mono/metadata/rand.c

   1 /*
   2  * rand.c: System.Security.Cryptography.RNGCryptoServiceProvider support
   3  *
   4  * Authors:
   5  *      Mark Crichton (crichton@gimp.org)
   6  *      Patrik Torstensson (p@rxc.se)
   7  *      Sebastien Pouliot (sebastien@ximian.com)
   8  *
   9  * Copyright 2001-2003 Ximian, Inc (http://www.ximian.com)
  10  * Copyright 2004-2009 Novell, Inc (http://www.novell.com)
  11  */
  12
  13 #include <config.h>
  14 #include <glib.h>
  15 #include <sys/types.h>
  16 #include <sys/stat.h>
  17 #include <fcntl.h>
  18 #ifdef HAVE_UNISTD_H
  19 #include <unistd.h>
  20 #endif
  21 #ifdef HAVE_STRING_H
  22 #include <string.h>
  23 #endif
  24
  25 #include <mono/metadata/object.h>
  26 #include <mono/metadata/rand.h>
  27 #include <mono/metadata/exception.h>
  28
  29 #if !defined(HOST_WIN32)
  30 #include <sys/socket.h>
  31 #include <sys/un.h>
  32 #include <errno.h>
  33
  34 static void
  35 get_entropy_from_server (const char *path, guchar *buf, int len)
  36 {
  37     int file;
  38     gint ret;
  39     guint offset = 0;
  40     struct sockaddr_un egd_addr;
  41
  42     file = socket (PF_UNIX, SOCK_STREAM, 0);
  43     if (file < 0)
  44         ret = -1;
  45     else {
  46         egd_addr.sun_family = AF_UNIX;
  47         strncpy (egd_addr.sun_path, path, MONO_SIZEOF_SUNPATH - 1);
  48         egd_addr.sun_path [MONO_SIZEOF_SUNPATH-1] = '\0';
  49         ret = connect (file, (struct sockaddr *)&egd_addr, sizeof(egd_addr));
  50     }
  51     if (ret == -1) {
  52         if (file >= 0)
  53             close (file);
  54         g_warning ("Entropy problem! Can't create or connect to egd socket %s", path);
  55         mono_raise_exception (mono_get_exception_execution_engine ("Failed to open egd socket"));
  56     }
  57
  58     while (len > 0) {
  59         guchar request[2];
  60         gint count = 0;
  61
  62         request [0] = 2; /* block until daemon can return enough entropy */
  63         request [1] = len < 255 ? len : 255;
  64         while (count < 2) {
  65             int sent = write (file, request + count, 2 - count);
  66             if (sent >= 0)
  67                 count += sent;
  68             else if (errno == EINTR)
  69                 continue;
  70             else {
  71                 close (file);
  72                 g_warning ("Send egd request failed %d", errno);
  73                 mono_raise_exception (mono_get_exception_execution_engine ("Failed to send request to egd socket"));
  74             }
  75         }
  76
  77         count = 0;
  78         while (count != request [1]) {
  79             int received;
  80             received = read(file, buf + offset, request [1] - count);
  81             if (received > 0) {
  82                 count += received;
  83                 offset += received;
  84             } else if (received < 0 && errno == EINTR) {
  85                 continue;
  86             } else {
  87                 close (file);
  88                 g_warning ("Receive egd request failed %d", errno);
  89                 mono_raise_exception (mono_get_exception_execution_engine ("Failed to get response from egd socket"));
  90             }
  91         }
  92
  93         len -= request [1];
  94     }
  95
  96     close (file);
  97 }
  98 #endif
  99
 100 #if defined (HOST_WIN32)
 101
 102 #include <windows.h>
 103 #include <wincrypt.h>
 104
 105 #ifndef PROV_INTEL_SEC
 106 #define PROV_INTEL_SEC          22
 107 #endif
 108 #ifndef CRYPT_VERIFY_CONTEXT
 109 #define CRYPT_VERIFY_CONTEXT    0xF0000000
 110 #endif
 111
 112 MonoBoolean
 113 ves_icall_System_Security_Cryptography_RNGCryptoServiceProvider_RngOpen (void)
 114 {
 115         /* FALSE == Local (instance) handle for randomness */
 116         return FALSE;
 117 }
 118
 119 gpointer
 120 ves_icall_System_Security_Cryptography_RNGCryptoServiceProvider_RngInitialize (MonoArray *seed)
 121 {
 122         HCRYPTPROV provider = 0;
 123
 124         /* There is no need to create a container for just random data,
 125            so we can use CRYPT_VERIFY_CONTEXT (one call) see:
 126            http://blogs.msdn.com/dangriff/archive/2003/11/19/51709.aspx */
 127
 128         /* We first try to use the Intel PIII RNG if drivers are present */
 129         if (!CryptAcquireContext (&provider, NULL, NULL, PROV_INTEL_SEC, CRYPT_VERIFY_CONTEXT)) {
 130                 /* not a PIII or no drivers available, use default RSA CSP */
 131                 if (!CryptAcquireContext (&provider, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFY_CONTEXT)) {
 132                         provider = 0;
 133                         /* exception will be thrown in managed code */
 134                 }
 135         }
 136
 137         /* seed the CSP with the supplied buffer (if present) */
 138         if ((provider != 0) && (seed)) {
 139                 guint32 len = mono_array_length (seed);
 140                 guchar *buf = mono_array_addr (seed, guchar, 0);
 141                 /* the call we replace the seed with random - this isn't what is
 142                    expected from the class library user */
 143                 guchar *data = g_malloc (len);
 144                 if (data) {
 145                         memcpy (data, buf, len);
 146                         /* add seeding material to the RNG */
 147                         CryptGenRandom (provider, len, data);
 148                         /* zeroize and free */
 149                         memset (data, 0, len);
 150                         g_free (data);
 151                 }
 152         }
 153
 154         return (gpointer) provider;
 155 }
 156
 157 gpointer
 158 ves_icall_System_Security_Cryptography_RNGCryptoServiceProvider_RngGetBytes (gpointer handle, MonoArray *arry)
 159 {
 160         HCRYPTPROV provider = (HCRYPTPROV) handle;
 161         guint32 len = mono_array_length (arry);
 162         guchar *buf = mono_array_addr (arry, guchar, 0);
 163
 164         if (!CryptGenRandom (provider, len, buf)) {
 165                 CryptReleaseContext (provider, 0);
 166                 /* we may have lost our context with CryptoAPI, but all hope isn't lost yet! */
 167                 provider = (HCRYPTPROV) ves_icall_System_Security_Cryptography_RNGCryptoServiceProvider_RngInitialize (NULL);
 168                 if (!CryptGenRandom (provider, len, buf)) {
 169                         CryptReleaseContext (provider, 0);
 170                         provider = 0;
 171                         /* exception will be thrown in managed code */
 172                 }
 173         }
 174         return (gpointer) provider;
 175 }
 176
 177 void
 178 ves_icall_System_Security_Cryptography_RNGCryptoServiceProvider_RngClose (gpointer handle)
 179 {
 180         CryptReleaseContext ((HCRYPTPROV) handle, 0);
 181 }
 182
 183 #else
 184
 185 #ifndef NAME_DEV_URANDOM
 186 #define NAME_DEV_URANDOM "/dev/urandom"
 187 #endif
 188
 189 static gboolean egd = FALSE;
 190 static gint file = -1;
 191
 192 MonoBoolean
 193 ves_icall_System_Security_Cryptography_RNGCryptoServiceProvider_RngOpen (void)
 194 {
 195         if (egd || (file >= 0))
 196                 return TRUE;
 197
 198 #if defined (NAME_DEV_URANDOM)
 199         file = open (NAME_DEV_URANDOM, O_RDONLY);
 200 #endif
 201
 202 #if defined (NAME_DEV_RANDOM)
 203         if (file < 0)
 204                 file = open (NAME_DEV_RANDOM, O_RDONLY);
 205 #endif
 206
 207         if (file < 0) {
 208                 const char *socket_path = g_getenv("MONO_EGD_SOCKET");
 209                 egd = (socket_path != NULL);
 210         }
 211
 212         /* TRUE == Global handle for randomness */
 213         return TRUE;
 214 }
 215
 216 gpointer
 217 ves_icall_System_Security_Cryptography_RNGCryptoServiceProvider_RngInitialize (MonoArray *seed)
 218 {
 219         /* if required exception will be thrown in managed code */
 220         return ((!egd && (file < 0)) ? NULL : GINT_TO_POINTER (file));
 221 }
 222
 223 gpointer
 224 ves_icall_System_Security_Cryptography_RNGCryptoServiceProvider_RngGetBytes (gpointer handle, MonoArray *arry)
 225 {
 226         gint file = GPOINTER_TO_INT (handle);
 227         guint32 len = mono_array_length (arry);
 228         guchar *buf = mono_array_addr (arry, guchar, 0);
 229
 230         if (egd) {
 231                 const char *socket_path = g_getenv ("MONO_EGD_SOCKET");
 232                 /* exception will be thrown in managed code */
 233                 if (socket_path == NULL)
 234                         return NULL;
 235                 get_entropy_from_server (socket_path, mono_array_addr (arry, guchar, 0), mono_array_length (arry));
 236                 return (gpointer) -1;
 237         } else {
 238                 /* Read until the buffer is filled. This may block if using NAME_DEV_RANDOM. */
 239                 gint count = 0;
 240                 gint err;
 241
 242                 do {
 243                         err = read (file, buf + count, len - count);
 244                         if (err < 0) {
 245                                 if (errno == EINTR)
 246                                         continue;
 247                                 break;
 248                         }
 249                         count += err;
 250                 } while (count < len);
 251
 252                 if (err < 0) {
 253                         g_warning("Entropy error! Error in read (%s).", strerror (errno));
 254                         /* exception will be thrown in managed code */
 255                         return NULL;
 256                 }
 257         }
 258
 259         /* We do not support PRNG seeding right now but the class library is this */
 260
 261         return handle;
 262 }
 263
 264 void
 265 ves_icall_System_Security_Cryptography_RNGCryptoServiceProvider_RngClose (gpointer handle)
 266 {
 267 }
 268
 269 #endif /* OS definition */