-/*
- * $Id$
- *
- * Provides HTTPS, when the OpenSSL library is available.
- */
-
+// Copyright (c) 1996-2022 by the citadel.org team
+//
+// This program is open source software. You can redistribute it and/or
+// modify it under the terms of the GNU General Public License, version 3.
+//
+// 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.
+
+#include "sysdep.h"
#ifdef HAVE_OPENSSL
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <pthread.h>
-
-#include <sys/time.h>
#include "webcit.h"
-#include "webserver.h"
-#define CTDL_CRYPTO_DIR WEBCITDIR "/keys"
-#define CTDL_KEY_PATH CTDL_CRYPTO_DIR "/citadel.key"
-#define CTDL_CSR_PATH CTDL_CRYPTO_DIR "/citadel.csr"
-#define CTDL_CER_PATH CTDL_CRYPTO_DIR "/citadel.cer"
-#define SIGN_DAYS 365
-/* Shared Diffie-Hellman parameters */
-#define DH_P "1A74527AEE4EE2568E85D4FB2E65E18C9394B9C80C42507D7A6A0DBE9A9A54B05A9A96800C34C7AA5297095B69C88901EEFD127F969DCA26A54C0E0B5C5473EBAEB00957D2633ECAE3835775425DE66C0DE6D024DBB17445E06E6B0C78415E589B8814F08531D02FD43778451E7685541079CFFB79EF0D26EFEEBBB69D1E80383"
-#define DH_G "2"
-#define DH_L 1024
+SSL_CTX *ssl_ctx; // Global SSL context
+char key_file[PATH_MAX] = "";
+char cert_file[PATH_MAX] = "";
+char *ssl_cipher_list = DEFAULT_SSL_CIPHER_LIST;
-SSL_CTX *ssl_ctx; /* SSL context */
-pthread_mutex_t **SSLCritters; /* Things needing locking */
+pthread_key_t ThreadSSL; // Per-thread SSL context
-pthread_key_t ThreadSSL; /* Per-thread SSL context */
-static unsigned long id_callback(void)
-{
- return (unsigned long) pthread_self();
-}
+// Set the private key and certificate chain for the global SSL Context.
+// This is called during initialization, and can be called again later if the certificate changes.
+void bind_to_key_and_certificate(void) {
+ SSL_CTX *old_ctx, *new_ctx;
-void init_ssl(void)
-{
- SSL_METHOD *ssl_method;
- DH *dh;
- RSA *rsa=NULL;
- X509_REQ *req = NULL;
- X509 *cer = NULL;
- EVP_PKEY *pk = NULL;
- EVP_PKEY *req_pkey = NULL;
- X509_NAME *name = NULL;
- FILE *fp;
- char buf[SIZ];
-
- if (!access("/var/run/egd-pool", F_OK))
- RAND_egd("/var/run/egd-pool");
-
- if (!RAND_status()) {
- lprintf(3,
- "PRNG not adequately seeded, won't do SSL/TLS\n");
- return;
+ if (IsEmptyStr(key_file)) {
+ snprintf(key_file, sizeof key_file, "%s/keys/citadel.key", ctdl_dir);
}
- SSLCritters =
- malloc(CRYPTO_num_locks() * sizeof(pthread_mutex_t *));
- if (!SSLCritters) {
- lprintf(1, "citserver: can't allocate memory!!\n");
- /* Nothing's been initialized, just die */
- exit(1);
- } else {
- int a;
-
- for (a = 0; a < CRYPTO_num_locks(); a++) {
- SSLCritters[a] = malloc(sizeof(pthread_mutex_t));
- if (!SSLCritters[a]) {
- lprintf(1,
- "citserver: can't allocate memory!!\n");
- /* Nothing's been initialized, just die */
- exit(1);
- }
- pthread_mutex_init(SSLCritters[a], NULL);
- }
+ if (IsEmptyStr(cert_file)) {
+ snprintf(cert_file, sizeof key_file, "%s/keys/citadel.cer", ctdl_dir);
}
- /*
- * Initialize SSL transport layer
- */
- SSL_library_init();
- /* OpenSSL_add_all_algorithms(); */
- SSL_load_error_strings();
- ssl_method = SSLv2_server_method();
- if (!(ssl_ctx = SSL_CTX_new(ssl_method))) {
- lprintf(3, "SSL_CTX_new failed: %s\n",
- ERR_reason_error_string(ERR_get_error()));
+ if (!(new_ctx = SSL_CTX_new(SSLv23_server_method()))) {
+ syslog(LOG_WARNING, "SSL_CTX_new failed: %s", ERR_reason_error_string(ERR_get_error()));
return;
}
- CRYPTO_set_locking_callback(ssl_lock);
- CRYPTO_set_id_callback(id_callback);
-
- /* Load DH parameters into the context */
- dh = DH_new();
- if (!dh) {
- lprintf(3, "init_ssl() can't allocate a DH object: %s\n",
- ERR_reason_error_string(ERR_get_error()));
- SSL_CTX_free(ssl_ctx);
- ssl_ctx = NULL;
+ syslog(LOG_INFO, "Requesting cipher list: %s", ssl_cipher_list);
+ if (!(SSL_CTX_set_cipher_list(new_ctx, ssl_cipher_list))) {
+ syslog(LOG_WARNING, "SSL_CTX_set_cipher_list failed: %s", ERR_reason_error_string(ERR_get_error()));
return;
}
- if (!(BN_hex2bn(&(dh->p), DH_P))) {
- lprintf(3, "init_ssl() can't assign DH_P: %s\n",
- ERR_reason_error_string(ERR_get_error()));
- SSL_CTX_free(ssl_ctx);
- ssl_ctx = NULL;
- return;
- }
- if (!(BN_hex2bn(&(dh->g), DH_G))) {
- lprintf(3, "init_ssl() can't assign DH_G: %s\n",
- ERR_reason_error_string(ERR_get_error()));
- SSL_CTX_free(ssl_ctx);
- ssl_ctx = NULL;
- return;
- }
- dh->length = DH_L;
- SSL_CTX_set_tmp_dh(ssl_ctx, dh);
- DH_free(dh);
-
- /* Get our certificates in order.
- * First, create the key/cert directory if it's not there already...
- */
- mkdir(CTDL_CRYPTO_DIR, 0700);
-
- /*
- * Before attempting to generate keys/certificates, first try
- * link to them from the Citadel server if it's on the same host.
- * We ignore any error return because it either meant that there
- * was nothing in Citadel to link from (in which case we just
- * generate new files) or the target files already exist (which
- * is not fatal either).
- */
- if (!strcasecmp(ctdlhost, "uds")) {
- sprintf(buf, "%s/keys/citadel.key", ctdlport);
- symlink(buf, CTDL_KEY_PATH);
- sprintf(buf, "%s/keys/citadel.csr", ctdlport);
- symlink(buf, CTDL_CSR_PATH);
- sprintf(buf, "%s/keys/citadel.cer", ctdlport);
- symlink(buf, CTDL_CER_PATH);
- }
- /*
- * If we still don't have a private key, generate one.
- */
- if (access(CTDL_KEY_PATH, R_OK) != 0) {
- lprintf(5, "Generating RSA key pair.\n");
- rsa = RSA_generate_key(1024, /* modulus size */
- 65537, /* exponent */
- NULL, /* no callback */
- NULL); /* no callback */
- if (rsa == NULL) {
- lprintf(3, "Key generation failed: %s\n",
- ERR_reason_error_string(ERR_get_error()));
- }
- if (rsa != NULL) {
- fp = fopen(CTDL_KEY_PATH, "w");
- if (fp != NULL) {
- chmod(CTDL_KEY_PATH, 0600);
- if (PEM_write_RSAPrivateKey(fp, /* the file */
- rsa, /* the key */
- NULL, /* no enc */
- NULL, /* no passphr */
- 0, /* no passphr */
- NULL, /* no callbk */
- NULL /* no callbk */
- ) != 1) {
- lprintf(3, "Cannot write key: %s\n",
- ERR_reason_error_string(ERR_get_error()));
- unlink(CTDL_KEY_PATH);
- }
- fclose(fp);
- }
- RSA_free(rsa);
- }
- }
+ syslog(LOG_DEBUG, "crypto: [re]installing key \"%s\" and certificate \"%s\"", key_file, cert_file);
- /*
- * Generate a CSR if we don't have one.
- */
- if (access(CTDL_CSR_PATH, R_OK) != 0) {
- lprintf(5, "Generating a certificate signing request.\n");
-
- /*
- * Read our key from the file. No, we don't just keep this
- * in memory from the above key-generation function, because
- * there is the possibility that the key was already on disk
- * and we didn't just generate it now.
- */
- fp = fopen(CTDL_KEY_PATH, "r");
- if (fp) {
- rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
- fclose(fp);
- }
-
- if (rsa) {
-
- /* Create a public key from the private key */
- if (pk=EVP_PKEY_new(), pk != NULL) {
- EVP_PKEY_assign_RSA(pk, rsa);
- if (req = X509_REQ_new(), req != NULL) {
-
- /* Set the public key */
- X509_REQ_set_pubkey(req, pk);
- X509_REQ_set_version(req, 0L);
-
- name = X509_REQ_get_subject_name(req);
-
- /* Tell it who we are */
-
- /*
- X509_NAME_add_entry_by_txt(name, "C",
- MBSTRING_ASC, "US", -1, -1, 0);
-
- X509_NAME_add_entry_by_txt(name, "ST",
- MBSTRING_ASC, "New York", -1, -1, 0);
-
- X509_NAME_add_entry_by_txt(name, "L",
- MBSTRING_ASC, "Mount Kisco", -1, -1, 0);
- */
-
- X509_NAME_add_entry_by_txt(name, "O",
- MBSTRING_ASC, "FIXME.FIXME.org", -1, -1, 0);
-
- X509_NAME_add_entry_by_txt(name, "OU",
- MBSTRING_ASC, "Citadel server", -1, -1, 0);
-
- X509_NAME_add_entry_by_txt(name, "CN",
- MBSTRING_ASC, "FIXME.FIXME.org", -1, -1, 0);
-
- X509_REQ_set_subject_name(req, name);
-
- /* Sign the CSR */
- if (!X509_REQ_sign(req, pk, EVP_md5())) {
- lprintf(3, "X509_REQ_sign(): error\n");
- }
- else {
- /* Write it to disk. */
- fp = fopen(CTDL_CSR_PATH, "w");
- if (fp != NULL) {
- chmod(CTDL_CSR_PATH, 0600);
- PEM_write_X509_REQ(fp, req);
- fclose(fp);
- }
- }
-
- X509_REQ_free(req);
- }
- }
-
- RSA_free(rsa);
- }
+ SSL_CTX_use_certificate_chain_file(new_ctx, cert_file);
+ SSL_CTX_use_PrivateKey_file(new_ctx, key_file, SSL_FILETYPE_PEM);
- else {
- lprintf(3, "Unable to read private key.\n");
- }
+ if ( !SSL_CTX_check_private_key(new_ctx) ) {
+ syslog(LOG_WARNING, "crypto: cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
}
+ old_ctx = ssl_ctx;
+ ssl_ctx = new_ctx;
+ sleep(1);
+ SSL_CTX_free(old_ctx);
+}
- /*
- * Generate a self-signed certificate if we don't have one.
- */
- if (access(CTDL_CER_PATH, R_OK) != 0) {
- lprintf(5, "Generating a self-signed certificate.\n");
+// initialize ssl engine, load certs and initialize openssl internals
+void init_ssl(void) {
- /* Same deal as before: always read the key from disk because
- * it may or may not have just been generated.
- */
- fp = fopen(CTDL_KEY_PATH, "r");
- if (fp) {
- rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
- fclose(fp);
- }
+ // Initialize the OpenSSL library
+ SSL_load_error_strings();
+ ERR_load_crypto_strings();
+ OpenSSL_add_all_algorithms();
+ SSL_library_init();
- /* This also holds true for the CSR. */
- req = NULL;
- cer = NULL;
- pk = NULL;
- if (rsa) {
- if (pk=EVP_PKEY_new(), pk != NULL) {
- EVP_PKEY_assign_RSA(pk, rsa);
- }
+ // Now try to bind to the key and certificate.
+ bind_to_key_and_certificate();
+}
- fp = fopen(CTDL_CSR_PATH, "r");
- if (fp) {
- req = PEM_read_X509_REQ(fp, NULL, NULL, NULL);
- fclose(fp);
- }
- if (req) {
- if (cer = X509_new(), cer != NULL) {
-
- ASN1_INTEGER_set(X509_get_serialNumber(cer), 0);
- X509_set_issuer_name(cer, req->req_info->subject);
- X509_set_subject_name(cer, req->req_info->subject);
- X509_gmtime_adj(X509_get_notBefore(cer), 0);
- X509_gmtime_adj(X509_get_notAfter(cer),(long)60*60*24*SIGN_DAYS);
-
- req_pkey = X509_REQ_get_pubkey(req);
- X509_set_pubkey(cer, req_pkey);
- EVP_PKEY_free(req_pkey);
-
- /* Sign the cert */
- if (!X509_sign(cer, pk, EVP_md5())) {
- lprintf(3, "X509_sign(): error\n");
- }
- else {
- /* Write it to disk. */
- fp = fopen(CTDL_CER_PATH, "w");
- if (fp != NULL) {
- chmod(CTDL_CER_PATH, 0600);
- PEM_write_X509(fp, cer);
- fclose(fp);
- }
- }
- X509_free(cer);
- }
- }
+// Check the modification time of the key and certificate -- reload if either one changed
+void update_key_and_cert_if_needed(void) {
+ static time_t previous_mtime = 0;
+ struct stat keystat;
+ struct stat certstat;
- RSA_free(rsa);
- }
+ if (stat(key_file, &keystat) != 0) {
+ syslog(LOG_ERR, "%s: %s", key_file, strerror(errno));
+ return;
+ }
+ if (stat(cert_file, &certstat) != 0) {
+ syslog(LOG_ERR, "%s: %s", cert_file, strerror(errno));
+ return;
}
-
- /*
- * Now try to bind to the key and certificate.
- * Note that we use SSL_CTX_use_certificate_chain_file() which allows
- * the certificate file to contain intermediate certificates.
- */
- SSL_CTX_use_certificate_chain_file(ssl_ctx, CTDL_CER_PATH);
- SSL_CTX_use_PrivateKey_file(ssl_ctx, CTDL_KEY_PATH, SSL_FILETYPE_PEM);
- if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
- lprintf(3, "Cannot install certificate: %s\n",
- ERR_reason_error_string(ERR_get_error()));
+ if ((keystat.st_mtime + certstat.st_mtime) != previous_mtime) {
+ bind_to_key_and_certificate();
+ previous_mtime = keystat.st_mtime + certstat.st_mtime;
}
-
}
-/*
- * starttls() starts SSL/TLS encryption for the current session.
- */
+// starts SSL/TLS encryption for the current session.
int starttls(int sock) {
- int retval, bits, alg_bits;
SSL *newssl;
+ int retval, bits, alg_bits;
+ // Check the modification time of the key and certificate -- reload if they changed
+ update_key_and_cert_if_needed();
+
+ // SSL is a thread-specific thing, I think.
pthread_setspecific(ThreadSSL, NULL);
if (!ssl_ctx) {
return(1);
}
if (!(newssl = SSL_new(ssl_ctx))) {
- lprintf(3, "SSL_new failed: %s\n",
- ERR_reason_error_string(ERR_get_error()));
+ syslog(LOG_WARNING, "SSL_new failed: %s", ERR_reason_error_string(ERR_get_error()));
return(2);
}
if (!(SSL_set_fd(newssl, sock))) {
- lprintf(3, "SSL_set_fd failed: %s\n",
- ERR_reason_error_string(ERR_get_error()));
+ syslog(LOG_WARNING, "SSL_set_fd failed: %s", ERR_reason_error_string(ERR_get_error()));
SSL_free(newssl);
return(3);
}
retval = SSL_accept(newssl);
if (retval < 1) {
- /*
- * Can't notify the client of an error here; they will
- * discover the problem at the SSL layer and should
- * revert to unencrypted communications.
- */
+ // Can't notify the client of an error here; they will
+ // discover the problem at the SSL layer and should
+ // revert to unencrypted communications.
long errval;
+ const char *ssl_error_reason = NULL;
errval = SSL_get_error(newssl, retval);
- lprintf(3, "SSL_accept failed: %s\n",
- ERR_reason_error_string(ERR_get_error()));
- SSL_free(newssl);
- newssl = NULL;
- return(4);
+ ssl_error_reason = ERR_reason_error_string(ERR_get_error());
+ if (ssl_error_reason == NULL) {
+ syslog(LOG_WARNING, "first SSL_accept failed: errval=%ld, retval=%d %s", errval, retval, strerror(errval));
+ }
+ else {
+ syslog(LOG_WARNING, "first SSL_accept failed: %s", ssl_error_reason);
+ }
+ }
+ else {
+ syslog(LOG_INFO, "SSL_accept success");
}
- BIO_set_close(newssl->rbio, BIO_NOCLOSE);
- bits =
- SSL_CIPHER_get_bits(SSL_get_current_cipher(newssl),
- &alg_bits);
- lprintf(5, "SSL/TLS using %s on %s (%d of %d bits)\n",
+ BIO_set_close(SSL_get_rbio(newssl), BIO_NOCLOSE);
+ bits = SSL_CIPHER_get_bits(SSL_get_current_cipher(newssl), &alg_bits);
+ syslog(LOG_INFO, "SSL/TLS using %s on %s (%d of %d bits)",
SSL_CIPHER_get_name(SSL_get_current_cipher(newssl)),
SSL_CIPHER_get_version(SSL_get_current_cipher(newssl)),
bits, alg_bits);
pthread_setspecific(ThreadSSL, newssl);
+ syslog(LOG_INFO, "SSL started");
return(0);
}
+// shuts down the TLS connection
+//
+// WARNING: This may make your session vulnerable to a known plaintext
+// attack in the current implmentation.
+void endtls(void) {
-/*
- * endtls() shuts down the TLS connection
- *
- * WARNING: This may make your session vulnerable to a known plaintext
- * attack in the current implmentation.
- */
-void endtls(void)
-{
- lprintf(5, "Ending SSL/TLS\n");
+ if (THREADSSL == NULL) {
+ return;
+ }
+
+ syslog(LOG_INFO, "Ending SSL/TLS");
SSL_shutdown(THREADSSL);
+ SSL_get_SSL_CTX(THREADSSL);
SSL_free(THREADSSL);
pthread_setspecific(ThreadSSL, NULL);
}
-/*
- * ssl_lock() callback for OpenSSL mutex locks
- */
-void ssl_lock(int mode, int n, const char *file, int line)
-{
- if (mode & CRYPTO_LOCK)
- pthread_mutex_lock(SSLCritters[n]);
- else
- pthread_mutex_unlock(SSLCritters[n]);
-}
-
-/*
- * client_write_ssl() Send binary data to the client encrypted.
- */
-void client_write_ssl(char *buf, int nbytes)
-{
+// Send binary data to the client encrypted.
+int client_write_ssl(const StrBuf *Buf) {
+ const char *buf;
int retval;
int nremain;
+ long nbytes;
char junk[1];
- nremain = nbytes;
+ if (THREADSSL == NULL) return -1;
+
+ nbytes = nremain = StrLength(Buf);
+ buf = ChrPtr(Buf);
while (nremain > 0) {
if (SSL_want_write(THREADSSL)) {
if ((SSL_read(THREADSSL, junk, 0)) < 1) {
- lprintf(9, "SSL_read in client_write: %s\n", ERR_reason_error_string(ERR_get_error()));
+ syslog(LOG_WARNING, "SSL_read in client_write: %s", ERR_reason_error_string(ERR_get_error()));
}
}
- retval =
- SSL_write(THREADSSL, &buf[nbytes - nremain], nremain);
+ retval = SSL_write(THREADSSL, &buf[nbytes - nremain], nremain);
if (retval < 1) {
long errval;
errval = SSL_get_error(THREADSSL, retval);
- if (errval == SSL_ERROR_WANT_READ ||
- errval == SSL_ERROR_WANT_WRITE) {
- sleep(1);
+ if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
+ sleeeeeeeeeep(1);
continue;
}
- lprintf(9, "SSL_write got error %ld, ret %d\n", errval, retval);
- if (retval == -1)
- lprintf(9, "errno is %d\n", errno);
+ syslog(LOG_WARNING, "SSL_write: %s", ERR_reason_error_string(ERR_get_error()));
+ if (retval == -1) {
+ syslog(LOG_WARNING, "errno is %d\n", errno);
+ }
endtls();
- return;
+ return -1;
}
nremain -= retval;
}
+ return 0;
}
-/*
- * client_read_ssl() - read data from the encrypted layer.
- */
-int client_read_ssl(char *buf, int bytes, int timeout)
-{
-#if 0
- fd_set rfds;
- struct timeval tv;
- int retval;
- int s;
-#endif
- int len, rlen;
+// read data from the encrypted layer.
+int client_read_sslbuffer(StrBuf *buf, int timeout) {
+ char sbuf[16384]; // OpenSSL communicates in 16k blocks, so let's speak its native tongue.
+ int rlen;
char junk[1];
+ SSL *pssl = THREADSSL;
- len = 0;
- while (len < bytes) {
-#if 0
- /*
- * This code is disabled because we don't need it when
- * using blocking reads (which we are). -IO
- */
- FD_ZERO(&rfds);
- s = BIO_get_fd(THREADSSL->rbio, NULL);
- FD_SET(s, &rfds);
- tv.tv_sec = timeout;
- tv.tv_usec = 0;
-
- retval = select(s + 1, &rfds, NULL, NULL, &tv);
-
- if (FD_ISSET(s, &rfds) == 0) {
- return (0);
- }
+ if (pssl == NULL) return(-1);
-#endif
- if (SSL_want_read(THREADSSL)) {
- if ((SSL_write(THREADSSL, junk, 0)) < 1) {
- lprintf(9, "SSL_write in client_read: %s\n", ERR_reason_error_string(ERR_get_error()));
+ while (1) {
+ if (SSL_want_read(pssl)) {
+ if ((SSL_write(pssl, junk, 0)) < 1) {
+ syslog(LOG_WARNING, "SSL_write in client_read");
}
}
- rlen = SSL_read(THREADSSL, &buf[len], bytes - len);
+ rlen = SSL_read(pssl, sbuf, sizeof(sbuf));
if (rlen < 1) {
long errval;
- errval = SSL_get_error(THREADSSL, rlen);
- if (errval == SSL_ERROR_WANT_READ ||
- errval == SSL_ERROR_WANT_WRITE) {
- sleep(1);
+ errval = SSL_get_error(pssl, rlen);
+ if (errval == SSL_ERROR_WANT_READ || errval == SSL_ERROR_WANT_WRITE) {
+ sleeeeeeeeeep(1);
continue;
}
- lprintf(9, "SSL_read got error %ld\n", errval);
+ syslog(LOG_WARNING, "SSL_read in client_read: %s", ERR_reason_error_string(ERR_get_error()));
endtls();
- return (0);
+ return (-1);
}
- len += rlen;
+ StrBufAppendBufPlain(buf, sbuf, rlen, 0);
+ return rlen;
}
- return (1);
+ return (0);
}
-
#endif /* HAVE_OPENSSL */