getaddrinfo(3) leak in whois(1)

[Jeremie Courreges-Anglas]

Hi,

here are two tweaks for whois.c:
- in whois() call freeaddrinfo(3) asap, there is no reason to keep the
  results around for longer than necessary.  whois() is recursive so
  this should reduce the amount of memory used when following redirects.
- choose_server() doesn't attempt to free the getaddrinfo(3) results,
  I think the least intrusive way is to rely on the fact that
  getaddrinfo(3) only updates the "res" pointer on a successful call.
  Tested with ./obj/whois nic.africa

Comments, ok?


Index: whois.c
===================================================================
RCS file: /d/cvs/src/usr.bin/whois/whois.c,v
retrieving revision 1.57
diff -u -p -p -u -r1.57 whois.c
--- whois.c     17 Jun 2018 15:34:54 -0000      1.57
+++ whois.c     18 Jun 2018 18:05:17 -0000
@@ -196,13 +196,13 @@ whois(const char *query, const char *ser
                }
                break;  /*okay*/
        }
+       freeaddrinfo(res);
        if (s == -1) {
                if (reason) {
                        errno = error;
                        warn("%s: %s", server, reason);
                } else
                        warn("unknown error in connection attempt");
-               freeaddrinfo(res);
                return (1);
        }
 
@@ -269,7 +269,7 @@ whois(const char *query, const char *ser
                error = whois(query, nhost, port, 0);
                free(nhost);
        }
-       freeaddrinfo(res);
+
        return (error);
 }
 
@@ -287,7 +287,7 @@ choose_server(const char *name, const ch
        char *server;
        const char *qhead;
        char *ep;
-       struct addrinfo hints, *res;
+       struct addrinfo hints, *res = NULL;
 
        memset(&hints, 0, sizeof(hints));
        hints.ai_flags = 0;
@@ -339,6 +339,8 @@ choose_server(const char *name, const ch
                if (asprintf(&server, "%s%s", qhead, QNICHOST_TAIL) == -1)
                        err(1, NULL);
        }
+       if (res != NULL)
+               freeaddrinfo(res);
 
        *tofree = server;
        return (server);


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