easy-tls.c

Openssl 0.9.8e 最新版OpenSSL

    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;