--- /dev/null
+/*
+ * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** @file
+ *
+ * Cryptographic Message Syntax (PKCS #7)
+ *
+ * The format of CMS messages is defined in RFC 5652.
+ *
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include <time.h>
+#include <errno.h>
+#include <ipxe/asn1.h>
+#include <ipxe/x509.h>
+#include <ipxe/uaccess.h>
+#include <ipxe/cms.h>
+
+/* Disambiguate the various error causes */
+#define EACCES_NON_SIGNING \
+ __einfo_error ( EINFO_EACCES_NON_SIGNING )
+#define EINFO_EACCES_NON_SIGNING \
+ __einfo_uniqify ( EINFO_EACCES, 0x01, "Not a signing certificate" )
+#define EACCES_NON_CODE_SIGNING \
+ __einfo_error ( EINFO_EACCES_NON_CODE_SIGNING )
+#define EINFO_EACCES_NON_CODE_SIGNING \
+ __einfo_uniqify ( EINFO_EACCES, 0x02, "Not a code-signing certificate" )
+#define EACCES_INCOMPLETE \
+ __einfo_error ( EINFO_EACCES_INCOMPLETE )
+#define EINFO_EACCES_INCOMPLETE \
+ __einfo_uniqify ( EINFO_EACCES, 0x03, "Incomplete certificate chain" )
+#define EACCES_WRONG_NAME \
+ __einfo_error ( EINFO_EACCES_WRONG_NAME )
+#define EINFO_EACCES_WRONG_NAME \
+ __einfo_uniqify ( EINFO_EACCES, 0x04, "Incorrect certificate name" )
+
+/** "pkcs7-signedData" object identifier */
+static uint8_t oid_signeddata[] = { ASN1_OID_SIGNEDDATA };
+
+/** "pkcs7-signedData" object identifier cursor */
+static struct asn1_cursor oid_signeddata_cursor =
+ ASN1_OID_CURSOR ( oid_signeddata );
+
+/**
+ * Parse CMS signature content type
+ *
+ * @v sig CMS signature
+ * @v raw ASN.1 cursor
+ * @ret rc Return status code
+ */
+static int cms_parse_content_type ( struct cms_signature *sig,
+ const struct asn1_cursor *raw ) {
+ struct asn1_cursor cursor;
+
+ /* Enter contentType */
+ memcpy ( &cursor, raw, sizeof ( cursor ) );
+ asn1_enter ( &cursor, ASN1_OID );
+
+ /* Check OID is pkcs7-signedData */
+ if ( asn1_compare ( &cursor, &oid_signeddata_cursor ) != 0 ) {
+ DBGC ( sig, "CMS %p does not contain signedData:\n", sig );
+ DBGC_HDA ( sig, 0, raw->data, raw->len );
+ return -ENOTSUP;
+ }
+
+ DBGC ( sig, "CMS %p contains signedData\n", sig );
+ return 0;
+}
+
+/**
+ * Parse CMS signature signer identifier
+ *
+ * @v sig CMS signature
+ * @v info Signer information to fill in
+ * @v raw ASN.1 cursor
+ * @ret rc Return status code
+ */
+static int cms_parse_signer_identifier ( struct cms_signature *sig,
+ struct cms_signer_info *info,
+ const struct asn1_cursor *raw ) {
+ struct asn1_cursor cursor;
+ int rc;
+
+ /* Enter issuerAndSerialNumber */
+ memcpy ( &cursor, raw, sizeof ( cursor ) );
+ asn1_enter ( &cursor, ASN1_SEQUENCE );
+
+ /* Record issuer */
+ memcpy ( &info->issuer, &cursor, sizeof ( info->issuer ) );
+ if ( ( rc = asn1_shrink ( &info->issuer, ASN1_SEQUENCE ) ) != 0 ) {
+ DBGC ( sig, "CMS %p/%p could not locate issuer: %s\n",
+ sig, info, strerror ( rc ) );
+ DBGC_HDA ( sig, 0, raw->data, raw->len );
+ return rc;
+ }
+ DBGC ( sig, "CMS %p/%p issuer is:\n", sig, info );
+ DBGC_HDA ( sig, 0, info->issuer.data, info->issuer.len );
+ asn1_skip_any ( &cursor );
+
+ /* Record serialNumber */
+ memcpy ( &info->serial, &cursor, sizeof ( info->serial ) );
+ if ( ( rc = asn1_shrink ( &info->serial, ASN1_INTEGER ) ) != 0 ) {
+ DBGC ( sig, "CMS %p/%p could not locate serialNumber: %s\n",
+ sig, info, strerror ( rc ) );
+ DBGC_HDA ( sig, 0, raw->data, raw->len );
+ return rc;
+ }
+ DBGC ( sig, "CMS %p/%p serial number is:\n", sig, info );
+ DBGC_HDA ( sig, 0, info->serial.data, info->serial.len );
+
+ return 0;
+}
+
+/**
+ * Parse CMS signature digest algorithm
+ *
+ * @v sig CMS signature
+ * @v info Signer information to fill in
+ * @v raw ASN.1 cursor
+ * @ret rc Return status code
+ */
+static int cms_parse_digest_algorithm ( struct cms_signature *sig,
+ struct cms_signer_info *info,
+ const struct asn1_cursor *raw ) {
+ struct asn1_algorithm *algorithm;
+
+ /* Identify algorithm */
+ algorithm = asn1_algorithm ( raw );
+ if ( ! algorithm ) {
+ DBGC ( sig, "CMS %p/%p could not identify digest algorithm:\n",
+ sig, info );
+ DBGC_HDA ( sig, 0, raw->data, raw->len );
+ return -ENOTSUP;
+ }
+
+ /* Check algorithm is a digest algorithm */
+ if ( ! algorithm->digest ) {
+ DBGC ( sig, "CMS %p/%p algorithm %s is not a digest "
+ "algorithm\n", sig, info, algorithm->name );
+ return -EINVAL;
+ }
+
+ /* Record digest algorithm */
+ info->digest = algorithm->digest;
+ DBGC ( sig, "CMS %p/%p digest algorithm is %s\n",
+ sig, info, algorithm->name );
+
+ return 0;
+}
+
+/**
+ * Parse CMS signature algorithm
+ *
+ * @v sig CMS signature
+ * @v info Signer information to fill in
+ * @v raw ASN.1 cursor
+ * @ret rc Return status code
+ */
+static int cms_parse_signature_algorithm ( struct cms_signature *sig,
+ struct cms_signer_info *info,
+ const struct asn1_cursor *raw ) {
+ struct asn1_algorithm *algorithm;
+
+ /* Identify algorithm */
+ algorithm = asn1_algorithm ( raw );
+ if ( ! algorithm ) {
+ DBGC ( sig, "CMS %p/%p could not identify public-key "
+ "algorithm:\n", sig, info );
+ DBGC_HDA ( sig, 0, raw->data, raw->len );
+ return -ENOTSUP;
+ }
+
+ /* Check algorithm is a signature algorithm */
+ if ( ! algorithm->pubkey ) {
+ DBGC ( sig, "CMS %p/%p algorithm %s is not a public-key "
+ "algorithm\n", sig, info, algorithm->name );
+ return -EINVAL;
+ }
+
+ /* Record signature algorithm */
+ info->pubkey = algorithm->pubkey;
+ DBGC ( sig, "CMS %p/%p public-key algorithm is %s\n",
+ sig, info, algorithm->name );
+
+ return 0;
+}
+
+/**
+ * Parse CMS signature value
+ *
+ * @v sig CMS signature
+ * @v info Signer information to fill in
+ * @v raw ASN.1 cursor
+ * @ret rc Return status code
+ */
+static int cms_parse_signature_value ( struct cms_signature *sig,
+ struct cms_signer_info *info,
+ const struct asn1_cursor *raw ) {
+ struct asn1_cursor cursor;
+ int rc;
+
+ /* Enter signature */
+ memcpy ( &cursor, raw, sizeof ( cursor ) );
+ if ( ( rc = asn1_enter ( &cursor, ASN1_OCTET_STRING ) ) != 0 ) {
+ DBGC ( sig, "CMS %p/%p could not locate signature:\n",
+ sig, info );
+ DBGC_HDA ( sig, 0, raw->data, raw->len );
+ return rc;
+ }
+
+ /* Record signature */
+ info->signature = cursor.data;
+ info->signature_len = cursor.len;
+ DBGC ( sig, "CMS %p/%p signature value is:\n", sig, info );
+ DBGC_HDA ( sig, 0, info->signature, info->signature_len );
+
+ return 0;
+}
+
+/**
+ * Parse CMS signature signer information
+ *
+ * @v sig CMS signature
+ * @v info Signer information to fill in
+ * @v raw ASN.1 cursor
+ * @ret rc Return status code
+ */
+static int cms_parse_signer_info ( struct cms_signature *sig,
+ struct cms_signer_info *info,
+ const struct asn1_cursor *raw ) {
+ struct asn1_cursor cursor;
+ int rc;
+
+ /* Enter signerInfo */
+ memcpy ( &cursor, raw, sizeof ( cursor ) );
+ asn1_enter ( &cursor, ASN1_SEQUENCE );
+
+ /* Skip version */
+ asn1_skip ( &cursor, ASN1_INTEGER );
+
+ /* Parse sid */
+ if ( ( rc = cms_parse_signer_identifier ( sig, info, &cursor ) ) != 0 )
+ return rc;
+ asn1_skip_any ( &cursor );
+
+ /* Parse digestAlgorithm */
+ if ( ( rc = cms_parse_digest_algorithm ( sig, info, &cursor ) ) != 0 )
+ return rc;
+ asn1_skip_any ( &cursor );
+
+ /* Skip signedAttrs, if present */
+ asn1_skip_if_exists ( &cursor, ASN1_EXPLICIT_TAG ( 0 ) );
+
+ /* Parse signatureAlgorithm */
+ if ( ( rc = cms_parse_signature_algorithm ( sig, info, &cursor ) ) != 0)
+ return rc;
+ asn1_skip_any ( &cursor );
+
+ /* Parse signature */
+ if ( ( rc = cms_parse_signature_value ( sig, info, &cursor ) ) != 0 )
+ return rc;
+
+ return 0;
+}
+
+/**
+ * Parse CMS signature from ASN.1 data
+ *
+ * @v sig CMS signature
+ * @v data Raw signature data
+ * @v len Length of raw data
+ * @ret rc Return status code
+ */
+int cms_parse ( struct cms_signature *sig, const void *data, size_t len ) {
+ struct asn1_cursor cursor;
+ int rc;
+
+ /* Initialise signature */
+ memset ( sig, 0, sizeof ( *sig ) );
+ cursor.data = data;
+ cursor.len = len;
+
+ /* Enter contentInfo */
+ asn1_enter ( &cursor, ASN1_SEQUENCE );
+
+ /* Parse contentType */
+ if ( ( rc = cms_parse_content_type ( sig, &cursor ) ) != 0 )
+ return rc;
+ asn1_skip_any ( &cursor );
+
+ /* Enter content */
+ asn1_enter ( &cursor, ASN1_EXPLICIT_TAG ( 0 ) );
+
+ /* Enter signedData */
+ asn1_enter ( &cursor, ASN1_SEQUENCE );
+
+ /* Skip version */
+ asn1_skip ( &cursor, ASN1_INTEGER );
+
+ /* Skip digestAlgorithms */
+ asn1_skip ( &cursor, ASN1_SET );
+
+ /* Skip encapContentInfo */
+ asn1_skip ( &cursor, ASN1_SEQUENCE );
+
+ /* Record certificates */
+ memcpy ( &sig->certificates, &cursor, sizeof ( sig->certificates ) );
+ if ( ( rc = asn1_enter ( &sig->certificates,
+ ASN1_EXPLICIT_TAG ( 0 ) ) ) != 0 ) {
+ DBGC ( sig, "CMS %p could not locate certificates:\n", sig );
+ DBGC_HDA ( sig, 0, data, len );
+ return rc;
+ }
+ asn1_skip_any ( &cursor );
+
+ /* Skip crls, if present */
+ asn1_skip_if_exists ( &cursor, ASN1_EXPLICIT_TAG ( 1 ) );
+
+ /* Enter signerInfos */
+ asn1_enter ( &cursor, ASN1_SET );
+
+ /* Parse first signerInfo */
+ if ( ( rc = cms_parse_signer_info ( sig, &sig->info, &cursor ) ) != 0 )
+ return rc;
+
+ return 0;
+}
+
+/** CMS certificate chain context */
+struct cms_chain_context {
+ /** Signature */
+ struct cms_signature *sig;
+ /** Signer information */
+ struct cms_signer_info *info;
+};
+
+/**
+ * Parse next certificate in chain
+ *
+ * @v cert X.509 certificate to parse
+ * @v previous Previous X.509 certificate, or NULL
+ * @v ctx Chain context
+ * @ret rc Return status code
+ */
+static int cms_parse_next ( struct x509_certificate *cert,
+ const struct x509_certificate *previous,
+ void *ctx ) {
+ struct cms_chain_context *context = ctx;
+ struct cms_signature *sig = context->sig;
+ struct cms_signer_info *info = context->info;
+ struct asn1_cursor cursor;
+ int rc;
+
+ /* Search for relevant certificate */
+ memcpy ( &cursor, &sig->certificates, sizeof ( cursor ) );
+ while ( cursor.len ) {
+
+ /* Parse certificate */
+ if ( ( rc = x509_parse ( cert, cursor.data,
+ cursor.len ) ) != 0 ) {
+ DBGC ( sig, "CMS %p/%p could not parse certificate:\n",
+ sig, info );
+ DBGC_HDA ( sig, 0, cursor.data, cursor.len );
+ return rc;
+ }
+
+ if ( previous == NULL ) {
+ /* First certificate: check issuer and serial
+ * number against signer info
+ */
+ if ( ( asn1_compare ( &info->issuer,
+ &cert->issuer.raw ) == 0 ) &&
+ ( asn1_compare ( &info->serial,
+ &cert->serial.raw ) == 0 ) ) {
+ return 0;
+ }
+ } else {
+ /* Subsequent certificates: check subject
+ * against previous certificate's issuer.
+ */
+ if ( asn1_compare ( &previous->issuer.raw,
+ &cert->subject.raw ) == 0 ) {
+ return 0;
+ }
+ }
+
+ /* Move to next certificate */
+ asn1_skip_any ( &cursor );
+ }
+
+ DBGC ( sig, "CMS %p/%p reached end of certificate chain\n", sig, info );
+ return -EACCES_INCOMPLETE;
+}
+
+/**
+ * Calculate digest of CMS-signed data
+ *
+ * @v sig CMS signature
+ * @v info Signer information
+ * @v data Signed data
+ * @v len Length of signed data
+ * @v out Digest output
+ */
+static void cms_digest ( struct cms_signature *sig,
+ struct cms_signer_info *info,
+ userptr_t data, size_t len, void *out ) {
+ struct digest_algorithm *digest = info->digest;
+ uint8_t ctx[ digest->ctxsize ];
+ uint8_t block[ digest->blocksize ];
+ size_t offset = 0;
+ size_t frag_len;
+
+ /* Initialise digest */
+ digest_init ( digest, ctx );
+
+ /* Process data one block at a time */
+ while ( len ) {
+ frag_len = len;
+ if ( frag_len > sizeof ( block ) )
+ frag_len = sizeof ( block );
+ copy_from_user ( block, data, offset, frag_len );
+ digest_update ( digest, ctx, block, frag_len );
+ offset += frag_len;
+ len -= frag_len;
+ }
+
+ /* Finalise digest */
+ digest_final ( digest, ctx, out );
+
+ DBGC ( sig, "CMS %p/%p digest value:\n", sig, info );
+ DBGC_HDA ( sig, 0, out, digest->digestsize );
+}
+
+/**
+ * Verify digest of CMS-signed data
+ *
+ * @v sig CMS signature
+ * @v info Signer information
+ * @v cert Corresponding certificate
+ * @v data Signed data
+ * @v len Length of signed data
+ * @ret rc Return status code
+ */
+static int cms_verify_digest ( struct cms_signature *sig,
+ struct cms_signer_info *info,
+ struct x509_certificate *cert,
+ userptr_t data, size_t len ) {
+ struct digest_algorithm *digest = info->digest;
+ struct pubkey_algorithm *pubkey = info->pubkey;
+ struct x509_public_key *public_key = &cert->subject.public_key;
+ uint8_t digest_out[ digest->digestsize ];
+ uint8_t ctx[ pubkey->ctxsize ];
+ int rc;
+
+ /* Generate digest */
+ cms_digest ( sig, info, data, len, digest_out );
+
+ /* Initialise public-key algorithm */
+ if ( ( rc = pubkey_init ( pubkey, ctx, public_key->raw.data,
+ public_key->raw.len ) ) != 0 ) {
+ DBGC ( sig, "CMS %p/%p could not initialise public key: %s\n",
+ sig, info, strerror ( rc ) );
+ goto err_init;
+ }
+
+ /* Verify digest */
+ if ( ( rc = pubkey_verify ( pubkey, ctx, digest, digest_out,
+ info->signature,
+ info->signature_len ) ) != 0 ) {
+ DBGC ( sig, "CMS %p/%p signature verification failed: %s\n",
+ sig, info, strerror ( rc ) );
+ return rc;
+ }
+
+ pubkey_final ( pubkey, ctx );
+ err_init:
+ return rc;
+}
+
+/**
+ * Verify CMS signature signer information
+ *
+ * @v sig CMS signature
+ * @v info Signer information
+ * @v data Signed data
+ * @v len Length of signed data
+ * @v name Required common name, or NULL to allow any name
+ * @v time Time at which to validate certificates
+ * @v root Root certificate store, or NULL to use default
+ * @ret rc Return status code
+ */
+static int cms_verify_signer_info ( struct cms_signature *sig,
+ struct cms_signer_info *info,
+ userptr_t data, size_t len,
+ const char *name, time_t time,
+ struct x509_root *root ) {
+ struct cms_chain_context context;
+ struct x509_certificate cert;
+ int rc;
+
+ /* Validate certificate chain */
+ context.sig = sig;
+ context.info = info;
+ if ( ( rc = x509_validate_chain ( cms_parse_next, &context, time, root,
+ &cert ) ) != 0 ) {
+ DBGC ( sig, "CMS %p/%p could not validate chain: %s\n",
+ sig, info, strerror ( rc ) );
+ return rc;
+ }
+
+ /* Check that certificate can create digital signatures */
+ if ( ! ( cert.extensions.usage.bits & X509_DIGITAL_SIGNATURE ) ) {
+ DBGC ( sig, "CMS %p/%p certificate cannot create signatures\n",
+ sig, info );
+ return -EACCES_NON_SIGNING;
+ }
+
+ /* Check that certificate can sign code */
+ if ( ! ( cert.extensions.ext_usage.bits & X509_CODE_SIGNING ) ) {
+ DBGC ( sig, "CMS %p/%p certificate is not code-signing\n",
+ sig, info );
+ return -EACCES_NON_CODE_SIGNING;
+ }
+
+ /* Check certificate name, if applicable */
+ if ( ( name != NULL ) &&
+ ( ( cert.subject.name.len != strlen ( name ) ) ||
+ ( memcmp ( cert.subject.name.data, name,
+ cert.subject.name.len ) != 0 ) ) ) {
+ DBGC ( sig, "CMS %p/%p certificate name incorrect\n",
+ sig, info );
+ return -EACCES_WRONG_NAME;
+ }
+
+ /* Verify digest */
+ if ( ( rc = cms_verify_digest ( sig, info, &cert, data, len ) ) != 0 )
+ return rc;
+
+ return 0;
+}
+
+/**
+ * Verify CMS signature
+ *
+ * @v sig CMS signature
+ * @v data Signed data
+ * @v len Length of signed data
+ * @v name Required common name, or NULL to allow any name
+ * @v time Time at which to validate certificates
+ * @v root Root certificate store, or NULL to use default
+ * @ret rc Return status code
+ */
+int cms_verify ( struct cms_signature *sig, userptr_t data, size_t len,
+ const char *name, time_t time, struct x509_root *root ) {
+ int rc;
+
+ /* Verify using first signerInfo */
+ if ( ( rc = cms_verify_signer_info ( sig, &sig->info, data, len,
+ name, time, root ) ) != 0 )
+ return rc;
+
+ return 0;
+}
projects / thirdparty / ipxe.git / commitdiff
