Commit Graph

32 Commits

Author SHA1 Message Date
Linus Torvalds
028db3e290 Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs"
This reverts merge 0f75ef6a9c (and thus
effectively commits

   7a1ade8475 ("keys: Provide KEYCTL_GRANT_PERMISSION")
   2e12256b9a ("keys: Replace uid/gid/perm permissions checking with an ACL")

that the merge brought in).

It turns out that it breaks booting with an encrypted volume, and Eric
biggers reports that it also breaks the fscrypt tests [1] and loading of
in-kernel X.509 certificates [2].

The root cause of all the breakage is likely the same, but David Howells
is off email so rather than try to work it out it's getting reverted in
order to not impact the rest of the merge window.

 [1] https://lore.kernel.org/lkml/20190710011559.GA7973@sol.localdomain/
 [2] https://lore.kernel.org/lkml/20190710013225.GB7973@sol.localdomain/

Link: https://lore.kernel.org/lkml/CAHk-=wjxoeMJfeBahnWH=9zShKp2bsVy527vo3_y8HfOdhwAAw@mail.gmail.com/
Reported-by: Eric Biggers <ebiggers@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-10 18:43:43 -07:00
Linus Torvalds
0f75ef6a9c Keyrings ACL
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Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull keyring ACL support from David Howells:
 "This changes the permissions model used by keys and keyrings to be
  based on an internal ACL by the following means:

   - Replace the permissions mask internally with an ACL that contains a
     list of ACEs, each with a specific subject with a permissions mask.
     Potted default ACLs are available for new keys and keyrings.

     ACE subjects can be macroised to indicate the UID and GID specified
     on the key (which remain). Future commits will be able to add
     additional subject types, such as specific UIDs or domain
     tags/namespaces.

     Also split a number of permissions to give finer control. Examples
     include splitting the revocation permit from the change-attributes
     permit, thereby allowing someone to be granted permission to revoke
     a key without allowing them to change the owner; also the ability
     to join a keyring is split from the ability to link to it, thereby
     stopping a process accessing a keyring by joining it and thus
     acquiring use of possessor permits.

   - Provide a keyctl to allow the granting or denial of one or more
     permits to a specific subject. Direct access to the ACL is not
     granted, and the ACL cannot be viewed"

* tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  keys: Provide KEYCTL_GRANT_PERMISSION
  keys: Replace uid/gid/perm permissions checking with an ACL
2019-07-08 19:56:57 -07:00
Linus Torvalds
d44a62742d Keyrings miscellany
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Merge tag 'keys-misc-20190619' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull misc keyring updates from David Howells:
 "These are some miscellaneous keyrings fixes and improvements:

   - Fix a bunch of warnings from sparse, including missing RCU bits and
     kdoc-function argument mismatches

   - Implement a keyctl to allow a key to be moved from one keyring to
     another, with the option of prohibiting key replacement in the
     destination keyring.

   - Grant Link permission to possessors of request_key_auth tokens so
     that upcall servicing daemons can more easily arrange things such
     that only the necessary auth key is passed to the actual service
     program, and not all the auth keys a daemon might possesss.

   - Improvement in lookup_user_key().

   - Implement a keyctl to allow keyrings subsystem capabilities to be
     queried.

  The keyutils next branch has commits to make available, document and
  test the move-key and capabilities code:

        https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git/log

  They're currently on the 'next' branch"

* tag 'keys-misc-20190619' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  keys: Add capability-checking keyctl function
  keys: Reuse keyring_index_key::desc_len in lookup_user_key()
  keys: Grant Link permission to possessers of request_key auth keys
  keys: Add a keyctl to move a key between keyrings
  keys: Hoist locking out of __key_link_begin()
  keys: Break bits out of key_unlink()
  keys: Change keyring_serialise_link_sem to a mutex
  keys: sparse: Fix kdoc mismatches
  keys: sparse: Fix incorrect RCU accesses
  keys: sparse: Fix key_fs[ug]id_changed()
2019-07-08 19:02:11 -07:00
David Howells
7a1ade8475 keys: Provide KEYCTL_GRANT_PERMISSION
Provide a keyctl() operation to grant/remove permissions.  The grant
operation, wrapped by libkeyutils, looks like:

	int ret = keyctl_grant_permission(key_serial_t key,
					  enum key_ace_subject_type type,
					  unsigned int subject,
					  unsigned int perm);

Where key is the key to be modified, type and subject represent the subject
to which permission is to be granted (or removed) and perm is the set of
permissions to be granted.  0 is returned on success.  SET_SECURITY
permission is required for this.

The subject type currently must be KEY_ACE_SUBJ_STANDARD for the moment
(other subject types will come along later).

For subject type KEY_ACE_SUBJ_STANDARD, the following subject values are
available:

	KEY_ACE_POSSESSOR	The possessor of the key
	KEY_ACE_OWNER		The owner of the key
	KEY_ACE_GROUP		The key's group
	KEY_ACE_EVERYONE	Everyone

perm lists the permissions to be granted:

	KEY_ACE_VIEW		Can view the key metadata
	KEY_ACE_READ		Can read the key content
	KEY_ACE_WRITE		Can update/modify the key content
	KEY_ACE_SEARCH		Can find the key by searching/requesting
	KEY_ACE_LINK		Can make a link to the key
	KEY_ACE_SET_SECURITY	Can set security
	KEY_ACE_INVAL		Can invalidate
	KEY_ACE_REVOKE		Can revoke
	KEY_ACE_JOIN		Can join this keyring
	KEY_ACE_CLEAR		Can clear this keyring

If an ACE already exists for the subject, then the permissions mask will be
overwritten; if perm is 0, it will be deleted.

Currently, the internal ACL is limited to a maximum of 16 entries.

For example:

	int ret = keyctl_grant_permission(key,
					  KEY_ACE_SUBJ_STANDARD,
					  KEY_ACE_OWNER,
					  KEY_ACE_VIEW | KEY_ACE_READ);

Signed-off-by: David Howells <dhowells@redhat.com>
2019-07-03 13:05:22 +01:00
David Howells
45e0f30c30 keys: Add capability-checking keyctl function
Add a keyctl function that requests a set of capability bits to find out
what features are supported.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-06-19 13:27:45 +01:00
David Howells
ed0ac5c7ec keys: Add a keyctl to move a key between keyrings
Add a keyctl to atomically move a link to a key from one keyring to
another.  The key must exist in "from" keyring and a flag can be given to
cause the operation to fail if there's a matching key already in the "to"
keyring.

This can be done with:

	keyctl(KEYCTL_MOVE,
	       key_serial_t key,
	       key_serial_t from_keyring,
	       key_serial_t to_keyring,
	       unsigned int flags);

The key being moved must grant Link permission and both keyrings must grant
Write permission.

flags should be 0 or KEYCTL_MOVE_EXCL, with the latter preventing
displacement of a matching key from the "to" keyring.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-05-30 22:44:48 +01:00
Thomas Gleixner
2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00
David Howells
00d60fd3b9 KEYS: Provide keyctls to drive the new key type ops for asymmetric keys [ver #2]
Provide five keyctl functions that permit userspace to make use of the new
key type ops for accessing and driving asymmetric keys.

 (*) Query an asymmetric key.

	long keyctl(KEYCTL_PKEY_QUERY,
		    key_serial_t key, unsigned long reserved,
		    struct keyctl_pkey_query *info);

     Get information about an asymmetric key.  The information is returned
     in the keyctl_pkey_query struct:

	__u32	supported_ops;

     A bit mask of flags indicating which ops are supported.  This is
     constructed from a bitwise-OR of:

	KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}

	__u32	key_size;

     The size in bits of the key.

	__u16	max_data_size;
	__u16	max_sig_size;
	__u16	max_enc_size;
	__u16	max_dec_size;

     The maximum sizes in bytes of a blob of data to be signed, a signature
     blob, a blob to be encrypted and a blob to be decrypted.

     reserved must be set to 0.  This is intended for future use to hand
     over one or more passphrases needed unlock a key.

     If successful, 0 is returned.  If the key is not an asymmetric key,
     EOPNOTSUPP is returned.

 (*) Encrypt, decrypt, sign or verify a blob using an asymmetric key.

	long keyctl(KEYCTL_PKEY_ENCRYPT,
		    const struct keyctl_pkey_params *params,
		    const char *info,
		    const void *in,
		    void *out);

	long keyctl(KEYCTL_PKEY_DECRYPT,
		    const struct keyctl_pkey_params *params,
		    const char *info,
		    const void *in,
		    void *out);

	long keyctl(KEYCTL_PKEY_SIGN,
		    const struct keyctl_pkey_params *params,
		    const char *info,
		    const void *in,
		    void *out);

	long keyctl(KEYCTL_PKEY_VERIFY,
		    const struct keyctl_pkey_params *params,
		    const char *info,
		    const void *in,
		    const void *in2);

     Use an asymmetric key to perform a public-key cryptographic operation
     a blob of data.

     The parameter block pointed to by params contains a number of integer
     values:

	__s32		key_id;
	__u32		in_len;
	__u32		out_len;
	__u32		in2_len;

     For a given operation, the in and out buffers are used as follows:

	Operation ID		in,in_len	out,out_len	in2,in2_len
	=======================	===============	===============	===========
	KEYCTL_PKEY_ENCRYPT	Raw data	Encrypted data	-
	KEYCTL_PKEY_DECRYPT	Encrypted data	Raw data	-
	KEYCTL_PKEY_SIGN	Raw data	Signature	-
	KEYCTL_PKEY_VERIFY	Raw data	-		Signature

     info is a string of key=value pairs that supply supplementary
     information.

     The __spare space in the parameter block must be set to 0.  This is
     intended, amongst other things, to allow the passing of passphrases
     required to unlock a key.

     If successful, encrypt, decrypt and sign all return the amount of data
     written into the output buffer.  Verification returns 0 on success.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Denis Kenzior <denkenz@gmail.com>
Tested-by: Denis Kenzior <denkenz@gmail.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
2018-10-26 09:30:46 +01:00
Stephan Mueller
f1c316a3ab KEYS: add SP800-56A KDF support for DH
SP800-56A defines the use of DH with key derivation function based on a
counter. The input to the KDF is defined as (DH shared secret || other
information). The value for the "other information" is to be provided by
the caller.

The KDF is implemented using the hash support from the kernel crypto API.
The implementation uses the symmetric hash support as the input to the
hash operation is usually very small. The caller is allowed to specify
the hash name that he wants to use to derive the key material allowing
the use of all supported hashes provided with the kernel crypto API.

As the KDF implements the proper truncation of the DH shared secret to
the requested size, this patch fills the caller buffer up to its size.

The patch is tested with a new test added to the keyutils user space
code which uses a CAVS test vector testing the compliance with
SP800-56A.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: David Howells <dhowells@redhat.com>
2017-04-04 22:33:38 +01:00
Mat Martineau
6563c91fd6 KEYS: Add KEYCTL_RESTRICT_KEYRING
Keyrings recently gained restrict_link capabilities that allow
individual keys to be validated prior to linking.  This functionality
was only available using internal kernel APIs.

With the KEYCTL_RESTRICT_KEYRING command existing keyrings can be
configured to check the content of keys before they are linked, and
then allow or disallow linkage of that key to the keyring.

To restrict a keyring, call:

  keyctl(KEYCTL_RESTRICT_KEYRING, key_serial_t keyring, const char *type,
         const char *restriction)

where 'type' is the name of a registered key type and 'restriction' is a
string describing how key linkage is to be restricted. The restriction
option syntax is specific to each key type.

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
2017-04-04 14:10:12 -07:00
Stephan Mueller
4693fc734d KEYS: Add placeholder for KDF usage with DH
The values computed during Diffie-Hellman key exchange are often used
in combination with key derivation functions to create cryptographic
keys.  Add a placeholder for a later implementation to configure a
key derivation function that will transform the Diffie-Hellman
result returned by the KEYCTL_DH_COMPUTE command.

[This patch was stripped down from a patch produced by Mat Martineau that
 had a bug in the compat code - so for the moment Stephan's patch simply
 requires that the placeholder argument must be NULL]

Original-signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2016-06-03 16:14:34 +10:00
Mat Martineau
ddbb411487 KEYS: Add KEYCTL_DH_COMPUTE command
This adds userspace access to Diffie-Hellman computations through a
new keyctl() syscall command to calculate shared secrets or public
keys using input parameters stored in the keyring.

Input key ids are provided in a struct due to the current 5-arg limit
for the keyctl syscall. Only user keys are supported in order to avoid
exposing the content of logon or encrypted keys.

The output is written to the provided buffer, based on the assumption
that the values are only needed in userspace.

Future support for other types of key derivation would involve a new
command, like KEYCTL_ECDH_COMPUTE.

Once Diffie-Hellman support is included in the crypto API, this code
can be converted to use the crypto API to take advantage of possible
hardware acceleration and reduce redundant code.

Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
2016-04-12 19:54:58 +01:00
Al Viro
b353a1f7bb switch keyctl_instantiate_key_common() to iov_iter
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-11 22:27:12 -04:00
Heiko Carstens
875ec3da4c security/compat: convert to COMPAT_SYSCALL_DEFINE
Convert all compat system call functions where all parameter types
have a size of four or less than four bytes, or are pointer types
to COMPAT_SYSCALL_DEFINE.
The implicit casts within COMPAT_SYSCALL_DEFINE will perform proper
zero and sign extension to 64 bit of all parameters if needed.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2014-03-06 16:30:42 +01:00
David Howells
f36f8c75ae KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches
Add support for per-user_namespace registers of persistent per-UID kerberos
caches held within the kernel.

This allows the kerberos cache to be retained beyond the life of all a user's
processes so that the user's cron jobs can work.

The kerberos cache is envisioned as a keyring/key tree looking something like:

	struct user_namespace
	  \___ .krb_cache keyring		- The register
		\___ _krb.0 keyring		- Root's Kerberos cache
		\___ _krb.5000 keyring		- User 5000's Kerberos cache
		\___ _krb.5001 keyring		- User 5001's Kerberos cache
			\___ tkt785 big_key	- A ccache blob
			\___ tkt12345 big_key	- Another ccache blob

Or possibly:

	struct user_namespace
	  \___ .krb_cache keyring		- The register
		\___ _krb.0 keyring		- Root's Kerberos cache
		\___ _krb.5000 keyring		- User 5000's Kerberos cache
		\___ _krb.5001 keyring		- User 5001's Kerberos cache
			\___ tkt785 keyring	- A ccache
				\___ krbtgt/REDHAT.COM@REDHAT.COM big_key
				\___ http/REDHAT.COM@REDHAT.COM user
				\___ afs/REDHAT.COM@REDHAT.COM user
				\___ nfs/REDHAT.COM@REDHAT.COM user
				\___ krbtgt/KERNEL.ORG@KERNEL.ORG big_key
				\___ http/KERNEL.ORG@KERNEL.ORG big_key

What goes into a particular Kerberos cache is entirely up to userspace.  Kernel
support is limited to giving you the Kerberos cache keyring that you want.

The user asks for their Kerberos cache by:

	krb_cache = keyctl_get_krbcache(uid, dest_keyring);

The uid is -1 or the user's own UID for the user's own cache or the uid of some
other user's cache (requires CAP_SETUID).  This permits rpc.gssd or whatever to
mess with the cache.

The cache returned is a keyring named "_krb.<uid>" that the possessor can read,
search, clear, invalidate, unlink from and add links to.  Active LSMs get a
chance to rule on whether the caller is permitted to make a link.

Each uid's cache keyring is created when it first accessed and is given a
timeout that is extended each time this function is called so that the keyring
goes away after a while.  The timeout is configurable by sysctl but defaults to
three days.

Each user_namespace struct gets a lazily-created keyring that serves as the
register.  The cache keyrings are added to it.  This means that standard key
search and garbage collection facilities are available.

The user_namespace struct's register goes away when it does and anything left
in it is then automatically gc'd.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Simo Sorce <simo@redhat.com>
cc: Serge E. Hallyn <serge.hallyn@ubuntu.com>
cc: Eric W. Biederman <ebiederm@xmission.com>
2013-09-24 10:35:19 +01:00
Mathieu Desnoyers
8aec0f5d41 Fix: compat_rw_copy_check_uvector() misuse in aio, readv, writev, and security keys
Looking at mm/process_vm_access.c:process_vm_rw() and comparing it to
compat_process_vm_rw() shows that the compatibility code requires an
explicit "access_ok()" check before calling
compat_rw_copy_check_uvector(). The same difference seems to appear when
we compare fs/read_write.c:do_readv_writev() to
fs/compat.c:compat_do_readv_writev().

This subtle difference between the compat and non-compat requirements
should probably be debated, as it seems to be error-prone. In fact,
there are two others sites that use this function in the Linux kernel,
and they both seem to get it wrong:

Now shifting our attention to fs/aio.c, we see that aio_setup_iocb()
also ends up calling compat_rw_copy_check_uvector() through
aio_setup_vectored_rw(). Unfortunately, the access_ok() check appears to
be missing. Same situation for
security/keys/compat.c:compat_keyctl_instantiate_key_iov().

I propose that we add the access_ok() check directly into
compat_rw_copy_check_uvector(), so callers don't have to worry about it,
and it therefore makes the compat call code similar to its non-compat
counterpart. Place the access_ok() check in the same location where
copy_from_user() can trigger a -EFAULT error in the non-compat code, so
the ABI behaviors are alike on both compat and non-compat.

While we are here, fix compat_do_readv_writev() so it checks for
compat_rw_copy_check_uvector() negative return values.

And also, fix a memory leak in compat_keyctl_instantiate_key_iov() error
handling.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-12 11:05:45 -07:00
James Morris
66dd07b88a Merge commit 'v3.5-rc2' into next 2012-06-10 22:52:10 +10:00
Christopher Yeoh
ac34ebb3a6 aio/vfs: cleanup of rw_copy_check_uvector() and compat_rw_copy_check_uvector()
A cleanup of rw_copy_check_uvector and compat_rw_copy_check_uvector after
changes made to support CMA in an earlier patch.

Rather than having an additional check_access parameter to these
functions, the first paramater type is overloaded to allow the caller to
specify CHECK_IOVEC_ONLY which means check that the contents of the iovec
are valid, but do not check the memory that they point to.  This is used
by process_vm_readv/writev where we need to validate that a iovec passed
to the syscall is valid but do not want to check the memory that it points
to at this point because it refers to an address space in another process.

Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:32 -07:00
David Howells
423b978802 KEYS: Fix some sparse warnings
Fix some sparse warnings in the keyrings code:

 (1) compat_keyctl_instantiate_key_iov() should be static.

 (2) There were a couple of places where a pointer was being compared against
     integer 0 rather than NULL.

 (3) keyctl_instantiate_key_common() should not take a __user-labelled iovec
     pointer as the caller must have copied the iovec to kernel space.

 (4) __key_link_begin() takes and __key_link_end() releases
     keyring_serialise_link_sem under some circumstances and so this should be
     declared.

     Note that adding __acquires() and __releases() for this doesn't help cure
     the warnings messages - something only commenting out both helps.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-05-25 20:51:42 +10:00
David Howells
fd75815f72 KEYS: Add invalidation support
Add support for invalidating a key - which renders it immediately invisible to
further searches and causes the garbage collector to immediately wake up,
remove it from keyrings and then destroy it when it's no longer referenced.

It's better not to do this with keyctl_revoke() as that marks the key to start
returning -EKEYREVOKED to searches when what is actually desired is to have the
key refetched.

To invalidate a key the caller must be granted SEARCH permission by the key.
This may be too strict.  It may be better to also permit invalidation if the
caller has any of READ, WRITE or SETATTR permission.

The primary use for this is to evict keys that are cached in special keyrings,
such as the DNS resolver or an ID mapper.

Signed-off-by: David Howells <dhowells@redhat.com>
2012-05-11 10:56:56 +01:00
Christopher Yeoh
fcf634098c Cross Memory Attach
The basic idea behind cross memory attach is to allow MPI programs doing
intra-node communication to do a single copy of the message rather than a
double copy of the message via shared memory.

The following patch attempts to achieve this by allowing a destination
process, given an address and size from a source process, to copy memory
directly from the source process into its own address space via a system
call.  There is also a symmetrical ability to copy from the current
process's address space into a destination process's address space.

- Use of /proc/pid/mem has been considered, but there are issues with
  using it:
  - Does not allow for specifying iovecs for both src and dest, assuming
    preadv or pwritev was implemented either the area read from or
  written to would need to be contiguous.
  - Currently mem_read allows only processes who are currently
  ptrace'ing the target and are still able to ptrace the target to read
  from the target. This check could possibly be moved to the open call,
  but its not clear exactly what race this restriction is stopping
  (reason  appears to have been lost)
  - Having to send the fd of /proc/self/mem via SCM_RIGHTS on unix
  domain socket is a bit ugly from a userspace point of view,
  especially when you may have hundreds if not (eventually) thousands
  of processes  that all need to do this with each other
  - Doesn't allow for some future use of the interface we would like to
  consider adding in the future (see below)
  - Interestingly reading from /proc/pid/mem currently actually
  involves two copies! (But this could be fixed pretty easily)

As mentioned previously use of vmsplice instead was considered, but has
problems.  Since you need the reader and writer working co-operatively if
the pipe is not drained then you block.  Which requires some wrapping to
do non blocking on the send side or polling on the receive.  In all to all
communication it requires ordering otherwise you can deadlock.  And in the
example of many MPI tasks writing to one MPI task vmsplice serialises the
copying.

There are some cases of MPI collectives where even a single copy interface
does not get us the performance gain we could.  For example in an
MPI_Reduce rather than copy the data from the source we would like to
instead use it directly in a mathops (say the reduce is doing a sum) as
this would save us doing a copy.  We don't need to keep a copy of the data
from the source.  I haven't implemented this, but I think this interface
could in the future do all this through the use of the flags - eg could
specify the math operation and type and the kernel rather than just
copying the data would apply the specified operation between the source
and destination and store it in the destination.

Although we don't have a "second user" of the interface (though I've had
some nibbles from people who may be interested in using it for intra
process messaging which is not MPI).  This interface is something which
hardware vendors are already doing for their custom drivers to implement
fast local communication.  And so in addition to this being useful for
OpenMPI it would mean the driver maintainers don't have to fix things up
when the mm changes.

There was some discussion about how much faster a true zero copy would
go. Here's a link back to the email with some testing I did on that:

http://marc.info/?l=linux-mm&m=130105930902915&w=2

There is a basic man page for the proposed interface here:

http://ozlabs.org/~cyeoh/cma/process_vm_readv.txt

This has been implemented for x86 and powerpc, other architecture should
mainly (I think) just need to add syscall numbers for the process_vm_readv
and process_vm_writev. There are 32 bit compatibility versions for
64-bit kernels.

For arch maintainers there are some simple tests to be able to quickly
verify that the syscalls are working correctly here:

http://ozlabs.org/~cyeoh/cma/cma-test-20110718.tgz

Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: <linux-man@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-31 17:30:44 -07:00
David Howells
ee009e4a0d KEYS: Add an iovec version of KEYCTL_INSTANTIATE
Add a keyctl op (KEYCTL_INSTANTIATE_IOV) that is like KEYCTL_INSTANTIATE, but
takes an iovec array and concatenates the data in-kernel into one buffer.
Since the KEYCTL_INSTANTIATE copies the data anyway, this isn't too much of a
problem.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2011-03-08 11:17:22 +11:00
David Howells
fdd1b94581 KEYS: Add a new keyctl op to reject a key with a specified error code
Add a new keyctl op to reject a key with a specified error code.  This works
much the same as negating a key, and so keyctl_negate_key() is made a special
case of keyctl_reject_key().  The difference is that keyctl_negate_key()
selects ENOKEY as the error to be reported.

Typically the key would be rejected with EKEYEXPIRED, EKEYREVOKED or
EKEYREJECTED, but this is not mandatory.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2011-03-08 11:17:18 +11:00
David Howells
973c9f4f49 KEYS: Fix up comments in key management code
Fix up comments in the key management code.  No functional changes.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-21 14:59:30 -08:00
David Howells
a8b17ed019 KEYS: Do some style cleanup in the key management code.
Do a bit of a style clean up in the key management code.  No functional
changes.

Done using:

  perl -p -i -e 's!^/[*]*/\n!!' security/keys/*.c
  perl -p -i -e 's!} /[*] end [a-z0-9_]*[(][)] [*]/\n!}\n!' security/keys/*.c
  sed -i -s -e ": next" -e N -e 's/^\n[}]$/}/' -e t -e P -e 's/^.*\n//' -e "b next" security/keys/*.c

To remove /*****/ lines, remove comments on the closing brace of a
function to name the function and remove blank lines before the closing
brace of a function.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-21 14:59:29 -08:00
David Howells
ee18d64c1f KEYS: Add a keyctl to install a process's session keyring on its parent [try #6]
Add a keyctl to install a process's session keyring onto its parent.  This
replaces the parent's session keyring.  Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again.  Normally this
will be after a wait*() syscall.

To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.

The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.

Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME.  This allows the
replacement to be performed at the point the parent process resumes userspace
execution.

This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership.  However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.

This can be tested with the following program:

	#include <stdio.h>
	#include <stdlib.h>
	#include <keyutils.h>

	#define KEYCTL_SESSION_TO_PARENT	18

	#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)

	int main(int argc, char **argv)
	{
		key_serial_t keyring, key;
		long ret;

		keyring = keyctl_join_session_keyring(argv[1]);
		OSERROR(keyring, "keyctl_join_session_keyring");

		key = add_key("user", "a", "b", 1, keyring);
		OSERROR(key, "add_key");

		ret = keyctl(KEYCTL_SESSION_TO_PARENT);
		OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");

		return 0;
	}

Compiled and linked with -lkeyutils, you should see something like:

	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: _ses
	355907932 --alswrv   4043    -1   \_ keyring: _uid.4043
	[dhowells@andromeda ~]$ /tmp/newpag
	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: _ses
	1055658746 --alswrv   4043  4043   \_ user: a
	[dhowells@andromeda ~]$ /tmp/newpag hello
	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: hello
	340417692 --alswrv   4043  4043   \_ user: a

Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-09-02 21:29:22 +10:00
David Howells
70a5bb72b5 keys: add keyctl function to get a security label
Add a keyctl() function to get the security label of a key.

The following is added to Documentation/keys.txt:

 (*) Get the LSM security context attached to a key.

	long keyctl(KEYCTL_GET_SECURITY, key_serial_t key, char *buffer,
		    size_t buflen)

     This function returns a string that represents the LSM security context
     attached to a key in the buffer provided.

     Unless there's an error, it always returns the amount of data it could
     produce, even if that's too big for the buffer, but it won't copy more
     than requested to userspace. If the buffer pointer is NULL then no copy
     will take place.

     A NUL character is included at the end of the string if the buffer is
     sufficiently big.  This is included in the returned count.  If no LSM is
     in force then an empty string will be returned.

     A process must have view permission on the key for this function to be
     successful.

[akpm@linux-foundation.org: declare keyctl_get_security()]
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:16 -07:00
Tim Schmielau
cd354f1ae7 [PATCH] remove many unneeded #includes of sched.h
After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there.  Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.

To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.

Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm.  I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).

Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-14 08:09:54 -08:00
David Howells
b5f545c880 [PATCH] keys: Permit running process to instantiate keys
Make it possible for a running process (such as gssapid) to be able to
instantiate a key, as was requested by Trond Myklebust for NFS4.

The patch makes the following changes:

 (1) A new, optional key type method has been added. This permits a key type
     to intercept requests at the point /sbin/request-key is about to be
     spawned and do something else with them - passing them over the
     rpc_pipefs files or netlink sockets for instance.

     The uninstantiated key, the authorisation key and the intended operation
     name are passed to the method.

 (2) The callout_info is no longer passed as an argument to /sbin/request-key
     to prevent unauthorised viewing of this data using ps or by looking in
     /proc/pid/cmdline.

     This means that the old /sbin/request-key program will not work with the
     patched kernel as it will expect to see an extra argument that is no
     longer there.

     A revised keyutils package will be made available tomorrow.

 (3) The callout_info is now attached to the authorisation key. Reading this
     key will retrieve the information.

 (4) A new field has been added to the task_struct. This holds the
     authorisation key currently active for a thread. Searches now look here
     for the caller's set of keys rather than looking for an auth key in the
     lowest level of the session keyring.

     This permits a thread to be servicing multiple requests at once and to
     switch between them. Note that this is per-thread, not per-process, and
     so is usable in multithreaded programs.

     The setting of this field is inherited across fork and exec.

 (5) A new keyctl function (KEYCTL_ASSUME_AUTHORITY) has been added that
     permits a thread to assume the authority to deal with an uninstantiated
     key. Assumption is only permitted if the authorisation key associated
     with the uninstantiated key is somewhere in the thread's keyrings.

     This function can also clear the assumption.

 (6) A new magic key specifier has been added to refer to the currently
     assumed authorisation key (KEY_SPEC_REQKEY_AUTH_KEY).

 (7) Instantiation will only proceed if the appropriate authorisation key is
     assumed first. The assumed authorisation key is discarded if
     instantiation is successful.

 (8) key_validate() is moved from the file of request_key functions to the
     file of permissions functions.

 (9) The documentation is updated.

From: <Valdis.Kletnieks@vt.edu>

    Build fix.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Alexander Zangerl <az@bond.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:53 -08:00
David Howells
017679c4d4 [PATCH] keys: Permit key expiry time to be set
Add a new keyctl function that allows the expiry time to be set on a key or
removed from a key, provided the caller has attribute modification access.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Alexander Zangerl <az@bond.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:53 -08:00
David Howells
3e30148c3d [PATCH] Keys: Make request-key create an authorisation key
The attached patch makes the following changes:

 (1) There's a new special key type called ".request_key_auth".

     This is an authorisation key for when one process requests a key and
     another process is started to construct it. This type of key cannot be
     created by the user; nor can it be requested by kernel services.

     Authorisation keys hold two references:

     (a) Each refers to a key being constructed. When the key being
     	 constructed is instantiated the authorisation key is revoked,
     	 rendering it of no further use.

     (b) The "authorising process". This is either:

     	 (i) the process that called request_key(), or:

     	 (ii) if the process that called request_key() itself had an
     	      authorisation key in its session keyring, then the authorising
     	      process referred to by that authorisation key will also be
     	      referred to by the new authorisation key.

	 This means that the process that initiated a chain of key requests
	 will authorise the lot of them, and will, by default, wind up with
	 the keys obtained from them in its keyrings.

 (2) request_key() creates an authorisation key which is then passed to
     /sbin/request-key in as part of a new session keyring.

 (3) When request_key() is searching for a key to hand back to the caller, if
     it comes across an authorisation key in the session keyring of the
     calling process, it will also search the keyrings of the process
     specified therein and it will use the specified process's credentials
     (fsuid, fsgid, groups) to do that rather than the calling process's
     credentials.

     This allows a process started by /sbin/request-key to find keys belonging
     to the authorising process.

 (4) A key can be read, even if the process executing KEYCTL_READ doesn't have
     direct read or search permission if that key is contained within the
     keyrings of a process specified by an authorisation key found within the
     calling process's session keyring, and is searchable using the
     credentials of the authorising process.

     This allows a process started by /sbin/request-key to read keys belonging
     to the authorising process.

 (5) The magic KEY_SPEC_*_KEYRING key IDs when passed to KEYCTL_INSTANTIATE or
     KEYCTL_NEGATE will specify a keyring of the authorising process, rather
     than the process doing the instantiation.

 (6) One of the process keyrings can be nominated as the default to which
     request_key() should attach new keys if not otherwise specified. This is
     done with KEYCTL_SET_REQKEY_KEYRING and one of the KEY_REQKEY_DEFL_*
     constants. The current setting can also be read using this call.

 (7) request_key() is partially interruptible. If it is waiting for another
     process to finish constructing a key, it can be interrupted. This permits
     a request-key cycle to be broken without recourse to rebooting.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-Off-By: Benoit Boissinot <benoit.boissinot@ens-lyon.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 00:05:19 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00