Hello Patrick McHardy,
The patch 2bbb21168a90: "[NETFILTER]: nf_conntrack_sip: introduce URI
and header parameter parsing helpers" from Mar 25, 2008, leads to the
following static checker warning:
net/netfilter/nf_conntrack_sip.c:1230 process_register_request()
warn: bool is not less than zero.
net/netfilter/nf_conntrack_sip.c:1336 process_register_response()
warn: bool is not less than zero.
The problem is ct_sip_parse_numerical_param() returns zero on failure
but two of the callers expect negative error codes.
net/netfilter/nf_conntrack_sip.c
1307 if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES,
1308 &matchoff, &matchlen) > 0)
1309 expires = simple_strtoul(*dptr + matchoff, NULL, 10);
^^^^^^^
We set expires.
1310
1311 while (1) {
1312 unsigned int c_expires = expires;
^^^^^^^^^^^^^^^^^^^^
and c_expires.
1313
1314 ret = ct_sip_parse_header_uri(ct, *dptr, &coff, *datalen,
1315 SIP_HDR_CONTACT, &in_contact,
1316 &matchoff, &matchlen,
1317 &addr, &port);
1318 if (ret < 0) {
1319 nf_ct_helper_log(skb, ct, "cannot parse contact");
1320 return NF_DROP;
1321 } else if (ret == 0)
1322 break;
1323
1324 /* We don't support third-party registrations */
1325 if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3, &addr))
1326 continue;
1327
1328 if (ct_sip_parse_transport(ct, *dptr, matchoff + matchlen,
1329 *datalen, &proto) == 0)
1330 continue;
1331
1332 ret = ct_sip_parse_numerical_param(ct, *dptr,
1333 matchoff + matchlen,
1334 *datalen, "expires=",
1335 NULL, NULL, &c_expires);
^^^^^^^^^
1336 if (ret < 0) {
^^^^^^^
"ret" is never negative.
1337 nf_ct_helper_log(skb, ct, "cannot parse expires");
1338 return NF_DROP;
1339 }
1340 if (c_expires == 0)
^^^^^^^^^^^^^^
On the first error path in ct_sip_parse_numerical_param(), if
ct_sip_header_search() failes then we return the original c_expires. On
the other error path we set it to zero.
1341 break;
1342 if (refresh_signalling_expectation(ct, &addr, proto, port,
1343 c_expires))
1344 return NF_ACCEPT;
1345 }
1346
regards,
dan carpenter
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