decode_http.c

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/*
 * decode_http.c
 *
 * Hypertext Transfer Protocol.
 *
 * Copyright (c) 2000 Dug Song <dugsong@monkey.org>
 *
 * $Id: decode_http.c,v 1.17 2001/03/15 08:32:59 dugsong Exp $
 */
 
#include "config.h"
 
#include <sys/types.h>
 
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <regex.h>
#include <libgen.h>
#include <err.h>
 
#include "base64.h"
#include "buf.h"
#include "decode.h"
 
#define USER_REGEX  ".*account.*|.*acct.*|.*domain.*|.*login.*|" \
            ".*member.*|.*user.*|.*name|.*email|.*_id|" \
            "id|uid|mn|mailaddress"
            
#define PASS_REGEX  ".*pass.*|.*pw|pw.*|additional_info"
 
#define REGEX_FLAGS (REG_EXTENDED | REG_ICASE | REG_NOSUB)
 
static regex_t      *user_regex, *pass_regex;
 
static int
grep_query_auth(char *buf)
{
    char *p, *q, *tmp;
    int user, pass;
 
    user = pass = 0;
    
    if ((tmp = strdup(buf)) == NULL)
        return (0);
    
    for (p = strtok(tmp, "&"); p != NULL; p = strtok(NULL, "&")) {
        if ((q = strchr(p, '=')) == NULL)
            continue;
        *q = '\0';
            
        if (!user) {
            if (regexec(user_regex, p, 0, NULL, 0) == 0) {
                user = 1;
                continue;
            }
        }
        if (!pass) {
            if (regexec(pass_regex, p, 0, NULL, 0) == 0)
                pass = 1;
        }
        if (user && pass) break;
    }
    free(tmp);
    
    return (user && pass);
}
 
static char *
http_req_dirname(char *req)
{
    char *uri, *vers;
    
    if ((uri = strchr(req, ' ')) == NULL)
        return (req);
    
    if ((vers = strrchr(uri, ' ')) == uri) {
        vers = NULL;
    }
    else if (vers[-1] == '/') {
        return (req);
    }
    else *vers++ = '\0';
    
    strcpy(req, dirname(req));
    strcat(req, "/");
    
    if (vers) {
        strcat(req, " ");
        strcat(req, vers);
    }
    return (req);
}  
 
int
decode_http(u_char *buf, int len, u_char *obuf, int olen)
{
    struct buf *msg, inbuf, outbuf;
    char *p, *req, *auth, *pauth, *query, *host;
    int i;
 
    buf_init(&inbuf, buf, len);
    buf_init(&outbuf, obuf, olen);
 
    if (user_regex == NULL || pass_regex == NULL) {
        if ((user_regex = malloc(sizeof(*user_regex))) == NULL ||
            (pass_regex = malloc(sizeof(*pass_regex))) == NULL)
            err(1, "malloc");
        
        if (regcomp(user_regex, USER_REGEX, REGEX_FLAGS) ||
            regcomp(pass_regex, PASS_REGEX, REGEX_FLAGS))
            errx(1, "regcomp failed");
    }
    while ((i = buf_index(&inbuf, "\r\n\r\n", 4)) >= 0) {
        msg = buf_tok(&inbuf, NULL, i);
        msg->base[msg->end] = '\0';
        buf_skip(&inbuf, 4);
 
        if ((req = strtok(buf_ptr(msg), "\r\n")) == NULL)
            continue;
 
        if (strncmp(req, "GET ", 4) != 0 &&
            strncmp(req, "POST ", 5) != 0 &&
            strncmp(req, "CONNECT ", 8) != 0)
            continue;
 
        auth = pauth = query = host = NULL;
 
        if ((query = strchr(req, '?')) != NULL)
            query++;
        
        while ((p = strtok(NULL, "\r\n")) != NULL) {
            if (strncasecmp(p, "Authorization: Basic ", 21) == 0) {
                auth = p;
            }               
            else if (strncasecmp(p, "Proxy-authorization: "
                         "Basic ", 27) == 0) {
                pauth = p;
            }
            else if (strncasecmp(p, "Host: ", 6) == 0) {
                host = p;
            }
            else if (req[0] == 'P') {
                if (strncmp(p, "Content-type: ", 14) == 0) {
                    if (strncmp(p + 14, "application/"
                            "x-www-form-urlencoded",
                            33) != 0) {
                        query = NULL;
                    }
                }
                else if (strncmp(p, "Content-length: ", 16) == 0) {
                    p += 16;
                    i = atoi(p);
                    if ((msg = buf_tok(&inbuf, NULL, i)) == NULL)
                        continue;
                    msg->base[msg->end] = '\0';
                    query = buf_ptr(msg);
                }
            }
        }
        if (auth || pauth || (query && grep_query_auth(query))) {
            if (buf_tell(&outbuf) > 0)
                buf_putf(&outbuf, "\n");
            
            if (req[0] == 'G' && auth)
                req = http_req_dirname(req);
 
            buf_putf(&outbuf, "%s\n", req);
            
            if (host)
                buf_putf(&outbuf, "%s\n", host);
            
            if (pauth) {
                buf_putf(&outbuf, "%s", pauth);
                p = pauth + 27;
                i = base64_pton(p, p, strlen(p));
                p[i] = '\0';
                buf_putf(&outbuf, " [%s]\n", p);
            }
            if (auth) {
                buf_putf(&outbuf, "%s", auth);
                p = auth + 21;
                i = base64_pton(p, p, strlen(p));
                p[i] = '\0';
                buf_putf(&outbuf, " [%s]\n", p);
            }
            else if (req[0] == 'P' && query) {
                buf_putf(&outbuf,
                     "Content-type: application/"
                     "x-www-form-urlencoded\n"
                     "Content-length: %d\n%s\n",
                     strlen(query), query);
            }
        }
    }
    buf_end(&outbuf);
    
    return (buf_len(&outbuf));
}