29 Apr, 2008

2 commits

  • Since these two source files invoke kmalloc(), they should explicitly
    include .

    Signed-off-by: Robert P. J. Day
    Cc: David Howells
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Robert P. J. Day
     
  • Allow the callout data to be passed as a blob rather than a string for
    internal kernel services that call any request_key_*() interface other than
    request_key(). request_key() itself still takes a NUL-terminated string.

    The functions that change are:

    request_key_with_auxdata()
    request_key_async()
    request_key_async_with_auxdata()

    Signed-off-by: David Howells
    Cc: Paul Moore
    Cc: Chris Wright
    Cc: Stephen Smalley
    Cc: James Morris
    Cc: Kevin Coffman
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

08 Feb, 2008

1 commit


17 Oct, 2007

1 commit

  • Make request_key() and co fundamentally asynchronous to make it easier for
    NFS to make use of them. There are now accessor functions that do
    asynchronous constructions, a wait function to wait for construction to
    complete, and a completion function for the key type to indicate completion
    of construction.

    Note that the construction queue is now gone. Instead, keys under
    construction are linked in to the appropriate keyring in advance, and that
    anyone encountering one must wait for it to be complete before they can use
    it. This is done automatically for userspace.

    The following auxiliary changes are also made:

    (1) Key type implementation stuff is split from linux/key.h into
    linux/key-type.h.

    (2) AF_RXRPC provides a way to allocate null rxrpc-type keys so that AFS does
    not need to call key_instantiate_and_link() directly.

    (3) Adjust the debugging macros so that they're -Wformat checked even if
    they are disabled, and make it so they can be enabled simply by defining
    __KDEBUG to be consistent with other code of mine.

    (3) Documentation.

    [alan@lxorguk.ukuu.org.uk: keys: missing word in documentation]
    Signed-off-by: David Howells
    Signed-off-by: Alan Cox
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

18 Jul, 2007

1 commit

  • Rather than using a tri-state integer for the wait flag in
    call_usermodehelper_exec, define a proper enum, and use that. I've
    preserved the integer values so that any callers I've missed should
    still work OK.

    Signed-off-by: Jeremy Fitzhardinge
    Cc: James Bottomley
    Cc: Randy Dunlap
    Cc: Christoph Hellwig
    Cc: Andi Kleen
    Cc: Paul Mackerras
    Cc: Johannes Berg
    Cc: Ralf Baechle
    Cc: Bjorn Helgaas
    Cc: Joel Becker
    Cc: Tony Luck
    Cc: Kay Sievers
    Cc: Srivatsa Vaddagiri
    Cc: Oleg Nesterov
    Cc: David Howells

    Jeremy Fitzhardinge
     

30 Jun, 2006

1 commit

  • The proposed NFS key type uses its own method of passing key requests to
    userspace (upcalling) rather than invoking /sbin/request-key. This is
    because the responsible userspace daemon should already be running and will
    be contacted through rpc_pipefs.

    This patch permits the NFS filesystem to pass auxiliary data to the upcall
    operation (struct key_type::request_key) so that the upcaller can use a
    pre-existing communications channel more easily.

    Signed-off-by: David Howells
    Acked-By: Kevin Coffman
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

27 Jun, 2006

1 commit

  • Add the ability for key creation to overrun the user's quota in some
    circumstances - notably when a session keyring is created and assigned to a
    process that didn't previously have one.

    This means it's still possible to log in, should PAM require the creation of a
    new session keyring, and fix an overburdened key quota.

    Signed-off-by: David Howells
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

23 Jun, 2006

1 commit

  • Introduce SELinux hooks to support the access key retention subsystem
    within the kernel. Incorporate new flask headers from a modified version
    of the SELinux reference policy, with support for the new security class
    representing retained keys. Extend the "key_alloc" security hook with a
    task parameter representing the intended ownership context for the key
    being allocated. Attach security information to root's default keyrings
    within the SELinux initialization routine.

    Has passed David's testsuite.

    Signed-off-by: Michael LeMay
    Signed-off-by: David Howells
    Signed-off-by: James Morris
    Acked-by: Chris Wright
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Michael LeMay
     

09 Jan, 2006

1 commit

  • 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:

    Build fix.

    Signed-off-by: David Howells
    Cc: Trond Myklebust
    Cc: Alexander Zangerl
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

09 Oct, 2005

1 commit


29 Sep, 2005

1 commit

  • The attached patch adds extra permission grants to keys for the possessor of a
    key in addition to the owner, group and other permissions bits. This makes
    SUID binaries easier to support without going as far as labelling keys and key
    targets using the LSM facilities.

    This patch adds a second "pointer type" to key structures (struct key_ref *)
    that can have the bottom bit of the address set to indicate the possession of
    a key. This is propagated through searches from the keyring to the discovered
    key. It has been made a separate type so that the compiler can spot attempts
    to dereference a potentially incorrect pointer.

    The "possession" attribute can't be attached to a key structure directly as
    it's not an intrinsic property of a key.

    Pointers to keys have been replaced with struct key_ref *'s wherever
    possession information needs to be passed through.

    This does assume that the bottom bit of the pointer will always be zero on
    return from kmem_cache_alloc().

    The key reference type has been made into a typedef so that at least it can be
    located in the sources, even though it's basically a pointer to an undefined
    type. I've also renamed the accessor functions to be more useful, and all
    reference variables should now end in "_ref".

    Signed-Off-By: David Howells
    Signed-off-by: Linus Torvalds

    David Howells
     

04 Aug, 2005

1 commit

  • This fixes five bugs in the key management syscall interface:

    (1) add_key() returns 0 rather than EINVAL if the key type is "".

    Checking the key type isn't "" should be left to lookup_user_key().

    (2) request_key() returns ENOKEY rather than EPERM if the key type begins
    with a ".".

    lookup_user_key() can't do this because internal key types begin with a
    ".".

    (3) Key revocation always returns 0, even if it fails.

    (4) Key read can return EAGAIN rather than EACCES under some circumstances.

    A key is permitted to by read by a process if it doesn't grant read
    access, but it does grant search access and it is in the process's
    keyrings. That search returns EAGAIN if it fails, and this needs
    translating to EACCES.

    (5) request_key() never adds the new key to the destination keyring if one is
    supplied.

    The wrong macro was being used to test for an error condition: PTR_ERR()
    will always return true, whether or not there's an error; this should've
    been IS_ERR().

    Signed-Off-By: David Howells
    Signed-Off-By: Linus Torvalds

    David Howells
     

24 Jun, 2005

4 commits

  • 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
    Signed-Off-By: Benoit Boissinot
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     
  • The attached patch uses RCU to manage the session keyring pointer in struct
    signal_struct. This means that searching need not disable interrupts and get
    a the sighand spinlock to access this pointer. Furthermore, by judicious use
    of rcu_read_(un)lock(), this patch also avoids the need to take and put
    refcounts on the session keyring itself, thus saving on even more atomic ops.

    Signed-Off-By: David Howells
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     
  • The attached patch makes it possible to pass a session keyring through to the
    process spawned by call_usermodehelper(). This allows patch 3/3 to pass an
    authorisation key through to /sbin/request-key, thus permitting better access
    controls when doing just-in-time key creation.

    Signed-Off-By: David Howells
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     
  • The attached patch changes the key implementation in a number of ways:

    (1) It removes the spinlock from the key structure.

    (2) The key flags are now accessed using atomic bitops instead of
    write-locking the key spinlock and using C bitwise operators.

    The three instantiation flags are dealt with with the construction
    semaphore held during the request_key/instantiate/negate sequence, thus
    rendering the spinlock superfluous.

    The key flags are also now bit numbers not bit masks.

    (3) The key payload is now accessed using RCU. This permits the recursive
    keyring search algorithm to be simplified greatly since no locks need be
    taken other than the usual RCU preemption disablement. Searching now does
    not require any locks or semaphores to be held; merely that the starting
    keyring be pinned.

    (4) The keyring payload now includes an RCU head so that it can be disposed
    of by call_rcu(). This requires that the payload be copied on unlink to
    prevent introducing races in copy-down vs search-up.

    (5) The user key payload is now a structure with the data following it. It
    includes an RCU head like the keyring payload and for the same reason. It
    also contains a data length because the data length in the key may be
    changed on another CPU whilst an RCU protected read is in progress on the
    payload. This would then see the supposed RCU payload and the on-key data
    length getting out of sync.

    I'm tempted to drop the key's datalen entirely, except that it's used in
    conjunction with quota management and so is a little tricky to get rid
    of.

    (6) Update the keys documentation.

    Signed-Off-By: David Howells
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

17 Apr, 2005

1 commit

  • 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!

    Linus Torvalds