Fix a failure to NULL a pointer freed on error.

Reported by the LibreSSL project as a follow on to CVE-2015-0209

Reviewed-by: Richard Levitte <levitte@openssl.org>

crypto/asn1/x_x509.c

@@ -168,8 +168,14 @@ X509 *d2i_X509_AUX(X509 **a, const unsigned char **pp, long length)
 {
     const unsigned char *q;
     X509 *ret;
+    int freeret = 0;
+
     /* Save start position */
     q = *pp;
+
+    if(!a || *a == NULL) {
+        freeret = 1;
+    }
     ret = d2i_X509(a, pp, length);
     /* If certificate unreadable then forget it */
     if (!ret)
@@ -182,7 +188,11 @@ X509 *d2i_X509_AUX(X509 **a, const unsigned char **pp, long length)
         goto err;
     return ret;
  err:
-    X509_free(ret);
+    if(freeret) {
+        X509_free(ret);
+        if (a)
+            *a = NULL;
+    }
     return NULL;
 }
 

crypto/ec/ec_asn1.c

@@ -1226,16 +1226,19 @@ EC_KEY *d2i_ECParameters(EC_KEY **a, const unsigned char **in, long len)
             ECerr(EC_F_D2I_ECPARAMETERS, ERR_R_MALLOC_FAILURE);
             return NULL;
         }
-        if (a)
-            *a = ret;
     } else
         ret = *a;
 
     if (!d2i_ECPKParameters(&ret->group, in, len)) {
         ECerr(EC_F_D2I_ECPARAMETERS, ERR_R_EC_LIB);
+        if (a == NULL || *a != ret)
+             EC_KEY_free(ret);
         return NULL;
     }
 
+    if (a)
+        *a = ret;
+
     return ret;
 }