Fix entropy gathering in the IMAP SSL support. From Tommi Komulainen.

diff --git a/README.SSL b/README.SSL
index 38367d80dc1ed31df3c62957e1296e5e5410a757..1cdceab4fecd5cae269291b7cfc38df12b637e75 100644 (file)
--- a/README.SSL
+++ b/README.SSL
@@ -26,6 +26,21 @@ For example:
        mailboxes {localhost:994/ssl}inbox
 
 
+If you get errors about lack of entropy, it means that Mutt was unable
+to find a source of random data to initialize SSL library with. Should
+this happen, you need to generate the data yourself and save it in a
+file somewhere Mutt will find it. Mutt tries to use files
+$SslEntropyFile, $RANDFILE (if this environment variable is set) and
+~/.rnd in that order as source for random data.
+
+If your OpenSSL is version 0.9.5 or later, you should try EGD, Entropy
+Gathering Daemon, from http://www.lothar.com/tech/crypto/ . Mutt will
+try to find EGD sockets in the following places, $SslEntropyFile,
+$EGDSOCKET (if this environment variable is set), ~/.entropy and
+/tmp/entropy. If no socket is found, static files will be tried as
+described above.
+
+
 Each time a server is contacted, its certificate is checked against
 known valid certificates. When an unknown certificate is encountered,
 you are asked to verify it. If you reject the certificate, the

diff --git a/configure.in b/configure.in
index d78e52fb9d84b3dd0e35d3d0bd952e1d846c778e..a1b929a733fb5dba2c9d71bcddc57da93a3a07b4 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -506,6 +506,9 @@ AC_ARG_WITH(ssl, [    --with-ssl[=PFX]         Compile in SSL socket support for
 
          AC_CHECK_LIB(crypto, X509_new,, AC_MSG_ERROR([Unable to find SSL library]))
          AC_CHECK_LIB(ssl, SSL_new,, AC_MSG_ERROR([Unable to find SSL library]), -lcrypto)
+
+         AC_CHECK_FUNCS(RAND_status RAND_egd)
+
          AC_DEFINE(USE_SSL)
          LIBS="$saved_LIBS"
          MUTTLIBS="$MUTTLIBS -lssl -lcrypto"

diff --git a/imap/imap_ssl.c b/imap/imap_ssl.c
index 9b73e854196e1fba2ddfe782a746b883a12faf1d..0691702d2ff422a5d7c5c2bee17bd9346a697862 100644 (file)
--- a/imap/imap_ssl.c
+++ b/imap/imap_ssl.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1999 Tommi Komulainen <Tommi.Komulainen@iki.fi>
+ * Copyright (C) 1999-2000 Tommi Komulainen <Tommi.Komulainen@iki.fi>
  * 
  *     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
@@ -18,6 +18,7 @@
 #include <openssl/ssl.h>
 #include <openssl/x509.h>
 #include <openssl/err.h>
+#include <openssl/rand.h>
 
 #undef _
 
@@ -36,7 +37,22 @@
 #define READ_X509_KEY(fp, key) PEM_read_X509(fp, key, NULL)
 #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)
+#define GOT_ENTROPY()  return 0;
+#else
+static int needentropy = 1;
+/* OpenSSL fills the entropy pool from /dev/urandom if it exists */
+#define HAVE_ENTROPY() (!access("/dev/urandom", R_OK) || !needentropy)
+#define GOT_ENTROPY()  do { needentropy = 1; return 0; } while (0)
+#endif
+
 char *SslCertFile = NULL;
+char *SslEntropyFile = NULL;
 
 typedef struct _sslsockdata
 {
@@ -46,9 +62,87 @@ typedef struct _sslsockdata
 }
 sslsockdata;
 
+/* 
+ * 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)
+ */
+int ssl_init (void)
+{
+  char path[_POSIX_PATH_MAX], *file;
+
+  if (HAVE_ENTROPY()) return 0;
+  
+  mutt_message (_("Filling entropy pool"));
+  
+  /* try egd */
+#ifdef HAVE_RAND_EGD
+  file = SslEntropyFile;
+  if (file && RAND_egd(file) != -1)
+    GOT_ENTROPY;
+  file = getenv("EGDSOCKET");
+  if (file && RAND_egd(file) != -1)
+    GOT_ENTROPY();
+  snprintf (path, sizeof(path), "%s/.entropy", NONULL(Homedir));
+  if (RAND_egd(path) != -1)
+    GOT_ENTROPY();
+  if (RAND_egd("/tmp/entropy") != -1)
+    GOT_ENTROPY();
+#endif
+
+  /* try some files */
+  file = SslEntropyFile;
+  if (!file || access(file, R_OK) == -1)
+    file = getenv("RANDFILE");
+  if (!file || access(file, R_OK) == -1) {
+    snprintf (path, sizeof(path), "%s/.rnd", NONULL(Homedir));
+    file = path;
+  }
+  if (access(file, R_OK) == 0) {
+    if (RAND_load_file(file, 10240) >= 16)
+      GOT_ENTROPY();
+  }
+
+  if (HAVE_ENTROPY()) return 0;
+
+  mutt_error (_("Failed to find enough entropy on your system"));
+  sleep (2);
+  return -1;
+}
+
+static int ssl_socket_open_err (CONNECTION *conn)
+{
+  mutt_error (_("SSL disabled due the lack of entropy"));
+  sleep (2);
+  return -1;
+}
 
 static int ssl_check_certificate (sslsockdata * data);
 
+static int ssl_socket_read (CONNECTION * conn);
+static int ssl_socket_write (CONNECTION * conn, const char *buf);
+static int ssl_socket_open (CONNECTION * conn);
+static int ssl_socket_close (CONNECTION * conn);
+
+int ssl_socket_setup (CONNECTION * conn)
+{
+  if (ssl_init() < 0) {
+    conn->open = ssl_socket_open_err;
+    return -1;
+  }
+
+  conn->open   = ssl_socket_open;
+  conn->read   = ssl_socket_read;
+  conn->write  = ssl_socket_write;
+  conn->close  = ssl_socket_close;
+
+  return 0;
+}
 
 int ssl_socket_read (CONNECTION * conn)
 {
@@ -74,7 +168,7 @@ int ssl_socket_open (CONNECTION * conn)
   data = (sslsockdata *) safe_calloc (1, sizeof (sslsockdata));
   conn->sockdata = data;
 
-  SSLeay_add_ssl_algorithms ();
+  SSL_library_init();
   data->ctx = SSL_CTX_new (SSLv23_client_method ());
 
   /* disable SSL protocols as needed */
@@ -82,7 +176,6 @@ int ssl_socket_open (CONNECTION * conn)
   {
     SSL_CTX_set_options(data->ctx, SSL_OP_NO_TLSv1);
   }
-
   if (!option(OPTSSLV2)) 
   {
     SSL_CTX_set_options(data->ctx, SSL_OP_NO_SSLv2);

diff --git a/imap/imap_ssl.h b/imap/imap_ssl.h
index 03fc785018fd5cd5c457ee87bce6dfa1b38e8b7e..2e9bed2d1bbcc7d9ec147f55e43d084ba861f098 100644 (file)
--- a/imap/imap_ssl.h
+++ b/imap/imap_ssl.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1999 Tommi Komulainen <Tommi.Komulainen@iki.fi>
+ * Copyright (C) 1999-2000 Tommi Komulainen <Tommi.Komulainen@iki.fi>
  * 
  *     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
@@ -20,10 +20,8 @@
 #define _MUTT_SSL_H_ 1
 
 extern char *SslCertFile;
+extern char *SslEntropyFile;
 
-extern int ssl_socket_read (CONNECTION *conn);
-extern int ssl_socket_write (CONNECTION *conn, const char *buf);
-extern int ssl_socket_open (CONNECTION *conn);
-extern int ssl_socket_close (CONNECTION *conn);
+extern int ssl_socket_setup (CONNECTION *conn);
 
 #endif

diff --git a/imap/socket.c b/imap/socket.c
index 533fa1fc1fe8918aee7cbadeb8274e5792255935..d8151c95b7e2bf0af5c279ada0940c1e8020be70 100644 (file)
--- a/imap/socket.c
+++ b/imap/socket.c
@@ -139,10 +139,7 @@ CONNECTION *mutt_socket_select_connection (const IMAP_MBOX *mx, int newconn)
 #ifdef USE_SSL
   if (mx->socktype == M_NEW_SSL_SOCKET) 
   {
-      conn->read = ssl_socket_read;
-      conn->write = ssl_socket_write;
-      conn->open = ssl_socket_open;
-      conn->close = ssl_socket_close;
+    ssl_socket_setup (conn);
   }
   else
 #endif

diff --git a/init.h b/init.h
index 37ed629a86d355bff556a0914fecde1558ab765f..d100aba2023f0fba894db60352430cb2bce941c0 100644 (file)
--- a/init.h
+++ b/init.h
@@ -1334,6 +1334,11 @@ struct option_t MuttVars[] = {
   ** be saved in this file and further connections are automatically 
   ** accepted.
   */
+  { "entropy_file",    DT_PATH, R_NONE, UL &SslEntropyFile, 0 },
+  /* .pp
+  ** The file which includes random data that is used to initalize SSL
+  ** library functions.
+   */
   { "ssl_use_sslv2", DT_BOOL, R_NONE, OPTSSLV2, 1 },
   /*
   ** .pp