Return if ssleay_rand_add called with zero num.
[openssl.git] / crypto / rand / md_rand.c
index d3261a0..67ac5ac 100644 (file)
@@ -56,7 +56,7 @@
  * [including the GNU Public Licence.]
  */
 /* ====================================================================
- * Copyright (c) 1998-2000 The OpenSSL Project.  All rights reserved.
+ * 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
  *
  */
 
+#define OPENSSL_FIPSAPI
+
 #ifdef MD_RAND_DEBUG
 # ifndef NDEBUG
 #   define NDEBUG
 
 #include "e_os.h"
 
+#if !(defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYSNAME_DSPBIOS))
+# include <sys/time.h>
+#endif
+#if defined(OPENSSL_SYS_VXWORKS)
+# include <time.h>
+#endif
+
+#include <openssl/crypto.h>
 #include <openssl/rand.h>
 #include "rand_lcl.h"
 
-#include <openssl/crypto.h>
 #include <openssl/err.h>
 
+#ifdef OPENSSL_FIPS
+#include <openssl/fips.h>
+#endif
+
 #ifdef BN_DEBUG
 # define PREDICT
 #endif
@@ -141,27 +154,32 @@ static long md_count[2]={0,0};
 static double entropy=0;
 static int initialized=0;
 
-/* This should be set to 1 only when ssleay_rand_add() is called inside
-   an already locked state, so it doesn't try to lock and thereby cause
-   a hang.  And it should always be reset back to 0 before unlocking. */
-static int add_do_not_lock=0;
+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 CRYPTO_THREADID locking_threadid; /* valid iff crypto_lock_rand is set */
+
 
 #ifdef PREDICT
 int rand_predictable=0;
 #endif
 
-const char *RAND_version="RAND" OPENSSL_VERSION_PTEXT;
+const char RAND_version[]="RAND" OPENSSL_VERSION_PTEXT;
+
+static void rand_hw_seed(EVP_MD_CTX *ctx);
 
 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_seed(const void *buf, int num);
+static int ssleay_rand_add(const void *buf, int num, double add_entropy);
+static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo);
+static int ssleay_rand_nopseudo_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={
+static RAND_METHOD rand_ssleay_meth={
        ssleay_rand_seed,
-       ssleay_rand_bytes,
+       ssleay_rand_nopseudo_bytes,
        ssleay_rand_cleanup,
        ssleay_rand_add,
        ssleay_rand_pseudo_bytes,
@@ -175,22 +193,27 @@ RAND_METHOD *RAND_SSLeay(void)
 
 static void ssleay_rand_cleanup(void)
        {
-       memset(state,0,sizeof(state));
+       OPENSSL_cleanse(state,sizeof(state));
        state_num=0;
        state_index=0;
-       memset(md,0,MD_DIGEST_LENGTH);
+       OPENSSL_cleanse(md,MD_DIGEST_LENGTH);
        md_count[0]=0;
        md_count[1]=0;
        entropy=0;
        initialized=0;
        }
 
-static void ssleay_rand_add(const void *buf, int num, double add)
+static int ssleay_rand_add(const void *buf, int num, double add)
        {
        int i,j,k,st_idx;
        long md_c[2];
        unsigned char local_md[MD_DIGEST_LENGTH];
-       MD_CTX m;
+       EVP_MD_CTX m;
+       int do_not_lock;
+       int rv = 0;
+
+       if (!num)
+               return;
 
        /*
         * (Based on the rand(3) manpage)
@@ -207,7 +230,20 @@ static void ssleay_rand_add(const void *buf, int num, double add)
          * hash function.
         */
 
-       if (!add_do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
+       EVP_MD_CTX_init(&m);
+       /* check if we already have the lock */
+       if (crypto_lock_rand)
+               {
+               CRYPTO_THREADID cur;
+               CRYPTO_THREADID_current(&cur);
+               CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
+               do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
+               CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
+               }
+       else
+               do_not_lock = 0;
+
+       if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
        st_idx=state_index;
 
        /* use our own copies of the counters so that even
@@ -239,27 +275,43 @@ static void ssleay_rand_add(const void *buf, int num, double add)
 
        md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
 
-       if (!add_do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+       if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
 
        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,local_md,MD_DIGEST_LENGTH);
+               if (!MD_Init(&m))
+                       goto err;
+               if (!MD_Update(&m,local_md,MD_DIGEST_LENGTH))
+                       goto err;
                k=(st_idx+j)-STATE_SIZE;
                if (k > 0)
                        {
-                       MD_Update(&m,&(state[st_idx]),j-k);
-                       MD_Update(&m,&(state[0]),k);
+                       if (!MD_Update(&m,&(state[st_idx]),j-k))
+                               goto err;
+                       if (!MD_Update(&m,&(state[0]),k))
+                               goto err;
                        }
                else
-                       MD_Update(&m,&(state[st_idx]),j);
-                       
-               MD_Update(&m,buf,j);
-               MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
-               MD_Final(local_md,&m);
+                       if (!MD_Update(&m,&(state[st_idx]),j))
+                               goto err;
+
+               /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
+               if (!MD_Update(&m,buf,j))
+                       goto err;
+               /* We know that line may cause programs such as
+                  purify and valgrind to complain about use of
+                  uninitialized data.  The problem is not, it's
+                  with the caller.  Removing that line will make
+                  sure you get really bad randomness and thereby
+                  other problems such as very insecure keys. */
+
+               if (!MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c)))
+                       goto err;
+               if (!MD_Final(&m,local_md))
+                       goto err;
                md_c[1]++;
 
                buf=(const char *)buf + j;
@@ -279,43 +331,68 @@ static void ssleay_rand_add(const void *buf, int num, double add)
                                st_idx=0;
                        }
                }
-       memset((char *)&m,0,sizeof(m));
 
-       if (!add_do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
+       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++)
+       for (k = 0; k < (int)sizeof(md); k++)
                {
                md[k] ^= local_md[k];
                }
        if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
            entropy += add;
-       if (!add_do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+       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
+       rv = 1;
+       err:
+       EVP_MD_CTX_cleanup(&m);
+       return rv;
        }
 
-static void ssleay_rand_seed(const void *buf, int num)
+static int ssleay_rand_seed(const void *buf, int num)
        {
-       ssleay_rand_add(buf, num, num);
+       return ssleay_rand_add(buf, num, (double)num);
        }
 
-static int ssleay_rand_bytes(unsigned char *buf, int num)
+static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo)
        {
        static volatile int stirred_pool = 0;
        int i,j,k,st_num,st_idx;
+       int num_ceil;
        int ok;
        long md_c[2];
        unsigned char local_md[MD_DIGEST_LENGTH];
-       MD_CTX m;
+       EVP_MD_CTX m;
 #ifndef GETPID_IS_MEANINGLESS
        pid_t curr_pid = getpid();
 #endif
+       time_t curr_time = time(NULL);
        int do_stir_pool = 0;
+/* time value for various platforms */
+#ifdef OPENSSL_SYS_WIN32
+       FILETIME tv;
+# ifdef _WIN32_WCE
+       SYSTEMTIME t;
+       GetSystemTime(&t);
+       SystemTimeToFileTime(&t, &tv);
+# else
+       GetSystemTimeAsFileTime(&tv);
+# endif
+#elif defined(OPENSSL_SYS_VXWORKS)
+       struct timespec tv;
+       clock_gettime(CLOCK_REALTIME, &ts);
+#elif defined(OPENSSL_SYSNAME_DSPBIOS)
+       unsigned long long tv, OPENSSL_rdtsc();
+       tv = OPENSSL_rdtsc();
+#else
+       struct timeval tv;
+       gettimeofday(&tv, NULL);
+#endif
 
 #ifdef PREDICT
        if (rand_predictable)
@@ -328,33 +405,45 @@ static int ssleay_rand_bytes(unsigned char *buf, int num)
                }
 #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 top 10 bytes from 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 (up to) 10 bytes are xored
-        * into the 'state'.
+        * 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'.
         */
 
-       if (!initialized)
-               RAND_poll();
-
        CRYPTO_w_lock(CRYPTO_LOCK_RAND);
-       add_do_not_lock = 1;    /* Since we call ssleay_rand_add while in
-                                  this locked state. */
 
-       initialized = 1;
+       /* prevent ssleay_rand_bytes() from trying to obtain the lock again */
+       CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
+       CRYPTO_THREADID_current(&locking_threadid);
+       CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
+       crypto_lock_rand = 1;
+
+       if (!initialized)
+               {
+               RAND_poll();
+               initialized = 1;
+               }
+       
        if (!stirred_pool)
                do_stir_pool = 1;
        
@@ -380,11 +469,11 @@ static int ssleay_rand_bytes(unsigned char *buf, int num)
 
        if (do_stir_pool)
                {
-               /* Our output function chains only half of 'md', 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.
+               /* 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 */
@@ -409,103 +498,250 @@ static int ssleay_rand_bytes(unsigned char *buf, int num)
        md_c[1] = md_count[1];
        memcpy(local_md, md, sizeof md);
 
-       state_index+=num;
+       state_index+=num_ceil;
        if (state_index > state_num)
                state_index %= state_num;
 
-       /* state[st_idx], ..., state[(st_idx + num - 1) % st_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;
 
-       add_do_not_lock = 0;    /* If this would ever be forgotten, we can
-                                  expect any evil god to eat our souls. */
+       /* 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);
+               if (!MD_Init(&m))
+                       goto err;
 #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);
+                       if (!MD_Update(&m,(unsigned char*)&curr_pid,
+                                      sizeof curr_pid))
+                               goto err;
                        curr_pid = 0;
                        }
 #endif
-               MD_Update(&m,&(local_md[MD_DIGEST_LENGTH/2]),MD_DIGEST_LENGTH/2);
-               MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
-#ifndef PURIFY
-               MD_Update(&m,buf,j); /* purify complains */
+               if (curr_time) /* just in the first iteration to save time */
+                       {
+                       if (!MD_Update(&m,(unsigned char*)&curr_time,
+                                      sizeof curr_time))
+                               goto err;
+                       if (!MD_Update(&m,(unsigned char*)&tv,
+                                      sizeof tv))
+                               goto err;
+                       curr_time = 0;
+                       rand_hw_seed(&m);
+                       }
+               if (!MD_Update(&m,local_md,MD_DIGEST_LENGTH))
+                       goto err;
+               if (!MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c)))
+                       goto err;
+
+#ifndef PURIFY /* purify complains */
+               /* The following line uses the supplied buffer as a small
+                * source of entropy: since this buffer is often uninitialised
+                * it may cause programs such as purify or valgrind to
+                * complain. So for those builds it is not used: the removal
+                * of such a small source of entropy has negligible impact on
+                * security.
+                */
+               if (!MD_Update(&m,buf,j))
+                       goto err;
 #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[0]),k);
+                       if (!MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2-k))
+                               goto err;
+                       if (!MD_Update(&m,&(state[0]),k))
+                               goto err;
                        }
                else
-                       MD_Update(&m,&(state[st_idx]),j);
-               MD_Final(local_md,&m);
+                       if (!MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2))
+                               goto err;
+               if (!MD_Final(&m,local_md))
+                       goto err;
 
-               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 */
-                       *(buf++)=local_md[i+MD_DIGEST_LENGTH/2];
                        if (st_idx >= st_num)
                                st_idx=0;
+                       if (i < j)
+                               *(buf++)=local_md[i+MD_DIGEST_LENGTH/2];
                        }
                }
 
-       MD_Init(&m);
-       MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
-       MD_Update(&m,local_md,MD_DIGEST_LENGTH);
+       if (!MD_Init(&m)
+               || !MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c))
+               || !MD_Update(&m,local_md,MD_DIGEST_LENGTH))
+               goto err;
        CRYPTO_w_lock(CRYPTO_LOCK_RAND);
-       MD_Update(&m,md,MD_DIGEST_LENGTH);
-       MD_Final(md,&m);
+       if (!MD_Update(&m,md,MD_DIGEST_LENGTH) || !MD_Final(&m,md))
+               {
+               CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+               goto err;
+               }
        CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
 
-       memset(&m,0,sizeof(m));
+       EVP_MD_CTX_cleanup(&m);
        if (ok)
                return(1);
-       else
+       else if (pseudo)
+               return 0;
+       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);
                }
+       err:
+       EVP_MD_CTX_cleanup(&m);
+       RANDerr(RAND_F_SSLEAY_RAND_BYTES,ERR_R_EVP_LIB);
+       return 0;
+
+       }
+
+static int ssleay_rand_nopseudo_bytes(unsigned char *buf, int num)
+       {
+       return ssleay_rand_bytes(buf, num, 0);
        }
 
 /* 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, err;
-
-       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);
+       return ssleay_rand_bytes(buf, num, 1);
        }
 
 static int ssleay_rand_status(void)
        {
+       CRYPTO_THREADID cur;
        int ret;
+       int do_not_lock;
 
+       CRYPTO_THREADID_current(&cur);
+       /* 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 = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
+               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);
+               CRYPTO_THREADID_cpy(&locking_threadid, &cur);
+               CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
+               crypto_lock_rand = 1;
+               }
+       
        if (!initialized)
+               {
                RAND_poll();
+               initialized = 1;
+               }
 
-       CRYPTO_w_lock(CRYPTO_LOCK_RAND);
-       initialized = 1;
        ret = entropy >= ENTROPY_NEEDED;
-       CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
 
+       if (!do_not_lock)
+               {
+               /* before unlocking, we must clear 'crypto_lock_rand' */
+               crypto_lock_rand = 0;
+               
+               CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+               }
+       
        return ret;
        }
+
+/* rand_hw_seed: get seed data from any available hardware RNG.
+ * only currently supports rdrand.
+ */
+
+/* Adapted from eng_rdrand.c */
+
+#if (defined(__i386)   || defined(__i386__)   || defined(_M_IX86) || \
+     defined(__x86_64) || defined(__x86_64__) || \
+     defined(_M_AMD64) || defined (_M_X64)) && defined(OPENSSL_CPUID_OBJ)
+
+#define RDRAND_CALLS   4
+
+size_t OPENSSL_ia32_rdrand(void);
+extern unsigned int OPENSSL_ia32cap_P[];
+
+static void rand_hw_seed(EVP_MD_CTX *ctx)
+       {
+       int i;
+       if (!(OPENSSL_ia32cap_P[1] & (1<<(62-32))))
+               return;
+       for (i = 0; i < RDRAND_CALLS; i++)
+               {
+               size_t rnd;
+               rnd = OPENSSL_ia32_rdrand();
+               if (rnd == 0)
+                       return;
+               MD_Update(ctx, (unsigned char *)&rnd, sizeof(size_t));
+               }
+       }
+
+/* XOR an existing buffer with random data */
+
+void rand_hw_xor(unsigned char *buf, size_t num)
+       {
+       size_t rnd;
+       if (!(OPENSSL_ia32cap_P[1] & (1<<(62-32))))
+               return;
+       while (num >= sizeof(size_t))
+               {
+               rnd = OPENSSL_ia32_rdrand();
+               if (rnd == 0)
+                       return;
+               *((size_t *)buf) ^= rnd;
+               buf += sizeof(size_t);
+               num -= sizeof(size_t);
+               }
+       if (num)
+               {
+               rnd = OPENSSL_ia32_rdrand();
+               if (rnd == 0)
+                       return;
+               while(num)
+                       {
+                       *buf ^= rnd & 0xff;
+                       rnd >>= 8;
+                       buf++;
+                       num--;
+                       }
+               }
+       }
+
+
+#else
+
+static void rand_hw_seed(EVP_MD_CTX *ctx)
+       {
+       return;
+       }
+
+void rand_hw_xor(unsigned char *buf, size_t num)
+       {
+       return;
+       }
+
+#endif