test/bntest.c:986: error: NULL_DEREFERENCE
  pointer `a` last assigned on line 980 could be null and is dereferenced by call to `BN_set_word()` at line 986, column 5.
Showing all 113 steps of the trace


test/bntest.c:975:1: start of procedure test_mod_exp()
973.   }
974.   
975. > int test_mod_exp(BIO *bp, BN_CTX *ctx)
976.   {
977.       BIGNUM *a, *b, *c, *d, *e;

test/bntest.c:980:5: 
978.       int i;
979.   
980. >     a = BN_new();
981.       b = BN_new();
982.       c = BN_new();

crypto/bn/bn_lib.c:276:1: start of procedure BN_new()
  274.   }
  275.   
  276. > BIGNUM *BN_new(void)
  277.   {
  278.       BIGNUM *ret;

crypto/bn/bn_lib.c:280:9: 
  278.       BIGNUM *ret;
  279.   
  280. >     if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
  282.           return (NULL);

crypto/mem.c:156:1: start of procedure CRYPTO_zalloc()
    154.   }
    155.   
    156. > void *CRYPTO_zalloc(size_t num, const char *file, int line)
    157.   {
    158.       void *ret = CRYPTO_malloc(num, file, line);

crypto/mem.c:158:5: 
    156.   void *CRYPTO_zalloc(size_t num, const char *file, int line)
    157.   {
    158. >     void *ret = CRYPTO_malloc(num, file, line);
    159.   
    160.       if (ret != NULL)

crypto/mem.c:119:1: start of procedure CRYPTO_malloc()
      117.   }
      118.   
      119. > void *CRYPTO_malloc(size_t num, const char *file, int line)
      120.   {
      121.       void *ret = NULL;

crypto/mem.c:121:5: 
      119.   void *CRYPTO_malloc(size_t num, const char *file, int line)
      120.   {
      121. >     void *ret = NULL;
      122.   
      123.       if (num <= 0)

crypto/mem.c:123:9: Taking false branch
      121.       void *ret = NULL;
      122.   
      123.       if (num <= 0)
                     ^
      124.           return NULL;
      125.   

crypto/mem.c:126:5: 
      124.           return NULL;
      125.   
      126. >     allow_customize = 0;
      127.   #ifndef OPENSSL_NO_CRYPTO_MDEBUG
      128.       if (call_malloc_debug) {

crypto/mem.c:136:5: 
      134.       }
      135.   #else
      136. >     (void)file;
      137.       (void)line;
      138.       ret = malloc(num);

crypto/mem.c:137:5: 
      135.   #else
      136.       (void)file;
      137. >     (void)line;
      138.       ret = malloc(num);
      139.   #endif

crypto/mem.c:138:5: 
      136.       (void)file;
      137.       (void)line;
      138. >     ret = malloc(num);
      139.   #endif
      140.   

crypto/mem.c:153:5: 
      151.   #endif
      152.   
      153. >     return ret;
      154.   }
      155.   

crypto/mem.c:154:1: return from a call to CRYPTO_malloc
      152.   
      153.       return ret;
      154. > }
      155.   
      156.   void *CRYPTO_zalloc(size_t num, const char *file, int line)

crypto/mem.c:160:9: Taking false branch
    158.       void *ret = CRYPTO_malloc(num, file, line);
    159.   
    160.       if (ret != NULL)
                   ^
    161.           memset(ret, 0, num);
    162.       return ret;

crypto/mem.c:162:5: 
    160.       if (ret != NULL)
    161.           memset(ret, 0, num);
    162. >     return ret;
    163.   }
    164.   

crypto/mem.c:163:1: return from a call to CRYPTO_zalloc
    161.           memset(ret, 0, num);
    162.       return ret;
    163. > }
    164.   
    165.   void *CRYPTO_realloc(void *str, size_t num, const char *file, int line)

crypto/bn/bn_lib.c:280:9: Taking true branch
  278.       BIGNUM *ret;
  279.   
  280.       if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
                 ^
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
  282.           return (NULL);

crypto/bn/bn_lib.c:281:9: Skipping ERR_put_error(): empty list of specs
  279.   
  280.       if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
                 ^
  282.           return (NULL);
  283.       }

crypto/bn/bn_lib.c:282:9: 
  280.       if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
  282. >         return (NULL);
  283.       }
  284.       ret->flags = BN_FLG_MALLOCED;

crypto/bn/bn_lib.c:287:1: return from a call to BN_new
  285.       bn_check_top(ret);
  286.       return (ret);
  287. > }
  288.   
  289.    BIGNUM *BN_secure_new(void)

test/bntest.c:981:5: 
979.   
980.       a = BN_new();
981. >     b = BN_new();
982.       c = BN_new();
983.       d = BN_new();

crypto/bn/bn_lib.c:276:1: start of procedure BN_new()
  274.   }
  275.   
  276. > BIGNUM *BN_new(void)
  277.   {
  278.       BIGNUM *ret;

crypto/bn/bn_lib.c:280:9: 
  278.       BIGNUM *ret;
  279.   
  280. >     if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
  282.           return (NULL);

crypto/mem.c:156:1: start of procedure CRYPTO_zalloc()
    154.   }
    155.   
    156. > void *CRYPTO_zalloc(size_t num, const char *file, int line)
    157.   {
    158.       void *ret = CRYPTO_malloc(num, file, line);

crypto/mem.c:158:5: 
    156.   void *CRYPTO_zalloc(size_t num, const char *file, int line)
    157.   {
    158. >     void *ret = CRYPTO_malloc(num, file, line);
    159.   
    160.       if (ret != NULL)

crypto/mem.c:119:1: start of procedure CRYPTO_malloc()
      117.   }
      118.   
      119. > void *CRYPTO_malloc(size_t num, const char *file, int line)
      120.   {
      121.       void *ret = NULL;

crypto/mem.c:121:5: 
      119.   void *CRYPTO_malloc(size_t num, const char *file, int line)
      120.   {
      121. >     void *ret = NULL;
      122.   
      123.       if (num <= 0)

crypto/mem.c:123:9: Taking false branch
      121.       void *ret = NULL;
      122.   
      123.       if (num <= 0)
                     ^
      124.           return NULL;
      125.   

crypto/mem.c:126:5: 
      124.           return NULL;
      125.   
      126. >     allow_customize = 0;
      127.   #ifndef OPENSSL_NO_CRYPTO_MDEBUG
      128.       if (call_malloc_debug) {

crypto/mem.c:136:5: 
      134.       }
      135.   #else
      136. >     (void)file;
      137.       (void)line;
      138.       ret = malloc(num);

crypto/mem.c:137:5: 
      135.   #else
      136.       (void)file;
      137. >     (void)line;
      138.       ret = malloc(num);
      139.   #endif

crypto/mem.c:138:5: 
      136.       (void)file;
      137.       (void)line;
      138. >     ret = malloc(num);
      139.   #endif
      140.   

crypto/mem.c:153:5: 
      151.   #endif
      152.   
      153. >     return ret;
      154.   }
      155.   

crypto/mem.c:154:1: return from a call to CRYPTO_malloc
      152.   
      153.       return ret;
      154. > }
      155.   
      156.   void *CRYPTO_zalloc(size_t num, const char *file, int line)

crypto/mem.c:160:9: Taking true branch
    158.       void *ret = CRYPTO_malloc(num, file, line);
    159.   
    160.       if (ret != NULL)
                   ^
    161.           memset(ret, 0, num);
    162.       return ret;

crypto/mem.c:161:9: 
    159.   
    160.       if (ret != NULL)
    161. >         memset(ret, 0, num);
    162.       return ret;
    163.   }

crypto/mem.c:162:5: 
    160.       if (ret != NULL)
    161.           memset(ret, 0, num);
    162. >     return ret;
    163.   }
    164.   

crypto/mem.c:163:1: return from a call to CRYPTO_zalloc
    161.           memset(ret, 0, num);
    162.       return ret;
    163. > }
    164.   
    165.   void *CRYPTO_realloc(void *str, size_t num, const char *file, int line)

crypto/bn/bn_lib.c:280:9: Taking false branch
  278.       BIGNUM *ret;
  279.   
  280.       if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
                 ^
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
  282.           return (NULL);

crypto/bn/bn_lib.c:284:5: 
  282.           return (NULL);
  283.       }
  284. >     ret->flags = BN_FLG_MALLOCED;
  285.       bn_check_top(ret);
  286.       return (ret);

crypto/bn/bn_lib.c:286:5: 
  284.       ret->flags = BN_FLG_MALLOCED;
  285.       bn_check_top(ret);
  286. >     return (ret);
  287.   }
  288.   

crypto/bn/bn_lib.c:287:1: return from a call to BN_new
  285.       bn_check_top(ret);
  286.       return (ret);
  287. > }
  288.   
  289.    BIGNUM *BN_secure_new(void)

test/bntest.c:982:5: 
980.       a = BN_new();
981.       b = BN_new();
982. >     c = BN_new();
983.       d = BN_new();
984.       e = BN_new();

crypto/bn/bn_lib.c:276:1: start of procedure BN_new()
  274.   }
  275.   
  276. > BIGNUM *BN_new(void)
  277.   {
  278.       BIGNUM *ret;

crypto/bn/bn_lib.c:280:9: 
  278.       BIGNUM *ret;
  279.   
  280. >     if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
  282.           return (NULL);

crypto/mem.c:156:1: start of procedure CRYPTO_zalloc()
    154.   }
    155.   
    156. > void *CRYPTO_zalloc(size_t num, const char *file, int line)
    157.   {
    158.       void *ret = CRYPTO_malloc(num, file, line);

crypto/mem.c:158:5: 
    156.   void *CRYPTO_zalloc(size_t num, const char *file, int line)
    157.   {
    158. >     void *ret = CRYPTO_malloc(num, file, line);
    159.   
    160.       if (ret != NULL)

crypto/mem.c:119:1: start of procedure CRYPTO_malloc()
      117.   }
      118.   
      119. > void *CRYPTO_malloc(size_t num, const char *file, int line)
      120.   {
      121.       void *ret = NULL;

crypto/mem.c:121:5: 
      119.   void *CRYPTO_malloc(size_t num, const char *file, int line)
      120.   {
      121. >     void *ret = NULL;
      122.   
      123.       if (num <= 0)

crypto/mem.c:123:9: Taking false branch
      121.       void *ret = NULL;
      122.   
      123.       if (num <= 0)
                     ^
      124.           return NULL;
      125.   

crypto/mem.c:126:5: 
      124.           return NULL;
      125.   
      126. >     allow_customize = 0;
      127.   #ifndef OPENSSL_NO_CRYPTO_MDEBUG
      128.       if (call_malloc_debug) {

crypto/mem.c:136:5: 
      134.       }
      135.   #else
      136. >     (void)file;
      137.       (void)line;
      138.       ret = malloc(num);

crypto/mem.c:137:5: 
      135.   #else
      136.       (void)file;
      137. >     (void)line;
      138.       ret = malloc(num);
      139.   #endif

crypto/mem.c:138:5: 
      136.       (void)file;
      137.       (void)line;
      138. >     ret = malloc(num);
      139.   #endif
      140.   

crypto/mem.c:153:5: 
      151.   #endif
      152.   
      153. >     return ret;
      154.   }
      155.   

crypto/mem.c:154:1: return from a call to CRYPTO_malloc
      152.   
      153.       return ret;
      154. > }
      155.   
      156.   void *CRYPTO_zalloc(size_t num, const char *file, int line)

crypto/mem.c:160:9: Taking true branch
    158.       void *ret = CRYPTO_malloc(num, file, line);
    159.   
    160.       if (ret != NULL)
                   ^
    161.           memset(ret, 0, num);
    162.       return ret;

crypto/mem.c:161:9: 
    159.   
    160.       if (ret != NULL)
    161. >         memset(ret, 0, num);
    162.       return ret;
    163.   }

crypto/mem.c:162:5: 
    160.       if (ret != NULL)
    161.           memset(ret, 0, num);
    162. >     return ret;
    163.   }
    164.   

crypto/mem.c:163:1: return from a call to CRYPTO_zalloc
    161.           memset(ret, 0, num);
    162.       return ret;
    163. > }
    164.   
    165.   void *CRYPTO_realloc(void *str, size_t num, const char *file, int line)

crypto/bn/bn_lib.c:280:9: Taking false branch
  278.       BIGNUM *ret;
  279.   
  280.       if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
                 ^
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
  282.           return (NULL);

crypto/bn/bn_lib.c:284:5: 
  282.           return (NULL);
  283.       }
  284. >     ret->flags = BN_FLG_MALLOCED;
  285.       bn_check_top(ret);
  286.       return (ret);

crypto/bn/bn_lib.c:286:5: 
  284.       ret->flags = BN_FLG_MALLOCED;
  285.       bn_check_top(ret);
  286. >     return (ret);
  287.   }
  288.   

crypto/bn/bn_lib.c:287:1: return from a call to BN_new
  285.       bn_check_top(ret);
  286.       return (ret);
  287. > }
  288.   
  289.    BIGNUM *BN_secure_new(void)

test/bntest.c:983:5: 
981.       b = BN_new();
982.       c = BN_new();
983. >     d = BN_new();
984.       e = BN_new();
985.   

crypto/bn/bn_lib.c:276:1: start of procedure BN_new()
  274.   }
  275.   
  276. > BIGNUM *BN_new(void)
  277.   {
  278.       BIGNUM *ret;

crypto/bn/bn_lib.c:280:9: 
  278.       BIGNUM *ret;
  279.   
  280. >     if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
  282.           return (NULL);

crypto/mem.c:156:1: start of procedure CRYPTO_zalloc()
    154.   }
    155.   
    156. > void *CRYPTO_zalloc(size_t num, const char *file, int line)
    157.   {
    158.       void *ret = CRYPTO_malloc(num, file, line);

crypto/mem.c:158:5: 
    156.   void *CRYPTO_zalloc(size_t num, const char *file, int line)
    157.   {
    158. >     void *ret = CRYPTO_malloc(num, file, line);
    159.   
    160.       if (ret != NULL)

crypto/mem.c:119:1: start of procedure CRYPTO_malloc()
      117.   }
      118.   
      119. > void *CRYPTO_malloc(size_t num, const char *file, int line)
      120.   {
      121.       void *ret = NULL;

crypto/mem.c:121:5: 
      119.   void *CRYPTO_malloc(size_t num, const char *file, int line)
      120.   {
      121. >     void *ret = NULL;
      122.   
      123.       if (num <= 0)

crypto/mem.c:123:9: Taking false branch
      121.       void *ret = NULL;
      122.   
      123.       if (num <= 0)
                     ^
      124.           return NULL;
      125.   

crypto/mem.c:126:5: 
      124.           return NULL;
      125.   
      126. >     allow_customize = 0;
      127.   #ifndef OPENSSL_NO_CRYPTO_MDEBUG
      128.       if (call_malloc_debug) {

crypto/mem.c:136:5: 
      134.       }
      135.   #else
      136. >     (void)file;
      137.       (void)line;
      138.       ret = malloc(num);

crypto/mem.c:137:5: 
      135.   #else
      136.       (void)file;
      137. >     (void)line;
      138.       ret = malloc(num);
      139.   #endif

crypto/mem.c:138:5: 
      136.       (void)file;
      137.       (void)line;
      138. >     ret = malloc(num);
      139.   #endif
      140.   

crypto/mem.c:153:5: 
      151.   #endif
      152.   
      153. >     return ret;
      154.   }
      155.   

crypto/mem.c:154:1: return from a call to CRYPTO_malloc
      152.   
      153.       return ret;
      154. > }
      155.   
      156.   void *CRYPTO_zalloc(size_t num, const char *file, int line)

crypto/mem.c:160:9: Taking true branch
    158.       void *ret = CRYPTO_malloc(num, file, line);
    159.   
    160.       if (ret != NULL)
                   ^
    161.           memset(ret, 0, num);
    162.       return ret;

crypto/mem.c:161:9: 
    159.   
    160.       if (ret != NULL)
    161. >         memset(ret, 0, num);
    162.       return ret;
    163.   }

crypto/mem.c:162:5: 
    160.       if (ret != NULL)
    161.           memset(ret, 0, num);
    162. >     return ret;
    163.   }
    164.   

crypto/mem.c:163:1: return from a call to CRYPTO_zalloc
    161.           memset(ret, 0, num);
    162.       return ret;
    163. > }
    164.   
    165.   void *CRYPTO_realloc(void *str, size_t num, const char *file, int line)

crypto/bn/bn_lib.c:280:9: Taking false branch
  278.       BIGNUM *ret;
  279.   
  280.       if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
                 ^
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
  282.           return (NULL);

crypto/bn/bn_lib.c:284:5: 
  282.           return (NULL);
  283.       }
  284. >     ret->flags = BN_FLG_MALLOCED;
  285.       bn_check_top(ret);
  286.       return (ret);

crypto/bn/bn_lib.c:286:5: 
  284.       ret->flags = BN_FLG_MALLOCED;
  285.       bn_check_top(ret);
  286. >     return (ret);
  287.   }
  288.   

crypto/bn/bn_lib.c:287:1: return from a call to BN_new
  285.       bn_check_top(ret);
  286.       return (ret);
  287. > }
  288.   
  289.    BIGNUM *BN_secure_new(void)

test/bntest.c:984:5: 
982.       c = BN_new();
983.       d = BN_new();
984. >     e = BN_new();
985.   
986.       BN_one(a);

crypto/bn/bn_lib.c:276:1: start of procedure BN_new()
  274.   }
  275.   
  276. > BIGNUM *BN_new(void)
  277.   {
  278.       BIGNUM *ret;

crypto/bn/bn_lib.c:280:9: 
  278.       BIGNUM *ret;
  279.   
  280. >     if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
  282.           return (NULL);

crypto/mem.c:156:1: start of procedure CRYPTO_zalloc()
    154.   }
    155.   
    156. > void *CRYPTO_zalloc(size_t num, const char *file, int line)
    157.   {
    158.       void *ret = CRYPTO_malloc(num, file, line);

crypto/mem.c:158:5: 
    156.   void *CRYPTO_zalloc(size_t num, const char *file, int line)
    157.   {
    158. >     void *ret = CRYPTO_malloc(num, file, line);
    159.   
    160.       if (ret != NULL)

crypto/mem.c:119:1: start of procedure CRYPTO_malloc()
      117.   }
      118.   
      119. > void *CRYPTO_malloc(size_t num, const char *file, int line)
      120.   {
      121.       void *ret = NULL;

crypto/mem.c:121:5: 
      119.   void *CRYPTO_malloc(size_t num, const char *file, int line)
      120.   {
      121. >     void *ret = NULL;
      122.   
      123.       if (num <= 0)

crypto/mem.c:123:9: Taking false branch
      121.       void *ret = NULL;
      122.   
      123.       if (num <= 0)
                     ^
      124.           return NULL;
      125.   

crypto/mem.c:126:5: 
      124.           return NULL;
      125.   
      126. >     allow_customize = 0;
      127.   #ifndef OPENSSL_NO_CRYPTO_MDEBUG
      128.       if (call_malloc_debug) {

crypto/mem.c:136:5: 
      134.       }
      135.   #else
      136. >     (void)file;
      137.       (void)line;
      138.       ret = malloc(num);

crypto/mem.c:137:5: 
      135.   #else
      136.       (void)file;
      137. >     (void)line;
      138.       ret = malloc(num);
      139.   #endif

crypto/mem.c:138:5: 
      136.       (void)file;
      137.       (void)line;
      138. >     ret = malloc(num);
      139.   #endif
      140.   

crypto/mem.c:153:5: 
      151.   #endif
      152.   
      153. >     return ret;
      154.   }
      155.   

crypto/mem.c:154:1: return from a call to CRYPTO_malloc
      152.   
      153.       return ret;
      154. > }
      155.   
      156.   void *CRYPTO_zalloc(size_t num, const char *file, int line)

crypto/mem.c:160:9: Taking true branch
    158.       void *ret = CRYPTO_malloc(num, file, line);
    159.   
    160.       if (ret != NULL)
                   ^
    161.           memset(ret, 0, num);
    162.       return ret;

crypto/mem.c:161:9: 
    159.   
    160.       if (ret != NULL)
    161. >         memset(ret, 0, num);
    162.       return ret;
    163.   }

crypto/mem.c:162:5: 
    160.       if (ret != NULL)
    161.           memset(ret, 0, num);
    162. >     return ret;
    163.   }
    164.   

crypto/mem.c:163:1: return from a call to CRYPTO_zalloc
    161.           memset(ret, 0, num);
    162.       return ret;
    163. > }
    164.   
    165.   void *CRYPTO_realloc(void *str, size_t num, const char *file, int line)

crypto/bn/bn_lib.c:280:9: Taking false branch
  278.       BIGNUM *ret;
  279.   
  280.       if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
                 ^
  281.           BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
  282.           return (NULL);

crypto/bn/bn_lib.c:284:5: 
  282.           return (NULL);
  283.       }
  284. >     ret->flags = BN_FLG_MALLOCED;
  285.       bn_check_top(ret);
  286.       return (ret);

crypto/bn/bn_lib.c:286:5: 
  284.       ret->flags = BN_FLG_MALLOCED;
  285.       bn_check_top(ret);
  286. >     return (ret);
  287.   }
  288.   

crypto/bn/bn_lib.c:287:1: return from a call to BN_new
  285.       bn_check_top(ret);
  286.       return (ret);
  287. > }
  288.   
  289.    BIGNUM *BN_secure_new(void)

test/bntest.c:986:5: 
984.       e = BN_new();
985.   
986. >     BN_one(a);
987.       BN_one(b);
988.       BN_zero(c);

crypto/bn/bn_lib.c:520:1: start of procedure BN_set_word()
  518.   }
  519.   
  520. > int BN_set_word(BIGNUM *a, BN_ULONG w)
  521.   {
  522.       bn_check_top(a);

crypto/bn/bn_lib.c:523:9: 
  521.   {
  522.       bn_check_top(a);
  523. >     if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)
  524.           return (0);
  525.       a->neg = 0;

int test_mod_exp(BIO *bp, BN_CTX *ctx)
{
    BIGNUM *a, *b, *c, *d, *e;
    int i;
    a = BN_new();
    b = BN_new();
    c = BN_new();
    d = BN_new();
    e = BN_new();
    BN_one(a);
    BN_one(b);
    BN_zero(c);
    if (BN_mod_exp(d, a, b, c, ctx)) {
        fprintf(stderr, "BN_mod_exp with zero modulus succeeded!\n");
        return 0;
    }
    BN_bntest_rand(c, 30, 0, 1);
    for (i = 0; i < num2; i++) {
        BN_bntest_rand(a, 20 + i * 5, 0, 0);
        BN_bntest_rand(b, 2 + i, 0, 0);
        if (!BN_mod_exp(d, a, b, c, ctx))
            return (0);
        if (bp != NULL) {
            if (!results) {
                BN_print(bp, a);
                BIO_puts(bp, " ^ ");
                BN_print(bp, b);
                BIO_puts(bp, " % ");
                BN_print(bp, c);
                BIO_puts(bp, " - ");
            }
            BN_print(bp, d);
            BIO_puts(bp, "\n");
        }
        BN_exp(e, a, b, ctx);
        BN_sub(e, e, d);
        BN_div(a, b, e, c, ctx);
        if (!BN_is_zero(b)) {
            fprintf(stderr, "Modulo exponentiation test failed!\n");
            return 0;
        }
    }
    BN_hex2bn(&a, "050505050505");
    BN_hex2bn(&b, "02");
    BN_hex2bn(&c,
        "4141414141414141414141274141414141414141414141414141414141414141"
        "4141414141414141414141414141414141414141414141414141414141414141"
        "4141414141414141414141800000000000000000000000000000000000000000"
        "0000000000000000000000000000000000000000000000000000000000000000"
        "0000000000000000000000000000000000000000000000000000000000000000"
        "0000000000000000000000000000000000000000000000000000000001");
    BN_mod_exp(d, a, b, c, ctx);
    BN_mul(e, a, a, ctx);
    if (BN_cmp(d, e)) {
        fprintf(stderr, "BN_mod_exp and BN_mul produce different results!\n");
        return 0;
    }
    BN_free(a);
    BN_free(b);
    BN_free(c);
    BN_free(d);
    BN_free(e);
    return (1);
}
['int test_mod_exp(BIO *bp, BN_CTX *ctx)\n{\n    BIGNUM *a, *b, *c, *d, *e;\n    int i;\n    a = BN_new();\n    b = BN_new();\n    c = BN_new();\n    d = BN_new();\n    e = BN_new();\n    BN_one(a);\n    BN_one(b);\n    BN_zero(c);\n    if (BN_mod_exp(d, a, b, c, ctx)) {\n        fprintf(stderr, "BN_mod_exp with zero modulus succeeded!\\n");\n        return 0;\n    }\n    BN_bntest_rand(c, 30, 0, 1);\n    for (i = 0; i < num2; i++) {\n        BN_bntest_rand(a, 20 + i * 5, 0, 0);\n        BN_bntest_rand(b, 2 + i, 0, 0);\n        if (!BN_mod_exp(d, a, b, c, ctx))\n            return (0);\n        if (bp != NULL) {\n            if (!results) {\n                BN_print(bp, a);\n                BIO_puts(bp, " ^ ");\n                BN_print(bp, b);\n                BIO_puts(bp, " % ");\n                BN_print(bp, c);\n                BIO_puts(bp, " - ");\n            }\n            BN_print(bp, d);\n            BIO_puts(bp, "\\n");\n        }\n        BN_exp(e, a, b, ctx);\n        BN_sub(e, e, d);\n        BN_div(a, b, e, c, ctx);\n        if (!BN_is_zero(b)) {\n            fprintf(stderr, "Modulo exponentiation test failed!\\n");\n            return 0;\n        }\n    }\n    BN_hex2bn(&a, "050505050505");\n    BN_hex2bn(&b, "02");\n    BN_hex2bn(&c,\n        "4141414141414141414141274141414141414141414141414141414141414141"\n        "4141414141414141414141414141414141414141414141414141414141414141"\n        "4141414141414141414141800000000000000000000000000000000000000000"\n        "0000000000000000000000000000000000000000000000000000000000000000"\n        "0000000000000000000000000000000000000000000000000000000000000000"\n        "0000000000000000000000000000000000000000000000000000000001");\n    BN_mod_exp(d, a, b, c, ctx);\n    BN_mul(e, a, a, ctx);\n    if (BN_cmp(d, e)) {\n        fprintf(stderr, "BN_mod_exp and BN_mul produce different results!\\n");\n        return 0;\n    }\n    BN_free(a);\n    BN_free(b);\n    BN_free(c);\n    BN_free(d);\n    BN_free(e);\n    return (1);\n}', 'BIGNUM *BN_new(void)\n{\n    BIGNUM *ret;\n    if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {\n        BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);\n        return (NULL);\n    }\n    ret->flags = BN_FLG_MALLOCED;\n    bn_check_top(ret);\n    return (ret);\n}', 'void *CRYPTO_zalloc(size_t num, const char *file, int line)\n{\n    void *ret = CRYPTO_malloc(num, file, line);\n    if (ret != NULL)\n        memset(ret, 0, num);\n    return ret;\n}', 'void *CRYPTO_malloc(size_t num, const char *file, int line)\n{\n    void *ret = NULL;\n    if (num <= 0)\n        return NULL;\n    allow_customize = 0;\n#ifndef OPENSSL_NO_CRYPTO_MDEBUG\n    if (call_malloc_debug) {\n        CRYPTO_mem_debug_malloc(NULL, num, 0, file, line);\n        ret = malloc(num);\n        CRYPTO_mem_debug_malloc(ret, num, 1, file, line);\n    } else {\n        ret = malloc(num);\n    }\n#else\n    (void)file;\n    (void)line;\n    ret = malloc(num);\n#endif\n#ifndef OPENSSL_CPUID_OBJ\n    if (ret && (num > 2048)) {\n        extern unsigned char cleanse_ctr;\n        ((unsigned char *)ret)[0] = cleanse_ctr;\n    }\n#endif\n    return ret;\n}', 'int BN_set_word(BIGNUM *a, BN_ULONG w)\n{\n    bn_check_top(a);\n    if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)\n        return (0);\n    a->neg = 0;\n    a->d[0] = w;\n    a->top = (w ? 1 : 0);\n    bn_check_top(a);\n    return (1);\n}']