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Diffstat (limited to 'lib/util/rfc1738.c')
| -rw-r--r-- | lib/util/rfc1738.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/lib/util/rfc1738.c b/lib/util/rfc1738.c new file mode 100644 index 0000000..7b8db11 --- /dev/null +++ b/lib/util/rfc1738.c @@ -0,0 +1,198 @@ +/* + * Functions for RFC 3986 percent-encoding. + * + * NOTE: + * + * This file was originally imported from the Squid project but has been + * significantly altered. 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). + */ + +/* + * $Id$ + * + * 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" + +#define RFC1738_ENCODE 1 +#define RFC1738_RESERVED 2 + +/* + * According to RFC 1738, "$-_.+!*'()," are not reserved or unsafe, but as + * that has been obsolete since 2004, we sm instead for RFC 3986, where: + * + * reserved = : / ? # [ ] @ ! $ & ' ( ) * + , ; = + * unreserved = ALPHA DIGIT - . _ ~ + * + * and whatever is not in either of those are what RFC 1738 called "unsafe", + * meaning that they should are canonically but not mandatorily escaped. + * + * Characters below 0x20 or above 0x7E are always encoded. + */ + +static const unsigned char escapees[127] = { + [' '] = RFC1738_ENCODE, + ['"'] = RFC1738_ENCODE, + ['%'] = RFC1738_ENCODE, + ['<'] = RFC1738_ENCODE, + ['>'] = RFC1738_ENCODE, + ['\\'] = RFC1738_ENCODE, + ['^'] = RFC1738_ENCODE, + ['`'] = RFC1738_ENCODE, + ['{'] = RFC1738_ENCODE, + ['|'] = RFC1738_ENCODE, + ['}'] = RFC1738_ENCODE, + /* reserved : / ? # [ ] @ ! $ & ' ( ) * + , ; = */ + [':'] = RFC1738_RESERVED, + ['/'] = RFC1738_RESERVED, + ['?'] = RFC1738_RESERVED, + ['#'] = RFC1738_RESERVED, + ['['] = RFC1738_RESERVED, + [']'] = RFC1738_RESERVED, + ['@'] = RFC1738_RESERVED, + ['!'] = RFC1738_RESERVED, + ['$'] = RFC1738_RESERVED, + ['&'] = RFC1738_RESERVED, + ['\''] = RFC1738_RESERVED, + ['('] = RFC1738_RESERVED, + [')'] = RFC1738_RESERVED, + ['*'] = RFC1738_RESERVED, + ['+'] = RFC1738_RESERVED, + [','] = RFC1738_RESERVED, + [';'] = RFC1738_RESERVED, + ['='] = RFC1738_RESERVED, +}; + +/* + * rfc1738_do_escape - fills a preallocated buffer with an escaped version of + * the given string. + * + * For canonical escaping, mask should be RFC1738_ENCODE | RFC1738_RESERVED. + * For mandatory escaping, mask should be RFC1738_RESERVED. + */ +static char * +rfc1738_do_escape(char *buf, size_t bufsize, + const char *url, size_t len, unsigned char mask) +{ + size_t i; + size_t j = 0; + for (i = 0; i < len; i++) { + unsigned int c = (unsigned char) url[i]; + if (c > 126 || c < 32 || (escapees[c] & mask)) { + if (j + 3 >= bufsize) { + return NULL; + } + (void) snprintf(&buf[j], 4, "%%%02X", c); + j += 3; + } else { + if (j + 1 >= bufsize) { + return NULL; + } + buf[j] = c; + j++; + } + } + buf[j] = '\0'; + return buf; +} + +/* + * rfc1738_escape_part - Returns a talloced buffer that contains the RFC 3986 + * compliant, escaped version of the given url segment. + */ +char * +rfc1738_escape_part(TALLOC_CTX *mem_ctx, const char *url) +{ + size_t bufsize = 0; + char *buf = NULL; + + size_t len = strlen(url); + if (len >= SIZE_MAX / 3) { + return NULL; + } + + bufsize = len * 3 + 1; + buf = talloc_array(mem_ctx, char, bufsize); + if (buf == NULL) { + return NULL; + } + + talloc_set_name_const(buf, buf); + + return rfc1738_do_escape(buf, bufsize, url, len, + RFC1738_ENCODE | RFC1738_RESERVED); +} + +/* + * 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 */ + for (i = 0, j = 0; s[j] != '\0'; i++, j++) { + if (s[j] == '%') { + uint8_t v; + bool ok; + + ok = hex_byte(&s[j+1], &v); + if (!ok) { + return NULL; + } + j += 2; /* OK; hex_byte() has checked ahead */ + s[i] = (unsigned char)v; + } else { + s[i] = s[j]; + } + } + s[i] = '\0'; + return s + i; +} |