When checking to see whether we have to rebind a new key and/or
[citadel.git] / webcit / crypto.c
index 0d0f080b0dfed63f0a17cf48c3ff9a7b1db720a6..bd08639026d7e721bcd284ac8ec7fa1955820f2f 100644 (file)
 #include "webcit.h"
 #include "webserver.h"
 
-/* where to find the keys */
-#define        CTDL_CRYPTO_DIR         ctdl_key_dir
-#define CTDL_KEY_PATH          file_crpt_file_key
-#define CTDL_CSR_PATH          file_crpt_file_csr
-#define CTDL_CER_PATH          file_crpt_file_cer
-#define SIGN_DAYS              3650                    // how long our self-signed certificate should live
 
 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;
 
 pthread_key_t ThreadSSL;       // Per-thread SSL context
@@ -31,70 +27,30 @@ void shutdown_ssl(void) {
 }
 
 
-void generate_key(char *keyfilename) {
-       int ret = 0;
-       RSA *rsa = NULL;
-       BIGNUM *bne = NULL;
-       int bits = 2048;
-       unsigned long e = RSA_F4;
-       FILE *fp;
-
-       if (access(keyfilename, R_OK) == 0) {           // We already have a key -- don't generate a new one.
-               return;
-       }
-
-       syslog(LOG_INFO, "crypto: generating RSA key pair");
-       // generate rsa key
-       bne = BN_new();
-       ret = BN_set_word(bne,e);
-       if (ret != 1) {
-               goto free_all;
+// 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) {
+       if (IsEmptyStr(key_file)) {
+               snprintf(key_file, sizeof key_file, "%s/keys/citadel.key", ctdl_dir);
        }
-       rsa = RSA_new();
-       ret = RSA_generate_key_ex(rsa, bits, bne, NULL);
-       if (ret != 1) {
-               goto free_all;
+       if (IsEmptyStr(cert_file)) {
+               snprintf(cert_file, sizeof key_file, "%s/keys/citadel.cer", ctdl_dir);
        }
 
-       // write the key file
-       fp = fopen(keyfilename, "w");
-       if (fp != NULL) {
-               chmod(file_crpt_file_key, 0600);
-               if (PEM_write_RSAPrivateKey(fp, // the file
-                                       rsa,    // the key
-                                       NULL,   // no enc
-                                       NULL,   // no passphrase
-                                       0,      // no passphrase
-                                       NULL,   // no callback
-                                       NULL    // no callback
-               ) != 1) {
-                       syslog(LOG_ERR, "crypto: cannot write key: %s", ERR_reason_error_string(ERR_get_error()));
-                       unlink(keyfilename);
-               }
-               fclose(fp);
-       }
+       syslog(LOG_DEBUG, "crypto: [re]installing key \"%s\" and certificate \"%s\"", key_file, cert_file);
+
+       SSL_CTX_use_certificate_chain_file(ssl_ctx, cert_file);
+       SSL_CTX_use_PrivateKey_file(ssl_ctx, key_file, SSL_FILETYPE_PEM);
 
-       // Free the memory we used
-free_all:
-       RSA_free(rsa);
-       BN_free(bne);
+       if ( !SSL_CTX_check_private_key(ssl_ctx) ) {
+               syslog(LOG_WARNING, "crypto: cannot install certificate: %s", ERR_reason_error_string(ERR_get_error()));
+       }
 }
 
 
 // initialize ssl engine, load certs and initialize openssl internals
 void init_ssl(void) {
        const SSL_METHOD *ssl_method;
-       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];
-       int rv = 0;
 
 #ifndef OPENSSL_NO_EGD
        if (!access("/var/run/egd-pool", F_OK)) {
@@ -122,216 +78,43 @@ void init_ssl(void) {
                return;
        }
 
-       CRYPTO_set_locking_callback(ssl_lock);
-       CRYPTO_set_id_callback(id_callback);
-
-       // 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);
-               rv = symlink(buf, CTDL_KEY_PATH);
-               if (!rv) {
-                       syslog(LOG_DEBUG, "%s", strerror(errno));
-               }
-               sprintf(buf, "%s/keys/citadel.csr", ctdlport);
-               rv = symlink(buf, CTDL_CSR_PATH);
-               if (!rv) {
-                       syslog(LOG_DEBUG, "%s", strerror(errno));
-               }
-               sprintf(buf, "%s/keys/citadel.cer", ctdlport);
-               rv = symlink(buf, CTDL_CER_PATH);
-               if (!rv) {
-                       syslog(LOG_DEBUG, "%s", strerror(errno));
-               }
-       }
-
-       // If we still don't have a private key, generate one.
-       generate_key(CTDL_KEY_PATH);
-
-       // If there is no certificate file on disk, we will be generating a self-signed certificate
-       // in the next step.  Therefore, if we have neither a CSR nor a certificate, generate
-       // the CSR in this step so that the next step may commence.
-       if ( (access(CTDL_CER_PATH, R_OK) != 0) && (access(CTDL_CSR_PATH, R_OK) != 0) ) {
-               syslog(LOG_INFO, "Generating a certificate signing request.");
-
-               // 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) {
-                                       const char *env;
-                                       // 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
-                                       env = getenv("O");
-                                       if (env == NULL) {
-                                               env = "Organization name";
-                                       }
-
-                                       X509_NAME_add_entry_by_txt(
-                                               name, "O",
-                                               MBSTRING_ASC, 
-                                               (unsigned char*)env, 
-                                               -1, -1, 0
-                                       );
-
-                                       env = getenv("OU");
-                                       if (env == NULL) {
-                                               env = "Citadel server";
-                                       }
-
-                                       X509_NAME_add_entry_by_txt(
-                                               name, "OU",
-                                               MBSTRING_ASC, 
-                                               (unsigned char*)env, 
-                                               -1, -1, 0
-                                       );
-
-                                       env = getenv("CN");
-                                       if (env == NULL)
-                                               env = "*";
-
-                                       X509_NAME_add_entry_by_txt(
-                                               name, "CN",
-                                               MBSTRING_ASC, 
-                                               (unsigned char*)env,
-                                               -1, -1, 0
-                                       );
-                               
-                                       X509_REQ_set_subject_name(req, name);
-
-                                       // Sign the CSR
-                                       if (!X509_REQ_sign(req, pk, EVP_md5())) {
-                                               syslog(LOG_WARNING, "X509_REQ_sign(): error");
-                                       }
-                                       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);
-                                               }
-                                               else {
-                                                       syslog(LOG_WARNING, "Cannot write key: %s", CTDL_CSR_PATH);
-                                                       ShutDownWebcit();
-                                                       exit(0);
-                                               }
-                                       }
-
-                                       X509_REQ_free(req);
-                               }
-                       }
-                       RSA_free(rsa);
-               }
-               else {
-                       syslog(LOG_WARNING, "Unable to read private key.");
-               }
-       }
-
-       // Generate a self-signed certificate if we don't have one.
-       if (access(CTDL_CER_PATH, R_OK) != 0) {
-               syslog(LOG_INFO, "Generating a self-signed certificate.\n");
+       // Now try to bind to the key and certificate.
+       bind_to_key_and_certificate();
+}
 
-               // 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);
-               }
 
-               // 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);
-                       }
+// 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;
 
-                       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, X509_REQ_get_subject_name(req));
-                                       X509_set_subject_name(cer, X509_REQ_get_subject_name(req));
-                                       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())) {
-                                               syslog(LOG_WARNING, "X509_sign(): error");
-                                       }
-                                       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);
-                                               }
-                                               else {
-                                                       syslog(LOG_WARNING, "Cannot write key: %s", CTDL_CER_PATH);
-                                                       ShutDownWebcit();
-                                                       exit(0);
-                                               }
-                                       }
-                                       X509_free(cer);
-                               }
-                       }
-                       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) ) {
-               syslog(LOG_WARNING, "crypto: cannot install certificate: %s", 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;
        }
 }
 
 
 // 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) {
@@ -357,30 +140,30 @@ int starttls(int sock) {
                errval = SSL_get_error(newssl, retval);
                ssl_error_reason = ERR_reason_error_string(ERR_get_error());
                if (ssl_error_reason == NULL) {
-                       syslog(LOG_WARNING, "SSL_accept failed: errval=%ld, retval=%d %s", errval, retval, strerror(errval));
+                       syslog(LOG_WARNING, "first SSL_accept failed: errval=%ld, retval=%d %s", errval, retval, strerror(errval));
                }
                else {
-                       syslog(LOG_WARNING, "SSL_accept failed: %s", ssl_error_reason);
+                       syslog(LOG_WARNING, "first SSL_accept failed: %s", ssl_error_reason);
                }
-               sleeeeeeeeeep(1);
-               retval = SSL_accept(newssl);
-       }
-       if (retval < 1) {
-               long errval;
-               const char *ssl_error_reason = NULL;
-
-               errval = SSL_get_error(newssl, retval);
-               ssl_error_reason = ERR_reason_error_string(ERR_get_error());
-               if (ssl_error_reason == NULL) {
-                       syslog(LOG_WARNING, "SSL_accept failed: errval=%ld, retval=%d (%s)", errval, retval, strerror(errval));
-               }
-               else {
-                       syslog(LOG_WARNING, "SSL_accept failed: %s", ssl_error_reason);
-               }
-               SSL_free(newssl);
-               newssl = NULL;
-               return(4);
+               // sleeeeeeeeeep(1);
+               // retval = SSL_accept(newssl);
        }
+       // if (retval < 1) {
+               // long errval;
+               // const char *ssl_error_reason = NULL;
+// 
+               // errval = SSL_get_error(newssl, retval);
+               // ssl_error_reason = ERR_reason_error_string(ERR_get_error());
+               // if (ssl_error_reason == NULL) {
+                       // syslog(LOG_WARNING, "second SSL_accept failed: errval=%ld, retval=%d (%s)", errval, retval, strerror(errval));
+               // }
+               // else {
+                       // syslog(LOG_WARNING, "second SSL_accept failed: %s", ssl_error_reason);
+               // }
+               // SSL_free(newssl);
+               // newssl = NULL;
+               // return(4);
+       // }
        else {
                syslog(LOG_INFO, "SSL_accept success");
        }
@@ -443,7 +226,7 @@ int client_write_ssl(const StrBuf *Buf) {
                                sleeeeeeeeeep(1);
                                continue;
                        }
-                       syslog(LOG_WARNING, "SSL_write got error %ld, ret %d", errval, retval);
+                       syslog(LOG_WARNING, "SSL_write: %s", ERR_reason_error_string(ERR_get_error()));
                        if (retval == -1) {
                                syslog(LOG_WARNING, "errno is %d\n", errno);
                        }
@@ -480,7 +263,7 @@ int client_read_sslbuffer(StrBuf *buf, int timeout) {
                                sleeeeeeeeeep(1);
                                continue;
                        }
-                       syslog(LOG_WARNING, "SSL_read got error %ld", errval);
+                       syslog(LOG_WARNING, "SSL_read in client_read: %s", ERR_reason_error_string(ERR_get_error()));
                        endtls();
                        return (-1);
                }