In preparation of supporting more hash algorithms with larger hash sizes
needed for signature verification, this patch replaces the 20 byte sized
digest, with a more flexible structure.  The new structure includes the
hash algorithm, digest size, and digest.

Changelog:
- recalculate filedata hash for the measurement list, if the signature
  hash digest size is greater than 20 bytes.
- use generic HASH_ALGO_
- make ima_calc_file_hash static
- scripts lindent and checkpatch fixes
Signed-off-by: NDmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Fix checkpatch, lindent, etc, warnings/errors
Signed-off-by: NDmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Replace a bunch of file->dentry->d_inode refs with file_inode().

In __fput(), use file->f_inode instead so as not to be affected by any tricks
that file_inode() might grow.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Passing a pointer to the dentry name, as a parameter to
process_measurement(), causes a race condition with rename() and
is unnecessary, as the dentry name is already accessible via the
file parameter.

In the normal case, we use the full pathname as provided by
brpm->filename, bprm->interp, or ima_d_path().  Only on ima_d_path()
failure, do we fallback to using the d_name.name, which points
either to external memory or d_iname.
Reported-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

Commit "750943a3 ima: remove enforce checking duplication" combined
the 'in IMA policy' and 'enforcing file integrity' checks.  For
the non-file, kernel module verification, a specific check for
'enforcing file integrity' was not added.  This patch adds the
check.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Different hooks can require different methods for appraising a
file's integrity.  As a result, an integrity appraisal status is
cached on a per hook basis.

Only a hook specific rule, requires the inode to be re-appraised.
This patch eliminates unnecessary appraisals.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>

With the new IMA policy 'appraise_type=' option, different hooks
can require different methods for appraising a file's integrity.

For example, the existing 'ima_appraise_tcb' policy defines a
generic rule, requiring all root files to be appraised, without
specfying the appraisal method.  A more specific rule could require
all kernel modules, for example, to be signed.

appraise fowner=0 func=MODULE_CHECK appraise_type=imasig
appraise fowner=0

As a result, the integrity appraisal results for the same inode, but
for different hooks, could differ.  This patch caches the integrity
appraisal results on a per hook basis.

Changelog v2:
- Rename ima_cache_status() to ima_set_cache_status()
- Rename and move get_appraise_status() to ima_get_cache_status()
Changelog v0:
- include IMA_APPRAISE/APPRAISED_SUBMASK in IMA_DO/DONE_MASK (Dmitry)
- Support independent MODULE_CHECK appraise status.
- fixed IMA_XXXX_APPRAISE/APPRAISED flags
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>

The 'security.ima' extended attribute may contain either the file data's
hash or a digital signature.  This patch adds support for requiring a
specific extended attribute type.  It extends the IMA policy with a new
keyword 'appraise_type=imasig'.  (Default is hash.)

Changelog v2:
- Fixed Documentation/ABI/testing/ima_policy option syntax
Changelog v1:
- Differentiate between 'required' vs. 'actual' extended attribute
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

This patch forbids write access to files with digital signatures, as they
are considered immutable.
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Define a new function ima_d_path(), which returns the full pathname.
This function will be used further, for example, by the directory
verification code.
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Rename FILE_MMAP hook to MMAP_CHECK to be consistent with the other
hook names.
Signed-off-by: NMimi Zohar <zohar@us.ibm.com>

Based on the IMA appraisal policy, files are appraised.  For those
files appraised, the IMA hooks return the integrity appraisal result,
assuming IMA-appraisal is in enforcing mode.  This patch combines
both of these criteria (in policy and enforcing file integrity),
removing the checking duplication.

Changelog v1:
- Update hook comments
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

The new kernel module syscall appraises kernel modules based
on policy.   If the IMA policy requires kernel module checking,
fallback to module signature enforcing for the existing syscall.
Without CONFIG_MODULE_SIG_FORCE enabled, the kernel module's
integrity is unknown, return -EACCES.

Changelog v1:
- Fix ima_module_check() return result (Tetsuo Handa)
Reported-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NMimi Zohar <zohar@us.ibm.com>

With the addition of the new kernel module syscall, which defines two
arguments - a file descriptor to the kernel module and a pointer to a NULL
terminated string of module arguments - it is now possible to measure and
appraise kernel modules like any other file on the file system.

This patch adds support to measure and appraise kernel modules in an
extensible and consistent manner.

To support filesystems without extended attribute support, additional
patches could pass the signature as the first parameter.
Signed-off-by: NMimi Zohar <zohar@us.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This adds an 'audit' policy action which audit logs file measurements.

Changelog v6:
 - use new action flag handling (Dmitry Kasatkin).
 - removed whitespace (Mimi)

Changelog v5:
 - use audit_log_untrustedstring.

Changelog v4:
 - cleanup digest -> hash conversion.
 - use filename rather than d_path in ima_audit_measurement.

Changelog v3:
 - Use newly exported audit_log_task_info for logging pid/ppid/uid/etc.
 - Update the ima_policy ABI documentation.

Changelog v2:
 - Use 'audit' action rather than 'measure_and_audit' to permit
 auditing in the absence of measuring..

Changelog v1:
 - Initial posting.
Signed-off-by: NPeter Moody <pmoody@google.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Make the IMA action flag handling generic in order to support
additional new actions, without requiring changes to the base
implementation.  New actions, like audit logging, will only
need to modify the define statements.
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

When AUDIT action support is added to the IMA,
ima_must_appraise_or_measure() does not reflect the real meaning anymore.
Rename it to ima_get_action().
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

With IMA-appraisal's removal of the iint mutex and taking the i_mutex
instead, allocating the iint becomes a lot simplier, as we don't need
to be concerned with two processes racing to allocate the iint. This
patch cleans up and improves performance for allocating the iint.

- removed redundant double i_mutex locking
- combined iint allocation with tree search

Changelog v2:
- removed the rwlock/read_lock changes from this patch
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: NMimi Zohar <zohar@us.ibm.com>

IMA currently maintains an integrity measurement list used to assert the
integrity of the running system to a third party.  The IMA-appraisal
extension adds local integrity validation and enforcement of the
measurement against a "good" value stored as an extended attribute
'security.ima'.  The initial methods for validating 'security.ima' are
hashed based, which provides file data integrity, and digital signature
based, which in addition to providing file data integrity, provides
authenticity.

This patch creates and maintains the 'security.ima' xattr, containing
the file data hash measurement.  Protection of the xattr is provided by
EVM, if enabled and configured.

Based on policy, IMA calls evm_verifyxattr() to verify a file's metadata
integrity and, assuming success, compares the file's current hash value
with the one stored as an extended attribute in 'security.ima'.

Changelov v4:
- changed iint cache flags to hex values

Changelog v3:
- change appraisal default for filesystems without xattr support to fail

Changelog v2:
- fix audit msg 'res' value
- removed unused 'ima_appraise=' values

Changelog v1:
- removed unused iint mutex (Dmitry Kasatkin)
- setattr hook must not reset appraised (Dmitry Kasatkin)
- evm_verifyxattr() now differentiates between no 'security.evm' xattr
  (INTEGRITY_NOLABEL) and no EVM 'protected' xattrs included in the
  'security.evm' (INTEGRITY_NOXATTRS).
- replace hash_status with ima_status (Dmitry Kasatkin)
- re-initialize slab element ima_status on free (Dmitry Kasatkin)
- include 'security.ima' in EVM if CONFIG_IMA_APPRAISE, not CONFIG_IMA
- merged half "ima: ima_must_appraise_or_measure API change" (Dmitry Kasatkin)
- removed unnecessary error variable in process_measurement() (Dmitry Kasatkin)
- use ima_inode_post_setattr() stub function, if IMA_APPRAISE not configured
  (moved ima_inode_post_setattr() to ima_appraise.c)
- make sure ima_collect_measurement() can read file

Changelog:
- add 'iint' to evm_verifyxattr() call (Dimitry Kasatkin)
- fix the race condition between chmod, which takes the i_mutex and then
  iint->mutex, and ima_file_free() and process_measurement(), which take
  the locks in the reverse order, by eliminating iint->mutex. (Dmitry Kasatkin)
- cleanup of ima_appraise_measurement() (Dmitry Kasatkin)
- changes as a result of the iint not allocated for all regular files, but
  only for those measured/appraised.
- don't try to appraise new/empty files
- expanded ima_appraisal description in ima/Kconfig
- IMA appraise definitions required even if IMA_APPRAISE not enabled
- add return value to ima_must_appraise() stub
- unconditionally set status = INTEGRITY_PASS *after* testing status,
  not before.  (Found by Joe Perches)
Signed-off-by: NMimi Zohar <zohar@us.ibm.com>
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>

Set ima_initialized only if initialization was successful.
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

IMA cannot be used as module and does not need __exit functions.
Removed them.
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

The IMA measurement list contains filename hints, which can be
ambigious without the full pathname.  This patch replaces the
filename hint with the full pathname, simplifying for userspace
the correlating of file hash measurements with files.

Change log v1:
- Revert to short filenames, when full pathname is longer than IMA
  measurement buffer size. (Based on Dmitry's review)
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

When IMA was first upstreamed, the bprm filename and interp were
always the same.  Currently, the bprm->filename and bprm->interp
are the same, except for when only bprm->interp contains the
interpreter name.  So instead of using the bprm->filename as
the IMA filename hint in the measurement list, we could replace
it with bprm->interp, but this feels too fragil.

The following patch is not much better, but at least there is some
indication that sometimes we're passing the filename and other times
the interpreter name.
Reported-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

Fixes sparse warnings:
security/integrity/ima/ima_main.c:105:6: warning: symbol 'ima_file_free' was not declared. Should it be static?
security/integrity/ima/ima_main.c:167:5: warning: symbol 'ima_file_mmap' was not declared. Should it be static?
security/integrity/ima/ima_main.c:192:5: warning: symbol 'ima_bprm_check' was not declared. Should it be static?
security/integrity/ima/ima_main.c:211:5: warning: symbol 'ima_file_check' was not declared. Should it be static?
Signed-off-by: NJames Morris <jmorris@namei.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Move the inode integrity data(iint) management up to the integrity directory
in order to share the iint among the different integrity models.

Changelog:
- don't define MAX_DIGEST_SIZE
- rename several globally visible 'ima_' prefixed functions, structs,
  locks, etc to 'integrity_'
- replace '20' with SHA1_DIGEST_SIZE
- reflect location change in appropriate Kconfig and Makefiles
- remove unnecessary initialization of iint_initialized to 0
- rebased on current ima_iint.c
- define integrity_iint_store/lock as static

There should be no other functional changes.
Signed-off-by: NMimi Zohar <zohar@us.ibm.com>
Acked-by: NSerge Hallyn <serge.hallyn@ubuntu.com>

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: NMimi Zohar <zohar@us.ibm.com>
Acked-by: NEric Paris <eparis@redhat.com>

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: NMimi Zohar <zohar@us.ibm.com>
Acked-by: NEric Paris <eparis@redhat.com>

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: NMimi Zohar <zohar@us.ibm.com>
Acked-by: NEric Paris <eparis@redhat.com>

Convert the inode's i_readcount from an unsigned int to atomic.
Signed-off-by: NMimi Zohar <zohar@us.ibm.com>
Acked-by: NEric Paris <eparis@redhat.com>

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: NEric Paris <eparis@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEric Paris <eparis@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEric Paris <eapris@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

IMA always allocates an integrity structure to hold information about
every inode, but only needed this structure to track the number of
readers and writers currently accessing a given inode.  Since that
information was moved into struct inode instead of the integrity struct
this patch stops allocating the integrity stucture until it is needed.
Thus greatly reducing memory usage.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

IMA currently allocated an inode integrity structure for every inode in
core.  This stucture is about 120 bytes long.  Most files however
(especially on a system which doesn't make use of IMA) will never need
any of this space.  The problem is that if IMA is enabled we need to
know information about the number of readers and the number of writers
for every inode on the box.  At the moment we collect that information
in the per inode iint structure and waste the rest of the space.  This
patch moves those counters into the struct inode so we can eventually
stop allocating an IMA integrity structure except when absolutely
needed.

This patch does the minimum needed to move the location of the data.
Further cleanups, especially the location of counter updates, may still
be possible.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

IMA tracks the number of struct files which are holding a given inode
readonly and the number which are holding the inode write or r/w.  It
needs this information so when a new reader or writer comes in it can
tell if this new file will be able to invalidate results it already made
about existing files.

aka if a task is holding a struct file open RO, IMA measured the file
and recorded those measurements and then a task opens the file RW IMA
needs to note in the logs that the old measurement may not be correct.
It's called a "Time of Measure Time of Use" (ToMToU) issue.  The same is
true is a RO file is opened to an inode which has an open writer.  We
cannot, with any validity, measure the file in question since it could
be changing.

This patch attempts to use the i_writecount field to track writers.  The
i_writecount field actually embeds more information in it's value than
IMA needs but it should work for our purposes and allow us to shrink the
struct inode even more.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently IMA used the iint->mutex to protect the i_readcount and
i_writecount.  This patch uses the inode->i_lock since we are going to
start using in inode objects and that is the most appropriate lock.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently IMA uses 2 longs in struct inode.  To save space (and as it
seems impossible to overflow 32 bits) we switch these to unsigned int.
The switch to unsigned does require slightly different checks for
underflow, but it isn't complex.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The opencount was used to help debugging to make sure that everything
which created a struct file also correctly made the IMA calls.  Since we
moved all of that into the VFS this isn't as necessary.  We should be
able to get the same amount of debugging out of just the reader and
write count.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>