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ssl.c
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ssl.c
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/*
* Part of Very Secure FTPd
* Licence: GPL v2. Note that this code interfaces with with the OpenSSL
* libraries, so please read LICENSE where I give explicit permission to link
* against the OpenSSL libraries.
* Author: Chris Evans
* ssl.c
*
* Routines to handle a SSL/TLS-based implementation of RFC 2228, i.e.
* encryption.
*/
#include "ssl.h"
#include "session.h"
#include "ftpcodes.h"
#include "ftpcmdio.h"
#include "defs.h"
#include "str.h"
#include "sysutil.h"
#include "tunables.h"
#include "utility.h"
#include "builddefs.h"
#include "logging.h"
#ifdef VSF_BUILD_SSL
#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/rand.h>
#include <openssl/bio.h>
#include <openssl/dh.h>
#include <openssl/bn.h>
#include <errno.h>
#include <limits.h>
static char* get_ssl_error();
static SSL* get_ssl(struct vsf_session* p_sess, int fd);
static int ssl_session_init(struct vsf_session* p_sess);
static void setup_bio_callbacks();
static long bio_callback(
BIO* p_bio, int oper, const char* p_arg, int argi, long argl, long retval);
static int ssl_verify_callback(int verify_ok, X509_STORE_CTX* p_ctx);
static DH *ssl_tmp_dh_callback(SSL *ssl, int is_export, int keylength);
static int ssl_alpn_callback(SSL* p_ssl,
const unsigned char** p_out,
unsigned char* outlen,
const unsigned char* p_in,
unsigned int inlen,
void* p_arg);
static long ssl_sni_callback(SSL* p_ssl, int* p_al, void* p_arg);
static int ssl_cert_digest(
SSL* p_ssl, struct vsf_session* p_sess, struct mystr* p_str);
static void maybe_log_shutdown_state(struct vsf_session* p_sess);
static void maybe_log_ssl_error_state(struct vsf_session* p_sess, int ret);
static int ssl_read_common(struct vsf_session* p_sess,
SSL* p_ssl,
char* p_buf,
unsigned int len,
int (*p_ssl_func)(SSL*, void*, int));
static int ssl_inited;
static struct mystr debug_str;
// Grab prime number from OpenSSL; <openssl/bn.h>
// (get_rfc*) for all available primes.
// wraps selection of comparable algorithm strength
#if !defined(match_dh_bits)
#define match_dh_bits(keylen) \
keylen >= 8191 ? 8192 : \
keylen >= 6143 ? 6144 : \
keylen >= 4095 ? 4096 : \
keylen >= 3071 ? 3072 : \
keylen >= 2047 ? 2048 : \
keylen >= 1535 ? 1536 : \
keylen >= 1023 ? 1024 : 768
#endif
#if !defined(DH_get_prime)
BIGNUM *
DH_get_prime(int bits)
{
switch (bits) {
case 768: return get_rfc2409_prime_768(NULL);
case 1024: return get_rfc2409_prime_1024(NULL);
case 1536: return get_rfc3526_prime_1536(NULL);
case 2048: return get_rfc3526_prime_2048(NULL);
case 3072: return get_rfc3526_prime_3072(NULL);
case 4096: return get_rfc3526_prime_4096(NULL);
case 6144: return get_rfc3526_prime_6144(NULL);
case 8192: return get_rfc3526_prime_8192(NULL);
// shouldn't happen when used match_dh_bits; strict compiler
default: return NULL;
}
}
#endif
#if OPENSSL_VERSION_NUMBER < 0x10100000L
int DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g)
{
/* If the fields p and g in d are NULL, the corresponding input
* parameters MUST be non-NULL. q may remain NULL.
*/
if ((dh->p == NULL && p == NULL)
|| (dh->g == NULL && g == NULL))
return 0;
if (p != NULL) {
BN_free(dh->p);
dh->p = p;
}
if (q != NULL) {
BN_free(dh->q);
dh->q = q;
}
if (g != NULL) {
BN_free(dh->g);
dh->g = g;
}
if (q != NULL) {
dh->length = BN_num_bits(q);
}
return 1;
}
#endif
#if !defined(DH_get_dh)
// Grab DH parameters
DH *
DH_get_dh(int size)
{
BIGNUM *g = NULL;
BIGNUM *p = NULL;
DH *dh = DH_new();
if (!dh) {
return NULL;
}
p = DH_get_prime(match_dh_bits(size));
BN_dec2bn(&g, "2");
if (!p || !g || !DH_set0_pqg(dh, p, NULL, g))
{
BN_free(g);
BN_free(p);
DH_free(dh);
return NULL;
}
return dh;
}
#endif
void
ssl_init(struct vsf_session* p_sess)
{
if (!ssl_inited)
{
SSL_CTX* p_ctx;
long options;
int verify_option = 0;
SSL_library_init();
p_ctx = SSL_CTX_new(SSLv23_server_method());
if (p_ctx == NULL)
{
die("SSL: could not allocate SSL context");
}
options = SSL_OP_ALL | SSL_OP_SINGLE_DH_USE | SSL_OP_SINGLE_ECDH_USE;
if (!tunable_sslv2)
{
options |= SSL_OP_NO_SSLv2;
}
if (!tunable_sslv3)
{
options |= SSL_OP_NO_SSLv3;
}
if (!tunable_tlsv1)
{
options |= SSL_OP_NO_TLSv1;
}
if (!tunable_tlsv1_1)
{
options |= SSL_OP_NO_TLSv1_1;
}
if (!tunable_tlsv1_2)
{
options |= SSL_OP_NO_TLSv1_2;
}
if (!tunable_tlsv1_3)
{
options |= SSL_OP_NO_TLSv1_3;
}
SSL_CTX_set_options(p_ctx, options);
if (tunable_rsa_cert_file)
{
const char* p_key = tunable_rsa_private_key_file;
if (!p_key)
{
p_key = tunable_rsa_cert_file;
}
if (SSL_CTX_use_certificate_chain_file(p_ctx, tunable_rsa_cert_file) != 1)
{
die("SSL: cannot load RSA certificate");
}
if (SSL_CTX_use_PrivateKey_file(p_ctx, p_key, X509_FILETYPE_PEM) != 1)
{
die("SSL: cannot load RSA private key");
}
}
if (tunable_dsa_cert_file)
{
const char* p_key = tunable_dsa_private_key_file;
if (!p_key)
{
p_key = tunable_dsa_cert_file;
}
if (SSL_CTX_use_certificate_chain_file(p_ctx, tunable_dsa_cert_file) != 1)
{
die("SSL: cannot load DSA certificate");
}
if (SSL_CTX_use_PrivateKey_file(p_ctx, p_key, X509_FILETYPE_PEM) != 1)
{
die("SSL: cannot load DSA private key");
}
}
if (tunable_dh_param_file)
{
BIO *bio;
DH *dhparams = NULL;
if ((bio = BIO_new_file(tunable_dh_param_file, "r")) == NULL)
{
die("SSL: cannot load custom DH params");
}
else
{
dhparams = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
BIO_free(bio);
if (!SSL_CTX_set_tmp_dh(p_ctx, dhparams))
{
die("SSL: setting custom DH params failed");
}
}
}
if (tunable_ssl_ciphers &&
SSL_CTX_set_cipher_list(p_ctx, tunable_ssl_ciphers) != 1)
{
die("SSL: could not set cipher list");
}
if (RAND_status() != 1)
{
die("SSL: RNG is not seeded");
}
{
EC_KEY* key = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
if (key == NULL)
{
die("SSL: failed to get curve p256");
}
SSL_CTX_set_tmp_ecdh(p_ctx, key);
EC_KEY_free(key);
}
if (tunable_ssl_request_cert)
{
verify_option |= SSL_VERIFY_PEER;
}
if (tunable_require_cert)
{
verify_option |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
}
if (verify_option)
{
SSL_CTX_set_verify(p_ctx, verify_option, ssl_verify_callback);
if (tunable_ca_certs_file)
{
STACK_OF(X509_NAME)* p_names;
if (!SSL_CTX_load_verify_locations(p_ctx, tunable_ca_certs_file, NULL))
{
die("SSL: could not load verify file");
}
p_names = SSL_load_client_CA_file(tunable_ca_certs_file);
if (!p_names)
{
die("SSL: could not load client certs file");
}
SSL_CTX_set_client_CA_list(p_ctx, p_names);
}
}
{
static const char* p_ctx_id = "vsftpd";
SSL_CTX_set_session_id_context(p_ctx, (void*) p_ctx_id,
vsf_sysutil_strlen(p_ctx_id));
}
if (tunable_require_ssl_reuse)
{
/* Ensure cached session doesn't expire */
SSL_CTX_set_timeout(p_ctx, INT_MAX);
}
SSL_CTX_set_tmp_dh_callback(p_ctx, ssl_tmp_dh_callback);
/* Set up ALPN to check for FTP protocol intention of client. */
SSL_CTX_set_alpn_select_cb(p_ctx, ssl_alpn_callback, p_sess);
/* Set up SNI callback for an optional hostname check. */
SSL_CTX_set_tlsext_servername_callback(p_ctx, ssl_sni_callback);
SSL_CTX_set_tlsext_servername_arg(p_ctx, p_sess);
if (tunable_ecdh_param_file)
{
BIO *bio;
int nid;
EC_GROUP *ecparams = NULL;
EC_KEY *eckey;
if ((bio = BIO_new_file(tunable_ecdh_param_file, "r")) == NULL)
die("SSL: cannot load custom ec params");
else
{
ecparams = PEM_read_bio_ECPKParameters(bio, NULL, NULL, NULL);
BIO_free(bio);
if (ecparams && (nid = EC_GROUP_get_curve_name(ecparams)) &&
(eckey = EC_KEY_new_by_curve_name(nid)))
{
if (!SSL_CTX_set_tmp_ecdh(p_ctx, eckey))
die("SSL: setting custom EC params failed");
}
else
{
die("SSL: getting ec group or key failed");
}
}
}
else
{
#if defined(SSL_CTX_set_ecdh_auto)
SSL_CTX_set_ecdh_auto(p_ctx, 1);
#else
SSL_CTX_set_tmp_ecdh(p_ctx, EC_KEY_new_by_curve_name(NID_X9_62_prime256v1));
#endif
}
p_sess->p_ssl_ctx = p_ctx;
ssl_inited = 1;
}
}
void
ssl_control_handshake(struct vsf_session* p_sess)
{
if (!ssl_session_init(p_sess))
{
struct mystr err_str = INIT_MYSTR;
str_alloc_text(&err_str, "Negotiation failed: ");
/* Technically, we shouldn't leak such detailed error messages. */
str_append_text(&err_str, get_ssl_error());
vsf_cmdio_write_str(p_sess, FTP_TLS_FAIL, &err_str);
vsf_sysutil_exit(1);
}
p_sess->control_use_ssl = 1;
}
void
handle_auth(struct vsf_session* p_sess)
{
str_upper(&p_sess->ftp_arg_str);
if (str_equal_text(&p_sess->ftp_arg_str, "TLS") ||
str_equal_text(&p_sess->ftp_arg_str, "TLS-C") ||
str_equal_text(&p_sess->ftp_arg_str, "SSL") ||
str_equal_text(&p_sess->ftp_arg_str, "TLS-P"))
{
vsf_cmdio_write(p_sess, FTP_AUTHOK, "Proceed with negotiation.");
ssl_control_handshake(p_sess);
if (str_equal_text(&p_sess->ftp_arg_str, "SSL") ||
str_equal_text(&p_sess->ftp_arg_str, "TLS-P"))
{
p_sess->data_use_ssl = 1;
}
}
else
{
vsf_cmdio_write(p_sess, FTP_BADAUTH, "Unknown AUTH type.");
}
}
void
handle_pbsz(struct vsf_session* p_sess)
{
if (!p_sess->control_use_ssl)
{
vsf_cmdio_write(p_sess, FTP_BADPBSZ, "PBSZ needs a secure connection.");
}
else
{
vsf_cmdio_write(p_sess, FTP_PBSZOK, "PBSZ set to 0.");
}
}
void
handle_prot(struct vsf_session* p_sess)
{
str_upper(&p_sess->ftp_arg_str);
if (!p_sess->control_use_ssl)
{
vsf_cmdio_write(p_sess, FTP_BADPROT, "PROT needs a secure connection.");
}
else if (str_equal_text(&p_sess->ftp_arg_str, "C"))
{
p_sess->data_use_ssl = 0;
vsf_cmdio_write(p_sess, FTP_PROTOK, "PROT now Clear.");
}
else if (str_equal_text(&p_sess->ftp_arg_str, "P"))
{
p_sess->data_use_ssl = 1;
vsf_cmdio_write(p_sess, FTP_PROTOK, "PROT now Private.");
}
else if (str_equal_text(&p_sess->ftp_arg_str, "S") ||
str_equal_text(&p_sess->ftp_arg_str, "E"))
{
vsf_cmdio_write(p_sess, FTP_NOHANDLEPROT, "PROT not supported.");
}
else
{
vsf_cmdio_write(p_sess, FTP_NOSUCHPROT, "PROT not recognized.");
}
}
int
ssl_read(struct vsf_session* p_sess, void* p_ssl, char* p_buf, unsigned int len)
{
return ssl_read_common(p_sess, (SSL*) p_ssl, p_buf, len, SSL_read);
}
int
ssl_peek(struct vsf_session* p_sess, void* p_ssl, char* p_buf, unsigned int len)
{
return ssl_read_common(p_sess, (SSL*) p_ssl, p_buf, len, SSL_peek);
}
static int
ssl_read_common(struct vsf_session* p_sess,
SSL* p_void_ssl,
char* p_buf,
unsigned int len,
int (*p_ssl_func)(SSL*, void*, int))
{
int retval;
int err;
SSL* p_ssl = (SSL*) p_void_ssl;
do
{
retval = (*p_ssl_func)(p_ssl, p_buf, len);
err = SSL_get_error(p_ssl, retval);
}
while (retval < 0 && (err == SSL_ERROR_WANT_READ ||
err == SSL_ERROR_WANT_WRITE));
/* If we hit an EOF, make sure it was from the peer, not injected by the
* attacker.
*/
if (retval == 0 && SSL_get_shutdown(p_ssl) != SSL_RECEIVED_SHUTDOWN)
{
if (p_ssl == p_sess->p_control_ssl)
{
str_alloc_text(&debug_str, "Control");
}
else
{
str_alloc_text(&debug_str, "DATA");
}
str_append_text(&debug_str, " connection terminated without SSL shutdown.");
if (p_ssl != p_sess->p_control_ssl)
{
str_append_text(&debug_str,
" Buggy client! Integrity of upload cannot be asserted.");
}
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
if (tunable_strict_ssl_read_eof)
{
return -1;
}
}
return retval;
}
int
ssl_write(void* p_ssl, const char* p_buf, unsigned int len)
{
int retval;
int err;
do
{
retval = SSL_write((SSL*) p_ssl, p_buf, len);
err = SSL_get_error((SSL*) p_ssl, retval);
}
while (retval < 0 && (err == SSL_ERROR_WANT_READ ||
err == SSL_ERROR_WANT_WRITE));
return retval;
}
int
ssl_write_str(void* p_ssl, const struct mystr* p_str)
{
unsigned int len = str_getlen(p_str);
int ret = SSL_write((SSL*) p_ssl, str_getbuf(p_str), len);
if ((unsigned int) ret != len)
{
return -1;
}
return 0;
}
int
ssl_read_into_str(struct vsf_session* p_sess, void* p_ssl, struct mystr* p_str)
{
unsigned int len = str_getlen(p_str);
int ret = ssl_read(p_sess, p_ssl, (char*) str_getbuf(p_str), len);
if (ret >= 0)
{
str_trunc(p_str, (unsigned int) ret);
}
else
{
str_empty(p_str);
}
return ret;
}
static void
maybe_log_shutdown_state(struct vsf_session* p_sess)
{
if (tunable_debug_ssl)
{
int ret = SSL_get_shutdown(p_sess->p_data_ssl);
str_alloc_text(&debug_str, "SSL shutdown state is: ");
if (ret == 0)
{
str_append_text(&debug_str, "NONE");
}
else if (ret == SSL_SENT_SHUTDOWN)
{
str_append_text(&debug_str, "SSL_SENT_SHUTDOWN");
}
else if (ret == SSL_RECEIVED_SHUTDOWN)
{
str_append_text(&debug_str, "SSL_RECEIVED_SHUTDOWN");
}
else
{
str_append_ulong(&debug_str, ret);
}
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
}
static void
maybe_log_ssl_error_state(struct vsf_session* p_sess, int ret)
{
if (tunable_debug_ssl)
{
str_alloc_text(&debug_str, "SSL ret: ");
str_append_ulong(&debug_str, ret);
str_append_text(&debug_str, ", SSL error: ");
str_append_text(&debug_str, get_ssl_error());
str_append_text(&debug_str, ", errno: ");
str_append_ulong(&debug_str, errno);
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
}
int
ssl_data_close(struct vsf_session* p_sess)
{
int success = 1;
SSL* p_ssl = p_sess->p_data_ssl;
if (p_ssl)
{
int ret;
maybe_log_shutdown_state(p_sess);
/* Disable Nagle algorithm. We want the shutdown packet to be sent
* immediately, there's nothing coming after.
*/
vsf_sysutil_set_nodelay(SSL_get_fd(p_ssl));
/* This is a mess. Ideally, when we're the sender, we'd like to get to the
* SSL_RECEIVED_SHUTDOWN state to get a cryptographic guarantee that the
* peer received all the data and shut the connection down cleanly. It
* doesn't matter hugely apart from logging, but it's a nagging detail.
* Unfortunately, no FTP client I found was able to get sends into that
* state, so the best we can do is issue SSL_shutdown but not check the
* errors / returns. At least this enables the receiver to be sure of the
* integrity of the send in terms of unwanted truncation.
*/
ret = SSL_shutdown(p_ssl);
maybe_log_shutdown_state(p_sess);
if (ret == 0)
{
ret = SSL_shutdown(p_ssl);
maybe_log_shutdown_state(p_sess);
if (ret != 1)
{
if (tunable_strict_ssl_write_shutdown)
{
success = 0;
}
maybe_log_shutdown_state(p_sess);
maybe_log_ssl_error_state(p_sess, ret);
}
}
else if (ret < 0)
{
if (tunable_strict_ssl_write_shutdown)
{
success = 0;
}
maybe_log_ssl_error_state(p_sess, ret);
}
SSL_free(p_ssl);
p_sess->p_data_ssl = NULL;
}
return success;
}
int
ssl_accept(struct vsf_session* p_sess, int fd)
{
/* SECURITY: data SSL connections don't have any auth on them as part of the
* protocol. If a client sends an unfortunately optional client cert then
* we can check for a match between the control and data connections.
*/
SSL* p_ssl;
int reused;
if (p_sess->p_data_ssl != NULL)
{
die("p_data_ssl should be NULL.");
}
p_ssl = get_ssl(p_sess, fd);
if (p_ssl == NULL)
{
return 0;
}
p_sess->p_data_ssl = p_ssl;
setup_bio_callbacks(p_ssl);
reused = SSL_session_reused(p_ssl);
if (tunable_require_ssl_reuse && !reused)
{
str_alloc_text(&debug_str, "No SSL session reuse on data channel.");
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
ssl_data_close(p_sess);
return 0;
}
if (str_getlen(&p_sess->control_cert_digest) > 0)
{
static struct mystr data_cert_digest;
if (!ssl_cert_digest(p_ssl, p_sess, &data_cert_digest))
{
str_alloc_text(&debug_str, "Missing cert on data channel.");
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
ssl_data_close(p_sess);
return 0;
}
if (str_strcmp(&p_sess->control_cert_digest, &data_cert_digest))
{
str_alloc_text(&debug_str, "DIFFERENT cert on data channel.");
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
ssl_data_close(p_sess);
return 0;
}
if (tunable_debug_ssl)
{
str_alloc_text(&debug_str, "Matching cert on data channel.");
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
}
return 1;
}
void
ssl_comm_channel_init(struct vsf_session* p_sess)
{
const struct vsf_sysutil_socketpair_retval retval =
vsf_sysutil_unix_stream_socketpair();
if (p_sess->ssl_consumer_fd != -1)
{
bug("ssl_consumer_fd active");
}
if (p_sess->ssl_slave_fd != -1)
{
bug("ssl_slave_fd active");
}
p_sess->ssl_consumer_fd = retval.socket_one;
p_sess->ssl_slave_fd = retval.socket_two;
}
void
ssl_comm_channel_set_consumer_context(struct vsf_session* p_sess)
{
if (p_sess->ssl_slave_fd == -1)
{
bug("ssl_slave_fd already closed");
}
vsf_sysutil_close(p_sess->ssl_slave_fd);
p_sess->ssl_slave_fd = -1;
}
void
ssl_comm_channel_set_producer_context(struct vsf_session* p_sess)
{
if (p_sess->ssl_consumer_fd == -1)
{
bug("ssl_consumer_fd already closed");
}
vsf_sysutil_close(p_sess->ssl_consumer_fd);
p_sess->ssl_consumer_fd = -1;
}
static SSL*
get_ssl(struct vsf_session* p_sess, int fd)
{
SSL* p_ssl = SSL_new(p_sess->p_ssl_ctx);
if (p_ssl == NULL)
{
if (tunable_debug_ssl)
{
str_alloc_text(&debug_str, "SSL_new failed");
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
return NULL;
}
if (!SSL_set_fd(p_ssl, fd))
{
if (tunable_debug_ssl)
{
str_alloc_text(&debug_str, "SSL_set_fd failed");
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
SSL_free(p_ssl);
return NULL;
}
if (SSL_accept(p_ssl) != 1)
{
const char* p_err = get_ssl_error();
if (tunable_debug_ssl)
{
str_alloc_text(&debug_str, "SSL_accept failed: ");
str_append_text(&debug_str, p_err);
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
/* The RFC is quite clear that we can just close the control channel
* here.
*/
die(p_err);
}
if (tunable_debug_ssl)
{
const char* p_ssl_version = SSL_get_cipher_version(p_ssl);
const SSL_CIPHER* p_ssl_cipher = SSL_get_current_cipher(p_ssl);
const char* p_cipher_name = SSL_CIPHER_get_name(p_ssl_cipher);
X509* p_ssl_cert = SSL_get_peer_certificate(p_ssl);
int reused = SSL_session_reused(p_ssl);
str_alloc_text(&debug_str, "SSL version: ");
str_append_text(&debug_str, p_ssl_version);
str_append_text(&debug_str, ", SSL cipher: ");
str_append_text(&debug_str, p_cipher_name);
if (reused)
{
str_append_text(&debug_str, ", reused");
}
else
{
str_append_text(&debug_str, ", not reused");
}
if (p_ssl_cert != NULL)
{
str_append_text(&debug_str, ", CERT PRESENTED");
X509_free(p_ssl_cert);
}
else
{
str_append_text(&debug_str, ", no cert");
}
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
return p_ssl;
}
static int
ssl_session_init(struct vsf_session* p_sess)
{
SSL* p_ssl = get_ssl(p_sess, VSFTP_COMMAND_FD);
if (p_ssl == NULL)
{
return 0;
}
p_sess->p_control_ssl = p_ssl;
(void) ssl_cert_digest(p_ssl, p_sess, &p_sess->control_cert_digest);
setup_bio_callbacks(p_ssl);
return 1;
}
static int
ssl_cert_digest(SSL* p_ssl, struct vsf_session* p_sess, struct mystr* p_str)
{
X509* p_cert = SSL_get_peer_certificate(p_ssl);
unsigned int num_bytes = 0;
if (p_cert == NULL)
{
return 0;
}
str_reserve(p_str, EVP_MAX_MD_SIZE);
str_empty(p_str);
str_rpad(p_str, EVP_MAX_MD_SIZE);
if (!X509_digest(p_cert, EVP_sha256(), (unsigned char*) str_getbuf(p_str),
&num_bytes))
{
die("X509_digest failed");
}
X509_free(p_cert);
if (tunable_debug_ssl)
{
unsigned int i;
str_alloc_text(&debug_str, "Cert digest:");
for (i = 0; i < num_bytes; ++i)
{
str_append_char(&debug_str, ' ');
str_append_ulong(
&debug_str, (unsigned long) (unsigned char) str_get_char_at(p_str, i));
}
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
str_trunc(p_str, num_bytes);
return 1;
}
static char*
get_ssl_error()
{
SSL_load_error_strings();
return ERR_error_string(ERR_get_error(), NULL);
}
static void setup_bio_callbacks(SSL* p_ssl)
{
BIO* p_bio = SSL_get_rbio(p_ssl);
BIO_set_callback(p_bio, bio_callback);
p_bio = SSL_get_wbio(p_ssl);
BIO_set_callback(p_bio, bio_callback);
}
static long
bio_callback(
BIO* p_bio, int oper, const char* p_arg, int argi, long argl, long ret)
{
int retval = 0;
int fd = 0;
(void) p_arg;
(void) argi;
(void) argl;
if (oper == (BIO_CB_READ | BIO_CB_RETURN) ||
oper == (BIO_CB_WRITE | BIO_CB_RETURN))
{
retval = (int) ret;
fd = BIO_get_fd(p_bio, NULL);
}
vsf_sysutil_check_pending_actions(kVSFSysUtilIO, retval, fd);
return ret;
}
static int
ssl_verify_callback(int verify_ok, X509_STORE_CTX* p_ctx)
{
(void) p_ctx;
if (tunable_validate_cert)
{
return verify_ok;
}
return 1;
}
#define UNUSED(x) ( (void)(x) )
static DH *
ssl_tmp_dh_callback(SSL *ssl, int is_export, int keylength)
{
// strict compiler bypassing
UNUSED(ssl);
UNUSED(is_export);
return DH_get_dh(keylength);
}
static int
ssl_alpn_callback(SSL* p_ssl,
const unsigned char** p_out,
unsigned char* outlen,
const unsigned char* p_in,
unsigned int inlen,
void* p_arg) {
unsigned int i;
struct vsf_session* p_sess = (struct vsf_session*) p_arg;
int is_ok = 0;
(void) p_ssl;
/* Initialize just in case. */
*p_out = p_in;
*outlen = 0;
for (i = 0; i < inlen; ++i) {
unsigned int left = (inlen - i);
if (left < 4) {
continue;
}
if (p_in[i] == 3 && p_in[i + 1] == 'f' && p_in[i + 2] == 't' &&
p_in[i + 3] == 'p')
{
is_ok = 1;
*p_out = &p_in[i + 1];
*outlen = 3;
break;
}
}
if (!is_ok)
{
str_alloc_text(&debug_str, "ALPN rejection");
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
if (!is_ok || tunable_debug_ssl)
{
str_alloc_text(&debug_str, "ALPN data: ");
for (i = 0; i < inlen; ++i) {
str_append_char(&debug_str, p_in[i]);
}
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
if (is_ok)
{
return SSL_TLSEXT_ERR_OK;
}
else
{
return SSL_TLSEXT_ERR_ALERT_FATAL;
}
}
static long
ssl_sni_callback(SSL* p_ssl, int* p_al, void* p_arg)
{
static struct mystr s_sni_expected_hostname;
static struct mystr s_sni_received_hostname;
int servername_type;
const char* p_sni_servername;
struct vsf_session* p_sess = (struct vsf_session*) p_arg;
int is_ok = 0;
(void) p_ssl;
(void) p_arg;
if (tunable_ssl_sni_hostname)
{
str_alloc_text(&s_sni_expected_hostname, tunable_ssl_sni_hostname);
}
/* The OpenSSL documentation says it is pre-initialized like this, but set
* it just in case.
*/
*p_al = SSL_AD_UNRECOGNIZED_NAME;
servername_type = SSL_get_servername_type(p_ssl);
p_sni_servername = SSL_get_servername(p_ssl, TLSEXT_NAMETYPE_host_name);
if (p_sni_servername != NULL) {
str_alloc_text(&s_sni_received_hostname, p_sni_servername);
}
if (str_isempty(&s_sni_expected_hostname))
{
is_ok = 1;
}
else if (servername_type != TLSEXT_NAMETYPE_host_name)
{
/* Fail. */
str_alloc_text(&debug_str, "SNI bad type: ");
str_append_ulong(&debug_str, servername_type);
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
else
{
if (!str_strcmp(&s_sni_expected_hostname, &s_sni_received_hostname))
{
is_ok = 1;
}
else
{
str_alloc_text(&debug_str, "SNI rejection");
vsf_log_line(p_sess, kVSFLogEntryDebug, &debug_str);
}
}
if (!is_ok || tunable_debug_ssl)