[PATCH] nat: fix use after free in forward_sccp_to_bts

[pablo]

From: Pablo Neira Ayuso <pa...@gnumonks.org>

valgrind detected an use after free in the path of forward_sccp_to_bts.
The 'parsed' object is referenced from update_con_authorize.
---
 openbsc/src/osmo-bsc_nat/bsc_nat.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat.c 
b/openbsc/src/osmo-bsc_nat/bsc_nat.c
index b9bf36c..be8d56a 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat.c
@@ -718,15 +718,18 @@ static int forward_sccp_to_bts(struct bsc_msc_connection 
*msc_con, struct msgb *
                        LOGP(DNAT, LOGL_ERROR, "Unknown connection for msg 
type: 0x%x from the MSC.\n", parsed->sccp_type);
        }
 
-       talloc_free(parsed);
-       if (!con)
+       if (!con) {
+               talloc_free(parsed);
                return -1;
+       }
        if (!con->bsc->authenticated) {
+               talloc_free(parsed);
                LOGP(DNAT, LOGL_ERROR, "Selected BSC not authenticated.\n");
                return -1;
        }
 
        update_con_authorize(con, parsed, msg);
+       talloc_free(parsed);
 
        bsc_send_data(con->bsc, msg->l2h, msgb_l2len(msg), proto);
        return 0;
-- 
1.7.10.4