IMA avoids re-measuring files by storing the current state as a flag in
the integrity cache. It will then skip adding a new measurement log entry
if the cache reports the file as already measured.

If a policy measures an already measured file to a new PCR, the measurement
will not be added to the list. This patch implements a new bitfield for
specifying which PCR the file was measured into, rather than if it was
measured.
Signed-off-by: NEric Richter <erichte@linux.vnet.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Template entry duplicates are prevented from being added to the
measurement list by checking a hash table that contains the template
entry digests. However, the PCR value is not included in this comparison,
so duplicate template entry digests with differing PCRs may be dropped.

This patch redefines duplicate template entries as template entries with
the same digest and same PCR values.
Reported-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NEric Richter <erichte@linux.vnet.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

IMA assumes that the same default Kconfig PCR is extended for each
entry. This patch replaces the default configured PCR with the policy
defined PCR.
Signed-off-by: NEric Richter <erichte@linux.vnet.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

The IMA measurement list entries include the Kconfig defined PCR value.
This patch defines a new ima_template_entry field for including the PCR
as specified in the policy rule.
Signed-off-by: NEric Richter <erichte@linux.vnet.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Different policy rules may extend different PCRs. This patch retrieves
the specific PCR for the matched rule.  Subsequent patches will include
the rule specific PCR in the measurement list and extend the appropriate
PCR.
Signed-off-by: NEric Richter <erichte@linux.vnet.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

This patch defines a new IMA measurement policy rule option "pcr=",
which allows extending different PCRs on a per rule basis. For example,
the system independent files could extend the default IMA Kconfig
specified PCR, while the system dependent files could extend a different
PCR.

The following is an example of this usage with an SELinux policy; the
rule would extend PCR 11 with system configuration files:

  measure func=FILE_CHECK mask=MAY_READ obj_type=system_conf_t pcr=11

Changelog v3:
- FIELD_SIZEOF returns bytes, not bits. Fixed INVALID_PCR
Signed-off-by: NEric Richter <erichte@linux.vnet.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

To keep track of which measurements have been extended to which PCRs, this
patch defines a new integrity_iint_cache field named measured_pcrs. This
field is a bitmask of the PCRs measured. Each bit corresponds to a PCR
index. For example, bit 10 corresponds to PCR 10.
Signed-off-by: NEric Richter <erichte@linux.vnet.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Instead of open coded variant re-use extension that vsprintf.c provides
us for ages.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NMatt Fleming <matt@codeblueprint.co.uk>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch fixes the string representation of the LSM/IMA hook enumeration
ordering used for displaying the IMA policy.

Fixes: d9ddf077 ("ima: support for kexec image and initramfs")
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Tested-by: NEric Richter <erichte@linux.vnet.ibm.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

Commit 3034a146 "ima: pass 'opened' flag to identify newly created files"
stopped identifying empty files as new files.  However new empty files
can be created using the mknodat syscall.  On systems with IMA-appraisal
enabled, these empty files are not labeled with security.ima extended
attributes properly, preventing them from subsequently being opened in
order to write the file data contents.  This patch defines a new hook
named ima_post_path_mknod() to mark these empty files, created using
mknodat, as new in order to allow the file data contents to be written.

In addition, files with security.ima xattrs containing a file signature
are considered "immutable" and can not be modified.  The file contents
need to be written, before signing the file.  This patch relaxes this
requirement for new files, allowing the file signature to be written
before the file contents.

Changelog:
- defer identifying files with signatures stored as security.ima
  (based on Dmitry Rozhkov's comments)
- removing tests (eg. dentry, dentry->d_inode, inode->i_size == 0)
  (based on Al's review)
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Al Viro <<viro@zeniv.linux.org.uk>
Tested-by: NDmitry Rozhkov <dmitry.rozhkov@linux.intel.com>

Changing file metadata (eg. uid, guid) could result in having to
re-appraise a file's integrity, but does not change the "new file"
status nor the security.ima xattr.  The IMA_PERMIT_DIRECTIO and
IMA_DIGSIG_REQUIRED flags are policy rule specific.  This patch
only resets these flags, not the IMA_NEW_FILE or IMA_DIGSIG flags.

With this patch, changing the file timestamp will not remove the
file signature on new files.
Reported-by: NDmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Tested-by: NDmitry Rozhkov <dmitry.rozhkov@linux.intel.com>

Commit d43de6c7 ("akcipher: Move the RSA DER encoding check to
the crypto layer") removed the Kconfig option PUBLIC_KEY_ALGO_RSA,
but forgot to remove a 'select' to this option in the definition of
INTEGRITY_ASYMMETRIC_KEYS.

Let's remove the select, as it's ineffective now.
Signed-off-by: NAndreas Ziegler <andreas.ziegler@fau.de>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a config option (IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY)
that, when enabled, allows keys to be added to the IMA keyrings by
userspace - with the restriction that each must be signed by a key in the
system trusted keyrings.

EPERM will be returned if this option is disabled, ENOKEY will be returned if
no authoritative key can be found and EKEYREJECTED will be returned if the
signature doesn't match.  Other errors such as ENOPKG may also be returned.

If this new option is enabled, the builtin system keyring is searched, as is
the secondary system keyring if that is also enabled.  Intermediate keys
between the builtin system keyring and the key being added can be added to
the secondary keyring (which replaces .ima_mok) to form a trust chain -
provided they are also validly signed by a key in one of the trusted keyrings.

The .ima_mok keyring is then removed and the IMA blacklist keyring gets its
own config option (IMA_BLACKLIST_KEYRING).
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Remove KEY_FLAG_TRUSTED and KEY_ALLOC_TRUSTED as they're no longer
meaningful.  Also we can drop the trusted flag from the preparse structure.

Given this, we no longer need to pass the key flags through to
restrict_link().

Further, we can now get rid of keyring_restrict_trusted_only() also.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Move the point at which a key is determined to be trustworthy to
__key_link() so that we use the contents of the keyring being linked in to
to determine whether the key being linked in is trusted or not.

What is 'trusted' then becomes a matter of what's in the keyring.

Currently, the test is done when the key is parsed, but given that at that
point we can only sensibly refer to the contents of the system trusted
keyring, we can only use that as the basis for working out the
trustworthiness of a new key.

With this change, a trusted keyring is a set of keys that once the
trusted-only flag is set cannot be added to except by verification through
one of the contained keys.

Further, adding a key into a trusted keyring, whilst it might grant
trustworthiness in the context of that keyring, does not automatically
grant trustworthiness in the context of a second keyring to which it could
be secondarily linked.

To accomplish this, the authentication data associated with the key source
must now be retained.  For an X.509 cert, this means the contents of the
AuthorityKeyIdentifier and the signature data.


If system keyrings are disabled then restrict_link_by_builtin_trusted()
resolves to restrict_link_reject().  The integrity digital signature code
still works correctly with this as it was previously using
KEY_FLAG_TRUSTED_ONLY, which doesn't permit anything to be added if there
is no system keyring against which trust can be determined.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a facility whereby proposed new links to be added to a keyring can be
vetted, permitting them to be rejected if necessary.  This can be used to
block public keys from which the signature cannot be verified or for which
the signature verification fails.  It could also be used to provide
blacklisting.

This affects operations like add_key(), KEYCTL_LINK and KEYCTL_INSTANTIATE.

To this end:

 (1) A function pointer is added to the key struct that, if set, points to
     the vetting function.  This is called as:

	int (*restrict_link)(struct key *keyring,
			     const struct key_type *key_type,
			     unsigned long key_flags,
			     const union key_payload *key_payload),

     where 'keyring' will be the keyring being added to, key_type and
     key_payload will describe the key being added and key_flags[*] can be
     AND'ed with KEY_FLAG_TRUSTED.

     [*] This parameter will be removed in a later patch when
     	 KEY_FLAG_TRUSTED is removed.

     The function should return 0 to allow the link to take place or an
     error (typically -ENOKEY, -ENOPKG or -EKEYREJECTED) to reject the
     link.

     The pointer should not be set directly, but rather should be set
     through keyring_alloc().

     Note that if called during add_key(), preparse is called before this
     method, but a key isn't actually allocated until after this function
     is called.

 (2) KEY_ALLOC_BYPASS_RESTRICTION is added.  This can be passed to
     key_create_or_update() or key_instantiate_and_link() to bypass the
     restriction check.

 (3) KEY_FLAG_TRUSTED_ONLY is removed.  The entire contents of a keyring
     with this restriction emplaced can be considered 'trustworthy' by
     virtue of being in the keyring when that keyring is consulted.

 (4) key_alloc() and keyring_alloc() take an extra argument that will be
     used to set restrict_link in the new key.  This ensures that the
     pointer is set before the key is published, thus preventing a window
     of unrestrictedness.  Normally this argument will be NULL.

 (5) As a temporary affair, keyring_restrict_trusted_only() is added.  It
     should be passed to keyring_alloc() as the extra argument instead of
     setting KEY_FLAG_TRUSTED_ONLY on a keyring.  This will be replaced in
     a later patch with functions that look in the appropriate places for
     authoritative keys.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

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

... and neither can ever be NULL
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

Make the identifier public key and digest algorithm fields text instead of
enum.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>

Move the RSA EMSA-PKCS1-v1_5 encoding from the asymmetric-key public_key
subtype to the rsa crypto module's pkcs1pad template.  This means that the
public_key subtype no longer has any dependencies on public key type.

To make this work, the following changes have been made:

 (1) The rsa pkcs1pad template is now used for RSA keys.  This strips off the
     padding and returns just the message hash.

 (2) In a previous patch, the pkcs1pad template gained an optional second
     parameter that, if given, specifies the hash used.  We now give this,
     and pkcs1pad checks the encoded message E(M) for the EMSA-PKCS1-v1_5
     encoding and verifies that the correct digest OID is present.

 (3) The crypto driver in crypto/asymmetric_keys/rsa.c is now reduced to
     something that doesn't care about what the encryption actually does
     and and has been merged into public_key.c.

 (4) CONFIG_PUBLIC_KEY_ALGO_RSA is gone.  Module signing must set
     CONFIG_CRYPTO_RSA=y instead.

Thoughts:

 (*) Should the encoding style (eg. raw, EMSA-PKCS1-v1_5) also be passed to
     the padding template?  Should there be multiple padding templates
     registered that share most of the code?
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NTadeusz Struk <tadeusz.struk@intel.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>

Require the IMA policy to be signed when additional rules can be added.

v1:
- initialize the policy flag
- include IMA_APPRAISE_POLICY in the policy flag
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NPetko Manolov <petkan@mip-labs.com>
Acked-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>

Add support for measuring and appraising the IMA policy itself.

Changelog v4:
- use braces on both if/else branches, even if single line on one of the
branches - Dmitry
- Use the id mapping - Dmitry
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NPetko Manolov <petkan@mip-labs.com>
Acked-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>

We currently cannot do appraisal or signature vetting of IMA policies
since we currently can only load IMA policies by writing the contents
of the policy directly in, as follows:

cat policy-file > <securityfs>/ima/policy

If we provide the kernel the path to the IMA policy so it can load
the policy itself it'd be able to later appraise or vet the file
signature if it has one.  This patch adds support to load the IMA
policy with a given path as follows:

echo /etc/ima/ima_policy > /sys/kernel/security/ima/policy

Changelog v4+:
- moved kernel_read_file_from_path() error messages to callers
v3:
- moved kernel_read_file_from_path() to a separate patch
v2:
- after re-ordering the patches, replace calling integrity_kernel_read()
  to read the file with kernel_read_file_from_path() (Mimi)
- Patch description re-written by Luis R. Rodriguez
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Add IMA policy support for measuring/appraising the kexec image and
initramfs. Two new IMA policy identifiers KEXEC_KERNEL_CHECK and
KEXEC_INITRAMFS_CHECK are defined.

Example policy rules:
measure func=KEXEC_KERNEL_CHECK
appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig
measure func=KEXEC_INITRAMFS_CHECK
appraise func=KEXEC_INITRAMFS_CHECK appraise_type=imasig

Moving the enumeration to the vfs layer simplified the patches, allowing
the IMA changes, for the most part, to be separated from the other
changes.  Unfortunately, passing either a kernel_read_file_id or a
ima_hooks enumeration within IMA is messy.

Option 1: duplicate kernel_read_file enumeration in ima_hooks

enum kernel_read_file_id {
	...
        READING_KEXEC_IMAGE,
        READING_KEXEC_INITRAMFS,
        READING_MAX_ID

enum ima_hooks {
	...
	KEXEC_KERNEL_CHECK
	KEXEC_INITRAMFS_CHECK

Option 2: define ima_hooks as extension of kernel_read_file
eg: enum ima_hooks {
        FILE_CHECK = READING_MAX_ID,
        MMAP_CHECK,

In order to pass both kernel_read_file_id and ima_hooks values, we
would need to specify a struct containing a union.

struct caller_id {
        union {
                enum ima_hooks func_id;
                enum kernel_read_file_id read_id;
        };
};

Option 3: incorportate the ima_hooks enumeration into kernel_read_file_id,
perhaps changing the enumeration name.

For now, duplicate the new READING_KEXEC_IMAGE/INITRAMFS in the ima_hooks.

Changelog v4:
- replaced switch statement with a kernel_read_file_id to an ima_hooks
id mapping array - Dmitry
- renamed ima_hook tokens KEXEC_CHECK and INITRAMFS_CHECK to
KEXEC_KERNEL_CHECK and KEXEC_INITRAMFS_CHECK respectively - Dave Young
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NPetko Manolov <petkan@mip-labs.com>
Acked-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>
Cc: Dave Young <dyoung@redhat.com>

Each time a file is read by the kernel, the file should be re-measured and
the file signature re-appraised, based on policy.  As there is no need to
preserve the status information, this patch replaces the firmware and
module specific cache status with a generic one named read_file.

This change simplifies adding support for other files read by the kernel.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NPetko Manolov <petkan@mip-labs.com>
Acked-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>

Replace copy_module_from_fd() with kernel_read_file_from_fd().

Although none of the upstreamed LSMs define a kernel_module_from_file
hook, IMA is called, based on policy, to prevent unsigned kernel modules
from being loaded by the original kernel module syscall and to
measure/appraise signed kernel modules.

The security function security_kernel_module_from_file() was called prior
to reading a kernel module.  Preventing unsigned kernel modules from being
loaded by the original kernel module syscall remains on the pre-read
kernel_read_file() security hook.  Instead of reading the kernel module
twice, once for measuring/appraising and again for loading the kernel
module, the signature validation is moved to the kernel_post_read_file()
security hook.

This patch removes the security_kernel_module_from_file() hook and security
call.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>

The kernel_read_file security hook is called prior to reading the file
into memory.

Changelog v4+:
- export security_kernel_read_file()
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>

Replace the fw_read_file_contents with kernel_file_read_from_path().

Although none of the upstreamed LSMs define a kernel_fw_from_file hook,
IMA is called by the security function to prevent unsigned firmware from
being loaded and to measure/appraise signed firmware, based on policy.

Instead of reading the firmware twice, once for measuring/appraising the
firmware and again for reading the firmware contents into memory, the
kernel_post_read_file() security hook calculates the file hash based on
the in memory file buffer.  The firmware is read once.

This patch removes the LSM kernel_fw_from_file() hook and security call.

Changelog v4+:
- revert dropped buf->size assignment - reported by Sergey Senozhatsky
v3:
- remove kernel_fw_from_file hook
- use kernel_file_read_from_path() - requested by Luis
v2:
- reordered and squashed firmware patches
- fix MAX firmware size (Kees Cook)
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NLuis R. Rodriguez <mcgrof@kernel.org>

This patch defines a new IMA hook ima_post_read_file() for measuring
and appraising files read by the kernel. The caller loads the file into
memory before calling this function, which calculates the hash followed by
the normal IMA policy based processing.

Changelog v5:
- fail ima_post_read_file() if either file or buf is NULL
v3:
- rename ima_hash_and_process_file() to ima_post_read_file()

v1:
- split patch
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>

Setting up ahash has some overhead.  Only use ahash to calculate the
hash of a buffer, if the buffer is larger than ima_ahash_minsize.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>

This patch provides convenient buffer hash calculation function.

Changelog v3:
- fix while hash calculation - Dmitry
v1:
- rewrite to support loff_t sized buffers - Mimi
  (based on Fenguang Wu's testing)
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Cleanup the function arguments by using "ima_hooks" enumerator as needed.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NPetko Manolov <petkan@mip-labs.com>
Acked-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>

Define and call a function to display the "ima_hooks" rules.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NPetko Manolov <petkan@mip-labs.com>
Acked-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>

Instead of passing pointers to pointers to ima_collect_measurent() to
read and return the 'security.ima' xattr value, this patch moves the
functionality to the calling process_measurement() to directly read
the xattr and pass only the hash algo to the ima_collect_measurement().
Signed-off-by: NDmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Convert asymmetric_verify to akcipher api.
Signed-off-by: NTadeusz Struk <tadeusz.struk@intel.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

This patch fixes vulnerability CVE-2016-2085.  The problem exists
because the vm_verify_hmac() function includes a use of memcmp().
Unfortunately, this allows timing side channel attacks; specifically
a MAC forgery complexity drop from 2^128 to 2^12.  This patch changes
the memcmp() to the cryptographically safe crypto_memneq().
Reported-by: NXiaofei Rex Guo <xiaofei.rex.guo@intel.com>
Signed-off-by: NRyan Ware <ware@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

CONFIG_KEYS_DEBUG_PROC_KEYS is no longer an option as /proc/keys is now
mandatory if the keyrings facility is enabled (it's used by libkeyutils in
userspace).

The defconfig references were removed with:

	perl -p -i -e 's/CONFIG_KEYS_DEBUG_PROC_KEYS=y\n//' \
	    `git grep -l CONFIG_KEYS_DEBUG_PROC_KEYS=y`

and the integrity Kconfig fixed by hand.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Andreas Ziegler <andreas.ziegler@fau.de>
cc: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>

This needs to go through the security tree so I'm reverting the
patches for now.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

ima_check_policy() has no parameters, so use the normal void
parameter convention to make it match the prototype in the header file
security/integrity/ima/ima.h
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>