crypto/bn/bn_mont.c:75: error: BUFFER_OVERRUN_S2
  Offset: [max(1, `mont->N.top`), +oo] (⇐ [0, +oo] + [max(1, `mont->N.top`), `mont->N.top`]) Size: [0, 8388607] by call to `bn_from_montgomery_word`.
Showing all 10 steps of the trace


crypto/bn/bn_mont.c:37:1: Parameter `mont->N.top`
35.   }
36.   
37. > int bn_mul_mont_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
38.                             BN_MONT_CTX *mont, BN_CTX *ctx)
39.   {

crypto/bn/bn_mont.c:75:10: Call
73.       /* reduce from aRR to aR */
74.   #ifdef MONT_WORD
75.       if (!bn_from_montgomery_word(r, tmp, mont))
               ^
76.           goto err;
77.   #else

crypto/bn/bn_mont.c:125:21: <Offset trace>
123.        * includes |carry| which is stored separately.
124.        */
125.       for (carry = 0, i = 0; i < nl; i++, rp++) {
                           ^
126.           v = bn_mul_add_words(rp, np, nl, (rp[0] * n0) & BN_MASK2);
127.           v = (v + carry + rp[nl]) & BN_MASK2;

crypto/bn/bn_mont.c:125:21: Assignment
  123.        * includes |carry| which is stored separately.
  124.        */
  125.       for (carry = 0, i = 0; i < nl; i++, rp++) {
                             ^
  126.           v = bn_mul_add_words(rp, np, nl, (rp[0] * n0) & BN_MASK2);
  127.           v = (v + carry + rp[nl]) & BN_MASK2;

crypto/bn/bn_mont.c:88:1: <Length trace>
86.   
87.   #ifdef MONT_WORD
88. > static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
89.   {
90.       BIGNUM *n;

crypto/bn/bn_mont.c:88:1: Parameter `*r->d`
  86.   
  87.   #ifdef MONT_WORD
  88. > static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
  89.   {
  90.       BIGNUM *n;

crypto/bn/bn_mont.c:103:9: Call
  101.   
  102.       max = (2 * nl);             /* carry is stored separately */
  103.       if (bn_wexpand(r, max) == NULL)
                 ^
  104.           return 0;
  105.   

crypto/bn/bn_lib.c:960:1: Parameter `*a->d`
    958.   }
    959.   
    960. > BIGNUM *bn_wexpand(BIGNUM *a, int words)
    961.   {
    962.       return (words <= a->dmax) ? a : bn_expand2(a, words);

crypto/bn/bn_mont.c:108:5: Assignment
  106.       r->neg ^= n->neg;
  107.       np = n->d;
  108.       rp = r->d;
             ^
  109.   
  110.       /* clear the top words of T */

crypto/bn/bn_mont.c:129:24: Array access: Offset: [max(1, mont->N.top), +oo] (⇐ [0, +oo] + [max(1, mont->N.top), mont->N.top]) Size: [0, 8388607] by call to `bn_from_montgomery_word` 
  127.           v = (v + carry + rp[nl]) & BN_MASK2;
  128.           carry |= (v != rp[nl]);
  129.           carry &= (v <= rp[nl]);
                                ^
  130.           rp[nl] = v;
  131.       }

static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
{
    BIGNUM *n;
    BN_ULONG *ap, *np, *rp, n0, v, carry;
    int nl, max, i;
    unsigned int rtop;
    n = &(mont->N);
    nl = n->top;
    if (nl == 0) {
        ret->top = 0;
        return 1;
    }
    max = (2 * nl);
    if (bn_wexpand(r, max) == NULL)
        return 0;
    r->neg ^= n->neg;
    np = n->d;
    rp = r->d;
    for (rtop = r->top, i = 0; i < max; i++) {
        v = (BN_ULONG)0 - ((i - rtop) >> (8 * sizeof(rtop) - 1));
        rp[i] &= v;
    }
    r->top = max;
    r->flags |= BN_FLG_FIXED_TOP;
    n0 = mont->n0[0];
    for (carry = 0, i = 0; i < nl; i++, rp++) {
        v = bn_mul_add_words(rp, np, nl, (rp[0] * n0) & BN_MASK2);
        v = (v + carry + rp[nl]) & BN_MASK2;
        carry |= (v != rp[nl]);
        carry &= (v <= rp[nl]);
        rp[nl] = v;
    }
    if (bn_wexpand(ret, nl) == NULL)
        return 0;
    ret->top = nl;
    ret->flags |= BN_FLG_FIXED_TOP;
    ret->neg = r->neg;
    rp = ret->d;
    ap = &(r->d[nl]);
    carry -= bn_sub_words(rp, ap, np, nl);
    for (i = 0; i < nl; i++) {
        rp[i] = (carry & ap[i]) | (~carry & rp[i]);
        ap[i] = 0;
    }
    return 1;
}
['int bn_mul_mont_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,\n                          BN_MONT_CTX *mont, BN_CTX *ctx)\n{\n    BIGNUM *tmp;\n    int ret = 0;\n    int num = mont->N.top;\n#if defined(OPENSSL_BN_ASM_MONT) && defined(MONT_WORD)\n    if (num > 1 && a->top == num && b->top == num) {\n        if (bn_wexpand(r, num) == NULL)\n            return 0;\n        if (bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) {\n            r->neg = a->neg ^ b->neg;\n            r->top = num;\n            r->flags |= BN_FLG_FIXED_TOP;\n            return 1;\n        }\n    }\n#endif\n    if ((a->top + b->top) > 2 * num)\n        return 0;\n    BN_CTX_start(ctx);\n    tmp = BN_CTX_get(ctx);\n    if (tmp == NULL)\n        goto err;\n    bn_check_top(tmp);\n    if (a == b) {\n        if (!bn_sqr_fixed_top(tmp, a, ctx))\n            goto err;\n    } else {\n        if (!bn_mul_fixed_top(tmp, a, b, ctx))\n            goto err;\n    }\n#ifdef MONT_WORD\n    if (!bn_from_montgomery_word(r, tmp, mont))\n        goto err;\n#else\n    if (!BN_from_montgomery(r, tmp, mont, ctx))\n        goto err;\n#endif\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    return ret;\n}', 'static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)\n{\n    BIGNUM *n;\n    BN_ULONG *ap, *np, *rp, n0, v, carry;\n    int nl, max, i;\n    unsigned int rtop;\n    n = &(mont->N);\n    nl = n->top;\n    if (nl == 0) {\n        ret->top = 0;\n        return 1;\n    }\n    max = (2 * nl);\n    if (bn_wexpand(r, max) == NULL)\n        return 0;\n    r->neg ^= n->neg;\n    np = n->d;\n    rp = r->d;\n    for (rtop = r->top, i = 0; i < max; i++) {\n        v = (BN_ULONG)0 - ((i - rtop) >> (8 * sizeof(rtop) - 1));\n        rp[i] &= v;\n    }\n    r->top = max;\n    r->flags |= BN_FLG_FIXED_TOP;\n    n0 = mont->n0[0];\n    for (carry = 0, i = 0; i < nl; i++, rp++) {\n        v = bn_mul_add_words(rp, np, nl, (rp[0] * n0) & BN_MASK2);\n        v = (v + carry + rp[nl]) & BN_MASK2;\n        carry |= (v != rp[nl]);\n        carry &= (v <= rp[nl]);\n        rp[nl] = v;\n    }\n    if (bn_wexpand(ret, nl) == NULL)\n        return 0;\n    ret->top = nl;\n    ret->flags |= BN_FLG_FIXED_TOP;\n    ret->neg = r->neg;\n    rp = ret->d;\n    ap = &(r->d[nl]);\n    carry -= bn_sub_words(rp, ap, np, nl);\n    for (i = 0; i < nl; i++) {\n        rp[i] = (carry & ap[i]) | (~carry & rp[i]);\n        ap[i] = 0;\n    }\n    return 1;\n}', 'BIGNUM *bn_wexpand(BIGNUM *a, int words)\n{\n    return (words <= a->dmax) ? a : bn_expand2(a, words);\n}']