From: Dmitry Kasatkin <d.kasatkin@samsung.com>
To: zohar@linux.vnet.ibm.com, dhowells@redhat.com, jmorris@namei.org
Cc: roberto.sassu@polito.it, linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org,
Dmitry Kasatkin <d.kasatkin@samsung.com>
Subject: [PATCH 01/20] KEYS: verify a certificate is signed by a 'trusted' key
Date: Wed, 23 Apr 2014 16:30:19 +0300 [thread overview]
Message-ID: <0f7915604c69374f15cbaf36c499a5d88264e89d.1398259638.git.d.kasatkin@samsung.com> (raw)
In-Reply-To: <cover.1398259638.git.d.kasatkin@samsung.com>
In-Reply-To: <cover.1398259638.git.d.kasatkin@samsung.com>
From: Mimi Zohar <zohar@linux.vnet.ibm.com>
Only public keys, with certificates signed by an existing
'trusted' key on the system trusted keyring, should be added
to a trusted keyring. This patch adds support for verifying
a certificate's signature.
This is derived from David Howells pkcs7_request_asymmetric_key() patch.
Changes:
- Flaged out the code to prevent build break if system keyring
is not enabled (Dmitry).
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
---
crypto/asymmetric_keys/x509_public_key.c | 85 +++++++++++++++++++++++++++++++-
1 file changed, 84 insertions(+), 1 deletion(-)
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index 382ef0d..d279f43 100644
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -18,6 +18,7 @@
#include <linux/asn1_decoder.h>
#include <keys/asymmetric-subtype.h>
#include <keys/asymmetric-parser.h>
+#include <keys/system_keyring.h>
#include <crypto/hash.h>
#include "asymmetric_keys.h"
#include "public_key.h"
@@ -102,6 +103,82 @@ int x509_check_signature(const struct public_key *pub,
}
EXPORT_SYMBOL_GPL(x509_check_signature);
+#ifdef CONFIG_SYSTEM_TRUSTED_KEYRING
+/*
+ * Find a key in the given keyring by issuer and authority.
+ */
+static struct key *x509_request_asymmetric_key(
+ struct key *keyring,
+ const char *signer, size_t signer_len,
+ const char *authority, size_t auth_len)
+{
+ key_ref_t key;
+ char *id;
+
+ /* Construct an identifier. */
+ id = kmalloc(signer_len + 2 + auth_len + 1, GFP_KERNEL);
+ if (!id)
+ return ERR_PTR(-ENOMEM);
+
+ memcpy(id, signer, signer_len);
+ id[signer_len + 0] = ':';
+ id[signer_len + 1] = ' ';
+ memcpy(id + signer_len + 2, authority, auth_len);
+ id[signer_len + 2 + auth_len] = 0;
+
+ pr_debug("Look up: \"%s\"\n", id);
+
+ key = keyring_search(make_key_ref(keyring, 1),
+ &key_type_asymmetric, id);
+ if (IS_ERR(key))
+ pr_debug("Request for module key '%s' err %ld\n",
+ id, PTR_ERR(key));
+ kfree(id);
+
+ if (IS_ERR(key)) {
+ switch (PTR_ERR(key)) {
+ /* Hide some search errors */
+ case -EACCES:
+ case -ENOTDIR:
+ case -EAGAIN:
+ return ERR_PTR(-ENOKEY);
+ default:
+ return ERR_CAST(key);
+ }
+ }
+
+ pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key_ref_to_ptr(key)));
+ return key_ref_to_ptr(key);
+}
+
+/*
+ * Check the new certificate against the ones in the trust keyring. If one of
+ * those is the signing key and validates the new certificate, then mark the
+ * new certificate as being trusted.
+ *
+ * Return 0 if the new certificate was successfully validated, 1 if we couldn't
+ * find a matching parent certificate in the trusted list and an error if there
+ * is a matching certificate but the signature check fails.
+ */
+static int x509_validate_trust(struct x509_certificate *cert,
+ struct key *trust_keyring)
+{
+ const struct public_key *pk;
+ struct key *key;
+ int ret = 1;
+
+ key = x509_request_asymmetric_key(trust_keyring,
+ cert->issuer, strlen(cert->issuer),
+ cert->authority,
+ strlen(cert->authority));
+ if (!IS_ERR(key)) {
+ pk = key->payload.data;
+ ret = x509_check_signature(pk, cert);
+ }
+ return ret;
+}
+#endif
+
/*
* Attempt to parse a data blob for a key as an X509 certificate.
*/
@@ -155,9 +232,15 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
/* Check the signature on the key if it appears to be self-signed */
if (!cert->authority ||
strcmp(cert->fingerprint, cert->authority) == 0) {
- ret = x509_check_signature(cert->pub, cert);
+ ret = x509_check_signature(cert->pub, cert); /* self-signed */
if (ret < 0)
goto error_free_cert;
+ } else {
+#ifdef CONFIG_SYSTEM_TRUSTED_KEYRING
+ ret = x509_validate_trust(cert, system_trusted_keyring);
+ if (!ret)
+ prep->trusted = 1;
+#endif
}
/* Propose a description */
--
1.8.3.2
next prev parent reply other threads:[~2014-04-23 13:59 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-23 13:30 [PATCH 00/20] in-kernel IMA/EVM initialization Dmitry Kasatkin
2014-04-23 13:30 ` Dmitry Kasatkin [this message]
2014-04-24 16:53 ` [PATCH 01/20] KEYS: verify a certificate is signed by a 'trusted' key Mimi Zohar
2014-04-24 20:07 ` Dmitry Kasatkin
2014-04-24 21:03 ` Mimi Zohar
2014-04-23 13:30 ` [PATCH 02/20] integrity: initialize EVM before IMA Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 03/20] ima: move asymmetric keys config option Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 04/20] integrity: move integrity subsystem options to a separate menu Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 05/20] integrity: provide builtin 'trusted' keyrings Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 06/20] ima: create '_ima' as a builtin 'trusted' keyring Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 07/20] integrity: provide x509 certificate loading from the kernel Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 08/20] ima: load x509 certificate " Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 09/20] evm: create '_evm' as a builtin 'trusted' keyring Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 10/20] evm: load x509 certificate from the kernel Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 11/20] ima: added kernel parameter for disabling IMA Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 12/20] ima: provide buffer hash calculation function Dmitry Kasatkin
2014-04-24 21:04 ` Mimi Zohar
2014-04-25 14:52 ` Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 13/20] ima: replace opencount with bitop Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 14/20] ima: check if policy was set at open Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 15/20] ima: path based policy loading interface Dmitry Kasatkin
2014-04-24 21:03 ` Mimi Zohar
2014-04-25 15:18 ` Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 16/20] ima: load policy from the kernel Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 17/20] ima: make IMA policy replaceable at runtime Dmitry Kasatkin
2014-05-14 23:45 ` Mimi Zohar
2014-05-15 6:08 ` Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 18/20] evm: added kernel parameter for disabling EVM Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 19/20] evm: try enable EVM from the kernel Dmitry Kasatkin
2014-04-23 13:30 ` [PATCH 20/20] evm: read EVM key " Dmitry Kasatkin
2014-04-24 18:44 ` [PATCH 00/20] in-kernel IMA/EVM initialization Mimi Zohar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=0f7915604c69374f15cbaf36c499a5d88264e89d.1398259638.git.d.kasatkin@samsung.com \
--to=d.kasatkin@samsung.com \
--cc=dhowells@redhat.com \
--cc=jmorris@namei.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=roberto.sassu@polito.it \
--cc=zohar@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).