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/*
* Copyright (C) 2004-2005 Kay Sievers <kay.sievers@vrfy.org>
*
* 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 version 2 of the License.
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
static void remove_trailing_chars(char *path, char c)
{
size_t len;
len = strlen(path);
while (len > 0 && path[len-1] == c)
path[--len] = '\0';
}
/* count of characters used to encode one unicode char */
static int utf8_encoded_expected_len(const char *str)
{
unsigned char c = (unsigned char)str[0];
if (c < 0x80)
return 1;
if ((c & 0xe0) == 0xc0)
return 2;
if ((c & 0xf0) == 0xe0)
return 3;
if ((c & 0xf8) == 0xf0)
return 4;
if ((c & 0xfc) == 0xf8)
return 5;
if ((c & 0xfe) == 0xfc)
return 6;
return 0;
}
/* decode one unicode char */
static int utf8_encoded_to_unichar(const char *str)
{
int unichar;
int len;
int i;
len = utf8_encoded_expected_len(str);
switch (len) {
case 1:
return (int)str[0];
case 2:
unichar = str[0] & 0x1f;
break;
case 3:
unichar = (int)str[0] & 0x0f;
break;
case 4:
unichar = (int)str[0] & 0x07;
break;
case 5:
unichar = (int)str[0] & 0x03;
break;
case 6:
unichar = (int)str[0] & 0x01;
break;
default:
return -1;
}
for (i = 1; i < len; i++) {
if (((int)str[i] & 0xc0) != 0x80)
return -1;
unichar <<= 6;
unichar |= (int)str[i] & 0x3f;
}
return unichar;
}
/* expected size used to encode one unicode char */
static int utf8_unichar_to_encoded_len(int unichar)
{
if (unichar < 0x80)
return 1;
if (unichar < 0x800)
return 2;
if (unichar < 0x10000)
return 3;
if (unichar < 0x200000)
return 4;
if (unichar < 0x4000000)
return 5;
return 6;
}
/* check if unicode char has a valid numeric range */
static int utf8_unichar_valid_range(int unichar)
{
if (unichar > 0x10ffff)
return 0;
if ((unichar & 0xfffff800) == 0xd800)
return 0;
if ((unichar > 0xfdcf) && (unichar < 0xfdf0))
return 0;
if ((unichar & 0xffff) == 0xffff)
return 0;
return 1;
}
/* validate one encoded unicode char and return its length */
static int utf8_encoded_valid_unichar(const char *str)
{
int len;
int unichar;
int i;
len = utf8_encoded_expected_len(str);
if (len == 0)
return -1;
/* ascii is valid */
if (len == 1)
return 1;
/* check if expected encoded chars are available */
for (i = 0; i < len; i++)
if ((str[i] & 0x80) != 0x80)
return -1;
unichar = utf8_encoded_to_unichar(str);
/* check if encoded length matches encoded value */
if (utf8_unichar_to_encoded_len(unichar) != len)
return -1;
/* check if value has valid range */
if (!utf8_unichar_valid_range(unichar))
return -1;
return len;
}
/* replace everything but whitelisted plain ascii and valid utf8 */
static int replace_untrusted_chars(char *str)
{
size_t i = 0;
int replaced = 0;
while (str[i] != '\0') {
int len;
/* valid printable ascii char */
if ((str[i] >= '0' && str[i] <= '9') ||
(str[i] >= 'A' && str[i] <= 'Z') ||
(str[i] >= 'a' && str[i] <= 'z') ||
strchr(" #$%+-./:=?@_,", str[i])) {
i++;
continue;
}
/* valid utf8 is accepted */
len = utf8_encoded_valid_unichar(&str[i]);
if (len > 1) {
i += len;
continue;
}
/* everything else is garbage */
str[i] = '_';
i++;
replaced++;
}
return replaced;
}
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