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rand_egd.c
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1 /* crypto/rand/rand_egd.c */
2 /* Written by Ulf Moeller and Lutz Jaenicke for the OpenSSL project. */
3 /* ====================================================================
4  * Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
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34  * "This product includes software developed by the OpenSSL Project
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51  * This product includes cryptographic software written by Eric Young
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53  * Hudson ([email protected]).
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55  */
56 
57 #include <openssl/e_os2.h>
58 #include <openssl/rand.h>
59 #include <openssl/buffer.h>
60 
61 /*
62  * Query the EGD <URL: http://www.lothar.com/tech/crypto/>.
63  *
64  * This module supplies three routines:
65  *
66  * RAND_query_egd_bytes(path, buf, bytes)
67  * will actually query "bytes" bytes of entropy form the egd-socket located
68  * at path and will write them to buf (if supplied) or will directly feed
69  * it to RAND_seed() if buf==NULL.
70  * The number of bytes is not limited by the maximum chunk size of EGD,
71  * which is 255 bytes. If more than 255 bytes are wanted, several chunks
72  * of entropy bytes are requested. The connection is left open until the
73  * query is competed.
74  * RAND_query_egd_bytes() returns with
75  * -1 if an error occured during connection or communication.
76  * num the number of bytes read from the EGD socket. This number is either
77  * the number of bytes requested or smaller, if the EGD pool is
78  * drained and the daemon signals that the pool is empty.
79  * This routine does not touch any RAND_status(). This is necessary, since
80  * PRNG functions may call it during initialization.
81  *
82  * RAND_egd_bytes(path, bytes) will query "bytes" bytes and have them
83  * used to seed the PRNG.
84  * RAND_egd_bytes() is a wrapper for RAND_query_egd_bytes() with buf=NULL.
85  * Unlike RAND_query_egd_bytes(), RAND_status() is used to test the
86  * seed status so that the return value can reflect the seed state:
87  * -1 if an error occured during connection or communication _or_
88  * if the PRNG has still not received the required seeding.
89  * num the number of bytes read from the EGD socket. This number is either
90  * the number of bytes requested or smaller, if the EGD pool is
91  * drained and the daemon signals that the pool is empty.
92  *
93  * RAND_egd(path) will query 255 bytes and use the bytes retreived to seed
94  * the PRNG.
95  * RAND_egd() is a wrapper for RAND_egd_bytes() with numbytes=255.
96  */
97 
98 #if defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VMS) || defined(OPENSSL_SYS_MSDOS) || defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_NETWARE) || defined(OPENSSL_SYS_VOS) || defined(OPENSSL_SYS_BEOS)
99 int RAND_query_egd_bytes(const char *path, unsigned char *buf, int bytes)
100  {
101  return(-1);
102  }
103 int RAND_egd(const char *path)
104  {
105  return(-1);
106  }
107 
108 int RAND_egd_bytes(const char *path,int bytes)
109  {
110  return(-1);
111  }
112 #else
113 #include <openssl/opensslconf.h>
114 #include OPENSSL_UNISTD
115 #include <sys/types.h>
116 #include <sys/socket.h>
117 #ifndef NO_SYS_UN_H
118 # ifdef OPENSSL_SYS_VXWORKS
119 # include <streams/un.h>
120 # else
121 # include <sys/un.h>
122 # endif
123 #else
124 struct sockaddr_un {
125  short sun_family; /* AF_UNIX */
126  char sun_path[108]; /* path name (gag) */
127 };
128 #endif /* NO_SYS_UN_H */
129 #include <string.h>
130 #include <errno.h>
131 
132 #ifndef offsetof
133 # define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
134 #endif
135 
136 int RAND_query_egd_bytes(const char *path, unsigned char *buf, int bytes)
137  {
138  int ret = 0;
139  struct sockaddr_un addr;
140  int len, num, numbytes;
141  int fd = -1;
142  int success;
143  unsigned char egdbuf[2], tempbuf[255], *retrievebuf;
144 
145  memset(&addr, 0, sizeof(addr));
146  addr.sun_family = AF_UNIX;
147  if (strlen(path) >= sizeof(addr.sun_path))
148  return (-1);
149  BUF_strlcpy(addr.sun_path,path,sizeof addr.sun_path);
150  len = offsetof(struct sockaddr_un, sun_path) + strlen(path);
151  fd = socket(AF_UNIX, SOCK_STREAM, 0);
152  if (fd == -1) return (-1);
153  success = 0;
154  while (!success)
155  {
156  if (connect(fd, (struct sockaddr *)&addr, len) == 0)
157  success = 1;
158  else
159  {
160  switch (errno)
161  {
162 #ifdef EINTR
163  case EINTR:
164 #endif
165 #ifdef EAGAIN
166  case EAGAIN:
167 #endif
168 #ifdef EINPROGRESS
169  case EINPROGRESS:
170 #endif
171 #ifdef EALREADY
172  case EALREADY:
173 #endif
174  /* No error, try again */
175  break;
176 #ifdef EISCONN
177  case EISCONN:
178  success = 1;
179  break;
180 #endif
181  default:
182  goto err; /* failure */
183  }
184  }
185  }
186 
187  while(bytes > 0)
188  {
189  egdbuf[0] = 1;
190  egdbuf[1] = bytes < 255 ? bytes : 255;
191  numbytes = 0;
192  while (numbytes != 2)
193  {
194  num = write(fd, egdbuf + numbytes, 2 - numbytes);
195  if (num >= 0)
196  numbytes += num;
197  else
198  {
199  switch (errno)
200  {
201 #ifdef EINTR
202  case EINTR:
203 #endif
204 #ifdef EAGAIN
205  case EAGAIN:
206 #endif
207  /* No error, try again */
208  break;
209  default:
210  ret = -1;
211  goto err; /* failure */
212  }
213  }
214  }
215  numbytes = 0;
216  while (numbytes != 1)
217  {
218  num = read(fd, egdbuf, 1);
219  if (num == 0)
220  goto err; /* descriptor closed */
221  else if (num > 0)
222  numbytes += num;
223  else
224  {
225  switch (errno)
226  {
227 #ifdef EINTR
228  case EINTR:
229 #endif
230 #ifdef EAGAIN
231  case EAGAIN:
232 #endif
233  /* No error, try again */
234  break;
235  default:
236  ret = -1;
237  goto err; /* failure */
238  }
239  }
240  }
241  if(egdbuf[0] == 0)
242  goto err;
243  if (buf)
244  retrievebuf = buf + ret;
245  else
246  retrievebuf = tempbuf;
247  numbytes = 0;
248  while (numbytes != egdbuf[0])
249  {
250  num = read(fd, retrievebuf + numbytes, egdbuf[0] - numbytes);
251  if (num == 0)
252  goto err; /* descriptor closed */
253  else if (num > 0)
254  numbytes += num;
255  else
256  {
257  switch (errno)
258  {
259 #ifdef EINTR
260  case EINTR:
261 #endif
262 #ifdef EAGAIN
263  case EAGAIN:
264 #endif
265  /* No error, try again */
266  break;
267  default:
268  ret = -1;
269  goto err; /* failure */
270  }
271  }
272  }
273  ret += egdbuf[0];
274  bytes -= egdbuf[0];
275  if (!buf)
276  RAND_seed(tempbuf, egdbuf[0]);
277  }
278  err:
279  if (fd != -1) close(fd);
280  return(ret);
281  }
282 
283 
284 int RAND_egd_bytes(const char *path, int bytes)
285  {
286  int num, ret = 0;
287 
288  num = RAND_query_egd_bytes(path, NULL, bytes);
289  if (num < 1) goto err;
290  if (RAND_status() == 1)
291  ret = num;
292  err:
293  return(ret);
294  }
295 
296 
297 int RAND_egd(const char *path)
298  {
299  return (RAND_egd_bytes(path, 255));
300  }
301 
302 
303 #endif
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