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 x509_certificate. This will be used
in a follow on patch that requires knowing if the public key is a CA.
Signed-off-by: Eric Snowberg <eric.snowberg@xxxxxxxxxx>
---
crypto/asymmetric_keys/x509_cert_parser.c | 9 +++++++++
crypto/asymmetric_keys/x509_parser.h | 1 +
2 files changed, 10 insertions(+)
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 2899ed80bb18..30f7374ea9c0 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -583,6 +583,15 @@ int x509_process_extension(void *context, size_t hdrlen,
return 0;
}
+ if (ctx->last_oid == OID_basicConstraints) {
+ if (vlen < 2 || v[0] != (ASN1_CONS_BIT | ASN1_SEQ))
+ return -EBADMSG;
+ if (v[1] != vlen - 2)
+ return -EBADMSG;
+ if (vlen >= 4 && v[1] != 0 && v[2] == ASN1_BOOL && v[3] == 1)
+ ctx->cert->is_root_ca = true;
+ }
+
return 0;
}
diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h
index 97a886cbe01c..dc45df9f6594 100644
--- a/crypto/asymmetric_keys/x509_parser.h
+++ b/crypto/asymmetric_keys/x509_parser.h
@@ -38,6 +38,7 @@ struct x509_certificate {
bool self_signed; /* T if self-signed (check unsupported_sig too) */
bool unsupported_sig; /* T if signature uses unsupported crypto */
bool blacklisted;
+ bool is_root_ca; /* T if basic constraints CA is set */
};
/*
--
2.27.0
