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 a new public_key field call key_is_ca.
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>
---
v7: Initial version
v8: Moved key_is_ca after key_is_private, recommended by Mimi
---
crypto/asymmetric_keys/x509_cert_parser.c | 9 +++++++++
include/crypto/public_key.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 6d003096b5bc..f4299b8a4926 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -571,6 +571,15 @@ int x509_process_extension(void *context, size_t hdrlen,
return 0;
}
+ if (ctx->last_oid == OID_basicConstraints) {
+ if (v[0] != (ASN1_CONS_BIT | ASN1_SEQ))
+ return -EBADMSG;
+ if (v[1] != vlen - 2)
+ return -EBADMSG;
+ if (v[1] != 0 && v[2] == ASN1_BOOL && v[3] == 1)
+ ctx->cert->pub->key_is_ca = true;
+ }
+
return 0;
}
diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h
index a9b2e600b7cc..72dcbc06ef9c 100644
--- a/include/crypto/public_key.h
+++ b/include/crypto/public_key.h
@@ -26,6 +26,7 @@ struct public_key {
void *params;
u32 paramlen;
bool key_is_private;
+ bool key_is_ca;
const char *id_type;
const char *pkey_algo;
};
--
2.18.4
