utils.cc

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/***************************************************************************
 * utils.cc -- Various miscellaneous utility functions which defy          *
 * categorization :)                                                       *
 *                                                                         *
 ***********************IMPORTANT NMAP LICENSE TERMS************************
 *                                                                         *
 * The Nmap Security Scanner is (C) 1996-2006 Insecure.Com LLC. Nmap is    *
 * also a registered trademark of Insecure.Com LLC.  This program is free  *
 * software; you may redistribute and/or modify it under the terms of the  *
 * GNU General Public License as published by the Free Software            *
 * Foundation; Version 2 with the clarifications and exceptions described  *
 * below.  This guarantees your right to use, modify, and redistribute     *
 * this software under certain conditions.  If you wish to embed Nmap      *
 * technology into proprietary software, we sell alternative licenses      *
 * (contact [e-mail]).  Dozens of software vendors already       *
 * license Nmap technology such as host discovery, port scanning, OS       *
 * detection, and version detection.                                       *
 *                                                                         *
 * Note that the GPL places important restrictions on "derived works", yet *
 * it does not provide a detailed definition of that term.  To avoid       *
 * misunderstandings, we consider an application to constitute a           *
 * "derivative work" for the purpose of this license if it does any of the *
 * following:                                                              *
 * o Integrates source code from Nmap                                      *
 * o Reads or includes Nmap copyrighted data files, such as                *
 *   nmap-os-fingerprints or nmap-service-probes.                          *
 * o Executes Nmap and parses the results (as opposed to typical shell or  *
 *   execution-menu apps, which simply display raw Nmap output and so are  *
 *   not derivative works.)                                                * 
 * o Integrates/includes/aggregates Nmap into a proprietary executable     *
 *   installer, such as those produced by InstallShield.                   *
 * o Links to a library or executes a program that does any of the above   *
 *                                                                         *
 * The term "Nmap" should be taken to also include any portions or derived *
 * works of Nmap.  This list is not exclusive, but is just meant to        *
 * clarify our interpretation of derived works with some common examples.  *
 * These restrictions only apply when you actually redistribute Nmap.  For *
 * example, nothing stops you from writing and selling a proprietary       *
 * front-end to Nmap.  Just distribute it by itself, and point people to   *
 * http://insecure.org/nmap/ to download Nmap.                             *
 *                                                                         *
 * We don't consider these to be added restrictions on top of the GPL, but *
 * just a clarification of how we interpret "derived works" as it applies  *
 * to our GPL-licensed Nmap product.  This is similar to the way Linus     *
 * Torvalds has announced his interpretation of how "derived works"        *
 * applies to Linux kernel modules.  Our interpretation refers only to     *
 * Nmap - we don't speak for any other GPL products.                       *
 *                                                                         *
 * If you have any questions about the GPL licensing restrictions on using *
 * Nmap in non-GPL works, we would be happy to help.  As mentioned above,  *
 * we also offer alternative license to integrate Nmap into proprietary    *
 * applications and appliances.  These contracts have been sold to dozens  *
 * of software vendors, and generally include a perpetual license as well  *
 * as providing for priority support and updates as well as helping to     *
 * fund the continued development of Nmap technology.  Please email        *
 * [e-mail] for further information.                             *
 *                                                                         *
 * As a special exception to the GPL terms, Insecure.Com LLC grants        *
 * permission to link the code of this program with any version of the     *
 * OpenSSL library which is distributed under a license identical to that  *
 * listed in the included Copying.OpenSSL file, and distribute linked      *
 * combinations including the two. You must obey the GNU GPL in all        *
 * respects for all of the code used other than OpenSSL.  If you modify    *
 * this file, you may extend this exception to your version of the file,   *
 * but you are not obligated to do so.                                     *
 *                                                                         *
 * If you received these files with a written license agreement or         *
 * contract stating terms other than the terms above, then that            *
 * alternative license agreement takes precedence over these comments.     *
 *                                                                         *
 * Source is provided to this software because we believe users have a     *
 * right to know exactly what a program is going to do before they run it. *
 * This also allows you to audit the software for security holes (none     *
 * have been found so far).                                                *
 *                                                                         *
 * Source code also allows you to port Nmap to new platforms, fix bugs,    *
 * and add new features.  You are highly encouraged to send your changes   *
 * to [e-mail] for possible incorporation into the main         *
 * distribution.  By sending these changes to Fyodor or one the            *
 * Insecure.Org development mailing lists, it is assumed that you are      *
 * offering Fyodor and Insecure.Com LLC the unlimited, non-exclusive right *
 * to reuse, modify, and relicense the code.  Nmap will always be          *
 * available Open Source, but this is important because the inability to   *
 * relicense code has caused devastating problems for other Free Software  *
 * projects (such as KDE and NASM).  We also occasionally relicense the    *
 * code to third parties as discussed above.  If you wish to specify       *
 * special license conditions of your contributions, just say so when you  *
 * send them.                                                              *
 *                                                                         *
 * This program is distributed in the hope that it will be useful, but     *
 * WITHOUT ANY WARRANTY; without even the implied warranty of              *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU       *
 * General Public License for more details at                              *
 * http://www.gnu.org/copyleft/gpl.html , or in the COPYING file included  *
 * with Nmap.                                                              *
 *                                                                         *
 ***************************************************************************/

/* $Id: utils.cc 4204 2006-11-20 03:48:57Z fyodor $ */

#include "nmap.h"
#include "utils.h"
#include "NmapOps.h"

extern NmapOps o;

/* Hex dump */
void hdump(unsigned char *packet, unsigned int len) {
unsigned int i=0, j=0;

printf("Here it is:\n");

for(i=0; i < len; i++){
  j = (unsigned) (packet[i]);
  printf("%-2X ", j);
  if (!((i+1)%16))
    printf("\n");
  else if (!((i+1)%4))
    printf("  ");
}
printf("\n");
}

/* A better version of hdump, from Lamont Granquist.  Modified slightly
   by Fyodor ([e-mail]) */
void lamont_hdump(char *cp, unsigned int length) {

  /* stolen from tcpdump, then kludged extensively */

  static const char asciify[] = "................................ !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~.................................................................................................................................";

  const u_short *sp;
  const u_char *ap;
  unsigned char *bp = (unsigned char *) cp;
  u_int i, j;
  int nshorts, nshorts2;
  int padding;
  
  printf("\n\t");
  padding = 0;
  sp = (u_short *)bp;
  ap = (u_char *)bp;
  nshorts = (u_int) length / sizeof(u_short);
  nshorts2 = (u_int) length / sizeof(u_short);
  i = 0;
  j = 0;
  while(1) {
    while (--nshorts >= 0) {
      printf(" %04x", ntohs(*sp));
      sp++;
      if ((++i % 8) == 0)
        break;
    }
    if (nshorts < 0) {
      if ((length & 1) && (((i-1) % 8) != 0)) {
        printf(" %02x  ", *(u_char *)sp);
        padding++;
      }
      nshorts = (8 - (nshorts2 - nshorts));
      while(--nshorts >= 0) {
        printf("     ");
      }
      if (!padding) printf("     ");
    }
    printf("  ");

    while (--nshorts2 >= 0) {
      printf("%c%c", asciify[*ap], asciify[*(ap+1)]);
      ap += 2;
      if ((++j % 8) == 0) {
        printf("\n\t");
        break;
      }
    }
    if (nshorts2 < 0) {
      if ((length & 1) && (((j-1) % 8) != 0)) {
        printf("%c", asciify[*ap]);
      }
      break;
    }
  }
  if ((length & 1) && (((i-1) % 8) == 0)) {
    printf(" %02x", *(u_char *)sp);
    printf("                                       %c", asciify[*ap]);
  }
  printf("\n");
}

#ifndef HAVE_STRERROR
char *strerror(int errnum) {
  static char buf[1024];
  sprintf(buf, "your system is too old for strerror of errno %d\n", errnum);
  return buf;
}
#endif

/* Like the perl equivalent -- It removes the terminating newline from string
   IF one exists.  It then returns the POSSIBLY MODIFIED string */
char *chomp(char *string) {
  int len = strlen(string);
  if (len && string[len - 1] == '\n') {
    if (len > 1 && string[len - 2] == '\r')
      string[len - 2] = '\0';
    else
      string[len - 1] = '\0';
  }
  return string;
}

/* Compare a canonical option name (e.g. "max-scan-delay") with a
   user-generated option such as "max_scan_delay" and returns 0 if the
   two values are considered equivalant (for example, - and _ are
   considered to be the same), nonzero otherwise. */
int optcmp(const char *a, const char *b) {
  while(*a && *b) {
    if (*a == '_' || *a == '-') {
      if (*b != '_' && *b != '-')
	return 1;
    }
    else if (*a != *b)
      return 1;
    a++; b++;
  }
  if (*a || *b)
    return 1;
  return 0;
}

/* Convert a comma-separated list of ASCII u16-sized numbers into the
   given 'dest' array, which is of total size (meaning sizeof() as
   opposed to numelements) of destsize.  If min_elem and max_elem are
   provided, each number must be within (or equal to) those
   constraints.  The number of numbers stored in 'dest' is returned,
   except that -1 is returned in the case of an error. If -1 is
   returned and errorstr is non-null, *errorstr is filled with a ptr to a
   static string literal describing the error. */

int numberlist2array(char *expr, u16 *dest, int destsize, char **errorstr, u16 min_elem, u16 max_elem) {
  char *current_range;
  char *endptr;
  char *errbogus;
  long val;
  int max_vals = destsize / 2;
  int num_vals_saved = 0;
  current_range = expr;

  if (!errorstr)
    errorstr = &errbogus;

  if (destsize % 2 != 0) {
    *errorstr = "Bogus call to numerlist2array() -- destsize must be a multiple of 2";
    return -1;
  }

  if (!expr || !*expr)
    return 0;

  do {
    if (num_vals_saved == max_vals) {
      *errorstr = "Buffer would overflow -- too many numbers in provided list";
      return -1;
    }
    if( !isdigit((int) *current_range) ) {
      *errorstr = "Alleged number begins with nondigit!  Example of proper form: \"20,80,65532\"";
      return -1;
    }
    val = strtol(current_range, &endptr, 10);
    if( val < min_elem || val > max_elem ) {
      *errorstr = "Number given in list is outside given legal range";
      return -1;
    }
    dest[num_vals_saved++] = (u16) val;
    current_range = endptr;
    while (*current_range == ',' || isspace(*current_range))
      current_range++;
    if (*current_range && !isdigit(*current_range)) {
      *errorstr = "Bogus character in supposed number-list string. Example of proper form: \"20,80,65532\"";
      return -1;
    }
  } while( current_range && *current_range);

  return num_vals_saved;
}

/* Scramble the contents of an array*/
void genfry(unsigned char *arr, int elem_sz, int num_elem) {
int i;
unsigned int pos;
unsigned char *bytes;
unsigned char *cptr;
unsigned short *sptr;
unsigned int *iptr;
unsigned char *tmp;
int bpe;

if (sizeof(unsigned char) != 1)
  fatal("genfry() requires 1 byte chars");

if (num_elem < 2)
  return;

 if (elem_sz == sizeof(unsigned short)) {
   shortfry((unsigned short *)arr, num_elem);
   return;
 }

/* OK, so I am stingy with the random bytes! */
if (num_elem < 256) 
  bpe = sizeof(unsigned char);
else if (num_elem < 65536)
  bpe = sizeof(unsigned short);
else bpe = sizeof(unsigned int);

bytes = (unsigned char *) malloc(bpe * num_elem);
tmp = (unsigned char *) malloc(elem_sz);

get_random_bytes(bytes, bpe * num_elem);
cptr = bytes;
sptr = (unsigned short *)bytes;
iptr = (unsigned int *) bytes;

 for(i=num_elem - 1; i > 0; i--) {
   if (num_elem < 256) {
     pos = *cptr; cptr++;
   }
   else if (num_elem < 65536) {
     pos = *sptr; sptr++;
   } else {
     pos = *iptr; iptr++;
   }
   pos %= i+1;
   memcpy(tmp, arr + elem_sz * i, elem_sz);
   memcpy(arr + elem_sz * i, arr + elem_sz * pos, elem_sz);
   memcpy(arr + elem_sz * pos, tmp, elem_sz);
 }
 free(bytes);
 free(tmp);
}

void shortfry(unsigned short *arr, int num_elem) {
int num;
unsigned short tmp;
int i;

if (num_elem < 2)
  return;