The Tcpdump Group git mirrors - tcpdump/blob - print-ssh.c

   1 /*
   2  * Redistribution and use in source and binary forms, with or without
   3  * modification, are permitted provided that: (1) source code
   4  * distributions retain the above copyright notice and this paragraph
   5  * in its entirety, and (2) distributions including binary code include
   6  * the above copyright notice and this paragraph in its entirety in
   7  * the documentation or other materials provided with the distribution.
   8  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
   9  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
  10  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  11  * FOR A PARTICULAR PURPOSE.
  12  */
  13
  14 /* \summary: Secure Shell (SSH) printer */
  15
  16 #ifdef HAVE_CONFIG_H
  17 #include <config.h>
  18 #endif
  19
  20 #include "netdissect-stdinc.h"
  21
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24
  25 #include "netdissect-ctype.h"
  26
  27 #include "netdissect.h"
  28 #include "extract.h"
  29
  30 static int
  31 ssh_print_version(netdissect_options *ndo, const u_char *pptr, u_int len)
  32 {
  33         u_int idx = 0;
  34
  35         if ( GET_U_1(pptr+idx) != 'S' )
  36                 return 0;
  37         idx++;
  38         if ( GET_U_1(pptr+idx) != 'S' )
  39                 return 0;
  40         idx++;
  41         if ( GET_U_1(pptr+idx) != 'H' )
  42                 return 0;
  43         idx++;
  44         if ( GET_U_1(pptr+idx) != '-' )
  45                 return 0;
  46         idx++;
  47
  48         while (idx < len) {
  49                 u_char c;
  50
  51                 c = GET_U_1(pptr + idx);
  52                 if (c == '\n') {
  53                         /*
  54                          * LF without CR; end of line.
  55                          * Skip the LF and print the line, with the
  56                          * exception of the LF.
  57                          */
  58                         goto print;
  59                 } else if (c == '\r') {
  60                         /* CR - any LF? */
  61                         if ((idx+1) >= len) {
  62                                 /* not in this packet */
  63                                 goto trunc;
  64                         }
  65                         if (GET_U_1(pptr + idx + 1) == '\n') {
  66                                 /*
  67                                  * CR-LF; end of line.
  68                                  * Skip the CR-LF and print the line, with
  69                                  * the exception of the CR-LF.
  70                                  */
  71                                 goto print;
  72                         }
  73
  74                         /*
  75                          * CR followed by something else; treat this as
  76                          * if it were binary data and don't print it.
  77                          */
  78                         goto trunc;
  79                 } else if (!ND_ASCII_ISPRINT(c) ) {
  80                         /*
  81                          * Not a printable ASCII character; treat this
  82                          * as if it were binary data and don't print it.
  83                          */
  84                         goto trunc;
  85                 }
  86                 idx++;
  87         }
  88 trunc:
  89         return -1;
  90 print:
  91         ND_PRINT(": ");
  92         nd_print_protocol_caps(ndo);
  93         ND_PRINT(": %.*s", (int)idx, pptr);
  94         return idx;
  95 }
  96
  97 void
  98 ssh_print(netdissect_options *ndo, const u_char *pptr, u_int len)
  99 {
 100         ndo->ndo_protocol = "ssh";
 101
 102         ssh_print_version(ndo, pptr, len);
 103 }