test/exptest.c:171: error: BUFFER_OVERRUN_L3
  Offset added: [8, +oo] Size: [0, 536870848] by call to `BN_mod_exp_recp`.
Showing all 12 steps of the trace


test/exptest.c:167:5: Call
165.       BN_rand(m, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD);
166.   
167.       BN_mod(a, a, m, ctx);
           ^
168.       BN_mod(b, b, m, ctx);
169.   

crypto/bn/bn_div.c:140:1: Parameter `rm->top`
  138.    * If 'dv' or 'rm' is NULL, the respective value is not returned.
  139.    */
  140. > int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
  141.              BN_CTX *ctx)
  142.   {

test/exptest.c:171:13: Call
169.   
170.       if (!TEST_true(BN_mod_exp_mont(r_mont, a, b, m, ctx, NULL))
171.           || !TEST_true(BN_mod_exp_recp(r_recp, a, b, m, ctx))
                   ^
172.           || !TEST_true(BN_mod_exp_simple(r_simple, a, b, m, ctx))
173.           || !TEST_true(BN_mod_exp_mont_consttime(r_mont_const, a, b, m, ctx, NULL)))

crypto/bn/bn_exp.c:161:1: Parameter `m->top`
  159.   }
  160.   
  161. > int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
  162.                       const BIGNUM *m, BN_CTX *ctx)
  163.   {

crypto/bn/bn_exp.c:198:14: Call
  196.       if (m->neg) {
  197.           /* ignore sign of 'm' */
  198.           if (!BN_copy(aa, m))
                      ^
  199.               goto err;
  200.           aa->neg = 0;

crypto/bn/bn_lib.c:323:1: <Offset trace>
321.   }
322.   
323. > BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
324.   {
325.       bn_check_top(b);

crypto/bn/bn_lib.c:323:1: Parameter `b->top`
    321.   }
    322.   
    323. > BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
    324.   {
    325.       bn_check_top(b);

crypto/bn/bn_lib.c:323:1: <Length trace>
321.   }
322.   
323. > BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
324.   {
325.       bn_check_top(b);

crypto/bn/bn_lib.c:323:1: Parameter `*a->d`
    321.   }
    322.   
    323. > BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
    324.   {
    325.       bn_check_top(b);

crypto/bn/bn_lib.c:329:9: Call
    327.       if (a == b)
    328.           return a;
    329.       if (bn_wexpand(a, b->top) == NULL)
                   ^
    330.           return NULL;
    331.   

crypto/bn/bn_lib.c:948:1: Parameter `*a->d`
      946.   }
      947.   
      948. > BIGNUM *bn_wexpand(BIGNUM *a, int words)
      949.   {
      950.       return (words <= a->dmax) ? a : bn_expand2(a, words);

crypto/bn/bn_lib.c:333:9: Array access: Offset added: [8, +oo] Size: [0, 536870848] by call to `BN_mod_exp_recp` 
    331.   
    332.       if (b->top > 0)
    333.           memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
                   ^
    334.   
    335.       a->top = b->top;

BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
{
    bn_check_top(b);
    if (a == b)
        return a;
    if (bn_wexpand(a, b->top) == NULL)
        return NULL;
    if (b->top > 0)
        memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
    a->top = b->top;
    a->neg = b->neg;
    bn_check_top(a);
    return a;
}
['static int test_mod_exp(int round)\n{\n    BN_CTX *ctx;\n    unsigned char c;\n    int ret = 0;\n    BIGNUM *r_mont = NULL;\n    BIGNUM *r_mont_const = NULL;\n    BIGNUM *r_recp = NULL;\n    BIGNUM *r_simple = NULL;\n    BIGNUM *a = NULL;\n    BIGNUM *b = NULL;\n    BIGNUM *m = NULL;\n    if (!TEST_ptr(ctx = BN_CTX_new()))\n        goto err;\n    if (!TEST_ptr(r_mont = BN_new())\n        || !TEST_ptr(r_mont_const = BN_new())\n        || !TEST_ptr(r_recp = BN_new())\n        || !TEST_ptr(r_simple = BN_new())\n        || !TEST_ptr(a = BN_new())\n        || !TEST_ptr(b = BN_new())\n        || !TEST_ptr(m = BN_new()))\n        goto err;\n    RAND_bytes(&c, 1);\n    c = (c % BN_BITS) - BN_BITS2;\n    BN_rand(a, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);\n    RAND_bytes(&c, 1);\n    c = (c % BN_BITS) - BN_BITS2;\n    BN_rand(b, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);\n    RAND_bytes(&c, 1);\n    c = (c % BN_BITS) - BN_BITS2;\n    BN_rand(m, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD);\n    BN_mod(a, a, m, ctx);\n    BN_mod(b, b, m, ctx);\n    if (!TEST_true(BN_mod_exp_mont(r_mont, a, b, m, ctx, NULL))\n        || !TEST_true(BN_mod_exp_recp(r_recp, a, b, m, ctx))\n        || !TEST_true(BN_mod_exp_simple(r_simple, a, b, m, ctx))\n        || !TEST_true(BN_mod_exp_mont_consttime(r_mont_const, a, b, m, ctx, NULL)))\n        goto err;\n    if (TEST_int_eq(BN_cmp(r_simple, r_mont), 0)\n        && TEST_int_eq(BN_cmp(r_simple, r_recp), 0)\n        && TEST_int_eq(BN_cmp(r_simple, r_mont_const), 0)) {\n        printf(".");\n        fflush(stdout);\n    } else {\n        if (BN_cmp(r_simple, r_mont) != 0)\n            fprintf(stderr, "simple and mont results differ\\n");\n        if (BN_cmp(r_simple, r_mont_const) != 0)\n            fprintf(stderr, "simple and mont const time results differ\\n");\n        if (BN_cmp(r_simple, r_recp) != 0)\n            fprintf(stderr, "simple and recp results differ\\n");\n        BN_print_var(a);\n        BN_print_var(b);\n        BN_print_var(m);\n        BN_print_var(r_simple);\n        BN_print_var(r_recp);\n        BN_print_var(r_mont);\n        BN_print_var(r_mont_const);\n        goto err;\n    }\n    ret = 1;\n err:\n    BN_free(r_mont);\n    BN_free(r_mont_const);\n    BN_free(r_recp);\n    BN_free(r_simple);\n    BN_free(a);\n    BN_free(b);\n    BN_free(m);\n    BN_CTX_free(ctx);\n    return ret;\n}', 'int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,\n           BN_CTX *ctx)\n{\n    int norm_shift, i, loop;\n    BIGNUM *tmp, wnum, *snum, *sdiv, *res;\n    BN_ULONG *resp, *wnump;\n    BN_ULONG d0, d1;\n    int num_n, div_n;\n    int no_branch = 0;\n    if ((num->top > 0 && num->d[num->top - 1] == 0) ||\n        (divisor->top > 0 && divisor->d[divisor->top - 1] == 0)) {\n        BNerr(BN_F_BN_DIV, BN_R_NOT_INITIALIZED);\n        return 0;\n    }\n    bn_check_top(num);\n    bn_check_top(divisor);\n    if ((BN_get_flags(num, BN_FLG_CONSTTIME) != 0)\n        || (BN_get_flags(divisor, BN_FLG_CONSTTIME) != 0)) {\n        no_branch = 1;\n    }\n    bn_check_top(dv);\n    bn_check_top(rm);\n    if (BN_is_zero(divisor)) {\n        BNerr(BN_F_BN_DIV, BN_R_DIV_BY_ZERO);\n        return (0);\n    }\n    if (!no_branch && BN_ucmp(num, divisor) < 0) {\n        if (rm != NULL) {\n            if (BN_copy(rm, num) == NULL)\n                return (0);\n        }\n        if (dv != NULL)\n            BN_zero(dv);\n        return (1);\n    }\n    BN_CTX_start(ctx);\n    tmp = BN_CTX_get(ctx);\n    snum = BN_CTX_get(ctx);\n    sdiv = BN_CTX_get(ctx);\n    if (dv == NULL)\n        res = BN_CTX_get(ctx);\n    else\n        res = dv;\n    if (sdiv == NULL || res == NULL || tmp == NULL || snum == NULL)\n        goto err;\n    norm_shift = BN_BITS2 - ((BN_num_bits(divisor)) % BN_BITS2);\n    if (!(BN_lshift(sdiv, divisor, norm_shift)))\n        goto err;\n    sdiv->neg = 0;\n    norm_shift += BN_BITS2;\n    if (!(BN_lshift(snum, num, norm_shift)))\n        goto err;\n    snum->neg = 0;\n    if (no_branch) {\n        if (snum->top <= sdiv->top + 1) {\n            if (bn_wexpand(snum, sdiv->top + 2) == NULL)\n                goto err;\n            for (i = snum->top; i < sdiv->top + 2; i++)\n                snum->d[i] = 0;\n            snum->top = sdiv->top + 2;\n        } else {\n            if (bn_wexpand(snum, snum->top + 1) == NULL)\n                goto err;\n            snum->d[snum->top] = 0;\n            snum->top++;\n        }\n    }\n    div_n = sdiv->top;\n    num_n = snum->top;\n    loop = num_n - div_n;\n    wnum.neg = 0;\n    wnum.d = &(snum->d[loop]);\n    wnum.top = div_n;\n    wnum.dmax = snum->dmax - loop;\n    d0 = sdiv->d[div_n - 1];\n    d1 = (div_n == 1) ? 0 : sdiv->d[div_n - 2];\n    wnump = &(snum->d[num_n - 1]);\n    if (!bn_wexpand(res, (loop + 1)))\n        goto err;\n    res->neg = (num->neg ^ divisor->neg);\n    res->top = loop - no_branch;\n    resp = &(res->d[loop - 1]);\n    if (!bn_wexpand(tmp, (div_n + 1)))\n        goto err;\n    if (!no_branch) {\n        if (BN_ucmp(&wnum, sdiv) >= 0) {\n            bn_clear_top2max(&wnum);\n            bn_sub_words(wnum.d, wnum.d, sdiv->d, div_n);\n            *resp = 1;\n        } else\n            res->top--;\n    }\n    resp++;\n    if (res->top == 0)\n        res->neg = 0;\n    else\n        resp--;\n    for (i = 0; i < loop - 1; i++, wnump--) {\n        BN_ULONG q, l0;\n# if defined(BN_DIV3W) && !defined(OPENSSL_NO_ASM)\n        BN_ULONG bn_div_3_words(BN_ULONG *, BN_ULONG, BN_ULONG);\n        q = bn_div_3_words(wnump, d1, d0);\n# else\n        BN_ULONG n0, n1, rem = 0;\n        n0 = wnump[0];\n        n1 = wnump[-1];\n        if (n0 == d0)\n            q = BN_MASK2;\n        else {\n#  ifdef BN_LLONG\n            BN_ULLONG t2;\n#   if defined(BN_LLONG) && defined(BN_DIV2W) && !defined(bn_div_words)\n            q = (BN_ULONG)(((((BN_ULLONG) n0) << BN_BITS2) | n1) / d0);\n#   else\n            q = bn_div_words(n0, n1, d0);\n#   endif\n#   ifndef REMAINDER_IS_ALREADY_CALCULATED\n            rem = (n1 - q * d0) & BN_MASK2;\n#   endif\n            t2 = (BN_ULLONG) d1 *q;\n            for (;;) {\n                if (t2 <= ((((BN_ULLONG) rem) << BN_BITS2) | wnump[-2]))\n                    break;\n                q--;\n                rem += d0;\n                if (rem < d0)\n                    break;\n                t2 -= d1;\n            }\n#  else\n            BN_ULONG t2l, t2h;\n            q = bn_div_words(n0, n1, d0);\n#   ifndef REMAINDER_IS_ALREADY_CALCULATED\n            rem = (n1 - q * d0) & BN_MASK2;\n#   endif\n#   if defined(BN_UMULT_LOHI)\n            BN_UMULT_LOHI(t2l, t2h, d1, q);\n#   elif defined(BN_UMULT_HIGH)\n            t2l = d1 * q;\n            t2h = BN_UMULT_HIGH(d1, q);\n#   else\n            {\n                BN_ULONG ql, qh;\n                t2l = LBITS(d1);\n                t2h = HBITS(d1);\n                ql = LBITS(q);\n                qh = HBITS(q);\n                mul64(t2l, t2h, ql, qh);\n            }\n#   endif\n            for (;;) {\n                if ((t2h < rem) || ((t2h == rem) && (t2l <= wnump[-2])))\n                    break;\n                q--;\n                rem += d0;\n                if (rem < d0)\n                    break;\n                if (t2l < d1)\n                    t2h--;\n                t2l -= d1;\n            }\n#  endif\n        }\n# endif\n        l0 = bn_mul_words(tmp->d, sdiv->d, div_n, q);\n        tmp->d[div_n] = l0;\n        wnum.d--;\n        if (bn_sub_words(wnum.d, wnum.d, tmp->d, div_n + 1)) {\n            q--;\n            if (bn_add_words(wnum.d, wnum.d, sdiv->d, div_n))\n                (*wnump)++;\n        }\n        resp--;\n        *resp = q;\n    }\n    bn_correct_top(snum);\n    if (rm != NULL) {\n        int neg = num->neg;\n        BN_rshift(rm, snum, norm_shift);\n        if (!BN_is_zero(rm))\n            rm->neg = neg;\n        bn_check_top(rm);\n    }\n    if (no_branch)\n        bn_correct_top(res);\n    BN_CTX_end(ctx);\n    return (1);\n err:\n    bn_check_top(rm);\n    BN_CTX_end(ctx);\n    return (0);\n}', 'int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,\n                    const BIGNUM *m, BN_CTX *ctx)\n{\n    int i, j, bits, ret = 0, wstart, wend, window, wvalue;\n    int start = 1;\n    BIGNUM *aa;\n    BIGNUM *val[TABLE_SIZE];\n    BN_RECP_CTX recp;\n    if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0) {\n        BNerr(BN_F_BN_MOD_EXP_RECP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);\n        return 0;\n    }\n    bits = BN_num_bits(p);\n    if (bits == 0) {\n        if (BN_is_one(m)) {\n            ret = 1;\n            BN_zero(r);\n        } else {\n            ret = BN_one(r);\n        }\n        return ret;\n    }\n    BN_CTX_start(ctx);\n    aa = BN_CTX_get(ctx);\n    val[0] = BN_CTX_get(ctx);\n    if (!aa || !val[0])\n        goto err;\n    BN_RECP_CTX_init(&recp);\n    if (m->neg) {\n        if (!BN_copy(aa, m))\n            goto err;\n        aa->neg = 0;\n        if (BN_RECP_CTX_set(&recp, aa, ctx) <= 0)\n            goto err;\n    } else {\n        if (BN_RECP_CTX_set(&recp, m, ctx) <= 0)\n            goto err;\n    }\n    if (!BN_nnmod(val[0], a, m, ctx))\n        goto err;\n    if (BN_is_zero(val[0])) {\n        BN_zero(r);\n        ret = 1;\n        goto err;\n    }\n    window = BN_window_bits_for_exponent_size(bits);\n    if (window > 1) {\n        if (!BN_mod_mul_reciprocal(aa, val[0], val[0], &recp, ctx))\n            goto err;\n        j = 1 << (window - 1);\n        for (i = 1; i < j; i++) {\n            if (((val[i] = BN_CTX_get(ctx)) == NULL) ||\n                !BN_mod_mul_reciprocal(val[i], val[i - 1], aa, &recp, ctx))\n                goto err;\n        }\n    }\n    start = 1;\n    wvalue = 0;\n    wstart = bits - 1;\n    wend = 0;\n    if (!BN_one(r))\n        goto err;\n    for (;;) {\n        if (BN_is_bit_set(p, wstart) == 0) {\n            if (!start)\n                if (!BN_mod_mul_reciprocal(r, r, r, &recp, ctx))\n                    goto err;\n            if (wstart == 0)\n                break;\n            wstart--;\n            continue;\n        }\n        j = wstart;\n        wvalue = 1;\n        wend = 0;\n        for (i = 1; i < window; i++) {\n            if (wstart - i < 0)\n                break;\n            if (BN_is_bit_set(p, wstart - i)) {\n                wvalue <<= (i - wend);\n                wvalue |= 1;\n                wend = i;\n            }\n        }\n        j = wend + 1;\n        if (!start)\n            for (i = 0; i < j; i++) {\n                if (!BN_mod_mul_reciprocal(r, r, r, &recp, ctx))\n                    goto err;\n            }\n        if (!BN_mod_mul_reciprocal(r, r, val[wvalue >> 1], &recp, ctx))\n            goto err;\n        wstart -= wend + 1;\n        wvalue = 0;\n        start = 0;\n        if (wstart < 0)\n            break;\n    }\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    BN_RECP_CTX_free(&recp);\n    bn_check_top(r);\n    return (ret);\n}', 'BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)\n{\n    bn_check_top(b);\n    if (a == b)\n        return a;\n    if (bn_wexpand(a, b->top) == NULL)\n        return NULL;\n    if (b->top > 0)\n        memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);\n    a->top = b->top;\n    a->neg = b->neg;\n    bn_check_top(a);\n    return a;\n}', 'BIGNUM *bn_wexpand(BIGNUM *a, int words)\n{\n    return (words <= a->dmax) ? a : bn_expand2(a, words);\n}']