diff --git a/src/crypto/cms.c b/src/crypto/cms.c new file mode 100644 index 00000000..1e253afa --- /dev/null +++ b/src/crypto/cms.c @@ -0,0 +1,582 @@ +/* + * Copyright (C) 2012 Michael Brown . + * + * 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 +#include +#include +#include +#include +#include +#include +#include + +/* 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; +} diff --git a/src/include/ipxe/asn1.h b/src/include/ipxe/asn1.h index 393d5dc3..d83308a2 100644 --- a/src/include/ipxe/asn1.h +++ b/src/include/ipxe/asn1.h @@ -152,6 +152,12 @@ struct asn1_cursor { ASN1_OID_SINGLE ( 5 ), ASN1_OID_SINGLE ( 7 ), \ ASN1_OID_SINGLE ( 3 ), ASN1_OID_SINGLE ( 3 ) +/** ASN.1 OID for pkcs-signedData (1.2.840.113549.1.7.2) */ +#define ASN1_OID_SIGNEDDATA \ + ASN1_OID_INITIAL ( 1, 2 ), ASN1_OID_DOUBLE ( 840 ), \ + ASN1_OID_TRIPLE ( 113549 ), ASN1_OID_SINGLE ( 1 ), \ + ASN1_OID_SINGLE ( 7 ), ASN1_OID_SINGLE ( 2 ) + /** Define an ASN.1 cursor containing an OID */ #define ASN1_OID_CURSOR( oid_value ) { \ .data = oid_value, \ diff --git a/src/include/ipxe/cms.h b/src/include/ipxe/cms.h new file mode 100644 index 00000000..f355bf1c --- /dev/null +++ b/src/include/ipxe/cms.h @@ -0,0 +1,50 @@ +#ifndef _IPXE_CMS_H +#define _IPXE_CMS_H + +/** @file + * + * Cryptographic Message Syntax (PKCS #7) + * + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#include +#include +#include +#include +#include + +/** CMS signer information */ +struct cms_signer_info { + /** Issuer name */ + struct asn1_cursor issuer; + /** Serial number */ + struct asn1_cursor serial; + /** Digest algorithm */ + struct digest_algorithm *digest; + /** Public-key algorithm */ + struct pubkey_algorithm *pubkey; + /** Signature */ + const void *signature; + /** Length of signature */ + size_t signature_len; +}; + +/** A CMS signature */ +struct cms_signature { + /** Raw certificate list */ + struct asn1_cursor certificates; + /** Signer information + * + * We currently use only the first signer information block. + */ + struct cms_signer_info info; +}; + +extern int cms_parse ( struct cms_signature *sig, const void *data, + size_t len ); +extern int cms_verify ( struct cms_signature *sig, userptr_t data, size_t len, + const char *name, time_t time, struct x509_root *root ); + +#endif /* _IPXE_CMS_H */ diff --git a/src/include/ipxe/errfile.h b/src/include/ipxe/errfile.h index 4b568840..e0473a17 100644 --- a/src/include/ipxe/errfile.h +++ b/src/include/ipxe/errfile.h @@ -249,6 +249,7 @@ FILE_LICENCE ( GPL2_OR_LATER ); #define ERRFILE_rsa ( ERRFILE_OTHER | 0x00270000 ) #define ERRFILE_linux_entropy ( ERRFILE_OTHER | 0x00280000 ) #define ERRFILE_x509_test ( ERRFILE_OTHER | 0x00290000 ) +#define ERRFILE_cms ( ERRFILE_OTHER | 0x002a0000 ) /** @} */