radsniff: Fix buffer overruns

Divide by the element size when checking for circular buffer wrap in
rs_response_to_pcap and rs_request_to_pcap.

The following Coverity errors were reported for the defect.

Error: OVERRUN (CWE-119):
freeradius-server-3.0.4rc2/src/main/radsniff.c:934: illegal_address:
"&request->capture[80UL]" evaluates to an address that is at byte offset
1280 of an array of 80 bytes.

Error: SIZEOF_MISMATCH (CWE-398):
freeradius-server-3.0.4rc2/src/main/radsniff.c:934:
suspicious_pointer_arithmetic: Adding "80UL /* sizeof (request->capture)
*/" to pointer "request->capture" of type "rs_capture_t [5]" is
suspicious because adding an integral value to this pointer
automatically scales that value by the size, 16 bytes, of the pointed-to
type, "rs_capture_t".  Most likely, you intended to use the number of
elements in "request->capture" rather than its size in bytes.

Error: OVERRUN (CWE-119):
freeradius-server-3.0.4rc2/src/main/radsniff.c:972: illegal_address:
"&request->capture[80UL]" evaluates to an address that is at byte offset 1280
of an array of 80 bytes.

Error: SIZEOF_MISMATCH (CWE-398):
freeradius-server-3.0.4rc2/src/main/radsniff.c:972:
suspicious_pointer_arithmetic: Adding "80UL /* sizeof (request->capture) */" to
pointer "request->capture" of type "rs_capture_t [5]" is suspicious because
adding an integral value to this pointer automatically scales that value by the
size, 16 bytes, of the pointed-to type, "rs_capture_t".  Most likely, you
intended to use the number of elements in "request->capture" rather than its
size in bytes.
dhcp: Remove unused attribute allocation

Remove unused and unfreed unknown attribute allocation to prevent memory
leak. Coverity has reported the following error for this issue.

Error: RESOURCE_LEAK (CWE-772):
freeradius-server-3.0.4rc2/src/modules/proto_dhcp/dhcp.c:956: alloc_fn: Storage is returned from allocation function "dict_attrunknown(unsigned int, unsigned int, int)".
freeradius-server-3.0.4rc2/src/lib/dict.c:2666:2: alloc_fn: Storage is returned from allocation function "malloc(size_t)".
freeradius-server-3.0.4rc2/src/lib/dict.c:2666:2: var_assign: Assigning: "da" = "malloc(148UL)".
freeradius-server-3.0.4rc2/src/lib/dict.c:2671:2: noescape: Resource "da" is not freed or pointed-to in function "memset(void *, int, size_t)".
freeradius-server-3.0.4rc2/src/lib/dict.c:2687:2: var_assign: Assigning: "p" = "da".
freeradius-server-3.0.4rc2/src/lib/dict.c:2689:2: noescape: Resource "p" is not freed or pointed-to in function "snprintf(char * restrict, size_t, char const * restrict, ...)".
freeradius-server-3.0.4rc2/src/lib/dict.c:2712:3: noescape: Resource "p" is not freed or pointed-to in function "snprintf(char * restrict, size_t, char const * restrict, ...)".
freeradius-server-3.0.4rc2/src/lib/dict.c:2718:2: noescape: Resource "p" is not freed or pointed-to in function "print_attr_oid(char *, size_t, unsigned int, int)".
freeradius-server-3.0.4rc2/src/lib/dict.c:2546:36: noescape: "print_attr_oid(char *, size_t, unsigned int, int)" does not free or save its pointer parameter "buffer".
freeradius-server-3.0.4rc2/src/lib/dict.c:2720:2: return_alloc: Returning allocated memory "da".
freeradius-server-3.0.4rc2/src/modules/proto_dhcp/dhcp.c:956: var_assign: Assigning: "da" = storage returned from "dict_attrunknown(p[0], 54U, 1)".
freeradius-server-3.0.4rc2/src/modules/proto_dhcp/dhcp.c:991: leaked_storage: Variable "da" going out of scope leaks the storage it points to.
dhcpd: Check cf_item_parse result

Check the result of cf_item_parse for error, propagating it up the
stack in dhcp_socket_parse.

Coverity has reported the following errors for this issue.

Error: CHECKED_RETURN (CWE-252):
freeradius-server-3.0.4rc2/src/modules/proto_dhcp/dhcpd.c:638: check_return: Calling function "cf_item_parse(CONF_SECTION *, char const *, int, void *, char const *)" without checking return value (as is done elsewhere 12 out of 14 times).
freeradius-server-3.0.4rc2/src/main/conffile.c:1416: example_assign: Example 1: Assigning: "ret" = return value from "cf_item_parse(cs, (variables + i).name, (variables + i).type, data, (variables + i).dflt)".
freeradius-server-3.0.4rc2/src/main/conffile.c:1417: example_checked: Example 1 (cont.): "ret" has its value checked in "ret < 0".
freeradius-server-3.0.4rc2/src/main/command.c:1569: example_assign: Example 2: Assigning: "rcode" = return value from "cf_item_parse(mi->cs, argv[1], (variables + i).type, data, argv[2])".
freeradius-server-3.0.4rc2/src/main/command.c:1570: example_checked: Example 2 (cont.): "rcode" has its value checked in "rcode < 0".
freeradius-server-3.0.4rc2/src/main/listen.c:916: example_assign: Example 3: Assigning: "rcode" = return value from "cf_item_parse(cs, "ipaddr", 14, &ipaddr, NULL)".
freeradius-server-3.0.4rc2/src/main/listen.c:917: example_checked: Example 3 (cont.): "rcode" has its value checked in "rcode < 0".
freeradius-server-3.0.4rc2/src/main/listen.c:2834: example_assign: Example 4: Assigning: "rcode" = return value from "cf_item_parse(cs, "type", 1, &listen_type, "")".
freeradius-server-3.0.4rc2/src/main/listen.c:2835: example_checked: Example 4 (cont.): "rcode" has its value checked in "rcode < 0".
freeradius-server-3.0.4rc2/src/main/radmin.c:530: example_assign: Example 5: Assigning: "rcode" = return value from "cf_item_parse(subcs, "socket", 1, &file, NULL)".
freeradius-server-3.0.4rc2/src/main/radmin.c:531: example_checked: Example 5 (cont.): "rcode" has its value checked in "rcode < 0".
freeradius-server-3.0.4rc2/src/modules/proto_dhcp/dhcpd.c:638: unchecked_value: No check of the return value of "cf_item_parse(cs, "suppress_responses", 23, &sock->suppress_responses, NULL)".

Error: CHECKED_RETURN (CWE-252):
freeradius-server-3.0.4rc2/src/modules/proto_dhcp/dhcpd.c:643: check_return: Calling function "cf_item_parse(CONF_SECTION *, char const *, int, void *, char const *)" without checking return value (as is done elsewhere 12 out of 14 times).
freeradius-server-3.0.4rc2/src/main/conffile.c:1416: example_assign: Example 1: Assigning: "ret" = return value from "cf_item_parse(cs, (variables + i).name, (variables + i).type, data, (variables + i).dflt)".
freeradius-server-3.0.4rc2/src/main/conffile.c:1417: example_checked: Example 1 (cont.): "ret" has its value checked in "ret < 0".
freeradius-server-3.0.4rc2/src/main/command.c:1569: example_assign: Example 2: Assigning: "rcode" = return value from "cf_item_parse(mi->cs, argv[1], (variables + i).type, data, argv[2])".
freeradius-server-3.0.4rc2/src/main/command.c:1570: example_checked: Example 2 (cont.): "rcode" has its value checked in "rcode < 0".
freeradius-server-3.0.4rc2/src/main/listen.c:916: example_assign: Example 3: Assigning: "rcode" = return value from "cf_item_parse(cs, "ipaddr", 14, &ipaddr, NULL)".
freeradius-server-3.0.4rc2/src/main/listen.c:917: example_checked: Example 3 (cont.): "rcode" has its value checked in "rcode < 0".
freeradius-server-3.0.4rc2/src/main/listen.c:2834: example_assign: Example 4: Assigning: "rcode" = return value from "cf_item_parse(cs, "type", 1, &listen_type, "")".
freeradius-server-3.0.4rc2/src/main/listen.c:2835: example_checked: Example 4 (cont.): "rcode" has its value checked in "rcode < 0".
freeradius-server-3.0.4rc2/src/main/radmin.c:530: example_assign: Example 5: Assigning: "rcode" = return value from "cf_item_parse(subcs, "socket", 1, &file, NULL)".
freeradius-server-3.0.4rc2/src/main/radmin.c:531: example_checked: Example 5 (cont.): "rcode" has its value checked in "rcode < 0".
freeradius-server-3.0.4rc2/src/modules/proto_dhcp/dhcpd.c:643: unchecked_value: No check of the return value of "cf_item_parse(cs, "src_interface", 1, &sock->src_interface, NULL)".
dhcpclient: Verify socket timeout was set

Verify the return code of setsockopt, as it may fail, in dhcpclient.c.

Coverity has reported the following error for this issue.

Error: CHECKED_RETURN (CWE-252):
freeradius-server-3.0.4rc2/src/modules/proto_dhcp/dhcpclient.c:424:
check_return: Calling function "setsockopt(sockfd, 1, 20, (char *)&tv,
16U)" without checking return value. This library function may fail and
return an error code.
freeradius-server-3.0.4rc2/src/modules/proto_dhcp/dhcpclient.c:424:
unchecked_value: No check of the return value of "setsockopt(sockfd, 1,
20, (char *)&tv, 16U)".
listen: Retrieve configuration pairs once

Retrieve configuration pairs with cf_pair_find only once, before
checking their existence, in common_socket_parse. This avoids ambiguity
confusing Coverity, which otherwise reports the following issue.

Error: NULL_RETURNS (CWE-476):
freeradius-server-3.0.4rc2/src/main/listen.c:1139: returned_null: Function "cf_pair_find(CONF_SECTION const *, char const *)" returns null (checked 51 out of 54 times).
freeradius-server-3.0.4rc2/src/main/conffile.c:2353:20: return_null: Explicitly returning null.
freeradius-server-3.0.4rc2/src/main/client.c:514: example_checked: Example 1: "cf_pair_find(cs, "ipaddr")" has its value checked in "cf_pair_find(cs, "ipaddr")".
freeradius-server-3.0.4rc2/src/main/conffile.c:667: example_assign: Example 2: Assigning: "cp" = return value from "cf_pair_find(cs, p)".
freeradius-server-3.0.4rc2/src/main/conffile.c:668: example_checked: Example 2 (cont.): "cp" has its value checked in "cp".
freeradius-server-3.0.4rc2/src/main/command.c:1556: example_assign: Example 3: Assigning: "cp" = return value from "cf_pair_find(mi->cs, argv[1])".
freeradius-server-3.0.4rc2/src/main/command.c:1557: example_checked: Example 3 (cont.): "cp" has its value checked in "cp".
freeradius-server-3.0.4rc2/src/main/listen.c:103: example_assign: Example 4: Assigning: "cp" = return value from "cf_pair_find(request->listener->cs, fmt)".
freeradius-server-3.0.4rc2/src/main/listen.c:104: example_checked: Example 4 (cont.): "cp" has its value checked in "cp".
freeradius-server-3.0.4rc2/src/main/mainconfig.c:345: example_assign: Example 5: Assigning: "cp" = return value from "cf_pair_find(request->client->cs, fmt)".
freeradius-server-3.0.4rc2/src/main/mainconfig.c:346: example_checked: Example 5 (cont.): "cp" has its value checked in "cp".
freeradius-server-3.0.4rc2/src/main/listen.c:1139: var_assigned: Assigning: "cp" = null return value from "cf_pair_find(CONF_SECTION const *, char const *)".
freeradius-server-3.0.4rc2/src/main/listen.c:1142: dereference: Dereferencing a pointer that might be null "cp" when calling "cf_log_err_cp(CONF_PAIR const *, char const *, ...)".
freeradius-server-3.0.4rc2/src/main/conffile.c:2930:2: deref_parm: Directly dereferencing parameter "cp".
Merge pull request #787 from spbnick/coverity_fixes1

Coverity fixes part 1