From 5b13ecb830cdec338b514b9ed8c2c559c2f05223 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Sun, 28 Aug 2005 13:49:32 +0200 Subject: add uft8 validation for safe volume label exporting We will not support any other character encoding than plain ascii or utf8 for volume labels. All invalid utf8 and non-ascii characters are substituted for security reasons. No options, no fancy heuristics. Signed-off-by: Kay Sievers --- udev_utils_string.c | 243 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 243 insertions(+) create mode 100644 udev_utils_string.c (limited to 'udev_utils_string.c') diff --git a/udev_utils_string.c b/udev_utils_string.c new file mode 100644 index 0000000000..a30181e760 --- /dev/null +++ b/udev_utils_string.c @@ -0,0 +1,243 @@ +/* + * udev_utils_string.c - string manipulation + * + * Copyright (C) 2004-2005 Kay Sievers + * + * 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., + * 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ + + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "udev_libc_wrapper.h" +#include "udev.h" +#include "logging.h" +#include "udev_utils.h" +#include "list.h" + +/* compare string with pattern (like fnmatch(), supports * ? [0-9] [!A-Z]) */ +int strcmp_pattern(const char *p, const char *s) +{ + if (s[0] == '\0') { + while (p[0] == '*') + p++; + return (p[0] != '\0'); + } + switch (p[0]) { + case '[': + { + int not = 0; + p++; + if (p[0] == '!') { + not = 1; + p++; + } + while ((p[0] != '\0') && (p[0] != ']')) { + int match = 0; + if (p[1] == '-') { + if ((s[0] >= p[0]) && (s[0] <= p[2])) + match = 1; + p += 3; + } else { + match = (p[0] == s[0]); + p++; + } + if (match ^ not) { + while ((p[0] != '\0') && (p[0] != ']')) + p++; + if (p[0] == ']') + return strcmp_pattern(p+1, s+1); + } + } + } + break; + case '*': + if (strcmp_pattern(p, s+1)) + return strcmp_pattern(p+1, s); + return 0; + case '\0': + if (s[0] == '\0') { + return 0; + } + break; + default: + if ((p[0] == s[0]) || (p[0] == '?')) + return strcmp_pattern(p+1, s+1); + break; + } + return 1; +} + +int string_is_true(const char *str) +{ + if (strcasecmp(str, "true") == 0) + return 1; + if (strcasecmp(str, "yes") == 0) + return 1; + if (strcasecmp(str, "1") == 0) + return 1; + return 0; +} + +void remove_trailing_char(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 */ +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; +} + +void replace_untrusted_chars(char *string) +{ + size_t len; + + for (len = 0; string[len] != '\0'; len++) { + if (strchr(";,~\\()\'", string[len])) + string[len] = '_'; + } +} -- cgit v1.2.3-54-g00ecf