static int isofs_dentry_cmp_common(
		unsigned int len, const char *str,
		const struct qstr *name, int ms, int ci)
{
	int alen, blen;

	/* A filename cannot end in '.' or we treat it like it has none */
	alen = name->len;
	blen = len;
	if (ms) {
		while (alen && name->name[alen-1] == '.')
			alen--;
		while (blen && str[blen-1] == '.')
			blen--;
	}
	if (alen == blen) {
		if (ci) {
			if (strnicmp(name->name, str, alen) == 0)
				return 0;
		} else {
			if (strncmp(name->name, str, alen) == 0)
				return 0;
		}
	}
	return 1;
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.