crypto/bn/bn_prime.c:215: error: BUFFER_OVERRUN_L3
  Offset: [-1, +oo] Size: [1, +oo] by call to `BN_MONT_CTX_set`.
Showing all 28 steps of the trace


crypto/bn/bn_prime.c:151:1: Parameter `ctx_passed->stack.depth`
149.   }
150.   
151. > int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
152.                               int do_trial_division, BN_GENCB *cb)
153.   {

crypto/bn/bn_prime.c:186:5: Call
184.       else if ((ctx = BN_CTX_new()) == NULL)
185.           goto err;
186.       BN_CTX_start(ctx);
           ^
187.   
188.       A1 = BN_CTX_get(ctx);

crypto/bn/bn_ctx.c:181:1: Parameter `ctx->stack.depth`
  179.   }
  180.   
  181. > void BN_CTX_start(BN_CTX *ctx)
  182.   {
  183.       CTXDBG_ENTRY("BN_CTX_start", ctx);

crypto/bn/bn_prime.c:215:10: Call
213.       if (mont == NULL)
214.           goto err;
215.       if (!BN_MONT_CTX_set(mont, a, ctx))
                ^
216.           goto err;
217.   

crypto/bn/bn_mont.c:247:1: Parameter `ctx->stack.depth`
  245.   }
  246.   
  247. > int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
  248.   {
  249.       int ret = 0;

crypto/bn/bn_mont.c:255:5: Call
  253.           return 0;
  254.   
  255.       BN_CTX_start(ctx);
             ^
  256.       if ((Ri = BN_CTX_get(ctx)) == NULL)
  257.           goto err;

crypto/bn/bn_ctx.c:181:1: Parameter `ctx->stack.depth`
    179.   }
    180.   
    181. > void BN_CTX_start(BN_CTX *ctx)
    182.   {
    183.       CTXDBG_ENTRY("BN_CTX_start", ctx);

crypto/bn/bn_mont.c:329:14: Call
  327.           tmod.top = buf[0] != 0 ? 1 : 0;
  328.           /* Ri = R^-1 mod N */
  329.           if ((BN_mod_inverse(Ri, R, &tmod, ctx)) == NULL)
                      ^
  330.               goto err;
  331.           if (!BN_lshift(Ri, Ri, BN_BITS2))

crypto/bn/bn_gcd.c:124:1: Parameter `ctx->stack.depth`
    122.                                           BN_CTX *ctx);
    123.   
    124. > BIGNUM *BN_mod_inverse(BIGNUM *in,
    125.                          const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)
    126.   {

crypto/bn/bn_gcd.c:129:10: Call
    127.       BIGNUM *rv;
    128.       int noinv;
    129.       rv = int_bn_mod_inverse(in, a, n, ctx, &noinv);
                    ^
    130.       if (noinv)
    131.           BNerr(BN_F_BN_MOD_INVERSE, BN_R_NO_INVERSE);

crypto/bn/bn_gcd.c:135:1: Parameter `ctx->stack.depth`
      133.   }
      134.   
      135. > BIGNUM *int_bn_mod_inverse(BIGNUM *in,
      136.                              const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx,
      137.                              int *pnoinv)

crypto/bn/bn_gcd.c:148:16: Call
      146.       if ((BN_get_flags(a, BN_FLG_CONSTTIME) != 0)
      147.           || (BN_get_flags(n, BN_FLG_CONSTTIME) != 0)) {
      148.           return BN_mod_inverse_no_branch(in, a, n, ctx);
                            ^
      149.       }
      150.   

crypto/bn/bn_gcd.c:451:1: Parameter `ctx->stack.depth`
        449.    * not contain branches that may leak sensitive information.
        450.    */
        451. > static BIGNUM *BN_mod_inverse_no_branch(BIGNUM *in,
        452.                                           const BIGNUM *a, const BIGNUM *n,
        453.                                           BN_CTX *ctx)

crypto/bn/bn_gcd.c:462:5: Call
        460.       bn_check_top(n);
        461.   
        462.       BN_CTX_start(ctx);
                   ^
        463.       A = BN_CTX_get(ctx);
        464.       B = BN_CTX_get(ctx);

crypto/bn/bn_ctx.c:181:1: Parameter `ctx->stack.depth`
          179.   }
          180.   
          181. > void BN_CTX_start(BN_CTX *ctx)
          182.   {
          183.       CTXDBG_ENTRY("BN_CTX_start", ctx);

crypto/bn/bn_gcd.c:497:18: Call
        495.               bn_init(&local_B);
        496.               BN_with_flags(&local_B, B, BN_FLG_CONSTTIME);
        497.               if (!BN_nnmod(B, &local_B, A, ctx))
                                ^
        498.                   goto err;
        499.               /* Ensure local_B goes out of scope before any further use of B */

crypto/bn/bn_mod.c:13:1: Parameter `ctx->stack.depth`
          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:193:5: Call
            191.       }
            192.   
            193.       BN_CTX_start(ctx);
                       ^
            194.       res = (dv == NULL) ? BN_CTX_get(ctx) : dv;
            195.       tmp = BN_CTX_get(ctx);

crypto/bn/bn_ctx.c:181:1: Parameter `*ctx->stack.indexes`
              179.   }
              180.   
              181. > void BN_CTX_start(BN_CTX *ctx)
              182.   {
              183.       CTXDBG_ENTRY("BN_CTX_start", ctx);

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->stack.indexes`
              193.   }
              194.   
              195. > void BN_CTX_end(BN_CTX *ctx)
              196.   {
              197.       CTXDBG_ENTRY("BN_CTX_end", ctx);

crypto/bn/bn_ctx.c:201:27: Call
              199.           ctx->err_stack--;
              200.       else {
              201.           unsigned int fp = BN_STACK_pop(&ctx->stack);
                                               ^
              202.           /* Does this stack frame have anything to release? */
              203.           if (fp < ctx->used)

crypto/bn/bn_ctx.c:271:1: <Offset trace>
269.   }
270.   
271. > static unsigned int BN_STACK_pop(BN_STACK *st)
272.   {
273.       return st->indexes[--(st->depth)];

crypto/bn/bn_ctx.c:271:1: Parameter `st->depth`
                269.   }
                270.   
                271. > static unsigned int BN_STACK_pop(BN_STACK *st)
                272.   {
                273.       return st->indexes[--(st->depth)];

crypto/bn/bn_ctx.c:271:1: <Length trace>
269.   }
270.   
271. > static unsigned int BN_STACK_pop(BN_STACK *st)
272.   {
273.       return st->indexes[--(st->depth)];

crypto/bn/bn_ctx.c:271:1: Parameter `*st->indexes`
                269.   }
                270.   
                271. > static unsigned int BN_STACK_pop(BN_STACK *st)
                272.   {
                273.       return st->indexes[--(st->depth)];

crypto/bn/bn_ctx.c:273:12: Array access: Offset: [-1, +oo] Size: [1, +oo] by call to `BN_MONT_CTX_set` 
                271.   static unsigned int BN_STACK_pop(BN_STACK *st)
                272.   {
                273.       return st->indexes[--(st->depth)];
                                  ^
                274.   }
                275.   

static unsigned int BN_STACK_pop(BN_STACK *st)
{
    return st->indexes[--(st->depth)];
}
['int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,\n                            int do_trial_division, BN_GENCB *cb)\n{\n    int i, j, ret = -1;\n    int k;\n    BN_CTX *ctx = NULL;\n    BIGNUM *A1, *A1_odd, *check;\n    BN_MONT_CTX *mont = NULL;\n    if (BN_cmp(a, BN_value_one()) <= 0)\n        return 0;\n    if (checks == BN_prime_checks)\n        checks = BN_prime_checks_for_size(BN_num_bits(a));\n    if (!BN_is_odd(a))\n        return BN_is_word(a, 2);\n    if (do_trial_division) {\n        for (i = 1; i < NUMPRIMES; i++) {\n            BN_ULONG mod = BN_mod_word(a, primes[i]);\n            if (mod == (BN_ULONG)-1)\n                goto err;\n            if (mod == 0)\n                return BN_is_word(a, primes[i]);\n        }\n        if (!BN_GENCB_call(cb, 1, -1))\n            goto err;\n    }\n    if (ctx_passed != NULL)\n        ctx = ctx_passed;\n    else if ((ctx = BN_CTX_new()) == NULL)\n        goto err;\n    BN_CTX_start(ctx);\n    A1 = BN_CTX_get(ctx);\n    A1_odd = BN_CTX_get(ctx);\n    check = BN_CTX_get(ctx);\n    if (check == NULL)\n        goto err;\n    if (!BN_copy(A1, a))\n        goto err;\n    if (!BN_sub_word(A1, 1))\n        goto err;\n    if (BN_is_zero(A1)) {\n        ret = 0;\n        goto err;\n    }\n    k = 1;\n    while (!BN_is_bit_set(A1, k))\n        k++;\n    if (!BN_rshift(A1_odd, A1, k))\n        goto err;\n    mont = BN_MONT_CTX_new();\n    if (mont == NULL)\n        goto err;\n    if (!BN_MONT_CTX_set(mont, a, ctx))\n        goto err;\n    for (i = 0; i < checks; i++) {\n        if (!BN_priv_rand_range(check, A1))\n            goto err;\n        if (!BN_add_word(check, 1))\n            goto err;\n        j = witness(check, a, A1, A1_odd, k, ctx, mont);\n        if (j == -1)\n            goto err;\n        if (j) {\n            ret = 0;\n            goto err;\n        }\n        if (!BN_GENCB_call(cb, 1, i))\n            goto err;\n    }\n    ret = 1;\n err:\n    if (ctx != NULL) {\n        BN_CTX_end(ctx);\n        if (ctx_passed == NULL)\n            BN_CTX_free(ctx);\n    }\n    BN_MONT_CTX_free(mont);\n    return (ret);\n}', 'void BN_CTX_start(BN_CTX *ctx)\n{\n    CTXDBG_ENTRY("BN_CTX_start", ctx);\n    if (ctx->err_stack || ctx->too_many)\n        ctx->err_stack++;\n    else if (!BN_STACK_push(&ctx->stack, ctx->used)) {\n        BNerr(BN_F_BN_CTX_START, BN_R_TOO_MANY_TEMPORARY_VARIABLES);\n        ctx->err_stack++;\n    }\n    CTXDBG_EXIT(ctx);\n}', 'int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)\n{\n    int ret = 0;\n    BIGNUM *Ri, *R;\n    if (BN_is_zero(mod))\n        return 0;\n    BN_CTX_start(ctx);\n    if ((Ri = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    R = &(mont->RR);\n    if (!BN_copy(&(mont->N), mod))\n        goto err;\n    mont->N.neg = 0;\n#ifdef MONT_WORD\n    {\n        BIGNUM tmod;\n        BN_ULONG buf[2];\n        bn_init(&tmod);\n        tmod.d = buf;\n        tmod.dmax = 2;\n        tmod.neg = 0;\n        if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)\n            BN_set_flags(&tmod, BN_FLG_CONSTTIME);\n        mont->ri = (BN_num_bits(mod) + (BN_BITS2 - 1)) / BN_BITS2 * BN_BITS2;\n# if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)\n        BN_zero(R);\n        if (!(BN_set_bit(R, 2 * BN_BITS2)))\n            goto err;\n        tmod.top = 0;\n        if ((buf[0] = mod->d[0]))\n            tmod.top = 1;\n        if ((buf[1] = mod->top > 1 ? mod->d[1] : 0))\n            tmod.top = 2;\n        if ((BN_mod_inverse(Ri, R, &tmod, ctx)) == NULL)\n            goto err;\n        if (!BN_lshift(Ri, Ri, 2 * BN_BITS2))\n            goto err;\n        if (!BN_is_zero(Ri)) {\n            if (!BN_sub_word(Ri, 1))\n                goto err;\n        } else {\n            if (bn_expand(Ri, (int)sizeof(BN_ULONG) * 2) == NULL)\n                goto err;\n            Ri->neg = 0;\n            Ri->d[0] = BN_MASK2;\n            Ri->d[1] = BN_MASK2;\n            Ri->top = 2;\n        }\n        if (!BN_div(Ri, NULL, Ri, &tmod, ctx))\n            goto err;\n        mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;\n        mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0;\n# else\n        BN_zero(R);\n        if (!(BN_set_bit(R, BN_BITS2)))\n            goto err;\n        buf[0] = mod->d[0];\n        buf[1] = 0;\n        tmod.top = buf[0] != 0 ? 1 : 0;\n        if ((BN_mod_inverse(Ri, R, &tmod, ctx)) == NULL)\n            goto err;\n        if (!BN_lshift(Ri, Ri, BN_BITS2))\n            goto err;\n        if (!BN_is_zero(Ri)) {\n            if (!BN_sub_word(Ri, 1))\n                goto err;\n        } else {\n            if (!BN_set_word(Ri, BN_MASK2))\n                goto err;\n        }\n        if (!BN_div(Ri, NULL, Ri, &tmod, ctx))\n            goto err;\n        mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;\n        mont->n0[1] = 0;\n# endif\n    }\n#else\n    {\n        mont->ri = BN_num_bits(&mont->N);\n        BN_zero(R);\n        if (!BN_set_bit(R, mont->ri))\n            goto err;\n        if ((BN_mod_inverse(Ri, R, &mont->N, ctx)) == NULL)\n            goto err;\n        if (!BN_lshift(Ri, Ri, mont->ri))\n            goto err;\n        if (!BN_sub_word(Ri, 1))\n            goto err;\n        if (!BN_div(&(mont->Ni), NULL, Ri, &mont->N, ctx))\n            goto err;\n    }\n#endif\n    BN_zero(&(mont->RR));\n    if (!BN_set_bit(&(mont->RR), mont->ri * 2))\n        goto err;\n    if (!BN_mod(&(mont->RR), &(mont->RR), &(mont->N), ctx))\n        goto err;\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    return ret;\n}', 'BIGNUM *BN_mod_inverse(BIGNUM *in,\n                       const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)\n{\n    BIGNUM *rv;\n    int noinv;\n    rv = int_bn_mod_inverse(in, a, n, ctx, &noinv);\n    if (noinv)\n        BNerr(BN_F_BN_MOD_INVERSE, BN_R_NO_INVERSE);\n    return rv;\n}', 'BIGNUM *int_bn_mod_inverse(BIGNUM *in,\n                           const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx,\n                           int *pnoinv)\n{\n    BIGNUM *A, *B, *X, *Y, *M, *D, *T, *R = NULL;\n    BIGNUM *ret = NULL;\n    int sign;\n    if (pnoinv)\n        *pnoinv = 0;\n    if ((BN_get_flags(a, BN_FLG_CONSTTIME) != 0)\n        || (BN_get_flags(n, BN_FLG_CONSTTIME) != 0)) {\n        return BN_mod_inverse_no_branch(in, a, n, ctx);\n    }\n    bn_check_top(a);\n    bn_check_top(n);\n    BN_CTX_start(ctx);\n    A = BN_CTX_get(ctx);\n    B = BN_CTX_get(ctx);\n    X = BN_CTX_get(ctx);\n    D = BN_CTX_get(ctx);\n    M = BN_CTX_get(ctx);\n    Y = BN_CTX_get(ctx);\n    T = BN_CTX_get(ctx);\n    if (T == NULL)\n        goto err;\n    if (in == NULL)\n        R = BN_new();\n    else\n        R = in;\n    if (R == NULL)\n        goto err;\n    BN_one(X);\n    BN_zero(Y);\n    if (BN_copy(B, a) == NULL)\n        goto err;\n    if (BN_copy(A, n) == NULL)\n        goto err;\n    A->neg = 0;\n    if (B->neg || (BN_ucmp(B, A) >= 0)) {\n        if (!BN_nnmod(B, B, A, ctx))\n            goto err;\n    }\n    sign = -1;\n    if (BN_is_odd(n) && (BN_num_bits(n) <= 2048)) {\n        int shift;\n        while (!BN_is_zero(B)) {\n            shift = 0;\n            while (!BN_is_bit_set(B, shift)) {\n                shift++;\n                if (BN_is_odd(X)) {\n                    if (!BN_uadd(X, X, n))\n                        goto err;\n                }\n                if (!BN_rshift1(X, X))\n                    goto err;\n            }\n            if (shift > 0) {\n                if (!BN_rshift(B, B, shift))\n                    goto err;\n            }\n            shift = 0;\n            while (!BN_is_bit_set(A, shift)) {\n                shift++;\n                if (BN_is_odd(Y)) {\n                    if (!BN_uadd(Y, Y, n))\n                        goto err;\n                }\n                if (!BN_rshift1(Y, Y))\n                    goto err;\n            }\n            if (shift > 0) {\n                if (!BN_rshift(A, A, shift))\n                    goto err;\n            }\n            if (BN_ucmp(B, A) >= 0) {\n                if (!BN_uadd(X, X, Y))\n                    goto err;\n                if (!BN_usub(B, B, A))\n                    goto err;\n            } else {\n                if (!BN_uadd(Y, Y, X))\n                    goto err;\n                if (!BN_usub(A, A, B))\n                    goto err;\n            }\n        }\n    } else {\n        while (!BN_is_zero(B)) {\n            BIGNUM *tmp;\n            if (BN_num_bits(A) == BN_num_bits(B)) {\n                if (!BN_one(D))\n                    goto err;\n                if (!BN_sub(M, A, B))\n                    goto err;\n            } else if (BN_num_bits(A) == BN_num_bits(B) + 1) {\n                if (!BN_lshift1(T, B))\n                    goto err;\n                if (BN_ucmp(A, T) < 0) {\n                    if (!BN_one(D))\n                        goto err;\n                    if (!BN_sub(M, A, B))\n                        goto err;\n                } else {\n                    if (!BN_sub(M, A, T))\n                        goto err;\n                    if (!BN_add(D, T, B))\n                        goto err;\n                    if (BN_ucmp(A, D) < 0) {\n                        if (!BN_set_word(D, 2))\n                            goto err;\n                    } else {\n                        if (!BN_set_word(D, 3))\n                            goto err;\n                        if (!BN_sub(M, M, B))\n                            goto err;\n                    }\n                }\n            } else {\n                if (!BN_div(D, M, A, B, ctx))\n                    goto err;\n            }\n            tmp = A;\n            A = B;\n            B = M;\n            if (BN_is_one(D)) {\n                if (!BN_add(tmp, X, Y))\n                    goto err;\n            } else {\n                if (BN_is_word(D, 2)) {\n                    if (!BN_lshift1(tmp, X))\n                        goto err;\n                } else if (BN_is_word(D, 4)) {\n                    if (!BN_lshift(tmp, X, 2))\n                        goto err;\n                } else if (D->top == 1) {\n                    if (!BN_copy(tmp, X))\n                        goto err;\n                    if (!BN_mul_word(tmp, D->d[0]))\n                        goto err;\n                } else {\n                    if (!BN_mul(tmp, D, X, ctx))\n                        goto err;\n                }\n                if (!BN_add(tmp, tmp, Y))\n                    goto err;\n            }\n            M = Y;\n            Y = X;\n            X = tmp;\n            sign = -sign;\n        }\n    }\n    if (sign < 0) {\n        if (!BN_sub(Y, n, Y))\n            goto err;\n    }\n    if (BN_is_one(A)) {\n        if (!Y->neg && BN_ucmp(Y, n) < 0) {\n            if (!BN_copy(R, Y))\n                goto err;\n        } else {\n            if (!BN_nnmod(R, Y, n, ctx))\n                goto err;\n        }\n    } else {\n        if (pnoinv)\n            *pnoinv = 1;\n        goto err;\n    }\n    ret = R;\n err:\n    if ((ret == NULL) && (in == NULL))\n        BN_free(R);\n    BN_CTX_end(ctx);\n    bn_check_top(ret);\n    return (ret);\n}', 'static BIGNUM *BN_mod_inverse_no_branch(BIGNUM *in,\n                                        const BIGNUM *a, const BIGNUM *n,\n                                        BN_CTX *ctx)\n{\n    BIGNUM *A, *B, *X, *Y, *M, *D, *T, *R = NULL;\n    BIGNUM *ret = NULL;\n    int sign;\n    bn_check_top(a);\n    bn_check_top(n);\n    BN_CTX_start(ctx);\n    A = BN_CTX_get(ctx);\n    B = BN_CTX_get(ctx);\n    X = BN_CTX_get(ctx);\n    D = BN_CTX_get(ctx);\n    M = BN_CTX_get(ctx);\n    Y = BN_CTX_get(ctx);\n    T = BN_CTX_get(ctx);\n    if (T == NULL)\n        goto err;\n    if (in == NULL)\n        R = BN_new();\n    else\n        R = in;\n    if (R == NULL)\n        goto err;\n    BN_one(X);\n    BN_zero(Y);\n    if (BN_copy(B, a) == NULL)\n        goto err;\n    if (BN_copy(A, n) == NULL)\n        goto err;\n    A->neg = 0;\n    if (B->neg || (BN_ucmp(B, A) >= 0)) {\n         {\n            BIGNUM local_B;\n            bn_init(&local_B);\n            BN_with_flags(&local_B, B, BN_FLG_CONSTTIME);\n            if (!BN_nnmod(B, &local_B, A, ctx))\n                goto err;\n        }\n    }\n    sign = -1;\n    while (!BN_is_zero(B)) {\n        BIGNUM *tmp;\n        {\n            BIGNUM local_A;\n            bn_init(&local_A);\n            BN_with_flags(&local_A, A, BN_FLG_CONSTTIME);\n            if (!BN_div(D, M, &local_A, B, ctx))\n                goto err;\n        }\n        tmp = A;\n        A = B;\n        B = M;\n        if (!BN_mul(tmp, D, X, ctx))\n            goto err;\n        if (!BN_add(tmp, tmp, Y))\n            goto err;\n        M = Y;\n        Y = X;\n        X = tmp;\n        sign = -sign;\n    }\n    if (sign < 0) {\n        if (!BN_sub(Y, n, Y))\n            goto err;\n    }\n    if (BN_is_one(A)) {\n        if (!Y->neg && BN_ucmp(Y, n) < 0) {\n            if (!BN_copy(R, Y))\n                goto err;\n        } else {\n            if (!BN_nnmod(R, Y, n, ctx))\n                goto err;\n        }\n    } else {\n        BNerr(BN_F_BN_MOD_INVERSE_NO_BRANCH, BN_R_NO_INVERSE);\n        goto err;\n    }\n    ret = R;\n err:\n    if ((ret == NULL) && (in == NULL))\n        BN_free(R);\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}', '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 unsigned int BN_STACK_pop(BN_STACK *st)\n{\n    return st->indexes[--(st->depth)];\n}']