krb5.h so
that it can be easily replaced by a generic header. Implementation
specific items are moved to the new internal header.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
RFC 6803 defines two encryption types that use Camellia ciphers (RFC
3713) and CMAC digests. Implement support for those in SunRPC's GSS
Kerberos 5 mechanism.
There has not been an explicit request to support these enctypes.
However, this new set of enctypes provides a good alternative to the
AES-SHA1 enctypes that are to be deprecated at some point.
As this implementation is still a "beta", the default is to not
build it automatically.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Fill in entries in the supported_gss_krb5_enctypes array for the
encryption types defined in RFC 8009. These new enctypes use the
SHA-256 and SHA-384 message digest algorithms (as defined in
FIPS-180) instead of the deprecated SHA-1 algorithm, and are thus
more secure.
Note that NIST has scheduled SHA-1 for deprecation:
https://www.nist.gov/news-events/news/2022/12/nist-retires-sha-1-cryptographic-algorithm
Thus these new encryption types are placed under a separate CONFIG
option to enable distributors to separately introduce support for
the AES-SHA2 enctypes and deprecate support for the current set of
AES-SHA1 encryption types as their user space allows.
As this implementation is still a "beta", the default is to not
build it automatically.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The aes256-cts-hmac-sha384-192 enctype specifies the length of its
checksum and integrity subkeys as 192 bits, but the length of its
encryption subkey (Ke) as 256 bits. Add new fields to struct
gss_krb5_enctype that specify the key lengths individually, and
where needed, use the correct new field instead of ->keylength.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Each Kerberos enctype can have a different KDF. Refactor the key
derivation path to support different KDFs for the enctypes
introduced in subsequent patches.
In particular, expose the key derivation function in struct
gss_krb5_enctype instead of the enctype's preferred random-to-key
function. The latter is usually the identity function and is only
ever called during key derivation, so have each KDF call it
directly.
A couple of extra clean-ups:
- Deduplicate the set_cdata() helper
- Have ->derive_key return negative errnos, in accordance with usual
kernel coding conventions
This patch is a little bigger than I'd like, but these are all
mechanical changes and they are all to the same areas of code. No
behavior change is intended.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Clean up: there is now only one encrypt and only one decrypt method,
thus there is no longer a need for the v2-suffixed method names.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Clean up: ->encrypt is set to only one value. Replace the two
remaining call sites with direct calls to krb5_encrypt().
There have never been any call sites for the ->decrypt() method.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Replace another switch on encryption type so that it does not have
to be modified when adding or removing support for an enctype.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Replace a number of switches on encryption type so that all of them don't
have to be modified when adding or removing support for an enctype.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
There's no need to keep the integrity keys around if we instead
allocate and key a pair of ahashes and keep those. This not only
enables the subkeys to be destroyed immediately after deriving
them, but it makes the Kerberos integrity code path more efficient.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
There's no need to keep the signing keys around if we instead allocate
and key an ahash and keep that. This not only enables the subkeys to
be destroyed immediately after deriving them, but it makes the
Kerberos signing code path more efficient.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The encryption subkeys are not used after the cipher transforms have
been allocated and keyed. There is no need to retain them in struct
krb5_ctx.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Hoist the name of the aux_cipher into struct gss_krb5_enctype to
prepare for obscuring the encryption keys just after they are
derived.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Other common Kerberos implementations use a fully random confounder
for encryption. The reason for this is explained in the new comment
added by this patch. The current get_random_bytes() implementation
does not exhaust system entropy.
Since confounder generation is part of Kerberos itself rather than
the GSS-API Kerberos mechanism, the function is renamed and moved.
Note that light top-down analysis shows that the SHA-1 transform
is by far the most CPU-intensive part of encryption. Thus we do not
expect this change to result in a significant performance impact.
However, eventually it might be necessary to generate an independent
stream of confounders for each Kerberos context to help improve I/O
parallelism.
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Now that arcfour-hmac is gone, the confounder length is again the
same as the cipher blocksize for every implemented enctype. The
gss_krb5_enctype::conflen field is no longer necessary.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
It is not clear from documenting comments, specifications, or code
usage what value the gss_krb5_enctype.blocksize field is supposed
to store. The "encryption blocksize" depends only on the cipher
being used, so that value can be derived where it's needed instead
of stored as a constant.
RFC 3961 Section 5.2 says:
> cipher block size, c
> This is the block size of the block cipher underlying the
> encryption and decryption functions indicated above, used for key
> derivation and for the size of the message confounder and initial
> vector. (If a block cipher is not in use, some comparable
> parameter should be determined.) It must be at least 5 octets.
>
> This is not actually an independent parameter; rather, it is a
> property of the functions E and D. It is listed here to clarify
> the distinction between it and the message block size, m.
In the Linux kernel's implemenation of the SunRPC RPCSEC GSS
Kerberos 5 mechanism, the cipher block size, which is dependent on
the encryption and decryption transforms, is used only in
krb5_derive_key(), so it is straightforward to replace it.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Standard convention: Ensure the contents of the header are included
only once per source file.
Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The RC4-HMAC-MD5 KerberosV algorithm is based on RFC 4757 [0], which
was specifically issued for interoperability with Windows 2000, but was
never intended to receive the same level of support. The RFC says
The IETF Kerberos community supports publishing this specification as
an informational document in order to describe this widely
implemented technology. However, while these encryption types
provide the operations necessary to implement the base Kerberos
specification [RFC4120], they do not provide all the required
operations in the Kerberos cryptography framework [RFC3961]. As a
result, it is not generally possible to implement potential
extensions to Kerberos using these encryption types. The Kerberos
encryption type negotiation mechanism [RFC4537] provides one approach
for using such extensions even when a Kerberos infrastructure uses
long-term RC4 keys. Because this specification does not implement
operations required by RFC 3961 and because of security concerns with
the use of RC4 and MD4 discussed in Section 8, this specification is
not appropriate for publication on the standards track.
The RC4-HMAC encryption types are used to ease upgrade of existing
Windows NT environments, provide strong cryptography (128-bit key
lengths), and provide exportable (meet United States government
export restriction requirements) encryption. This document describes
the implementation of those encryption types.
Furthermore, this RFC was re-classified as 'historic' by RFC 8429 [1] in
2018, stating that 'none of the encryption types it specifies should be
used'
Note that other outdated algorithms are left in place (some of which are
guarded by CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES), so this should only
adversely affect interoperability with Windows NT/2000 systems that have
not received any updates since 2008 (but are connected to a network
nonetheless)
[0] https://tools.ietf.org/html/rfc4757
[1] https://tools.ietf.org/html/rfc8429
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Refactor: This is a pre-requisite to fixing the client-side ralign
computation in gss_unwrap_resp_priv().
The length value is passed in explicitly rather that as the value
of buf->len. This will subsequently allow gss_unwrap_kerberos_v1()
to compute a slack and align value, instead of computing it in
gss_unwrap_resp_priv().
Fixes: 35e77d21ba ("SUNRPC: Add rpc_auth::au_ralign field")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Using signed 32-bit types for UTC time leads to the y2038 overflow,
which is what happens in the sunrpc code at the moment.
This changes the sunrpc code over to use time64_t where possible.
The one exception is the gss_import_v{1,2}_context() function for
kerberos5, which uses 32-bit timestamps in the protocol. Here,
we can at least treat the numbers as 'unsigned', which extends the
range from 2038 to 2106.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Pull NFS client bugfixes from Trond Myklebust:
"Highlights include:
Bugfix:
- Fix build issues on architectures that don't provide 64-bit cmpxchg
Cleanups:
- Fix a spelling mistake"
* tag 'nfs-for-4.20-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
NFS: fix spelling mistake, EACCESS -> EACCES
SUNRPC: Use atomic(64)_t for seq_send(64)
The seq_send & seq_send64 fields in struct krb5_ctx are used as
atomically incrementing counters. This is implemented using cmpxchg() &
cmpxchg64() to implement what amount to custom versions of
atomic_fetch_inc() & atomic64_fetch_inc().
Besides the duplication, using cmpxchg64() has another major drawback in
that some 32 bit architectures don't provide it. As such commit
571ed1fd23 ("SUNRPC: Replace krb5_seq_lock with a lockless scheme")
resulted in build failures for some architectures.
Change seq_send to be an atomic_t and seq_send64 to be an atomic64_t,
then use atomic(64)_* functions to manipulate the values. The atomic64_t
type & associated functions are provided even on architectures which
lack real 64 bit atomic memory access via CONFIG_GENERIC_ATOMIC64 which
uses spinlocks to serialize access. This fixes the build failures for
architectures lacking cmpxchg64().
A potential alternative that was raised would be to provide cmpxchg64()
on the 32 bit architectures that currently lack it, using spinlocks.
However this would provide a version of cmpxchg64() with semantics a
little different to the implementations on architectures with real 64
bit atomics - the spinlock-based implementation would only work if all
access to the memory used with cmpxchg64() is *always* performed using
cmpxchg64(). That is not currently a requirement for users of
cmpxchg64(), and making it one seems questionable. As such avoiding
cmpxchg64() outside of architecture-specific code seems best,
particularly in cases where atomic64_t seems like a better fit anyway.
The CONFIG_GENERIC_ATOMIC64 implementation of atomic64_* functions will
use spinlocks & so faces the same issue, but with the key difference
that the memory backing an atomic64_t ought to always be accessed via
the atomic64_* functions anyway making the issue moot.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Fixes: 571ed1fd23 ("SUNRPC: Replace krb5_seq_lock with a lockless scheme")
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Pull NFS client updates from Trond Myklebust:
"Highlights include:
Stable fixes:
- Fix the NFSv4.1 r/wsize sanity checking
- Reset the RPC/RDMA credit grant properly after a disconnect
- Fix a missed page unlock after pg_doio()
Features and optimisations:
- Overhaul of the RPC client socket code to eliminate a locking
bottleneck and reduce the latency when transmitting lots of
requests in parallel.
- Allow parallelisation of the RPCSEC_GSS encoding of an RPC request.
- Convert the RPC client socket receive code to use iovec_iter() for
improved efficiency.
- Convert several NFS and RPC lookup operations to use RCU instead of
taking global locks.
- Avoid the need for BH-safe locks in the RPC/RDMA back channel.
Bugfixes and cleanups:
- Fix lock recovery during NFSv4 delegation recalls
- Fix the NFSv4 + NFSv4.1 "lookup revalidate + open file" case.
- Fixes for the RPC connection metrics
- Various RPC client layer cleanups to consolidate stream based
sockets
- RPC/RDMA connection cleanups
- Simplify the RPC/RDMA cleanup after memory operation failures
- Clean ups for NFS v4.2 copy completion and NFSv4 open state
reclaim"
* tag 'nfs-for-4.20-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (97 commits)
SUNRPC: Convert the auth cred cache to use refcount_t
SUNRPC: Convert auth creds to use refcount_t
SUNRPC: Simplify lookup code
SUNRPC: Clean up the AUTH cache code
NFS: change sign of nfs_fh length
sunrpc: safely reallow resvport min/max inversion
nfs: remove redundant call to nfs_context_set_write_error()
nfs: Fix a missed page unlock after pg_doio()
SUNRPC: Fix a compile warning for cmpxchg64()
NFSv4.x: fix lock recovery during delegation recall
SUNRPC: use cmpxchg64() in gss_seq_send64_fetch_and_inc()
xprtrdma: Squelch a sparse warning
xprtrdma: Clean up xprt_rdma_disconnect_inject
xprtrdma: Add documenting comments
xprtrdma: Report when there were zero posted Receives
xprtrdma: Move rb_flags initialization
xprtrdma: Don't disable BH's in backchannel server
xprtrdma: Remove memory address of "ep" from an error message
xprtrdma: Rename rpcrdma_qp_async_error_upcall
xprtrdma: Simplify RPC wake-ups on connect
...
This patch replaces uses of blkcipher with skcipher and the long
obsolete hash interface with either shash (for non-SG users) and
ahash.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Again, we can deadlock if the memory reclaim triggers a writeback that
requires a rpcsec_gss credential lookup.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add necessary changes to add kernel support for the rc4-hmac Kerberos
encryption type used by Microsoft and described in rfc4757.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
All encryption types use a confounder at the beginning of the
wrap token. In all encryption types except arcfour-hmac, the
confounder is the same as the blocksize. arcfour-hmac has a
blocksize of one, but uses an eight byte confounder.
Add an entry to the crypto framework definitions for the
confounder length and change the wrap/unwrap code to use
the confounder length rather than assuming it is always
the blocksize.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
For the arcfour-hmac support, the make_seq_num and get_seq_num
functions need access to the kerberos context structure.
This will be used in a later patch.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This is needed for deriving arcfour-hmac keys "on the fly"
using the sequence number or checksu
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
For arcfour-hmac support, the make_checksum function needs a usage
field to correctly calculate the checksum differently for MIC and
WRAP tokens.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This is a step toward support for AES encryption types which are
required to use the new token formats defined in rfc4121.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
[SteveD: Fixed a typo in gss_verify_mic_v2()]
Signed-off-by: Steve Dickson <steved@redhat.com>
[Trond: Got rid of the TEST_ROTATE/TEST_EXTRA_COUNT crap]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
For encryption types other than DES, gssd sends down context information
in a new format. This new format includes the information needed to
support the new Kerberos GSS-API tokens defined in rfc4121.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Import the code to derive Kerberos keys from a base key into the
kernel. This will allow us to change the format of the context
information sent down from gssd to include only a single key.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Encryption types besides DES may use a keyed checksum (hmac).
Modify the make_checksum() function to allow for a key
and take care of enctype-specific processing such as truncating
the resulting hash.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add enctype framework and change functions to use the generic
values from it rather than the values hard-coded for des.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add encryption type to the krb5 context structure and use it to switch
to the correct functions depending on the encryption type.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Make the client and server code consistent regarding the extra buffer
space made available for the auth code when wrapping data.
Add some comments/documentation about the available buffer space
in the xdr_buf head and tail when gss_wrap is called.
Add a compile-time check to make sure we are not exceeding the available
buffer space.
Add a central function to shift head data.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
cleanup:
Document token header size with a #define instead of open-coding it.
Don't needlessly increment "ptr" past the beginning of the header
which makes the values passed to functions more understandable and
eliminates the need for extra "krb5_hdr" pointer.
Clean up some intersecting white-space issues flagged by checkpatch.pl.
This leaves the checksum length hard-coded at 8 for DES. A later patch
cleans that up.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Consistently use unsigned (u32 vs. s32) for seqnum.
In get_mic function, send the local copy of seq_send,
rather than the context version.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
cleanup: When adding new encryption types, the checksum length
can be different for each enctype. Face the fact that the
current code only supports DES which has a checksum length of 8.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
The sealalg is checked in several places, giving the impression it could be
either SEAL_ALG_NONE or SEAL_ALG_DES. But in fact SEAL_ALG_NONE seems to
be sufficient only for making mic's, and all the contexts we get must be
capable of wrapping as well. So the sealalg must be SEAL_ALG_DES. As
with signalg, just check for the right value on the downcall and ignore it
otherwise. Similarly, tighten expectations for the sealalg on incoming
tokens, in case we do support other values eventually.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We're doing some pointless translation between krb5 constants and kernel
crypto string names.
Also clean up some related spkm3 code as necessary.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We designed the krb5 context import without completely understanding the
context. Now it's clear that there are a number of fields that we ignore,
or that we depend on having one single value.
In particular, we only support one value of signalg currently; so let's
check the signalg field in the downcall (in case we decide there's
something else we could support here eventually), but ignore it otherwise.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
