tools/testing/nvdimm: stricter bounds checking for error injection commands

Ensure that the in/out sizes passed in the nd_cmd_package are sane for
the fixed output size commands (i.e. inject error and clear injected
error).
Reported-by: Dariusz Dokupil <dariusz.dokupil@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

tools/testing/nvdimm/test/nfit.c

@@ -488,7 +488,7 @@ static int nfit_test_cmd_ars_error_inject(struct nfit_test *t,
 {
 	int rc;
 
-	if (buf_len < sizeof(*err_inj)) {
+	if (buf_len != sizeof(*err_inj)) {
 		rc = -EINVAL;
 		goto err;
 	}
@@ -519,7 +519,7 @@ static int nfit_test_cmd_ars_inject_clear(struct nfit_test *t,
 {
 	int rc;
 
-	if (buf_len < sizeof(*err_clr)) {
+	if (buf_len != sizeof(*err_clr)) {
 		rc = -EINVAL;
 		goto err;
 	}