crypto/cms: Add support for CAdES Basic Electronic Signatures (CAdES-BES)

A CAdES Basic Electronic Signature (CAdES-BES) contains, among other
specifications, a collection of  Signing Certificate reference attributes,
stored in the signedData ether as ESS signing-certificate or as
ESS signing-certificate-v2. These are described in detail in Section 5.7.2
of RFC 5126 - CMS Advanced Electronic Signatures (CAdES).

This patch adds support for adding  ESS signing-certificate[-v2] attributes
to CMS signedData. Although it implements only a small part of the RFC, it
is sufficient many cases to enable the `openssl cms` app to create signatures
which comply with legal requirements of some European States (e.g Italy).

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/7893)

1 files changed, 269 insertions, 0 deletions

diff --git a/crypto/ess/ess_lib.c b/crypto/ess/ess_lib.c
new file mode 100644
index 0000000..fa9cff1
--- /dev/null
+++ b/crypto/ess/ess_lib.c
@@ -0,0 +1,269 @@
+/*
+ * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <string.h>
+#include <openssl/x509v3.h>
+#include <openssl/err.h>
+#include <openssl/ess.h>
+#include "internal/ess_int.h"
+
+static ESS_CERT_ID *ESS_CERT_ID_new_init(X509 *cert, int issuer_needed);
+static ESS_CERT_ID_V2 *ESS_CERT_ID_V2_new_init(const EVP_MD *hash_alg,
+                                               X509 *cert, int issuer_needed);
+
+ESS_SIGNING_CERT *ESS_SIGNING_CERT_new_init(X509 *signcert,
+                                            STACK_OF(X509) *certs,
+                                            int issuer_needed)
+{
+    ESS_CERT_ID *cid = NULL;
+    ESS_SIGNING_CERT *sc;
+    int i;
+
+    if ((sc = ESS_SIGNING_CERT_new()) == NULL)
+        goto err;
+    if (sc->cert_ids == NULL
+        && (sc->cert_ids = sk_ESS_CERT_ID_new_null()) == NULL)
+        goto err;
+
+    if ((cid = ESS_CERT_ID_new_init(signcert, issuer_needed)) == NULL
+        || !sk_ESS_CERT_ID_push(sc->cert_ids, cid))
+        goto err;
+    for (i = 0; i < sk_X509_num(certs); ++i) {
+        X509 *cert = sk_X509_value(certs, i);
+        if ((cid = ESS_CERT_ID_new_init(cert, 1)) == NULL
+            || !sk_ESS_CERT_ID_push(sc->cert_ids, cid))
+            goto err;
+    }
+
+    return sc;
+ err:
+    ESS_SIGNING_CERT_free(sc);
+    ESS_CERT_ID_free(cid);
+    ESSerr(ESS_F_ESS_SIGNING_CERT_NEW_INIT, ERR_R_MALLOC_FAILURE);
+    return NULL;
+}
+
+static ESS_CERT_ID *ESS_CERT_ID_new_init(X509 *cert, int issuer_needed)
+{
+    ESS_CERT_ID *cid = NULL;
+    GENERAL_NAME *name = NULL;
+    unsigned char cert_sha1[SHA_DIGEST_LENGTH];
+
+    /* Call for side-effect of computing hash and caching extensions */
+    X509_check_purpose(cert, -1, 0);
+    if ((cid = ESS_CERT_ID_new()) == NULL)
+        goto err;
+    X509_digest(cert, EVP_sha1(), cert_sha1, NULL);
+    if (!ASN1_OCTET_STRING_set(cid->hash, cert_sha1, SHA_DIGEST_LENGTH))
+        goto err;
+
+    /* Setting the issuer/serial if requested. */
+    if (!issuer_needed)
+        return cid;
+
+    if (cid->issuer_serial == NULL
+        && (cid->issuer_serial = ESS_ISSUER_SERIAL_new()) == NULL)
+        goto err;
+    if ((name = GENERAL_NAME_new()) == NULL)
+        goto err;
+    name->type = GEN_DIRNAME;
+    if ((name->d.dirn = X509_NAME_dup(X509_get_issuer_name(cert))) == NULL)
+        goto err;
+    if (!sk_GENERAL_NAME_push(cid->issuer_serial->issuer, name))
+        goto err;
+    name = NULL;            /* Ownership is lost. */
+    ASN1_INTEGER_free(cid->issuer_serial->serial);
+    if (!(cid->issuer_serial->serial =
+          ASN1_INTEGER_dup(X509_get_serialNumber(cert))))
+        goto err;
+
+    return cid;
+ err:
+    GENERAL_NAME_free(name);
+    ESS_CERT_ID_free(cid);
+    ESSerr(ESS_F_ESS_CERT_ID_NEW_INIT, ERR_R_MALLOC_FAILURE);
+    return NULL;
+}
+
+ESS_SIGNING_CERT_V2 *ESS_SIGNING_CERT_V2_new_init(const EVP_MD *hash_alg,
+                                                  X509 *signcert,
+                                                  STACK_OF(X509) *certs,
+                                                  int issuer_needed)
+{
+    ESS_CERT_ID_V2 *cid = NULL;
+    ESS_SIGNING_CERT_V2 *sc;
+    int i;
+
+    if ((sc = ESS_SIGNING_CERT_V2_new()) == NULL)
+        goto err;
+    if ((cid = ESS_CERT_ID_V2_new_init(hash_alg, signcert, issuer_needed)) == NULL)
+        goto err;
+    if (!sk_ESS_CERT_ID_V2_push(sc->cert_ids, cid))
+        goto err;
+    cid = NULL;
+
+    for (i = 0; i < sk_X509_num(certs); ++i) {
+        X509 *cert = sk_X509_value(certs, i);
+
+        if ((cid = ESS_CERT_ID_V2_new_init(hash_alg, cert, 1)) == NULL)
+            goto err;
+        if (!sk_ESS_CERT_ID_V2_push(sc->cert_ids, cid))
+            goto err;
+        cid = NULL;
+    }
+
+    return sc;
+ err:
+    ESS_SIGNING_CERT_V2_free(sc);
+    ESS_CERT_ID_V2_free(cid);
+    ESSerr(ESS_F_ESS_SIGNING_CERT_V2_NEW_INIT, ERR_R_MALLOC_FAILURE);
+    return NULL;
+}
+
+static ESS_CERT_ID_V2 *ESS_CERT_ID_V2_new_init(const EVP_MD *hash_alg,
+                                               X509 *cert, int issuer_needed)
+{
+    ESS_CERT_ID_V2 *cid;
+    GENERAL_NAME *name = NULL;
+    unsigned char hash[EVP_MAX_MD_SIZE];
+    unsigned int hash_len = sizeof(hash);
+    X509_ALGOR *alg = NULL;
+
+    memset(hash, 0, sizeof(hash));
+
+    if ((cid = ESS_CERT_ID_V2_new()) == NULL)
+        goto err;
+
+    if (hash_alg != EVP_sha256()) {
+        alg = X509_ALGOR_new();
+        if (alg == NULL)
+            goto err;
+        X509_ALGOR_set_md(alg, hash_alg);
+        if (alg->algorithm == NULL)
+            goto err;
+        cid->hash_alg = alg;
+        alg = NULL;
+    } else {
+        cid->hash_alg = NULL;
+    }
+
+    if (!X509_digest(cert, hash_alg, hash, &hash_len))
+        goto err;
+
+    if (!ASN1_OCTET_STRING_set(cid->hash, hash, hash_len))
+        goto err;
+
+    if (!issuer_needed)
+        return cid;
+
+    if ((cid->issuer_serial = ESS_ISSUER_SERIAL_new()) == NULL)
+        goto err;
+    if ((name = GENERAL_NAME_new()) == NULL)
+        goto err;
+    name->type = GEN_DIRNAME;
+    if ((name->d.dirn = X509_NAME_dup(X509_get_issuer_name(cert))) == NULL)
+        goto err;
+    if (!sk_GENERAL_NAME_push(cid->issuer_serial->issuer, name))
+        goto err;
+    name = NULL;            /* Ownership is lost. */
+    ASN1_INTEGER_free(cid->issuer_serial->serial);
+    cid->issuer_serial->serial = ASN1_INTEGER_dup(X509_get_serialNumber(cert));
+    if (cid->issuer_serial->serial == NULL)
+        goto err;
+
+    return cid;
+ err:
+    X509_ALGOR_free(alg);
+    GENERAL_NAME_free(name);
+    ESS_CERT_ID_V2_free(cid);
+    ESSerr(ESS_F_ESS_CERT_ID_V2_NEW_INIT, ERR_R_MALLOC_FAILURE);
+    return NULL;
+}
+
+ESS_SIGNING_CERT *ESS_SIGNING_CERT_get(PKCS7_SIGNER_INFO *si)
+{
+    ASN1_TYPE *attr;
+    const unsigned char *p;
+    attr = PKCS7_get_signed_attribute(si, NID_id_smime_aa_signingCertificate);
+    if (!attr)
+        return NULL;
+    p = attr->value.sequence->data;
+    return d2i_ESS_SIGNING_CERT(NULL, &p, attr->value.sequence->length);
+}
+
+ESS_SIGNING_CERT_V2 *ESS_SIGNING_CERT_V2_get(PKCS7_SIGNER_INFO *si)
+{
+    ASN1_TYPE *attr;
+    const unsigned char *p;
+
+    attr = PKCS7_get_signed_attribute(si, NID_id_smime_aa_signingCertificateV2);
+    if (attr == NULL)
+        return NULL;
+    p = attr->value.sequence->data;
+    return d2i_ESS_SIGNING_CERT_V2(NULL, &p, attr->value.sequence->length);
+}
+
+int ESS_SIGNING_CERT_add(PKCS7_SIGNER_INFO *si, ESS_SIGNING_CERT *sc)
+{
+    ASN1_STRING *seq = NULL;
+    unsigned char *p, *pp = NULL;
+    int len;
+
+    len = i2d_ESS_SIGNING_CERT(sc, NULL);
+    if ((pp = OPENSSL_malloc(len)) == NULL) {
+        ESSerr(ESS_F_ESS_SIGNING_CERT_ADD, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+    p = pp;
+    i2d_ESS_SIGNING_CERT(sc, &p);
+    if ((seq = ASN1_STRING_new()) == NULL || !ASN1_STRING_set(seq, pp, len)) {
+        ESSerr(ESS_F_ESS_SIGNING_CERT_ADD, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+    OPENSSL_free(pp);
+    pp = NULL;
+    return PKCS7_add_signed_attribute(si,
+                                      NID_id_smime_aa_signingCertificate,
+                                      V_ASN1_SEQUENCE, seq);
+ err:
+    ASN1_STRING_free(seq);
+    OPENSSL_free(pp);
+
+    return 0;
+}
+
+int ESS_SIGNING_CERT_V2_add(PKCS7_SIGNER_INFO *si,
+                            ESS_SIGNING_CERT_V2 *sc)
+{
+    ASN1_STRING *seq = NULL;
+    unsigned char *p, *pp = NULL;
+    int len = i2d_ESS_SIGNING_CERT_V2(sc, NULL);
+
+    if ((pp = OPENSSL_malloc(len)) == NULL) {
+        ESSerr(ESS_F_ESS_SIGNING_CERT_V2_ADD, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    p = pp;
+    i2d_ESS_SIGNING_CERT_V2(sc, &p);
+    if ((seq = ASN1_STRING_new()) == NULL || !ASN1_STRING_set(seq, pp, len)) {
+        ESSerr(ESS_F_ESS_SIGNING_CERT_V2_ADD, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    OPENSSL_free(pp);
+    pp = NULL;
+    return PKCS7_add_signed_attribute(si,
+                                      NID_id_smime_aa_signingCertificateV2,
+                                      V_ASN1_SEQUENCE, seq);
+ err:
+    ASN1_STRING_free(seq);
+    OPENSSL_free(pp);
+    return 0;
+}