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[Openvpn-devel] [PATCH] Use CryptoAPI CA store
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From: Faidon L. <par...@de...> - 2006-12-24 21:29:28
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Hello,
Below you will find a patch that creates a new configuration option
--cryptoapicastore (the naming sucks, I know...) which enables certificate
verification using Windows Certificate Stores (CA and ROOT).
It can be used in addition to --cafile and --capath or standalone.
I have compile and briefly runtime tested it and it works as intended.
It should be used with care -and this should probably be noted
somewhere- and preferrably in conjuction with tls-verify or tls-remote
and/or password authentication.
I have a couple of improvements in mind (e.g. optionally filtering by
certificate subject) and the documentation for the manpage is missing,
but I'm posting this early since I will be on vacation for the next
week.
Happy holidays :-)
Best regards,
Faidon
diff -Nur openvpn-2.1_rc1/cryptoapi.c openvpn-2.1_rc1-void/cryptoapi.c
--- openvpn-2.1_rc1/cryptoapi.c 2006-10-16 01:30:21.000000000 +0300
+++ openvpn-2.1_rc1-void/cryptoapi.c 2006-12-22 19:20:34.000000000 +0200
@@ -48,6 +48,8 @@
static HINSTANCE crypt32dll = NULL;
static BOOL WINAPI (*CryptAcquireCertificatePrivateKey) (PCCERT_CONTEXT pCert, DWORD dwFlags,
void *pvReserved, HCRYPTPROV *phCryptProv, DWORD *pdwKeySpec, BOOL *pfCallerFreeProv) = NULL;
+static PCCERT_CONTEXT WINAPI (*CertEnumCertificatesInStore) (HCERTSTORE hCertStore,
+ PCCERT_CONTEXT pPrevCertContext) = NULL;
#endif
/* Size of an SSL signature: MD5+SHA1 */
@@ -364,7 +366,8 @@
}
/* cert_context->pbCertEncoded is the cert X509 DER encoded. */
- cert = d2i_X509(NULL, (unsigned char **) &cd->cert_context->pbCertEncoded,
+ cert = d2i_X509(NULL,
+ (const unsigned char **) &cd->cert_context->pbCertEncoded,
cd->cert_context->cbCertEncoded);
if (cert == NULL) {
SSLerr(SSL_F_SSL_CTX_USE_CERTIFICATE_FILE, ERR_R_ASN1_LIB);
@@ -461,3 +464,57 @@
}
return 0;
}
+
+int SSL_CTX_add_CryptoAPI_certificate_store(SSL_CTX *ssl_ctx, const char *store)
+{
+ HCERTSTORE cs;
+ PCCERT_CONTEXT ctx = NULL;
+ X509 *cert = NULL;
+
+ cs = CertOpenSystemStore(0, store);
+ if (cs == NULL) {
+ CRYPTOAPIerr(CRYPTOAPI_F_CERT_OPEN_SYSTEM_STORE);
+ goto err;
+ }
+
+#ifdef __MINGW32_VERSION
+ /* MinGW w32api is incomplete when it comes to CryptoAPI, as per version 3.1
+ * anyway. This is a hack around that problem. */
+ if (crypt32dll == NULL) {
+ crypt32dll = LoadLibrary("crypt32");
+ if (crypt32dll == NULL) {
+ CRYPTOAPIerr(CRYPTOAPI_F_LOAD_LIBRARY);
+ goto err;
+ }
+ }
+ if (CertEnumCertificatesInStore == NULL) {
+ CertEnumCertificatesInStore = GetProcAddress(crypt32dll,
+ "CertEnumCertificatesInStore");
+ if (CertEnumCertificatesInStore == NULL) {
+ CRYPTOAPIerr(CRYPTOAPI_F_GET_PROC_ADDRESS);
+ goto err;
+ }
+ }
+#endif
+
+ while ((ctx = CertEnumCertificatesInStore(cs, ctx))) {
+ cert = d2i_X509(NULL, (const unsigned char **) &ctx->pbCertEncoded,
+ ctx->cbCertEncoded);
+ if (cert == NULL) {
+ SSLerr(SSL_F_SSL_CTX_USE_CERTIFICATE_FILE, ERR_R_ASN1_LIB);
+ goto err;
+ }
+
+ if (!X509_STORE_add_cert(ssl_ctx->cert_store, cert)) {
+ goto err;
+ }
+ X509_free(cert);
+ }
+ CertCloseStore(cs, 0);
+ return 1;
+
+ err:
+ if (cert)
+ X509_free(cert);
+ return 0;
+}
diff -Nur openvpn-2.1_rc1/cryptoapi.h openvpn-2.1_rc1-void/cryptoapi.h
--- openvpn-2.1_rc1/cryptoapi.h 2006-10-16 01:30:21.000000000 +0300
+++ openvpn-2.1_rc1-void/cryptoapi.h 2006-12-22 05:24:19.000000000 +0200
@@ -2,6 +2,7 @@
#define _CRYPTOAPI_H_
int SSL_CTX_use_CryptoAPI_certificate(SSL_CTX *ssl_ctx, const char *cert_prop);
+int SSL_CTX_add_CryptoAPI_certificate_store(SSL_CTX *ssl_ctx, const char *store);
#endif /* !_CRYPTOAPI_H_ */
diff -Nur openvpn-2.1_rc1/options.c openvpn-2.1_rc1-void/options.c
--- openvpn-2.1_rc1/options.c 2006-10-16 01:30:21.000000000 +0300
+++ openvpn-2.1_rc1-void/options.c 2006-12-22 06:51:37.000000000 +0200
@@ -447,6 +447,7 @@
#ifdef WIN32
"--cryptoapicert select-string : Load the certificate and private key from the\n"
" Windows Certificate System Store.\n"
+ "--cryptoapicastore : Add Windows Certificate Store Certificate Authorities.\n"
#endif
"--tls-cipher l : A list l of allowable TLS ciphers separated by : (optional).\n"
" : Use --show-tls to see a list of supported TLS ciphers.\n"
@@ -1233,6 +1234,7 @@
SHOW_STR (pkcs12_file);
#ifdef WIN32
SHOW_STR (cryptoapi_cert);
+ SHOW_BOOL (cryptoapi_castore);
#endif
SHOW_STR (cipher_list);
SHOW_STR (tls_verify);
@@ -1806,8 +1808,8 @@
#ifdef WIN32
if (options->cryptoapi_cert)
{
- if ((!(options->ca_file)) && (!(options->ca_path)))
- msg(M_USAGE, "You must define CA file (--ca) or CA path (--capath)");
+ if ((!(options->ca_file)) && (!(options->ca_path)) && (!(options->cryptoapi_castore)))
+ msg(M_USAGE, "You must define CA file (--ca) or CA path (--capath) or CryptoAPI CAs (--cryptoapicastore");
if (options->cert_file)
msg(M_USAGE, "Parameter --cert cannot be used when --cryptoapicert is also specified.");
if (options->priv_key_file)
@@ -1828,8 +1830,12 @@
}
else
{
- if ((!(options->ca_file)) && (!(options->ca_path)))
+ if ((!(options->ca_file)) && (!(options->ca_path)) && (!(options->cryptoapi_castore)))
+#ifdef WIN32
+ msg(M_USAGE, "You must define CA file (--ca) or CA path (--capath) or CryptoAPI CAs (--cryptoapicastore");
+#else
msg(M_USAGE, "You must define CA file (--ca) or CA path (--capath)");
+#endif
if (pull)
{
const int sum = (options->cert_file != NULL) + (options->priv_key_file != NULL);
@@ -4886,6 +4892,11 @@
VERIFY_PERMISSION (OPT_P_GENERAL);
options->cryptoapi_cert = p[1];
}
+ else if (streq (p[0], "cryptoapicastore"))
+ {
+ VERIFY_PERMISSION (OPT_P_GENERAL);
+ options->cryptoapi_castore = true;
+ }
#endif
else if (streq (p[0], "key") && p[1])
{
diff -Nur openvpn-2.1_rc1/options.h openvpn-2.1_rc1-void/options.h
--- openvpn-2.1_rc1/options.h 2006-10-16 01:30:21.000000000 +0300
+++ openvpn-2.1_rc1-void/options.h 2006-12-22 06:51:05.000000000 +0200
@@ -424,6 +424,7 @@
#ifdef WIN32
const char *cryptoapi_cert;
+ bool cryptoapi_castore;
#endif
/* data channel key exchange method */
diff -Nur openvpn-2.1_rc1/ssl.c openvpn-2.1_rc1-void/ssl.c
--- openvpn-2.1_rc1/ssl.c 2006-10-16 01:30:21.000000000 +0300
+++ openvpn-2.1_rc1-void/ssl.c 2006-12-22 06:55:45.000000000 +0200
@@ -1276,6 +1276,17 @@
}
}
+#ifdef WIN32
+ if (options->cryptoapi_castore)
+ {
+ /* Add CAs from Windows' certification stores to our store */
+ if (!SSL_CTX_add_CryptoAPI_certificate_store(ctx, "CA"))
+ msg (M_SSLERR, "Cannot load CA certificates from Microsoft Certificate Store");
+ if (!SSL_CTX_add_CryptoAPI_certificate_store(ctx, "ROOT"))
+ msg (M_SSLERR, "Cannot load Root certificates from Microsoft Certificate Store");
+ }
+#endif
+
/* Enable the use of certificate chains */
if (using_cert_file)
{
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