linux-toradex.git/security/integrity, branch v3.0.79

ima: fix invalid memory reference

2012-01-26T01:24:41+00:00

commit 7b7e5916aa2f46e57f8bd8cb89c34620ebfda5da upstream.

Don't free a valid measurement entry on TPM PCR extend failure.

Signed-off-by: Roberto Sassu 
Signed-off-by: Mimi Zohar 
Signed-off-by: Greg Kroah-Hartman

ima: free duplicate measurement memory

2012-01-26T01:24:41+00:00

commit 45fae7493970d7c45626ccd96d4a74f5f1eea5a9 upstream.

Info about new measurements are cached in the iint for performance.  When
the inode is flushed from cache, the associated iint is flushed as well.
Subsequent access to the inode will cause the inode to be re-measured and
will attempt to add a duplicate entry to the measurement list.

This patch frees the duplicate measurement memory, fixing a memory leak.

Signed-off-by: Roberto Sassu 
Signed-off-by: Mimi Zohar 
Signed-off-by: Greg Kroah-Hartman

ima: remove unnecessary call to ima_must_measure

2011-02-23T21:38:52+00:00

The original ima_must_measure() function based its results on cached
iint information, which required an iint be allocated for all files.
Currently, an iint is allocated only for files in policy.  As a result,
for those files in policy, ima_must_measure() is now called twice: once
to determine if the inode is in the measurement policy and, the second
time, to determine if it needs to be measured/re-measured.

The second call to ima_must_measure() unnecessarily checks to see if
the file is in policy. As we already know the file is in policy, this
patch removes the second unnecessary call to ima_must_measure(), removes
the vestige iint parameter, and just checks the iint directly to determine
if the inode has been measured or needs to be measured/re-measured.

Signed-off-by: Mimi Zohar 
Acked-by: Eric Paris

IMA: remove IMA imbalance checking

2011-02-10T12:51:44+00:00

Now that i_readcount is maintained by the VFS layer, remove the
imbalance checking in IMA. Cleans up the IMA code nicely.

Signed-off-by: Mimi Zohar 
Acked-by: Eric Paris

IMA: maintain i_readcount in the VFS layer

2011-02-10T12:51:44+00:00

ima_counts_get() updated the readcount and invalidated the PCR,
as necessary. Only update the i_readcount in the VFS layer.
Move the PCR invalidation checks to ima_file_check(), where it
belongs.

Maintaining the i_readcount in the VFS layer, will allow other
subsystems to use i_readcount.

Signed-off-by: Mimi Zohar 
Acked-by: Eric Paris

IMA: convert i_readcount to atomic

2011-02-10T12:51:43+00:00

Convert the inode's i_readcount from an unsigned int to atomic.

Signed-off-by: Mimi Zohar 
Acked-by: Eric Paris

ima: fix add LSM rule bug

2011-01-04T00:36:33+00:00

If security_filter_rule_init() doesn't return a rule, then not everything
is as fine as the return code implies.

This bug only occurs when the LSM (eg. SELinux) is disabled at runtime.

Adding an empty LSM rule causes ima_match_rules() to always succeed,
ignoring any remaining rules.

 default IMA TCB policy:
  # PROC_SUPER_MAGIC
  dont_measure fsmagic=0x9fa0
  # SYSFS_MAGIC
  dont_measure fsmagic=0x62656572
  # DEBUGFS_MAGIC
  dont_measure fsmagic=0x64626720
  # TMPFS_MAGIC
  dont_measure fsmagic=0x01021994
  # SECURITYFS_MAGIC
  dont_measure fsmagic=0x73636673

  < LSM specific rule >
  dont_measure obj_type=var_log_t

  measure func=BPRM_CHECK
  measure func=FILE_MMAP mask=MAY_EXEC
  measure func=FILE_CHECK mask=MAY_READ uid=0

Thus without the patch, with the boot parameters 'tcb selinux=0', adding
the above 'dont_measure obj_type=var_log_t' rule to the default IMA TCB
measurement policy, would result in nothing being measured.  The patch
prevents the default TCB policy from being replaced.

Signed-off-by: Mimi Zohar 
Cc: James Morris 
Acked-by: Serge Hallyn 
Cc: David Safford 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

IMA: fix the ToMToU logic

2010-10-26T18:37:19+00:00

Current logic looks like this:

        rc = ima_must_measure(NULL, inode, MAY_READ, FILE_CHECK);
        if (rc < 0)
                goto out;

        if (mode & FMODE_WRITE) {
                if (inode->i_readcount)
                        send_tomtou = true;
                goto out;
        }

        if (atomic_read(&inode->i_writecount) > 0)
                send_writers = true;

Lets assume we have a policy which states that all files opened for read
by root must be measured.

Lets assume the file has permissions 777.

Lets assume that root has the given file open for read.

Lets assume that a non-root process opens the file write.

The non-root process will get to ima_counts_get() and will check the
ima_must_measure().  Since it is not supposed to measure it will goto
out.

We should check the i_readcount no matter what since we might be causing
a ToMToU voilation!

This is close to correct, but still not quite perfect.  The situation
could have been that root, which was interested in the mesurement opened
and closed the file and another process which is not interested in the
measurement is the one holding the i_readcount ATM.  This is just overly
strict on ToMToU violations, which is better than not strict enough...

Signed-off-by: Eric Paris 
Acked-by: Mimi Zohar 
Signed-off-by: Linus Torvalds

IMA: explicit IMA i_flag to remove global lock on inode_delete

2010-10-26T18:37:19+00:00

Currently for every removed inode IMA must take a global lock and search
the IMA rbtree looking for an associated integrity structure.  Instead
we explicitly mark an inode when we add an integrity structure so we
only have to take the global lock and do the removal if it exists.

Signed-off-by: Eric Paris 
Acked-by: Mimi Zohar 
Signed-off-by: Linus Torvalds

IMA: drop refcnt from ima_iint_cache since it isn't needed

2010-10-26T18:37:19+00:00

Since finding a struct ima_iint_cache requires a valid struct inode, and
the struct ima_iint_cache is supposed to have the same lifetime as a
struct inode (technically they die together but don't need to be created
at the same time) we don't have to worry about the ima_iint_cache
outliving or dieing before the inode.  So the refcnt isn't useful.  Just
get rid of it and free the structure when the inode is freed.

Signed-off-by: Eric Paris 
Acked-by: Mimi Zohar 
Signed-off-by: Linus Torvalds