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openssl/demos/easy_tls/easy-tls.c

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/* -*- Mode: C; c-file-style: "bsd" -*- */
/*
* easy-tls.c -- generic TLS proxy.
* $Id: easy-tls.c,v 1.4 2002/03/05 09:07:16 bodo Exp $
*/
/*
(c) Copyright 1999 Bodo Moeller. All rights reserved.
This is free software; you can redistributed and/or modify it
unter the terms of either
- the GNU General Public License as published by the
Free Software Foundation, version 1, or (at your option)
any later version,
or
- the following license:
*/
/*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that each of the following
* conditions is met:
*
* 1. Redistributions qualify as "freeware" or "Open Source Software" under
* one of the following terms:
*
* (a) Redistributions are made at no charge beyond the reasonable cost of
* materials and delivery.
*
* (b) Redistributions are accompanied by a copy of the Source Code
* or by an irrevocable offer to provide a copy of the Source Code
* for up to three years at the cost of materials and delivery.
* Such redistributions must allow further use, modification, and
* redistribution of the Source Code under substantially the same
* terms as this license.
*
* 2. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 3. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 4. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by Bodo Moeller."
* (If available, substitute umlauted o for oe.)
*
* 5. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by Bodo Moeller."
*
* THIS SOFTWARE IS PROVIDED BY BODO MOELLER ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BODO MOELLER OR
* HIS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Attribution for OpenSSL library:
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
* This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)
*/
static char const rcsid[] =
"$Id: easy-tls.c,v 1.4 2002/03/05 09:07:16 bodo Exp $";
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/utsname.h>
#include <unistd.h>
#include <openssl/crypto.h>
#include <openssl/dh.h>
#include <openssl/dsa.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/opensslv.h>
#include <openssl/pem.h>
#include <openssl/rand.h>
#ifndef NO_RSA
#include <openssl/rsa.h>
#endif
#include <openssl/ssl.h>
#include <openssl/x509.h>
#include <openssl/x509_vfy.h>
#if OPENSSL_VERSION_NUMBER < 0x00904000L /* 0.9.4-dev */
# error "This program needs OpenSSL 0.9.4 or later."
#endif
#include "easy-tls.h" /* include after <openssl/ssl.h> if both are needed */
#if TLS_INFO_SIZE > PIPE_BUF
# if PIPE_BUF < 512
# error "PIPE_BUF < 512" /* non-POSIX */
# endif
# error "TLS_INFO_SIZE > PIPE_BUF"
#endif
/*****************************************************************************/
#ifdef TLS_APP
# include TLS_APP
#endif
/* Applications can define:
* TLS_APP_PROCESS_INIT -- void ...(int fd, int client_p, void *apparg)
* TLS_CUMULATE_ERRORS
* TLS_ERROR_BUFSIZ
* TLS_APP_ERRFLUSH -- void ...(int child_p, char *, size_t, void *apparg)
*/
#ifndef TLS_APP_PROCESS_INIT
# define TLS_APP_PROCESS_INIT(fd, client_p, apparg) ((void) 0)
#endif
#ifndef TLS_ERROR_BUFSIZ
# define TLS_ERROR_BUFSIZ (10*160)
#endif
#if TLS_ERROR_BUFSIZ < 2 /* {'\n',0} */
# error "TLS_ERROR_BUFSIZE is too small."
#endif
#ifndef TLS_APP_ERRFLUSH
# define TLS_APP_ERRFLUSH tls_app_errflush
static void
tls_app_errflush(int child_p, char *errbuf, size_t num, void *apparg)
{
fputs(errbuf, stderr);
}
#endif
/*****************************************************************************/
#ifdef DEBUG_TLS
# define DEBUG_MSG(x) fprintf(stderr," %s\n",x)
# define DEBUG_MSG2(x,y) fprintf(stderr, " %s: %d\n",x,y)
static int tls_loop_count = 0;
static int tls_select_count = 0;
#else
# define DEBUG_MSG(x) (void)0
# define DEBUG_MSG2(x,y) (void)0
#endif
static void tls_rand_seed_uniquely(void);
static void tls_proxy(int clear_fd, int tls_fd, int info_fd, SSL_CTX *ctx, int client_p);
static int tls_socket_nonblocking(int fd);
static int tls_child_p = 0;
static void *tls_child_apparg;
struct tls_start_proxy_args
tls_start_proxy_defaultargs(void)
{
struct tls_start_proxy_args ret;
ret.fd = -1;
ret.client_p = -1;
ret.ctx = NULL;
ret.pid = NULL;
ret.infofd = NULL;
return ret;
}
/* Slice in TLS proxy process at fd.
* Return value:
* 0 ok (*pid is set to child's PID if pid != NULL),
* < 0 look at errno
* > 0 other error
* (return value encodes place of error)
*
*/
int
tls_start_proxy(struct tls_start_proxy_args a, void *apparg)
{
int fds[2] = {-1, -1};
int infofds[2] = {-1, -1};
int r, getfd, getfl;
int ret;
DEBUG_MSG2("tls_start_proxy fd", a.fd);
DEBUG_MSG2("tls_start_proxy client_p", a.client_p);
if (a.fd == -1 || a.client_p == -1 || a.ctx == NULL)
return 1;
if (a.pid != NULL) {
*a.pid = 0;
}
if (a.infofd != NULL) {
*a.infofd = -1;
}
r = socketpair(AF_UNIX, SOCK_STREAM, 0, fds);
if (r == -1)
return -1;
if (a.fd >= FD_SETSIZE || fds[0] >= FD_SETSIZE) {
ret = 2;
goto err;
}
if (a.infofd != NULL) {
r = pipe(infofds);
if (r == -1) {
ret = -3;
goto err;
}
}
r = fork();
if (r == -1) {
ret = -4;
goto err;
}
if (r == 0) {
DEBUG_MSG("fork");
tls_child_p = 1;
tls_child_apparg = apparg;
close(fds[1]);
if (infofds[0] != -1)
close(infofds[0]);
TLS_APP_PROCESS_INIT(a.fd, a.client_p, apparg);
DEBUG_MSG("TLS_APP_PROCESS_INIT");
tls_proxy(fds[0], a.fd, infofds[1], a.ctx, a.client_p);
exit(0);
}
if (a.pid != NULL)
*a.pid = r;
if (infofds[1] != -1) {
close(infofds[1]);
infofds[1] = -1;
}
/* install fds[1] in place of fd: */
close(fds[0]);
fds[0] = -1;
getfd = fcntl(a.fd, F_GETFD);
getfl = fcntl(a.fd, F_GETFL);
r = dup2(fds[1], a.fd);
close(fds[1]);
fds[1] = -1;
if (r == -1) {
ret = -5;
goto err;
}
if (getfd != 1)
fcntl(a.fd, F_SETFD, getfd);
if (getfl & O_NONBLOCK)
(void)tls_socket_nonblocking(a.fd);
if (a.infofd != NULL)
*a.infofd = infofds[0];
return 0;
err:
if (fds[0] != -1)
close(fds[0]);
if (fds[1] != -1)
close(fds[1]);
if (infofds[0] != -1)
close(infofds[0]);
if (infofds[1] != -1)
close(infofds[1]);
return ret;
}
/*****************************************************************************/
static char errbuf[TLS_ERROR_BUFSIZ];
static size_t errbuf_i = 0;
static void
tls_errflush(void *apparg)
{
if (errbuf_i == 0)
return;
assert(errbuf_i < sizeof errbuf);
assert(errbuf[errbuf_i] == 0);
if (errbuf_i == sizeof errbuf - 1) {
/* make sure we have a newline, even if string has been truncated */
errbuf[errbuf_i - 1] = '\n';
}
/* TLS_APP_ERRFLUSH may modify the string as needed,
* e.g. substitute other characters for \n for convenience */
TLS_APP_ERRFLUSH(tls_child_p, errbuf, errbuf_i, apparg);
errbuf_i = 0;
}
static void
tls_errprintf(int flush, void *apparg, const char *fmt, ...)
{
va_list args;
int r;
if (errbuf_i < sizeof errbuf - 1) {
size_t n;
va_start(args, fmt);
n = (sizeof errbuf) - errbuf_i;
r = vsnprintf(errbuf + errbuf_i, n, fmt, args);
if (r >= n)
r = n - 1;
if (r >= 0) {
errbuf_i += r;
} else {
errbuf_i = sizeof errbuf - 1;
errbuf[errbuf_i] = '\0';
}
assert(errbuf_i < sizeof errbuf);
assert(errbuf[errbuf_i] == 0);
}
#ifndef TLS_CUMULATE_ERRORS
tls_errflush(apparg);
#else
if (flush)
tls_errflush(apparg);
#endif
}
/* app_prefix.. are for additional information provided by caller.
* If OpenSSL error queue is empty, print default_text ("???" if NULL).
*/
static char *
tls_openssl_errors(const char *app_prefix_1, const char *app_prefix_2, const char *default_text, void *apparg)
{
static char reasons[255];
size_t reasons_i;
unsigned long err;
const char *file;
int line;
const char *data;
int flags;
char *errstring;
int printed_something = 0;
reasons_i = 0;
assert(app_prefix_1 != NULL);
assert(app_prefix_2 != NULL);
if (default_text == NULL)
default_text = "?""?""?";
while ((err = ERR_get_error_line_data(&file,&line,&data,&flags)) != 0) {
if (reasons_i < sizeof reasons) {
size_t n;
int r;
n = (sizeof reasons) - reasons_i;
r = snprintf(reasons + reasons_i, n, "%s%s", (reasons_i > 0 ? ", " : ""), ERR_reason_error_string(err));
if (r >= n)
r = n - 1;
if (r >= 0) {
reasons_i += r;
} else {
reasons_i = sizeof reasons;
}
assert(reasons_i <= sizeof reasons);
}
errstring = ERR_error_string(err, NULL);
assert(errstring != NULL);
tls_errprintf(0, apparg, "OpenSSL error%s%s: %s:%s:%d:%s\n", app_prefix_1, app_prefix_2, errstring, file, line, (flags & ERR_TXT_STRING) ? data : "");
printed_something = 1;
}
if (!printed_something) {
assert(reasons_i == 0);
snprintf(reasons, sizeof reasons, "%s", default_text);
tls_errprintf(0, apparg, "OpenSSL error%s%s: %s\n", app_prefix_1, app_prefix_2, default_text);
}
#ifdef TLS_CUMULATE_ERRORS
tls_errflush(apparg);
#endif
assert(errbuf_i == 0);
return reasons;
}
/*****************************************************************************/
static int tls_init_done = 0;
static int
tls_init(void *apparg)
{
if (tls_init_done)
return 0;
SSL_load_error_strings();
if (!SSL_library_init() /* aka SSLeay_add_ssl_algorithms() */ ) {
tls_errprintf(1, apparg, "SSL_library_init failed.\n");
return -1;
}
tls_init_done = 1;
tls_rand_seed();
return 0;
}
/*****************************************************************************/
static void
tls_rand_seed_uniquely(void)
{
struct {
pid_t pid;
time_t time;
void *stack;
} data;
data.pid = getpid();
data.time = time(NULL);
data.stack = (void *)&data;
RAND_seed((const void *)&data, sizeof data);
}
void
tls_rand_seed(void)
{
struct {
struct utsname uname;
int uname_1;
int uname_2;
uid_t uid;
uid_t euid;
gid_t gid;
gid_t egid;
} data;
data.uname_1 = uname(&data.uname);
data.uname_2 = errno; /* Let's hope that uname fails randomly :-) */
data.uid = getuid();
data.euid = geteuid();
data.gid = getgid();
data.egid = getegid();
RAND_seed((const void *)&data, sizeof data);
tls_rand_seed_uniquely();
}
static int tls_rand_seeded_p = 0;
#define my_MIN_SEED_BYTES 256 /* struct stat can be larger than 128 */
int
tls_rand_seed_from_file(const char *filename, size_t n, void *apparg)
{
/* Seed OpenSSL's random number generator from file.
Try to read n bytes if n > 0, whole file if n == 0. */
int r;
if (tls_init(apparg) == -1)
return -1;
tls_rand_seed();
r = RAND_load_file(filename, (n > 0 && n < LONG_MAX) ? (long)n : LONG_MAX);
/* r is the number of bytes filled into the random number generator,
* which are taken from "stat(filename, ...)" in addition to the
* file contents.
*/
assert(1 < my_MIN_SEED_BYTES);
/* We need to detect at least those cases when the file does not exist
* at all. With current versions of OpenSSL, this should do it: */
if (n == 0)
n = my_MIN_SEED_BYTES;
if (r < n) {
tls_errprintf(1, apparg, "rand_seed_from_file: could not read %d bytes from %s.\n", n, filename);
return -1;
} else {
tls_rand_seeded_p = 1;
return 0;
}
}
void
tls_rand_seed_from_memory(const void *buf, size_t n)
{
size_t i = 0;
while (i < n) {
size_t rest = n - i;
int chunk = rest < INT_MAX ? (int)rest : INT_MAX;
RAND_seed((const char *)buf + i, chunk);
i += chunk;
}
tls_rand_seeded_p = 1;
}
/*****************************************************************************/
struct tls_x509_name_string {
char str[100];
};
static void
tls_get_x509_subject_name_oneline(X509 *cert, struct tls_x509_name_string *namestring)
{
X509_NAME *name;
if (cert == NULL) {
namestring->str[0] = '\0';
return;
}
name = X509_get_subject_name(cert); /* does not increment any reference counter */
assert(sizeof namestring->str >= 4); /* "?" or "...", plus 0 */
if (name == NULL) {
namestring->str[0] = '?';
namestring->str[1] = 0;
} else {
size_t len;
X509_NAME_oneline(name, namestring->str, sizeof namestring->str);
len = strlen(namestring->str);
assert(namestring->str[len] == 0);
assert(len < sizeof namestring->str);
if (len+1 == sizeof namestring->str) {
/* (Probably something was cut off.)
* Does not really work -- X509_NAME_oneline truncates after
* name components, we cannot tell from the result whether
* anything is missing. */
assert(namestring->str[len] == 0);
namestring->str[--len] = '.';
namestring->str[--len] = '.';
namestring->str[--len] = '.';
}
}
}
/*****************************************************************************/
/* to hinder OpenSSL from asking for passphrases */
static int
no_passphrase_callback(char *buf, int num, int w, void *arg)
{
return -1;
}
#if OPENSSL_VERSION_NUMBER >= 0x00907000L
static int
verify_dont_fail_cb(X509_STORE_CTX *c, void *unused_arg)
#else
static int
verify_dont_fail_cb(X509_STORE_CTX *c)
#endif
{
int i;
i = X509_verify_cert(c); /* sets c->error */
#if OPENSSL_VERSION_NUMBER >= 0x00905000L /* don't allow unverified
* certificates -- they could
* survive session reuse, but
* OpenSSL < 0.9.5-dev does not
* preserve their verify_result */
if (i == 0)
return 1;
else
#endif
return i;
}
static DH *tls_dhe1024 = NULL; /* generating these takes a while, so do it just once */
void
tls_set_dhe1024(int i, void *apparg)
{
DSA *dsaparams;
DH *dhparams;
const char *seed[] = { ";-) :-( :-) :-( ",
";-) :-( :-) :-( ",
"Random String no. 12",
";-) :-( :-) :-( ",
"hackers have even mo", /* from jargon file */
};
unsigned char seedbuf[20];
tls_init(apparg);
if (i >= 0) {
i %= sizeof seed / sizeof seed[0];
assert(strlen(seed[i]) == 20);
memcpy(seedbuf, seed[i], 20);
dsaparams = DSA_generate_parameters(1024, seedbuf, 20, NULL, NULL, 0, NULL);
} else {
/* random parameters (may take a while) */
dsaparams = DSA_generate_parameters(1024, NULL, 0, NULL, NULL, 0, NULL);
}
if (dsaparams == NULL) {
tls_openssl_errors("", "", NULL, apparg);
return;
}
dhparams = DSA_dup_DH(dsaparams);
DSA_free(dsaparams);
if (dhparams == NULL) {
tls_openssl_errors("", "", NULL, apparg);
return;
}
if (tls_dhe1024 != NULL)
DH_free(tls_dhe1024);
tls_dhe1024 = dhparams;
}
struct tls_create_ctx_args
tls_create_ctx_defaultargs(void)
{
struct tls_create_ctx_args ret;
ret.client_p = 0;
ret.certificate_file = NULL;
ret.key_file = NULL;
ret.ca_file = NULL;
ret.verify_depth = -1;
ret.fail_unless_verified = 0;
ret.export_p = 0;
return ret;
}
SSL_CTX *
tls_create_ctx(struct tls_create_ctx_args a, void *apparg)
{
int r;
static long context_num = 0;
SSL_CTX *ret;
const char *err_pref_1 = "", *err_pref_2 = "";
if (tls_init(apparg) == -1)
return NULL;
ret = SSL_CTX_new((a.client_p? SSLv23_client_method:SSLv23_server_method)());
if (ret == NULL)
goto err;
SSL_CTX_set_default_passwd_cb(ret, no_passphrase_callback);
SSL_CTX_set_mode(ret, SSL_MODE_ENABLE_PARTIAL_WRITE);
if ((a.certificate_file != NULL) || (a.key_file != NULL)) {
if (a.key_file == NULL) {
tls_errprintf(1, apparg, "Need a key file.\n");
goto err_return;
}
if (a.certificate_file == NULL) {
tls_errprintf(1, apparg, "Need a certificate chain file.\n");
goto err_return;
}
if (!SSL_CTX_use_PrivateKey_file(ret, a.key_file, SSL_FILETYPE_PEM))
goto err;
if (!tls_rand_seeded_p) {
/* particularly paranoid people may not like this --
* so provide your own random seeding before calling this */
if (tls_rand_seed_from_file(a.key_file, 0, apparg) == -1)
goto err_return;
}
if (!SSL_CTX_use_certificate_chain_file(ret, a.certificate_file))
goto err;
if (!SSL_CTX_check_private_key(ret)) {
tls_errprintf(1, apparg, "Private key \"%s\" does not match certificate \"%s\".\n", a.key_file, a.certificate_file);
goto err_peek;
}
}
if ((a.ca_file != NULL) || (a.verify_depth > 0)) {
context_num++;
r = SSL_CTX_set_session_id_context(ret, (const void *)&context_num, (unsigned int)sizeof context_num);
if (!r)
goto err;
SSL_CTX_set_verify(ret, SSL_VERIFY_PEER | (a.fail_unless_verified ? SSL_VERIFY_FAIL_IF_NO_PEER_CERT : 0), 0);
if (!a.fail_unless_verified)
SSL_CTX_set_cert_verify_callback(ret, verify_dont_fail_cb, NULL);
if (a.verify_depth > 0)
SSL_CTX_set_verify_depth(ret, a.verify_depth);
if (a.ca_file != NULL) {
r = SSL_CTX_load_verify_locations(ret, a.ca_file, NULL /* no CA-directory */); /* does not report failure if file does not exist ... */
if (!r) {
err_pref_1 = " while processing certificate file ";
err_pref_2 = a.ca_file;
goto err;
}
if (!a.client_p) {
/* SSL_load_client_CA_file is a misnomer, it just creates a list of CNs. */
SSL_CTX_set_client_CA_list(ret, SSL_load_client_CA_file(a.ca_file));
/* SSL_CTX_set_client_CA_list does not have a return value;
* it does not really need one, but make sure
* (we really test if SSL_load_client_CA_file worked) */
if (SSL_CTX_get_client_CA_list(ret) == NULL) {
tls_errprintf(1, apparg, "Could not set client CA list from \"%s\".\n", a.ca_file);
goto err_peek;
}
}
}
}
if (!a.client_p) {
if (tls_dhe1024 == NULL) {
int i;
RAND_bytes((unsigned char *) &i, sizeof i);
/* make sure that i is non-negative -- pick one of the provided
* seeds */
if (i < 0)
i = -i;
if (i < 0)
i = 0;
tls_set_dhe1024(i, apparg);
if (tls_dhe1024 == NULL)
goto err_return;
}
if (!SSL_CTX_set_tmp_dh(ret, tls_dhe1024))
goto err;
/* avoid small subgroup attacks: */
SSL_CTX_set_options(ret, SSL_OP_SINGLE_DH_USE);
}
#ifndef NO_RSA
if (!a.client_p && a.export_p) {
RSA *tmpkey;
tmpkey = RSA_generate_key(512, RSA_F4, 0, NULL);
if (tmpkey == NULL)
goto err;
if (!SSL_CTX_set_tmp_rsa(ret, tmpkey)) {
RSA_free(tmpkey);
goto err;
}
RSA_free(tmpkey); /* SSL_CTX_set_tmp_rsa uses a duplicate. */
}
#endif
return ret;
err_peek:
if (!ERR_peek_error())
goto err_return;
err:
tls_openssl_errors(err_pref_1, err_pref_2, NULL, apparg);
err_return:
if (ret != NULL)
SSL_CTX_free(ret);
return NULL;
}
/*****************************************************************************/
static int
tls_socket_nonblocking(int fd)
{
int v, r;
v = fcntl(fd, F_GETFL, 0);
if (v == -1) {
if (errno == EINVAL)
return 0; /* already shut down -- ignore */
return -1;
}
r = fcntl(fd, F_SETFL, v | O_NONBLOCK);
if (r == -1) {
if (errno == EINVAL)
return 0; /* already shut down -- ignore */
return -1;
}
return 0;
}
static int
max(int a, int b)
{
return a > b ? a : b;
}
static void
tls_sockets_select(int read_select_1, int read_select_2, int write_select_1, int write_select_2, int seconds /* timeout, -1 means no timeout */)
{
int maxfd, n;
fd_set reads, writes;
struct timeval timeout;
struct timeval *timeout_p;
assert(read_select_1 >= -1 && read_select_2 >= -1 && write_select_1 >= -1 && write_select_2 >= -1);
assert(read_select_1 < FD_SETSIZE && read_select_2 < FD_SETSIZE -1 && write_select_1 < FD_SETSIZE -1 && write_select_2 < FD_SETSIZE -1);
maxfd = max(max(read_select_1, read_select_2), max(write_select_1, write_select_2));
assert(maxfd >= 0);
FD_ZERO(&reads);
FD_ZERO(&writes);
for(n = 0; n < 4; ++n) {
int i = n % 2;
int w = n >= 2;
/* loop over all (i, w) in {0,1}x{0,1} */
int fd;
if (i == 0 && w == 0)
fd = read_select_1;
else if (i == 1 && w == 0)
fd = read_select_2;
else if (i == 0 && w == 1)
fd = write_select_1;
else {
assert(i == 1 && w == 1);
fd = write_select_2;
}
if (fd >= 0) {
if (w == 0)
FD_SET(fd, &reads);
else /* w == 1 */
FD_SET(fd, &writes);
}
}
if (seconds >= 0) {
timeout.tv_sec = seconds;
timeout.tv_usec = 0;
timeout_p = &timeout;
} else
timeout_p = NULL;
DEBUG_MSG2("select no.", ++tls_select_count);
select(maxfd + 1, &reads, &writes, (fd_set *) NULL, timeout_p);
DEBUG_MSG("cont.");
}
/*****************************************************************************/
#define TUNNELBUFSIZE (16*1024)
struct tunnelbuf {
char buf[TUNNELBUFSIZE];
size_t len;
size_t offset;
};
static int tls_connect_attempt(SSL *, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref);
static int tls_accept_attempt(SSL *, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref);
static int tls_write_attempt(SSL *, struct tunnelbuf *, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref);
static int tls_read_attempt(SSL *, struct tunnelbuf *, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref);
static int write_attempt(int fd, struct tunnelbuf *, int *select, int *closed, int *progress);
static int read_attempt(int fd, struct tunnelbuf *, int *select, int *closed, int *progress);
static void write_info(SSL *ssl, int *info_fd)
{
if (*info_fd != -1) {
long v;
int v_ok;
struct tls_x509_name_string peer;
char infobuf[TLS_INFO_SIZE];
int r;
DEBUG_MSG("write_info");
v = SSL_get_verify_result(ssl);
v_ok = (v == X509_V_OK) ? 'A' : 'E'; /* Auth./Error */
{
X509 *peercert;
peercert = SSL_get_peer_certificate(ssl);
tls_get_x509_subject_name_oneline(peercert, &peer);
if (peercert != NULL)
X509_free(peercert);
}
if (peer.str[0] == '\0')
v_ok = '0'; /* no cert at all */
else
if (strchr(peer.str, '\n')) {
/* should not happen, but make sure */
*strchr(peer.str, '\n') = '\0';
}
r = snprintf(infobuf, sizeof infobuf, "%c:%s\n%s\n", v_ok, X509_verify_cert_error_string(v), peer.str);
DEBUG_MSG2("snprintf", r);
if (r == -1 || r >= sizeof infobuf)
r = sizeof infobuf - 1;
write(*info_fd, infobuf, r);
close (*info_fd);
*info_fd = -1;
}
}
/* tls_proxy expects that all fds are closed after return */
static void
tls_proxy(int clear_fd, int tls_fd, int info_fd, SSL_CTX *ctx, int client_p)
{
struct tunnelbuf clear_to_tls, tls_to_clear;
SSL *ssl;
BIO *rbio, *wbio;
int closed, in_handshake;
const char *err_pref_1 = "", *err_pref_2 = "";
const char *err_def = NULL;
assert(clear_fd != -1);
assert(tls_fd != -1);
assert(clear_fd < FD_SETSIZE);
assert(tls_fd < FD_SETSIZE);
/* info_fd may be -1 */
assert(ctx != NULL);
tls_rand_seed_uniquely();
tls_socket_nonblocking(clear_fd);
DEBUG_MSG2("clear_fd", clear_fd);
tls_socket_nonblocking(tls_fd);
DEBUG_MSG2("tls_fd", tls_fd);
ssl = SSL_new(ctx);
if (ssl == NULL)
goto err;
DEBUG_MSG("SSL_new");
if (!SSL_set_fd(ssl, tls_fd))
goto err;
rbio = SSL_get_rbio(ssl);
wbio = SSL_get_wbio(ssl); /* should be the same, but who cares */
assert(rbio != NULL);
assert(wbio != NULL);
if (client_p)
SSL_set_connect_state(ssl);
else
SSL_set_accept_state(ssl);
closed = 0;
in_handshake = 1;
tls_to_clear.len = 0;
tls_to_clear.offset = 0;
clear_to_tls.len = 0;
clear_to_tls.offset = 0;
err_def = "I/O error";
/* loop finishes as soon as we detect that one side closed;
* when all (program and OS) buffers have enough space,
* the data from the last succesful read in each direction is transferred
* before close */
do {
int clear_read_select = 0, clear_write_select = 0,
tls_read_select = 0, tls_write_select = 0,
progress = 0;
int r;
unsigned long num_read = BIO_number_read(rbio),
num_written = BIO_number_written(wbio);
DEBUG_MSG2("loop iteration", ++tls_loop_count);
if (in_handshake) {
DEBUG_MSG("in_handshake");
if (client_p)
r = tls_connect_attempt(ssl, &tls_write_select, &tls_read_select, &closed, &progress, &err_pref_1);
else
r = tls_accept_attempt(ssl, &tls_write_select, &tls_read_select, &closed, &progress, &err_pref_1);
if (r != 0) {
write_info(ssl, &info_fd);
goto err;
}
if (closed)
goto err_return;
if (!SSL_in_init(ssl)) {
in_handshake = 0;
write_info(ssl, &info_fd);
}
}
if (clear_to_tls.len != 0 && !in_handshake) {
assert(!closed);
r = tls_write_attempt(ssl, &clear_to_tls, &tls_write_select, &tls_read_select, &closed, &progress, &err_pref_1);
if (r != 0)
goto err;
if (closed) {
assert(progress);
tls_to_clear.offset = 0;
tls_to_clear.len = 0;
}
}
if (tls_to_clear.len != 0) {
assert(!closed);
r = write_attempt(clear_fd, &tls_to_clear, &clear_write_select, &closed, &progress);
if (r != 0)
goto err_return;
if (closed) {
assert(progress);
clear_to_tls.offset = 0;
clear_to_tls.len = 0;
}
}
if (!closed) {
if (clear_to_tls.offset + clear_to_tls.len < sizeof clear_to_tls.buf) {
r = read_attempt(clear_fd, &clear_to_tls, &clear_read_select, &closed, &progress);
if (r != 0)
goto err_return;
if (closed) {
r = SSL_shutdown(ssl);
DEBUG_MSG2("SSL_shutdown", r);
}
}
}
if (!closed && !in_handshake) {
if (tls_to_clear.offset + tls_to_clear.len < sizeof tls_to_clear.buf) {
r = tls_read_attempt(ssl, &tls_to_clear, &tls_write_select, &tls_read_select, &closed, &progress, &err_pref_1);
if (r != 0)
goto err;
if (closed) {
r = SSL_shutdown(ssl);
DEBUG_MSG2("SSL_shutdown", r);
}
}
}
if (!progress) {
DEBUG_MSG("!progress?");
if (num_read != BIO_number_read(rbio) || num_written != BIO_number_written(wbio))
progress = 1;
if (!progress) {
DEBUG_MSG("!progress");
assert(clear_read_select || tls_read_select || clear_write_select || tls_write_select);
tls_sockets_select(clear_read_select ? clear_fd : -1, tls_read_select ? tls_fd : -1, clear_write_select ? clear_fd : -1, tls_write_select ? tls_fd : -1, -1);
}
}
} while (!closed);
return;
err:
tls_openssl_errors(err_pref_1, err_pref_2, err_def, tls_child_apparg);
err_return:
return;
}
static int
tls_get_error(SSL *ssl, int r, int *write_select, int *read_select, int *closed, int *progress)
{
int err = SSL_get_error(ssl, r);
if (err == SSL_ERROR_NONE) {
assert(r > 0);
*progress = 1;
return 0;
}
assert(r <= 0);
switch (err) {
case SSL_ERROR_ZERO_RETURN:
assert(r == 0);
*closed = 1;
*progress = 1;
return 0;
case SSL_ERROR_WANT_WRITE:
*write_select = 1;
return 0;
case SSL_ERROR_WANT_READ:
*read_select = 1;
return 0;
}
return -1;
}
static int
tls_connect_attempt(SSL *ssl, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref)
{
int n, r;
DEBUG_MSG("tls_connect_attempt");
n = SSL_connect(ssl);
DEBUG_MSG2("SSL_connect",n);
r = tls_get_error(ssl, n, write_select, read_select, closed, progress);
if (r == -1)
*err_pref = " during SSL_connect";
return r;
}
static int
tls_accept_attempt(SSL *ssl, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref)
{
int n, r;
DEBUG_MSG("tls_accept_attempt");
n = SSL_accept(ssl);
DEBUG_MSG2("SSL_accept",n);
r = tls_get_error(ssl, n, write_select, read_select, closed, progress);
if (r == -1)
*err_pref = " during SSL_accept";
return r;
}
static int
tls_write_attempt(SSL *ssl, struct tunnelbuf *buf, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref)
{
int n, r;
DEBUG_MSG("tls_write_attempt");
n = SSL_write(ssl, buf->buf + buf->offset, buf->len);
DEBUG_MSG2("SSL_write",n);
r = tls_get_error(ssl, n, write_select, read_select, closed, progress);
if (n > 0) {
buf->len -= n;
assert(buf->len >= 0);
if (buf->len == 0)
buf->offset = 0;
else
buf->offset += n;
}
if (r == -1)
*err_pref = " during SSL_write";
return r;
}
static int
tls_read_attempt(SSL *ssl, struct tunnelbuf *buf, int *write_select, int *read_select, int *closed, int *progress, const char **err_pref)
{
int n, r;
size_t total;
DEBUG_MSG("tls_read_attempt");
total = buf->offset + buf->len;
assert(total < sizeof buf->buf);
n = SSL_read(ssl, buf->buf + total, (sizeof buf->buf) - total);
DEBUG_MSG2("SSL_read",n);
r = tls_get_error(ssl, n, write_select, read_select, closed, progress);
if (n > 0) {
buf->len += n;
assert(buf->offset + buf->len <= sizeof buf->buf);
}
if (r == -1)
*err_pref = " during SSL_read";
return r;
}
static int
get_error(int r, int *select, int *closed, int *progress)
{
if (r >= 0) {
*progress = 1;
if (r == 0)
*closed = 1;
return 0;
} else {
assert(r == -1);
if (errno == EAGAIN || errno == EWOULDBLOCK) {
*select = 1;
return 0;
} else if (errno == EPIPE) {
*progress = 1;
*closed = 1;
return 0;
} else
return -1;
}
}
static int write_attempt(int fd, struct tunnelbuf *buf, int *select, int *closed, int *progress)
{
int n, r;
DEBUG_MSG("write_attempt");
n = write(fd, buf->buf + buf->offset, buf->len);
DEBUG_MSG2("write",n);
r = get_error(n, select, closed, progress);
if (n > 0) {
buf->len -= n;
assert(buf->len >= 0);
if (buf->len == 0)
buf->offset = 0;
else
buf->offset += n;
}
if (r == -1)
tls_errprintf(1, tls_child_apparg, "write error: %s\n", strerror(errno));
return r;
}
static int
read_attempt(int fd, struct tunnelbuf *buf, int *select, int *closed, int *progress)
{
int n, r;
size_t total;
DEBUG_MSG("read_attempt");
total = buf->offset + buf->len;
assert(total < sizeof buf->buf);
n = read(fd, buf->buf + total, (sizeof buf->buf) - total);
DEBUG_MSG2("read",n);
r = get_error(n, select, closed, progress);
if (n > 0) {
buf->len += n;
assert(buf->offset + buf->len <= sizeof buf->buf);
}
if (r == -1)
tls_errprintf(1, tls_child_apparg, "read error: %s\n", strerror(errno));
return r;
}
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