After shrinking the common_audit_data stack usage for private LSM data I'm
not going to shrink the data union.  To do this I'm going to move anything
larger than 2 void * ptrs to it's own structure and require it to be declared
separately on the calling stack.  Thus hot paths which don't need more than
a couple pointer don't have to declare space to hold large unneeded
structures.  I could get this down to one void * by dealing with the key
struct and the struct path.  We'll see if that is helpful after taking care of
networking.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Linus found that the gigantic size of the common audit data caused a big
perf hit on something as simple as running stat() in a loop.  This patch
requires LSMs to declare the LSM specific portion separately rather than
doing it in a union.  Thus each LSM can be responsible for shrinking their
portion and don't have to pay a penalty just because other LSMs have a
bigger space requirement.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Allow query access as a normal user removing the need
for CAP_MAC_ADMIN. Give RW access to /smack/access
for UGO. Do not import smack labels in access check.

Signed-off-by: Jarkko Sakkinen <jarkko.j.sakkinen@gmail.com>
Signed-off-by: Casey Schaufler <cschaufler@cschaufler-intel.(none)>

There are a number of comments in the Smack code that
are either malformed or include code. This patch cleans
them up.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

This patch is targeted for the smack-next tree.

Smack access checks suffer from two significant performance
issues. In cases where there are large numbers of rules the
search of the single list of rules is wasteful. Comparing the
string values of the smack labels is less efficient than a
numeric comparison would.

These changes take advantage of the Smack label list, which
maintains the mapping of Smack labels to secids and optional
CIPSO labels. Because the labels are kept perpetually, an
access check can be done strictly based on the address of the
label in the list without ever looking at the label itself.
Rather than keeping one global list of rules the rules with
a particular subject label can be based off of that label
list entry. The access check need never look at entries that
do not use the current subject label.

This requires that packets coming off the network with
CIPSO direct Smack labels that have never been seen before
be treated carefully. The only case where they could be
delivered is where the receiving socket has an IPIN star
label, so that case is explicitly addressed.

On a system with 39,800 rules (200 labels in all permutations)
a system with this patch runs an access speed test in 5% of
the time of the old version. That should be a best case
improvement. If all of the rules are associated with the
same subject label and all of the accesses are for processes
with that label (unlikely) the improvement is about 30%.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

This patch separates and audit message that only contains a dentry from
one that contains a full path.  This allows us to make it harder to
misuse the interfaces or for the interfaces to be implemented wrong.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>

The lsm common audit code has wacky contortions making sure which pieces
of information are set based on if it was given a path, dentry, or
inode.  Split this into path and inode to get rid of some of the code
complexity.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>

Kill unused macros of SMACK_LIST_MAX, MAY_ANY and MAY_ANYWRITE.
v2: As Casey Schaufler's advice, also remove MAY_ANY.

Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

  In the embedded world there are often situations
  where libraries are updated from a variety of sources,
  for a variety of reasons, and with any number of
  security characteristics. These differences
  might include privilege required for a given library
  provided interface to function properly, as occurs
  from time to time in graphics libraries. There are
  also cases where it is important to limit use of
  libraries based on the provider of the library and
  the security aware application may make choices
  based on that criteria.

  These issues are addressed by providing an additional
  Smack label that may optionally be assigned to an object,
  the SMACK64MMAP attribute. An mmap operation is allowed
  if there is no such attribute.

  If there is a SMACK64MMAP attribute the mmap is permitted
  only if a subject with that label has all of the access
  permitted a subject with the current task label.

  Security aware applications may from time to time
  wish to reduce their "privilege" to avoid accidental use
  of privilege. One case where this arises is the
  environment in which multiple sources provide libraries
  to perform the same functions. An application may know
  that it should eschew services made available from a
  particular vendor, or of a particular version.

  In support of this a secondary list of Smack rules has
  been added that is local to the task. This list is
  consulted only in the case where the global list has
  approved access. It can only further restrict access.
  Unlike the global last, if no entry is found on the
  local list access is granted. An application can add
  entries to its own list by writing to /smack/load-self.

  The changes appear large as they involve refactoring
  the list handling to accomodate there being more
  than one rule list.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

In a situation where Smack access rules allow processes
with multiple labels to write to a directory it is easy
to get into a situation where the directory gets cluttered
with files that the owner can't deal with because while
they could be written to the directory a process at the
label of the directory can't write them. This is generally
the desired behavior, but when it isn't it is a real
issue.

This patch introduces a new attribute SMACK64TRANSMUTE that
instructs Smack to create the file with the label of the directory
under certain circumstances.

A new access mode, "t" for transmute, is made available to
Smack access rules, which are expanded from "rwxa" to "rwxat".
If a file is created in a directory marked as transmutable
and if access was granted to perform the operation by a rule
that included the transmute mode, then the file gets the
Smack label of the directory instead of the Smack label of the
creating process.

Note that this is equivalent to creating an empty file at the
label of the directory and then having the other process write
to it. The transmute scheme requires that both the access rule
allows transmutation and that the directory be explicitly marked.

Signed-off-by: Jarkko Sakkinen <ext-jarkko.2.sakkinen@nokia.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>