proxy_ftp.c

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/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* FTP routines for Apache proxy */

#include "mod_proxy.h"
#include "http_main.h"
#include "http_log.h"
#include "http_core.h"

#define AUTODETECT_PWD

/*
 * Decodes a '%' escaped string, and returns the number of characters
 */
static int decodeenc(char *x)
{
    int i, j, ch;

    if (x[0] == '\0')
        return 0;               /* special case for no characters */
    for (i = 0, j = 0; x[i] != '\0'; i++, j++) {
/* decode it if not already done */
        ch = x[i];
        if (ch == '%' && ap_isxdigit(x[i + 1]) && ap_isxdigit(x[i + 2])) {
            ch = ap_proxy_hex2c(&x[i + 1]);
            i += 2;
        }
        x[j] = ch;
    }
    x[j] = '\0';
    return j;
}

/*
 * checks an encoded ftp string for bad characters, namely, CR, LF or
 * non-ascii character
 */
static int ftp_check_string(const char *x)
{
    int i, ch;

    for (i = 0; x[i] != '\0'; i++) {
        ch = x[i];
        if (ch == '%' && ap_isxdigit(x[i + 1]) && ap_isxdigit(x[i + 2])) {
            ch = ap_proxy_hex2c(&x[i + 1]);
            i += 2;
        }
        if (ch == CR || ch == LF || (OS_ASC(ch) & 0x80))
            return 0;
    }
    return 1;
}

/*
 * Canonicalise ftp URLs.
 */
int ap_proxy_ftp_canon(request_rec *r, char *url)
{
    char *user, *password, *host, *path, *parms, *strp, sport[7];
    pool *p = r->pool;
    const char *err;
    int port;

    port = DEFAULT_FTP_PORT;
    err = ap_proxy_canon_netloc(p, &url, &user, &password, &host, &port);
    if (err)
        return HTTP_BAD_REQUEST;
    if (user != NULL && !ftp_check_string(user))
        return HTTP_BAD_REQUEST;
    if (password != NULL && !ftp_check_string(password))
        return HTTP_BAD_REQUEST;

/* now parse path/parameters args, according to rfc1738 */
/* N.B. if this isn't a true proxy request, then the URL path
 * (but not query args) has already been decoded.
 * This gives rise to the problem of a ; being decoded into the
 * path.
 */
    strp = strchr(url, ';');
    if (strp != NULL) {
        *(strp++) = '\0';
        parms = ap_proxy_canonenc(p, strp, strlen(strp), enc_parm,
                                  r->proxyreq);
        if (parms == NULL)
            return HTTP_BAD_REQUEST;
    }
    else
        parms = "";

    path = ap_proxy_canonenc(p, url, strlen(url), enc_path, r->proxyreq);
    if (path == NULL)
        return HTTP_BAD_REQUEST;
    if (!ftp_check_string(path))
        return HTTP_BAD_REQUEST;

    if (r->proxyreq == NOT_PROXY && r->args != NULL) {
        if (strp != NULL) {
            strp = ap_proxy_canonenc(p, r->args, strlen(r->args), enc_parm, STD_PROXY);
            if (strp == NULL)
                return HTTP_BAD_REQUEST;
            parms = ap_pstrcat(p, parms, "?", strp, NULL);
        }
        else {
            strp = ap_proxy_canonenc(p, r->args, strlen(r->args), enc_fpath, STD_PROXY);
            if (strp == NULL)
                return HTTP_BAD_REQUEST;
            path = ap_pstrcat(p, path, "?", strp, NULL);
        }
        r->args = NULL;
    }

/* now, rebuild URL */

    if (port != DEFAULT_FTP_PORT)
        ap_snprintf(sport, sizeof(sport), ":%d", port);
    else
        sport[0] = '\0';

    r->filename = ap_pstrcat(p, "proxy:ftp://", (user != NULL) ? user : "",
                             (password != NULL) ? ":" : "",
                             (password != NULL) ? password : "",
                          (user != NULL) ? "@" : "", host, sport, "/", path,
                             (parms[0] != '\0') ? ";" : "", parms, NULL);

    return OK;
}

/*
 * Returns the ftp status code;
 *  or -1 on I/O error, 0 on data error
 */
static int ftp_getrc(BUFF *ctrl)
{
    int len, status;
    char linebuff[100], buff[5];

    len = ap_bgets(linebuff, sizeof linebuff, ctrl);
    if (len == -1)
        return -1;
/* check format */
    if (len < 5 || !ap_isdigit(linebuff[0]) || !ap_isdigit(linebuff[1]) ||
     !ap_isdigit(linebuff[2]) || (linebuff[3] != ' ' && linebuff[3] != '-'))
        status = 0;
    else
        status = 100 * linebuff[0] + 10 * linebuff[1] + linebuff[2] - 111 * '0';

    if (linebuff[len - 1] != '\n') {
        (void)ap_bskiplf(ctrl);
    }

/* skip continuation lines */
    if (linebuff[3] == '-') {
        memcpy(buff, linebuff, 3);
        buff[3] = ' ';
        do {
            len = ap_bgets(linebuff, sizeof linebuff, ctrl);
            if (len == -1)
                return -1;
            if (linebuff[len - 1] != '\n') {
                (void)ap_bskiplf(ctrl);
            }
        } while (memcmp(linebuff, buff, 4) != 0);
    }

    return status;
}

/*
 * Like ftp_getrc but returns both the ftp status code and
 * remembers the response message in the supplied buffer
 */
static int ftp_getrc_msg(BUFF *ctrl, char *msgbuf, int msglen)
{
    int len, status;
    char linebuff[100], buff[5];
    char *mb = msgbuf, *me = &msgbuf[msglen];

    len = ap_bgets(linebuff, sizeof linebuff, ctrl);
    if (len == -1)
        return -1;
    if (len < 5 || !ap_isdigit(linebuff[0]) || !ap_isdigit(linebuff[1]) ||
     !ap_isdigit(linebuff[2]) || (linebuff[3] != ' ' && linebuff[3] != '-'))
        status = 0;
    else
        status = 100 * linebuff[0] + 10 * linebuff[1] + linebuff[2] - 111 * '0';

    mb = ap_cpystrn(mb, linebuff + 4, me - mb);

    if (linebuff[len - 1] != '\n')
        (void)ap_bskiplf(ctrl);

    if (linebuff[3] == '-') {
        memcpy(buff, linebuff, 3);
        buff[3] = ' ';
        do {
            len = ap_bgets(linebuff, sizeof linebuff, ctrl);
            if (len == -1)
                return -1;
            if (linebuff[len - 1] != '\n') {
                (void)ap_bskiplf(ctrl);
            }
            mb = ap_cpystrn(mb, linebuff + 4, me - mb);
        } while (memcmp(linebuff, buff, 4) != 0);
    }
    return status;
}

static long int send_dir(BUFF *data, request_rec *r, cache_req *c, char *cwd)
{
    char *buf, *buf2;
    size_t buf_size;
    char *filename;
    int searchidx = 0;
    char *searchptr = NULL;
    int firstfile = 1;
    unsigned long total_bytes_sent = 0;
    register int n;
    conn_rec *con = r->connection;
    pool *p = r->pool;
    char *dir, *path, *reldir, *site, *type = NULL;
    char *basedir = "";         /* By default, path is relative to the $HOME
                                 * dir */

    /* create default sized buffers for the stuff below */
    buf_size = IOBUFSIZE;
    buf = ap_palloc(r->pool, buf_size);
    buf2 = ap_palloc(r->pool, buf_size);

    /* Save "scheme://site" prefix without password */
    site = ap_unparse_uri_components(p, &r->parsed_uri, UNP_OMITPASSWORD | UNP_OMITPATHINFO);
    /* ... and path without query args */
    path = ap_unparse_uri_components(p, &r->parsed_uri, UNP_OMITSITEPART | UNP_OMITQUERY);

    /* If path began with /%2f, change the basedir */
    if (strncasecmp(path, "/%2f", 4) == 0) {
        basedir = "/%2f";
    }

    /* Strip off a type qualifier. It is ignored for dir listings */
    if ((type = strstr(path, ";type=")) != NULL)
        *type++ = '\0';

    (void)decodeenc(path);

    while (path[1] == '/')      /* collapse multiple leading slashes to one */
        ++path;

    /* Copy path, strip (all except the last) trailing slashes */
    /* (the trailing slash is needed for the dir component loop below) */
    path = dir = ap_pstrcat(r->pool, path, "/", NULL);
    for (n = strlen(path); n > 1 && path[n - 1] == '/' && path[n - 2] == '/'; --n)
        path[n - 1] = '\0';

    /* print "ftp://host/" */
    n = ap_snprintf(buf, buf_size, DOCTYPE_HTML_3_2
                    "<html><head><title>%s%s%s</title>\n"
                    "<base href=\"%s%s%s\"></head>\n"
                    "<body><h2>Directory of "
                    "<a href=\"/\">%s</a>/",
                    site, basedir, ap_escape_html(p, path),
                    site, basedir, ap_escape_uri(p, path),
                    site);
    total_bytes_sent += ap_proxy_bputs2(buf, con->client, c);

    /* Add a link to the root directory (if %2f hack was used) */
    if (basedir[0] != '\0') {
        total_bytes_sent += ap_proxy_bputs2("<a href=\"/%2f/\">%2f</a>/", con->client, c);
    }

    for (dir = path + 1; (dir = strchr(dir, '/')) != NULL;) {
        *dir = '\0';
        if ((reldir = strrchr(path + 1, '/')) == NULL) {
            reldir = path + 1;
        }
        else
            ++reldir;
        /* print "path/" component */
        ap_snprintf(buf, buf_size, "<a href=\"%s%s/\">%s</a>/",
                    basedir,
                    ap_escape_uri(p, path),
                    ap_escape_html(p, reldir));
        total_bytes_sent += ap_proxy_bputs2(buf, con->client, c);
        *dir = '/';
        while (*dir == '/')
            ++dir;
    }

    /* If the caller has determined the current directory, and it differs */
    /* from what the client requested, then show the real name */
    if (cwd == NULL || strncmp(cwd, path, strlen(cwd)) == 0) {
        ap_snprintf(buf, buf_size, "</h2>\n<hr /><pre>");
    }
    else {
        ap_snprintf(buf, buf_size, "</h2>\n(%s)\n<hr /><pre>",
                    ap_escape_html(p, cwd));
    }
    total_bytes_sent += ap_proxy_bputs2(buf, con->client, c);

    while (!con->aborted) {
        n = ap_bgets(buf, buf_size, data);
        if (n == -1) {          /* input error */
            if (c != NULL) {
                ap_log_rerror(APLOG_MARK, APLOG_ERR, c->req,
                              "proxy: error reading from %s", c->url);
                c = ap_proxy_cache_error(c);
            }
            break;
        }
        if (n == 0)
            break;              /* EOF */

        if (buf[n - 1] == '\n') /* strip trailing '\n' */
            buf[--n] = '\0';
        if (buf[n - 1] == '\r') /* strip trailing '\r' if present */
            buf[--n] = '\0';

        /* Handle unix-style symbolic link */
        if (buf[0] == 'l' && (filename = strstr(buf, " -> ")) != NULL) {
            char *link_ptr = filename;

            do {
                filename--;
            } while (filename[0] != ' ' && filename > buf);
            if (filename != buf)
                *(filename++) = '\0';
            *(link_ptr++) = '\0';
            ap_snprintf(buf2, buf_size, "%s <a href=\"%s\">%s %s</a>\n",
                        ap_escape_html(p, buf),
                        ap_escape_uri(p, filename),
                        ap_escape_html(p, filename),
                        ap_escape_html(p, link_ptr));
            ap_cpystrn(buf, buf2, buf_size);
            n = strlen(buf);
        }
        /* Handle unix style or DOS style directory  */