Point to the public_key_signature struct from the pkcs7_signed_info struct
rather than embedding it.  This makes the code consistent with the X.509
signature handling and makes it possible to have a common cleanup function.

We also save a copy of the digest in the signature without sharing the
memory with the crypto layer metadata.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Retain the key verification data (ie. the struct public_key_signature)
including the digest and the key identifiers.

Note that this means that we need to take a separate copy of the digest in
x509_get_sig_params() rather than lumping it in with the crypto layer data.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

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>

This patch converts the module verification code to the new 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 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>

This patch converts the module verification code to the new akcipher API.
Signed-off-by: NTadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

On sparc, we see unaligned access messages on each modprobe[-r]:

Kernel unaligned access at TPC[6ad9b4] pkcs7_verify [..]
Kernel unaligned access at TPC[6a5484] crypto_shash_finup [..]
Kernel unaligned access at TPC[6a5390] crypto_shash_update [..]
Kernel unaligned access at TPC[10150308] sha1_sparc64_update [..]
Kernel unaligned access at TPC[101501ac] __sha1_sparc64_update [..]

These ware triggered by mod_verify_sig() invocations of pkcs_verify(), and
are are being caused by an unaligned desc at (sha1, digest_size is 0x14)
        desc = digest + digest_size;

To fix this, pkcs7_verify needs to make sure that desc is pointing
at an aligned value past the digest_size, and kzalloc appropriately,
taking alignment values into consideration.
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

A PKCS#7 or CMS message can have per-signature authenticated attributes
that are digested as a lump and signed by the authorising key for that
signature.  If such attributes exist, the content digest isn't itself
signed, but rather it is included in a special authattr which then
contributes to the signature.

Further, we already require the master message content type to be
pkcs7_signedData - but there's also a separate content type for the data
itself within the SignedData object and this must be repeated inside the
authattrs for each signer [RFC2315 9.2, RFC5652 11.1].

We should really validate the authattrs if they exist or forbid them
entirely as appropriate.  To this end:

 (1) Alter the PKCS#7 parser to reject any message that has more than one
     signature where at least one signature has authattrs and at least one
     that does not.

 (2) Validate authattrs if they are present and strongly restrict them.
     Only the following authattrs are permitted and all others are
     rejected:

     (a) contentType.  This is checked to be an OID that matches the
     	 content type in the SignedData object.

     (b) messageDigest.  This must match the crypto digest of the data.

     (c) signingTime.  If present, we check that this is a valid, parseable
     	 UTCTime or GeneralTime and that the date it encodes fits within
     	 the validity window of the matching X.509 cert.

     (d) S/MIME capabilities.  We don't check the contents.

     (e) Authenticode SP Opus Info.  We don't check the contents.

     (f) Authenticode Statement Type.  We don't check the contents.

     The message is rejected if (a) or (b) are missing.  If the message is
     an Authenticode type, the message is rejected if (e) is missing; if
     not Authenticode, the message is rejected if (d) - (f) are present.

     The S/MIME capabilities authattr (d) unfortunately has to be allowed
     to support kernels already signed by the pesign program.  This only
     affects kexec.  sign-file suppresses them (CMS_NOSMIMECAP).

     The message is also rejected if an authattr is given more than once or
     if it contains more than one element in its set of values.

 (3) Add a parameter to pkcs7_verify() to select one of the following
     restrictions and pass in the appropriate option from the callers:

     (*) VERIFYING_MODULE_SIGNATURE

	 This requires that the SignedData content type be pkcs7-data and
	 forbids authattrs.  sign-file sets CMS_NOATTR.  We could be more
	 flexible and permit authattrs optionally, but only permit minimal
	 content.

     (*) VERIFYING_FIRMWARE_SIGNATURE

	 This requires that the SignedData content type be pkcs7-data and
	 requires authattrs.  In future, this will require an attribute
	 holding the target firmware name in addition to the minimal set.

     (*) VERIFYING_UNSPECIFIED_SIGNATURE

	 This requires that the SignedData content type be pkcs7-data but
	 allows either no authattrs or only permits the minimal set.

     (*) VERIFYING_KEXEC_PE_SIGNATURE

	 This only supports the Authenticode SPC_INDIRECT_DATA content type
	 and requires at least an SpcSpOpusInfo authattr in addition to the
	 minimal set.  It also permits an SPC_STATEMENT_TYPE authattr (and
	 an S/MIME capabilities authattr because the pesign program doesn't
	 remove these).

     (*) VERIFYING_KEY_SIGNATURE
     (*) VERIFYING_KEY_SELF_SIGNATURE

	 These are invalid in this context but are included for later use
	 when limiting the use of X.509 certs.

 (4) The pkcs7_test key type is given a module parameter to select between
     the above options for testing purposes.  For example:

	echo 1 >/sys/module/pkcs7_test_key/parameters/usage
	keyctl padd pkcs7_test foo @s </tmp/stuff.pkcs7

     will attempt to check the signature on stuff.pkcs7 as if it contains a
     firmware blob (1 being VERIFYING_FIRMWARE_SIGNATURE).
Suggested-by: NAndy Lutomirski <luto@kernel.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NMarcel Holtmann <marcel@holtmann.org>
Reviewed-by: NDavid Woodhouse <David.Woodhouse@intel.com>

It is possible for a PKCS#7 message to have detached data.  However, to verify
the signatures on a PKCS#7 message, we have to be able to digest the data.
Provide a function to supply that data.  An error is given if the PKCS#7
message included embedded data.

This is used in a subsequent patch to supply the data to module signing where
the signature is in the form of a PKCS#7 message with detached data, whereby
the detached data is the module content that is signed.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Tested-by: NVivek Goyal <vgoyal@redhat.com>

If an X.509 certificate has an AuthorityKeyIdentifier extension that provides
an issuer and serialNumber, then make it so that these are used in preference
to the keyIdentifier field also held therein for searching for the signing
certificate.

If both the issuer+serialNumber and the keyIdentifier are supplied, then the
certificate is looked up by the former but the latter is checked as well.  If
the latter doesn't match the subjectKeyIdentifier of the parent certificate,
EKEYREJECTED is returned.

This makes it possible to chain X.509 certificates based on the issuer and
serialNumber fields rather than on subjectKeyIdentifier.  This is necessary as
we are having to deal with keys that are represented by X.509 certificates
that lack a subjectKeyIdentifier.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Tested-by: NVivek Goyal <vgoyal@redhat.com>

Extract both parts of the AuthorityKeyIdentifier, not just the keyIdentifier,
as the second part can be used to match X.509 certificates by issuer and
serialNumber.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Tested-by: NVivek Goyal <vgoyal@redhat.com>

The X.509 certificate list in a PKCS#7 message is optional.  To save space, we
can omit the inclusion of any X.509 certificates if we are sure that we can
look the relevant public key up by the serial number and issuer given in a
signed info block.

This also supports use of a signed info block for which we can't find a
matching X.509 cert in the certificate list, though it be populated.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>

Provide better handling of unsupported crypto when verifying a PKCS#7 message.
If we can't bridge the gap between a pair of X.509 certs or between a signed
info block and an X.509 cert because it involves some crypto we don't support,
that's not necessarily the end of the world as there may be other ways points
at which we can intersect with a ring of trusted keys.

Instead, only produce ENOPKG immediately if all the signed info blocks in a
PKCS#7 message require unsupported crypto to bridge to the first X.509 cert.
Otherwise, we defer the generation of ENOPKG until we get ENOKEY during trust
validation.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>

Make use of the new match string preparsing to overhaul key identification
when searching for asymmetric keys.  The following changes are made:

 (1) Use the previously created asymmetric_key_id struct to hold the following
     key IDs derived from the X.509 certificate or PKCS#7 message:

	id: serial number + issuer
	skid: subjKeyId + subject
	authority: authKeyId + issuer

 (2) Replace the hex fingerprint attached to key->type_data[1] with an
     asymmetric_key_ids struct containing the id and the skid (if present).

 (3) Make the asymmetric_type match data preparse select one of two searches:

     (a) An iterative search for the key ID given if prefixed with "id:".  The
     	 prefix is expected to be followed by a hex string giving the ID to
     	 search for.  The criterion key ID is checked against all key IDs
     	 recorded on the key.

     (b) A direct search if the key ID is not prefixed with "id:".  This will
     	 look for an exact match on the key description.

 (4) Make x509_request_asymmetric_key() take a key ID.  This is then converted
     into "id:<hex>" and passed into keyring_search() where match preparsing
     will turn it back into a binary ID.

 (5) X.509 certificate verification then takes the authority key ID and looks
     up a key that matches it to find the public key for the certificate
     signature.

 (6) PKCS#7 certificate verification then takes the id key ID and looks up a
     key that matches it to find the public key for the signed information
     block signature.

Additional changes:

 (1) Multiple subjKeyId and authKeyId values on an X.509 certificate cause the
     cert to be rejected with -EBADMSG.

 (2) The 'fingerprint' ID is gone.  This was primarily intended to convey PGP
     public key fingerprints.  If PGP is supported in future, this should
     generate a key ID that carries the fingerprint.

 (3) Th ca_keyid= kernel command line option is now converted to a key ID and
     used to match the authority key ID.  Possibly this should only match the
     actual authKeyId part and not the issuer as well.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>

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: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>

Verify certificate chain in the X.509 certificates contained within the PKCS#7
message as far as possible.  If any signature that we should be able to verify
fails, we reject the whole lot.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Reviewed-by: NKees Cook <keescook@chromium.org>

Find the appropriate key in the PKCS#7 key list and verify the signature with
it.  There may be several keys in there forming a chain.  Any link in that
chain or the root of that chain may be in our keyrings.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Reviewed-by: NKees Cook <keescook@chromium.org>

Digest the data in a PKCS#7 signed-data message and attach to the
public_key_signature struct contained in the pkcs7_message struct.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Reviewed-by: NKees Cook <keescook@chromium.org>