Language: C
Label: vulnerable
CWE: CWE-190 \u2014 Integer Overflow or Wraparound
The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control.

Code:
static void ed_mul_sim_plain(ed_t r, const ed_t p, const bn_t k, const ed_t q,
		const bn_t m, const ed_t *t) {
	int i, l, l0, l1, n0, n1, w, gen;
	int8_t naf0[RLC_FP_BITS + 1], naf1[RLC_FP_BITS + 1], *_k, *_m;
	ed_t t0[1 << (ED_WIDTH - 2)];
	ed_t t1[1 << (ED_WIDTH - 2)];

	RLC_TRY {
		gen = (t == NULL ? 0 : 1);
		if (!gen) {
			for (i = 0; i < (1 << (ED_WIDTH - 2)); i++) {
				ed_null(t0[i]);
				ed_new(t0[i]);
			}
			ed_tab(t0, p, ED_WIDTH);
			t = (const ed_t *)t0;
		}

		/* Prepare the precomputation table. */
		for (i = 0; i < (1 << (ED_WIDTH - 2)); i++) {
			ed_null(t1[i]);
			ed_new(t1[i]);
		}
		/* Compute the precomputation table. */
		ed_tab(t1, q, ED_WIDTH);

		/* Compute the w-TNAF representation of k. */
		if (gen) {
			w = ED_DEPTH;
		} else {
			w = ED_WIDTH;
		}
		l0 = l1 = RLC_FP_BITS + 1;
		bn_rec_naf(naf0, &l0, k, w);
		bn_rec_naf(naf1, &l1, m, ED_WIDTH);

		l = RLC_MAX(l0, l1);
		if (bn_sign(k) == RLC_NEG) {
			for (i =  0; i < l0; i++) {
				naf0[i] = -naf0[i];
			}
		}
		if (bn_sign(m) == RLC_NEG) {
			for (i =  0; i < l1; i++) {
				naf1[i] = -naf1[i];
			}
		}

		_k = naf0 + l - 1;
		_m = naf1 + l - 1;
		ed_set_infty(r);
		for (i = l - 1; i >= 0; i--, _k--, _m--) {
			ed_dbl(r, r);

			n0 = *_k;
			n1 = *_m;
			if (n0 > 0) {
				ed_add(r, r, t[n0 / 2]);
			}
			if (n0 < 0) {
				ed_sub(r, r, t[-n0 / 2]);
			}
			if (n1 > 0) {
				ed_add(r, r, t1[n1 / 2]);
			}
			if (n1 < 0) {
				ed_sub(r, r, t1[-n1 / 2]);
			}
		}
		/* Convert r to affine coordinates. */
		ed_norm(r, r);
	}
	RLC_CATCH_ANY {
		RLC_THROW(ERR_CAUGHT);
	}
	RLC_FINALLY {
		/* Free the precomputation tables. */
		if (!gen) {
			for (i = 0; i < 1 << (ED_WIDTH - 2); i++) {
				ed_free(t0[i]);
			}
		}
		for (i = 0; i < 1 << (ED_WIDTH - 2); i++) {
			ed_free(t1[i]);
		}
	}
}