Add a secondary system keyring that can be added to by root whilst the
system is running - provided the key being added is vouched for by a key
built into the kernel or already added to the secondary keyring.

Rename .system_keyring to .builtin_trusted_keys to distinguish it more
obviously from the new keyring (called .secondary_trusted_keys).

The new keyring needs to be enabled with CONFIG_SECONDARY_TRUSTED_KEYRING.

If the secondary keyring is enabled, a link is created from that to
.builtin_trusted_keys so that the the latter will automatically be searched
too if the secondary keyring is searched.
Signed-off-by: NDavid Howells <dhowells@redhat.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>

Make the system trusted keyring depend on the asymmetric key type as
there's not a lot of point having it if you can't then load asymmetric keys
onto it.

This requires the ASYMMETRIC_KEY_TYPE to be made a bool, not a tristate, as
the Kconfig language doesn't then correctly force ASYMMETRIC_KEY_TYPE to
'y' rather than 'm' if SYSTEM_TRUSTED_KEYRING is 'y'.

Making SYSTEM_TRUSTED_KEYRING *select* ASYMMETRIC_KEY_TYPE instead doesn't
work as the Kconfig interpreter then wrongly complains about dependency
loops.
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>

Make the determination of the trustworthiness of a key dependent on whether
a key that can verify it is present in the supplied ring of trusted keys
rather than whether or not the verifying key has KEY_FLAG_TRUSTED set.

verify_pkcs7_signature() will return -ENOKEY if the PKCS#7 message trust
chain cannot be verified.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Generalise system_verify_data() to provide access to internal content
through a callback.  This allows all the PKCS#7 stuff to be hidden inside
this function and removed from the PE file parser and the PKCS#7 test key.

If external content is not required, NULL should be passed as data to the
function.  If the callback is not required, that can be set to NULL.

The function is now called verify_pkcs7_signature() to contrast with
verify_pefile_signature() and the definitions of both have been moved into
linux/verification.h along with the key_being_used_for enum.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix the following warning found by kbuild:

	certs/system_certificates.S:24: Error: misaligned data

because:

	KEYS: Reserve an extra certificate symbol for inserting without recompiling

doesn't correctly align system_extra_cert_used.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Mehmet Kayaalp <mkayaalp@linux.vnet.ibm.com>

Place a system_extra_cert buffer of configurable size, right after the
system_certificate_list, so that inserted keys can be readily processed by
the existing mechanism. Added script takes a key file and a kernel image
and inserts its contents to the reserved area. The
system_certificate_list_size is also adjusted accordingly.

Call the script as:

    scripts/insert-sys-cert -b <vmlinux> -c <certfile>

If vmlinux has no symbol table, supply System.map file with -s flag.
Subsequent runs replace the previously inserted key, instead of appending
the new one.
Signed-off-by: NMehmet Kayaalp <mkayaalp@linux.vnet.ibm.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

When a user calls 'make -s', we can assume they don't want to
see any output except for warnings and errors, but instead
they see this for a warning free build:

 ###
 ### Now generating an X.509 key pair to be used for signing modules.
 ###
 ### If this takes a long time, you might wish to run rngd in the
 ### background to keep the supply of entropy topped up.  It
 ### needs to be run as root, and uses a hardware random
 ### number generator if one is available.
 ###
 Generating a 4096 bit RSA private key
 .................................................................................................................................................................................................................................++
 ..............................................................................................................................++
 writing new private key to 'certs/signing_key.pem'
 -----
 ###
 ### Key pair generated.
 ###

The output can confuse simple build testing scripts that just check
for an empty build log.

This patch silences all the output:
 - "echo" is changed to "@$(kecho)", which is dropped when "-s" gets
   passed
 - the openssl command itself is only printed with V=1, using the
   $(Q) macro
 - The output of openssl gets redirected to /dev/null on "-s" builds.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add KEY_ALLOC_BUILT_IN to convey that a key should have KEY_FLAG_BUILTIN
set rather than setting it after the fact.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Currently we see this in "git status" if we build in the source dir:

Untracked files:
  (use "git add <file>..." to include in what will be committed)

        certs/x509_certificate_list

It looks like it used to live in kernel/ so we squash that .gitignore
entry at the same time.  I didn't bother to dig through git history to
see when it moved, since it is just a minor annoyance at most.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: keyrings@linux-nfs.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Since commit 1329e8cc ("modsign: Extract signing cert from
CONFIG_MODULE_SIG_KEY if needed"), the build system has carefully coped
with the signing key being specified as a relative path in either the
source or or the build trees.

However, the actual signing of modules has not worked if the filename
is relative to the source tree.

Fix that by moving the config_filename helper into scripts/Kbuild.include
so that it can be used from elsewhere, and then using it in the top-level
Makefile to find the signing key file.

Kill the intermediate $(MODPUBKEY) and $(MODSECKEY) variables too, while
we're at it. There's no need for them.
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

We couldn't use if_changed for this before, because it didn't live in
the kernel/ directory so we couldn't add it to $(targets). It was easier
just to leave it as it was.

Now it's in the certs/ directory we can use if_changed, the same as we
do for the trusted certificate list.

Aside from making things consistent, this means we don't need to depend
explicitly on the include/config/module/sig/key.h file. And we also get
to automatically do the right thing and re-extract the cert if the user
does odd things like using a relative filename and then playing silly
buggers with adding/removing that file in both the source and object
trees. We always favour the one in the object tree if it exists, and
now we'll correctly re-extract the cert when it changes. Previously we'd
*only* re-extract the cert if the config option changed, even if the
actual file we're using did change.
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Move certificate handling out of the kernel/ directory and into a certs/
directory to get all the weird stuff in one place and move the generated
signing keys into this directory.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NDavid Woodhouse <David.Woodhouse@intel.com>