openssl: add support for the Certificate Status Request TLS extension (d1cf5d57) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP curl

docs/libcurl/opts/CURLOPT_SSL_VERIFYSTATUS.3

+2 −2

Original line number	Diff line number	Diff line
		@@ -42,8 +42,8 @@ All TLS based protocols: HTTPS, FTPS, IMAPS, POP3, SMTPS etc.
		.SH EXAMPLE
		TODO
		.SH AVAILABILITY
		Added in 7.41.0. This option is currently only supported by the GnuTLS and NSS
		TLS backends.
		Added in 7.41.0. This option is currently only supported by the OpenSSL, GnuTLS
		and NSS TLS backends.
		.SH RETURN VALUE
		Returns CURLE_OK if OCSP stapling is supported by the SSL backend, otherwise
		returns CURLE_NOT_BUILT_IN.

lib/vtls/openssl.c

+143 −0

Original line number	Diff line number	Diff line
		@@ -64,6 +64,7 @@
		#include <openssl/md5.h>
		#include <openssl/conf.h>
		#include <openssl/bn.h>
		#include <openssl/ocsp.h>
		#else
		#include <rand.h>
		#include <x509v3.h>
		@@ -1319,6 +1320,130 @@ static CURLcode verifyhost(struct connectdata conn, X509 server_cert)

		return result;
		}

		static CURLcode verifystatus(struct connectdata *conn,
		struct ssl_connect_data *connssl)
		{
		int i, ocsp_status;
		const unsigned char *p;
		CURLcode result = CURLE_OK;
		struct SessionHandle *data = conn->data;

		OCSP_RESPONSE *rsp = NULL;
		OCSP_BASICRESP *br = NULL;
		X509_STORE *st = NULL;
		STACK_OF(X509) *ch = NULL;

		long len = SSL_get_tlsext_status_ocsp_resp(connssl->handle, &p);

		if(!p) {
		failf(data, "No OCSP response received");
		result = CURLE_SSL_INVALIDCERTSTATUS;
		goto end;
		}

		rsp = d2i_OCSP_RESPONSE(NULL, &p, len);
		if(!rsp) {
		failf(data, "Invalid OCSP response");
		result = CURLE_SSL_INVALIDCERTSTATUS;
		goto end;
		}

		ocsp_status = OCSP_response_status(rsp);
		if(ocsp_status != OCSP_RESPONSE_STATUS_SUCCESSFUL) {
		failf(data, "Invalid OCSP response status: %s (%d)",
		OCSP_response_status_str(ocsp_status), ocsp_status);
		result = CURLE_SSL_INVALIDCERTSTATUS;
		goto end;
		}

		br = OCSP_response_get1_basic(rsp);
		if(!br) {
		failf(data, "Invalid OCSP response");
		result = CURLE_SSL_INVALIDCERTSTATUS;
		goto end;
		}

		ch = SSL_get_peer_cert_chain(connssl->handle);
		st = SSL_CTX_get_cert_store(connssl->ctx);

		/* The authorized responder cert in the OCSP response MUST be signed by the
		peer cert's issuer (see RFC6960 section 4.2.2.2). If that's a root cert,
		no problem, but if it's an intermediate cert OpenSSL has a bug where it
		expects this issuer to be present in the chain embedded in the OCSP
		response. So we add it if necessary. */

		/* First make sure the peer cert chain includes both a peer and an issuer,
		and the OCSP response contains a responder cert. */
		if(sk_X509_num(ch) >= 2 && sk_X509_num(br->certs) >= 1) {
		X509 *responder = sk_X509_value(br->certs, sk_X509_num(br->certs) - 1);

		/* Find issuer of responder cert and add it to the OCSP response chain */
		for(i = 0; i < sk_X509_num(ch); i++) {
		X509 *issuer = sk_X509_value(ch, i);
		if(X509_check_issued(issuer, responder) == X509_V_OK) {
		if(!OCSP_basic_add1_cert(br, issuer)) {
		failf(data, "Could not add issuer cert to OCSP response");
		result = CURLE_SSL_INVALIDCERTSTATUS;
		goto end;
		}
		}
		}
		}

		if(OCSP_basic_verify(br, ch, st, 0) <= 0) {
		failf(data, "OCSP response verification failed");
		result = CURLE_SSL_INVALIDCERTSTATUS;
		goto end;
		}

		for(i = 0; i < sk_OCSP_SINGLERESP_num(br->tbsResponseData->responses); i++) {
		int cert_status, crl_reason;
		OCSP_SINGLERESP *single = NULL;

		ASN1_GENERALIZEDTIME rev, thisupd, *nextupd;

		if(!sk_OCSP_SINGLERESP_value(br->tbsResponseData->responses, i))
		continue;

		single = sk_OCSP_SINGLERESP_value(br->tbsResponseData->responses, i);

		cert_status = OCSP_single_get0_status(single, &crl_reason, &rev,
		&thisupd, &nextupd);

		if(!OCSP_check_validity(thisupd, nextupd, 300L, -1L)) {
		failf(data, "OCSP response has expired");
		result = CURLE_SSL_INVALIDCERTSTATUS;
		goto end;
		}

		infof(data, "SSL certificate status: %s (%d)\n",
		OCSP_cert_status_str(cert_status), cert_status);

		switch(cert_status) {
		case V_OCSP_CERTSTATUS_GOOD:
		break;

		case V_OCSP_CERTSTATUS_REVOKED:
		result = CURLE_SSL_INVALIDCERTSTATUS;

		failf(data, "SSL certificate revocation reason: %s (%d)",
		OCSP_crl_reason_str(crl_reason), crl_reason);
		goto end;

		case V_OCSP_CERTSTATUS_UNKNOWN:
		result = CURLE_SSL_INVALIDCERTSTATUS;
		goto end;
		}
		}

		end:
		if(br) OCSP_BASICRESP_free(br);
		OCSP_RESPONSE_free(rsp);

		return result;
		}

		#endif /* USE_SSLEAY */

		/* The SSL_CTRL_SET_MSG_CALLBACK doesn't exist in ancient OpenSSL versions
		@@ -1930,6 +2055,10 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
		failf(data, "SSL: couldn't create a context (handle)!");
		return CURLE_OUT_OF_MEMORY;
		}

		if(data->set.ssl.verifystatus)
		SSL_set_tlsext_status_type(connssl->handle, TLSEXT_STATUSTYPE_ocsp);

		SSL_set_connect_state(connssl->handle);

		connssl->server_cert = 0x0;
		@@ -2613,6 +2742,15 @@ static CURLcode servercert(struct connectdata *conn,
		infof(data, "\t SSL certificate verify ok.\n");
		}

		if(data->set.ssl.verifystatus) {
		result = verifystatus(conn, connssl);
		if(result) {
		X509_free(connssl->server_cert);
		connssl->server_cert = NULL;
		return result;
		}
		}

		if(!strict)
		/* when not strict, we don't bother about the verify cert problems */
		result = CURLE_OK;
		@@ -3053,4 +3191,9 @@ void Curl_ossl_md5sum(unsigned char tmp, / input */
		MD5_Update(&MD5pw, tmp, tmplen);
		MD5_Final(md5sum, &MD5pw);
		}

		bool Curl_ossl_cert_status_request(void)
		{
		return TRUE;
		}
		#endif /* USE_SSLEAY */

lib/vtls/openssl.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -73,6 +73,8 @@ void Curl_ossl_md5sum(unsigned char tmp, / input */
		unsigned char md5sum / output */,
		size_t unused);

		bool Curl_ossl_cert_status_request(void);

		/* Set the API backend definition to OpenSSL */
		#define CURL_SSL_BACKEND CURLSSLBACKEND_OPENSSL

		@@ -102,6 +104,7 @@ void Curl_ossl_md5sum(unsigned char tmp, / input */
		#define curlssl_data_pending(x,y) Curl_ossl_data_pending(x,y)
		#define curlssl_random(x,y,z) Curl_ossl_random(x,y,z)
		#define curlssl_md5sum(a,b,c,d) Curl_ossl_md5sum(a,b,c,d)
		#define curlssl_cert_status_request() Curl_ossl_cert_status_request()

		#define DEFAULT_CIPHER_SELECTION "ALL!EXPORT!EXPORT40!EXPORT56!aNULL!LOW!RC4"

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