X-Git-Url: http://git.madism.org/?p=apps%2Fmadmutt.git;a=blobdiff_plain;f=lib-sys%2Fmutt_ssl.c;fp=lib-sys%2Fmutt_ssl.c;h=b247377d5a60a51359d6004fd7ef43966598401e;hp=0000000000000000000000000000000000000000;hb=ccf2b75a9ed50a79c4d8e5d6235c7313fcd3719a;hpb=7b8296cfa5c33fbc73c34c4fe1ff6d7bfbaaba01

diff --git a/lib-sys/mutt_ssl.c b/lib-sys/mutt_ssl.c
new file mode 100644
index 0000000..b247377
--- /dev/null
+++ b/lib-sys/mutt_ssl.c
@@ -0,0 +1,713 @@
+/*
+ * Copyright notice from original mutt:
+ * Copyright (C) 1999-2001 Tommi Komulainen <Tommi.Komulainen@iki.fi>
+ *
+ * This file is part of mutt-ng, see http://www.muttng.org/.
+ * It's licensed under the GNU General Public License,
+ * please see the file GPL in the top level source directory.
+ */
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#ifdef USE_SSL
+
+#include <openssl/ssl.h>
+#include <openssl/x509.h>
+#include <openssl/err.h>
+#include <openssl/rand.h>
+
+#include <string.h>
+
+#include <lib-lib/mem.h>
+#include <lib-lib/str.h>
+#include <lib-lib/macros.h>
+#include <lib-lib/debug.h>
+
+#include <lib-ui/curses.h>
+#include <lib-ui/menu.h>
+
+#include "mutt.h"
+#include "mutt_socket.h"
+#include "mutt_ssl.h"
+
+
+#if OPENSSL_VERSION_NUMBER >= 0x00904000L
+#define READ_X509_KEY(fp, key)	PEM_read_X509(fp, key, NULL, NULL)
+#else
+#define READ_X509_KEY(fp, key)	PEM_read_X509(fp, key, NULL)
+#endif
+
+/* Just in case OpenSSL doesn't define DEVRANDOM */
+#ifndef DEVRANDOM
+#define DEVRANDOM "/dev/urandom"
+#endif
+
+/* This is ugly, but as RAND_status came in on OpenSSL version 0.9.5
+ * and the code has to support older versions too, this is seemed to
+ * be cleaner way compared to having even uglier #ifdefs all around.
+ */
+#ifdef HAVE_RAND_STATUS
+#define HAVE_ENTROPY()	(RAND_status() == 1)
+#else
+static int entropy_byte_count = 0;
+
+/* OpenSSL fills the entropy pool from /dev/urandom if it exists */
+#define HAVE_ENTROPY()	(!access(DEVRANDOM, R_OK) || entropy_byte_count >= 16)
+#endif
+
+typedef struct _sslsockdata {
+  SSL_CTX *ctx;
+  SSL *ssl;
+  X509 *cert;
+} sslsockdata;
+
+/* local prototypes */
+static int ssl_init (void);
+static int add_entropy (const char *file);
+static int ssl_socket_read (CONNECTION * conn, char *buf, size_t len);
+static int ssl_socket_write (CONNECTION * conn, const char *buf, size_t len);
+static int ssl_socket_open (CONNECTION * conn);
+static int ssl_socket_close (CONNECTION * conn);
+static int tls_close (CONNECTION * conn);
+static int ssl_check_certificate (sslsockdata * data);
+static void ssl_get_client_cert (sslsockdata * ssldata, CONNECTION * conn);
+static int ssl_passwd_cb (char *buf, int size, int rwflag, void *userdata);
+static int ssl_negotiate (sslsockdata *);
+
+/* mutt_ssl_starttls: Negotiate TLS over an already opened connection.
+ *   TODO: Merge this code better with ssl_socket_open. */
+int mutt_ssl_starttls (CONNECTION * conn)
+{
+  sslsockdata *ssldata;
+  int maxbits;
+
+  if (ssl_init ())
+    goto bail;
+
+  ssldata = p_new(sslsockdata, 1);
+  /* the ssl_use_xxx protocol options don't apply. We must use TLS in TLS. */
+  if (!(ssldata->ctx = SSL_CTX_new (TLSv1_client_method ()))) {
+    debug_print (1, ("Error allocating SSL_CTX\n"));
+    goto bail_ssldata;
+  }
+
+  ssl_get_client_cert (ssldata, conn);
+
+  if (!(ssldata->ssl = SSL_new (ssldata->ctx))) {
+    debug_print (1, ("Error allocating SSL\n"));
+    goto bail_ctx;
+  }
+
+  if (SSL_set_fd (ssldata->ssl, conn->fd) != 1) {
+    debug_print (1, ("Error setting fd\n"));
+    goto bail_ssl;
+  }
+
+  if (ssl_negotiate (ssldata))
+    goto bail_ssl;
+
+  /* hmm. watch out if we're starting TLS over any method other than raw. */
+  conn->sockdata = ssldata;
+  conn->conn_read = ssl_socket_read;
+  conn->conn_write = ssl_socket_write;
+  conn->conn_close = tls_close;
+
+  conn->ssf = SSL_CIPHER_get_bits (SSL_get_current_cipher (ssldata->ssl),
+                                   &maxbits);
+
+  return 0;
+
+bail_ssl:
+  p_delete(&ssldata->ssl);
+bail_ctx:
+  p_delete(&ssldata->ctx);
+bail_ssldata:
+  p_delete(&ssldata);
+bail:
+  return -1;
+}
+
+/* 
+ * OpenSSL library needs to be fed with sufficient entropy. On systems
+ * with /dev/urandom, this is done transparently by the library itself,
+ * on other systems we need to fill the entropy pool ourselves.
+ *
+ * Even though only OpenSSL 0.9.5 and later will complain about the
+ * lack of entropy, we try to our best and fill the pool with older
+ * versions also. (That's the reason for the ugly #ifdefs and macros,
+ * otherwise I could have simply #ifdef'd the whole ssl_init funcion)
+ */
+static int ssl_init (void)
+{
+  char path[_POSIX_PATH_MAX];
+  static unsigned char init_complete = 0;
+
+  if (init_complete)
+    return 0;
+
+  if (!HAVE_ENTROPY ()) {
+    /* load entropy from files */
+    add_entropy (SslEntropyFile);
+    add_entropy (RAND_file_name (path, sizeof (path)));
+
+    /* load entropy from egd sockets */
+#ifdef HAVE_RAND_EGD
+    add_entropy (getenv ("EGDSOCKET"));
+    snprintf (path, sizeof (path), "%s/.entropy", NONULL (Homedir));
+    add_entropy (path);
+    add_entropy ("/tmp/entropy");
+#endif
+
+    /* shuffle $RANDFILE (or ~/.rnd if unset) */
+    RAND_write_file (RAND_file_name (path, sizeof (path)));
+    mutt_clear_error ();
+    if (!HAVE_ENTROPY ()) {
+      mutt_error (_("Failed to find enough entropy on your system"));
+      mutt_sleep (2);
+      return -1;
+    }
+  }
+
+  /* I don't think you can do this just before reading the error. The call
+   * itself might clobber the last SSL error. */
+  SSL_load_error_strings ();
+  SSL_library_init ();
+  init_complete = 1;
+  return 0;
+}
+
+static int add_entropy (const char *file)
+{
+  struct stat st;
+  int n = -1;
+
+  if (!file)
+    return 0;
+
+  if (stat (file, &st) == -1)
+    return errno == ENOENT ? 0 : -1;
+
+  mutt_message (_("Filling entropy pool: %s...\n"), file);
+
+  /* check that the file permissions are secure */
+  if (st.st_uid != getuid () ||
+      ((st.st_mode & (S_IWGRP | S_IRGRP)) != 0) ||
+      ((st.st_mode & (S_IWOTH | S_IROTH)) != 0)) {
+    mutt_error (_("%s has insecure permissions!"), file);
+    mutt_sleep (2);
+    return -1;
+  }
+
+#ifdef HAVE_RAND_EGD
+  n = RAND_egd (file);
+#endif
+  if (n <= 0)
+    n = RAND_load_file (file, -1);
+
+#ifndef HAVE_RAND_STATUS
+  if (n > 0)
+    entropy_byte_count += n;
+#endif
+  return n;
+}
+
+static int ssl_socket_open_err (CONNECTION * conn)
+{
+  mutt_error (_("SSL disabled due the lack of entropy"));
+  mutt_sleep (2);
+  return -1;
+}
+
+
+int mutt_ssl_socket_setup (CONNECTION * conn)
+{
+  if (ssl_init () < 0) {
+    conn->conn_open = ssl_socket_open_err;
+    return -1;
+  }
+
+  conn->conn_open = ssl_socket_open;
+  conn->conn_read = ssl_socket_read;
+  conn->conn_write = ssl_socket_write;
+  conn->conn_close = ssl_socket_close;
+
+  return 0;
+}
+
+static int ssl_socket_read (CONNECTION * conn, char *buf, size_t len)
+{
+  sslsockdata *data = conn->sockdata;
+
+  return SSL_read (data->ssl, buf, len);
+}
+
+static int ssl_socket_write (CONNECTION * conn, const char *buf, size_t len)
+{
+  sslsockdata *data = conn->sockdata;
+
+  return SSL_write (data->ssl, buf, len);
+}
+
+static int ssl_socket_open (CONNECTION * conn)
+{
+  sslsockdata *data;
+  int maxbits;
+
+  if (raw_socket_open (conn) < 0)
+    return -1;
+
+  data = p_new(sslsockdata, 1);
+  conn->sockdata = data;
+
+  data->ctx = SSL_CTX_new (SSLv23_client_method ());
+
+  /* disable SSL protocols as needed */
+  if (!option (OPTTLSV1)) {
+    SSL_CTX_set_options (data->ctx, SSL_OP_NO_TLSv1);
+  }
+  if (!option (OPTSSLV2)) {
+    SSL_CTX_set_options (data->ctx, SSL_OP_NO_SSLv2);
+  }
+  if (!option (OPTSSLV3)) {
+    SSL_CTX_set_options (data->ctx, SSL_OP_NO_SSLv3);
+  }
+
+  ssl_get_client_cert (data, conn);
+
+  data->ssl = SSL_new (data->ctx);
+  SSL_set_fd (data->ssl, conn->fd);
+
+  if (ssl_negotiate (data)) {
+    mutt_socket_close (conn);
+    return -1;
+  }
+
+  conn->ssf = SSL_CIPHER_get_bits (SSL_get_current_cipher (data->ssl),
+                                   &maxbits);
+
+  return 0;
+}
+
+/* ssl_negotiate: After SSL state has been initialised, attempt to negotiate
+ *   SSL over the wire, including certificate checks. */
+static int ssl_negotiate (sslsockdata * ssldata)
+{
+  int err;
+  const char *errmsg;
+
+#if OPENSSL_VERSION_NUMBER >= 0x00906000L
+  /* This only exists in 0.9.6 and above. Without it we may get interrupted
+   *   reads or writes. Bummer. */
+  SSL_set_mode (ssldata->ssl, SSL_MODE_AUTO_RETRY);
+#endif
+
+  if ((err = SSL_connect (ssldata->ssl)) != 1) {
+    switch (SSL_get_error (ssldata->ssl, err)) {
+    case SSL_ERROR_SYSCALL:
+      errmsg = _("I/O error");
+      break;
+    case SSL_ERROR_SSL:
+      errmsg = ERR_error_string (ERR_get_error (), NULL);
+      break;
+    default:
+      errmsg = _("unknown error");
+    }
+
+    mutt_error (_("SSL failed: %s"), errmsg);
+    mutt_sleep (1);
+
+    return -1;
+  }
+
+  ssldata->cert = SSL_get_peer_certificate (ssldata->ssl);
+  if (!ssldata->cert) {
+    mutt_error (_("Unable to get certificate from peer"));
+    mutt_sleep (1);
+    return -1;
+  }
+
+  if (!ssl_check_certificate (ssldata))
+    return -1;
+
+  mutt_message (_("SSL connection using %s (%s)"),
+                SSL_get_cipher_version (ssldata->ssl),
+                SSL_get_cipher_name (ssldata->ssl));
+  mutt_sleep (0);
+
+  return 0;
+}
+
+static int ssl_socket_close (CONNECTION * conn)
+{
+  sslsockdata *data = conn->sockdata;
+
+  if (data) {
+    SSL_shutdown (data->ssl);
+#if 0
+    X509_free (data->cert);
+#endif
+    SSL_free (data->ssl);
+    SSL_CTX_free (data->ctx);
+    p_delete(&conn->sockdata);
+  }
+
+  return raw_socket_close (conn);
+}
+
+static int compare_certificates (X509 *cert, X509 *peercert, 
+                                 unsigned char *peermd,
+                                 unsigned int peermdlen) {
+  unsigned char md[EVP_MAX_MD_SIZE];
+  unsigned int mdlen;
+
+  /* Avoid CPU-intensive digest calculation if the certificates are
+  * not even remotely equal.
+  */
+  if (X509_subject_name_cmp (cert, peercert) != 0 || 
+      X509_issuer_name_cmp (cert, peercert) != 0)
+    return -1;
+
+  if (!X509_digest (cert, EVP_sha1(), md, &mdlen) || peermdlen != mdlen)
+    return -1;
+
+  if (memcmp(peermd, md, mdlen) != 0)
+    return -1;
+
+  return 0;
+}
+
+static int check_certificate_cache (X509 *peercert) {
+  unsigned char peermd[EVP_MAX_MD_SIZE];
+  unsigned int peermdlen;
+  X509 *cert;
+  LIST *scert;
+
+  if (!X509_digest (peercert, EVP_sha1(), peermd, &peermdlen)) 
+    return 0;
+
+  for (scert = SslSessionCerts; scert; scert = scert->next) {
+    cert = *(X509**)scert->data;
+    if (!compare_certificates (cert, peercert, peermd, peermdlen)) {
+      return 1;
+    }
+  }
+ return 0;
+}
+
+static int tls_close (CONNECTION * conn)
+{
+  int rc;
+
+  rc = ssl_socket_close (conn);
+  conn->conn_read = raw_socket_read;
+  conn->conn_write = raw_socket_write;
+  conn->conn_close = raw_socket_close;
+
+  return rc;
+}
+
+static char *x509_get_part (char *line, const char *ndx)
+{
+  static char ret[SHORT_STRING];
+  char *c, *c2;
+
+  m_strcpy(ret, sizeof(ret), _("Unknown"));
+
+  c = strstr (line, ndx);
+  if (c) {
+    c += m_strlen(ndx);
+    c2 = strchr (c, '/');
+    if (c2)
+      *c2 = '\0';
+    m_strcpy(ret, sizeof(ret), c);
+    if (c2)
+      *c2 = '/';
+  }
+
+  return ret;
+}
+
+static void x509_fingerprint (char *s, int l, X509 * cert)
+{
+  unsigned char md[EVP_MAX_MD_SIZE];
+  unsigned int n;
+  int j;
+
+  if (!X509_digest (cert, EVP_md5 (), md, &n)) {
+    m_strcpy(s, l, _("[unable to calculate]"));
+  }
+  else {
+    for (j = 0; j < (int) n; j++) {
+      char ch[8];
+
+      snprintf(ch, 8, "%02X%s", md[j], (j % 2 ? " " : ""));
+      m_strcat(s, l, ch);
+    }
+  }
+}
+
+static char *asn1time_to_string (ASN1_UTCTIME * tm)
+{
+  static char buf[64];
+  BIO *bio;
+
+  m_strcpy(buf, sizeof(buf), _("[invalid date]"));
+
+  bio = BIO_new (BIO_s_mem ());
+  if (bio) {
+    if (ASN1_TIME_print (bio, tm))
+      (void) BIO_read (bio, buf, sizeof (buf));
+    BIO_free (bio);
+  }
+
+  return buf;
+}
+
+static int check_certificate_by_signer (X509 * peercert)
+{
+  X509_STORE_CTX xsc;
+  X509_STORE *ctx;
+  int pass = 0;
+
+  ctx = X509_STORE_new ();
+  if (ctx == NULL)
+    return 0;
+
+  if (option (OPTSSLSYSTEMCERTS)) {
+    if (X509_STORE_set_default_paths (ctx))
+      pass++;
+    else
+      debug_print (2, ("X509_STORE_set_default_paths failed\n"));
+  }
+
+  if (X509_STORE_load_locations (ctx, SslCertFile, NULL))
+    pass++;
+  else
+    debug_print (2, ("X509_STORE_load_locations_failed\n"));
+
+  if (pass == 0) {
+    /* nothing to do */
+    X509_STORE_free (ctx);
+    return 0;
+  }
+
+  X509_STORE_CTX_init (&xsc, ctx, peercert, NULL);
+
+  pass = (X509_verify_cert (&xsc) > 0);
+#ifdef DEBUG
+  if (!pass) {
+    char buf[SHORT_STRING];
+    int err;
+
+    err = X509_STORE_CTX_get_error (&xsc);
+    snprintf (buf, sizeof (buf), "%s (%d)",
+              X509_verify_cert_error_string (err), err);
+    debug_print (2, ("X509_verify_cert: %s\n", buf));
+  }
+#endif
+  X509_STORE_CTX_cleanup (&xsc);
+  X509_STORE_free (ctx);
+
+  return pass;
+}
+
+static int check_certificate_by_digest (X509 * peercert)
+{
+  unsigned char peermd[EVP_MAX_MD_SIZE];
+  unsigned int peermdlen;
+  X509 *cert = NULL;
+  int pass = 0;
+  FILE *fp;
+
+  /* expiration check */
+  if (X509_cmp_current_time (X509_get_notBefore (peercert)) >= 0) {
+    debug_print (2, ("Server certificate is not yet valid\n"));
+    mutt_error (_("Server certificate is not yet valid"));
+    mutt_sleep (2);
+    return 0;
+  }
+  if (X509_cmp_current_time (X509_get_notAfter (peercert)) <= 0) {
+    debug_print (2, ("Server certificate has expired\n"));
+    mutt_error (_("Server certificate has expired"));
+    mutt_sleep (2);
+    return 0;
+  }
+
+  if ((fp = fopen (SslCertFile, "rt")) == NULL)
+    return 0;
+
+  if (!X509_digest (peercert, EVP_sha1 (), peermd, &peermdlen)) {
+    fclose (fp);
+    return 0;
+  }
+
+  while ((cert = READ_X509_KEY (fp, &cert)) != NULL) {
+    pass = compare_certificates (cert, peercert, peermd, peermdlen) ? 0 : 1;
+    if (pass)
+      break;
+  }
+  X509_free (cert);
+  fclose (fp);
+
+  return pass;
+}
+
+static int ssl_check_certificate (sslsockdata * data)
+{
+  char *part[] = { "/CN=", "/Email=", "/O=", "/OU=", "/L=", "/ST=", "/C=" };
+  char helpstr[SHORT_STRING];
+  char buf[SHORT_STRING];
+  MUTTMENU *menu;
+  int done, row, i;
+  FILE *fp;
+  char *name = NULL, *c;
+
+  /* check session cache first */
+  if (check_certificate_cache (data->cert)) {
+    debug_print (1, ("ssl_check_certificate: using cached certificate\n"));
+    return 1;
+  }
+
+  if (check_certificate_by_signer (data->cert)) {
+    debug_print (1, ("signer check passed\n"));
+    return 1;
+  }
+
+  /* automatic check from user's database */
+  if (SslCertFile && check_certificate_by_digest (data->cert)) {
+    debug_print (1, ("digest check passed\n"));
+    return 1;
+  }
+
+  /* interactive check from user */
+  menu = mutt_new_menu ();
+  menu->max = 19;
+  menu->dialog = p_new(char *, menu->max);
+  for (i = 0; i < menu->max; i++)
+    menu->dialog[i] = p_new(char, SHORT_STRING);
+
+  row = 0;
+  m_strcpy(menu->dialog[row], SHORT_STRING,
+           _("This certificate belongs to:"));
+  row++;
+  name = X509_NAME_oneline (X509_get_subject_name (data->cert),
+                            buf, sizeof (buf));
+  for (i = 0; i < 5; i++) {
+    c = x509_get_part (name, part[i]);
+    snprintf (menu->dialog[row++], SHORT_STRING, "   %s", c);
+  }
+
+  row++;
+  m_strcpy(menu->dialog[row], SHORT_STRING,
+           _("This certificate was issued by:"));
+  row++;
+  name = X509_NAME_oneline (X509_get_issuer_name (data->cert),
+                            buf, sizeof (buf));
+  for (i = 0; i < 5; i++) {
+    c = x509_get_part (name, part[i]);
+    snprintf (menu->dialog[row++], SHORT_STRING, "   %s", c);
+  }
+
+  row++;
+  snprintf (menu->dialog[row++], SHORT_STRING, "%s",
+            _("This certificate is valid"));
+  snprintf (menu->dialog[row++], SHORT_STRING, _("   from %s"),
+            asn1time_to_string (X509_get_notBefore (data->cert)));
+  snprintf (menu->dialog[row++], SHORT_STRING, _("     to %s"),
+            asn1time_to_string (X509_get_notAfter (data->cert)));
+
+  row++;
+  buf[0] = '\0';
+  x509_fingerprint (buf, sizeof (buf), data->cert);
+  snprintf (menu->dialog[row++], SHORT_STRING, _("Fingerprint: %s"), buf);
+
+  menu->title = _("SSL Certificate check");
+
+  if (SslCertFile && X509_cmp_current_time (X509_get_notAfter (data->cert)) >= 0
+      && X509_cmp_current_time (X509_get_notBefore (data->cert)) < 0) {
+    menu->prompt = _("(r)eject, accept (o)nce, (a)ccept always");
+    menu->keys = _("roa");
+  }
+  else {
+    menu->prompt = _("(r)eject, accept (o)nce");
+    menu->keys = _("ro");
+  }
+
+  helpstr[0] = '\0';
+  mutt_make_help (buf, sizeof (buf), _("Exit  "), MENU_GENERIC, OP_EXIT);
+  m_strcat(helpstr, sizeof(helpstr), buf);
+  mutt_make_help (buf, sizeof (buf), _("Help"), MENU_GENERIC, OP_HELP);
+  m_strcat(helpstr, sizeof(helpstr), buf);
+  menu->help = helpstr;
+
+  done = 0;
+  set_option (OPTUNBUFFEREDINPUT);
+  while (!done) {
+    switch (mutt_menuLoop (menu)) {
+    case -1:                   /* abort */
+    case OP_MAX + 1:           /* reject */
+    case OP_EXIT:
+      done = 1;
+      break;
+    case OP_MAX + 3:           /* accept always */
+      done = 0;
+      if ((fp = fopen (SslCertFile, "a"))) {
+        if (PEM_write_X509 (fp, data->cert))
+          done = 1;
+        fclose (fp);
+      }
+      if (!done) {
+        mutt_error (_("Warning: Couldn't save certificate"));
+        mutt_sleep (2);
+      }
+      else {
+        mutt_message (_("Certificate saved"));
+        mutt_sleep (0);
+      }
+      /* fall through */
+    case OP_MAX + 2:           /* accept once */
+      done = 2;
+      /* keep a handle on accepted certificates in case we want to
+       * open up another connection to the same server in this session */
+      SslSessionCerts = mutt_add_list_n (SslSessionCerts, &data->cert,
+                                         sizeof (X509 **));
+      break;
+    }
+  }
+  unset_option (OPTUNBUFFEREDINPUT);
+  mutt_menuDestroy (&menu);
+  return (done == 2);
+}
+
+static void ssl_get_client_cert (sslsockdata * ssldata, CONNECTION * conn)
+{
+  if (SslClientCert) {
+    debug_print (2, ("Using client certificate %s\n", SslClientCert));
+    SSL_CTX_set_default_passwd_cb_userdata (ssldata->ctx, &conn->account);
+    SSL_CTX_set_default_passwd_cb (ssldata->ctx, ssl_passwd_cb);
+    SSL_CTX_use_certificate_file (ssldata->ctx, SslClientCert,
+                                  SSL_FILETYPE_PEM);
+    SSL_CTX_use_PrivateKey_file (ssldata->ctx, SslClientCert,
+                                 SSL_FILETYPE_PEM);
+  }
+}
+
+static int ssl_passwd_cb (char *buf, int size, int rwflag, void *userdata)
+{
+  ACCOUNT *account = (ACCOUNT *) userdata;
+
+  if (mutt_account_getuser (account))
+    return 0;
+
+  debug_print (2, ("getting password for %s@%s:%u\n",
+              account->user, account->host, account->port));
+
+  if (mutt_account_getpass (account))
+    return 0;
+
+  return snprintf (buf, size, "%s", account->pass);
+}
+
+#endif /* USE_SSL */