Dmitry V. Levin
deb0c18871
Handle multipart netlink messages made of multiple struct nlmsghdr headers with associated payload in one byte stream. * netlink.c (fetch_nlmsghdr, print_nlmsghdr, decode_nlmsghdr_with_payload): New functions. (decode_netlink): Use them. * tests/netlink_parsing.c (send_query): Check them.
133 lines
3.7 KiB
C
133 lines
3.7 KiB
C
/*
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* Copyright (c) 2016 Fabien Siron <fabien.siron@epita.fr>
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* Copyright (c) 2016 Dmitry V. Levin <ldv@altlinux.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "defs.h"
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#include <sys/socket.h>
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#include <linux/netlink.h>
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#include "xlat/netlink_flags.h"
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#include "xlat/netlink_types.h"
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/*
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* Fetch a struct nlmsghdr from the given address.
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*/
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static bool
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fetch_nlmsghdr(struct tcb *tcp, struct nlmsghdr *nlmsghdr,
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const unsigned long addr, const unsigned long len)
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{
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if (len < sizeof(struct nlmsghdr)) {
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printstr(tcp, addr, len);
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return false;
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}
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if (umove_or_printaddr(tcp, addr, nlmsghdr))
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return false;
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return true;
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}
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static void
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print_nlmsghdr(struct tcb *tcp, const struct nlmsghdr *const nlmsghdr)
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{
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/* print the whole structure regardless of its nlmsg_len */
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tprintf("{len=%u, type=", nlmsghdr->nlmsg_len);
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printxval(netlink_types, nlmsghdr->nlmsg_type, "NLMSG_???");
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tprints(", flags=");
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printflags(netlink_flags, nlmsghdr->nlmsg_flags, "NLM_F_???");
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tprintf(", seq=%u, pid=%u}", nlmsghdr->nlmsg_seq,
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nlmsghdr->nlmsg_pid);
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}
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static void
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decode_nlmsghdr_with_payload(struct tcb *tcp,
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const struct nlmsghdr *const nlmsghdr,
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const unsigned long addr,
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const unsigned long len)
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{
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tprints("{");
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print_nlmsghdr(tcp, nlmsghdr);
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unsigned long nlmsg_len =
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nlmsghdr->nlmsg_len > len ? len : nlmsghdr->nlmsg_len;
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if (nlmsg_len > sizeof(struct nlmsghdr)) {
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tprints(", ");
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printstr(tcp, addr + sizeof(struct nlmsghdr),
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nlmsg_len - sizeof(struct nlmsghdr));
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}
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tprints("}");
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}
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void
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decode_netlink(struct tcb *tcp, unsigned long addr, unsigned long len)
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{
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struct nlmsghdr nlmsghdr;
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bool print_array = false;
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unsigned int elt;
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for (elt = 0; fetch_nlmsghdr(tcp, &nlmsghdr, addr, len); elt++) {
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if (abbrev(tcp) && elt == max_strlen) {
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tprints("...");
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break;
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}
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unsigned long nlmsg_len = NLMSG_ALIGN(nlmsghdr.nlmsg_len);
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unsigned long next_addr = 0, next_len = 0;
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if (nlmsghdr.nlmsg_len >= sizeof(struct nlmsghdr)) {
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next_len = (len >= nlmsg_len) ? len - nlmsg_len : 0;
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if (next_len && addr + nlmsg_len > addr)
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next_addr = addr + nlmsg_len;
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}
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if (!print_array && next_addr) {
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tprints("[");
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print_array = true;
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}
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decode_nlmsghdr_with_payload(tcp, &nlmsghdr, addr, len);
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if (!next_addr)
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break;
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tprints(", ");
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addr = next_addr;
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len = next_len;
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}
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if (print_array) {
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tprints("]");
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}
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}
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