Your IP : 216.73.216.224
/*
* tls.c -- handles:
* TLS support functions
* Certificate handling
* OpenSSL initialization and shutdown
*/
/*
* Written by Rumen Stoyanov <pseudo@egg6.net>
*
* Copyright (C) 2010 - 2019 Eggheads Development Team
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "main.h"
#ifdef TLS
#include <openssl/err.h>
#include <openssl/rand.h>
#include <openssl/x509v3.h>
extern int tls_vfydcc;
extern struct dcc_t *dcc;
int tls_maxdepth = 9; /* Max certificate chain verification depth */
int ssl_files_loaded = 0; /* Check for loaded SSL key/cert files */
SSL_CTX *ssl_ctx = NULL; /* SSL context object */
char *tls_randfile = NULL; /* Random seed file for SSL */
char tls_capath[121] = ""; /* Path to trusted CA certificates */
char tls_cafile[121] = ""; /* File containing trusted CA certificates */
char tls_certfile[121] = ""; /* Our own digital certificate ;) */
char tls_keyfile[121] = ""; /* Private key for use with eggdrop */
char tls_ciphers[2049] = ""; /* A list of ciphers for SSL to use */
/* Count allocated memory for SSL. This excludes memory allocated by OpenSSL's
* family of malloc functions.
*/
int expmem_tls()
{
int i, tot;
struct threaddata *td = threaddata();
/* currently it's only the appdata structs allocated by ssl_handshake() */
for (i = 0, tot = 0; i < td->MAXSOCKS; i++)
if (!(td->socklist[i].flags & (SOCK_UNUSED | SOCK_TCL)))
if (td->socklist[i].ssl && SSL_get_app_data(td->socklist[i].ssl))
tot += sizeof(ssl_appdata);
return tot;
}
/* Seeds the PRNG
*
* Only does something if the system doesn't have enough entropy.
* If there is no random file, one will be created either at
* $RANDFILE if set or at $HOME/.rnd
*
* Return value: 0 on success, !=0 on failure.
*/
static int ssl_seed(void)
{
char stackdata[1024];
static char rand_file[120];
FILE *fh;
#ifdef HAVE_RAND_STATUS
if (RAND_status())
return 0; /* Status OK */
#endif
/* If '/dev/urandom' is present, OpenSSL will use it by default.
* Otherwise we'll have to generate pseudorandom data ourselves,
* using system time, our process ID and some uninitialized static
* storage.
*/
if ((fh = fopen("/dev/urandom", "r"))) {
fclose(fh);
return 0;
}
if (RAND_file_name(rand_file, sizeof(rand_file)))
tls_randfile = rand_file;
else
return 1;
if (!RAND_load_file(rand_file, -1)) {
/* generate some pseudo random data */
unsigned int c;
c = time(NULL);
RAND_seed(&c, sizeof(c));
c = getpid();
RAND_seed(&c, sizeof(c));
RAND_seed(stackdata, sizeof(stackdata));
}
#ifdef HAVE_RAND_STATUS
if (!RAND_status())
return 2; /* pseudo random data still not enough */
#endif
return 0;
}
/* Prepares and initializes SSL stuff
*
* Creates a context object, supporting SSLv2/v3 & TLSv1 protocols;
* Seeds the Pseudo Random Number Generator;
* Optionally loads a SSL certifate and a private key.
* Tell OpenSSL the location of certificate authority certs
*
* Return value: 0 on successful initialization, !=0 on failure
*/
int ssl_init()
{
/* Load SSL and crypto error strings; register SSL algorithms */
SSL_load_error_strings();
SSL_library_init();
if (ssl_seed()) {
putlog(LOG_MISC, "*", "ERROR: TLS: unable to seed PRNG. Disabling SSL");
ERR_free_strings();
return -2;
}
/* A TLS/SSL connection established with this method will understand all
supported protocols (SSLv2, SSLv3, and TLSv1) */
if (!(ssl_ctx = SSL_CTX_new(SSLv23_method()))) {
putlog(LOG_MISC, "*", ERR_error_string(ERR_get_error(), NULL));
putlog(LOG_MISC, "*", "ERROR: TLS: unable to create context. Disabling SSL.");
ERR_free_strings();
return -1;
}
ssl_files_loaded = 0;
if ((tls_certfile[0] == '\0') != (tls_keyfile[0] == '\0')) {
/* Both need to be set or unset */
putlog(LOG_MISC, "*", "ERROR: TLS: %s set but %s unset. Both must be set "
"to use a certificate, or unset both to disable.",
tls_certfile[0] ? "ssl-certificate" : "ssl-privatekey",
tls_certfile[0] ? "ssl-privatekey" : "ssl-certificate");
fatal("ssl-privatekey and ssl-certificate must both be set or unset.", 0);
}
if (tls_certfile[0] && tls_keyfile[0]) {
/* Load our own certificate and private key. Mandatory for acting as
server, because we don't support anonymous ciphers by default. */
if (SSL_CTX_use_certificate_chain_file(ssl_ctx, tls_certfile) != 1) {
putlog(LOG_MISC, "*", "ERROR: TLS: unable to load own certificate from %s: %s",
tls_certfile, ERR_error_string(ERR_get_error(), NULL));
fatal("Unable to load TLS certificate (ssl-certificate config setting)!", 0);
}
if (SSL_CTX_use_PrivateKey_file(ssl_ctx, tls_keyfile, SSL_FILETYPE_PEM) != 1) {
putlog(LOG_MISC, "*", "ERROR: TLS: unable to load private key from %s: %s",
tls_keyfile, ERR_error_string(ERR_get_error(), NULL));
fatal("Unable to load TLS private key (ssl-privatekey config setting)!", 0);
}
ssl_files_loaded = 1;
}
if ((tls_capath[0] || tls_cafile[0]) &&
!SSL_CTX_load_verify_locations(ssl_ctx, tls_cafile[0] ? tls_cafile : NULL,
tls_capath[0] ? tls_capath : NULL)) {
putlog(LOG_MISC, "*", "ERROR: TLS: unable to set CA certificates location: %s",
ERR_error_string(ERR_get_error(), NULL));
ERR_free_strings();
}
/* Let advanced users specify the list of allowed ssl ciphers */
if (tls_ciphers[0] && !SSL_CTX_set_cipher_list(ssl_ctx, tls_ciphers)) {
/* this replaces any preset ciphers so an invalid list is fatal */
putlog(LOG_MISC, "*", "ERROR: TLS: no valid ciphers found. Disabling SSL.");
ERR_free_strings();
SSL_CTX_free(ssl_ctx);
ssl_ctx = NULL;
return -3;
}
return 0;
}
/* Free the SSL CTX, clean up the mess */
void ssl_cleanup()
{
if (ssl_ctx) {
SSL_CTX_free(ssl_ctx);
ssl_ctx = NULL;
}
if (tls_randfile)
RAND_write_file(tls_randfile);
ERR_free_strings();
}
char *ssl_fpconv(char *in, char *out)
{
long len;
char *fp;
unsigned char *md5;
if (!in)
return NULL;
if ((md5 = OPENSSL_hexstr2buf(in, &len))) {
fp = OPENSSL_buf2hexstr(md5, len);
if (fp) {
out = user_realloc(out, strlen(fp) + 1);
strcpy(out, fp);
OPENSSL_free(md5);
OPENSSL_free(fp);
return out;
}
OPENSSL_free(md5);
}
return NULL;
}
/* Get the certificate, corresponding to the connection
* identified by sock.
*
* Return value: pointer to a X509 certificate or NULL if we couldn't
* look up the certificate.
*/
static X509 *ssl_getcert(int sock)
{
int i;
struct threaddata *td = threaddata();
i = findsock(sock);
if (i == -1 || !td->socklist[i].ssl)
return NULL;
return SSL_get_peer_certificate(td->socklist[i].ssl);
}
/* Get the certificate fingerprint of the connection corresponding
* to the socket.
*
* Return value: ptr to the hexadecimal representation of the fingerprint
* or NULL if there's no certificate associated with the connection.
*/
char *ssl_getfp(int sock)
{
char *p;
unsigned int i;
X509 *cert;
static char fp[64];
unsigned char md[EVP_MAX_MD_SIZE];
if (!(cert = ssl_getcert(sock)))
return NULL;
if (!X509_digest(cert, EVP_sha1(), md, &i))
return NULL;
if (!(p = OPENSSL_buf2hexstr(md, i)))
return NULL;
strlcpy(fp, p, sizeof fp);
OPENSSL_free(p);
return fp;
}
/* Get the UID field from the certificate subject name.
* The certificate is looked up using the socket of the connection.
*
* Return value: Pointer to the uid string or NULL if not found
*/
const char *ssl_getuid(int sock)
{
int idx;
X509 *cert;
X509_NAME *subj;
ASN1_STRING *name;
if (!(cert = ssl_getcert(sock)))
return NULL;
/* Get the subject name */
if (!(subj = X509_get_subject_name(cert)))
return NULL;
/* Get the first UID */
idx = X509_NAME_get_index_by_NID(subj, NID_userId, -1);
if (idx == -1)
return NULL;
name = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(subj, idx));
/* Extract the contents, assuming null-terminated ASCII string */
return (const char *) egg_ASN1_string_data(name);
}
/* Compare the peer's host with their Common Name or dnsName found in
* it's certificate. Only the first domain component of cn is allowed to
* be a wildcard '*'. The non-wildcard characters are compared ignoring
* case.
*
* Return value: 1 if cn matches host, 0 otherwise.
*/
static int ssl_hostmatch(const char *cn, const char *host)
{
const char *p, *q, *r;
if ((r = strchr(cn + 1, '.')) && r[-1] == '*' && strchr(r, '.')) {
for (p = cn, q = host; *p != '*'; p++, q++)
if (toupper((const unsigned char)*p) != toupper((const unsigned char)*q))
return 0;
if (!(p = strchr(host, '.')) || strcasecmp(p, r))
return 0;
return 1;
}
/* First domain component is not a wildcard and they aren't allowed
elsewhere, so just compare the strings. */
return strcasecmp(cn, host) ? 0 : 1;
}
/* Confirm the peer identity, by checking if the certificate subject
* matches the peer's DNS name or IP address. Matching is performed in
* accordance with RFC 2818:
*
* If the certificate has a subjectAltName extension, all names of type
* IPAddress or dnsName present there, will be compared to data->host,
* depending on it's contents.
* In case there's no subjectAltName extension, commonName (CN) parts
* of the certificate subject field will be used instead of IPAddress
* and dnsName entries. For IP addresses, common names must contain IPs
* in presentation format (1.2.3.4 or 2001:DB8:15:dead::)
* Finally, if no subjectAltName or common names are present, the
* certificate is considered to not match the peer.
*
* The structure of X509 certificates and all fields referenced above
* are described in RFC 5280.
*
* The certificate must be pointed by cert and the peer's host must be
* placed in data->host. The format is a regular DNS name or an IP in
* presentation format (see above).
*
* Return value: 1 if the certificate matches the peer, 0 otherwise.
*/
static int ssl_verifycn(X509 *cert, ssl_appdata *data)
{
const char *cn;
int crit = 0, match = 0;
ASN1_OCTET_STRING *ip;
GENERAL_NAMES *altname; /* SubjectAltName ::= GeneralNames */
ip = a2i_IPADDRESS(data->host); /* check if it's an IP or a hostname */
if ((altname = X509_get_ext_d2i(cert, NID_subject_alt_name, &crit, NULL))) {
GENERAL_NAME *gn;
/* Loop through the general names in altname and pick these
of type ip address or dns name */
while (!match && (gn = sk_GENERAL_NAME_pop(altname))) {
/* if the peer's host is an IP, we're only interested in
matching against iPAddress general names, otherwise
we'll only look for dnsName's */
if (ip) {
if (gn->type == GEN_IPADD)
match = !ASN1_STRING_cmp(gn->d.ip, ip);
} else if (gn->type == GEN_DNS) {
/* IA5string holds ASCII data */
cn = (const char *) egg_ASN1_string_data(gn->d.ia5);
match = ssl_hostmatch(cn, data->host);
}
}
sk_GENERAL_NAME_free(altname);
} else { /* no subjectAltName, try to match against the subject CNs */
X509_NAME *subj; /* certificate subject */
/* the following is just for information */
switch (crit) {
case 0:
debug0("TLS: X509 subjectAltName cannot be decoded");
break;
case -1:
debug0("TLS: X509 has no subjectAltName extension");
break;
case -2:
debug0("TLS: X509 has multiple subjectAltName extensions");
}
/* no subject name either? A completely broken certificate :) */
if (!(subj = X509_get_subject_name(cert))) {
putlog(data->loglevel, "*", "TLS: peer certificate has no subject: %s",
data->host);
match = 0;
} else { /* we have a subject name, look at it */
int pos = -1;
ASN1_STRING *name;
/* Look for commonName attributes in the subject name */
pos = X509_NAME_get_index_by_NID(subj, NID_commonName, pos);
if (pos == -1) /* sorry */
putlog(data->loglevel, "*", "TLS: Peer has no common names and "
"no subjectAltName extension. Verification failed.");
/* Loop through all common names which may be present in the subject
name until we find a match. */
while (!match && pos != -1) {
name = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(subj, pos));
cn = (const char *) egg_ASN1_string_data(name);
if (ip)
match = a2i_IPADDRESS(cn) ? (ASN1_STRING_cmp(ip, a2i_IPADDRESS(cn)) ? 0 : 1) : 0;
else
match = ssl_hostmatch(cn, data->host);
pos = X509_NAME_get_index_by_NID(subj, NID_commonName, pos);
}
}
}
if (ip)
ASN1_OCTET_STRING_free(ip);
return match;
}
/* Extract a human readable version of a X509_NAME and put the result
* into a nmalloc'd buffer.
* The X509_NAME structure is used for example in certificate subject
* and issuer names.
*
* You need to nfree() the returned pointer.
*/
static char *ssl_printname(X509_NAME *name)
{
long len;
char *data, *buf;
BIO *bio = BIO_new(BIO_s_mem());
/* X509_NAME_oneline() is easier and shorter, but is deprecated and
the manual discourages it's usage, so let's not be lazy ;) */
if (X509_NAME_print_ex(bio, name, 0, XN_FLAG_ONELINE & ~XN_FLAG_SPC_EQ)) {
len = BIO_get_mem_data(bio, &data);
if (len > 0) {
buf = nmalloc(len + 1);
memcpy(buf, data, len); /* don't strlcpy() for it would read data[len] */
buf[len] = 0;
} else {
debug0("TLS: ssl_printname(): BIO_get_mem_data(): error");
buf = nmalloc(1);
*buf = 0;
}
} else {
debug0("TLS: ssl_printname(): X509_NAME_print_ex(): error");
buf = nmalloc(1);
*buf = 0;
}
BIO_free(bio);
return buf;
}
/* Print the time from a ASN1_UTCTIME object in standard format i.e.
* Nov 21 23:59:00 1996 GMT and store it in a nmalloc'd buffer.
* The ASN1_UTCTIME structure is what's used for example with
* certificate validity dates.
*
* You need to nfree() the returned pointer.
*/
static char *ssl_printtime(ASN1_UTCTIME *t)
{
long len;
char *data, *buf;
BIO *bio = BIO_new(BIO_s_mem());
ASN1_UTCTIME_print(bio, t);
len = BIO_get_mem_data(bio, &data);
if (len > 0) {
buf = nmalloc(len + 1);
memcpy(buf, data, len); /* don't strlcpy() for it would read data[len] */
buf[len] = 0;
} else {
debug0("TLS: ssl_printtime(): BIO_get_mem_data(): error");
buf = nmalloc(1);
*buf = 0;
}
BIO_free(bio);
return buf;
}
/* Print the value of an ASN1_INTEGER in hexadecimal format.
* A typical use for this is to display certificate serial numbers.
* As usual, we use a memory BIO.
*
* You need to nfree() the returned pointer.
*/
static char *ssl_printnum(ASN1_INTEGER *i)
{
long len;
char *data, *buf;
BIO *bio = BIO_new(BIO_s_mem());
i2a_ASN1_INTEGER(bio, i);
len = BIO_get_mem_data(bio, &data);
if (len > 0) {
buf = nmalloc(len + 1);
memcpy(buf, data, len); /* don't strlcpy() for it would read data[len] */
buf[len] = 0;
} else {
debug0("TLS: ssl_printnum(): BIO_get_mem_data(): error");
buf = nmalloc(1);
*buf = 0;
}
BIO_free(bio);
return buf;
}
/* Show the user all relevant information about a certificate: subject,
* issuer, validity dates and fingerprints.
*/
static void ssl_showcert(X509 *cert, const int loglev)
{
char *buf, *from, *to;
X509_NAME *name;
unsigned int len;
unsigned char md[EVP_MAX_MD_SIZE];
/* Subject and issuer names */
if ((name = X509_get_subject_name(cert))) {
buf = ssl_printname(name);
putlog(loglev, "*", "TLS: certificate subject: %s", buf);
nfree(buf);
} else
putlog(loglev, "*", "TLS: cannot get subject name from certificate!");
if ((name = X509_get_issuer_name(cert))) {
buf = ssl_printname(name);
putlog(loglev, "*", "TLS: certificate issuer: %s", buf);
nfree(buf);
} else
putlog(loglev, "*", "TLS: cannot get issuer name from certificate!");
/* Fingerprints */
if (X509_digest(cert, EVP_sha1(), md, &len)) {
buf = OPENSSL_buf2hexstr(md, len);
putlog(loglev, "*", "TLS: certificate SHA1 Fingerprint: %s", buf);
OPENSSL_free(buf);
}
if (X509_digest(cert, EVP_sha256(), md, &len)) {
buf = OPENSSL_buf2hexstr(md, len);
putlog(loglev, "*", "TLS: certificate SHA-256 Fingerprint: %s", buf);
OPENSSL_free(buf);
}
/* Validity time */
from = ssl_printtime(X509_get_notBefore(cert));
to = ssl_printtime(X509_get_notAfter(cert));
putlog(loglev, "*", "TLS: certificate valid from %s to %s", from, to);
nfree(from);
nfree(to);
}
/* Certificate validation callback
*
* Check if the certificate given is valid with respect to the
* ssl-verify config variable. This makes it possible to allow
* self-signed certificates and is also a convenient place to
* extract a certificate summary.
*
* Return value: 1 - validation passed, 0 - invalid cert
*/
int ssl_verify(int ok, X509_STORE_CTX *ctx)
{
SSL *ssl;
X509 *cert;
ssl_appdata *data;
int err, depth;
/* get cert, callbacks, error codes, etc. */
depth = X509_STORE_CTX_get_error_depth(ctx);
cert = X509_STORE_CTX_get_current_cert(ctx);
ssl = X509_STORE_CTX_get_ex_data(ctx,
SSL_get_ex_data_X509_STORE_CTX_idx());
data = (ssl_appdata *) SSL_get_app_data(ssl);
err = X509_STORE_CTX_get_error(ctx);
/* OpenSSL won't explicitly generate this error; instead it will
* report missing certificates. Refer to SSL_CTX_set_verify(3)
* manual for details
*/
if (depth > tls_maxdepth) {
ok = 0;
err = X509_V_ERR_CERT_CHAIN_TOO_LONG;
/* depth 0 is actually the peer certificate. We do all custom
* verification here and leave the rest of the certificate chain
* to OpenSSL's built in procedures.
*/
} else if (!depth) {
/* OpenSSL doesn't perform subject name verification. We need to do
* it ourselves. We check here for validity even if it's not requested
* in order to be able to warn the user.
*/
if (!(data->flags & TLS_DEPTH0) && (data->verify & TLS_VERIFYCN) &&
!ssl_verifycn(cert, data)) {
putlog(data->loglevel, "*", "TLS: certificate validation failed. "
"Certificate subject does not match peer.");
return 0;
}
data->flags |= TLS_DEPTH0;
/* Allow exceptions for certain common verification errors, if the
* caller requested so. A lot of servers provide completely invalid
* certificates useless for any authentication.
*/
if (!ok || data->verify)
if (((err == X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT) &&
!(data->verify & TLS_VERIFYISSUER)) ||
((err == X509_V_ERR_CERT_REVOKED) &&
!(data->verify & TLS_VERIFYREV)) ||
((err == X509_V_ERR_CERT_NOT_YET_VALID) &&
!(data->verify & TLS_VERIFYFROM)) ||
((err == X509_V_ERR_CERT_HAS_EXPIRED) &&
!(data->verify & TLS_VERIFYTO))) {
debug1("TLS: peer certificate warning: %s",
X509_verify_cert_error_string(err));
ok = 1;
}
}
if (ok || !data->verify)
return 1;
putlog(data->loglevel, "*",
"TLS: certificate validation failed at depth %d: %s",
depth, X509_verify_cert_error_string(err));
return 0;
}
/* SSL info callback, this is used to trace engine state changes
* and to check when the handshake is finished, so we can display
* some cipher and session information and process callbacks.
*/
void ssl_info(SSL *ssl, int where, int ret)
{
int sock;
X509 *cert;
char buf[256];
ssl_appdata *data;
#if OPENSSL_VERSION_NUMBER >= 0x009080d1L /* 0.9.8m-beta1 */
const
#endif
SSL_CIPHER *cipher;
int secret, processed;
if (!(data = (ssl_appdata *) SSL_get_app_data(ssl)))
return;
/* We're doing non-blocking IO, so we check here if the handshake has
finished */
if (where & SSL_CB_HANDSHAKE_DONE) {
/* Callback for completed handshake. Cheaper and more convenient than
using H_tls */
sock = SSL_get_fd(ssl);
if (data->cb)
data->cb(sock);
/* Call TLS binds. We allow scripts to take over or disable displaying of
certificate information. */
if (check_tcl_tls(sock))
return;
putlog(data->loglevel, "*", "TLS: handshake successful. Secure connection "
"established.");
if ((cert = SSL_get_peer_certificate(ssl))) {
ssl_showcert(cert, data->loglevel);
X509_free(cert);
}
else
putlog(data->loglevel, "*", "TLS: peer did not present a certificate");
/* Display cipher information */
cipher = SSL_get_current_cipher(ssl);
processed = SSL_CIPHER_get_bits(cipher, &secret);
putlog(data->loglevel, "*", "TLS: cipher used: %s %s; %d bits (%d secret)",
SSL_CIPHER_get_name(cipher), SSL_CIPHER_get_version(cipher),
processed, secret);
/* secret are the actually secret bits. If processed and secret differ,
the rest of the bits are fixed, i.e. for limited export ciphers */
/* More verbose information, for debugging only */
SSL_CIPHER_description(cipher, buf, sizeof buf);
debug1("TLS: cipher details: %s", buf);
} else if (where & SSL_CB_ALERT) {
if (strcmp(SSL_alert_type_string(ret), "W") ||
strcmp(SSL_alert_desc_string(ret), "CN")) {
putlog(data->loglevel, "*", "TLS: alert during %s: %s (%s).",
(where & SSL_CB_READ) ? "read" : "write",
SSL_alert_type_string_long(ret),
SSL_alert_desc_string_long(ret));
} else {
/* Ignore close notify warnings */
debug1("Received close notify warning during %s",
(where & SSL_CB_READ) ? "read" : "write");
}
} else if (where & SSL_CB_EXIT) {
/* SSL_CB_EXIT may point to soft error for non-blocking! */
if (ret == 0) {
/* According to manpage, only 0 indicates a real error */
putlog(data->loglevel, "*", "TLS: failed in: %s.",
SSL_state_string_long(ssl));
} else if (ret < 0) {
int err = SSL_get_error(ssl, ret);
/* However we still check <0 as man example does so too */
if (err & (SSL_ERROR_WANT_READ | SSL_ERROR_WANT_WRITE)) {
/* Errors to be ignored for non-blocking */
debug1("TLS: awaiting more %s", (err & SSL_ERROR_WANT_READ) ? "reads" : "writes");
} else {
putlog(data->loglevel, "*", "TLS: error in: %s.",
SSL_state_string_long(ssl));
}
}
} else {
/* Display the state of the engine for debugging purposes */
debug1("TLS: state change: %s", SSL_state_string_long(ssl));
}
}
/* Switch a socket to SSL communication
*
* Creates a SSL data structure for the connection;
* Sets up callbacks and initiates a SSL handshake with the peer;
* Reports error conditions and performs cleanup upon failure.
*
* flags: ssl flags, i.e connect or listen
* verify: peer certificate verification flags
* loglevel: is the level to output information about the connection
* and certificates.
* host: contains the dns name or ip address of the peer. Used for
* verification.
* cb: optional callback, this function will be called after the
* handshake completes.
*
* Return value: 0 on success, !=0 on failure.
*/
int ssl_handshake(int sock, int flags, int verify, int loglevel, char *host,
IntFunc cb)
{
int i, err, ret;
ssl_appdata *data;
struct threaddata *td = threaddata();
debug0("TLS: attempting SSL negotiation...");
if (!ssl_ctx && ssl_init()) {
debug0("TLS: Failed. OpenSSL not initialized properly.");
return -1;
}
if ((flags & TLS_LISTEN) && !ssl_files_loaded) {
putlog(LOG_MISC, "*", "TLS: Failed. Certificate/Key not loaded, cannot support SSL/TLS for client (see doc/TLS).");
return -4;
}
/* find the socket in the list */
i = findsock(sock);
if (i == -1) {
debug0("TLS: socket not in socklist");
return -2;
}
if (td->socklist[i].ssl) {
debug0("TLS: handshake not required - SSL session already established");
return 0;
}
td->socklist[i].ssl = SSL_new(ssl_ctx);
if (!td->socklist[i].ssl ||
!SSL_set_fd(td->socklist[i].ssl, td->socklist[i].sock)) {
debug1("TLS: cannot initiate SSL session - %s",
ERR_error_string(ERR_get_error(), 0));
return -3;
}
/* Prepare a ssl appdata struct for the verify callback */
data = nmalloc(sizeof(ssl_appdata));
egg_bzero(data, sizeof(ssl_appdata));
data->flags = flags & (TLS_LISTEN | TLS_CONNECT);
data->verify = verify;
/* Invert these flags as their corresponding configuration values express
* exceptions
*/
if (data->verify)
data->verify ^= (TLS_VERIFYISSUER | TLS_VERIFYCN | TLS_VERIFYFROM |
TLS_VERIFYTO | TLS_VERIFYREV);
data->loglevel = loglevel;
data->cb = cb;
strlcpy(data->host, host ? host : "", sizeof(data->host));
SSL_set_app_data(td->socklist[i].ssl, data);
SSL_set_info_callback(td->socklist[i].ssl, (void *) ssl_info);
/* We set this +1 to be able to report extra long chains properly.
* Otherwise, OpenSSL will break the verification reporting about
* missing certificates instead. The rest of the fix is in
* ssl_verify()
*/
SSL_set_verify_depth(td->socklist[i].ssl, tls_maxdepth + 1);
SSL_set_mode(td->socklist[i].ssl, SSL_MODE_ENABLE_PARTIAL_WRITE |
SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
if (data->flags & TLS_CONNECT) {
struct timespec req = { 0, 1000000L };
SSL_set_verify(td->socklist[i].ssl, SSL_VERIFY_PEER, ssl_verify);
/* Introduce 1ms lag so an unpatched hub has time to setup the ssl handshake */
nanosleep(&req, NULL);
ret = SSL_connect(td->socklist[i].ssl);
if (!ret)
debug0("TLS: connect handshake failed.");
} else {
if (data->verify & TLS_VERIFYPEER)
SSL_set_verify(td->socklist[i].ssl, SSL_VERIFY_PEER |
SSL_VERIFY_FAIL_IF_NO_PEER_CERT, ssl_verify);
else
SSL_set_verify(td->socklist[i].ssl, SSL_VERIFY_PEER, ssl_verify);
ret = SSL_accept(td->socklist[i].ssl);
if (!ret)
debug0("TLS: accept handshake failed");
}
err = SSL_get_error(td->socklist[i].ssl, ret);
/* Normal condition for async I/O, similar to EAGAIN */
if (ret > 0 || err == SSL_ERROR_WANT_READ || err == SSL_ERROR_WANT_WRITE) {
debug0("TLS: handshake in progress");
return 0;
}
if ((err = ERR_peek_error())) {
putlog(data->loglevel, "*",
"TLS: handshake failed due to the following error: %s",
ERR_reason_error_string(err));
debug0("TLS: handshake failed due to the following errors: ");
while ((err = ERR_get_error()))
debug1("TLS: %s", ERR_error_string(err, NULL));
}
/* Attempt failed, cleanup and abort */
SSL_shutdown(td->socklist[i].ssl);
SSL_free(td->socklist[i].ssl);
td->socklist[i].ssl = NULL;
nfree(data);
return -4;
}
/* Tcl functions */
/* Is the connection secure? */
static int tcl_istls STDVAR
{
int j;
BADARGS(2, 2, " idx");
j = findidx(atoi(argv[1]));
if (j < 0) {
Tcl_AppendResult(irp, "invalid idx", NULL);
return TCL_ERROR;
}
if (dcc[j].ssl)
Tcl_AppendResult(irp, "1", NULL);
else
Tcl_AppendResult(irp, "0", NULL);
return TCL_OK;
}
/* Perform a SSL handshake over an existing plain text
* connection.
*/
static int tcl_starttls STDVAR
{
int j;
struct threaddata *td = threaddata();
BADARGS(2, 2, " idx");
j = findidx(atoi(argv[1]));
if (j < 0 || (dcc[j].type != &DCC_SCRIPT)) {
Tcl_AppendResult(irp, "invalid idx", NULL);
return TCL_ERROR;
}
if (dcc[j].ssl) {
Tcl_AppendResult(irp, "already started", NULL);
return TCL_ERROR;
}
/* Determine if we're playing a client or a server */
j = findsock(dcc[j].sock);
if (ssl_handshake(dcc[j].sock, (td->socklist[j].flags & SOCK_CONNECT) ?
TLS_CONNECT : TLS_LISTEN, tls_vfydcc, LOG_MISC, NULL, NULL))
Tcl_AppendResult(irp, "0", NULL);
else
Tcl_AppendResult(irp, "1", NULL);
return TCL_OK;
}
/* Get all relevant information about an established ssl connection.
* This includes certificate subject and issuer, serial number,
* expiry date, protocol version and cipher information.
* All data is presented as a flat list consisting of name-value pairs.
*/
static int tcl_tlsstatus STDVAR
{
char *p;
int i, j;
X509 *cert;
const SSL_CIPHER *cipher;
struct threaddata *td = threaddata();
Tcl_DString ds;
BADARGS(2, 2, " idx");
/* Allow it to be used for any connection, not just scripted
* ones. This makes it possible for a script to display the
* server certificate.
*/
i = findanyidx(atoi(argv[1]));
if (i < 0) {
Tcl_AppendResult(irp, "invalid idx", NULL);
return TCL_ERROR;
}
j = findsock(dcc[i].sock);
if (!j || !dcc[i].ssl || !td->socklist[j].ssl) {
Tcl_AppendResult(irp, "not a TLS connection", NULL);
return TCL_ERROR;
}
Tcl_DStringInit(&ds);
/* Try to get a cert, clients aren't required to send a
* certificate, so this is optional
*/
cert = SSL_get_peer_certificate(td->socklist[j].ssl);
/* The following information is certificate dependent */
if (cert) {
p = ssl_printname(X509_get_subject_name(cert));
Tcl_DStringAppendElement(&ds, "subject");
Tcl_DStringAppendElement(&ds, p);
nfree(p);
p = ssl_printname(X509_get_issuer_name(cert));
Tcl_DStringAppendElement(&ds, "issuer");
Tcl_DStringAppendElement(&ds, p);
nfree(p);
p = ssl_printtime(X509_get_notBefore(cert));
Tcl_DStringAppendElement(&ds, "notBefore");
Tcl_DStringAppendElement(&ds, p);
nfree(p);
p = ssl_printtime(X509_get_notAfter(cert));
Tcl_DStringAppendElement(&ds, "notAfter");
Tcl_DStringAppendElement(&ds, p);
nfree(p);
p = ssl_printnum(X509_get_serialNumber(cert));
Tcl_DStringAppendElement(&ds, "serial");
Tcl_DStringAppendElement(&ds, p);
nfree(p);
}
/* We should always have a cipher, but who knows? */
cipher = SSL_get_current_cipher(td->socklist[j].ssl);
if (cipher) { /* don't bother if there's none */
Tcl_DStringAppendElement(&ds, "protocol");
Tcl_DStringAppendElement(&ds, SSL_CIPHER_get_version(cipher));
Tcl_DStringAppendElement(&ds, "cipher");
Tcl_DStringAppendElement(&ds, SSL_CIPHER_get_name(cipher));
}
/* Done, get a Tcl list from this and return it to the caller */
Tcl_AppendResult(irp, Tcl_DStringValue(&ds), NULL);
Tcl_DStringFree(&ds);
return TCL_OK;
}
/* These will be added by tcl.c which is the established practice */
tcl_cmds tcltls_cmds[] = {
{"istls", tcl_istls},
{"starttls", tcl_starttls},
{"tlsstatus", tcl_tlsstatus},
{NULL, NULL}
};
#endif /* TLS */