ima: return an error code from ima_add_boot_aggregate()
This patch modifies ima_add_boot_aggregate() to return an error code.
This way we can determine if all the initialization procedures have
been executed successfully.
Dmitry Kasatkin [Thu, 8 May 2014 10:11:29 +0000 (13:11 +0300)]
ima: provide 'ima_appraise=log' kernel option
The kernel boot parameter "ima_appraise" currently defines 'off',
'enforce' and 'fix' modes. When designing a policy and labeling
the system, access to files are either blocked in the default
'enforce' mode or automatically fixed in the 'fix' mode. It is
beneficial to be able to run the system in a logging only mode,
without fixing it, in order to properly analyze the system. This
patch adds a 'log' mode to run the system in a permissive mode and
log the appraisal results.
Dmitry Kasatkin [Fri, 27 Jun 2014 10:01:32 +0000 (13:01 +0300)]
ima: move keyring initialization to ima_init()
ima_init() is used as a single place for all initializations.
Experimental keyring patches used the 'late_initcall' which was
co-located with the late_initcall(init_ima). When the late_initcall
for the keyring initialization was abandoned, initialization moved
to init_ima, though it would be more logical to move it to ima_init,
where the rest of the initialization is done. This patch moves the
keyring initialization to ima_init() as a preparatory step for
loading the keys which will be added to ima_init() in following
patches.
integrity: make integrity files as 'integrity' module
The kernel print macros use the KBUILD_MODNAME, which is initialized
to the module name. The current integrity/Makefile makes every file
as its own module, so pr_xxx messages are prefixed with the file name
instead of the module. Similar to the evm/Makefile and ima/Makefile,
this patch fixes the integrity/Makefile to use the single name
'integrity'.
integrity: base integrity subsystem kconfig options on integrity
The integrity subsystem has lots of options and takes more than
half of the security menu. This patch consolidates the options
under "integrity", which are hidden if not enabled. This change
does not affect existing configurations. Re-configuration is not
needed.
Changes v4:
- no need to change "integrity subsystem" to menuconfig as
options are hidden, when not enabled. (Mimi)
- add INTEGRITY Kconfig help description
Changes v3:
- dependency to INTEGRITY removed when behind 'if INTEGRITY'
Changes v2:
- previous patch moved integrity out of the 'security' menu.
This version keeps integrity as a security option (Mimi).
Dmitry Kasatkin [Tue, 19 Aug 2014 13:48:39 +0000 (16:48 +0300)]
ima: remove usage of filename parameter
In all cases except ima_bprm_check() the filename was not defined
and ima_d_path() was used to find the full path. Unfortunately,
the bprm filename is a relative pathname (eg. ./<dir>/filename).
ima_bprm_check() selects between bprm->interp and bprm->filename.
The following dump demonstrates the differences between using
filename and interp.
Dmitry Kasatkin [Wed, 20 Aug 2014 09:37:57 +0000 (12:37 +0300)]
ima: remove unnecessary appraisal test
ima_get_action() sets the "action" flags based on policy.
Before collecting, measuring, appraising, or auditing the
file, the "action" flag is updated based on the cached
iint->flags.
This patch removes the subsequent unnecessary appraisal
test in ima_appraise_measurement().
Dmitry Kasatkin [Fri, 22 Aug 2014 06:43:55 +0000 (09:43 +0300)]
ima: simplify conditional statement to improve performance
Precede bit testing before string comparison makes code
faster. Also refactor statement as a single line pointer
assignment. Logic is following: we set 'xattr_ptr' to read
xattr value when we will do appraisal or in any case when
measurement template is other than 'ima'.
Dmitry Kasatkin [Tue, 19 Aug 2014 11:56:18 +0000 (14:56 +0300)]
integrity: remove declaration of non-existing functions
Commit f381c27 "integrity: move ima inode integrity data management"
(re)moved few functions but left their declarations in header files.
This patch removes them and also removes duplicated declaration of
integrity_iint_find().
Commit c7de7ad "ima: remove unused cleanup functions". This patch
removes these definitions as well.
Dmitry Kasatkin [Fri, 27 Jun 2014 15:15:44 +0000 (18:15 +0300)]
ima: pass 'opened' flag to identify newly created files
Empty files and missing xattrs do not guarantee that a file was
just created. This patch passes FILE_CREATED flag to IMA to
reliably identify new files.
evm: properly handle INTEGRITY_NOXATTRS EVM status
Unless an LSM labels a file during d_instantiate(), newly created
files are not labeled with an initial security.evm xattr, until
the file closes. EVM, before allowing a protected, security xattr
to be written, verifies the existing 'security.evm' value is good.
For newly created files without a security.evm label, this
verification prevents writing any protected, security xattrs,
until the file closes.
Following is the example when this happens:
fd = open("foo", O_CREAT | O_WRONLY, 0644);
setxattr("foo", "security.SMACK64", value, sizeof(value), 0);
close(fd);
While INTEGRITY_NOXATTRS status is handled in other places, such
as evm_inode_setattr(), it does not handle it in all cases in
evm_protect_xattr(). By limiting the use of INTEGRITY_NOXATTRS to
newly created files, we can now allow setting "protected" xattrs.
Changelog:
- limit the use of INTEGRITY_NOXATTRS to IMA identified new files
Dmitry Kasatkin [Fri, 27 Jun 2014 15:04:27 +0000 (18:04 +0300)]
ima: provide flag to identify new empty files
On ima_file_free(), newly created empty files are not labeled with
an initial security.ima value, because the iversion did not change.
Commit dff6efc "fs: fix iversion handling" introduced a change in
iversion behavior. To verify this change use the shell command:
This patch defines the IMA_NEW_FILE flag. The flag is initially
set, when IMA detects that a new file is created, and subsequently
checked on the ima_file_free() hook to set the initial security.ima
value.
Dmitry Kasatkin [Mon, 23 Jun 2014 17:32:56 +0000 (20:32 +0300)]
ima: fix fallback to use new_sync_read()
3.16 commit aad4f8bb42af06371aa0e85bf0cd9d52c0494985
'switch simple generic_file_aio_read() users to ->read_iter()'
replaced ->aio_read with ->read_iter in most of the file systems
and introduced new_sync_read() as a replacement for do_sync_read().
Most of file systems set '->read' and ima_kernel_read is not affected.
When ->read is not set, this patch adopts fallback call changes from the
vfs_read.
Dmitry Kasatkin [Fri, 15 Aug 2014 10:28:52 +0000 (13:28 +0300)]
ima: prevent buffer overflow in ima_alloc_tfm()
This patch fixes the case where the file's signature/hash xattr contains
an invalid hash algorithm. Although we can not verify the xattr, we still
need to measure the file. Use the default IMA hash algorithm.
Unlike shash tfm memory, which is allocated on initialization, the
ahash tfm memory allocation is deferred until needed.
This patch fixes the case where ima_ahash_tfm has not yet been
allocated and the file's signature/hash xattr contains an invalid hash
algorithm. Although we can not verify the xattr, we still need to
measure the file. Use the default IMA hash algorithm.
Changelog:
- set valid algo before testing tfm - based on Dmitry's comment
Mark Rustad [Thu, 28 Aug 2014 11:43:09 +0000 (04:43 -0700)]
security: Silence shadow warning
Renaming an unused formal parameter in the static inline function
security_inode_init_security eliminates many W=2 warnings.
Signed-off-by: Mark Rustad <mark.d.rustad@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
Paul Moore [Fri, 1 Aug 2014 15:17:37 +0000 (11:17 -0400)]
netlabel: shorter names for the NetLabel catmap funcs/structs
Historically the NetLabel LSM secattr catmap functions and data
structures have had very long names which makes a mess of the NetLabel
code and anyone who uses NetLabel. This patch renames the catmap
functions and structures from "*_secattr_catmap_*" to just "*_catmap_*"
which improves things greatly.
There are no substantial code or logic changes in this patch.
Signed-off-by: Paul Moore <pmoore@redhat.com> Tested-by: Casey Schaufler <casey@schaufler-ca.com>
Paul Moore [Fri, 1 Aug 2014 15:17:29 +0000 (11:17 -0400)]
netlabel: fix the catmap walking functions
The two NetLabel LSM secattr catmap walk functions didn't handle
certain edge conditions correctly, causing incorrect security labels
to be generated in some cases. This patch corrects these problems and
converts the functions to use the new _netlbl_secattr_catmap_getnode()
function in order to reduce the amount of repeated code.
Cc: stable@vger.kernel.org Signed-off-by: Paul Moore <pmoore@redhat.com> Tested-by: Casey Schaufler <casey@schaufler-ca.com>
Paul Moore [Fri, 1 Aug 2014 15:17:17 +0000 (11:17 -0400)]
netlabel: fix the horribly broken catmap functions
The NetLabel secattr catmap functions, and the SELinux import/export
glue routines, were broken in many horrible ways and the SELinux glue
code fiddled with the NetLabel catmap structures in ways that we
probably shouldn't allow. At some point this "worked", but that was
likely due to a bit of dumb luck and sub-par testing (both inflicted
by yours truly). This patch corrects these problems by basically
gutting the code in favor of something less obtuse and restoring the
NetLabel abstractions in the SELinux catmap glue code.
Everything is working now, and if it decides to break itself in the
future this code will be much easier to debug than the code it
replaces.
One noteworthy side effect of the changes is that it is no longer
necessary to allocate a NetLabel catmap before calling one of the
NetLabel APIs to set a bit in the catmap. NetLabel will automatically
allocate the catmap nodes when needed, resulting in less allocations
when the lowest bit is greater than 255 and less code in the LSMs.
Cc: stable@vger.kernel.org Reported-by: Christian Evans <frodox@zoho.com> Signed-off-by: Paul Moore <pmoore@redhat.com> Tested-by: Casey Schaufler <casey@schaufler-ca.com>
Paul Moore [Fri, 1 Aug 2014 15:17:03 +0000 (11:17 -0400)]
netlabel: fix a problem when setting bits below the previously lowest bit
The NetLabel category (catmap) functions have a problem in that they
assume categories will be set in an increasing manner, e.g. the next
category set will always be larger than the last. Unfortunately, this
is not a valid assumption and could result in problems when attempting
to set categories less than the startbit in the lowest catmap node.
In some cases kernel panics and other nasties can result.
This patch corrects the problem by checking for this and allocating a
new catmap node instance and placing it at the front of the list.
Cc: stable@vger.kernel.org Reported-by: Christian Evans <frodox@zoho.com> Signed-off-by: Paul Moore <pmoore@redhat.com> Tested-by: Casey Schaufler <casey@schaufler-ca.com>
David Howells [Thu, 31 Jul 2014 13:46:44 +0000 (14:46 +0100)]
PKCS#7: X.509 certificate issuer and subject are mandatory fields in the ASN.1
X.509 certificate issuer and subject fields are mandatory fields in the ASN.1
and so their existence needn't be tested for. They are guaranteed to end up
with an empty string if the name material has nothing we can use (see
x509_fabricate_name()).
Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com>
Andy Shevchenko [Wed, 9 Jul 2014 12:34:41 +0000 (15:34 +0300)]
tpm: simplify code by using %*phN specifier
Instead of looping by ourselves we may use %*phN specifier to dump a small
buffer.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
[ PHuewe: removed now unused variable i ] Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Jason Gunthorpe [Thu, 22 May 2014 00:26:44 +0000 (18:26 -0600)]
tpm: Provide a generic means to override the chip returned timeouts
Some Atmel TPMs provide completely wrong timeouts from their
TPM_CAP_PROP_TIS_TIMEOUT query. This patch detects that and returns
new correct values via a DID/VID table in the TIS driver.
Tested on ARM using an AT97SC3204T FW version 37.16
Cc: <stable@vger.kernel.org>
[PHuewe: without this fix these 'broken' Atmel TPMs won't function on
older kernels] Signed-off-by: "Berg, Christopher" <Christopher.Berg@atmel.com> Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Jason Gunthorpe [Sat, 9 Nov 2013 18:17:00 +0000 (11:17 -0700)]
tpm: Add missing tpm_do_selftest to ST33 I2C driver
Most device drivers do call 'tpm_do_selftest' which executes a
TPM_ContinueSelfTest. tpm_i2c_stm_st33 is just pointlessly different,
I think it is bug.
These days we have the general assumption that the TPM is usable by
the kernel immediately after the driver is finished, so we can no
longer defer the mandatory self test to userspace.
Cc: <stable@vger.kernel.org> # 3.12+ Reported-by: Richard Marciel <rmaciel@linux.vnet.ibm.com> Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
David Howells [Mon, 28 Jul 2014 13:11:32 +0000 (14:11 +0100)]
PKCS#7: Use x509_request_asymmetric_key()
pkcs7_request_asymmetric_key() and x509_request_asymmetric_key() do the same
thing, the latter being a copy of the former created by the IMA folks, so drop
the PKCS#7 version as the X.509 location is more general.
Whilst we're at it, rename the arguments of x509_request_asymmetric_key() to
better reflect what the values being passed in are intended to match on an
X.509 cert.
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Unfortunately, the commit in question caused problems with Bluetooth
devices, specifically it caused them to get caught in the newly
created BUG_ON() check. The AF_ALG problem still exists, but will be
addressed in a future patch.
Cc: stable@vger.kernel.org Signed-off-by: Paul Moore <pmoore@redhat.com>
Commit fc7c70e "KEYS: struct key_preparsed_payload should have two
payload pointers" erroneously modified encrypted-keys. This patch
reverts the change to that file.
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: David Howells <dhowells@redhat.com>
ima: add support for measuring and appraising firmware
The "security: introduce kernel_fw_from_file hook" patch defined a
new security hook to evaluate any loaded firmware that wasn't built
into the kernel.
This patch defines ima_fw_from_file(), which is called from the new
security hook, to measure and/or appraise the loaded firmware's
integrity.
Kees Cook [Tue, 25 Feb 2014 21:06:00 +0000 (13:06 -0800)]
firmware_class: perform new LSM checks
This attaches LSM hooks to the existing firmware loading interfaces:
filesystem-found firmware and demand-loaded blobs. On errors, loads
are aborted and the failure code is returned to userspace.
Kees Cook [Tue, 25 Feb 2014 18:28:04 +0000 (10:28 -0800)]
security: introduce kernel_fw_from_file hook
In order to validate the contents of firmware being loaded, there must be
a hook to evaluate any loaded firmware that wasn't built into the kernel
itself. Without this, there is a risk that a root user could load malicious
firmware designed to mount an attack against kernel memory (e.g. via DMA).
We found, when trying to run an application from an application which
had dropped privs that the kernel does security checks on undefined
capability bits. This was ESPECIALLY difficult to debug as those
undefined bits are hidden from /proc/$PID/status.
Consider a root application which drops all capabilities from ALL 4
capability sets. We assume, since the application is going to set
eff/perm/inh from an array that it will clear not only the defined caps
less than CAP_LAST_CAP, but also the higher 28ish bits which are
undefined future capabilities.
The BSET gets cleared differently. Instead it is cleared one bit at a
time. The problem here is that in security/commoncap.c::cap_task_prctl()
we actually check the validity of a capability being read. So any task
which attempts to 'read all things set in bset' followed by 'unset all
things set in bset' will not even attempt to unset the undefined bits
higher than CAP_LAST_CAP.
All of this 'should' be fine. Given that these are undefined bits that
aren't supposed to have anything to do with permissions. But they do...
So lets now consider a task which cleared the eff/perm/inh completely
and cleared all of the valid caps in the bset (but not the invalid caps
it couldn't read out of the kernel). We know that this is exactly what
the libcap-ng library does and what the go capabilities library does.
They both leave you in that above situation if you try to clear all of
you capapabilities from all 4 sets. If that root task calls execve()
the child task will pick up all caps not blocked by the bset. The bset
however does not block bits higher than CAP_LAST_CAP. So now the child
task has bits in eff which are not in the parent. These are
'meaningless' undefined bits, but still bits which the parent doesn't
have.
The problem is now in cred_cap_issubset() (or any operation which does a
subset test) as the child, while a subset for valid cap bits, is not a
subset for invalid cap bits! So now we set durring commit creds that
the child is not dumpable. Given it is 'more priv' than its parent. It
also means the parent cannot ptrace the child and other stupidity.
The solution here:
1) stop hiding capability bits in status
This makes debugging easier!
2) stop giving any task undefined capability bits. it's simple, it you
don't put those invalid bits in CAP_FULL_SET you won't get them in init
and you won't get them in any other task either.
This fixes the cap_issubset() tests and resulting fallout (which
made the init task in a docker container untraceable among other
things)
3) mask out undefined bits when sys_capset() is called as it might use
~0, ~0 to denote 'all capabilities' for backward/forward compatibility.
This lets 'capsh --caps="all=eip" -- -c /bin/bash' run.
4) mask out undefined bit when we read a file capability off of disk as
again likely all bits are set in the xattr for forward/backward
compatibility.
This lets 'setcap all+pe /bin/bash; /bin/bash' run
Signed-off-by: Eric Paris <eparis@redhat.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andrew Vagin <avagin@openvz.org> Cc: Andrew G. Morgan <morgan@kernel.org> Cc: Serge E. Hallyn <serge.hallyn@canonical.com> Cc: Kees Cook <keescook@chromium.org> Cc: Steve Grubb <sgrubb@redhat.com> Cc: Dan Walsh <dwalsh@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: James Morris <james.l.morris@oracle.com>
commoncap: don't alloc the credential unless needed in cap_task_prctl
In function cap_task_prctl(), we would allocate a credential
unconditionally and then check if we support the requested function.
If not we would release this credential with abort_creds() by using
RCU method. But on some archs such as powerpc, the sys_prctl is heavily
used to get/set the floating point exception mode. So the unnecessary
allocating/releasing of credential not only introduce runtime overhead
but also do cause OOM due to the RCU implementation.
This patch removes abort_creds() from cap_task_prctl() by calling
prepare_creds() only when we need to modify it.
Reported-by: Kevin Hao <haokexin@gmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Paul Moore <paul@paul-moore.com> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: James Morris <james.l.morris@oracle.com>
Here's a set of changes that implement a PKCS#7 message parser in the kernel.
The PKCS#7 message parsing will then be used to limit kexec to authenticated
kernels only if so configured.
The changes provide the following facilities:
(1) Parse an ASN.1 PKCS#7 message and pick out useful bits such as the data
content and the X.509 certificates used to sign it and all the data
signatures.
(2) Verify all the data signatures against the set of X.509 certificates
available in the message.
(3) Follow the certificate chains and verify that:
(a) for every self-signed X.509 certificate, check that it validly signed
itself, and:
(b) for every non-self-signed certificate, if we have a 'parent'
certificate, the former is validly signed by the latter.
(4) Look for intersections between the certificate chains and the trusted
keyring, if any intersections are found, verify that the trusted
certificates signed the intersection point in the chain.
(5) For testing purposes, a key type can be made available that will take a
PKCS#7 message, check that the message is trustworthy, and if so, add its
data content into the key.
Note that (5) has to be altered to take account of the preparsing patches
already committed to this branch.
Signed-off-by: David Howells <dhowells@redhat.com>
David Howells [Tue, 22 Jul 2014 20:51:20 +0000 (21:51 +0100)]
Merge tag 'keys-preparse-1-20140722' into keys-next
Here are a set of changes that make all but encrypted and trusted keys use
preparsing. Unfortunately, encrypted and trusted keys incorrectly use the
update op to alter a key, so other changes will need to be made for them.
These changes permit payload parsing when instantiating or updating a key to be
done before locks are taken and to determine the amount of quota that will be
required in advance. The latter will make it possible to do LRU discard before
any locks are taken.
Signed-off-by: David Howells <dhowells@redhat.com>
David Howells [Fri, 18 Jul 2014 17:56:36 +0000 (18:56 +0100)]
KEYS: request_key_auth: Provide key preparsing
Provide key preparsing for the request_key_auth key type so that we can make
preparsing mandatory. This does nothing as this type can only be set up
internally to the kernel.
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Jeff Layton <jlayton@primarydata.com>
David Howells [Fri, 18 Jul 2014 17:56:35 +0000 (18:56 +0100)]
KEYS: Ceph: Use user_match()
Ceph can use user_match() instead of defining its own identical function.
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Reviewed-by: Sage Weil <sage@redhat.com>
cc: Tommi Virtanen <tommi.virtanen@dreamhost.com>
David Howells [Fri, 18 Jul 2014 17:56:35 +0000 (18:56 +0100)]
KEYS: Ceph: Use key preparsing
Make use of key preparsing in Ceph so that quota size determination can take
place prior to keyring locking when a key is being added.
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Reviewed-by: Sage Weil <sage@redhat.com>
cc: Tommi Virtanen <tommi.virtanen@dreamhost.com>
David Howells [Fri, 18 Jul 2014 17:56:35 +0000 (18:56 +0100)]
KEYS: user: Use key preparsing
Make use of key preparsing in user-defined and logon keys so that quota size
determination can take place prior to keyring locking when a key is being
added.
Also the idmapper key types need to change to match as they use the
user-defined key type routines.
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Jeff Layton <jlayton@primarydata.com>
David Howells [Fri, 18 Jul 2014 17:56:34 +0000 (18:56 +0100)]
KEYS: Call ->free_preparse() even after ->preparse() returns an error
Call the ->free_preparse() key type op even after ->preparse() returns an
error as it does cleaning up type stuff.
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Sage Weil <sage@redhat.com>
David Howells [Fri, 18 Jul 2014 17:56:34 +0000 (18:56 +0100)]
KEYS: Allow expiry time to be set when preparsing a key
Allow a key type's preparsing routine to set the expiry time for a key.
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Sage Weil <sage@redhat.com>
David Howells [Fri, 18 Jul 2014 17:56:34 +0000 (18:56 +0100)]
KEYS: struct key_preparsed_payload should have two payload pointers
struct key_preparsed_payload should have two payload pointers to correspond
with those in struct key.
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Sage Weil <sage@redhat.com>
Kees Cook [Thu, 5 Jun 2014 07:23:17 +0000 (00:23 -0700)]
seccomp: implement SECCOMP_FILTER_FLAG_TSYNC
Applying restrictive seccomp filter programs to large or diverse
codebases often requires handling threads which may be started early in
the process lifetime (e.g., by code that is linked in). While it is
possible to apply permissive programs prior to process start up, it is
difficult to further restrict the kernel ABI to those threads after that
point.
This change adds a new seccomp syscall flag to SECCOMP_SET_MODE_FILTER for
synchronizing thread group seccomp filters at filter installation time.
When calling seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC,
filter) an attempt will be made to synchronize all threads in current's
threadgroup to its new seccomp filter program. This is possible iff all
threads are using a filter that is an ancestor to the filter current is
attempting to synchronize to. NULL filters (where the task is running as
SECCOMP_MODE_NONE) are also treated as ancestors allowing threads to be
transitioned into SECCOMP_MODE_FILTER. If prctrl(PR_SET_NO_NEW_PRIVS,
...) has been set on the calling thread, no_new_privs will be set for
all synchronized threads too. On success, 0 is returned. On failure,
the pid of one of the failing threads will be returned and no filters
will have been applied.
The race conditions against another thread are:
- requesting TSYNC (already handled by sighand lock)
- performing a clone (already handled by sighand lock)
- changing its filter (already handled by sighand lock)
- calling exec (handled by cred_guard_mutex)
The clone case is assisted by the fact that new threads will have their
seccomp state duplicated from their parent before appearing on the tasklist.
Holding cred_guard_mutex means that seccomp filters cannot be assigned
while in the middle of another thread's exec (potentially bypassing
no_new_privs or similar). The call to de_thread() may kill threads waiting
for the mutex.
Changes across threads to the filter pointer includes a barrier.
Kees Cook [Fri, 27 Jun 2014 22:01:35 +0000 (15:01 -0700)]
seccomp: allow mode setting across threads
This changes the mode setting helper to allow threads to change the
seccomp mode from another thread. We must maintain barriers to keep
TIF_SECCOMP synchronized with the rest of the seccomp state.
Kees Cook [Fri, 27 Jun 2014 22:18:48 +0000 (15:18 -0700)]
seccomp: introduce writer locking
Normally, task_struct.seccomp.filter is only ever read or modified by
the task that owns it (current). This property aids in fast access
during system call filtering as read access is lockless.
Updating the pointer from another task, however, opens up race
conditions. To allow cross-thread filter pointer updates, writes to the
seccomp fields are now protected by the sighand spinlock (which is shared
by all threads in the thread group). Read access remains lockless because
pointer updates themselves are atomic. However, writes (or cloning)
often entail additional checking (like maximum instruction counts)
which require locking to perform safely.
In the case of cloning threads, the child is invisible to the system
until it enters the task list. To make sure a child can't be cloned from
a thread and left in a prior state, seccomp duplication is additionally
moved under the sighand lock. Then parent and child are certain have
the same seccomp state when they exit the lock.
Based on patches by Will Drewry and David Drysdale.
Kees Cook [Fri, 27 Jun 2014 22:16:33 +0000 (15:16 -0700)]
seccomp: split filter prep from check and apply
In preparation for adding seccomp locking, move filter creation away
from where it is checked and applied. This will allow for locking where
no memory allocation is happening. The validation, filter attachment,
and seccomp mode setting can all happen under the future locks.
For extreme defensiveness, I've added a BUG_ON check for the calculated
size of the buffer allocation in case BPF_MAXINSN ever changes, which
shouldn't ever happen. The compiler should actually optimize out this
check since the test above it makes it impossible.
Kees Cook [Wed, 21 May 2014 22:23:46 +0000 (15:23 -0700)]
sched: move no_new_privs into new atomic flags
Since seccomp transitions between threads requires updates to the
no_new_privs flag to be atomic, the flag must be part of an atomic flag
set. This moves the nnp flag into a separate task field, and introduces
accessors.
Kees Cook [Wed, 25 Jun 2014 23:08:24 +0000 (16:08 -0700)]
seccomp: add "seccomp" syscall
This adds the new "seccomp" syscall with both an "operation" and "flags"
parameter for future expansion. The third argument is a pointer value,
used with the SECCOMP_SET_MODE_FILTER operation. Currently, flags must
be 0. This is functionally equivalent to prctl(PR_SET_SECCOMP, ...).
In addition to the TSYNC flag later in this patch series, there is a
non-zero chance that this syscall could be used for configuring a fixed
argument area for seccomp-tracer-aware processes to pass syscall arguments
in the future. Hence, the use of "seccomp" not simply "seccomp_add_filter"
for this syscall. Additionally, this syscall uses operation, flags,
and user pointer for arguments because strictly passing arguments via
a user pointer would mean seccomp itself would be unable to trivially
filter the seccomp syscall itself.
Kees Cook [Wed, 21 May 2014 22:02:11 +0000 (15:02 -0700)]
seccomp: create internal mode-setting function
In preparation for having other callers of the seccomp mode setting
logic, split the prctl entry point away from the core logic that performs
seccomp mode setting.
David Howells [Fri, 18 Jul 2014 17:56:34 +0000 (18:56 +0100)]
KEYS: Provide a generic instantiation function
Provide a generic instantiation function for key types that use the preparse
hook. This makes it easier to prereserve key quota before keyrings get locked
to retain the new key.
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Sage Weil <sage@redhat.com>
digsig: make crypto builtin if digsig selected as builtin
When SIGNATURE=y but depends on CRYPTO=m, it selects MPILIB as module
producing build break. This patch makes digsig to select crypto for
correcting dependency.
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Signed-off-by: David Howells <dhowells@redhat.com>
Jean Delvare [Thu, 17 Jul 2014 19:45:41 +0000 (20:45 +0100)]
RSA: Don't select non-existent symbol
You can select MPILIB_EXTRA all you want, it doesn't exist ;-)
Surprised kconfig doesn't complain about that...
Signed-off-by: Jean Delvare <jdelvare@suse.de> Acked-by: Marek Vasut <marex@denx.de> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "David S. Miller" <davem@davemloft.net>
David Howells [Thu, 17 Jul 2014 19:45:08 +0000 (20:45 +0100)]
KEYS: Allow special keys (eg. DNS results) to be invalidated by CAP_SYS_ADMIN
Special kernel keys, such as those used to hold DNS results for AFS, CIFS and
NFS and those used to hold idmapper results for NFS, used to be
'invalidateable' with key_revoke(). However, since the default permissions for
keys were reduced:
Add a key flag (KEY_FLAG_ROOT_CAN_INVAL) that will permit a key to be
invalidated by root. This should not be used for system keyrings as the
garbage collector will try and remove any invalidate key. For system keyrings,
KEY_FLAG_ROOT_CAN_CLEAR can be used instead.
After this, from userspace, keyctl_invalidate() and "keyctl invalidate" can be
used by any possessor of CAP_SYS_ADMIN (typically root) to invalidate DNS and
idmapper keys. Invalidated keys are immediately garbage collected and will be
immediately rerequested if needed again.
Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Steve Dickson <steved@redhat.com>
Mimi Zohar [Tue, 13 Aug 2013 12:47:43 +0000 (08:47 -0400)]
ima: define '.ima' as a builtin 'trusted' keyring
Require all keys added to the IMA keyring be signed by an
existing trusted key on the system trusted keyring.
Changelog v6:
- remove ifdef CONFIG_IMA_TRUSTED_KEYRING in C code - Dmitry
- update Kconfig dependency and help
- select KEYS_DEBUG_PROC_KEYS - Dmitry
Changelog v5:
- Move integrity_init_keyring() to init_ima() - Dmitry
- reset keyring[id] on failure - Dmitry
Changelog v1:
- don't link IMA trusted keyring to user keyring
Changelog:
- define stub integrity_init_keyring() function (reported-by Fengguang Wu)
- differentiate between regular and trusted keyring names.
- replace printk with pr_info (D. Kasatkin)
- only make the IMA keyring a trusted keyring (reported-by D. Kastatkin)
- define stub integrity_init_keyring() definition based on
CONFIG_INTEGRITY_SIGNATURE, not CONFIG_INTEGRITY_ASYMMETRIC_KEYS.
(reported-by Jim Davis)
Dmitry Kasatkin [Tue, 17 Jun 2014 08:56:59 +0000 (11:56 +0300)]
KEYS: validate certificate trust only with builtin keys
Instead of allowing public keys, with certificates signed by any
key on the system trusted keyring, to be added to a trusted keyring,
this patch further restricts the certificates to those signed only by
builtin keys on the system keyring.
This patch defines a new option 'builtin' for the kernel parameter
'keys_ownerid' to allow trust validation using builtin keys.
Simplified Mimi's "KEYS: define an owner trusted keyring" patch
Changelog v7:
- rename builtin_keys to use_builtin_keys
Dmitry Kasatkin [Tue, 17 Jun 2014 08:56:58 +0000 (11:56 +0300)]
KEYS: validate certificate trust only with selected key
Instead of allowing public keys, with certificates signed by any
key on the system trusted keyring, to be added to a trusted keyring,
this patch further restricts the certificates to those signed by a
particular key on the system keyring.
This patch defines a new kernel parameter 'ca_keys' to identify the
specific key which must be used for trust validation of certificates.
Simplified Mimi's "KEYS: define an owner trusted keyring" patch.
Changelog:
- support for builtin x509 public keys only
- export "asymmetric_keyid_match"
- remove ifndefs MODULE
- rename kernel boot parameter from keys_ownerid to ca_keys
Dmitry Kasatkin [Tue, 17 Jun 2014 08:56:57 +0000 (11:56 +0300)]
KEYS: make partial key id matching as a dedicated function
To avoid code duplication this patch refactors asymmetric_key_match(),
making partial ID string match a separate function.
This patch also implicitly fixes a bug in the code. asymmetric_key_match()
allows to match the key by its subtype. But subtype matching could be
undone if asymmetric_key_id(key) would return NULL. This patch first
checks for matching spec and then for its value.
Mimi Zohar [Tue, 20 Aug 2013 18:36:27 +0000 (14:36 -0400)]
KEYS: verify a certificate is signed by a 'trusted' key
Only public keys, with certificates signed by an existing
'trusted' key on the system trusted keyring, should be added
to a trusted keyring. This patch adds support for verifying
a certificate's signature.
This is derived from David Howells pkcs7_request_asymmetric_key() patch.
Changelog v6:
- on error free key - Dmitry
- validate trust only for not already trusted keys - Dmitry
- formatting cleanup
Changelog:
- define get_system_trusted_keyring() to fix kbuild issues
Mimi Zohar [Thu, 22 May 2014 18:02:23 +0000 (14:02 -0400)]
KEYS: special dot prefixed keyring name bug fix
Dot prefixed keyring names are supposed to be reserved for the
kernel, but add_key() calls key_get_type_from_user(), which
incorrectly verifies the 'type' field, not the 'description' field.
This patch verifies the 'description' field isn't dot prefixed,
when creating a new keyring, and removes the dot prefix test in
key_get_type_from_user().
Changelog v6:
- whitespace and other cleanup
Changelog v5:
- Only prevent userspace from creating a dot prefixed keyring, not
regular keys - Dmitry
Dmitry Kasatkin [Tue, 6 May 2014 11:47:13 +0000 (14:47 +0300)]
ima: introduce multi-page collect buffers
Use of multiple-page collect buffers reduces:
1) the number of block IO requests
2) the number of asynchronous hash update requests
Second is important for HW accelerated hashing, because significant
amount of time is spent for preparation of hash update operation,
which includes configuring acceleration HW, DMA engine, etc...
Thus, HW accelerators are more efficient when working on large
chunks of data.
This patch introduces usage of multi-page collect buffers. Buffer size
can be specified using 'ahash_bufsize' module parameter. Default buffer
size is 4096 bytes.
Changes in v3:
- kernel parameter replaced with module parameter
Dmitry Kasatkin [Wed, 26 Feb 2014 15:05:20 +0000 (17:05 +0200)]
ima: use ahash API for file hash calculation
Async hash API allows the use of HW acceleration for hash calculation.
It may give significant performance gain and/or reduce power consumption,
which might be very beneficial for battery powered devices.
This patch introduces hash calculation using ahash API. ahash performance
depends on the data size and the particular HW. Depending on the specific
system, shash performance may be better.
This patch defines 'ahash_minsize' module parameter, which is used to
define the minimal file size to use with ahash. If this minimum file size
is not set or the file is smaller than defined by the parameter, shash will
be used.
Changes in v3:
- kernel parameter replaced with module parameter
- pr_crit replaced with pr_crit_ratelimited
- more comment changes - Mimi
Changes in v2:
- ima_ahash_size became as ima_ahash
- ahash pre-allocation moved out from __init code to be able to use
ahash crypto modules. Ahash allocated once on the first use.
- hash calculation falls back to shash if ahash allocation/calculation fails
- complex initialization separated from variable declaration
- improved comments
Dmitry Kasatkin [Fri, 13 Jun 2014 15:55:47 +0000 (18:55 +0300)]
ima: remove unnecessary i_mutex locking from ima_rdwr_violation_check()
Before 2.6.39 inode->i_readcount was maintained by IMA. It was not atomic
and protected using spinlock. For 2.6.39, i_readcount was converted to
atomic and maintaining was moved VFS layer. Spinlock for some unclear
reason was replaced by i_mutex.
After analyzing the code, we came to conclusion that i_mutex locking is
unnecessary, especially when an IMA policy has not been defined.
This patch removes i_mutex locking from ima_rdwr_violation_check().
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