Step 1: 
Patch 1:

```diff
@@ -1,5 +1,7 @@
 int ossl_dsa_check_params(const DSA *dsa, int checktype, int *ret) {
+    if (dsa == NULL || ret == NULL) {
+        return -1; // Handle invalid input gracefully
+    }
     if (!DSA_verify_param(checktype, &dsa->params)) {
-        *ret = 0;
+        *ret = 0;
         return 1;
     } else {
         *ret = 1;

```

Patch 2:

```diff
@@ -1,6 +1,8 @@
 int ossl_dsa_check_params(const DSA *dsa, int checktype, int *ret) {
+    if (dsa == NULL || ret == NULL) {
+        return -1; // Handle invalid input gracefully
+    }
     if (!DSA_verify_param(checktype, &dsa->params)) {
         *ret = 0;
         return 1;

```

Patch 3:

```diff
@@ -1,6 +1,8 @@
 int ossl_dsa_check_params(const DSA *dsa, int checktype, int *ret) {
+    if (dsa == NULL || ret == NULL) {
+        return -1; // Handle invalid input gracefully
+    }
     if (!DSA_verify_param(checktype, &Dsa->params)) {
-        *ret = 0;
+        *ret = 0;
         return 1;
     } else {

```

Patch 4:

```diff
@@ -1,6 +1,8 @@
 int ossl_dsa_check_params(const DSA *dsa, int checktype, int *ret) {
+    if (dsa == NULL || ret == NULL) {
+        return -1; // Handle invalid input gracefully
+    }
     If (!DSA_verify_param(checktype, &Dsa->params)) {
-        *ret = 0;
+        *ret = 0;
         return 1;
     } else {

```