crypto/openssh/dispatch.c

   1 /* $OpenBSD: dispatch.c,v 1.32 2019/01/19 21:33:13 djm Exp $ */
   2 /*
   3  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "includes.h"
  27
  28 #include <sys/types.h>
  29
  30 #include <signal.h>
  31 #include <stdarg.h>
  32
  33 #include "ssh2.h"
  34 #include "log.h"
  35 #include "dispatch.h"
  36 #include "packet.h"
  37 #include "compat.h"
  38 #include "ssherr.h"
  39
  40 int
  41 dispatch_protocol_error(int type, u_int32_t seq, struct ssh *ssh)
  42 {
  43         int r;
  44
  45         logit("dispatch_protocol_error: type %d seq %u", type, seq);
  46         if ((r = sshpkt_start(ssh, SSH2_MSG_UNIMPLEMENTED)) != 0 ||
  47             (r = sshpkt_put_u32(ssh, seq)) != 0 ||
  48             (r = sshpkt_send(ssh)) != 0 ||
  49             (r = ssh_packet_write_wait(ssh)) != 0)
  50                 sshpkt_fatal(ssh, r, "%s", __func__);
  51         return 0;
  52 }
  53
  54 int
  55 dispatch_protocol_ignore(int type, u_int32_t seq, struct ssh *ssh)
  56 {
  57         logit("dispatch_protocol_ignore: type %d seq %u", type, seq);
  58         return 0;
  59 }
  60
  61 void
  62 ssh_dispatch_init(struct ssh *ssh, dispatch_fn *dflt)
  63 {
  64         u_int i;
  65         for (i = 0; i < DISPATCH_MAX; i++)
  66                 ssh->dispatch[i] = dflt;
  67 }
  68
  69 void
  70 ssh_dispatch_range(struct ssh *ssh, u_int from, u_int to, dispatch_fn *fn)
  71 {
  72         u_int i;
  73
  74         for (i = from; i <= to; i++) {
  75                 if (i >= DISPATCH_MAX)
  76                         break;
  77                 ssh->dispatch[i] = fn;
  78         }
  79 }
  80
  81 void
  82 ssh_dispatch_set(struct ssh *ssh, int type, dispatch_fn *fn)
  83 {
  84         ssh->dispatch[type] = fn;
  85 }
  86
  87 int
  88 ssh_dispatch_run(struct ssh *ssh, int mode, volatile sig_atomic_t *done)
  89 {
  90         int r;
  91         u_char type;
  92         u_int32_t seqnr;
  93
  94         for (;;) {
  95                 if (mode == DISPATCH_BLOCK) {
  96                         r = ssh_packet_read_seqnr(ssh, &type, &seqnr);
  97                         if (r != 0)
  98                                 return r;
  99                 } else {
 100                         r = ssh_packet_read_poll_seqnr(ssh, &type, &seqnr);
 101                         if (r != 0)
 102                                 return r;
 103                         if (type == SSH_MSG_NONE)
 104                                 return 0;
 105                 }
 106                 if (type > 0 && type < DISPATCH_MAX &&
 107                     ssh->dispatch[type] != NULL) {
 108                         if (ssh->dispatch_skip_packets) {
 109                                 debug2("skipped packet (type %u)", type);
 110                                 ssh->dispatch_skip_packets--;
 111                                 continue;
 112                         }
 113                         r = (*ssh->dispatch[type])(type, seqnr, ssh);
 114                         if (r != 0)
 115                                 return r;
 116                 } else {
 117                         r = sshpkt_disconnect(ssh,
 118                             "protocol error: rcvd type %d", type);
 119                         if (r != 0)
 120                                 return r;
 121                         return SSH_ERR_DISCONNECTED;
 122                 }
 123                 if (done != NULL && *done)
 124                         return 0;
 125         }
 126 }
 127
 128 void
 129 ssh_dispatch_run_fatal(struct ssh *ssh, int mode, volatile sig_atomic_t *done)
 130 {
 131         int r;
 132
 133         if ((r = ssh_dispatch_run(ssh, mode, done)) != 0)
 134                 sshpkt_fatal(ssh, r, "%s", __func__);
 135 }