Return if ssleay_rand_add called with zero num.

[openssl.git] / crypto / rand / md_rand.c

diff --git a/crypto/rand/md_rand.c b/crypto/rand/md_rand.c
index 810b4c2d4a61a25d4635453fa9ed6ab83e2c5025..aee1c30b0a9bb4a24cc1dd90694f25a0ed852c5b 100644 (file)
--- a/crypto/rand/md_rand.c
+++ b/crypto/rand/md_rand.c
@@ -109,6 +109,8 @@
  *
  */
 
+#define OPENSSL_FIPSEVP
+
 #ifdef MD_RAND_DEBUG
 # ifndef NDEBUG
 #   define NDEBUG
@@ -121,10 +123,10 @@
 
 #include "e_os.h"
 
+#include <openssl/crypto.h>
 #include <openssl/rand.h>
 #include "rand_lcl.h"
 
-#include <openssl/crypto.h>
 #include <openssl/err.h>
 
 #ifdef BN_DEBUG
@@ -157,13 +159,14 @@ 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_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={
        ssleay_rand_seed,
-       ssleay_rand_bytes,
+       ssleay_rand_nopseudo_bytes,
        ssleay_rand_cleanup,
        ssleay_rand_add,
        ssleay_rand_pseudo_bytes,
@@ -195,6 +198,9 @@ static void ssleay_rand_add(const void *buf, int num, double add)
        EVP_MD_CTX m;
        int do_not_lock;
 
+       if (!num)
+               return;
+
        /*
         * (Based on the rand(3) manpage)
         *
@@ -272,8 +278,16 @@ static void ssleay_rand_add(const void *buf, int num, double add)
                        }
                else
                        MD_Update(&m,&(state[st_idx]),j);
-                       
+
+               /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
                MD_Update(&m,buf,j);
+               /* 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. */
+
                MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
                MD_Final(&m,local_md);
                md_c[1]++;
@@ -320,7 +334,7 @@ static void ssleay_rand_seed(const void *buf, int num)
        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;
@@ -369,8 +383,11 @@ static int ssleay_rand_bytes(unsigned char *buf, int num)
         * are fed into the hash function and the results are kept in the
         * global 'md'.
         */
-
-       CRYPTO_w_lock(CRYPTO_LOCK_RAND);
+#ifdef OPENSSL_FIPS
+       /* NB: in FIPS mode we are already under a lock */
+       if (!FIPS_mode())
+#endif
+               CRYPTO_w_lock(CRYPTO_LOCK_RAND);
 
        /* prevent ssleay_rand_bytes() from trying to obtain the lock again */
        CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
@@ -449,7 +466,10 @@ static int ssleay_rand_bytes(unsigned char *buf, int num)
 
        /* before unlocking, we must clear 'crypto_lock_rand' */
        crypto_lock_rand = 0;
-       CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+#ifdef OPENSSL_FIPS
+       if (!FIPS_mode())
+#endif
+               CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
 
        while (num > 0)
                {
@@ -466,9 +486,18 @@ static int ssleay_rand_bytes(unsigned char *buf, int num)
 #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 */
+
+#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.
+                */
+               MD_Update(&m,buf,j);
 #endif
+
                k=(st_idx+MD_DIGEST_LENGTH/2)-st_num;
                if (k > 0)
                        {
@@ -492,15 +521,23 @@ static int ssleay_rand_bytes(unsigned char *buf, int num)
        MD_Init(&m);
        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);
+#ifdef OPENSSL_FIPS
+       if (!FIPS_mode())
+#endif
+               CRYPTO_w_lock(CRYPTO_LOCK_RAND);
        MD_Update(&m,md,MD_DIGEST_LENGTH);
        MD_Final(&m,md);
-       CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+#ifdef OPENSSL_FIPS
+       if (!FIPS_mode())
+#endif
+               CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
 
        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, "
@@ -509,22 +546,16 @@ static int ssleay_rand_bytes(unsigned char *buf, int num)
                }
        }
 
+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;
-       unsigned long 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)
-                       ERR_clear_error();
-               }
-       return (ret);
+       return ssleay_rand_bytes(buf, num, 1);
        }
 
 static int ssleay_rand_status(void)