decode_cvs.c

一个网络工具包,可以嗅探email和http等数据包中的密码等信息.注意要先把libnet-1.0.2a.tar.gz和 libnids-1.16.tar.gz装上,不然会因为缺少库函数而无法编译和安

/*
  decode_cvs.c

  Concurrent Versions System.
  
  Copyright (c) 2000 Dug Song <[e-mail]>
 
  $Id: decode_cvs.c,v 1.5 2000/11/15 05:54:51 dugsong Exp $
*/

#include "config.h"

#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include "buf.h"
#include "decode.h"

/* stolen from CVS scramble.c */
static u_char cvs_shifts[] = {
	0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,
	16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
	114,120, 53, 79, 96,109, 72,108, 70, 64, 76, 67,116, 74, 68, 87,
	111, 52, 75,119, 49, 34, 82, 81, 95, 65,112, 86,118,110,122,105,
	41, 57, 83, 43, 46,102, 40, 89, 38,103, 45, 50, 42,123, 91, 35,
	125, 55, 54, 66,124,126, 59, 47, 92, 71,115, 78, 88,107,106, 56,
	36,121,117,104,101,100, 69, 73, 99, 63, 94, 93, 39, 37, 61, 48,
	58,113, 32, 90, 44, 98, 60, 51, 33, 97, 62, 77, 84, 80, 85,223,
	225,216,187,166,229,189,222,188,141,249,148,200,184,136,248,190,
	199,170,181,204,138,232,218,183,255,234,220,247,213,203,226,193,
	174,172,228,252,217,201,131,230,197,211,145,238,161,179,160,212,
	207,221,254,173,202,146,224,151,140,196,205,130,135,133,143,246,
	192,159,244,239,185,168,215,144,139,165,180,157,147,186,214,176,
	227,231,219,169,175,156,206,198,129,164,150,210,154,177,134,127,
	182,128,158,208,162,132,167,209,149,241,153,251,237,236,171,195,
	243,233,253,240,194,250,191,155,142,137,245,235,163,242,178,152
};

int
decode_cvs(u_char *buf, int len, u_char *obuf, int olen)
{
	struct buf *line, inbuf, outbuf;
	u_char *p;
	int i, n;

	buf_init(&inbuf, buf, len);
	buf_init(&outbuf, obuf, olen);

	if (buf_cmp(&inbuf, "BEGIN ", 6) != 0)
		return (0);

	for (n = 0; n < 5 && (i = buf_index(&inbuf, "\n", 1)) != -1; n++) {
		line = buf_tok(&inbuf, NULL, i + 1);
		line->base[line->end - 1] = '\0';

		p = buf_ptr(line);
		buf_putf(&outbuf, "%s", p);
		
		if (n == 3) {
			if (p[0] != 'A')
				return (0);

			for (i = 1; i < sizeof(cvs_shifts) - 1 && p[i]; i++)
				p[i] = cvs_shifts[p[i]];
			
			buf_putf(&outbuf, " [%s]", p + 1);
		}
		buf_put(&outbuf, "\n", 1);
	}
	buf_end(&outbuf);
	
	return (buf_len(&outbuf));
}