path: root/camel/camel-tcp-stream-openssl.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 *  Authors: Jeffrey Stedfast <fejj@ximian.com>
 *
 *  Copyright 2001 Ximian, Inc. (www.ximian.com)
 *
 *  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 Street #330, Boston, MA 02111-1307, USA.
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef HAVE_OPENSSL

#include "camel-tcp-stream-openssl.h"

#include <openssl/ssl.h>
#include <openssl/x509.h>
#include <openssl/err.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include "camel-session.h"
#include "camel-service.h"
#include "camel-operation.h"
#ifdef ENABLE_THREADS
#include <pthread.h>
#endif

static CamelTcpStreamClass *parent_class = NULL;

/* Returns the class for a CamelTcpStreamOpenSSL */
#define CTSR_CLASS(so) CAMEL_TCP_STREAM_OPENSSL_CLASS (CAMEL_OBJECT_GET_CLASS (so))

static ssize_t stream_read (CamelStream *stream, char *buffer, size_t n);
static ssize_t stream_write (CamelStream *stream, const char *buffer, size_t n);
static int stream_flush  (CamelStream *stream);
static int stream_close  (CamelStream *stream);

static int stream_connect (CamelTcpStream *stream, struct hostent *host, int port);
static int stream_getsockopt (CamelTcpStream *stream, CamelSockOptData *data);
static int stream_setsockopt (CamelTcpStream *stream, const CamelSockOptData *data);
static gpointer stream_get_socket (CamelTcpStream *stream);

struct _CamelTcpStreamOpenSSLPrivate {
    int sockfd;
    SSL *ssl;
    
    CamelService *service;
    char *expected_host;
};

static void
camel_tcp_stream_openssl_class_init (CamelTcpStreamOpenSSLClass *camel_tcp_stream_openssl_class)
{
    CamelTcpStreamClass *camel_tcp_stream_class =
        CAMEL_TCP_STREAM_CLASS (camel_tcp_stream_openssl_class);
    CamelStreamClass *camel_stream_class =
        CAMEL_STREAM_CLASS (camel_tcp_stream_openssl_class);
    
    parent_class = CAMEL_TCP_STREAM_CLASS (camel_type_get_global_classfuncs (camel_tcp_stream_get_type ()));
    
    /* virtual method overload */
    camel_stream_class->read = stream_read;
    camel_stream_class->write = stream_write;
    camel_stream_class->flush = stream_flush;
    camel_stream_class->close = stream_close;
    
    camel_tcp_stream_class->connect = stream_connect;
    camel_tcp_stream_class->getsockopt = stream_getsockopt;
    camel_tcp_stream_class->setsockopt = stream_setsockopt;
    camel_tcp_stream_class->get_socket = stream_get_socket;
}

static void
camel_tcp_stream_openssl_init (gpointer object, gpointer klass)
{
    CamelTcpStreamOpenSSL *stream = CAMEL_TCP_STREAM_OPENSSL (object);
    
    stream->priv = g_new0 (struct _CamelTcpStreamOpenSSLPrivate, 1);
    stream->priv->sockfd = -1;
}

static void
camel_tcp_stream_openssl_finalize (CamelObject *object)
{
    CamelTcpStreamOpenSSL *stream = CAMEL_TCP_STREAM_OPENSSL (object);
    
    if (stream->priv->ssl) {
        SSL_shutdown (stream->priv->ssl);
        
        if (stream->priv->ssl->ctx) {
            SSL_CTX_free (stream->priv->ssl->ctx);
        }
        
        SSL_free (stream->priv->ssl);
    }
    
    if (stream->priv->sockfd != -1)
        close (stream->priv->sockfd);
    
    g_free (stream->priv->expected_host);
    
    g_free (stream->priv);
}


CamelType
camel_tcp_stream_openssl_get_type (void)
{
    static CamelType type = CAMEL_INVALID_TYPE;
    
    if (type == CAMEL_INVALID_TYPE) {
        type = camel_type_register (camel_tcp_stream_get_type (),
                        "CamelTcpStreamOpenSSL",
                        sizeof (CamelTcpStreamOpenSSL),
                        sizeof (CamelTcpStreamOpenSSLClass),
                        (CamelObjectClassInitFunc) camel_tcp_stream_openssl_class_init,
                        NULL,
                        (CamelObjectInitFunc) camel_tcp_stream_openssl_init,
                        (CamelObjectFinalizeFunc) camel_tcp_stream_openssl_finalize);
    }
    
    return type;
}


/**
 * camel_tcp_stream_openssl_new:
 * @service: camel service
 * @expected_host: host that the stream is expecting to connect with.
 *
 * Since the SSL certificate authenticator may need to prompt the
 * user, a CamelService is needed. @expected_host is needed as a
 * protection against an MITM attack.
 *
 * Return value: a tcp stream
 **/
CamelStream *
camel_tcp_stream_openssl_new (CamelService *service, const char *expected_host)
{
    CamelTcpStreamOpenSSL *stream;
    
    stream = CAMEL_TCP_STREAM_OPENSSL (camel_object_new (camel_tcp_stream_openssl_get_type ()));
    
    stream->priv->service = service;
    stream->priv->expected_host = g_strdup (expected_host);
    
    return CAMEL_STREAM (stream);
}

static void
errlib_error_to_errno (int ret)
{
    long error;
    
    error = ERR_get_error ();
    if (error == 0) {
        if (ret == 0)
            errno = EINVAL; /* unexpected EOF */
        /* otherwise errno should be set */
    } else {
        /* ok, we get the shaft now. */
        errno = EINTR;
    }
}

static void
ssl_error_to_errno (SSL *ssl, int ret)
{
    /* hm, a CamelException might be useful right about now! */
    
    switch (SSL_get_error (ssl, ret)) {
    case SSL_ERROR_NONE:
        errno = 0;
        return;
    case SSL_ERROR_ZERO_RETURN:
        /* this one does not map well at all */
        errno = EINVAL;
        return;
    case SSL_ERROR_WANT_READ: /* non-fatal; retry */
    case SSL_ERROR_WANT_WRITE:  /* non-fatal; retry */
    case SSL_ERROR_WANT_X509_LOOKUP: /* non-fatal; retry */
        errno = EAGAIN;
        return;
    case SSL_ERROR_SYSCALL:
        errlib_error_to_errno (ret);
        return;
    case SSL_ERROR_SSL:
        errlib_error_to_errno (-1);
        return;
    }
}

static int
my_SSL_read (SSL *ssl, void *buf, int num)
{
    int ret;

    do
        ret = SSL_read (ssl, buf, num);
    while (ret < 0 && (SSL_get_error (ssl, ret) == SSL_ERROR_WANT_READ ||
               SSL_get_error (ssl, ret) == SSL_ERROR_WANT_WRITE));
    return ret;
}

static ssize_t
stream_read (CamelStream *stream, char *buffer, size_t n)
{
    CamelTcpStreamOpenSSL *tcp_stream_openssl = CAMEL_TCP_STREAM_OPENSSL (stream);
    ssize_t nread;
    int cancel_fd;
    
    if (camel_operation_cancel_check (NULL)) {
        errno = EINTR;
        return -1;
    }
    
    cancel_fd = camel_operation_cancel_fd (NULL);
    if (cancel_fd == -1) {
        do {
            nread = my_SSL_read (tcp_stream_openssl->priv->ssl, buffer, n);
        } while (nread == -1 && errno == EINTR);
    } else {
        int flags, fdmax;
        fd_set rdset;
        
        flags = fcntl (tcp_stream_openssl->priv->sockfd, F_GETFL);
        fcntl (tcp_stream_openssl->priv->sockfd, F_SETFL, flags | O_NONBLOCK);
        
        do {
            nread = my_SSL_read (tcp_stream_openssl->priv->ssl, buffer, n);
            
            if (nread == 0)
                return nread;
            
            if (nread == -1 && errno == EAGAIN) {
                FD_ZERO (&rdset);
                FD_SET (tcp_stream_openssl->priv->sockfd, &rdset);
                FD_SET (cancel_fd, &rdset);
                fdmax = MAX (tcp_stream_openssl->priv->sockfd, cancel_fd) + 1;
                
                select (fdmax, &rdset, 0, 0, NULL);
                if (FD_ISSET (cancel_fd, &rdset)) {
                    fcntl (tcp_stream_openssl->priv->sockfd, F_SETFL, flags);
                    errno = EINTR;
                    return -1;
                }
            }
        } while (nread == -1 && errno == EAGAIN);
        
        fcntl (tcp_stream_openssl->priv->sockfd, F_SETFL, flags);
    }
    
    if (nread == -1)
        ssl_error_to_errno (tcp_stream_openssl->priv->ssl, -1);
    
    return nread;
}

static int
my_SSL_write (SSL *ssl, const void *buf, int num)
{
    int ret;

    do
        ret = SSL_write (ssl, buf, num);
    while (ret < 0 && (SSL_get_error (ssl, ret) == SSL_ERROR_WANT_READ ||
               SSL_get_error (ssl, ret) == SSL_ERROR_WANT_WRITE));
    return ret;
}

static ssize_t
stream_write (CamelStream *stream, const char *buffer, size_t n)
{
    CamelTcpStreamOpenSSL *tcp_stream_openssl = CAMEL_TCP_STREAM_OPENSSL (stream);
    ssize_t w, written = 0;
    int cancel_fd;
    
    if (camel_operation_cancel_check (NULL)) {
        errno = EINTR;
        return -1;
    }
    
    cancel_fd = camel_operation_cancel_fd (NULL);
    if (cancel_fd == -1) {
        do {
            written = my_SSL_write (tcp_stream_openssl->priv->ssl, buffer, n);
        } while (written == -1 && errno == EINTR);
    } else {
        fd_set rdset, wrset;
        int flags, fdmax;
        
        flags = fcntl (tcp_stream_openssl->priv->sockfd, F_GETFL);
        fcntl (tcp_stream_openssl->priv->sockfd, F_SETFL, flags | O_NONBLOCK);
        
        fdmax = MAX (tcp_stream_openssl->priv->sockfd, cancel_fd) + 1;
        do {
            FD_ZERO (&rdset);
            FD_ZERO (&wrset);
            FD_SET (tcp_stream_openssl->priv->sockfd, &wrset);
            FD_SET (cancel_fd, &rdset);
            
            select (fdmax, &rdset, &wrset, 0, NULL);
            if (FD_ISSET (cancel_fd, &rdset)) {
                fcntl (tcp_stream_openssl->priv->sockfd, F_SETFL, flags);
                errno = EINTR;
                return -1;
            }
            
            w = my_SSL_write (tcp_stream_openssl->priv->ssl, buffer + written, n - written);
            if (w > 0)
                written += w;
        } while (w != -1 && written < n);
        
        fcntl (tcp_stream_openssl->priv->sockfd, F_SETFL, flags);
        if (w == -1)
            written = -1;
    }
    
    if (written == -1)
        ssl_error_to_errno (tcp_stream_openssl->priv->ssl, -1);
    
    return written;
}

static int
stream_flush (CamelStream *stream)
{
    return fsync (((CamelTcpStreamOpenSSL *)stream)->priv->sockfd);
}


static void
close_ssl_connection (SSL *ssl)
{
    if (ssl) {
        SSL_shutdown (ssl);
        
        if (ssl->ctx)
            SSL_CTX_free (ssl->ctx);
        
        SSL_free (ssl);
    }
}

static int
stream_close (CamelStream *stream)
{
    close_ssl_connection (((CamelTcpStreamOpenSSL *)stream)->priv->ssl);
    ((CamelTcpStreamOpenSSL *)stream)->priv->ssl = NULL;
    
    if (close (((CamelTcpStreamOpenSSL *)stream)->priv->sockfd) == -1)
        return -1;
    
    ((CamelTcpStreamOpenSSL *)stream)->priv->sockfd = -1;
    return 0;
}

/* this is a 'cancellable' connect, cancellable from camel_operation_cancel etc */
/* returns -1 & errno == EINTR if the connection was cancelled */
static int
socket_connect (struct hostent *h, int port)
{
    struct sockaddr_in sin;
    int fd;
    int ret;
    socklen_t len;
    struct timeval tv;
    int cancel_fd;
    
    /* see if we're cancelled yet */
    if (camel_operation_cancel_check (NULL)) {
        errno = EINTR;
        return -1;
    }
    
    /* setup connect, we do it using a nonblocking socket so we can poll it */
    sin.sin_port = htons (port);
    sin.sin_family = h->h_addrtype;
    memcpy (&sin.sin_addr, h->h_addr, sizeof (sin.sin_addr));
    
    fd = socket (h->h_addrtype, SOCK_STREAM, 0);
    
    cancel_fd = camel_operation_cancel_fd (NULL);
    if (cancel_fd == -1) {
        ret = connect (fd, (struct sockaddr *)&sin, sizeof (sin));
        if (ret == -1) {
            close (fd);
            return -1;
        }
        
        return fd;
    } else {
        fd_set rdset, wrset;
        int flags, fdmax;
        
        flags = fcntl (fd, F_GETFL);
        fcntl (fd, F_SETFL, flags | O_NONBLOCK);
        
        ret = connect (fd, (struct sockaddr *)&sin, sizeof (sin));
        if (ret == 0) {
            fcntl (fd, F_SETFL, flags);
            return fd;
        }
        
        if (errno != EINPROGRESS) {
            close (fd);
            return -1;
        }
        
        FD_ZERO (&rdset);
        FD_ZERO (&wrset);
        FD_SET (fd, &wrset);
        FD_SET (cancel_fd, &rdset);
        fdmax = MAX (fd, cancel_fd) + 1;
        tv.tv_usec = 0;
        tv.tv_sec = 60 * 4;
        
        if (select (fdmax, &rdset, &wrset, 0, &tv) == 0) {
            close (fd);
            errno = ETIMEDOUT;
            return -1;
        }
        
        if (cancel_fd != -1 && FD_ISSET (cancel_fd, &rdset)) {
            close (fd);
            errno = EINTR;
            return -1;
        } else {
            len = sizeof (int);
            
            if (getsockopt (fd, SOL_SOCKET, SO_ERROR, &ret, &len) == -1) {
                close (fd);
                return -1;
            }
            
            if (ret != 0) {
                close (fd);
                errno = ret;
                return -1;
            }
        }
        
        fcntl (fd, F_SETFL, flags);
    }
    
    return fd;
}

static void
save_ssl_cert (const char *certid)
{
    char *path, *filename;
    struct stat st;
    int fd;
    
    path = g_strdup_printf ("%s/.camel_certs", getenv ("HOME"));
    if (mkdir (path, 0700) == -1) {
        if (errno != EEXIST)
            return;
        
        if (stat (path, &st) == -1)
            return;
        
        if (!S_ISDIR (st.st_mode))
            return;
    }
    
    filename = g_strdup_printf ("%s/%s", path, certid);
    g_free (path);
    
    fd = open (filename, O_WRONLY | O_CREAT);
    if (fd != -1)
        close (fd);
    
    g_free (filename);
}

static gboolean
ssl_cert_is_saved (const char *certid)
{
    char *filename;
    struct stat st;
    int ret;
    
    filename = g_strdup_printf ("%s/.camel_certs/%s", getenv ("HOME"), certid);
    
    if (stat (filename, &st) == -1) {
        g_free (filename);
        return FALSE;
    }
    
    g_free (filename);
    
    return st.st_uid == getuid ();
}

static int
ssl_verify (int ok, X509_STORE_CTX *ctx)
{
    CamelTcpStreamOpenSSL *stream;
    X509 *cert;
    SSL *ssl;
    int err;
    
    ssl = X509_STORE_CTX_get_ex_data (ctx, SSL_get_ex_data_X509_STORE_CTX_idx ());
    
    stream = SSL_CTX_get_app_data (ssl->ctx);
    
    cert = X509_STORE_CTX_get_current_cert (ctx);
    err = X509_STORE_CTX_get_error (ctx);
    
    if (stream)
        ok = ssl_cert_is_saved (stream->priv->expected_host);
    
    if (!ok && stream) {
        CamelService *service = stream->priv->service;
        char *prompt, *cert_str;
        char buf[257];
        
#define GET_STRING(name) X509_NAME_oneline (name, buf, 256)
        
        cert_str = g_strdup_printf (_("Issuer: %s\n"
                          "Subject: %s"),
                        GET_STRING (X509_get_issuer_name (cert)),
                        GET_STRING (X509_get_subject_name (cert)));
        
        prompt = g_strdup_printf (_("Bad certificate from %s:\n\n%s\n\n"
                        "Do you wish to accept anyway?"),
                      service->url->host, cert_str);
        
        ok = camel_session_alert_user (service->session, CAMEL_SESSION_ALERT_WARNING, prompt, TRUE);
        g_free (prompt);
        
        if (ok)
            save_ssl_cert (stream->priv->expected_host);
    }
    
    return ok;
}

static SSL *
open_ssl_connection (CamelService *service, int sockfd, CamelTcpStreamOpenSSL *openssl)
{
    SSL_CTX *ssl_ctx = NULL;
    SSL *ssl = NULL;
    int n;
    
    SSLeay_add_ssl_algorithms();
    SSL_load_error_strings();

    /* SSLv23_client_method will negotiate with SSL v2, v3, or TLS v1 */
    ssl_ctx = SSL_CTX_new (SSLv23_client_method ());
    g_return_val_if_fail (ssl_ctx != NULL, NULL);
    
    SSL_CTX_set_verify (ssl_ctx, SSL_VERIFY_PEER, &ssl_verify);
    ssl = SSL_new (ssl_ctx);
    SSL_set_fd (ssl, sockfd);

    SSL_CTX_set_app_data (ssl_ctx, openssl);

    n = SSL_connect (ssl);
    if (n != 1) {
        ssl_error_to_errno (ssl, n);

        SSL_shutdown (ssl);
        
        if (ssl->ctx)
            SSL_CTX_free (ssl->ctx);
        
        SSL_free (ssl);
        ssl = NULL;
    }
    
    return ssl;
}

static int
stream_connect (CamelTcpStream *stream, struct hostent *host, int port)
{
    CamelTcpStreamOpenSSL *openssl = CAMEL_TCP_STREAM_OPENSSL (stream);
    SSL *ssl;
    int fd;
    
    g_return_val_if_fail (host != NULL, -1);
    
    fd = socket_connect (host, port);
    if (fd == -1)
        return -1;
    
    ssl = open_ssl_connection (openssl->priv->service, fd, openssl);
    if (!ssl)
        return -1;
    
    openssl->priv->sockfd = fd;
    openssl->priv->ssl = ssl;
    
    return 0;
}


static int
get_sockopt_level (const CamelSockOptData *data)
{
    switch (data->option) {
    case CAMEL_SOCKOPT_MAXSEGMENT:
    case CAMEL_SOCKOPT_NODELAY:
        return IPPROTO_TCP;
    default:
        return SOL_SOCKET;
    }
}

static int
get_sockopt_optname (const CamelSockOptData *data)
{
    switch (data->option) {
    case CAMEL_SOCKOPT_MAXSEGMENT:
        return TCP_MAXSEG;
    case CAMEL_SOCKOPT_NODELAY:
        return TCP_NODELAY;
    case CAMEL_SOCKOPT_BROADCAST:
        return SO_BROADCAST;
    case CAMEL_SOCKOPT_KEEPALIVE:
        return SO_KEEPALIVE;
    case CAMEL_SOCKOPT_LINGER:
        return SO_LINGER;
    case CAMEL_SOCKOPT_RECVBUFFERSIZE:
        return SO_RCVBUF;
    case CAMEL_SOCKOPT_SENDBUFFERSIZE:
        return SO_SNDBUF;
    case CAMEL_SOCKOPT_REUSEADDR:
        return SO_REUSEADDR;
    case CAMEL_SOCKOPT_IPTYPEOFSERVICE:
        return SO_TYPE;
    default:
        return -1;
    }
}

static int
stream_getsockopt (CamelTcpStream *stream, CamelSockOptData *data)
{
    int optname, optlen;
    
    if ((optname = get_sockopt_optname (data)) == -1)
        return -1;
    
    if (data->option == CAMEL_SOCKOPT_NONBLOCKING) {
        int flags;
        
        flags = fcntl (((CamelTcpStreamOpenSSL *)stream)->priv->sockfd, F_GETFL);
        if (flags == -1)
            return -1;
        
        data->value.non_blocking = flags & O_NONBLOCK;
        
        return 0;
    }
    
    return getsockopt (((CamelTcpStreamOpenSSL *)stream)->priv->sockfd,
               get_sockopt_level (data),
               optname,
               (void *) &data->value,
               &optlen);
}

static int
stream_setsockopt (CamelTcpStream *stream, const CamelSockOptData *data)
{
    int optname;
    
    if ((optname = get_sockopt_optname (data)) == -1)
        return -1;
    
    if (data->option == CAMEL_SOCKOPT_NONBLOCKING) {
        int flags, set;
        
        flags = fcntl (((CamelTcpStreamOpenSSL *)stream)->priv->sockfd, F_GETFL);
        if (flags == -1)
            return -1;
        
        set = data->value.non_blocking ? 1 : 0;
        flags = (flags & ~O_NONBLOCK) | (set & O_NONBLOCK);
        
        if (fcntl (((CamelTcpStreamOpenSSL *)stream)->priv->sockfd, F_SETFL, flags) == -1)
            return -1;
        
        return 0;
    }
    
    return setsockopt (((CamelTcpStreamOpenSSL *)stream)->priv->sockfd,
               get_sockopt_level (data),
               optname,
               (void *) &data->value,
               sizeof (data->value));
}

static gpointer
stream_get_socket (CamelTcpStream *stream)
{
    return GINT_TO_POINTER (CAMEL_TCP_STREAM_OPENSSL (stream)->priv->sockfd);
}

#endif /* HAVE_OPENSSL */