Merge tag 'keys-pkcs7-20140708' into keys-next

Here's a set of changes that implement a PKCS#7 message parser in the kernel.

The PKCS#7 message parsing will then be used to limit kexec to authenticated
kernels only if so configured.

The changes provide the following facilities:

 (1) Parse an ASN.1 PKCS#7 message and pick out useful bits such as the data
     content and the X.509 certificates used to sign it and all the data
     signatures.

 (2) Verify all the data signatures against the set of X.509 certificates
     available in the message.

 (3) Follow the certificate chains and verify that:

     (a) for every self-signed X.509 certificate, check that it validly signed
     	 itself, and:

     (b) for every non-self-signed certificate, if we have a 'parent'
     	 certificate, the former is validly signed by the latter.

 (4) Look for intersections between the certificate chains and the trusted
     keyring, if any intersections are found, verify that the trusted
     certificates signed the intersection point in the chain.

 (5) For testing purposes, a key type can be made available that will take a
     PKCS#7 message, check that the message is trustworthy, and if so, add its
     data content into the key.

Note that (5) has to be altered to take account of the preparsing patches
already committed to this branch.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/crypto/asymmetric_keys/pkcs7_parser.h b/crypto/asymmetric_keys/pkcs7_parser.h
new file mode 100644
index 000000000000..d25f4d15370f
--- /dev/null
+++ b/crypto/asymmetric_keys/pkcs7_parser.h
@@ -0,0 +1,61 @@
+/* PKCS#7 crypto data parser internal definitions
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/oid_registry.h>
+#include <crypto/pkcs7.h>
+#include "x509_parser.h"
+
+#define kenter(FMT, ...) \
+	pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+	pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
+
+struct pkcs7_signed_info {
+	struct pkcs7_signed_info *next;
+	struct x509_certificate *signer; /* Signing certificate (in msg->certs) */
+	unsigned index;
+	bool trusted;
+
+	/* Message digest - the digest of the Content Data (or NULL) */
+	const void	*msgdigest;
+	unsigned	msgdigest_len;
+
+	/* Authenticated Attribute data (or NULL) */
+	unsigned	authattrs_len;
+	const void	*authattrs;
+
+	/* Issuing cert serial number and issuer's name */
+	const void	*raw_serial;
+	unsigned	raw_serial_size;
+	unsigned	raw_issuer_size;
+	const void	*raw_issuer;
+
+	/* Message signature.
+	 *
+	 * This contains the generated digest of _either_ the Content Data or
+	 * the Authenticated Attributes [RFC2315 9.3].  If the latter, one of
+	 * the attributes contains the digest of the the Content Data within
+	 * it.
+	 */
+	struct public_key_signature sig;
+};
+
+struct pkcs7_message {
+	struct x509_certificate *certs;	/* Certificate list */
+	struct x509_certificate *crl;	/* Revocation list */
+	struct pkcs7_signed_info *signed_infos;
+
+	/* Content Data (or NULL) */
+	enum OID	data_type;	/* Type of Data */
+	size_t		data_len;	/* Length of Data */
+	size_t		data_hdrlen;	/* Length of Data ASN.1 header */
+	const void	*data;		/* Content Data (or 0) */
+};