31 Oct, 2005

2 commits

  • The attached patch adds LSM hooks for key management facilities. The notable
    changes are:

    (1) The key struct now supports a security pointer for the use of security
    modules. This will permit key labelling and restrictions on which
    programs may access a key.

    (2) Security modules get a chance to note (or abort) the allocation of a key.

    (3) The key permission checking can now be enhanced by the security modules;
    the permissions check consults LSM if all other checks bear out.

    (4) The key permissions checking functions now return an error code rather
    than a boolean value.

    (5) An extra permission has been added to govern the modification of
    attributes (UID, GID, permissions).

    Note that there isn't an LSM hook specifically for each keyctl() operation,
    but rather the permissions hook allows control of individual operations based
    on the permission request bits.

    Key management access control through LSM is enabled by automatically if both
    CONFIG_KEYS and CONFIG_SECURITY are enabled.

    This should be applied on top of the patch ensubjected:

    [PATCH] Keys: Possessor permissions should be additive

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

    David Howells
     
  • This patch allows SELinux to canonicalize the value returned from
    getxattr() via the security_inode_getsecurity() hook, which is called after
    the fs level getxattr() function.

    The purpose of this is to allow the in-core security context for an inode
    to override the on-disk value. This could happen in cases such as
    upgrading a system to a different labeling form (e.g. standard SELinux to
    MLS) without needing to do a full relabel of the filesystem.

    In such cases, we want getxattr() to return the canonical security context
    that the kernel is using rather than what is stored on disk.

    The implementation hooks into the inode_getsecurity(), adding another
    parameter to indicate the result of the preceding fs-level getxattr() call,
    so that SELinux knows whether to compare a value obtained from disk with
    the kernel value.

    We also now allow getxattr() to work for mountpoint labeled filesystems
    (i.e. mount with option context=foo_t), as we are able to return the
    kernel value to the user.

    Signed-off-by: James Morris
    Signed-off-by: Stephen Smalley
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    James Morris
     

28 Oct, 2005

1 commit


10 Sep, 2005

3 commits

  • This patch removes the inode_post_link and inode_post_rename LSM hooks as
    they are unused (and likely useless).

    Signed-off-by: Stephen Smalley
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Stephen Smalley
     
  • This patch removes the inode_post_create/mkdir/mknod/symlink LSM hooks as
    they are obsoleted by the new inode_init_security hook that enables atomic
    inode security labeling.

    If anyone sees any reason to retain these hooks, please speak now. Also,
    is anyone using the post_rename/link hooks; if not, those could also be
    removed.

    Signed-off-by: Stephen Smalley
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Stephen Smalley
     
  • The following patch set enables atomic security labeling of newly created
    inodes by altering the fs code to invoke a new LSM hook to obtain the security
    attribute to apply to a newly created inode and to set up the incore inode
    security state during the inode creation transaction. This parallels the
    existing processing for setting ACLs on newly created inodes. Otherwise, it
    is possible for new inodes to be accessed by another thread via the dcache
    prior to complete security setup (presently handled by the
    post_create/mkdir/... LSM hooks in the VFS) and a newly created inode may be
    left unlabeled on the disk in the event of a crash. SELinux presently works
    around the issue by ensuring that the incore inode security label is
    initialized to a special SID that is inaccessible to unprivileged processes
    (in accordance with policy), thereby preventing inappropriate access but
    potentially causing false denials on legitimate accesses. A simple test
    program demonstrates such false denials on SELinux, and the patch solves the
    problem. Similar such false denials have been encountered in real
    applications.

    This patch defines a new inode_init_security LSM hook to obtain the security
    attribute to apply to a newly created inode and to set up the incore inode
    security state for it, and adds a corresponding hook function implementation
    to SELinux.

    Signed-off-by: Stephen Smalley
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Stephen Smalley
     

24 Jun, 2005

1 commit

  • Add a new `suid_dumpable' sysctl:

    This value can be used to query and set the core dump mode for setuid
    or otherwise protected/tainted binaries. The modes are

    0 - (default) - traditional behaviour. Any process which has changed
    privilege levels or is execute only will not be dumped

    1 - (debug) - all processes dump core when possible. The core dump is
    owned by the current user and no security is applied. This is intended
    for system debugging situations only. Ptrace is unchecked.

    2 - (suidsafe) - any binary which normally would not be dumped is dumped
    readable by root only. This allows the end user to remove such a dump but
    not access it directly. For security reasons core dumps in this mode will
    not overwrite one another or other files. This mode is appropriate when
    adminstrators are attempting to debug problems in a normal environment.

    (akpm:

    > > +EXPORT_SYMBOL(suid_dumpable);
    >
    > EXPORT_SYMBOL_GPL?

    No problem to me.

    > > if (current->euid == current->uid && current->egid == current->gid)
    > > current->mm->dumpable = 1;
    >
    > Should this be SUID_DUMP_USER?

    Actually the feedback I had from last time was that the SUID_ defines
    should go because its clearer to follow the numbers. They can go
    everywhere (and there are lots of places where dumpable is tested/used
    as a bool in untouched code)

    > Maybe this should be renamed to `dump_policy' or something. Doing that
    > would help us catch any code which isn't using the #defines, too.

    Fair comment. The patch was designed to be easy to maintain for Red Hat
    rather than for merging. Changing that field would create a gigantic
    diff because it is used all over the place.

    )

    Signed-off-by: Alan Cox
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alan Cox
     

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