CID 1508984: Dereference null return value

[maskit]

 72EVP_PKEY *
 73async_load_privkey(ENGINE *e, const char *s_key_id, UI_METHOD *ui_method, void *callback_data)
 74{
 75  fprintf(stderr, "Loading key %s\n", s_key_id);
   	1. returned_null: fopen returns NULL (checked 24 out of 30 times).
   	2. var_assigned: Assigning: f = NULL return value from fopen.
 76  FILE *f       = fopen(s_key_id, "r");
 77  EVP_PKEY *key = PEM_read_PrivateKey(f, NULL, NULL, NULL);
   	
CID 1508984 (#1 of 1): Dereference null return value (NULL_RETURNS)
3. dereference: Dereferencing a pointer that might be NULL f when calling fclose.
 78  fclose(f);
 79  return key;
 80}