Here's a set of patches that implements 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 patches 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. They can be found on this branch also: http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-modsign.git/log/?h=pkcs7 and are tagged with: keys-pkcs7-20140708 David --- David Howells (7): X.509: Export certificate parse and free functions PKCS#7: Implement a parser [RFC 2315] PKCS#7: Digest the data in a signed-data message PKCS#7: Find the right key in the PKCS#7 key list and verify the signature PKCS#7: Verify internal certificate chain PKCS#7: Find intersection between PKCS#7 message and known, trusted keys PKCS#7: Provide a key type for testing PKCS#7 crypto/asymmetric_keys/Kconfig | 22 ++ crypto/asymmetric_keys/Makefile | 22 ++ crypto/asymmetric_keys/pkcs7.asn1 | 127 +++++++++ crypto/asymmetric_keys/pkcs7_key_type.c | 97 +++++++ crypto/asymmetric_keys/pkcs7_parser.c | 396 +++++++++++++++++++++++++++++ crypto/asymmetric_keys/pkcs7_parser.h | 61 ++++ crypto/asymmetric_keys/pkcs7_trust.c | 219 ++++++++++++++++ crypto/asymmetric_keys/pkcs7_verify.c | 323 ++++++++++++++++++++++++ crypto/asymmetric_keys/x509_cert_parser.c | 3 include/crypto/pkcs7.h | 36 +++ include/linux/oid_registry.h | 1 11 files changed, 1307 insertions(+) create mode 100644 crypto/asymmetric_keys/pkcs7.asn1 create mode 100644 crypto/asymmetric_keys/pkcs7_key_type.c create mode 100644 crypto/asymmetric_keys/pkcs7_parser.c create mode 100644 crypto/asymmetric_keys/pkcs7_parser.h create mode 100644 crypto/asymmetric_keys/pkcs7_trust.c create mode 100644 crypto/asymmetric_keys/pkcs7_verify.c create mode 100644 include/crypto/pkcs7.h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/