linux.git/include/crypto/public_key.h, branch v7.0

pkcs7: Allow the signing algo to do whatever digestion it wants itself

2026-01-30T11:33:19+00:00

Allow the data to be verified in a PKCS#7 or CMS message to be passed
directly to an asymmetric cipher algorithm (e.g. ML-DSA) if it wants to do
whatever passes for hashing/digestion itself.  The normal digestion of the
data is then skipped as that would be ignored unless another signed info in
the message has some other algorithm that needs it.

The 'data to be verified' may be the content of the PKCS#7 message or it
will be the authenticatedAttributes (signedAttrs if CMS), modified, if
those are present.

This is done by:

 (1) Make ->m and ->m_size point to the data to be verified rather than
     making public_key_verify_signature() access the data directly.  This
     is so that keyctl(KEYCTL_PKEY_VERIFY) will still work.

 (2) Add a flag, ->algo_takes_data, to indicate that the verification
     algorithm wants to access the data to be verified directly rather than
     having it digested first.

 (3) If the PKCS#7 message has authenticatedAttributes (or CMS
     signedAttrs), then the digest contained therein will be validated as
     now, and the modified attrs blob will either be digested or assigned
     to ->m as appropriate.

 (4) If present, always copy and modify the authenticatedAttributes (or
     signedAttrs) then digest that in one go rather than calling the shash
     update twice (once for the tag and once for the rest).

 (5) For ML-DSA, point ->m to the TBSCertificate instead of digesting it
     and using the digest.

Note that whilst ML-DSA does allow for an "external mu", CMS doesn't yet
have that standardised.

Signed-off-by: David Howells 
cc: Lukas Wunner 
cc: Ignat Korchagin 
cc: Stephan Mueller 
cc: Eric Biggers 
cc: Herbert Xu 
cc: keyrings@vger.kernel.org
cc: linux-crypto@vger.kernel.org

pkcs7, x509: Rename ->digest to ->m

2026-01-30T11:33:08+00:00

Rename ->digest and ->digest_len to ->m and ->m_size to represent the input
to the signature verification algorithm, reflecting that ->digest may no
longer actually *be* a digest.

Signed-off-by: David Howells 
Reviewed-by: Jarkko Sakkinen 
cc: Lukas Wunner 
cc: Ignat Korchagin 
cc: Stephan Mueller 
cc: Eric Biggers 
cc: Herbert Xu 
cc: keyrings@vger.kernel.org
cc: linux-crypto@vger.kernel.org

crypto: asymmetric_keys - Remove unused functions

2024-11-02T10:23:24+00:00

encrypt_blob(), decrypt_blob() and create_signature() were some of the
functions added in 2018 by
commit 5a30771832aa ("KEYS: Provide missing asymmetric key subops for new
key type ops [ver #2]")
however, they've not been used.

Remove them.

Signed-off-by: Dr. David Alan Gilbert 
Reviewed-by: Jarkko Sakkinen 
Signed-off-by: Herbert Xu

KEYS: include header for EINVAL definition

2024-01-26T08:39:32+00:00

This patch includes linux/errno.h to address the issue of 'EINVAL' being
undeclared.

Signed-off-by: Clay Chang 
Signed-off-by: Herbert Xu

KEYS: DigitalSignature link restriction

2023-08-17T20:12:20+00:00

Add a new link restriction.  Restrict the addition of keys in a keyring
based on the key having digitalSignature usage set. Additionally, verify
the new certificate against the ones in the system keyrings.  Add two
additional functions to use the new restriction within either the builtin
or secondary keyrings.

[jarkko@kernel.org: Fix checkpatch.pl --strict issues]
Signed-off-by: Eric Snowberg 
Reviewed-and-tested-by: Mimi Zohar 
Reviewed-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen

KEYS: asymmetric: Move sm2 code into x509_public_key

2023-06-23T08:15:37+00:00

The sm2 certificate requires a modified digest.  Move the code
for the hashing from the signature verification path into the
code where we generate the digest.

Signed-off-by: Herbert Xu

KEYS: CA link restriction

2023-04-24T13:15:53+00:00

Add a new link restriction.  Restrict the addition of keys in a keyring
based on the key to be added being a CA.

Signed-off-by: Eric Snowberg 
Reviewed-by: Mimi Zohar 
Reviewed-by: Jarkko Sakkinen 
Tested-by: Mimi Zohar 
Signed-off-by: Jarkko Sakkinen

KEYS: X.509: Parse Key Usage

2023-04-24T13:15:53+00:00

Parse the X.509 Key Usage.  The key usage extension defines the purpose of
the key contained in the certificate.

   id-ce-keyUsage OBJECT IDENTIFIER ::=  { id-ce 15 }

      KeyUsage ::= BIT STRING {
           digitalSignature        (0),
           contentCommitment       (1),
           keyEncipherment         (2),
           dataEncipherment        (3),
           keyAgreement            (4),
           keyCertSign             (5),
           cRLSign                 (6),
           encipherOnly            (7),
           decipherOnly            (8) }

If the keyCertSign or digitalSignature is set, store it in the
public_key structure. Having the purpose of the key being stored
during parsing, allows enforcement on the usage field in the future.
This will be used in a follow on patch that requires knowing the
certificate key usage type.

Link: https://www.rfc-editor.org/rfc/rfc5280#section-4.2.1.3
Signed-off-by: Eric Snowberg 
Reviewed-by: Mimi Zohar 
Reviewed-by: Jarkko Sakkinen 
Tested-by: Mimi Zohar 
Signed-off-by: Jarkko Sakkinen

KEYS: X.509: Parse Basic Constraints for CA

2023-04-24T13:15:53+00:00

Parse the X.509 Basic Constraints.  The basic constraints extension
identifies whether the subject of the certificate is a CA.

BasicConstraints ::= SEQUENCE {
        cA                      BOOLEAN DEFAULT FALSE,
        pathLenConstraint       INTEGER (0..MAX) OPTIONAL }

If the CA is true, store it in the public_key.  This will be used
in a follow on patch that requires knowing if the public key is a CA.

Link: https://www.rfc-editor.org/rfc/rfc5280#section-4.2.1.9
Signed-off-by: Eric Snowberg 
Reviewed-by: Mimi Zohar 
Reviewed-by: Jarkko Sakkinen 
Tested-by: Mimi Zohar 
Signed-off-by: Jarkko Sakkinen

KEYS: Create static version of public_key_verify_signature

2023-04-24T13:15:52+00:00

The kernel test robot reports undefined reference to
public_key_verify_signature when CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE is
not defined. Create a static version in this case and return -EINVAL.

Fixes: db6c43bd2132 ("crypto: KEYS: convert public key and digsig asym to the akcipher api")
Reported-by: kernel test robot 
Signed-off-by: Eric Snowberg 
Reviewed-by: Mimi Zohar 
Reviewed-by: Petr Vorel 
Reviewed-by: Jarkko Sakkinen 
Tested-by: Mimi Zohar 
Signed-off-by: Jarkko Sakkinen