1 files changed, 403 insertions, 236 deletions

diff --git a/src/lib/libcrypto/rand/md_rand.c b/src/lib/libcrypto/rand/md_rand.c
index f44b36a8b9..a00ed70718 100644
--- a/src/lib/libcrypto/rand/md_rand.c
+++ b/src/lib/libcrypto/rand/md_rand.c
@@ -55,100 +55,185 @@
  * copied and put under another distribution licence
  * [including the GNU Public Licence.]
  */
+/* ====================================================================
+ * Copyright (c) 1998-2001 The OpenSSL Project.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer. 
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ *    software must display the following acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com).  This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com).
+ *
+ */
 
-#include <stdio.h>
-#include "cryptlib.h"
-#include <sys/types.h>
-#include <time.h>
-
-#if !defined(USE_MD5_RAND) && !defined(USE_SHA1_RAND) && !defined(USE_MDC2_RAND) && !defined(USE_MD2_RAND)
-#ifndef NO_MD5
-#define USE_MD5_RAND
-#elif !defined(NO_SHA1)
-#define USE_SHA1_RAND
-#elif !defined(NO_MDC2)
-#define USE_MDC2_RAND
-#elif !defined(NO_MD2)
-#define USE_MD2_RAND
-#else
-We need a message digest of some type 
-#endif
+#ifdef MD_RAND_DEBUG
+# ifndef NDEBUG
+#   define NDEBUG
+# endif
 #endif
 
-/* Changed how the state buffer used.  I now attempt to 'wrap' such
- * that I don't run over the same locations the next time  go through
- * the 1023 bytes - many thanks to
- * Robert J. LeBlanc <rjl@renaissoft.com> for his comments
- */
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
 
-#if defined(USE_MD5_RAND)
-#include "md5.h"
-#define MD_DIGEST_LENGTH        MD5_DIGEST_LENGTH
-#define MD_CTX                  MD5_CTX
-#define MD_Init(a)              MD5_Init(a)
-#define MD_Update(a,b,c)        MD5_Update(a,b,c)
-#define MD_Final(a,b)           MD5_Final(a,b)
-#elif defined(USE_SHA1_RAND)
-#include "sha.h"
-#define MD_DIGEST_LENGTH        SHA_DIGEST_LENGTH
-#define MD_CTX                  SHA_CTX
-#define MD_Init(a)              SHA1_Init(a)
-#define MD_Update(a,b,c)        SHA1_Update(a,b,c)
-#define MD_Final(a,b)           SHA1_Final(a,b)
-#elif defined(USE_MDC2_RAND)
-#include "mdc2.h"
-#define MD_DIGEST_LENGTH        MDC2_DIGEST_LENGTH
-#define MD_CTX                  MDC2_CTX
-#define MD_Init(a)              MDC2_Init(a)
-#define MD_Update(a,b,c)        MDC2_Update(a,b,c)
-#define MD_Final(a,b)           MDC2_Final(a,b)
-#elif defined(USE_MD2_RAND)
-#include "md2.h"
-#define MD_DIGEST_LENGTH        MD2_DIGEST_LENGTH
-#define MD_CTX                  MD2_CTX
-#define MD_Init(a)              MD2_Init(a)
-#define MD_Update(a,b,c)        MD2_Update(a,b,c)
-#define MD_Final(a,b)           MD2_Final(a,b)
-#endif
+#include "e_os.h"
 
-#include "rand.h"
+#include <openssl/rand.h>
+#include "rand_lcl.h"
 
-/*#define NORAND        1 */
-/*#define PREDICT       1 */
+#include <openssl/crypto.h>
+#include <openssl/err.h>
+
+#ifdef BN_DEBUG
+# define PREDICT
+#endif
+
+/* #define PREDICT      1 */
 
 #define STATE_SIZE      1023
 static int state_num=0,state_index=0;
 static unsigned char state[STATE_SIZE+MD_DIGEST_LENGTH];
 static unsigned char md[MD_DIGEST_LENGTH];
-static int md_count=0;
+static long md_count[2]={0,0};
+static double entropy=0;
+static int initialized=0;
 
-char *RAND_version="RAND part of SSLeay 0.9.0b 29-Jun-1998";
+static unsigned int crypto_lock_rand = 0; /* may be set only when a thread
+                                           * holds CRYPTO_LOCK_RAND
+                                           * (to prevent double locking) */
+/* access to lockin_thread is synchronized by CRYPTO_LOCK_RAND2 */
+static unsigned long locking_thread = 0; /* valid iff crypto_lock_rand is set */
 
-void RAND_cleanup()
+
+#ifdef PREDICT
+int rand_predictable=0;
+#endif
+
+const char *RAND_version="RAND" OPENSSL_VERSION_PTEXT;
+
+static void ssleay_rand_cleanup(void);
+static void ssleay_rand_seed(const void *buf, int num);
+static void ssleay_rand_add(const void *buf, int num, double add_entropy);
+static int ssleay_rand_bytes(unsigned char *buf, int num);
+static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num);
+static int ssleay_rand_status(void);
+
+RAND_METHOD rand_ssleay_meth={
+        ssleay_rand_seed,
+        ssleay_rand_bytes,
+        ssleay_rand_cleanup,
+        ssleay_rand_add,
+        ssleay_rand_pseudo_bytes,
+        ssleay_rand_status
+        }; 
+
+RAND_METHOD *RAND_SSLeay(void)
+        {
+        return(&rand_ssleay_meth);
+        }
+
+static void ssleay_rand_cleanup(void)
         {
         memset(state,0,sizeof(state));
         state_num=0;
         state_index=0;
         memset(md,0,MD_DIGEST_LENGTH);
-        md_count=0;
+        md_count[0]=0;
+        md_count[1]=0;
+        entropy=0;
+        initialized=0;
         }
 
-void RAND_seed(buf,num)
-unsigned char *buf;
-int num;
+static void ssleay_rand_add(const void *buf, int num, double add)
         {
-        int i,j,k,st_idx,st_num;
-        MD_CTX m;
-
-#ifdef NORAND
-        return;
-#endif
+        int i,j,k,st_idx;
+        long md_c[2];
+        unsigned char local_md[MD_DIGEST_LENGTH];
+        EVP_MD_CTX m;
+        int do_not_lock;
+
+        /*
+         * (Based on the rand(3) manpage)
+         *
+         * The input is chopped up into units of 20 bytes (or less for
+         * the last block).  Each of these blocks is run through the hash
+         * function as follows:  The data passed to the hash function
+         * is the current 'md', the same number of bytes from the 'state'
+         * (the location determined by in incremented looping index) as
+         * the current 'block', the new key data 'block', and 'count'
+         * (which is incremented after each use).
+         * The result of this is kept in 'md' and also xored into the
+         * 'state' at the same locations that were used as input into the
+         * hash function.
+         */
+
+        /* check if we already have the lock */
+        if (crypto_lock_rand)
+                {
+                CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
+                do_not_lock = (locking_thread == CRYPTO_thread_id());
+                CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
+                }
+        else
+                do_not_lock = 0;
 
-        CRYPTO_w_lock(CRYPTO_LOCK_RAND);
+        if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
         st_idx=state_index;
-        st_num=state_num;
 
-        state_index=(state_index+num);
+        /* use our own copies of the counters so that even
+         * if a concurrent thread seeds with exactly the
+         * same data and uses the same subarray there's _some_
+         * difference */
+        md_c[0] = md_count[0];
+        md_c[1] = md_count[1];
+
+        memcpy(local_md, md, sizeof md);
+
+        /* state_index <= state_num <= STATE_SIZE */
+        state_index += num;
         if (state_index >= STATE_SIZE)
                 {
                 state_index%=STATE_SIZE;
@@ -159,15 +244,24 @@ int num;
                 if (state_index > state_num)
                         state_num=state_index;
                 }
-        CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+        /* state_index <= state_num <= STATE_SIZE */
 
+        /* state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE]
+         * are what we will use now, but other threads may use them
+         * as well */
+
+        md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
+
+        if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+
+        EVP_MD_CTX_init(&m);
         for (i=0; i<num; i+=MD_DIGEST_LENGTH)
                 {
                 j=(num-i);
                 j=(j > MD_DIGEST_LENGTH)?MD_DIGEST_LENGTH:j;
 
                 MD_Init(&m);
-                MD_Update(&m,md,MD_DIGEST_LENGTH);
+                MD_Update(&m,local_md,MD_DIGEST_LENGTH);
                 k=(st_idx+j)-STATE_SIZE;
                 if (k > 0)
                         {
@@ -178,228 +272,301 @@ int num;
                         MD_Update(&m,&(state[st_idx]),j);
                         
                 MD_Update(&m,buf,j);
-                MD_Final(md,&m);
+                MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
+                MD_Final(&m,local_md);
+                md_c[1]++;
 
-                buf+=j;
+                buf=(const char *)buf + j;
 
                 for (k=0; k<j; k++)
                         {
-                        state[st_idx++]^=md[k];
+                        /* Parallel threads may interfere with this,
+                         * but always each byte of the new state is
+                         * the XOR of some previous value of its
+                         * and local_md (itermediate values may be lost).
+                         * Alway using locking could hurt performance more
+                         * than necessary given that conflicts occur only
+                         * when the total seeding is longer than the random
+                         * state. */
+                        state[st_idx++]^=local_md[k];
                         if (st_idx >= STATE_SIZE)
-                                {
                                 st_idx=0;
-                                st_num=STATE_SIZE;
-                                }
                         }
                 }
-        memset((char *)&m,0,sizeof(m));
+        EVP_MD_CTX_cleanup(&m);
+
+        if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
+        /* Don't just copy back local_md into md -- this could mean that
+         * other thread's seeding remains without effect (except for
+         * the incremented counter).  By XORing it we keep at least as
+         * much entropy as fits into md. */
+        for (k = 0; k < sizeof md; k++)
+                {
+                md[k] ^= local_md[k];
+                }
+        if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
+            entropy += add;
+        if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+        
+#if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32)
+        assert(md_c[1] == md_count[1]);
+#endif
         }
 
-void RAND_bytes(buf,num)
-unsigned char *buf;
-int num;
+static void ssleay_rand_seed(const void *buf, int num)
         {
+        ssleay_rand_add(buf, num, num);
+        }
+
+static int ssleay_rand_bytes(unsigned char *buf, int num)
+        {
+        static volatile int stirred_pool = 0;
         int i,j,k,st_num,st_idx;
-        MD_CTX m;
-        static int init=1;
-        unsigned long l;
-#ifdef DEVRANDOM
-        FILE *fh;
+        int num_ceil;
+        int ok;
+        long md_c[2];
+        unsigned char local_md[MD_DIGEST_LENGTH];
+        EVP_MD_CTX m;
+#ifndef GETPID_IS_MEANINGLESS
+        pid_t curr_pid = getpid();
 #endif
+        int do_stir_pool = 0;
 
 #ifdef PREDICT
-        {
-        static unsigned char val=0;
+        if (rand_predictable)
+                {
+                static unsigned char val=0;
 
-        for (i=0; i<num; i++)
-                buf[i]=val++;
-        return;
-        }
+                for (i=0; i<num; i++)
+                        buf[i]=val++;
+                return(1);
+                }
 #endif
 
+        if (num <= 0)
+                return 1;
+
+        EVP_MD_CTX_init(&m);
+        /* round upwards to multiple of MD_DIGEST_LENGTH/2 */
+        num_ceil = (1 + (num-1)/(MD_DIGEST_LENGTH/2)) * (MD_DIGEST_LENGTH/2);
+
+        /*
+         * (Based on the rand(3) manpage:)
+         *
+         * For each group of 10 bytes (or less), we do the following:
+         *
+         * Input into the hash function the local 'md' (which is initialized from
+         * the global 'md' before any bytes are generated), the bytes that are to
+         * be overwritten by the random bytes, and bytes from the 'state'
+         * (incrementing looping index). From this digest output (which is kept
+         * in 'md'), the top (up to) 10 bytes are returned to the caller and the
+         * bottom 10 bytes are xored into the 'state'.
+         * 
+         * Finally, after we have finished 'num' random bytes for the
+         * caller, 'count' (which is incremented) and the local and global 'md'
+         * are fed into the hash function and the results are kept in the
+         * global 'md'.
+         */
+
         CRYPTO_w_lock(CRYPTO_LOCK_RAND);
 
-        if (init)
+        /* prevent ssleay_rand_bytes() from trying to obtain the lock again */
+        CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
+        locking_thread = CRYPTO_thread_id();
+        CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
+        crypto_lock_rand = 1;
+
+        if (!initialized)
                 {
-                init=0;
-                CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
-                /* put in some default random data, we need more than
-                 * just this */
-                RAND_seed((unsigned char *)&m,sizeof(m));
-#ifndef MSDOS
-                l=getpid();
-                RAND_seed((unsigned char *)&l,sizeof(l));
-                l=getuid();
-                RAND_seed((unsigned char *)&l,sizeof(l));
-#endif
-                l=time(NULL);
-                RAND_seed((unsigned char *)&l,sizeof(l));
-
-/* #ifdef DEVRANDOM */
-                /* 
-                 * Use a random entropy pool device.
-                 * Linux 1.3.x and FreeBSD-Current has 
-                 * this. Use /dev/urandom if you can
-                 * as /dev/random will block if it runs out
-                 * of random entries.
+                RAND_poll();
+                initialized = 1;
+                }
+        
+        if (!stirred_pool)
+                do_stir_pool = 1;
+        
+        ok = (entropy >= ENTROPY_NEEDED);
+        if (!ok)
+                {
+                /* If the PRNG state is not yet unpredictable, then seeing
+                 * the PRNG output may help attackers to determine the new
+                 * state; thus we have to decrease the entropy estimate.
+                 * Once we've had enough initial seeding we don't bother to
+                 * adjust the entropy count, though, because we're not ambitious
+                 * to provide *information-theoretic* randomness.
+                 *
+                 * NOTE: This approach fails if the program forks before
+                 * we have enough entropy. Entropy should be collected
+                 * in a separate input pool and be transferred to the
+                 * output pool only when the entropy limit has been reached.
                  */
-                if ((fh = fopen(DEVRANDOM, "r")) != NULL)
+                entropy -= num;
+                if (entropy < 0)
+                        entropy = 0;
+                }
+
+        if (do_stir_pool)
+                {
+                /* In the output function only half of 'md' remains secret,
+                 * so we better make sure that the required entropy gets
+                 * 'evenly distributed' through 'state', our randomness pool.
+                 * The input function (ssleay_rand_add) chains all of 'md',
+                 * which makes it more suitable for this purpose.
+                 */
+
+                int n = STATE_SIZE; /* so that the complete pool gets accessed */
+                while (n > 0)
                         {
-                        unsigned char tmpbuf[32];
-
-                        fread((unsigned char *)tmpbuf,1,32,fh);
-                        /* we don't care how many bytes we read,
-                         * we will just copy the 'stack' if there is
-                         * nothing else :-) */
-                        fclose(fh);
-                        RAND_seed(tmpbuf,32);
-                        memset(tmpbuf,0,32);
-                        }
-/* #endif */
-#ifdef PURIFY
-                memset(state,0,STATE_SIZE);
-                memset(md,0,MD_DIGEST_LENGTH);
+#if MD_DIGEST_LENGTH > 20
+# error "Please adjust DUMMY_SEED."
 #endif
-                CRYPTO_w_lock(CRYPTO_LOCK_RAND);
+#define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
+                        /* Note that the seed does not matter, it's just that
+                         * ssleay_rand_add expects to have something to hash. */
+                        ssleay_rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
+                        n -= MD_DIGEST_LENGTH;
+                        }
+                if (ok)
+                        stirred_pool = 1;
                 }
 
         st_idx=state_index;
         st_num=state_num;
-        state_index+=num;
+        md_c[0] = md_count[0];
+        md_c[1] = md_count[1];
+        memcpy(local_md, md, sizeof md);
+
+        state_index+=num_ceil;
         if (state_index > state_num)
-                state_index=(state_index%state_num);
+                state_index %= state_num;
 
+        /* state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num]
+         * are now ours (but other threads may use them too) */
+
+        md_count[0] += 1;
+
+        /* before unlocking, we must clear 'crypto_lock_rand' */
+        crypto_lock_rand = 0;
         CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
 
         while (num > 0)
                 {
+                /* num_ceil -= MD_DIGEST_LENGTH/2 */
                 j=(num >= MD_DIGEST_LENGTH/2)?MD_DIGEST_LENGTH/2:num;
                 num-=j;
                 MD_Init(&m);
-                MD_Update(&m,&(md[MD_DIGEST_LENGTH/2]),MD_DIGEST_LENGTH/2);
+#ifndef GETPID_IS_MEANINGLESS
+                if (curr_pid) /* just in the first iteration to save time */
+                        {
+                        MD_Update(&m,(unsigned char*)&curr_pid,sizeof curr_pid);
+                        curr_pid = 0;
+                        }
+#endif
+                MD_Update(&m,local_md,MD_DIGEST_LENGTH);
+                MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
 #ifndef PURIFY
                 MD_Update(&m,buf,j); /* purify complains */
 #endif
-                k=(st_idx+j)-st_num;
+                k=(st_idx+MD_DIGEST_LENGTH/2)-st_num;
                 if (k > 0)
                         {
-                        MD_Update(&m,&(state[st_idx]),j-k);
+                        MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2-k);
                         MD_Update(&m,&(state[0]),k);
                         }
                 else
-                        MD_Update(&m,&(state[st_idx]),j);
-                MD_Final(md,&m);
+                        MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2);
+                MD_Final(&m,local_md);
 
-                for (i=0; i<j; i++)
+                for (i=0; i<MD_DIGEST_LENGTH/2; i++)
                         {
+                        state[st_idx++]^=local_md[i]; /* may compete with other threads */
                         if (st_idx >= st_num)
                                 st_idx=0;
-                        state[st_idx++]^=md[i];
-                        *(buf++)=md[i+MD_DIGEST_LENGTH/2];
+                        if (i < j)
+                                *(buf++)=local_md[i+MD_DIGEST_LENGTH/2];
                         }
                 }
 
         MD_Init(&m);
-        MD_Update(&m,(unsigned char *)&md_count,sizeof(md_count)); md_count++;
+        MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
+        MD_Update(&m,local_md,MD_DIGEST_LENGTH);
+        CRYPTO_w_lock(CRYPTO_LOCK_RAND);
         MD_Update(&m,md,MD_DIGEST_LENGTH);
-        MD_Final(md,&m);
-        memset(&m,0,sizeof(m));
+        MD_Final(&m,md);
+        CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+
+        EVP_MD_CTX_cleanup(&m);
+        if (ok)
+                return(1);
+        else
+                {
+                RANDerr(RAND_F_SSLEAY_RAND_BYTES,RAND_R_PRNG_NOT_SEEDED);
+                ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
+                        "http://www.openssl.org/support/faq.html");
+                return(0);
+                }
         }
 
-#ifdef WINDOWS
-#include <windows.h>
-#include <rand.h>
+/* pseudo-random bytes that are guaranteed to be unique but not
+   unpredictable */
+static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num) 
+        {
+        int ret;
+        unsigned long err;
 
-/*****************************************************************************
- * Initialisation function for the SSL random generator.  Takes the contents
- * of the screen as random seed.
- *
- * Created 960901 by Gertjan van Oosten, gertjan@West.NL, West Consulting B.V.
- *
- * Code adapted from
- * <URL:http://www.microsoft.com/kb/developr/win_dk/q97193.htm>;
- * the original copyright message is:
- *
-//   (C) Copyright Microsoft Corp. 1993.  All rights reserved.
-//
-//   You have a royalty-free right to use, modify, reproduce and
-//   distribute the Sample Files (and/or any modified version) in
-//   any way you find useful, provided that you agree that
-//   Microsoft has no warranty obligations or liability for any
-//   Sample Application Files which are modified.
- */
-/*
- * I have modified the loading of bytes via RAND_seed() mechanism since
- * the origional would have been very very CPU intensive since RAND_seed()
- * does an MD5 per 16 bytes of input.  The cost to digest 16 bytes is the same
- * as that to digest 56 bytes.  So under the old system, a screen of
- * 1024*768*256 would have been CPU cost of approximatly 49,000 56 byte MD5
- * digests or digesting 2.7 mbytes.  What I have put in place would
- * be 48 16k MD5 digests, or efectivly 48*16+48 MD5 bytes or 816 kbytes
- * or about 3.5 times as much.
- * - eric 
- */
-void RAND_screen(void)
-{
-  HDC           hScrDC;         /* screen DC */
-  HDC           hMemDC;         /* memory DC */
-  HBITMAP       hBitmap;        /* handle for our bitmap */
-  HBITMAP       hOldBitmap;     /* handle for previous bitmap */
-  BITMAP        bm;             /* bitmap properties */
-  unsigned int  size;           /* size of bitmap */
-  char          *bmbits;        /* contents of bitmap */
-  int           w;              /* screen width */
-  int           h;              /* screen height */
-  int           y;              /* y-coordinate of screen lines to grab */
-  int           n = 16;         /* number of screen lines to grab at a time */
-
-  /* Create a screen DC and a memory DC compatible to screen DC */
-  hScrDC = CreateDC("DISPLAY", NULL, NULL, NULL);
-  hMemDC = CreateCompatibleDC(hScrDC);
-
-  /* Get screen resolution */
-  w = GetDeviceCaps(hScrDC, HORZRES);
-  h = GetDeviceCaps(hScrDC, VERTRES);
-
-  /* Create a bitmap compatible with the screen DC */
-  hBitmap = CreateCompatibleBitmap(hScrDC, w, n);
-
-  /* Select new bitmap into memory DC */
-  hOldBitmap = SelectObject(hMemDC, hBitmap);
-
-  /* Get bitmap properties */
-  GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&bm);
-  size = (unsigned int)bm.bmWidthBytes * bm.bmHeight * bm.bmPlanes;
-
-  bmbits = Malloc(size);
-  if (bmbits) {
-    /* Now go through the whole screen, repeatedly grabbing n lines */
-    for (y = 0; y < h-n; y += n)
-        {
-        unsigned char md[MD_DIGEST_LENGTH];
-
-        /* Bitblt screen DC to memory DC */
-        BitBlt(hMemDC, 0, 0, w, n, hScrDC, 0, y, SRCCOPY);
-
-        /* Copy bitmap bits from memory DC to bmbits */
-        GetBitmapBits(hBitmap, size, bmbits);
-
-        /* Get the MD5 of the bitmap */
-        MD5(bmbits,size,md);
-
-        /* Seed the random generator with the MD5 digest */
-        RAND_seed(md, MD_DIGEST_LENGTH);
+        ret = RAND_bytes(buf, num);
+        if (ret == 0)
+                {
+                err = ERR_peek_error();
+                if (ERR_GET_LIB(err) == ERR_LIB_RAND &&
+                    ERR_GET_REASON(err) == RAND_R_PRNG_NOT_SEEDED)
+                        (void)ERR_get_error();
+                }
+        return (ret);
         }
 
-    Free(bmbits);
-  }
+static int ssleay_rand_status(void)
+        {
+        int ret;
+        int do_not_lock;
 
-  /* Select old bitmap back into memory DC */
-  hBitmap = SelectObject(hMemDC, hOldBitmap);
+        /* check if we already have the lock
+         * (could happen if a RAND_poll() implementation calls RAND_status()) */
+        if (crypto_lock_rand)
+                {
+                CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
+                do_not_lock = (locking_thread == CRYPTO_thread_id());
+                CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
+                }
+        else
+                do_not_lock = 0;
+        
+        if (!do_not_lock)
+                {
+                CRYPTO_w_lock(CRYPTO_LOCK_RAND);
+                
+                /* prevent ssleay_rand_bytes() from trying to obtain the lock again */
+                CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
+                locking_thread = CRYPTO_thread_id();
+                CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
+                crypto_lock_rand = 1;
+                }
+        
+        if (!initialized)
+                {
+                RAND_poll();
+                initialized = 1;
+                }
 
-  /* Clean up */
-  DeleteObject(hBitmap);
-  DeleteDC(hMemDC);
-  DeleteDC(hScrDC);
-}
-#endif
+        ret = entropy >= ENTROPY_NEEDED;
+
+        if (!do_not_lock)
+                {
+                /* before unlocking, we must clear 'crypto_lock_rand' */
+                crypto_lock_rand = 0;
+                
+                CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+                }
+        
+        return ret;
+        }