granicus.if.org Git - strace/blob - netlink_netfilter.c

   1 /*
   2  * Copyright (c) 2018 Chen Jingpiao <chenjingpiao@gmail.com>
   3  * Copyright (c) 2018 The strace developers.
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote products
  15  *    derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include "defs.h"
  30
  31 #ifdef HAVE_LINUX_NETFILTER_NFNETLINK_H
  32
  33 # include "print_fields.h"
  34 # include "nlattr.h"
  35
  36 # include <netinet/in.h>
  37 # include <arpa/inet.h>
  38 # include "netlink.h"
  39 # include <linux/netfilter/nfnetlink.h>
  40
  41 # include "xlat/netfilter_versions.h"
  42 # include "xlat/nl_netfilter_msg_types.h"
  43 # include "xlat/nl_netfilter_subsys_ids.h"
  44
  45 bool
  46 decode_netlink_netfilter(struct tcb *const tcp,
  47                          const struct nlmsghdr *const nlmsghdr,
  48                          const kernel_ulong_t addr,
  49                          const unsigned int len)
  50 {
  51         if (nlmsghdr->nlmsg_type == NLMSG_DONE)
  52                 return false;
  53
  54         struct nfgenmsg nfmsg;
  55
  56         if (len < sizeof(nfmsg))
  57                 printstr_ex(tcp, addr, len, QUOTE_FORCE_HEX);
  58         else if (!umove_or_printaddr(tcp, addr, &nfmsg)) {
  59                 const uint8_t subsys_id = (uint8_t) (nlmsghdr->nlmsg_type >> 8);
  60                 uint16_t res_id = ntohs(nfmsg.res_id);
  61
  62                 PRINT_FIELD_XVAL("{", nfmsg, nfgen_family, addrfams, "AF_???");
  63                 PRINT_FIELD_XVAL(", ", nfmsg, version, netfilter_versions,
  64                                  "NFNETLINK_???");
  65
  66                 /*
  67                  * Work around wrong endianness in res_id field,
  68                  * see linux commit v4.3-rc1~28^2~47^2~1
  69                  */
  70                 tprints(", res_id=");
  71                 if (subsys_id == NFNL_SUBSYS_NFTABLES
  72                     && res_id == NFNL_SUBSYS_NFTABLES) {
  73                         tprints("htons(NFNL_SUBSYS_NFTABLES)");
  74                 } else if (subsys_id == NFNL_SUBSYS_NFTABLES
  75                            && nfmsg.res_id == NFNL_SUBSYS_NFTABLES) {
  76                         tprints("NFNL_SUBSYS_NFTABLES");
  77                 } else {
  78                         tprintf("htons(%d)", res_id);
  79                 }
  80
  81                 const size_t offset = NLMSG_ALIGN(sizeof(nfmsg));
  82                 if (len > offset) {
  83                         tprints(", ");
  84                         if ((nlmsghdr->nlmsg_type >= NFNL_MSG_BATCH_BEGIN
  85                              && nlmsghdr->nlmsg_type <= NFNL_MSG_BATCH_END)
  86                             || nlmsghdr->nlmsg_type < NLMSG_MIN_TYPE)
  87                                 printstr_ex(tcp, addr + offset,
  88                                             len - offset, QUOTE_FORCE_HEX);
  89                         else
  90                                 decode_nlattr(tcp, addr + offset, len - offset,
  91                                               NULL, NULL, NULL, 0, NULL);
  92                 }
  93         }
  94
  95         return true;
  96 }
  97
  98 #endif /* HAVE_LINUX_NETFILTER_NFNETLINK_H */