nmap/scripts/fingerlib.cc

/***************************************************************************
 * fingerlib.cc/.h -- Some misc. functions related to fingerprint parsing  *
 * and the like to be used by integration-related programs such as         *
 * fingerfix, fingermatch, and fingerdiff                                  *
 *                                                                         *
 ***********************IMPORTANT NMAP LICENSE TERMS************************
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 *                                                                         *
 ***************************************************************************/


#include "nbase.h"
#include "nmap.h"
#include "fingerlib.h"
#include "MACLookup.h"

static int checkFP(char *FP) {
  char *p;
  char macbuf[16];
  u8 macprefix[3];
  char tmp;
  bool founderr = false;
  int i;

  // SCAN
  p = strstr(FP, "SCAN(");
  if(!p) {
	founderr = true;
	printf("[WARN] SCAN line is missing");
  } else {
	// SCAN.G: whether the fingerprint is good
	p = strstr(FP, "%G=");
	if(!p) p = strstr(FP, "(G=");
	if(!p) {
	  printf("[WARN] Attribute G is missing in SCAN line\n");
	  founderr = true;
	} else {
	  tmp = *(p+3);
	  if(tmp != 'Y') {
		printf("[WARN] One fingerprint is not good\n");
		founderr = true;
	  }
	}
	
	// SCAN.M: mac prefix of the target.
	// if there is a MAC prefix, print the vendor name
	p = strstr(FP, "%M=");
	if(!p) p = strstr(FP, "(M=");
	if(p) {
	  p = p + 3;
	  for(i = 0; i < 6; i++) {
		if(!p[i] || !isxdigit(p[i])) {
		  printf("[WARN] Invalid value (%s) occurs in SCAN.M\n", p);
		  founderr = true;
		  break;
		}
	  }
	  if(!founderr) {
		strncpy(macbuf, p, 6);
		i = strtol(macbuf, NULL, 16);
		macprefix[0] = i >> 16;
		macprefix[1] = (i >> 8) & 0xFF;
		macprefix[2] = i & 0xFF;
		printf("[INFO] Vendor Info: %s\n", MACPrefix2Corp(macprefix));
	  }
	}
  }

  /* Now we validate that all elements are present */
  p = FP;
  if (!strstr(p, "SEQ(") || !strstr(p, "OPS(") || !strstr(p, "WIN(") || 
	  !strstr(p, "ECN(") || !strstr(p, "T1(") || !strstr(p, "T2(") || 
      !strstr(p, "T3(") || !strstr(p, "T4(") || !strstr(p, "T5(") || 
      !strstr(p, "T6(") || !strstr(p, "T7(") || !strstr(p, "U1(") ||
	  !strstr(p, "IE(")) {
    /* This ought to get my attention :) */
	founderr = true;
    printf("[WARN] Fingerprint is missing at least 1 element\n");
  }
  
  if(founderr) return -1;
  return 0;
}


/* Reads a fingerprint in from the filep file descriptor.  The FP may
   be in wrapped or unwrapped format.  Wrapped prints are unrapped
   before being returned in FP.  Returns -1 or exits if it fails. */
int readFP(FILE *filep, char *FP, int FPsz ) {
  char line[512];
  int linelen = 0;
  int lineno = 0;
  char *p, *q;
  char *oneFP;
  char *dst = FP;
  char tmp[16];
  int i;
  bool isInWrappedFP = false; // whether we are currently reading in a
							  // wrapped fingerprint
  
  if(FPsz < 50) return -1;
  FP[0] = '\0';

  while((fgets(line, sizeof(line), filep))) {
	lineno++;
	linelen = strlen(line);
	p = line;
	if (*p == '\n' || *p == '.') {
	  // end of input
	  *dst = '\0';	  

	  if(isInWrappedFP) {
	    // We have just completed reading in a wrapped fp. Because a
	    // wrapped fp is submitted by user, so we check if there is a
	    // SCAN line in it. If yes, look inside the scan line.
	    checkFP(oneFP);
	    isInWrappedFP = false;
	  }  
	  break;
	}
	while(*p && isspace(*p)) p++;
	if (*p == '#') 
	  continue; // skip the comment line

	if (dst - FP + linelen >= FPsz - 5)
	  fatal("[ERRO] Overflow!\n");
	
	if(strncmp(p, "OS:", 3) == 0) {
	  // the line is start with "OS:"
	  if(!isInWrappedFP) {
		// just enter a wrapped fp area
		oneFP = dst;
		isInWrappedFP = true;
	  }
	  p += 3;
	  while(*p != '\r' && *p != '\n') {
	    *dst++ = toupper(*p);
	    if(*p == ')') *dst++ = '\n';
	    p++;
	  }
	  continue;
	}

	// this line is not start with "OS:"
	if(isInWrappedFP) {
	  // We have just completed reading in a wrapped fp. Because a
	  // wrapped fp is submitted by user, so we check if there is a
	  // SCAN line in it. If yes, look inside the scan line.
	  *dst = '\0';
	  checkFP(oneFP);
	  isInWrappedFP = false;
	}

	q = p; i = 0;
	while(q && *q && i<12)
	  tmp[i++] = toupper(*q++);
	tmp[i] = '\0';
	if(strncmp(tmp, "FINGERPRINT", 11) == 0) {
	  q = p + 11;
	  while(*q && isspace(*q)) q++;
	  if (*q) { // this fingeprint line is not empty
		strncpy(dst, "Fingerprint", 11);
		dst += 11;
		p += 11;
		while(*p) *dst++ = *p++;
	  }
	  continue;
	} else if(strncmp(tmp, "CLASS", 5) == 0) {
	  q = p + 5;
	  while(*q && isspace(*q)) q++;
	  if (*q) {// this class line is not empty
		strncpy(dst, "Class", 5);
		dst += 5;
		p += 5;
		while(*p) *dst++ = *p++;
	  }
	  continue;
	} else if(strchr(p, '(')) {
	  while(*p) *dst++ = toupper(*p++);
	} else {
	  printf("[WARN] Skip bogus line: %s\n", p);
	  continue;
	}
  }

  // Now we validate that all elements are present. Though this maybe
  // redundant because we have checked it for those wrapped FPs, it
  // doesn't hurt to give a duplicated warning here.
  p = FP;
  if (!strstr(p, "SEQ(") || !strstr(p, "OPS(") || !strstr(p, "WIN(") || 
	  !strstr(p, "ECN(") || !strstr(p, "T1(") || !strstr(p, "T2(") || 
      !strstr(p, "T3(") || !strstr(p, "T4(") || !strstr(p, "T5(") || 
      !strstr(p, "T6(") || !strstr(p, "T7(") || !strstr(p, "U1(") ||
	  !strstr(p, "IE(")) {
    /* This ought to get my attention :) */
    printf("[WARN] Fingerprint is missing at least 1 element\n");
  }
  
  if (dst - FP < 1)
    return -1;
  return 0;
}

static int count_attributes(struct AVal *res) {
  int count = 0;
  while(res) {
    count++;
    res = res->next;
  }
  return count;
}

/* When Nmap prints a fingerprint for submission, it sometimes
   includes duplicates of tests because 1 or more elements of that
   test differ.  While this is important for things like fingerfix
   (submission), other scripts can't handle it.  So this function
   removes the duplicates.  Maybe it should have more smarts, but
   currently it just keeps the first instance of each test.  Returns
   the number of duplicate tests (0 if there were none). The function
   quits and prints the problem if there is an error. */
int remove_duplicate_tests(FingerPrint *FP) {
  FingerPrint *outer = FP, *inner, *tmp;
  int dupsfound = 0;
  if (!FP) { fatal("NULL FP passed to %s", __FUNCTION__); }

  for(outer = FP; outer; outer = outer->next) {
    /* We check if this test has any duplicates forward in the list,
       and if so, remove them */
    for(inner = outer; inner->next; inner = inner->next) {
      if (strcmp(outer->name, inner->next->name) == 0) {
	/* DUPLICATE FOUND!  REMOVE THE ONE W/THE FEWEST ATTRIBUTES */
	int outeratts = count_attributes(outer->results);
	int inneratts = count_attributes(inner->next->results);
	if (inneratts > outeratts) {
	  /* We do a swap of members because we can't change the address of 'FP' */
	  outer->results = inner->next->results; /* MEMORY LEAK BUT THATS OK */
	}
	dupsfound++;
	inner->next = inner->next->next; /* MEMORY LEAK, BUT THATS OK */
      }
      if (!inner->next) break;
    }
  }
  return dupsfound;
}