--- /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 (at your option) 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <ipxe/refcnt.h>
+#include <ipxe/malloc.h>
+#include <ipxe/interface.h>
+#include <ipxe/xfer.h>
+#include <ipxe/open.h>
+#include <ipxe/iobuf.h>
+#include <ipxe/xferbuf.h>
+#include <ipxe/process.h>
+#include <ipxe/x509.h>
+#include <ipxe/settings.h>
+#include <ipxe/dhcp.h>
+#include <ipxe/base64.h>
+#include <ipxe/crc32.h>
+#include <ipxe/ocsp.h>
+#include <ipxe/validator.h>
+
+/** @file
+ *
+ * Certificate validator
+ *
+ */
+
+/** A certificate validator */
+struct validator {
+ /** Reference count */
+ struct refcnt refcnt;
+ /** Job control interface */
+ struct interface job;
+ /** Data transfer interface */
+ struct interface xfer;
+
+ /** Process */
+ struct process process;
+
+ /** X.509 certificate chain */
+ struct x509_chain *chain;
+ /** OCSP check */
+ struct ocsp_check *ocsp;
+ /** Data buffer */
+ struct xfer_buffer buffer;
+ /** Action to take upon completed transfer */
+ int ( * done ) ( struct validator *validator, const void *data,
+ size_t len );
+};
+
+/**
+ * Free certificate validator
+ *
+ * @v refcnt Reference count
+ */
+static void validator_free ( struct refcnt *refcnt ) {
+ struct validator *validator =
+ container_of ( refcnt, struct validator, refcnt );
+
+ DBGC2 ( validator, "VALIDATOR %p freed\n", validator );
+ x509_chain_put ( validator->chain );
+ ocsp_put ( validator->ocsp );
+ xferbuf_done ( &validator->buffer );
+ free ( validator );
+}
+
+/**
+ * Mark certificate validation as finished
+ *
+ * @v validator Certificate validator
+ * @v rc Reason for finishing
+ */
+static void validator_finished ( struct validator *validator, int rc ) {
+
+ /* Remove process */
+ process_del ( &validator->process );
+
+ /* Close all interfaces */
+ intf_shutdown ( &validator->xfer, rc );
+ intf_shutdown ( &validator->job, rc );
+}
+
+/****************************************************************************
+ *
+ * Job control interface
+ *
+ */
+
+/** Certificate validator job control interface operations */
+static struct interface_operation validator_job_operations[] = {
+ INTF_OP ( intf_close, struct validator *, validator_finished ),
+};
+
+/** Certificate validator job control interface descriptor */
+static struct interface_descriptor validator_job_desc =
+ INTF_DESC ( struct validator, job, validator_job_operations );
+
+/****************************************************************************
+ *
+ * Cross-signing certificates
+ *
+ */
+
+/** Cross-signed certificate source setting */
+const struct setting crosscert_setting __setting ( SETTING_CRYPTO, crosscert )={
+ .name = "crosscert",
+ .description = "Cross-signed certificate source",
+ .tag = DHCP_EB_CROSS_CERT,
+ .type = &setting_type_string,
+};
+
+/** Default cross-signed certificate source */
+static const char crosscert_default[] = "http://ca.ipxe.org/auto";
+
+/**
+ * Append cross-signing certificates to certificate chain
+ *
+ * @v validator Certificate validator
+ * @v data Raw cross-signing certificate data
+ * @v len Length of raw data
+ * @ret rc Return status code
+ */
+static int validator_append ( struct validator *validator,
+ const void *data, size_t len ) {
+ struct asn1_cursor cursor;
+ struct x509_chain *certs;
+ struct x509_certificate *cert;
+ struct x509_certificate *last;
+ int rc;
+
+ /* Allocate certificate list */
+ certs = x509_alloc_chain();
+ if ( ! certs ) {
+ rc = -ENOMEM;
+ goto err_alloc_certs;
+ }
+
+ /* Initialise cursor */
+ cursor.data = data;
+ cursor.len = len;
+
+ /* Enter certificateSet */
+ if ( ( rc = asn1_enter ( &cursor, ASN1_SET ) ) != 0 ) {
+ DBGC ( validator, "VALIDATOR %p could not enter "
+ "certificateSet: %s\n", validator, strerror ( rc ) );
+ goto err_certificateset;
+ }
+
+ /* Add each certificate to list */
+ while ( cursor.len ) {
+
+ /* Add certificate to chain */
+ if ( ( rc = x509_append_raw ( certs, cursor.data,
+ cursor.len ) ) != 0 ) {
+ DBGC ( validator, "VALIDATOR %p could not append "
+ "certificate: %s\n",
+ validator, strerror ( rc) );
+ DBGC_HDA ( validator, 0, cursor.data, cursor.len );
+ return rc;
+ }
+ cert = x509_last ( certs );
+ DBGC ( validator, "VALIDATOR %p found certificate %s\n",
+ validator, x509_name ( cert ) );
+
+ /* Move to next certificate */
+ asn1_skip_any ( &cursor );
+ }
+
+ /* Append certificates to chain */
+ last = x509_last ( validator->chain );
+ if ( ( rc = x509_auto_append ( validator->chain, certs ) ) != 0 ) {
+ DBGC ( validator, "VALIDATOR %p could not append "
+ "certificates: %s\n", validator, strerror ( rc ) );
+ goto err_auto_append;
+ }
+
+ /* Check that at least one certificate has been added */
+ if ( last == x509_last ( validator->chain ) ) {
+ DBGC ( validator, "VALIDATOR %p failed to append any "
+ "applicable certificates\n", validator );
+ rc = -EACCES;
+ goto err_no_progress;
+ }
+
+ /* Drop reference to certificate list */
+ x509_chain_put ( certs );
+
+ return 0;
+
+ err_no_progress:
+ err_auto_append:
+ err_certificateset:
+ x509_chain_put ( certs );
+ err_alloc_certs:
+ return rc;
+}
+
+/**
+ * Start download of cross-signing certificate
+ *
+ * @v validator Certificate validator
+ * @v issuer Required issuer
+ * @ret rc Return status code
+ */
+static int validator_start_download ( struct validator *validator,
+ const struct asn1_cursor *issuer ) {
+ const char *crosscert;
+ char *crosscert_copy;
+ char *uri_string;
+ size_t uri_string_len;
+ uint32_t crc;
+ int len;
+ int rc;
+
+ /* Determine cross-signed certificate source */
+ fetch_string_setting_copy ( NULL, &crosscert_setting, &crosscert_copy );
+ crosscert = ( crosscert_copy ? crosscert_copy : crosscert_default );
+
+ /* Allocate URI string */
+ uri_string_len = ( strlen ( crosscert ) + 22 /* "/%08x.der?subject=" */
+ + base64_encoded_len ( issuer->len ) + 1 /* NUL */ );
+ uri_string = zalloc ( uri_string_len );
+ if ( ! uri_string ) {
+ rc = -ENOMEM;
+ goto err_alloc_uri_string;
+ }
+
+ /* Generate CRC32 */
+ crc = crc32_le ( 0xffffffffUL, issuer->data, issuer->len );
+
+ /* Generate URI string */
+ len = snprintf ( uri_string, uri_string_len, "%s/%08x.der?subject=",
+ crosscert, crc );
+ base64_encode ( issuer->data, issuer->len, ( uri_string + len ) );
+ DBGC ( validator, "VALIDATOR %p downloading cross-signed certificate "
+ "from %s\n", validator, uri_string );
+
+ /* Set completion handler */
+ validator->done = validator_append;
+
+ /* Open URI */
+ if ( ( rc = xfer_open_uri_string ( &validator->xfer,
+ uri_string ) ) != 0 ) {
+ DBGC ( validator, "VALIDATOR %p could not open %s: %s\n",
+ validator, uri_string, strerror ( rc ) );
+ goto err_open_uri_string;
+ }
+
+ /* Success */
+ rc = 0;
+
+ err_open_uri_string:
+ free ( uri_string );
+ err_alloc_uri_string:
+ free ( crosscert_copy );
+ return rc;
+}
+
+/****************************************************************************
+ *
+ * OCSP checks
+ *
+ */
+
+/**
+ * Validate OCSP response
+ *
+ * @v validator Certificate validator
+ * @v data Raw OCSP response
+ * @v len Length of raw data
+ * @ret rc Return status code
+ */
+static int validator_ocsp_validate ( struct validator *validator,
+ const void *data, size_t len ) {
+ time_t now;
+ int rc;
+
+ /* Record OCSP response */
+ if ( ( rc = ocsp_response ( validator->ocsp, data, len ) ) != 0 ) {
+ DBGC ( validator, "VALIDATOR %p could not record OCSP "
+ "response: %s\n", validator, strerror ( rc ) );
+ return rc;
+ }
+
+ /* Validate OCSP response */
+ now = time ( NULL );
+ if ( ( rc = ocsp_validate ( validator->ocsp, now ) ) != 0 ) {
+ DBGC ( validator, "VALIDATOR %p could not validate OCSP "
+ "response: %s\n", validator, strerror ( rc ) );
+ return rc;
+ }
+
+ /* Drop reference to OCSP check */
+ ocsp_put ( validator->ocsp );
+ validator->ocsp = NULL;
+
+ return 0;
+}
+
+/**
+ * Start OCSP check
+ *
+ * @v validator Certificate validator
+ * @v cert Certificate to check
+ * @v issuer Issuing certificate
+ * @ret rc Return status code
+ */
+static int validator_start_ocsp ( struct validator *validator,
+ struct x509_certificate *cert,
+ struct x509_certificate *issuer ) {
+ const char *uri_string;
+ int rc;
+
+ /* Create OCSP check */
+ assert ( validator->ocsp == NULL );
+ if ( ( rc = ocsp_check ( cert, issuer, &validator->ocsp ) ) != 0 ) {
+ DBGC ( validator, "VALIDATOR %p could not create OCSP check: "
+ "%s\n", validator, strerror ( rc ) );
+ return rc;
+ }
+
+ /* Set completion handler */
+ validator->done = validator_ocsp_validate;
+
+ /* Open URI */
+ uri_string = validator->ocsp->uri_string;
+ DBGC ( validator, "VALIDATOR %p performing OCSP check at %s\n",
+ validator, uri_string );
+ if ( ( rc = xfer_open_uri_string ( &validator->xfer,
+ uri_string ) ) != 0 ) {
+ DBGC ( validator, "VALIDATOR %p could not open %s: %s\n",
+ validator, uri_string, strerror ( rc ) );
+ return rc;
+ }
+
+ return 0;
+}
+
+/****************************************************************************
+ *
+ * Data transfer interface
+ *
+ */
+
+/**
+ * Close data transfer interface
+ *
+ * @v validator Certificate validator
+ * @v rc Reason for close
+ */
+static void validator_xfer_close ( struct validator *validator, int rc ) {
+
+ /* Close data transfer interface */
+ intf_restart ( &validator->xfer, rc );
+
+ /* Check for errors */
+ if ( rc != 0 ) {
+ DBGC ( validator, "VALIDATOR %p transfer failed: %s\n",
+ validator, strerror ( rc ) );
+ goto err_transfer;
+ }
+ DBGC2 ( validator, "VALIDATOR %p transfer complete\n", validator );
+
+ /* Process completed download */
+ assert ( validator->done != NULL );
+ if ( ( rc = validator->done ( validator, validator->buffer.data,
+ validator->buffer.len ) ) != 0 )
+ goto err_append;
+
+ /* Free downloaded data */
+ xferbuf_done ( &validator->buffer );
+
+ /* Resume validation process */
+ process_add ( &validator->process );
+
+ return;
+
+ err_append:
+ err_transfer:
+ validator_finished ( validator, rc );
+}
+
+/**
+ * Receive data
+ *
+ * @v validator Certificate validator
+ * @v iobuf I/O buffer
+ * @v meta Data transfer metadata
+ * @ret rc Return status code
+ */
+static int validator_xfer_deliver ( struct validator *validator,
+ struct io_buffer *iobuf,
+ struct xfer_metadata *meta ) {
+ int rc;
+
+ /* Add data to buffer */
+ if ( ( rc = xferbuf_deliver ( &validator->buffer, iob_disown ( iobuf ),
+ meta ) ) != 0 ) {
+ DBGC ( validator, "VALIDATOR %p could not receive data: %s\n",
+ validator, strerror ( rc ) );
+ validator_finished ( validator, rc );
+ return rc;
+ }
+
+ return 0;
+}
+
+/** Certificate validator data transfer interface operations */
+static struct interface_operation validator_xfer_operations[] = {
+ INTF_OP ( xfer_deliver, struct validator *, validator_xfer_deliver ),
+ INTF_OP ( intf_close, struct validator *, validator_xfer_close ),
+};
+
+/** Certificate validator data transfer interface descriptor */
+static struct interface_descriptor validator_xfer_desc =
+ INTF_DESC ( struct validator, xfer, validator_xfer_operations );
+
+/****************************************************************************
+ *
+ * Validation process
+ *
+ */
+
+/**
+ * Certificate validation process
+ *
+ * @v validator Certificate validator
+ */
+static void validator_step ( struct validator *validator ) {
+ struct x509_link *link;
+ struct x509_certificate *cert;
+ struct x509_certificate *issuer = NULL;
+ struct x509_certificate *last;
+ time_t now;
+ int rc;
+
+ /* Try validating chain. Try even if the chain is incomplete,
+ * since certificates may already have been validated
+ * previously.
+ */
+ now = time ( NULL );
+ if ( ( rc = x509_validate_chain ( validator->chain, now, NULL,
+ NULL ) ) == 0 ) {
+ validator_finished ( validator, 0 );
+ return;
+ }
+
+ /* If there is a certificate that could be validated using
+ * OCSP, try it.
+ */
+ list_for_each_entry ( link, &validator->chain->links, list ) {
+ cert = issuer;
+ issuer = link->cert;
+ if ( ! cert )
+ continue;
+ if ( ! issuer->valid )
+ continue;
+ /* The issuer is valid, but this certificate is not
+ * yet valid. If OCSP is applicable, start it.
+ */
+ if ( cert->extensions.auth_info.ocsp.uri.len &&
+ ( ! cert->extensions.auth_info.ocsp.good ) ) {
+ /* Start OCSP */
+ if ( ( rc = validator_start_ocsp ( validator, cert,
+ issuer ) ) != 0 ) {
+ validator_finished ( validator, rc );
+ return;
+ }
+ return;
+ }
+ /* Otherwise, this is a permanent failure */
+ validator_finished ( validator, rc );
+ return;
+ }
+
+ /* If chain ends with a self-issued certificate, then there is
+ * nothing more to do.
+ */
+ last = x509_last ( validator->chain );
+ if ( asn1_compare ( &last->issuer.raw, &last->subject.raw ) == 0 ) {
+ validator_finished ( validator, rc );
+ return;
+ }
+
+ /* Otherwise, try to download a suitable cross-signing
+ * certificate.
+ */
+ if ( ( rc = validator_start_download ( validator,
+ &last->issuer.raw ) ) != 0 ) {
+ validator_finished ( validator, rc );
+ return;
+ }
+}
+
+/** Certificate validator process descriptor */
+static struct process_descriptor validator_process_desc =
+ PROC_DESC_ONCE ( struct validator, process, validator_step );
+
+/****************************************************************************
+ *
+ * Instantiator
+ *
+ */
+
+/**
+ * Instantiate a certificate validator
+ *
+ * @v job Job control interface
+ * @v chain X.509 certificate chain
+ * @ret rc Return status code
+ */
+int create_validator ( struct interface *job, struct x509_chain *chain ) {
+ struct validator *validator;
+ int rc;
+
+ /* Sanity check */
+ if ( ! chain ) {
+ rc = -EINVAL;
+ goto err_sanity;
+ }
+
+ /* Allocate and initialise structure */
+ validator = zalloc ( sizeof ( *validator ) );
+ if ( ! validator ) {
+ rc = -ENOMEM;
+ goto err_alloc;
+ }
+ ref_init ( &validator->refcnt, validator_free );
+ intf_init ( &validator->job, &validator_job_desc,
+ &validator->refcnt );
+ intf_init ( &validator->xfer, &validator_xfer_desc,
+ &validator->refcnt );
+ process_init ( &validator->process, &validator_process_desc,
+ &validator->refcnt );
+ validator->chain = x509_chain_get ( chain );
+
+ /* Attach parent interface, mortalise self, and return */
+ intf_plug_plug ( &validator->job, job );
+ ref_put ( &validator->refcnt );
+ DBGC2 ( validator, "VALIDATOR %p validating X509 chain %p\n",
+ validator, validator->chain );
+ return 0;
+
+ validator_finished ( validator, rc );
+ ref_put ( &validator->refcnt );
+ err_alloc:
+ err_sanity:
+ return rc;
+}
Code Review / kvmfornfv.git / blobdiff