From: Eric Snowberg <eric.snowberg@oracle.com>
To: jarkko@kernel.org, zohar@linux.ibm.com, dhowells@redhat.com,
dwmw2@infradead.org
Cc: herbert@gondor.apana.org.au, davem@davemloft.net,
dmitry.kasatkin@gmail.com, paul@paul-moore.com,
jmorris@namei.org, serge@hallyn.com, pvorel@suse.cz,
tadeusz.struk@intel.com, eric.snowberg@oracle.com,
kanth.ghatraju@oracle.com, konrad.wilk@oracle.com,
erpalmer@linux.vnet.ibm.com, coxu@redhat.com,
keyrings@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: [PATCH v4 3/6] KEYS: X.509: Parse Basic Constraints for CA
Date: Mon, 6 Feb 2023 21:59:55 -0500 [thread overview]
Message-ID: <20230207025958.974056-4-eric.snowberg@oracle.com> (raw)
In-Reply-To: <20230207025958.974056-1-eric.snowberg@oracle.com>
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
next prev parent reply other threads:[~2023-02-07 3:00 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-07 2:59 [PATCH v4 0/6] Add CA enforcement keyring restrictions Eric Snowberg
2023-02-07 2:59 ` [PATCH v4 1/6] KEYS: Create static version of public_key_verify_signature Eric Snowberg
2023-02-10 3:39 ` Jarkko Sakkinen
2023-02-10 22:38 ` Eric Snowberg
2023-02-07 2:59 ` [PATCH v4 2/6] KEYS: Add missing function documentation Eric Snowberg
2023-02-08 21:48 ` Mimi Zohar
2023-02-10 3:40 ` Jarkko Sakkinen
2023-02-07 2:59 ` Eric Snowberg [this message]
2023-02-08 21:01 ` [PATCH v4 3/6] KEYS: X.509: Parse Basic Constraints for CA Mimi Zohar
2023-02-10 3:46 ` Jarkko Sakkinen
2023-02-07 2:59 ` [PATCH v4 4/6] KEYS: X.509: Parse Key Usage Eric Snowberg
2023-02-08 21:02 ` Mimi Zohar
2023-02-10 3:48 ` Jarkko Sakkinen
2023-02-10 22:39 ` Eric Snowberg
2023-02-07 2:59 ` [PATCH v4 5/6] KEYS: CA link restriction Eric Snowberg
2023-02-09 2:55 ` Mimi Zohar
2023-02-07 2:59 ` [PATCH v4 6/6] integrity: machine keyring CA configuration Eric Snowberg
2023-02-10 13:05 ` Mimi Zohar
2023-02-10 22:42 ` Eric Snowberg
2023-02-13 7:54 ` Jarkko Sakkinen
2023-02-14 21:24 ` Eric Snowberg
2023-02-08 12:38 ` [PATCH v4 0/6] Add CA enforcement keyring restrictions Mimi Zohar
2023-02-08 23:26 ` Eric Snowberg
2023-02-09 2:54 ` Mimi Zohar
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