diff options
Diffstat (limited to 'alsactl/init_utils_string.c')
| -rw-r--r-- | alsactl/init_utils_string.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/alsactl/init_utils_string.c b/alsactl/init_utils_string.c new file mode 100644 index 0000000..2598e9f --- /dev/null +++ b/alsactl/init_utils_string.c @@ -0,0 +1,194 @@ +/* + * 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 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; +} + +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; +} |