crypto/ec/ecdsa_ossl.c:415: error: BUFFER_OVERRUN_L3
  Offset: [-1, +oo] Size: [1, +oo] by call to `BN_mod_inverse`.
Showing all 23 steps of the trace


crypto/ec/ecdsa_ossl.c:389:5: Call
387.           return -1;
388.       }
389.       BN_CTX_start(ctx);
           ^
390.       u1 = BN_CTX_get(ctx);
391.       u2 = 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/ec/ecdsa_ossl.c:415:14: Call
413.       /* Check if optimized inverse is implemented */
414.       if (EC_GROUP_do_inverse_ord(group, u2, sig->s, ctx) == 0) {
415.           if (!BN_mod_inverse(u2, sig->s, order, ctx)) {
                    ^
416.               ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);
417.               goto err;

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:190:5: Call
          188.       }
          189.   
          190.       BN_CTX_start(ctx);
                     ^
          191.       res = (dv == NULL) ? BN_CTX_get(ctx) : dv;
          192.       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:410:5: Call
          408.       if (no_branch)
          409.           bn_correct_top(res);
          410.       BN_CTX_end(ctx);
                     ^
          411.       return 1;
          412.    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_mod_inverse` 
              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 ossl_ecdsa_verify_sig(const unsigned char *dgst, int dgst_len,\n                          const ECDSA_SIG *sig, EC_KEY *eckey)\n{\n    int ret = -1, i;\n    BN_CTX *ctx;\n    const BIGNUM *order;\n    BIGNUM *u1, *u2, *m, *X;\n    EC_POINT *point = NULL;\n    const EC_GROUP *group;\n    const EC_POINT *pub_key;\n    if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL ||\n        (pub_key = EC_KEY_get0_public_key(eckey)) == NULL || sig == NULL) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, EC_R_MISSING_PARAMETERS);\n        return -1;\n    }\n    if (!EC_KEY_can_sign(eckey)) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);\n        return -1;\n    }\n    ctx = BN_CTX_new();\n    if (ctx == NULL) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_MALLOC_FAILURE);\n        return -1;\n    }\n    BN_CTX_start(ctx);\n    u1 = BN_CTX_get(ctx);\n    u2 = BN_CTX_get(ctx);\n    m = BN_CTX_get(ctx);\n    X = BN_CTX_get(ctx);\n    if (X == NULL) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);\n        goto err;\n    }\n    order = EC_GROUP_get0_order(group);\n    if (order == NULL) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);\n        goto err;\n    }\n    if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||\n        BN_ucmp(sig->r, order) >= 0 || BN_is_zero(sig->s) ||\n        BN_is_negative(sig->s) || BN_ucmp(sig->s, order) >= 0) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, EC_R_BAD_SIGNATURE);\n        ret = 0;\n        goto err;\n    }\n    if (EC_GROUP_do_inverse_ord(group, u2, sig->s, ctx) == 0) {\n        if (!BN_mod_inverse(u2, sig->s, order, ctx)) {\n            ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);\n            goto err;\n        }\n    }\n    i = BN_num_bits(order);\n    if (8 * dgst_len > i)\n        dgst_len = (i + 7) / 8;\n    if (!BN_bin2bn(dgst, dgst_len, m)) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);\n        goto err;\n    }\n    if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);\n        goto err;\n    }\n    if (!BN_mod_mul(u1, m, u2, order, ctx)) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);\n        goto err;\n    }\n    if (!BN_mod_mul(u2, sig->r, u2, order, ctx)) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);\n        goto err;\n    }\n    if ((point = EC_POINT_new(group)) == NULL) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_MALLOC_FAILURE);\n        goto err;\n    }\n    if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx)) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);\n        goto err;\n    }\n    if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==\n        NID_X9_62_prime_field) {\n        if (!EC_POINT_get_affine_coordinates_GFp(group, point, X, NULL, ctx)) {\n            ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);\n            goto err;\n        }\n    }\n#ifndef OPENSSL_NO_EC2M\n    else {\n        if (!EC_POINT_get_affine_coordinates_GF2m(group, point, X, NULL, ctx)) {\n            ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);\n            goto err;\n        }\n    }\n#endif\n    if (!BN_nnmod(u1, X, order, ctx)) {\n        ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);\n        goto err;\n    }\n    ret = (BN_ucmp(u1, sig->r) == 0);\n err:\n    BN_CTX_end(ctx);\n    BN_CTX_free(ctx);\n    EC_POINT_free(point);\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}', '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}']