Reported by: glebius Reported by: syzbot+981c528ccb5c5534dffc@syzkaller.appspotmail.com Reviewed by: tuexen, glebius MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D38936
1172 lines
32 KiB
C
1172 lines
32 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1982, 1986, 1988, 1993
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* The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_inet.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/protosw.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/sysctl.h>
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#include <sys/syslog.h>
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#include <net/if.h>
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#include <net/if_var.h>
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#include <net/if_private.h>
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#include <net/if_types.h>
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#include <net/route.h>
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#include <net/route/route_ctl.h>
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#include <net/route/nhop.h>
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#include <net/vnet.h>
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#include <netinet/in.h>
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#include <netinet/in_fib.h>
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#include <netinet/in_pcb.h>
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#include <netinet/in_systm.h>
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#include <netinet/in_var.h>
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#include <netinet/ip.h>
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#include <netinet/ip_icmp.h>
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#include <netinet/ip_var.h>
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#include <netinet/ip_options.h>
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#include <netinet/sctp.h>
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#include <netinet/tcp.h>
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#include <netinet/tcpip.h>
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#include <netinet/icmp_var.h>
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#ifdef INET
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#include <machine/in_cksum.h>
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#include <security/mac/mac_framework.h>
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#endif /* INET */
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extern ipproto_ctlinput_t *ip_ctlprotox[];
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/*
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* ICMP routines: error generation, receive packet processing, and
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* routines to turnaround packets back to the originator, and
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* host table maintenance routines.
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*/
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VNET_DEFINE_STATIC(int, icmplim) = 200;
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#define V_icmplim VNET(icmplim)
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SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(icmplim), 0,
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"Maximum number of ICMP responses per second");
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VNET_DEFINE_STATIC(int, icmplim_curr_jitter) = 0;
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#define V_icmplim_curr_jitter VNET(icmplim_curr_jitter)
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VNET_DEFINE_STATIC(int, icmplim_jitter) = 16;
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#define V_icmplim_jitter VNET(icmplim_jitter)
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_jitter, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(icmplim_jitter), 0,
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"Random icmplim jitter adjustment limit");
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VNET_DEFINE_STATIC(int, icmplim_output) = 1;
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#define V_icmplim_output VNET(icmplim_output)
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(icmplim_output), 0,
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"Enable logging of ICMP response rate limiting");
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#ifdef INET
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VNET_PCPUSTAT_DEFINE(struct icmpstat, icmpstat);
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VNET_PCPUSTAT_SYSINIT(icmpstat);
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SYSCTL_VNET_PCPUSTAT(_net_inet_icmp, ICMPCTL_STATS, stats, struct icmpstat,
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icmpstat, "ICMP statistics (struct icmpstat, netinet/icmp_var.h)");
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#ifdef VIMAGE
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VNET_PCPUSTAT_SYSUNINIT(icmpstat);
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#endif /* VIMAGE */
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VNET_DEFINE_STATIC(int, icmpmaskrepl) = 0;
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#define V_icmpmaskrepl VNET(icmpmaskrepl)
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SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(icmpmaskrepl), 0,
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"Reply to ICMP Address Mask Request packets");
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VNET_DEFINE_STATIC(u_int, icmpmaskfake) = 0;
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#define V_icmpmaskfake VNET(icmpmaskfake)
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SYSCTL_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(icmpmaskfake), 0,
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"Fake reply to ICMP Address Mask Request packets");
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VNET_DEFINE(int, drop_redirect) = 0;
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#define V_drop_redirect VNET(drop_redirect)
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(drop_redirect), 0,
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"Ignore ICMP redirects");
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VNET_DEFINE_STATIC(int, log_redirect) = 0;
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#define V_log_redirect VNET(log_redirect)
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(log_redirect), 0,
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"Log ICMP redirects to the console");
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VNET_DEFINE_STATIC(int, redirtimeout) = 60 * 10; /* 10 minutes */
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#define V_redirtimeout VNET(redirtimeout)
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, redirtimeout, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(redirtimeout), 0,
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"Delay in seconds before expiring redirect route");
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VNET_DEFINE_STATIC(char, reply_src[IFNAMSIZ]);
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#define V_reply_src VNET(reply_src)
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SYSCTL_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(reply_src), IFNAMSIZ,
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"ICMP reply source for non-local packets");
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VNET_DEFINE_STATIC(int, icmp_rfi) = 0;
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#define V_icmp_rfi VNET(icmp_rfi)
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(icmp_rfi), 0,
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"ICMP reply from incoming interface for non-local packets");
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/* Router requirements RFC 1812 section 4.3.2.3 requires 576 - 28. */
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VNET_DEFINE_STATIC(int, icmp_quotelen) = 548;
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#define V_icmp_quotelen VNET(icmp_quotelen)
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(icmp_quotelen), 0,
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"Number of bytes from original packet to quote in ICMP reply");
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VNET_DEFINE_STATIC(int, icmpbmcastecho) = 0;
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#define V_icmpbmcastecho VNET(icmpbmcastecho)
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(icmpbmcastecho), 0,
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"Reply to multicast ICMP Echo Request and Timestamp packets");
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VNET_DEFINE_STATIC(int, icmptstamprepl) = 1;
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#define V_icmptstamprepl VNET(icmptstamprepl)
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, tstamprepl, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(icmptstamprepl), 0,
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"Respond to ICMP Timestamp packets");
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VNET_DEFINE_STATIC(int, error_keeptags) = 0;
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#define V_error_keeptags VNET(error_keeptags)
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SYSCTL_INT(_net_inet_icmp, OID_AUTO, error_keeptags, CTLFLAG_VNET | CTLFLAG_RW,
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&VNET_NAME(error_keeptags), 0,
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"ICMP error response keeps copy of mbuf_tags of original packet");
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#ifdef ICMPPRINTFS
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int icmpprintfs = 0;
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#endif
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static void icmp_reflect(struct mbuf *);
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static void icmp_send(struct mbuf *, struct mbuf *);
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static int icmp_verify_redirect_gateway(struct sockaddr_in *,
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struct sockaddr_in *, struct sockaddr_in *, u_int);
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/*
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* Kernel module interface for updating icmpstat. The argument is an index
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* into icmpstat treated as an array of u_long. While this encodes the
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* general layout of icmpstat into the caller, it doesn't encode its
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* location, so that future changes to add, for example, per-CPU stats
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* support won't cause binary compatibility problems for kernel modules.
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*/
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void
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kmod_icmpstat_inc(int statnum)
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{
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counter_u64_add(VNET(icmpstat)[statnum], 1);
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}
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/*
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* Generate an error packet of type error
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* in response to bad packet ip.
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*/
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void
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icmp_error(struct mbuf *n, int type, int code, uint32_t dest, int mtu)
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{
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struct ip *oip, *nip;
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struct icmp *icp;
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struct mbuf *m;
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unsigned icmplen, icmpelen, nlen, oiphlen;
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KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type",
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__func__));
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if (type != ICMP_REDIRECT)
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ICMPSTAT_INC(icps_error);
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/*
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* Don't send error:
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* if the original packet was encrypted.
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* if not the first fragment of message.
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* in response to a multicast or broadcast packet.
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* if the old packet protocol was an ICMP error message.
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*/
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if (n->m_flags & M_DECRYPTED)
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goto freeit;
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if (n->m_flags & (M_BCAST|M_MCAST))
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goto freeit;
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/* Drop if IP header plus 8 bytes is not contiguous in first mbuf. */
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if (n->m_len < sizeof(struct ip) + ICMP_MINLEN)
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goto freeit;
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oip = mtod(n, struct ip *);
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oiphlen = oip->ip_hl << 2;
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if (n->m_len < oiphlen + ICMP_MINLEN)
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goto freeit;
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#ifdef ICMPPRINTFS
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if (icmpprintfs)
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printf("icmp_error(%p, %x, %d)\n", oip, type, code);
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#endif
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if (oip->ip_off & htons(~(IP_MF|IP_DF)))
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goto freeit;
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if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
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!ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip +
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oiphlen))->icmp_type)) {
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ICMPSTAT_INC(icps_oldicmp);
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goto freeit;
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}
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/*
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* Calculate length to quote from original packet and
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* prevent the ICMP mbuf from overflowing.
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* Unfortunately this is non-trivial since ip_forward()
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* sends us truncated packets.
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*/
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nlen = m_length(n, NULL);
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if (oip->ip_p == IPPROTO_TCP) {
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struct tcphdr *th;
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int tcphlen;
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if (oiphlen + sizeof(struct tcphdr) > n->m_len &&
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n->m_next == NULL)
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goto stdreply;
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if (n->m_len < oiphlen + sizeof(struct tcphdr) &&
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(n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL)
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goto freeit;
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oip = mtod(n, struct ip *);
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th = mtodo(n, oiphlen);
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tcphlen = th->th_off << 2;
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if (tcphlen < sizeof(struct tcphdr))
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goto freeit;
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if (ntohs(oip->ip_len) < oiphlen + tcphlen)
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goto freeit;
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if (oiphlen + tcphlen > n->m_len && n->m_next == NULL)
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goto stdreply;
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if (n->m_len < oiphlen + tcphlen &&
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(n = m_pullup(n, oiphlen + tcphlen)) == NULL)
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goto freeit;
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oip = mtod(n, struct ip *);
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icmpelen = max(tcphlen, min(V_icmp_quotelen,
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ntohs(oip->ip_len) - oiphlen));
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} else if (oip->ip_p == IPPROTO_SCTP) {
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struct sctphdr *sh;
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struct sctp_chunkhdr *ch;
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if (ntohs(oip->ip_len) < oiphlen + sizeof(struct sctphdr))
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goto stdreply;
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if (oiphlen + sizeof(struct sctphdr) > n->m_len &&
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n->m_next == NULL)
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goto stdreply;
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if (n->m_len < oiphlen + sizeof(struct sctphdr) &&
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(n = m_pullup(n, oiphlen + sizeof(struct sctphdr))) == NULL)
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goto freeit;
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oip = mtod(n, struct ip *);
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icmpelen = max(sizeof(struct sctphdr),
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min(V_icmp_quotelen, ntohs(oip->ip_len) - oiphlen));
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sh = mtodo(n, oiphlen);
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if (ntohl(sh->v_tag) == 0 &&
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ntohs(oip->ip_len) >= oiphlen +
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sizeof(struct sctphdr) + 8 &&
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(n->m_len >= oiphlen + sizeof(struct sctphdr) + 8 ||
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n->m_next != NULL)) {
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if (n->m_len < oiphlen + sizeof(struct sctphdr) + 8 &&
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(n = m_pullup(n, oiphlen +
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sizeof(struct sctphdr) + 8)) == NULL)
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goto freeit;
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oip = mtod(n, struct ip *);
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sh = mtodo(n, oiphlen);
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ch = (struct sctp_chunkhdr *)(sh + 1);
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if (ch->chunk_type == SCTP_INITIATION) {
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icmpelen = max(sizeof(struct sctphdr) + 8,
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min(V_icmp_quotelen, ntohs(oip->ip_len) -
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oiphlen));
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}
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}
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} else
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stdreply: icmpelen = max(8, min(V_icmp_quotelen, ntohs(oip->ip_len) -
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oiphlen));
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icmplen = min(oiphlen + icmpelen, nlen);
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if (icmplen < sizeof(struct ip))
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goto freeit;
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if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen)
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m = m_gethdr(M_NOWAIT, MT_DATA);
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else
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m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
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if (m == NULL)
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goto freeit;
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#ifdef MAC
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mac_netinet_icmp_reply(n, m);
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#endif
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icmplen = min(icmplen, M_TRAILINGSPACE(m) -
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sizeof(struct ip) - ICMP_MINLEN);
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m_align(m, sizeof(struct ip) + ICMP_MINLEN + icmplen);
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m->m_data += sizeof(struct ip);
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m->m_len = ICMP_MINLEN + icmplen;
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/* XXX MRT make the outgoing packet use the same FIB
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* that was associated with the incoming packet
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*/
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M_SETFIB(m, M_GETFIB(n));
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icp = mtod(m, struct icmp *);
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ICMPSTAT_INC(icps_outhist[type]);
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icp->icmp_type = type;
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if (type == ICMP_REDIRECT)
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icp->icmp_gwaddr.s_addr = dest;
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else {
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icp->icmp_void = 0;
|
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/*
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* The following assignments assume an overlay with the
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* just zeroed icmp_void field.
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*/
|
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if (type == ICMP_PARAMPROB) {
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icp->icmp_pptr = code;
|
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code = 0;
|
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} else if (type == ICMP_UNREACH &&
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code == ICMP_UNREACH_NEEDFRAG && mtu) {
|
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icp->icmp_nextmtu = htons(mtu);
|
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}
|
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}
|
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icp->icmp_code = code;
|
|
|
|
/*
|
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* Copy the quotation into ICMP message and
|
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* convert quoted IP header back to network representation.
|
|
*/
|
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m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
|
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nip = &icp->icmp_ip;
|
|
|
|
/*
|
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* Set up ICMP message mbuf and copy old IP header (without options
|
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* in front of ICMP message.
|
|
* If the original mbuf was meant to bypass the firewall, the error
|
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* reply should bypass as well.
|
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*/
|
|
m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
|
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KASSERT(M_LEADINGSPACE(m) >= sizeof(struct ip),
|
|
("insufficient space for ip header"));
|
|
m->m_data -= sizeof(struct ip);
|
|
m->m_len += sizeof(struct ip);
|
|
m->m_pkthdr.len = m->m_len;
|
|
m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
|
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nip = mtod(m, struct ip *);
|
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bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
|
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nip->ip_len = htons(m->m_len);
|
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nip->ip_v = IPVERSION;
|
|
nip->ip_hl = 5;
|
|
nip->ip_p = IPPROTO_ICMP;
|
|
nip->ip_tos = 0;
|
|
nip->ip_off = 0;
|
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|
|
if (V_error_keeptags)
|
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m_tag_copy_chain(m, n, M_NOWAIT);
|
|
|
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icmp_reflect(m);
|
|
|
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freeit:
|
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m_freem(n);
|
|
}
|
|
|
|
int
|
|
icmp_errmap(const struct icmp *icp)
|
|
{
|
|
|
|
switch (icp->icmp_type) {
|
|
case ICMP_UNREACH:
|
|
switch (icp->icmp_code) {
|
|
case ICMP_UNREACH_NET:
|
|
case ICMP_UNREACH_HOST:
|
|
case ICMP_UNREACH_SRCFAIL:
|
|
case ICMP_UNREACH_NET_UNKNOWN:
|
|
case ICMP_UNREACH_HOST_UNKNOWN:
|
|
case ICMP_UNREACH_ISOLATED:
|
|
case ICMP_UNREACH_TOSNET:
|
|
case ICMP_UNREACH_TOSHOST:
|
|
case ICMP_UNREACH_HOST_PRECEDENCE:
|
|
case ICMP_UNREACH_PRECEDENCE_CUTOFF:
|
|
return (EHOSTUNREACH);
|
|
case ICMP_UNREACH_NEEDFRAG:
|
|
return (EMSGSIZE);
|
|
case ICMP_UNREACH_PROTOCOL:
|
|
case ICMP_UNREACH_PORT:
|
|
case ICMP_UNREACH_NET_PROHIB:
|
|
case ICMP_UNREACH_HOST_PROHIB:
|
|
case ICMP_UNREACH_FILTER_PROHIB:
|
|
return (ECONNREFUSED);
|
|
default:
|
|
return (0);
|
|
}
|
|
case ICMP_TIMXCEED:
|
|
switch (icp->icmp_code) {
|
|
case ICMP_TIMXCEED_INTRANS:
|
|
return (EHOSTUNREACH);
|
|
default:
|
|
return (0);
|
|
}
|
|
case ICMP_PARAMPROB:
|
|
switch (icp->icmp_code) {
|
|
case ICMP_PARAMPROB_ERRATPTR:
|
|
case ICMP_PARAMPROB_OPTABSENT:
|
|
return (ENOPROTOOPT);
|
|
default:
|
|
return (0);
|
|
}
|
|
default:
|
|
return (0);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Process a received ICMP message.
|
|
*/
|
|
int
|
|
icmp_input(struct mbuf **mp, int *offp, int proto)
|
|
{
|
|
struct icmp *icp;
|
|
struct in_ifaddr *ia;
|
|
struct mbuf *m = *mp;
|
|
struct ip *ip = mtod(m, struct ip *);
|
|
struct sockaddr_in icmpsrc, icmpdst, icmpgw;
|
|
int hlen = *offp;
|
|
int icmplen = ntohs(ip->ip_len) - *offp;
|
|
int i, code;
|
|
int fibnum;
|
|
|
|
NET_EPOCH_ASSERT();
|
|
|
|
*mp = NULL;
|
|
|
|
/*
|
|
* Locate icmp structure in mbuf, and check
|
|
* that not corrupted and of at least minimum length.
|
|
*/
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs) {
|
|
char srcbuf[INET_ADDRSTRLEN];
|
|
char dstbuf[INET_ADDRSTRLEN];
|
|
|
|
printf("icmp_input from %s to %s, len %d\n",
|
|
inet_ntoa_r(ip->ip_src, srcbuf),
|
|
inet_ntoa_r(ip->ip_dst, dstbuf), icmplen);
|
|
}
|
|
#endif
|
|
if (icmplen < ICMP_MINLEN) {
|
|
ICMPSTAT_INC(icps_tooshort);
|
|
goto freeit;
|
|
}
|
|
i = hlen + min(icmplen, ICMP_ADVLENMIN);
|
|
if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
|
|
ICMPSTAT_INC(icps_tooshort);
|
|
return (IPPROTO_DONE);
|
|
}
|
|
ip = mtod(m, struct ip *);
|
|
m->m_len -= hlen;
|
|
m->m_data += hlen;
|
|
icp = mtod(m, struct icmp *);
|
|
if (in_cksum(m, icmplen)) {
|
|
ICMPSTAT_INC(icps_checksum);
|
|
goto freeit;
|
|
}
|
|
m->m_len += hlen;
|
|
m->m_data -= hlen;
|
|
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs)
|
|
printf("icmp_input, type %d code %d\n", icp->icmp_type,
|
|
icp->icmp_code);
|
|
#endif
|
|
|
|
/*
|
|
* Message type specific processing.
|
|
*/
|
|
if (icp->icmp_type > ICMP_MAXTYPE)
|
|
goto raw;
|
|
|
|
/* Initialize */
|
|
bzero(&icmpsrc, sizeof(icmpsrc));
|
|
icmpsrc.sin_len = sizeof(struct sockaddr_in);
|
|
icmpsrc.sin_family = AF_INET;
|
|
bzero(&icmpdst, sizeof(icmpdst));
|
|
icmpdst.sin_len = sizeof(struct sockaddr_in);
|
|
icmpdst.sin_family = AF_INET;
|
|
bzero(&icmpgw, sizeof(icmpgw));
|
|
icmpgw.sin_len = sizeof(struct sockaddr_in);
|
|
icmpgw.sin_family = AF_INET;
|
|
|
|
ICMPSTAT_INC(icps_inhist[icp->icmp_type]);
|
|
code = icp->icmp_code;
|
|
switch (icp->icmp_type) {
|
|
case ICMP_UNREACH:
|
|
if (code > ICMP_UNREACH_PRECEDENCE_CUTOFF)
|
|
goto badcode;
|
|
else
|
|
goto deliver;
|
|
|
|
case ICMP_TIMXCEED:
|
|
if (code > ICMP_TIMXCEED_REASS)
|
|
goto badcode;
|
|
else
|
|
goto deliver;
|
|
|
|
case ICMP_PARAMPROB:
|
|
if (code > ICMP_PARAMPROB_LENGTH)
|
|
goto badcode;
|
|
|
|
deliver:
|
|
/*
|
|
* Problem with datagram; advise higher level routines.
|
|
*/
|
|
if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
|
|
icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
|
|
ICMPSTAT_INC(icps_badlen);
|
|
goto freeit;
|
|
}
|
|
/* Discard ICMP's in response to multicast packets */
|
|
if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
|
|
goto badcode;
|
|
/* Filter out responses to INADDR_ANY, protocols ignore it. */
|
|
if (icp->icmp_ip.ip_dst.s_addr == INADDR_ANY ||
|
|
icp->icmp_ip.ip_src.s_addr == INADDR_ANY)
|
|
goto freeit;
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs)
|
|
printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
|
|
#endif
|
|
/*
|
|
* XXX if the packet contains [IPv4 AH TCP], we can't make a
|
|
* notification to TCP layer.
|
|
*/
|
|
i = sizeof(struct ip) + min(icmplen, ICMP_ADVLENPREF(icp));
|
|
ip_stripoptions(m);
|
|
if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
|
|
/* This should actually not happen */
|
|
ICMPSTAT_INC(icps_tooshort);
|
|
return (IPPROTO_DONE);
|
|
}
|
|
ip = mtod(m, struct ip *);
|
|
icp = (struct icmp *)(ip + 1);
|
|
/*
|
|
* The upper layer handler can rely on:
|
|
* - The outer IP header has no options.
|
|
* - The outer IP header, the ICMP header, the inner IP header,
|
|
* and the first n bytes of the inner payload are contiguous.
|
|
* n is at least 8, but might be larger based on
|
|
* ICMP_ADVLENPREF. See its definition in ip_icmp.h.
|
|
*/
|
|
if (ip_ctlprotox[icp->icmp_ip.ip_p] != NULL)
|
|
ip_ctlprotox[icp->icmp_ip.ip_p](icp);
|
|
break;
|
|
|
|
badcode:
|
|
ICMPSTAT_INC(icps_badcode);
|
|
break;
|
|
|
|
case ICMP_ECHO:
|
|
if (!V_icmpbmcastecho
|
|
&& (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
|
|
ICMPSTAT_INC(icps_bmcastecho);
|
|
break;
|
|
}
|
|
if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
|
|
goto freeit;
|
|
icp->icmp_type = ICMP_ECHOREPLY;
|
|
goto reflect;
|
|
|
|
case ICMP_TSTAMP:
|
|
if (V_icmptstamprepl == 0)
|
|
break;
|
|
if (!V_icmpbmcastecho
|
|
&& (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
|
|
ICMPSTAT_INC(icps_bmcasttstamp);
|
|
break;
|
|
}
|
|
if (icmplen < ICMP_TSLEN) {
|
|
ICMPSTAT_INC(icps_badlen);
|
|
break;
|
|
}
|
|
if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
|
|
goto freeit;
|
|
icp->icmp_type = ICMP_TSTAMPREPLY;
|
|
icp->icmp_rtime = iptime();
|
|
icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
|
|
goto reflect;
|
|
|
|
case ICMP_MASKREQ:
|
|
if (V_icmpmaskrepl == 0)
|
|
break;
|
|
/*
|
|
* We are not able to respond with all ones broadcast
|
|
* unless we receive it over a point-to-point interface.
|
|
*/
|
|
if (icmplen < ICMP_MASKLEN)
|
|
break;
|
|
switch (ip->ip_dst.s_addr) {
|
|
case INADDR_BROADCAST:
|
|
case INADDR_ANY:
|
|
icmpdst.sin_addr = ip->ip_src;
|
|
break;
|
|
|
|
default:
|
|
icmpdst.sin_addr = ip->ip_dst;
|
|
}
|
|
ia = (struct in_ifaddr *)ifaof_ifpforaddr(
|
|
(struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
|
|
if (ia == NULL)
|
|
break;
|
|
if (ia->ia_ifp == NULL)
|
|
break;
|
|
icp->icmp_type = ICMP_MASKREPLY;
|
|
if (V_icmpmaskfake == 0)
|
|
icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
|
|
else
|
|
icp->icmp_mask = V_icmpmaskfake;
|
|
if (ip->ip_src.s_addr == 0) {
|
|
if (ia->ia_ifp->if_flags & IFF_BROADCAST)
|
|
ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
|
|
else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
|
|
ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
|
|
}
|
|
reflect:
|
|
ICMPSTAT_INC(icps_reflect);
|
|
ICMPSTAT_INC(icps_outhist[icp->icmp_type]);
|
|
icmp_reflect(m);
|
|
return (IPPROTO_DONE);
|
|
|
|
case ICMP_REDIRECT:
|
|
if (V_log_redirect) {
|
|
u_long src, dst, gw;
|
|
|
|
src = ntohl(ip->ip_src.s_addr);
|
|
dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
|
|
gw = ntohl(icp->icmp_gwaddr.s_addr);
|
|
printf("icmp redirect from %d.%d.%d.%d: "
|
|
"%d.%d.%d.%d => %d.%d.%d.%d\n",
|
|
(int)(src >> 24), (int)((src >> 16) & 0xff),
|
|
(int)((src >> 8) & 0xff), (int)(src & 0xff),
|
|
(int)(dst >> 24), (int)((dst >> 16) & 0xff),
|
|
(int)((dst >> 8) & 0xff), (int)(dst & 0xff),
|
|
(int)(gw >> 24), (int)((gw >> 16) & 0xff),
|
|
(int)((gw >> 8) & 0xff), (int)(gw & 0xff));
|
|
}
|
|
/*
|
|
* RFC1812 says we must ignore ICMP redirects if we
|
|
* are acting as router.
|
|
*/
|
|
if (V_drop_redirect || V_ipforwarding)
|
|
break;
|
|
if (code > 3)
|
|
goto badcode;
|
|
if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
|
|
icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
|
|
ICMPSTAT_INC(icps_badlen);
|
|
break;
|
|
}
|
|
/*
|
|
* Short circuit routing redirects to force
|
|
* immediate change in the kernel's routing
|
|
* tables. The message is also handed to anyone
|
|
* listening on a raw socket (e.g. the routing
|
|
* daemon for use in updating its tables).
|
|
*/
|
|
icmpgw.sin_addr = ip->ip_src;
|
|
icmpdst.sin_addr = icp->icmp_gwaddr;
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs) {
|
|
char dstbuf[INET_ADDRSTRLEN];
|
|
char gwbuf[INET_ADDRSTRLEN];
|
|
|
|
printf("redirect dst %s to %s\n",
|
|
inet_ntoa_r(icp->icmp_ip.ip_dst, dstbuf),
|
|
inet_ntoa_r(icp->icmp_gwaddr, gwbuf));
|
|
}
|
|
#endif
|
|
icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
|
|
|
|
/*
|
|
* RFC 1122 says network (code 0,2) redirects SHOULD
|
|
* be treated identically to the host redirects.
|
|
* Given that, ignore network masks.
|
|
*/
|
|
|
|
/*
|
|
* Variable values:
|
|
* icmpsrc: route destination
|
|
* icmpdst: route gateway
|
|
* icmpgw: message source
|
|
*/
|
|
|
|
if (icmp_verify_redirect_gateway(&icmpgw, &icmpsrc, &icmpdst,
|
|
M_GETFIB(m)) != 0) {
|
|
/* TODO: increment bad redirects here */
|
|
break;
|
|
}
|
|
|
|
for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
|
|
rib_add_redirect(fibnum, (struct sockaddr *)&icmpsrc,
|
|
(struct sockaddr *)&icmpdst,
|
|
(struct sockaddr *)&icmpgw, m->m_pkthdr.rcvif,
|
|
RTF_GATEWAY, V_redirtimeout);
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* No kernel processing for the following;
|
|
* just fall through to send to raw listener.
|
|
*/
|
|
case ICMP_ECHOREPLY:
|
|
case ICMP_ROUTERADVERT:
|
|
case ICMP_ROUTERSOLICIT:
|
|
case ICMP_TSTAMPREPLY:
|
|
case ICMP_IREQREPLY:
|
|
case ICMP_MASKREPLY:
|
|
case ICMP_SOURCEQUENCH:
|
|
default:
|
|
break;
|
|
}
|
|
|
|
raw:
|
|
*mp = m;
|
|
rip_input(mp, offp, proto);
|
|
return (IPPROTO_DONE);
|
|
|
|
freeit:
|
|
m_freem(m);
|
|
return (IPPROTO_DONE);
|
|
}
|
|
|
|
/*
|
|
* Reflect the ip packet back to the source
|
|
*/
|
|
static void
|
|
icmp_reflect(struct mbuf *m)
|
|
{
|
|
struct ip *ip = mtod(m, struct ip *);
|
|
struct ifaddr *ifa;
|
|
struct ifnet *ifp;
|
|
struct in_ifaddr *ia;
|
|
struct in_addr t;
|
|
struct nhop_object *nh;
|
|
struct mbuf *opts = NULL;
|
|
int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
|
|
|
|
NET_EPOCH_ASSERT();
|
|
|
|
if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
|
|
(IN_EXPERIMENTAL(ntohl(ip->ip_src.s_addr)) && !V_ip_allow_net240) ||
|
|
(IN_ZERONET(ntohl(ip->ip_src.s_addr)) && !V_ip_allow_net0) ) {
|
|
m_freem(m); /* Bad return address */
|
|
ICMPSTAT_INC(icps_badaddr);
|
|
goto done; /* Ip_output() will check for broadcast */
|
|
}
|
|
|
|
t = ip->ip_dst;
|
|
ip->ip_dst = ip->ip_src;
|
|
|
|
/*
|
|
* Source selection for ICMP replies:
|
|
*
|
|
* If the incoming packet was addressed directly to one of our
|
|
* own addresses, use dst as the src for the reply.
|
|
*/
|
|
CK_LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) {
|
|
if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) {
|
|
t = IA_SIN(ia)->sin_addr;
|
|
goto match;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If the incoming packet was addressed to one of our broadcast
|
|
* addresses, use the first non-broadcast address which corresponds
|
|
* to the incoming interface.
|
|
*/
|
|
ifp = m->m_pkthdr.rcvif;
|
|
if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
|
|
CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
|
|
if (ifa->ifa_addr->sa_family != AF_INET)
|
|
continue;
|
|
ia = ifatoia(ifa);
|
|
if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
|
|
t.s_addr) {
|
|
t = IA_SIN(ia)->sin_addr;
|
|
goto match;
|
|
}
|
|
}
|
|
}
|
|
/*
|
|
* If the packet was transiting through us, use the address of
|
|
* the interface the packet came through in. If that interface
|
|
* doesn't have a suitable IP address, the normal selection
|
|
* criteria apply.
|
|
*/
|
|
if (V_icmp_rfi && ifp != NULL) {
|
|
CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
|
|
if (ifa->ifa_addr->sa_family != AF_INET)
|
|
continue;
|
|
ia = ifatoia(ifa);
|
|
t = IA_SIN(ia)->sin_addr;
|
|
goto match;
|
|
}
|
|
}
|
|
/*
|
|
* If the incoming packet was not addressed directly to us, use
|
|
* designated interface for icmp replies specified by sysctl
|
|
* net.inet.icmp.reply_src (default not set). Otherwise continue
|
|
* with normal source selection.
|
|
*/
|
|
if (V_reply_src[0] != '\0' && (ifp = ifunit(V_reply_src))) {
|
|
CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
|
|
if (ifa->ifa_addr->sa_family != AF_INET)
|
|
continue;
|
|
ia = ifatoia(ifa);
|
|
t = IA_SIN(ia)->sin_addr;
|
|
goto match;
|
|
}
|
|
}
|
|
/*
|
|
* If the packet was transiting through us, use the address of
|
|
* the interface that is the closest to the packet source.
|
|
* When we don't have a route back to the packet source, stop here
|
|
* and drop the packet.
|
|
*/
|
|
nh = fib4_lookup(M_GETFIB(m), ip->ip_dst, 0, NHR_NONE, 0);
|
|
if (nh == NULL) {
|
|
m_freem(m);
|
|
ICMPSTAT_INC(icps_noroute);
|
|
goto done;
|
|
}
|
|
t = IA_SIN(ifatoia(nh->nh_ifa))->sin_addr;
|
|
match:
|
|
#ifdef MAC
|
|
mac_netinet_icmp_replyinplace(m);
|
|
#endif
|
|
ip->ip_src = t;
|
|
ip->ip_ttl = V_ip_defttl;
|
|
|
|
if (optlen > 0) {
|
|
u_char *cp;
|
|
int opt, cnt;
|
|
u_int len;
|
|
|
|
/*
|
|
* Retrieve any source routing from the incoming packet;
|
|
* add on any record-route or timestamp options.
|
|
*/
|
|
cp = (u_char *) (ip + 1);
|
|
if ((opts = ip_srcroute(m)) == NULL &&
|
|
(opts = m_gethdr(M_NOWAIT, MT_DATA))) {
|
|
opts->m_len = sizeof(struct in_addr);
|
|
mtod(opts, struct in_addr *)->s_addr = 0;
|
|
}
|
|
if (opts) {
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs)
|
|
printf("icmp_reflect optlen %d rt %d => ",
|
|
optlen, opts->m_len);
|
|
#endif
|
|
for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
|
|
opt = cp[IPOPT_OPTVAL];
|
|
if (opt == IPOPT_EOL)
|
|
break;
|
|
if (opt == IPOPT_NOP)
|
|
len = 1;
|
|
else {
|
|
if (cnt < IPOPT_OLEN + sizeof(*cp))
|
|
break;
|
|
len = cp[IPOPT_OLEN];
|
|
if (len < IPOPT_OLEN + sizeof(*cp) ||
|
|
len > cnt)
|
|
break;
|
|
}
|
|
/*
|
|
* Should check for overflow, but it "can't happen"
|
|
*/
|
|
if (opt == IPOPT_RR || opt == IPOPT_TS ||
|
|
opt == IPOPT_SECURITY) {
|
|
bcopy((caddr_t)cp,
|
|
mtod(opts, caddr_t) + opts->m_len, len);
|
|
opts->m_len += len;
|
|
}
|
|
}
|
|
/* Terminate & pad, if necessary */
|
|
cnt = opts->m_len % 4;
|
|
if (cnt) {
|
|
for (; cnt < 4; cnt++) {
|
|
*(mtod(opts, caddr_t) + opts->m_len) =
|
|
IPOPT_EOL;
|
|
opts->m_len++;
|
|
}
|
|
}
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs)
|
|
printf("%d\n", opts->m_len);
|
|
#endif
|
|
}
|
|
ip_stripoptions(m);
|
|
}
|
|
m_tag_delete_nonpersistent(m);
|
|
m->m_flags &= ~(M_BCAST|M_MCAST);
|
|
icmp_send(m, opts);
|
|
done:
|
|
if (opts)
|
|
(void)m_free(opts);
|
|
}
|
|
|
|
/*
|
|
* Verifies if redirect message is valid, according to RFC 1122
|
|
*
|
|
* @src: sockaddr with address of redirect originator
|
|
* @dst: sockaddr with destination in question
|
|
* @gateway: new proposed gateway
|
|
*
|
|
* Returns 0 on success.
|
|
*/
|
|
static int
|
|
icmp_verify_redirect_gateway(struct sockaddr_in *src, struct sockaddr_in *dst,
|
|
struct sockaddr_in *gateway, u_int fibnum)
|
|
{
|
|
struct nhop_object *nh;
|
|
struct ifaddr *ifa;
|
|
|
|
NET_EPOCH_ASSERT();
|
|
|
|
/* Verify the gateway is directly reachable. */
|
|
if ((ifa = ifa_ifwithnet((struct sockaddr *)gateway, 0, fibnum))==NULL)
|
|
return (ENETUNREACH);
|
|
|
|
/* TODO: fib-aware. */
|
|
if (ifa_ifwithaddr_check((struct sockaddr *)gateway))
|
|
return (EHOSTUNREACH);
|
|
|
|
nh = fib4_lookup(fibnum, dst->sin_addr, 0, NHR_NONE, 0);
|
|
if (nh == NULL)
|
|
return (EINVAL);
|
|
|
|
/*
|
|
* If the redirect isn't from our current router for this dst,
|
|
* it's either old or wrong. If it redirects us to ourselves,
|
|
* we have a routing loop, perhaps as a result of an interface
|
|
* going down recently.
|
|
*/
|
|
if (!sa_equal((struct sockaddr *)src, &nh->gw_sa))
|
|
return (EINVAL);
|
|
if (nh->nh_ifa != ifa && ifa->ifa_addr->sa_family != AF_LINK)
|
|
return (EINVAL);
|
|
|
|
/* If host route already exists, ignore redirect. */
|
|
if (nh->nh_flags & NHF_HOST)
|
|
return (EEXIST);
|
|
|
|
/* If the prefix is directly reachable, ignore redirect. */
|
|
if (!(nh->nh_flags & NHF_GATEWAY))
|
|
return (EEXIST);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Send an icmp packet back to the ip level,
|
|
* after supplying a checksum.
|
|
*/
|
|
static void
|
|
icmp_send(struct mbuf *m, struct mbuf *opts)
|
|
{
|
|
struct ip *ip = mtod(m, struct ip *);
|
|
int hlen;
|
|
struct icmp *icp;
|
|
|
|
hlen = ip->ip_hl << 2;
|
|
m->m_data += hlen;
|
|
m->m_len -= hlen;
|
|
icp = mtod(m, struct icmp *);
|
|
icp->icmp_cksum = 0;
|
|
icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen);
|
|
m->m_data -= hlen;
|
|
m->m_len += hlen;
|
|
m->m_pkthdr.rcvif = (struct ifnet *)0;
|
|
#ifdef ICMPPRINTFS
|
|
if (icmpprintfs) {
|
|
char dstbuf[INET_ADDRSTRLEN];
|
|
char srcbuf[INET_ADDRSTRLEN];
|
|
|
|
printf("icmp_send dst %s src %s\n",
|
|
inet_ntoa_r(ip->ip_dst, dstbuf),
|
|
inet_ntoa_r(ip->ip_src, srcbuf));
|
|
}
|
|
#endif
|
|
(void) ip_output(m, opts, NULL, 0, NULL, NULL);
|
|
}
|
|
|
|
/*
|
|
* Return milliseconds since 00:00 UTC in network format.
|
|
*/
|
|
uint32_t
|
|
iptime(void)
|
|
{
|
|
struct timeval atv;
|
|
u_long t;
|
|
|
|
getmicrotime(&atv);
|
|
t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
|
|
return (htonl(t));
|
|
}
|
|
|
|
/*
|
|
* Return the next larger or smaller MTU plateau (table from RFC 1191)
|
|
* given current value MTU. If DIR is less than zero, a larger plateau
|
|
* is returned; otherwise, a smaller value is returned.
|
|
*/
|
|
int
|
|
ip_next_mtu(int mtu, int dir)
|
|
{
|
|
static int mtutab[] = {
|
|
65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508,
|
|
296, 68, 0
|
|
};
|
|
int i, size;
|
|
|
|
size = (sizeof mtutab) / (sizeof mtutab[0]);
|
|
if (dir >= 0) {
|
|
for (i = 0; i < size; i++)
|
|
if (mtu > mtutab[i])
|
|
return mtutab[i];
|
|
} else {
|
|
for (i = size - 1; i >= 0; i--)
|
|
if (mtu < mtutab[i])
|
|
return mtutab[i];
|
|
if (mtu == mtutab[0])
|
|
return mtutab[0];
|
|
}
|
|
return 0;
|
|
}
|
|
#endif /* INET */
|
|
|
|
/*
|
|
* badport_bandlim() - check for ICMP bandwidth limit
|
|
*
|
|
* Return 0 if it is ok to send an ICMP error response, -1 if we have
|
|
* hit our bandwidth limit and it is not ok.
|
|
*
|
|
* If icmplim is <= 0, the feature is disabled and 0 is returned.
|
|
*
|
|
* For now we separate the TCP and UDP subsystems w/ different 'which'
|
|
* values. We may eventually remove this separation (and simplify the
|
|
* code further).
|
|
*
|
|
* Note that the printing of the error message is delayed so we can
|
|
* properly print the icmp error rate that the system was trying to do
|
|
* (i.e. 22000/100 pps, etc...). This can cause long delays in printing
|
|
* the 'final' error, but it doesn't make sense to solve the printing
|
|
* delay with more complex code.
|
|
*/
|
|
struct icmp_rate {
|
|
const char *descr;
|
|
struct counter_rate cr;
|
|
};
|
|
VNET_DEFINE_STATIC(struct icmp_rate, icmp_rates[BANDLIM_MAX]) = {
|
|
{ "icmp unreach response" },
|
|
{ "icmp ping response" },
|
|
{ "icmp tstamp response" },
|
|
{ "closed port RST response" },
|
|
{ "open port RST response" },
|
|
{ "icmp6 unreach response" },
|
|
{ "sctp ootb response" }
|
|
};
|
|
#define V_icmp_rates VNET(icmp_rates)
|
|
|
|
static void
|
|
icmp_bandlimit_init(void)
|
|
{
|
|
|
|
for (int i = 0; i < BANDLIM_MAX; i++) {
|
|
V_icmp_rates[i].cr.cr_rate = counter_u64_alloc(M_WAITOK);
|
|
V_icmp_rates[i].cr.cr_ticks = ticks;
|
|
}
|
|
}
|
|
VNET_SYSINIT(icmp_bandlimit, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY,
|
|
icmp_bandlimit_init, NULL);
|
|
|
|
static void
|
|
icmp_bandlimit_uninit(void)
|
|
{
|
|
|
|
for (int i = 0; i < BANDLIM_MAX; i++)
|
|
counter_u64_free(V_icmp_rates[i].cr.cr_rate);
|
|
}
|
|
VNET_SYSUNINIT(icmp_bandlimit, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD,
|
|
icmp_bandlimit_uninit, NULL);
|
|
|
|
int
|
|
badport_bandlim(int which)
|
|
{
|
|
int64_t pps;
|
|
|
|
if (V_icmplim == 0 || which == BANDLIM_UNLIMITED)
|
|
return (0);
|
|
|
|
KASSERT(which >= 0 && which < BANDLIM_MAX,
|
|
("%s: which %d", __func__, which));
|
|
|
|
if ((V_icmplim + V_icmplim_curr_jitter) <= 0)
|
|
V_icmplim_curr_jitter = -V_icmplim + 1;
|
|
|
|
pps = counter_ratecheck(&V_icmp_rates[which].cr, V_icmplim +
|
|
V_icmplim_curr_jitter);
|
|
if (pps > 0) {
|
|
/*
|
|
* Adjust limit +/- to jitter the measurement to deny a
|
|
* side-channel port scan as in CVE-2020-25705
|
|
*/
|
|
if (V_icmplim_jitter > 0) {
|
|
int32_t inc =
|
|
arc4random_uniform(V_icmplim_jitter * 2 +1)
|
|
- V_icmplim_jitter;
|
|
|
|
V_icmplim_curr_jitter = inc;
|
|
}
|
|
}
|
|
if (pps == -1)
|
|
return (-1);
|
|
if (pps > 0 && V_icmplim_output)
|
|
log(LOG_NOTICE, "Limiting %s from %jd to %d packets/sec\n",
|
|
V_icmp_rates[which].descr, (intmax_t )pps, V_icmplim +
|
|
V_icmplim_curr_jitter);
|
|
return (0);
|
|
}
|