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 <zohar@us.ibm.com>
Cc: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Cc: David Safford <safford@watson.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert all of the places IMA calls audit_log_format with %s into
audit_log_untrusted_string(). This is going to cause them all to get
quoted, but it should make audit log injection harder.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
IMA policy load parser will reject any policies with a comment. This patch
will allow the parser to just ignore lines which start with a #. This is not
very robust. # can ONLY be used at the very beginning of a line. Inline
comments are not allowed.
Signed-off-by: Eric Paris
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
IMA parser will fail if whitespace is used in any way other than a single
space. Using a tab or even using 2 spaces in a row will result in a policy
being rejected. This patch makes the kernel ignore whitespace a bit better.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Currently the ima policy load code will print what it doesn't understand
but really I think it should reject any policy it doesn't understand. This
patch makes it so!
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
ima_parse_rule currently sets entry->action = -1 and then later tests
if (entry->action == UNKNOWN). It is true that UNKNOWN == -1 but actually
setting it to UNKNOWN makes a lot more sense in case things change in the
future.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
IMA will accept rules which specify things twice and will only pay
attention to the last one. We should reject such rules.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Currently IMA will only accept one rule per write(). This patch allows IMA to
accept writes which contain multiple rules but only processes one rule per
write. \n is used as the delimiter between rules. IMA will return a short
write indicating that it only accepted up to the first \n.
This allows simple userspace utilities like cat to be used to load an IMA
policy instead of needing a special userspace utility that understood 'one
write per rule'
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
With the movement of the ima hooks functions were renamed from *path* to
*file* since they always deal with struct file. This patch renames some of
the ima internal flags to make them consistent with the rest of the code.
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
A number of IMA functions only used during init are not marked with __init.
Add those notations so they are freed automatically.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
The IMA TCB policy is dangerous. A normal use can use all of a system's
memory (which cannot be freed) simply by building and running lots of
executables. The TCB policy is also nearly useless because logging in as root
often causes a policy violation when dealing with utmp, thus rendering the
measurements meaningless.
There is no good fix for this in the kernel. A full TCB policy would need to
be loaded in userspace using LSM rule matching to get both a protected and
useful system. But, if too little is measured before userspace can load a real
policy one again ends up with a meaningless set of measurements. One option
would be to put the policy load inside the initrd in order to get it early
enough in the boot sequence to be useful, but this runs into trouble with the
LSM. For IMA to measure the LSM policy and the LSM policy loading mechanism
it needs rules to do so, but we already talked about problems with defaulting
to such broad rules....
IMA also depends on the files being measured to be on an FS which implements
and supports i_version. Since the only FS with this support (ext4) doesn't
even use it by default it seems silly to have any IMA rules by default.
This should reduce the performance overhead of IMA to near 0 while still
letting users who choose to configure their machine as such to inclue the
ima_tcb kernel paramenter and get measurements during boot before they can
load a customized, reasonable policy in userspace.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
The selinuxfs superblock magic is used inside the IMA code, but is being
defined in two places and could someday get out of sync. This patch moves the
declaration into magic.h so it is only done once.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
The IMA default policy measures every single file opened by root. This is
terrible for most users. Consider a system (like mine) with virtual machine
images. When those images are touched (which happens at boot for me) those
images are measured. This is just way too much for the default case.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
An audit subsystem change replaced AUDIT_EQUAL with Audit_equal.
Update calls to security_filter_rule_init()/match() to reflect
the change.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Based on discussions on linux-audit, as per Steve Grubb's request
http://lkml.org/lkml/2009/2/6/269, the following changes were made:
- forced audit result to be either 0 or 1.
- made template names const
- Added new stand-alone message type: AUDIT_INTEGRITY_RULE
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Support for a user loadable policy through securityfs
with support for LSM specific policy data.
- free invalid rule in ima_parse_add_rule()
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
IMA provides hardware (TPM) based measurement and attestation for
file measurements. As the Trusted Computing (TPM) model requires,
IMA measures all files before they are accessed in any way (on the
integrity_bprm_check, integrity_path_check and integrity_file_mmap
hooks), and commits the measurements to the TPM. Once added to the
TPM, measurements can not be removed.
In addition, IMA maintains a list of these file measurements, which
can be used to validate the aggregate value stored in the TPM. The
TPM can sign these measurements, and thus the system can prove, to
itself and to a third party, the system's integrity in a way that
cannot be circumvented by malicious or compromised software.
- alloc ima_template_entry before calling ima_store_template()
- log ima_add_boot_aggregate() failure
- removed unused IMA_TEMPLATE_NAME_LEN
- replaced hard coded string length with #define name
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
