Call endtls() when an HTTP session ends normally -- not
[citadel.git] / webcit / crypto.c
index 6c270ad5b75bad57bd667163778014946933b27b..cb6e22a20d9336599090c766a07a013095518a44 100644 (file)
@@ -1,84 +1,46 @@
-/* $Id$ */
+/*
+ * $Id$
+ */
+/**
+ * \defgroup https  Provides HTTPS, when the OpenSSL library is available.
+ * \ingroup WebcitHttpServer 
+ */
 
+/*@{*/
+#include "config.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         "./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
-#define CIT_CIPHERS    "ALL:RC4+RSA:+SSLv2:@STRENGTH"  /* see ciphers(1) */
-
-SSL_CTX *ssl_ctx;              /* SSL context */
-pthread_mutex_t **SSLCritters; /* Things needing locking */
-
-pthread_key_t ThreadSSL;       /* Per-thread SSL context */
-
+/** \todo dirify */
+/** where to find the keys */
+#define        CTDL_CRYPTO_DIR         "./keys" 
+#define CTDL_KEY_PATH          CTDL_CRYPTO_DIR "/citadel.key" /**< the key */
+#define CTDL_CSR_PATH          CTDL_CRYPTO_DIR "/citadel.csr" /**< the csr file */
+#define CTDL_CER_PATH          CTDL_CRYPTO_DIR "/citadel.cer" /**< the cer file */
+#define SIGN_DAYS              365 /**< how long our certificate should live */
+
+SSL_CTX *ssl_ctx;              /**< SSL context */
+pthread_mutex_t **SSLCritters; /**< Things needing locking */
+
+pthread_key_t ThreadSSL;       /**< Per-thread SSL context */
+
+/**
+ * \brief what?????
+ * \return thread id??? 
+ */
 static unsigned long id_callback(void)
 {
        return (unsigned long) pthread_self();
 }
 
- /*
-  * Set up the cert things on the server side. We do need both the
-  * private key (in key_file) and the cert (in cert_file).
-  * Both files may be identical.
-  *
-  * This function is taken from OpenSSL apps/s_cb.c
-  */
-
-static int ctdl_install_certificate(SSL_CTX * ctx,
-                         const char *cert_file, const char *key_file)
-{
-       if (cert_file != NULL) {
-               if (SSL_CTX_use_certificate_file(ctx, cert_file,
-                                                SSL_FILETYPE_PEM) <= 0) {
-                       lprintf(3, "unable to get certificate from '%s'",
-                               cert_file);
-                       return (0);
-               }
-               if (key_file == NULL)
-                       key_file = cert_file;
-               if (SSL_CTX_use_PrivateKey_file(ctx, key_file,
-                                               SSL_FILETYPE_PEM) <= 0) {
-                       lprintf(3, "unable to get private key from '%s'",
-                               key_file);
-                       return (0);
-               }
-               /* Now we know that a key and cert have been set against
-                * the SSL context */
-               if (!SSL_CTX_check_private_key(ctx)) {
-                       lprintf(3,
-                               "Private key does not match the certificate public key");
-                       return (0);
-               }
-       }
-       return (1);
-}
-
-
+/**
+ * \brief initialize ssl engine
+ * load certs and initialize openssl internals
+ */
 void init_ssl(void)
 {
        SSL_METHOD *ssl_method;
-       DH *dh;
        RSA *rsa=NULL;
        X509_REQ *req = NULL;
        X509 *cer = NULL;
@@ -86,6 +48,7 @@ void init_ssl(void)
        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");
@@ -109,14 +72,14 @@ void init_ssl(void)
                        if (!SSLCritters[a]) {
                                lprintf(1,
                                        "citserver: can't allocate memory!!\n");
-                               /* Nothing's been initialized, just die */
+                               /** Nothing's been initialized, just die */
                                exit(1);
                        }
                        pthread_mutex_init(SSLCritters[a], NULL);
                }
        }
 
-       /*
+       /**
         * Initialize SSL transport layer
         */
        SSL_library_init();
@@ -127,63 +90,42 @@ void init_ssl(void)
                        ERR_reason_error_string(ERR_get_error()));
                return;
        }
-       if (!(SSL_CTX_set_cipher_list(ssl_ctx, CIT_CIPHERS))) {
-               lprintf(3, "SSL: No ciphers available\n");
-               SSL_CTX_free(ssl_ctx);
-               ssl_ctx = NULL;
-               return;
-       }
-#if 0
-#if SSLEAY_VERSION_NUMBER >= 0x00906000L
-       SSL_CTX_set_mode(ssl_ctx, SSL_CTX_get_mode(ssl_ctx) |
-                        SSL_MODE_AUTO_RETRY);
-#endif
-#endif
 
        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;
-               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.
+       /**
+        * Get our certificates in order. \todo dirify. this is a setup job.
         * First, create the key/cert directory if it's not there already...
         */
        mkdir(CTDL_CRYPTO_DIR, 0700);
 
-       /*
-        * Generate a key pair if we don't have one.
+       /**
+        * 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). \todo dirify
+        */
+       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 */
+               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()));
@@ -192,13 +134,13 @@ void init_ssl(void)
                        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 */
+                               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()));
@@ -210,13 +152,13 @@ void init_ssl(void)
                }
        }
 
-       /*
+       /**
         * 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
@@ -230,20 +172,20 @@ void init_ssl(void)
 
                if (rsa) {
 
-                       /* Create a public key from the private key */
+                       /** 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 */
+                                       /** 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 */
+                                       /** Tell it who we are */
 
-                                       /*
+                                       /* \todo whats this?
                                        X509_NAME_add_entry_by_txt(name, "C",
                                                MBSTRING_ASC, "US", -1, -1, 0);
 
@@ -265,12 +207,12 @@ void init_ssl(void)
                                
                                        X509_REQ_set_subject_name(req, name);
 
-                                       /* Sign the CSR */
+                                       /** Sign the CSR */
                                        if (!X509_REQ_sign(req, pk, EVP_md5())) {
                                                lprintf(3, "X509_REQ_sign(): error\n");
                                        }
                                        else {
-                                               /* Write it to disk. */ 
+                                               /** Write it to disk. */        
                                                fp = fopen(CTDL_CSR_PATH, "w");
                                                if (fp != NULL) {
                                                        chmod(CTDL_CSR_PATH, 0600);
@@ -293,13 +235,13 @@ void init_ssl(void)
 
 
 
-       /*
+       /**
         * 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");
 
-               /* Same deal as before: always read the key from disk because
+               /** 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");
@@ -308,7 +250,7 @@ void init_ssl(void)
                        fclose(fp);
                }
 
-               /* This also holds true for the CSR. */
+               /** This also holds true for the CSR. */
                req = NULL;
                cer = NULL;
                pk = NULL;
@@ -326,20 +268,22 @@ void init_ssl(void)
                        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_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 */
+                                       /** Sign the cert */
                                        if (!X509_sign(cer, pk, EVP_md5())) {
                                                lprintf(3, "X509_sign(): error\n");
                                        }
                                        else {
-                                               /* Write it to disk. */ 
+                                               /** Write it to disk. */        
                                                fp = fopen(CTDL_CER_PATH, "w");
                                                if (fp != NULL) {
                                                        chmod(CTDL_CER_PATH, 0600);
@@ -355,23 +299,25 @@ void init_ssl(void)
                }
        }
 
-
-       /*
+       /**
         * 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.
         */
-       if (ctdl_install_certificate(ssl_ctx,
-                       CTDL_CER_PATH,
-                       CTDL_KEY_PATH) != 1)
-       {
+       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()));
        }
-
+       
 }
 
 
-/*
- * starttls() starts SSL/TLS encryption for the current session.
+/**
+ * \brief starts SSL/TLS encryption for the current session.
+ * \param sock the socket connection
+ * \return Zero if the SSL/TLS handshake succeeded, non-zero otherwise.
  */
 int starttls(int sock) {
        int retval, bits, alg_bits;
@@ -395,7 +341,7 @@ int starttls(int sock) {
        }
        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.
@@ -424,23 +370,41 @@ int starttls(int sock) {
 
 
 
-/*
- * endtls() shuts down the TLS connection
+/**
+ * \brief shuts down the TLS connection
  *
  * WARNING:  This may make your session vulnerable to a known plaintext
  * attack in the current implmentation.
  */
 void endtls(void)
 {
+       SSL_CTX *ctx = NULL;
+
+       if (THREADSSL == NULL) return;
+
        lprintf(5, "Ending SSL/TLS\n");
        SSL_shutdown(THREADSSL);
+       ctx = SSL_get_SSL_CTX(THREADSSL);
+
+       /** I don't think this is needed, and it crashes the server anyway
+        *
+        *      if (ctx != NULL) {
+        *              lprintf(9, "Freeing CTX at %x\n", (int)ctx );
+        *              SSL_CTX_free(ctx);
+        *      }
+        */
+
        SSL_free(THREADSSL);
        pthread_setspecific(ThreadSSL, NULL);
 }
 
 
-/*
- * ssl_lock() callback for OpenSSL mutex locks
+/**
+ * \brief callback for OpenSSL mutex locks
+ * \param mode which mode??????
+ * \param n  how many???
+ * \param file which filename ???
+ * \param line what line????
  */
 void ssl_lock(int mode, int n, const char *file, int line)
 {
@@ -450,8 +414,10 @@ void ssl_lock(int mode, int n, const char *file, int line)
                pthread_mutex_unlock(SSLCritters[n]);
 }
 
-/*
- * client_write_ssl() Send binary data to the client encrypted.
+/**
+ * \brief Send binary data to the client encrypted.
+ * \param buf chars to send to the client
+ * \param nbytes how many chars
  */
 void client_write_ssl(char *buf, int nbytes)
 {
@@ -459,16 +425,18 @@ void client_write_ssl(char *buf, int nbytes)
        int nremain;
        char junk[1];
 
+       if (THREADSSL == NULL) return;
+
        nremain = nbytes;
 
        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()));
+                               lprintf(9, "SSL_read in client_write: %s\n",
+                                               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;
 
@@ -479,10 +447,10 @@ void client_write_ssl(char *buf, int nbytes)
                                continue;
                        }
                        lprintf(9, "SSL_write got error %ld, ret %d\n", errval, retval);
-                       if (retval == -1)
+                       if (retval == -1) {
                                lprintf(9, "errno is %d\n", errno);
+                       }
                        endtls();
-                       client_write(&buf[nbytes - nremain], nremain);
                        return;
                }
                nremain -= retval;
@@ -490,8 +458,12 @@ void client_write_ssl(char *buf, int nbytes)
 }
 
 
-/*
- * client_read_ssl() - read data from the encrypted layer.
+/**
+ * \brief read data from the encrypted layer.
+ * \param buf charbuffer to read to 
+ * \param bytes how many
+ * \param timeout how long should we wait?
+ * \returns what???
  */
 int client_read_ssl(char *buf, int bytes, int timeout)
 {
@@ -504,10 +476,12 @@ int client_read_ssl(char *buf, int bytes, int timeout)
        int len, rlen;
        char junk[1];
 
+       if (THREADSSL == NULL) return(0);
+
        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
                 */
@@ -541,8 +515,7 @@ int client_read_ssl(char *buf, int bytes, int timeout)
                        }
                        lprintf(9, "SSL_read got error %ld\n", errval);
                        endtls();
-                       return (client_read_to
-                               (&buf[len], bytes - len, timeout));
+                       return (0);
                }
                len += rlen;
        }
@@ -551,3 +524,4 @@ int client_read_ssl(char *buf, int bytes, int timeout)
 
 
 #endif                         /* HAVE_OPENSSL */
+/*@}*/