static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
int ca)
{
int i_ext;
/* If ca is true we must return if this is a valid CA certificate. */
if (ca) return check_ca(x);
/*
* Check the optional key usage field:
* if Key Usage is present, it must be one of digitalSignature
* and/or nonRepudiation (other values are not consistent and shall
* be rejected).
*/
if ((x->ex_flags & EXFLAG_KUSAGE)
&& ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) ||
!(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE))))
return 0;
/* Only time stamp key usage is permitted and it's required. */
if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
return 0;
/* Extended Key Usage MUST be critical */
i_ext = X509_get_ext_by_NID((X509 *) x, NID_ext_key_usage, 0);
if (i_ext >= 0)
{
X509_EXTENSION *ext = X509_get_ext((X509 *) x, i_ext);
if (!X509_EXTENSION_get_critical(ext))
return 0;
}
return 1;
}
/* common S/MIME checks */
static int purpose_smime(const X509 *x, int ca)
{
if (xku_reject(x, XKU_SMIME))
return 0;
if (ca) {
int ca_ret;
ca_ret = check_ca(x);
if (!ca_ret)
return 0;
/* check nsCertType if present */
if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA)
return ca_ret;
else
return 0;
}
if (x->ex_flags & EXFLAG_NSCERT) {
if (x->ex_nscert & NS_SMIME)
return 1;
/* Workaround for some buggy certificates */
if (x->ex_nscert & NS_SSL_CLIENT)
return 2;
return 0;
}
return 1;
}
static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
{
/* Must be a valid CA. Should we really support the "I don't know"
value (2)? */
if(ca) return check_ca(x);
/* leaf certificate is checked in OCSP_verify() */
return 1;
}
int X509_check_ca(X509 *x)
{
if(!(x->ex_flags & EXFLAG_SET)) {
x509v3_cache_extensions(x);
}
return check_ca(x);
}
/* Check SSL CA: common checks for SSL client and server */
static int check_ssl_ca(const X509 *x)
{
int ca_ret;
ca_ret = check_ca(x);
if(!ca_ret) return 0;
/* check nsCertType if present */
if(ca_ret != 5 || x->ex_nscert & NS_SSL_CA) return ca_ret;
else return 0;
}
static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
{
if(ca) {
int ca_ret;
if((ca_ret = check_ca(x)) != 2) return ca_ret;
else return 0;
}
if(ku_reject(x, KU_CRL_SIGN)) return 0;
return 1;
}
int X509_check_ca(X509 *x)
{
if(!(x->ex_flags & EXFLAG_SET)) {
CRYPTO_w_lock(CRYPTO_LOCK_X509);
x509v3_cache_extensions(x);
CRYPTO_w_unlock(CRYPTO_LOCK_X509);
}
return check_ca(x);
}
int X509_check_ca(X509 *x)
{
if (!(x->ex_flags & EXFLAG_SET)) {
CRYPTO_THREAD_write_lock(x->lock);
x509v3_cache_extensions(x);
CRYPTO_THREAD_unlock(x->lock);
}
return check_ca(x);
}
int
easy_pkcs7_sign(const char *content, size_t len,
char **signature, size_t *signature_len,
const char *key_file, const char *cert_file)
{
FILE *f;
X509 *certificate;
STACK_OF(X509) *c, *cert_chain;
EVP_PKEY *private_key;
char *tmp_sig;
BIO *out, *in;
PKCS7 *p7;
int status;
OpenSSL_add_all_algorithms();
ERR_load_crypto_strings();
status = -1;
private_key = NULL;
cert_chain = NULL;
in = NULL;
c = file_to_certs(cert_file);
if (sk_X509_num(c) != 1) {
warnx("More then one certificate in the certificate file");
goto cleanup;
}
certificate = sk_X509_value(c, 0);
/* Compute ex_kusage */
X509_check_purpose(certificate, -1, 0);
if (check_ca(certificate)) {
warnx("CA keys are not valid for signatures");
goto cleanup;
}
if (certificate->ex_xkusage != pkg_key_usage) {
warnx("Certificate must have CODE SIGNING "
"and EMAIL PROTECTION property");
goto cleanup;
}
if (cert_chain_file)
cert_chain = file_to_certs(cert_chain_file);
if ((f = fopen(key_file, "r")) == NULL) {
warn("Failed to open private key file %s", key_file);
goto cleanup;
}
private_key = PEM_read_PrivateKey(f, NULL, ssl_pass_cb, NULL);
fclose(f);
if (private_key == NULL) {
warnx("Can't read private key: %s", key_file);
goto cleanup;
}
if (X509_check_private_key(certificate, private_key) != 1) {
warnx("The private key %s doesn't match the certificate %s",
key_file, cert_file);
goto cleanup;
}
in = BIO_new_mem_buf(__UNCONST(content), len);
p7 = PKCS7_sign(certificate, private_key, cert_chain, in,
PKCS7_DETACHED|PKCS7_NOATTR|PKCS7_BINARY);
if (p7 == NULL) {
warnx("Failed to create signature structure");
goto cleanup;
}
out = BIO_new(BIO_s_mem());
PEM_write_bio_PKCS7(out, p7);
*signature_len = BIO_get_mem_data(out, &tmp_sig);
*signature = xmalloc(*signature_len);
memcpy(*signature, tmp_sig, *signature_len);
BIO_free_all(out);
PKCS7_free(p7);
status = 0;
cleanup:
sk_X509_free(c);
sk_X509_free(cert_chain);
EVP_PKEY_free(private_key);
BIO_free(in);
return status;
}
int
easy_pkcs7_verify(const char *content, size_t len,
const char *signature, size_t signature_len,
const char *anchor, int is_pkg)
{
STACK_OF(X509) *cert_chain, *signers;
X509_STORE *store;
BIO *sig, *in;
PKCS7 *p7;
int i, status;
X509_NAME *name;
char *subject;
OpenSSL_add_all_algorithms();
ERR_load_crypto_strings();
status = -1;
if (cert_chain_file)
cert_chain = file_to_certs(cert_chain_file);
else
cert_chain = NULL;
store = X509_STORE_new();
if (store == NULL) {
sk_X509_free(cert_chain);
warnx("Failed to create certificate store");
return -1;
}
X509_STORE_load_locations(store, anchor, NULL);
in = BIO_new_mem_buf(__UNCONST(content), len);
sig = BIO_new_mem_buf(__UNCONST(signature), signature_len);
signers = NULL;
p7 = PEM_read_bio_PKCS7(sig, NULL, NULL, NULL);
if (p7 == NULL) {
warnx("Failed to parse the signature");
goto cleanup;
}
if (PKCS7_verify(p7, cert_chain, store, in, NULL, 0) != 1) {
warnx("Failed to verify signature");
goto cleanup;
}
signers = PKCS7_get0_signers(p7, NULL, 0);
if (signers == NULL) {
warnx("Failed to get signers");
goto cleanup;
}
if (sk_X509_num(signers) == 0) {
warnx("No signers found");
goto cleanup;
}
for (i = 0; i < sk_X509_num(signers); i++) {
/* Compute ex_xkusage */
X509_check_purpose(sk_X509_value(signers, i), -1, -1);
if (check_ca(sk_X509_value(signers, i))) {
warnx("CA keys are not valid for signatures");
goto cleanup;
}
if (is_pkg) {
if (sk_X509_value(signers, i)->ex_xkusage != pkg_key_usage) {
warnx("Certificate must have CODE SIGNING "
"and EMAIL PROTECTION property");
goto cleanup;
}
} else {
if (sk_X509_value(signers, i)->ex_xkusage != 0) {
warnx("Certificate must not have any property");
goto cleanup;
}
}
}
printf("Sigature ok, signed by:\n");
for (i = 0; i < sk_X509_num(signers); i++) {
name = X509_get_subject_name(sk_X509_value(signers, i));
subject = X509_NAME_oneline(name, NULL, 0);
printf("\t%s\n", subject);
OPENSSL_free(subject);
}
status = 0;
cleanup:
sk_X509_free(cert_chain);
sk_X509_free(signers);
X509_STORE_free(store);
PKCS7_free(p7);
BIO_free(in);
BIO_free(sig);
return status;
}
