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136504195a
curl/lib/vtls/bearssl.c
Max Faxälv 0a5ea09a91
spnego_gssapi: implement TLS channel bindings for openssl 
Channel Bindings are used to tie the session context to a specific TLS
channel. This is to provide additional proof of valid identity,
mitigating authentication relay attacks.

Major web servers have the ability to require (None/Accept/Require)
GSSAPI channel binding, rendering Curl unable to connect to such
websites unless support for channel bindings is implemented.

IIS calls this feature Extended Protection (EPA), which is used in
Enterprise environments using Kerberos for authentication.

This change require krb5 >= 1.19, otherwise channel bindings won't be
forwarded through SPNEGO.

Co-Authored-By: Steffen Kieß <947515+steffen-kiess@users.noreply.github.com>
Closes #13098
2024-08-12 19:16:54 +02:00

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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) Michael Forney, <mforney@mforney.org>
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
#include "curl_setup.h"
#ifdef USE_BEARSSL
#include <bearssl.h>
#include "bearssl.h"
#include "cipher_suite.h"
#include "urldata.h"
#include "sendf.h"
#include "inet_pton.h"
#include "vtls.h"
#include "vtls_int.h"
#include "connect.h"
#include "select.h"
#include "multiif.h"
#include "curl_printf.h"
/* The last #include files should be: */
#include "curl_memory.h"
#include "memdebug.h"
struct x509_context {
const br_x509_class *vtable;
br_x509_minimal_context minimal;
br_x509_decoder_context decoder;
bool verifyhost;
bool verifypeer;
int cert_num;
};
struct bearssl_ssl_backend_data {
br_ssl_client_context ctx;
struct x509_context x509;
unsigned char buf[BR_SSL_BUFSIZE_BIDI];
br_x509_trust_anchor *anchors;
size_t anchors_len;
const char *protocols[ALPN_ENTRIES_MAX];
/* SSL client context is active */
bool active;
/* size of pending write, yet to be flushed */
size_t pending_write;
BIT(sent_shutdown);
};
struct cafile_parser {
CURLcode err;
bool in_cert;
br_x509_decoder_context xc;
/* array of trust anchors loaded from CAfile */
br_x509_trust_anchor *anchors;
size_t anchors_len;
/* buffer for DN data */
unsigned char dn[1024];
size_t dn_len;
};
#define CAFILE_SOURCE_PATH 1
#define CAFILE_SOURCE_BLOB 2
struct cafile_source {
int type;
const char *data;
size_t len;
};
static void append_dn(void *ctx, const void *buf, size_t len)
{
struct cafile_parser *ca = ctx;
if(ca->err != CURLE_OK || !ca->in_cert)
return;
if(sizeof(ca->dn) - ca->dn_len < len) {
ca->err = CURLE_FAILED_INIT;
return;
}
memcpy(ca->dn + ca->dn_len, buf, len);
ca->dn_len += len;
}
static void x509_push(void *ctx, const void *buf, size_t len)
{
struct cafile_parser *ca = ctx;
if(ca->in_cert)
br_x509_decoder_push(&ca->xc, buf, len);
}
static CURLcode load_cafile(struct cafile_source *source,
br_x509_trust_anchor **anchors,
size_t *anchors_len)
{
struct cafile_parser ca;
br_pem_decoder_context pc;
br_x509_trust_anchor *ta;
size_t ta_size;
br_x509_trust_anchor *new_anchors;
size_t new_anchors_len;
br_x509_pkey *pkey;
FILE *fp = 0;
unsigned char buf[BUFSIZ];
const unsigned char *p = NULL;
const char *name;
size_t n = 0, i, pushed;
DEBUGASSERT(source->type == CAFILE_SOURCE_PATH
|| source->type == CAFILE_SOURCE_BLOB);
if(source->type == CAFILE_SOURCE_PATH) {
fp = fopen(source->data, "rb");
if(!fp)
return CURLE_SSL_CACERT_BADFILE;
}
if(source->type == CAFILE_SOURCE_BLOB && source->len > (size_t)INT_MAX)
return CURLE_SSL_CACERT_BADFILE;
ca.err = CURLE_OK;
ca.in_cert = FALSE;
ca.anchors = NULL;
ca.anchors_len = 0;
br_pem_decoder_init(&pc);
br_pem_decoder_setdest(&pc, x509_push, &ca);
do {
if(source->type == CAFILE_SOURCE_PATH) {
n = fread(buf, 1, sizeof(buf), fp);
if(n == 0)
break;
p = buf;
}
else if(source->type == CAFILE_SOURCE_BLOB) {
n = source->len;
p = (unsigned char *) source->data;
}
while(n) {
pushed = br_pem_decoder_push(&pc, p, n);
if(ca.err)
goto fail;
p += pushed;
n -= pushed;
switch(br_pem_decoder_event(&pc)) {
case 0:
break;
case BR_PEM_BEGIN_OBJ:
name = br_pem_decoder_name(&pc);
if(strcmp(name, "CERTIFICATE") && strcmp(name, "X509 CERTIFICATE"))
break;
br_x509_decoder_init(&ca.xc, append_dn, &ca);
ca.in_cert = TRUE;
ca.dn_len = 0;
break;
case BR_PEM_END_OBJ:
if(!ca.in_cert)
break;
ca.in_cert = FALSE;
if(br_x509_decoder_last_error(&ca.xc)) {
ca.err = CURLE_SSL_CACERT_BADFILE;
goto fail;
}
/* add trust anchor */
if(ca.anchors_len == SIZE_MAX / sizeof(ca.anchors[0])) {
ca.err = CURLE_OUT_OF_MEMORY;
goto fail;
}
new_anchors_len = ca.anchors_len + 1;
new_anchors = realloc(ca.anchors,
new_anchors_len * sizeof(ca.anchors[0]));
if(!new_anchors) {
ca.err = CURLE_OUT_OF_MEMORY;
goto fail;
}
ca.anchors = new_anchors;
ca.anchors_len = new_anchors_len;
ta = &ca.anchors[ca.anchors_len - 1];
ta->dn.data = NULL;
ta->flags = 0;
if(br_x509_decoder_isCA(&ca.xc))
ta->flags |= BR_X509_TA_CA;
pkey = br_x509_decoder_get_pkey(&ca.xc);
if(!pkey) {
ca.err = CURLE_SSL_CACERT_BADFILE;
goto fail;
}
ta->pkey = *pkey;
/* calculate space needed for trust anchor data */
ta_size = ca.dn_len;
switch(pkey->key_type) {
case BR_KEYTYPE_RSA:
ta_size += pkey->key.rsa.nlen + pkey->key.rsa.elen;
break;
case BR_KEYTYPE_EC:
ta_size += pkey->key.ec.qlen;
break;
default:
ca.err = CURLE_FAILED_INIT;
goto fail;
}
/* fill in trust anchor DN and public key data */
ta->dn.data = malloc(ta_size);
if(!ta->dn.data) {
ca.err = CURLE_OUT_OF_MEMORY;
goto fail;
}
memcpy(ta->dn.data, ca.dn, ca.dn_len);
ta->dn.len = ca.dn_len;
switch(pkey->key_type) {
case BR_KEYTYPE_RSA:
ta->pkey.key.rsa.n = ta->dn.data + ta->dn.len;
memcpy(ta->pkey.key.rsa.n, pkey->key.rsa.n, pkey->key.rsa.nlen);
ta->pkey.key.rsa.e = ta->pkey.key.rsa.n + ta->pkey.key.rsa.nlen;
memcpy(ta->pkey.key.rsa.e, pkey->key.rsa.e, pkey->key.rsa.elen);
break;
case BR_KEYTYPE_EC:
ta->pkey.key.ec.q = ta->dn.data + ta->dn.len;
memcpy(ta->pkey.key.ec.q, pkey->key.ec.q, pkey->key.ec.qlen);
break;
}
break;
default:
ca.err = CURLE_SSL_CACERT_BADFILE;
goto fail;
}
}
} while(source->type != CAFILE_SOURCE_BLOB);
if(fp && ferror(fp))
ca.err = CURLE_READ_ERROR;
else if(ca.in_cert)
ca.err = CURLE_SSL_CACERT_BADFILE;
fail:
if(fp)
fclose(fp);
if(ca.err == CURLE_OK) {
*anchors = ca.anchors;
*anchors_len = ca.anchors_len;
}
else {
for(i = 0; i < ca.anchors_len; ++i)
free(ca.anchors[i].dn.data);
free(ca.anchors);
}
return ca.err;
}
static void x509_start_chain(const br_x509_class **ctx,
const char *server_name)
{
struct x509_context *x509 = (struct x509_context *)ctx;
if(!x509->verifypeer) {
x509->cert_num = 0;
return;
}
if(!x509->verifyhost)
server_name = NULL;
x509->minimal.vtable->start_chain(&x509->minimal.vtable, server_name);
}
static void x509_start_cert(const br_x509_class **ctx, uint32_t length)
{
struct x509_context *x509 = (struct x509_context *)ctx;
if(!x509->verifypeer) {
/* Only decode the first cert in the chain to obtain the public key */
if(x509->cert_num == 0)
br_x509_decoder_init(&x509->decoder, NULL, NULL);
return;
}
x509->minimal.vtable->start_cert(&x509->minimal.vtable, length);
}
static void x509_append(const br_x509_class **ctx, const unsigned char *buf,
size_t len)
{
struct x509_context *x509 = (struct x509_context *)ctx;
if(!x509->verifypeer) {
if(x509->cert_num == 0)
br_x509_decoder_push(&x509->decoder, buf, len);
return;
}
x509->minimal.vtable->append(&x509->minimal.vtable, buf, len);
}
static void x509_end_cert(const br_x509_class **ctx)
{
struct x509_context *x509 = (struct x509_context *)ctx;
if(!x509->verifypeer) {
x509->cert_num++;
return;
}
x509->minimal.vtable->end_cert(&x509->minimal.vtable);
}
static unsigned x509_end_chain(const br_x509_class **ctx)
{
struct x509_context *x509 = (struct x509_context *)ctx;
if(!x509->verifypeer) {
return (unsigned)br_x509_decoder_last_error(&x509->decoder);
}
return x509->minimal.vtable->end_chain(&x509->minimal.vtable);
}
static const br_x509_pkey *x509_get_pkey(const br_x509_class *const *ctx,
unsigned *usages)
{
struct x509_context *x509 = (struct x509_context *)ctx;
if(!x509->verifypeer) {
/* Nothing in the chain is verified, just return the public key of the
first certificate and allow its usage for both TLS_RSA_* and
TLS_ECDHE_* */
if(usages)
*usages = BR_KEYTYPE_KEYX | BR_KEYTYPE_SIGN;
return br_x509_decoder_get_pkey(&x509->decoder);
}
return x509->minimal.vtable->get_pkey(&x509->minimal.vtable, usages);
}
static const br_x509_class x509_vtable = {
sizeof(struct x509_context),
x509_start_chain,
x509_start_cert,
x509_append,
x509_end_cert,
x509_end_chain,
x509_get_pkey
};
static const uint16_t ciphertable[] = {
/* RFC 2246 TLS 1.0 */
BR_TLS_RSA_WITH_3DES_EDE_CBC_SHA, /* 0x000A */
/* RFC 3268 TLS 1.0 AES */
BR_TLS_RSA_WITH_AES_128_CBC_SHA, /* 0x002F */
BR_TLS_RSA_WITH_AES_256_CBC_SHA, /* 0x0035 */
/* RFC 5246 TLS 1.2 */
BR_TLS_RSA_WITH_AES_128_CBC_SHA256, /* 0x003C */
BR_TLS_RSA_WITH_AES_256_CBC_SHA256, /* 0x003D */
/* RFC 5288 TLS 1.2 AES GCM */
BR_TLS_RSA_WITH_AES_128_GCM_SHA256, /* 0x009C */
BR_TLS_RSA_WITH_AES_256_GCM_SHA384, /* 0x009D */
/* RFC 4492 TLS 1.0 ECC */
BR_TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA, /* 0xC003 */
BR_TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA, /* 0xC004 */
BR_TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA, /* 0xC005 */
BR_TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA, /* 0xC008 */
BR_TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, /* 0xC009 */
BR_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, /* 0xC00A */
BR_TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA, /* 0xC00D */
BR_TLS_ECDH_RSA_WITH_AES_128_CBC_SHA, /* 0xC00E */
BR_TLS_ECDH_RSA_WITH_AES_256_CBC_SHA, /* 0xC00F */
BR_TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, /* 0xC012 */
BR_TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, /* 0xC013 */
BR_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, /* 0xC014 */
/* RFC 5289 TLS 1.2 ECC HMAC SHA256/384 */
BR_TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, /* 0xC023 */
BR_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384, /* 0xC024 */
BR_TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256, /* 0xC025 */
BR_TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384, /* 0xC026 */
BR_TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, /* 0xC027 */
BR_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384, /* 0xC028 */
BR_TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256, /* 0xC029 */
BR_TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384, /* 0xC02A */
/* RFC 5289 TLS 1.2 GCM */
BR_TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, /* 0xC02B */
BR_TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, /* 0xC02C */
BR_TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256, /* 0xC02D */
BR_TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384, /* 0xC02E */
BR_TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, /* 0xC02F */
BR_TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, /* 0xC030 */
BR_TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256, /* 0xC031 */
BR_TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384, /* 0xC032 */
#ifdef BR_TLS_RSA_WITH_AES_128_CCM
/* RFC 6655 TLS 1.2 CCM
Supported since BearSSL 0.6 */
BR_TLS_RSA_WITH_AES_128_CCM, /* 0xC09C */
BR_TLS_RSA_WITH_AES_256_CCM, /* 0xC09D */
BR_TLS_RSA_WITH_AES_128_CCM_8, /* 0xC0A0 */
BR_TLS_RSA_WITH_AES_256_CCM_8, /* 0xC0A1 */
/* RFC 7251 TLS 1.2 ECC CCM
Supported since BearSSL 0.6 */
BR_TLS_ECDHE_ECDSA_WITH_AES_128_CCM, /* 0xC0AC */
BR_TLS_ECDHE_ECDSA_WITH_AES_256_CCM, /* 0xC0AD */
BR_TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8, /* 0xC0AE */
BR_TLS_ECDHE_ECDSA_WITH_AES_256_CCM_8, /* 0xC0AF */
#endif
/* RFC 7905 TLS 1.2 ChaCha20-Poly1305
Supported since BearSSL 0.2 */
BR_TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, /* 0xCCA8 */
BR_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, /* 0xCCA9 */
};
#define NUM_OF_CIPHERS (sizeof(ciphertable) / sizeof(ciphertable[0]))
static CURLcode bearssl_set_selected_ciphers(struct Curl_easy *data,
br_ssl_engine_context *ssl_eng,
const char *ciphers)
{
uint16_t selected[NUM_OF_CIPHERS];
size_t count = 0, i;
const char *ptr, *end;
for(ptr = ciphers; ptr[0] != '\0' && count < NUM_OF_CIPHERS; ptr = end) {
uint16_t id = Curl_cipher_suite_walk_str(&ptr, &end);
/* Check if cipher is supported */
if(id) {
for(i = 0; i < NUM_OF_CIPHERS && ciphertable[i] != id; i++);
if(i == NUM_OF_CIPHERS)
id = 0;
}
if(!id) {
if(ptr[0] != '\0')
infof(data, "BearSSL: unknown cipher in list: \"%.*s\"",
(int) (end - ptr), ptr);
continue;
}
/* No duplicates allowed */
for(i = 0; i < count && selected[i] != id; i++);
if(i < count) {
infof(data, "BearSSL: duplicate cipher in list: \"%.*s\"",
(int) (end - ptr), ptr);
continue;
}
selected[count++] = id;
}
if(count == 0) {
failf(data, "BearSSL: no supported cipher in list");
return CURLE_SSL_CIPHER;
}
br_ssl_engine_set_suites(ssl_eng, selected, count);
return CURLE_OK;
}
static CURLcode bearssl_connect_step1(struct Curl_cfilter *cf,
struct Curl_easy *data)
{
struct ssl_connect_data *connssl = cf->ctx;
struct bearssl_ssl_backend_data *backend =
(struct bearssl_ssl_backend_data *)connssl->backend;
struct ssl_primary_config *conn_config = Curl_ssl_cf_get_primary_config(cf);
struct ssl_config_data *ssl_config = Curl_ssl_cf_get_config(cf, data);
const struct curl_blob *ca_info_blob = conn_config->ca_info_blob;
const char * const ssl_cafile =
/* CURLOPT_CAINFO_BLOB overrides CURLOPT_CAINFO */
(ca_info_blob ? NULL : conn_config->CAfile);
const char *hostname = connssl->peer.hostname;
const bool verifypeer = conn_config->verifypeer;
const bool verifyhost = conn_config->verifyhost;
CURLcode ret;
unsigned version_min, version_max;
int session_set = 0;
DEBUGASSERT(backend);
CURL_TRC_CF(data, cf, "connect_step1");
switch(conn_config->version) {
case CURL_SSLVERSION_SSLv2:
failf(data, "BearSSL does not support SSLv2");
return CURLE_SSL_CONNECT_ERROR;
case CURL_SSLVERSION_SSLv3:
failf(data, "BearSSL does not support SSLv3");
return CURLE_SSL_CONNECT_ERROR;
case CURL_SSLVERSION_TLSv1_0:
version_min = BR_TLS10;
version_max = BR_TLS10;
break;
case CURL_SSLVERSION_TLSv1_1:
version_min = BR_TLS11;
version_max = BR_TLS11;
break;
case CURL_SSLVERSION_TLSv1_2:
version_min = BR_TLS12;
version_max = BR_TLS12;
break;
case CURL_SSLVERSION_DEFAULT:
case CURL_SSLVERSION_TLSv1:
version_min = BR_TLS10;
version_max = BR_TLS12;
break;
default:
failf(data, "BearSSL: unknown CURLOPT_SSLVERSION");
return CURLE_SSL_CONNECT_ERROR;
}
if(verifypeer) {
if(ca_info_blob) {
struct cafile_source source;
source.type = CAFILE_SOURCE_BLOB;
source.data = ca_info_blob->data;
source.len = ca_info_blob->len;
CURL_TRC_CF(data, cf, "connect_step1, load ca_info_blob");
ret = load_cafile(&source, &backend->anchors, &backend->anchors_len);
if(ret != CURLE_OK) {
failf(data, "error importing CA certificate blob");
return ret;
}
}
if(ssl_cafile) {
struct cafile_source source;
source.type = CAFILE_SOURCE_PATH;
source.data = ssl_cafile;
source.len = 0;
CURL_TRC_CF(data, cf, "connect_step1, load cafile");
ret = load_cafile(&source, &backend->anchors, &backend->anchors_len);
if(ret != CURLE_OK) {
failf(data, "error setting certificate verify locations."
" CAfile: %s", ssl_cafile);
return ret;
}
}
}
/* initialize SSL context */
br_ssl_client_init_full(&backend->ctx, &backend->x509.minimal,
backend->anchors, backend->anchors_len);
br_ssl_engine_set_versions(&backend->ctx.eng, version_min, version_max);
br_ssl_engine_set_buffer(&backend->ctx.eng, backend->buf,
sizeof(backend->buf), 1);
if(conn_config->cipher_list) {
/* Override the ciphers as specified. For the default cipher list see the
BearSSL source code of br_ssl_client_init_full() */
CURL_TRC_CF(data, cf, "connect_step1, set ciphers");
ret = bearssl_set_selected_ciphers(data, &backend->ctx.eng,
conn_config->cipher_list);
if(ret)
return ret;
}
/* initialize X.509 context */
backend->x509.vtable = &x509_vtable;
backend->x509.verifypeer = verifypeer;
backend->x509.verifyhost = verifyhost;
br_ssl_engine_set_x509(&backend->ctx.eng, &backend->x509.vtable);
if(ssl_config->primary.cache_session) {
void *session;
CURL_TRC_CF(data, cf, "connect_step1, check session cache");
Curl_ssl_sessionid_lock(data);
if(!Curl_ssl_getsessionid(cf, data, &connssl->peer, &session, NULL)) {
br_ssl_engine_set_session_parameters(&backend->ctx.eng, session);
session_set = 1;
infof(data, "BearSSL: reusing session ID");
}
Curl_ssl_sessionid_unlock(data);
}
if(connssl->alpn) {
struct alpn_proto_buf proto;
size_t i;
for(i = 0; i < connssl->alpn->count; ++i) {
backend->protocols[i] = connssl->alpn->entries[i];
}
br_ssl_engine_set_protocol_names(&backend->ctx.eng, backend->protocols,
connssl->alpn->count);
Curl_alpn_to_proto_str(&proto, connssl->alpn);
infof(data, VTLS_INFOF_ALPN_OFFER_1STR, proto.data);
}
if(connssl->peer.type != CURL_SSL_PEER_DNS) {
if(verifyhost) {
failf(data, "BearSSL: "
"host verification of IP address is not supported");
return CURLE_PEER_FAILED_VERIFICATION;
}
hostname = NULL;
}
else {
if(!connssl->peer.sni) {
failf(data, "Failed to set SNI");
return CURLE_SSL_CONNECT_ERROR;
}
hostname = connssl->peer.sni;
CURL_TRC_CF(data, cf, "connect_step1, SNI set");
}
/* give application a chance to interfere with SSL set up. */
if(data->set.ssl.fsslctx) {
Curl_set_in_callback(data, true);
ret = (*data->set.ssl.fsslctx)(data, &backend->ctx,
data->set.ssl.fsslctxp);
Curl_set_in_callback(data, false);
if(ret) {
failf(data, "BearSSL: error signaled by ssl ctx callback");
return ret;
}
}
if(!br_ssl_client_reset(&backend->ctx, hostname, session_set))
return CURLE_FAILED_INIT;
backend->active = TRUE;
connssl->connecting_state = ssl_connect_2;
return CURLE_OK;
}
static CURLcode bearssl_run_until(struct Curl_cfilter *cf,
struct Curl_easy *data,
unsigned target)
{
struct ssl_connect_data *connssl = cf->ctx;
struct bearssl_ssl_backend_data *backend =
(struct bearssl_ssl_backend_data *)connssl->backend;
unsigned state;
unsigned char *buf;
size_t len;
ssize_t ret;
CURLcode result;
int err;
DEBUGASSERT(backend);
connssl->io_need = CURL_SSL_IO_NEED_NONE;
for(;;) {
state = br_ssl_engine_current_state(&backend->ctx.eng);
if(state & BR_SSL_CLOSED) {
err = br_ssl_engine_last_error(&backend->ctx.eng);
switch(err) {
case BR_ERR_OK:
/* TLS close notify */
if(connssl->state != ssl_connection_complete) {
failf(data, "SSL: connection closed during handshake");
return CURLE_SSL_CONNECT_ERROR;
}
return CURLE_OK;
case BR_ERR_X509_EXPIRED:
failf(data, "SSL: X.509 verification: "
"certificate is expired or not yet valid");
return CURLE_PEER_FAILED_VERIFICATION;
case BR_ERR_X509_BAD_SERVER_NAME:
failf(data, "SSL: X.509 verification: "
"expected server name was not found in the chain");
return CURLE_PEER_FAILED_VERIFICATION;
case BR_ERR_X509_NOT_TRUSTED:
failf(data, "SSL: X.509 verification: "
"chain could not be linked to a trust anchor");
return CURLE_PEER_FAILED_VERIFICATION;
}
/* X.509 errors are documented to have the range 32..63 */
if(err >= 32 && err < 64)
return CURLE_PEER_FAILED_VERIFICATION;
return CURLE_SSL_CONNECT_ERROR;
}
if(state & target)
return CURLE_OK;
if(state & BR_SSL_SENDREC) {
buf = br_ssl_engine_sendrec_buf(&backend->ctx.eng, &len);
ret = Curl_conn_cf_send(cf->next, data, (char *)buf, len, FALSE,
&result);
CURL_TRC_CF(data, cf, "ssl_send(len=%zu) -> %zd, %d", len, ret, result);
if(ret <= 0) {
if(result == CURLE_AGAIN)
connssl->io_need |= CURL_SSL_IO_NEED_SEND;
return result;
}
br_ssl_engine_sendrec_ack(&backend->ctx.eng, ret);
}
else if(state & BR_SSL_RECVREC) {
buf = br_ssl_engine_recvrec_buf(&backend->ctx.eng, &len);
ret = Curl_conn_cf_recv(cf->next, data, (char *)buf, len, &result);
CURL_TRC_CF(data, cf, "ssl_recv(len=%zu) -> %zd, %d", len, ret, result);
if(ret == 0) {
failf(data, "SSL: EOF without close notify");
return CURLE_RECV_ERROR;
}
if(ret <= 0) {
if(result == CURLE_AGAIN)
connssl->io_need |= CURL_SSL_IO_NEED_RECV;
return result;
}
br_ssl_engine_recvrec_ack(&backend->ctx.eng, ret);
}
}
}
static CURLcode bearssl_connect_step2(struct Curl_cfilter *cf,
struct Curl_easy *data)
{
struct ssl_connect_data *connssl = cf->ctx;
struct bearssl_ssl_backend_data *backend =
(struct bearssl_ssl_backend_data *)connssl->backend;
br_ssl_session_parameters session;
char cipher_str[64];
char ver_str[16];
CURLcode ret;
DEBUGASSERT(backend);
CURL_TRC_CF(data, cf, "connect_step2");
ret = bearssl_run_until(cf, data, BR_SSL_SENDAPP | BR_SSL_RECVAPP);
if(ret == CURLE_AGAIN)
return CURLE_OK;
if(ret == CURLE_OK) {
unsigned int tver;
if(br_ssl_engine_current_state(&backend->ctx.eng) == BR_SSL_CLOSED) {
failf(data, "SSL: connection closed during handshake");
return CURLE_SSL_CONNECT_ERROR;
}
connssl->connecting_state = ssl_connect_3;
/* Informational message */
tver = br_ssl_engine_get_version(&backend->ctx.eng);
if(tver == BR_TLS12)
strcpy(ver_str, "TLSv1.2");
else if(tver == BR_TLS11)
strcpy(ver_str, "TLSv1.1");
else if(tver == BR_TLS10)
strcpy(ver_str, "TLSv1.0");
else {
msnprintf(ver_str, sizeof(ver_str), "TLS 0x%04x", tver);
}
br_ssl_engine_get_session_parameters(&backend->ctx.eng, &session);
Curl_cipher_suite_get_str(session.cipher_suite, cipher_str,
sizeof(cipher_str), true);
infof(data, "BearSSL: %s connection using %s", ver_str, cipher_str);
}
return ret;
}
static void bearssl_session_free(void *sessionid, size_t idsize)
{
(void)idsize;
free(sessionid);
}
static CURLcode bearssl_connect_step3(struct Curl_cfilter *cf,
struct Curl_easy *data)
{
struct ssl_connect_data *connssl = cf->ctx;
struct bearssl_ssl_backend_data *backend =
(struct bearssl_ssl_backend_data *)connssl->backend;
struct ssl_config_data *ssl_config = Curl_ssl_cf_get_config(cf, data);
CURLcode ret;
DEBUGASSERT(ssl_connect_3 == connssl->connecting_state);
DEBUGASSERT(backend);
CURL_TRC_CF(data, cf, "connect_step3");
if(connssl->alpn) {
const char *proto;
proto = br_ssl_engine_get_selected_protocol(&backend->ctx.eng);
Curl_alpn_set_negotiated(cf, data, (const unsigned char *)proto,
proto? strlen(proto) : 0);
}
if(ssl_config->primary.cache_session) {
br_ssl_session_parameters *session;
session = malloc(sizeof(*session));
if(!session)
return CURLE_OUT_OF_MEMORY;
br_ssl_engine_get_session_parameters(&backend->ctx.eng, session);
Curl_ssl_sessionid_lock(data);
ret = Curl_ssl_set_sessionid(cf, data, &connssl->peer, session, 0,
bearssl_session_free);
Curl_ssl_sessionid_unlock(data);
if(ret)
return ret;
}
connssl->connecting_state = ssl_connect_done;
return CURLE_OK;
}
static ssize_t bearssl_send(struct Curl_cfilter *cf, struct Curl_easy *data,
const void *buf, size_t len, CURLcode *err)
{
struct ssl_connect_data *connssl = cf->ctx;
struct bearssl_ssl_backend_data *backend =
(struct bearssl_ssl_backend_data *)connssl->backend;
unsigned char *app;
size_t applen;
DEBUGASSERT(backend);
for(;;) {
*err = bearssl_run_until(cf, data, BR_SSL_SENDAPP);
if(*err)
return -1;
app = br_ssl_engine_sendapp_buf(&backend->ctx.eng, &applen);
if(!app) {
failf(data, "SSL: connection closed during write");
*err = CURLE_SEND_ERROR;
return -1;
}
if(backend->pending_write) {
applen = backend->pending_write;
backend->pending_write = 0;
return applen;
}
if(applen > len)
applen = len;
memcpy(app, buf, applen);
br_ssl_engine_sendapp_ack(&backend->ctx.eng, applen);
br_ssl_engine_flush(&backend->ctx.eng, 0);
backend->pending_write = applen;
}
}
static ssize_t bearssl_recv(struct Curl_cfilter *cf, struct Curl_easy *data,
char *buf, size_t len, CURLcode *err)
{
struct ssl_connect_data *connssl = cf->ctx;
struct bearssl_ssl_backend_data *backend =
(struct bearssl_ssl_backend_data *)connssl->backend;
unsigned char *app;
size_t applen;
DEBUGASSERT(backend);
*err = bearssl_run_until(cf, data, BR_SSL_RECVAPP);
if(*err != CURLE_OK)
return -1;
app = br_ssl_engine_recvapp_buf(&backend->ctx.eng, &applen);
if(!app)
return 0;
if(applen > len)
applen = len;
memcpy(buf, app, applen);
br_ssl_engine_recvapp_ack(&backend->ctx.eng, applen);
return applen;
}
static CURLcode bearssl_connect_common(struct Curl_cfilter *cf,
struct Curl_easy *data,
bool nonblocking,
bool *done)
{
CURLcode ret;
struct ssl_connect_data *connssl = cf->ctx;
curl_socket_t sockfd = Curl_conn_cf_get_socket(cf, data);
timediff_t timeout_ms;
int what;
CURL_TRC_CF(data, cf, "connect_common(blocking=%d)", !nonblocking);
/* check if the connection has already been established */
if(ssl_connection_complete == connssl->state) {
CURL_TRC_CF(data, cf, "connect_common, connected");
*done = TRUE;
return CURLE_OK;
}
if(ssl_connect_1 == connssl->connecting_state) {
ret = bearssl_connect_step1(cf, data);
if(ret)
return ret;
}
while(ssl_connect_2 == connssl->connecting_state) {
/* check allowed time left */
timeout_ms = Curl_timeleft(data, NULL, TRUE);
if(timeout_ms < 0) {
/* no need to continue if time already is up */
failf(data, "SSL connection timeout");
return CURLE_OPERATION_TIMEDOUT;
}
/* if ssl is expecting something, check if it is available. */
if(connssl->io_need) {
curl_socket_t writefd = (connssl->io_need & CURL_SSL_IO_NEED_SEND)?
sockfd:CURL_SOCKET_BAD;
curl_socket_t readfd = (connssl->io_need & CURL_SSL_IO_NEED_RECV)?
sockfd:CURL_SOCKET_BAD;
CURL_TRC_CF(data, cf, "connect_common, check socket");
what = Curl_socket_check(readfd, CURL_SOCKET_BAD, writefd,
nonblocking?0:timeout_ms);
CURL_TRC_CF(data, cf, "connect_common, check socket -> %d", what);
if(what < 0) {
/* fatal error */
failf(data, "select/poll on SSL socket, errno: %d", SOCKERRNO);
return CURLE_SSL_CONNECT_ERROR;
}
else if(0 == what) {
if(nonblocking) {
*done = FALSE;
return CURLE_OK;
}
else {
/* timeout */
failf(data, "SSL connection timeout");
return CURLE_OPERATION_TIMEDOUT;
}
}
/* socket is readable or writable */
}
/* Run transaction, and return to the caller if it failed or if this
* connection is done nonblocking and this loop would execute again. This
* permits the owner of a multi handle to abort a connection attempt
* before step2 has completed while ensuring that a client using select()
* or epoll() will always have a valid fdset to wait on.
*/
connssl->io_need = CURL_SSL_IO_NEED_NONE;
ret = bearssl_connect_step2(cf, data);
if(ret || (nonblocking && (ssl_connect_2 == connssl->connecting_state)))
return ret;
}
if(ssl_connect_3 == connssl->connecting_state) {
ret = bearssl_connect_step3(cf, data);
if(ret)
return ret;
}
if(ssl_connect_done == connssl->connecting_state) {
connssl->state = ssl_connection_complete;
*done = TRUE;
}
else
*done = FALSE;
/* Reset our connect state machine */
connssl->connecting_state = ssl_connect_1;
return CURLE_OK;
}
static size_t bearssl_version(char *buffer, size_t size)
{
return msnprintf(buffer, size, "BearSSL");
}
static bool bearssl_data_pending(struct Curl_cfilter *cf,
const struct Curl_easy *data)
{
struct ssl_connect_data *ctx = cf->ctx;
struct bearssl_ssl_backend_data *backend;
(void)data;
DEBUGASSERT(ctx && ctx->backend);
backend = (struct bearssl_ssl_backend_data *)ctx->backend;
return br_ssl_engine_current_state(&backend->ctx.eng) & BR_SSL_RECVAPP;
}
static CURLcode bearssl_random(struct Curl_easy *data UNUSED_PARAM,
unsigned char *entropy, size_t length)
{
static br_hmac_drbg_context ctx;
static bool seeded = FALSE;
if(!seeded) {
br_prng_seeder seeder;
br_hmac_drbg_init(&ctx, &br_sha256_vtable, NULL, 0);
seeder = br_prng_seeder_system(NULL);
if(!seeder || !seeder(&ctx.vtable))
return CURLE_FAILED_INIT;
seeded = TRUE;
}
br_hmac_drbg_generate(&ctx, entropy, length);
return CURLE_OK;
}
static CURLcode bearssl_connect(struct Curl_cfilter *cf,
struct Curl_easy *data)
{
CURLcode ret;
bool done = FALSE;
ret = bearssl_connect_common(cf, data, FALSE, &done);
if(ret)
return ret;
DEBUGASSERT(done);
return CURLE_OK;
}
static CURLcode bearssl_connect_nonblocking(struct Curl_cfilter *cf,
struct Curl_easy *data,
bool *done)
{
return bearssl_connect_common(cf, data, TRUE, done);
}
static void *bearssl_get_internals(struct ssl_connect_data *connssl,
CURLINFO info UNUSED_PARAM)
{
struct bearssl_ssl_backend_data *backend =
(struct bearssl_ssl_backend_data *)connssl->backend;
DEBUGASSERT(backend);
return &backend->ctx;
}
static CURLcode bearssl_shutdown(struct Curl_cfilter *cf,
struct Curl_easy *data,
bool send_shutdown, bool *done)
{
struct ssl_connect_data *connssl = cf->ctx;
struct bearssl_ssl_backend_data *backend =
(struct bearssl_ssl_backend_data *)connssl->backend;
CURLcode result;
DEBUGASSERT(backend);
if(!backend->active || cf->shutdown) {
*done = TRUE;
return CURLE_OK;
}
*done = FALSE;
if(!backend->sent_shutdown) {
(void)send_shutdown; /* unknown how to suppress our close notify */
br_ssl_engine_close(&backend->ctx.eng);
backend->sent_shutdown = TRUE;
}
result = bearssl_run_until(cf, data, BR_SSL_CLOSED);
if(result == CURLE_OK) {
*done = TRUE;
}
else if(result == CURLE_AGAIN) {
CURL_TRC_CF(data, cf, "shutdown EAGAIN, io_need=%x", connssl->io_need);
result = CURLE_OK;
}
else
CURL_TRC_CF(data, cf, "shutdown error: %d", result);
cf->shutdown = (result || *done);
return result;
}
static void bearssl_close(struct Curl_cfilter *cf, struct Curl_easy *data)
{
struct ssl_connect_data *connssl = cf->ctx;
struct bearssl_ssl_backend_data *backend =
(struct bearssl_ssl_backend_data *)connssl->backend;
size_t i;
(void)data;
DEBUGASSERT(backend);
backend->active = FALSE;
if(backend->anchors) {
for(i = 0; i < backend->anchors_len; ++i)
free(backend->anchors[i].dn.data);
Curl_safefree(backend->anchors);
}
}
static CURLcode bearssl_sha256sum(const unsigned char *input,
size_t inputlen,
unsigned char *sha256sum,
size_t sha256len UNUSED_PARAM)
{
br_sha256_context ctx;
br_sha256_init(&ctx);
br_sha256_update(&ctx, input, inputlen);
br_sha256_out(&ctx, sha256sum);
return CURLE_OK;
}
const struct Curl_ssl Curl_ssl_bearssl = {
{ CURLSSLBACKEND_BEARSSL, "bearssl" }, /* info */
SSLSUPP_CAINFO_BLOB |
SSLSUPP_SSL_CTX |
SSLSUPP_HTTPS_PROXY |
SSLSUPP_CIPHER_LIST,
sizeof(struct bearssl_ssl_backend_data),
Curl_none_init, /* init */
Curl_none_cleanup, /* cleanup */
bearssl_version, /* version */
Curl_none_check_cxn, /* check_cxn */
bearssl_shutdown, /* shutdown */
bearssl_data_pending, /* data_pending */
bearssl_random, /* random */
Curl_none_cert_status_request, /* cert_status_request */
bearssl_connect, /* connect */
bearssl_connect_nonblocking, /* connect_nonblocking */
Curl_ssl_adjust_pollset, /* adjust_pollset */
bearssl_get_internals, /* get_internals */
bearssl_close, /* close_one */
Curl_none_close_all, /* close_all */
Curl_none_set_engine, /* set_engine */
Curl_none_set_engine_default, /* set_engine_default */
Curl_none_engines_list, /* engines_list */
Curl_none_false_start, /* false_start */
bearssl_sha256sum, /* sha256sum */
NULL, /* associate_connection */
NULL, /* disassociate_connection */
bearssl_recv, /* recv decrypted data */
bearssl_send, /* send data to encrypt */
NULL, /* get_channel_binding */
};
#endif /* USE_BEARSSL */
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