samba-mirror/lib/util/rfc1738.c

/*
 * NOTE:  
 *
 * This file imported from the Squid project.  The licence below is
 * reproduced intact, but refers to files in Squid's repository, not
 * in Samba.  See COPYING for the GPLv3 notice (being the later
 * version mentioned below).
 *
 * This file has also been modified, in particular to use talloc to
 * allocate in rfc1738_escape()
 *
 * - Andrew Bartlett Oct-2009
 *
 */


/*
 * $Id$
 *
 * DEBUG:
 * AUTHOR: Harvest Derived
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; see the CREDITS file for full details.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include "replace.h"
#include <talloc.h>
#include "lib/util/samba_util.h"
#include "lib/util/util_str_hex.h"

/*
 *  RFC 1738 defines that these characters should be escaped, as well
 *  any non-US-ASCII character or anything between 0x00 - 0x1F.
 */
static char rfc1738_unsafe_chars[] = {
    (char) 0x3C,		/* < */
    (char) 0x3E,		/* > */
    (char) 0x22,		/* " */
    (char) 0x23,		/* # */
#if 0				/* done in code */
    (char) 0x25,		/* % */
#endif
    (char) 0x7B,		/* { */
    (char) 0x7D,		/* } */
    (char) 0x7C,		/* | */
    (char) 0x5C,		/* \ */
    (char) 0x5E,		/* ^ */
    (char) 0x7E,		/* ~ */
    (char) 0x5B,		/* [ */
    (char) 0x5D,		/* ] */
    (char) 0x60,		/* ` */
    (char) 0x27,		/* ' */
    (char) 0x20			/* space */
};

static char rfc1738_reserved_chars[] = {
    (char) 0x3b,		/* ; */
    (char) 0x2f,		/* / */
    (char) 0x3f,		/* ? */
    (char) 0x3a,		/* : */
    (char) 0x40,		/* @ */
    (char) 0x3d,		/* = */
    (char) 0x26			/* & */
};

/*
 *  rfc1738_escape - Returns a static buffer contains the RFC 1738
 *  compliant, escaped version of the given url.
 *
 */
static char *
rfc1738_do_escape(TALLOC_CTX *mem_ctx, const char *url, int encode_reserved)
{
    size_t bufsize = 0;
    const char *p;
    char *buf;
    char *q;
    unsigned int i, do_escape;

    bufsize = strlen(url) * 3 + 1;
    buf = talloc_array(mem_ctx, char, bufsize);
    if (!buf) {
	    return NULL;
    }

    talloc_set_name_const(buf, buf);
    buf[0] = '\0';

    for (p = url, q = buf; *p != '\0' && q < (buf + bufsize - 1); p++, q++) {
        do_escape = 0;

        /* RFC 1738 defines these chars as unsafe */
        for (i = 0; i < sizeof(rfc1738_unsafe_chars); i++) {
            if (*p == rfc1738_unsafe_chars[i]) {
                do_escape = 1;
                break;
            }
        }
        /* Handle % separately */
        if (encode_reserved >= 0 && *p == '%')
            do_escape = 1;
        /* RFC 1738 defines these chars as reserved */
        for (i = 0; i < sizeof(rfc1738_reserved_chars) && encode_reserved > 0; i++) {
            if (*p == rfc1738_reserved_chars[i]) {
                do_escape = 1;
                break;
            }
        }
        /* RFC 1738 says any control chars (0x00-0x1F) are encoded */
        if ((unsigned char) *p <= (unsigned char) 0x1F) {
            do_escape = 1;
        }
        /* RFC 1738 says 0x7f is encoded */
        if (*p == (char) 0x7F) {
            do_escape = 1;
        }
        /* RFC 1738 says any non-US-ASCII are encoded */
        if (((unsigned char) *p >= (unsigned char) 0x80)) {
            do_escape = 1;
        }
        /* Do the triplet encoding, or just copy the char */
        /* note: while we do not need snprintf here as q is appropriately
         * allocated, Samba does to avoid our macro banning it -- abartlet */

        if (do_escape == 1) {
		(void) snprintf(q, 4, "%%%02X", (unsigned char) *p);
            q += sizeof(char) * 2;
        } else {
            *q = *p;
        }
    }
    *q = '\0';
    return (buf);
}

/*
 * rfc1738_escape_part - Returns a buffer that contains the RFC
 * 1738 compliant, escaped version of the given url segment. (escapes
 * unsafe, reserved and % chars) It would mangle the :// in http://,
 * and mangle paths (because of /).
 */
char *
rfc1738_escape_part(TALLOC_CTX *mem_ctx, const char *url)
{
	return rfc1738_do_escape(mem_ctx, url, 1);
}

/*
 * rfc1738_unescape() - Converts url-escaped characters in the string.
 *
 * The two characters following a '%' in a string should be hex digits that
 * describe an encoded byte. For example, "%25" is hex 0x25 or '%' in ASCII;
 * this is the only way to include a % in the unescaped string. Any character
 * can be escaped, including plain letters (e.g. "%61" for "a"). Anything
 * other than 2 hex characters following the % is an error.
 *
 * The conversion is done in-place, which is always safe as unescapes can only
 * shorten the string.
 *
 * Returns a pointer to the end of the string (that is, the '\0' byte), or
 * NULL on error, at which point s is in an undefined state.
 *
 * Note that after `char *e = rfc_unescape(s)`, `strlen(s)` will not equal
 * `e - s` if s originally contained "%00". You might want to check for this.
 */

_PUBLIC_ char *rfc1738_unescape(char *s)
{
	size_t i, j;	    /* i is write, j is read */
	uint64_t x;
	NTSTATUS status;
	for (i = 0, j = 0; s[j] != '\0'; i++, j++) {
		if (s[j] == '%') {
			status = read_hex_bytes(&s[j + 1], 2, &x);
			if (! NT_STATUS_IS_OK(status)) {
				return NULL;
			}
			j += 2; /* OK; read_hex_bytes() has checked ahead */
			s[i] = (unsigned char)x;
		} else {
			s[i] = s[j];
		}
	}
	s[i] = '\0';
	return s + i;
}