libsecurity_ssl/lib/sslRand.c

   1 /*
   2  * Copyright (c) 1999-2001,2005-2008,2010-2011 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  * sslRand.c - Randomness
  26  */
  27
  28 /* THIS FILE CONTAINS KERNEL CODE */
  29
  30 #include "sslRand.h"
  31 #include "sslDebug.h"
  32 #include <AssertMacros.h>
  33
  34 #ifdef KERNEL
  35
  36 void read_random(void* buffer, u_int numBytes);
  37
  38 #else
  39
  40 #include <TargetConditionals.h>
  41
  42 #ifdef TARGET_OS_EMBEDDED
  43 #include <Security/SecRandom.h>
  44 #else
  45 static
  46 int sslRandMacOSX(void *data, size_t len)
  47 {
  48     static int random_fd = -1;
  49
  50     if (random_fd == -1) {
  51         random_fd = open("/dev/random", O_RDONLY);
  52         if (random_fd == -1) {
  53             sslErrorLog("sslRand: error opening /dev/random: %s\n",
  54                         strerror(errno));
  55             return -1;
  56         }
  57     }
  58
  59     ssize_t bytesRead = read(random_fd, data, len);
  60     if (bytesRead != len) {
  61         sslErrorLog("sslRand: error reading %lu bytes from /dev/random: %s\n",
  62                     len, strerror(errno));
  63         serr = -1;
  64     }
  65
  66     return serr;
  67 }
  68 #endif /* TARGET_OS_EMBEDDED */
  69
  70 #endif /* KERNEL */
  71
  72 /*
  73  * Common RNG function.
  74  */
  75 int sslRand(SSLBuffer *buf)
  76 {
  77         check(buf != NULL);
  78         check(buf->data != NULL);
  79
  80         if(buf->length == 0) {
  81                 sslErrorLog("sslRand: zero buf->length\n");
  82                 return 0;
  83         }
  84
  85 #ifdef KERNEL
  86     read_random(buf->data, (u_int)buf->length);
  87     return 0;
  88 #else
  89 #ifdef TARGET_OS_EMBEDDED
  90         return SecRandomCopyBytes(kSecRandomDefault, buf->length, buf->data);
  91 #else
  92     return sslRandMacOSX(ctx, buf);
  93 #endif
  94 #endif
  95 }