crypto/bn/bn_sqrt.c:98: error: INTEGER_OVERFLOW_L2
  ([0, +oo] - 1):unsigned32 by call to `BN_mod_exp`.
Showing all 27 steps of the trace


crypto/bn/bn_sqrt.c:75:10: Call
73.   
74.       /* A = a mod p */
75.       if (!BN_nnmod(A, a, p, ctx))
               ^
76.           goto end;
77.   

crypto/bn/bn_mod.c:20:11: Call
  18.        */
  19.   
  20.       if (!(BN_mod(r, m, d, ctx)))
                  ^
  21.           return 0;
  22.       if (!r->neg)

crypto/bn/bn_div.c:140:1: Parameter `ctx->pool.used`
    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.   {

crypto/bn/bn_sqrt.c:98:14: Call
96.           if (!BN_add_word(q, 1))
97.               goto end;
98.           if (!BN_mod_exp(ret, A, q, p, ctx))
                    ^
99.               goto end;
100.           err = 0;

crypto/bn/bn_exp.c:88:1: Parameter `ctx->pool.used`
  86.   }
  87.   
  88. > int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m,
  89.                  BN_CTX *ctx)
  90.   {

crypto/bn/bn_exp.c:146:15: Call
  144.   #ifdef RECP_MUL_MOD
  145.       {
  146.           ret = BN_mod_exp_recp(r, a, p, m, ctx);
                       ^
  147.       }
  148.   #else

crypto/bn/bn_exp.c:158:1: Parameter `ctx->pool.used`
    156.   }
    157.   
    158. > int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
    159.                       const BIGNUM *m, BN_CTX *ctx)
    160.   {

crypto/bn/bn_exp.c:187:10: Call
    185.   
    186.       BN_CTX_start(ctx);
    187.       aa = BN_CTX_get(ctx);
                    ^
    188.       val[0] = BN_CTX_get(ctx);
    189.       if (val[0] == NULL)

crypto/bn/bn_ctx.c:212:1: Parameter `ctx->pool.used`
      210.   }
      211.   
      212. > BIGNUM *BN_CTX_get(BN_CTX *ctx)
      213.   {
      214.       BIGNUM *ret;

crypto/bn/bn_exp.c:188:14: Call
    186.       BN_CTX_start(ctx);
    187.       aa = BN_CTX_get(ctx);
    188.       val[0] = BN_CTX_get(ctx);
                        ^
    189.       if (val[0] == NULL)
    190.           goto err;

crypto/bn/bn_ctx.c:212:1: Parameter `ctx->pool.used`
      210.   }
      211.   
      212. > BIGNUM *BN_CTX_get(BN_CTX *ctx)
      213.   {
      214.       BIGNUM *ret;

crypto/bn/bn_exp.c:205:10: Call
    203.       }
    204.   
    205.       if (!BN_nnmod(val[0], a, m, ctx))
                    ^
    206.           goto err;               /* 1 */
    207.       if (BN_is_zero(val[0])) {

crypto/bn/bn_mod.c:13:1: Parameter `ctx->pool.used`
      11.   #include "bn_lcl.h"
      12.   
      13. > int BN_nnmod(BIGNUM *r, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx)
      14.   {
      15.       /*

crypto/bn/bn_mod.c:20:11: Call
      18.        */
      19.   
      20.       if (!(BN_mod(r, m, d, ctx)))
                      ^
      21.           return 0;
      22.       if (!r->neg)

crypto/bn/bn_div.c:140:1: Parameter `ctx->pool.used`
        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.   {

crypto/bn/bn_div.c:195:11: Call
        193.       BN_CTX_start(ctx);
        194.       res = (dv == NULL) ? BN_CTX_get(ctx) : dv;
        195.       tmp = BN_CTX_get(ctx);
                         ^
        196.       snum = BN_CTX_get(ctx);
        197.       sdiv = BN_CTX_get(ctx);

crypto/bn/bn_ctx.c:212:1: Parameter `ctx->pool.used`
          210.   }
          211.   
          212. > BIGNUM *BN_CTX_get(BN_CTX *ctx)
          213.   {
          214.       BIGNUM *ret;

crypto/bn/bn_div.c:196:12: Call
        194.       res = (dv == NULL) ? BN_CTX_get(ctx) : dv;
        195.       tmp = BN_CTX_get(ctx);
        196.       snum = BN_CTX_get(ctx);
                          ^
        197.       sdiv = BN_CTX_get(ctx);
        198.       if (sdiv == NULL)

crypto/bn/bn_ctx.c:212:1: Parameter `ctx->pool.used`
          210.   }
          211.   
          212. > BIGNUM *BN_CTX_get(BN_CTX *ctx)
          213.   {
          214.       BIGNUM *ret;

crypto/bn/bn_div.c:197:12: Call
        195.       tmp = BN_CTX_get(ctx);
        196.       snum = BN_CTX_get(ctx);
        197.       sdiv = BN_CTX_get(ctx);
                          ^
        198.       if (sdiv == NULL)
        199.           goto err;

crypto/bn/bn_ctx.c:212:1: Parameter `ctx->pool.used`
          210.   }
          211.   
          212. > BIGNUM *BN_CTX_get(BN_CTX *ctx)
          213.   {
          214.       BIGNUM *ret;

crypto/bn/bn_div.c:413:5: Call
        411.       if (no_branch)
        412.           bn_correct_top(res);
        413.       BN_CTX_end(ctx);
                   ^
        414.       return (1);
        415.    err:

crypto/bn/bn_ctx.c:195:1: Parameter `ctx->pool.used`
          193.   }
          194.   
          195. > void BN_CTX_end(BN_CTX *ctx)
          196.   {
          197.       CTXDBG_ENTRY("BN_CTX_end", ctx);

crypto/bn/bn_ctx.c:204:13: Call
          202.           /* Does this stack frame have anything to release? */
          203.           if (fp < ctx->used)
          204.               BN_POOL_release(&ctx->pool, ctx->used - fp);
                             ^
          205.           ctx->used = fp;
          206.           /* Unjam "too_many" in case "get" had failed */

crypto/bn/bn_ctx.c:340:1: <LHS trace>
338.   }
339.   
340. > static void BN_POOL_release(BN_POOL *p, unsigned int num)
341.   {
342.       unsigned int offset = (p->used - 1) % BN_CTX_POOL_SIZE;

crypto/bn/bn_ctx.c:340:1: Parameter `p->used`
            338.   }
            339.   
            340. > static void BN_POOL_release(BN_POOL *p, unsigned int num)
            341.   {
            342.       unsigned int offset = (p->used - 1) % BN_CTX_POOL_SIZE;

crypto/bn/bn_ctx.c:342:5: Binary operation: ([0, +oo] - 1):unsigned32 by call to `BN_mod_exp` 
            340.   static void BN_POOL_release(BN_POOL *p, unsigned int num)
            341.   {
            342.       unsigned int offset = (p->used - 1) % BN_CTX_POOL_SIZE;
                       ^
            343.   
            344.       p->used -= num;

static void BN_POOL_release(BN_POOL *p, unsigned int num)
{
    unsigned int offset = (p->used - 1) % BN_CTX_POOL_SIZE;
    p->used -= num;
    while (num--) {
        bn_check_top(p->current->vals + offset);
        if (offset == 0) {
            offset = BN_CTX_POOL_SIZE - 1;
            p->current = p->current->prev;
        } else
            offset--;
    }
}
['BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)\n{\n    BIGNUM *ret = in;\n    int err = 1;\n    int r;\n    BIGNUM *A, *b, *q, *t, *x, *y;\n    int e, i, j;\n    if (!BN_is_odd(p) || BN_abs_is_word(p, 1)) {\n        if (BN_abs_is_word(p, 2)) {\n            if (ret == NULL)\n                ret = BN_new();\n            if (ret == NULL)\n                goto end;\n            if (!BN_set_word(ret, BN_is_bit_set(a, 0))) {\n                if (ret != in)\n                    BN_free(ret);\n                return NULL;\n            }\n            bn_check_top(ret);\n            return ret;\n        }\n        BNerr(BN_F_BN_MOD_SQRT, BN_R_P_IS_NOT_PRIME);\n        return (NULL);\n    }\n    if (BN_is_zero(a) || BN_is_one(a)) {\n        if (ret == NULL)\n            ret = BN_new();\n        if (ret == NULL)\n            goto end;\n        if (!BN_set_word(ret, BN_is_one(a))) {\n            if (ret != in)\n                BN_free(ret);\n            return NULL;\n        }\n        bn_check_top(ret);\n        return ret;\n    }\n    BN_CTX_start(ctx);\n    A = BN_CTX_get(ctx);\n    b = BN_CTX_get(ctx);\n    q = BN_CTX_get(ctx);\n    t = BN_CTX_get(ctx);\n    x = BN_CTX_get(ctx);\n    y = BN_CTX_get(ctx);\n    if (y == NULL)\n        goto end;\n    if (ret == NULL)\n        ret = BN_new();\n    if (ret == NULL)\n        goto end;\n    if (!BN_nnmod(A, a, p, ctx))\n        goto end;\n    e = 1;\n    while (!BN_is_bit_set(p, e))\n        e++;\n    if (e == 1) {\n        if (!BN_rshift(q, p, 2))\n            goto end;\n        q->neg = 0;\n        if (!BN_add_word(q, 1))\n            goto end;\n        if (!BN_mod_exp(ret, A, q, p, ctx))\n            goto end;\n        err = 0;\n        goto vrfy;\n    }\n    if (e == 2) {\n        if (!BN_mod_lshift1_quick(t, A, p))\n            goto end;\n        if (!BN_rshift(q, p, 3))\n            goto end;\n        q->neg = 0;\n        if (!BN_mod_exp(b, t, q, p, ctx))\n            goto end;\n        if (!BN_mod_sqr(y, b, p, ctx))\n            goto end;\n        if (!BN_mod_mul(t, t, y, p, ctx))\n            goto end;\n        if (!BN_sub_word(t, 1))\n            goto end;\n        if (!BN_mod_mul(x, A, b, p, ctx))\n            goto end;\n        if (!BN_mod_mul(x, x, t, p, ctx))\n            goto end;\n        if (!BN_copy(ret, x))\n            goto end;\n        err = 0;\n        goto vrfy;\n    }\n    if (!BN_copy(q, p))\n        goto end;\n    q->neg = 0;\n    i = 2;\n    do {\n        if (i < 22) {\n            if (!BN_set_word(y, i))\n                goto end;\n        } else {\n            if (!BN_pseudo_rand(y, BN_num_bits(p), 0, 0))\n                goto end;\n            if (BN_ucmp(y, p) >= 0) {\n                if (!(p->neg ? BN_add : BN_sub) (y, y, p))\n                    goto end;\n            }\n            if (BN_is_zero(y))\n                if (!BN_set_word(y, i))\n                    goto end;\n        }\n        r = BN_kronecker(y, q, ctx);\n        if (r < -1)\n            goto end;\n        if (r == 0) {\n            BNerr(BN_F_BN_MOD_SQRT, BN_R_P_IS_NOT_PRIME);\n            goto end;\n        }\n    }\n    while (r == 1 && ++i < 82);\n    if (r != -1) {\n        BNerr(BN_F_BN_MOD_SQRT, BN_R_TOO_MANY_ITERATIONS);\n        goto end;\n    }\n    if (!BN_rshift(q, q, e))\n        goto end;\n    if (!BN_mod_exp(y, y, q, p, ctx))\n        goto end;\n    if (BN_is_one(y)) {\n        BNerr(BN_F_BN_MOD_SQRT, BN_R_P_IS_NOT_PRIME);\n        goto end;\n    }\n    if (!BN_rshift1(t, q))\n        goto end;\n    if (BN_is_zero(t)) {\n        if (!BN_nnmod(t, A, p, ctx))\n            goto end;\n        if (BN_is_zero(t)) {\n            BN_zero(ret);\n            err = 0;\n            goto end;\n        } else if (!BN_one(x))\n            goto end;\n    } else {\n        if (!BN_mod_exp(x, A, t, p, ctx))\n            goto end;\n        if (BN_is_zero(x)) {\n            BN_zero(ret);\n            err = 0;\n            goto end;\n        }\n    }\n    if (!BN_mod_sqr(b, x, p, ctx))\n        goto end;\n    if (!BN_mod_mul(b, b, A, p, ctx))\n        goto end;\n    if (!BN_mod_mul(x, x, A, p, ctx))\n        goto end;\n    while (1) {\n        if (BN_is_one(b)) {\n            if (!BN_copy(ret, x))\n                goto end;\n            err = 0;\n            goto vrfy;\n        }\n        i = 1;\n        if (!BN_mod_sqr(t, b, p, ctx))\n            goto end;\n        while (!BN_is_one(t)) {\n            i++;\n            if (i == e) {\n                BNerr(BN_F_BN_MOD_SQRT, BN_R_NOT_A_SQUARE);\n                goto end;\n            }\n            if (!BN_mod_mul(t, t, t, p, ctx))\n                goto end;\n        }\n        if (!BN_copy(t, y))\n            goto end;\n        for (j = e - i - 1; j > 0; j--) {\n            if (!BN_mod_sqr(t, t, p, ctx))\n                goto end;\n        }\n        if (!BN_mod_mul(y, t, t, p, ctx))\n            goto end;\n        if (!BN_mod_mul(x, x, t, p, ctx))\n            goto end;\n        if (!BN_mod_mul(b, b, y, p, ctx))\n            goto end;\n        e = i;\n    }\n vrfy:\n    if (!err) {\n        if (!BN_mod_sqr(x, ret, p, ctx))\n            err = 1;\n        if (!err && 0 != BN_cmp(x, A)) {\n            BNerr(BN_F_BN_MOD_SQRT, BN_R_NOT_A_SQUARE);\n            err = 1;\n        }\n    }\n end:\n    if (err) {\n        if (ret != in)\n            BN_clear_free(ret);\n        ret = NULL;\n    }\n    BN_CTX_end(ctx);\n    bn_check_top(ret);\n    return ret;\n}', 'int BN_nnmod(BIGNUM *r, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx)\n{\n    if (!(BN_mod(r, m, d, ctx)))\n        return 0;\n    if (!r->neg)\n        return 1;\n    return (d->neg ? BN_sub : BN_add) (r, r, d);\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    res = (dv == NULL) ? BN_CTX_get(ctx) : dv;\n    tmp = BN_CTX_get(ctx);\n    snum = BN_CTX_get(ctx);\n    sdiv = BN_CTX_get(ctx);\n    if (sdiv == 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(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m,\n               BN_CTX *ctx)\n{\n    int ret;\n    bn_check_top(a);\n    bn_check_top(p);\n    bn_check_top(m);\n#define MONT_MUL_MOD\n#define MONT_EXP_WORD\n#define RECP_MUL_MOD\n#ifdef MONT_MUL_MOD\n    if (BN_is_odd(m)) {\n# ifdef MONT_EXP_WORD\n        if (a->top == 1 && !a->neg\n            && (BN_get_flags(p, BN_FLG_CONSTTIME) == 0)) {\n            BN_ULONG A = a->d[0];\n            ret = BN_mod_exp_mont_word(r, A, p, m, ctx, NULL);\n        } else\n# endif\n            ret = BN_mod_exp_mont(r, a, p, m, ctx, NULL);\n    } else\n#endif\n#ifdef RECP_MUL_MOD\n    {\n        ret = BN_mod_exp_recp(r, a, p, m, ctx);\n    }\n#else\n    {\n        ret = BN_mod_exp_simple(r, a, p, m, ctx);\n    }\n#endif\n    bn_check_top(r);\n    return (ret);\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 (val[0] == NULL)\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_CTX_get(BN_CTX *ctx)\n{\n    BIGNUM *ret;\n    CTXDBG_ENTRY("BN_CTX_get", ctx);\n    if (ctx->err_stack || ctx->too_many)\n        return NULL;\n    if ((ret = BN_POOL_get(&ctx->pool, ctx->flags)) == NULL) {\n        ctx->too_many = 1;\n        BNerr(BN_F_BN_CTX_GET, BN_R_TOO_MANY_TEMPORARY_VARIABLES);\n        return NULL;\n    }\n    BN_zero(ret);\n    ctx->used++;\n    CTXDBG_RET(ctx, ret);\n    return ret;\n}', 'void BN_CTX_end(BN_CTX *ctx)\n{\n    CTXDBG_ENTRY("BN_CTX_end", ctx);\n    if (ctx->err_stack)\n        ctx->err_stack--;\n    else {\n        unsigned int fp = BN_STACK_pop(&ctx->stack);\n        if (fp < ctx->used)\n            BN_POOL_release(&ctx->pool, ctx->used - fp);\n        ctx->used = fp;\n        ctx->too_many = 0;\n    }\n    CTXDBG_EXIT(ctx);\n}', 'static void BN_POOL_release(BN_POOL *p, unsigned int num)\n{\n    unsigned int offset = (p->used - 1) % BN_CTX_POOL_SIZE;\n    p->used -= num;\n    while (num--) {\n        bn_check_top(p->current->vals + offset);\n        if (offset == 0) {\n            offset = BN_CTX_POOL_SIZE - 1;\n            p->current = p->current->prev;\n        } else\n            offset--;\n    }\n}']