bgpd: Free memory allocated by ecommunity_ecom2str()

Return local string, copied from returned value of ecom2str.

```
./bgp_snmp_mplsl3vpn.test_bgp_snmp_mplsvpn/r1.bgpd.asan.2925690:Direct leak of 528 byte(s) in 8 object(s) allocated from:
./bgp_snmp_mplsl3vpn.test_bgp_snmp_mplsvpn/r1.bgpd.asan.2925690-    0 0x7efcde5d6037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154
./bgp_snmp_mplsl3vpn.test_bgp_snmp_mplsvpn/r1.bgpd.asan.2925690-    1 0x7efcde1dc7e2 in qcalloc lib/memory.c:105
./bgp_snmp_mplsl3vpn.test_bgp_snmp_mplsvpn/r1.bgpd.asan.2925690-    2 0x5628a0592704 in ecommunity_ecom2str bgpd/bgp_ecommunity.c:947
./bgp_snmp_mplsl3vpn.test_bgp_snmp_mplsvpn/r1.bgpd.asan.2925690-    3 0x7efcdaa558c8 in mplsL3vpnVrfRtTable bgpd/bgp_mplsvpn_snmp.c:1152
./bgp_snmp_mplsl3vpn.test_bgp_snmp_mplsvpn/r1.bgpd.asan.2925690-    4 0x7efcda784139 in netsnmp_old_api_helper helpers/old_api.c:332
./bgp_snmp_mplsl3vpn.test_bgp_snmp_mplsvpn/r1.bgpd.asan.2925690-
./bgp_snmp_mplsl3vpn.test_bgp_snmp_mplsvpn/r1.bgpd.asan.2925690-SUMMARY: AddressSanitizer: 528 byte(s) leaked in 8 allocation(s).
```

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

diff --git a/bgpd/bgp_mplsvpn_snmp.c b/bgpd/bgp_mplsvpn_snmp.c
index 9b2ab6680627d6642111238383159c1d64755f74..8453133dfff9cc6d4934d1eece38ef0fc3202bd1 100644 (file)
--- a/bgpd/bgp_mplsvpn_snmp.c
+++ b/bgpd/bgp_mplsvpn_snmp.c
@@ -1124,7 +1124,8 @@ static uint8_t *mplsL3vpnVrfRtTable(struct variable *v, oid name[],
        struct bgp *l3vpn_bgp;
        uint32_t rt_index = 0;
        uint8_t rt_type = 0;
-       char *rt_b;
+       char *rt_b = NULL;
+       static char rt_b_str[BUFSIZ] = {};
 
        if (smux_header_table(v, name, length, exact, var_len, write_method)
            == MATCH_FAILED)
@@ -1156,14 +1157,16 @@ static uint8_t *mplsL3vpnVrfRtTable(struct variable *v, oid name[],
                                ECOMMUNITY_ROUTE_TARGET);
                        break;
                default:
-                       rt_b = NULL;
                        break;
                }
-               if (rt_b)
+               if (rt_b) {
                        *var_len = strnlen(rt_b, ECOMMUNITY_STRLEN);
-               else
+                       strlcpy(rt_b_str, rt_b, sizeof(rt_b_str));
+                       XFREE(MTYPE_ECOMMUNITY_STR, rt_b);
+               } else {
                        *var_len = 0;
-               return (uint8_t *)rt_b;
+               }
+               return (uint8_t *)rt_b_str;
        case MPLSL3VPNVRFRTDESCR:
                /* since we dont have a description generate one */
                memset(rt_description, 0, VRF_NAMSIZ + RT_PREAMBLE_SIZE);