| Message ID | 20230207025958.974056-4-eric.snowberg@oracle.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add CA enforcement keyring restrictions | expand |
On Mon, 2023-02-06 at 21:59 -0500, Eric Snowberg wrote: > 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 <eric.snowberg@oracle.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
On Mon, Feb 06, 2023 at 09:59:55PM -0500, Eric Snowberg wrote: > 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 <eric.snowberg@oracle.com> > --- > crypto/asymmetric_keys/x509_cert_parser.c | 22 ++++++++++++++++++++++ > include/crypto/public_key.h | 2 ++ > 2 files changed, 24 insertions(+) > > diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c > index 7a9b084e2043..77547d4bd94d 100644 > --- a/crypto/asymmetric_keys/x509_cert_parser.c > +++ b/crypto/asymmetric_keys/x509_cert_parser.c > @@ -586,6 +586,28 @@ int x509_process_extension(void *context, size_t hdrlen, > return 0; > } > > + if (ctx->last_oid == OID_basicConstraints) { > + /* > + * Get hold of the basicConstraints > + * v[1] is the encoding size > + * (Expect 0x2 or greater, making it 1 or more bytes) > + * v[2] is the encoding type > + * (Expect an ASN1_BOOL for the CA) > + * v[3] is the contents of the ASN1_BOOL > + * (Expect 1 if the CA is TRUE) > + * vlen should match the entire extension size > + */ > + if (v[0] != (ASN1_CONS_BIT | ASN1_SEQ)) > + return -EBADMSG; > + if (vlen < 2) > + return -EBADMSG; > + if (v[1] != vlen - 2) > + return -EBADMSG; > + if (vlen >= 4 && v[1] != 0 && v[2] == ASN1_BOOL && v[3] == 1) > + ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_CA; > + return 0; > + } > + > return 0; > } > > diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h > index 6d61695e1cde..c401762850f2 100644 > --- a/include/crypto/public_key.h > +++ b/include/crypto/public_key.h > @@ -28,6 +28,8 @@ struct public_key { > bool key_is_private; > const char *id_type; > const char *pkey_algo; > + unsigned long key_eflags; /* key extension flags */ > +#define KEY_EFLAG_CA 0 /* set if the CA basic constraints is set */ > }; > > extern void public_key_free(struct public_key *key); > -- > 2.27.0 > Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> BR, Jarkko
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c index 7a9b084e2043..77547d4bd94d 100644 --- a/crypto/asymmetric_keys/x509_cert_parser.c +++ b/crypto/asymmetric_keys/x509_cert_parser.c @@ -586,6 +586,28 @@ int x509_process_extension(void *context, size_t hdrlen, return 0; } + if (ctx->last_oid == OID_basicConstraints) { + /* + * Get hold of the basicConstraints + * v[1] is the encoding size + * (Expect 0x2 or greater, making it 1 or more bytes) + * v[2] is the encoding type + * (Expect an ASN1_BOOL for the CA) + * v[3] is the contents of the ASN1_BOOL + * (Expect 1 if the CA is TRUE) + * vlen should match the entire extension size + */ + if (v[0] != (ASN1_CONS_BIT | ASN1_SEQ)) + return -EBADMSG; + if (vlen < 2) + return -EBADMSG; + if (v[1] != vlen - 2) + return -EBADMSG; + if (vlen >= 4 && v[1] != 0 && v[2] == ASN1_BOOL && v[3] == 1) + ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_CA; + return 0; + } + return 0; } diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h index 6d61695e1cde..c401762850f2 100644 --- a/include/crypto/public_key.h +++ b/include/crypto/public_key.h @@ -28,6 +28,8 @@ struct public_key { bool key_is_private; const char *id_type; const char *pkey_algo; + unsigned long key_eflags; /* key extension flags */ +#define KEY_EFLAG_CA 0 /* set if the CA basic constraints is set */ }; extern void public_key_free(struct public_key *key);
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 <eric.snowberg@oracle.com> --- crypto/asymmetric_keys/x509_cert_parser.c | 22 ++++++++++++++++++++++ include/crypto/public_key.h | 2 ++ 2 files changed, 24 insertions(+)