diff options
Diffstat (limited to 'resolv/res_comp.c')
| -rw-r--r-- | resolv/res_comp.c | 208 |
1 files changed, 117 insertions, 91 deletions
diff --git a/resolv/res_comp.c b/resolv/res_comp.c index 1b47a5dfbe..c35a9fad01 100644 --- a/resolv/res_comp.c +++ b/resolv/res_comp.c @@ -1,3 +1,21 @@ +/* Domain name processing functions. + Copyright (C) 1995-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + /* * Copyright (c) 1985, 1993 * The Regents of the University of California. All rights reserved. @@ -121,110 +139,118 @@ dn_skipname(const u_char *ptr, const u_char *eom) { } libresolv_hidden_def (dn_skipname) -/* - * Verify that a domain name uses an acceptable character set. - */ +/* Return true if the string consists of printable ASCII characters + only. */ +static bool +printable_string (const char *dn) +{ + while (true) + { + char ch = *dn; + if (ch == '\0') + return true; + if (ch <= ' ' || ch > '~') + return false; + ++dn; + } +} -/* - * Note the conspicuous absence of ctype macros in these definitions. On - * non-ASCII hosts, we can't depend on string literals or ctype macros to - * tell us anything about network-format data. The rest of the BIND system - * is not careful about this, but for some reason, we're doing it right here. - */ -#define PERIOD 0x2e -#define hyphenchar(c) ((c) == 0x2d) -#define underscorechar(c) ((c) == 0x5f) -#define bslashchar(c) ((c) == 0x5c) -#define periodchar(c) ((c) == PERIOD) -#define asterchar(c) ((c) == 0x2a) -#define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \ - || ((c) >= 0x61 && (c) <= 0x7a)) -#define digitchar(c) ((c) >= 0x30 && (c) <= 0x39) - -#define borderchar(c) (alphachar(c) || digitchar(c)) -#define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c)) -#define domainchar(c) ((c) > 0x20 && (c) < 0x7f) +/* Return true if DN points to a name consisting only of [0-9a-zA-Z_-] + characters. DN must be in DNS wire format, without + compression. */ +static bool +binary_hnok (const unsigned char *dn) +{ + while (true) + { + size_t label_length = *dn; + if (label_length == 0) + break; + ++dn; + const unsigned char *label_end = dn + label_length; + do + { + unsigned char ch = *dn; + if (!(('0' <= ch && ch <= '9') + || ('A' <= ch && ch <= 'Z') + || ('a' <= ch && ch <= 'z') + || ch == '-' || ch == '_')) + return false; + ++dn; + } + while (dn < label_end); + } + return true; +} + +/* Return true if the binary domain name has a first labels which + starts with '-'. */ +static inline bool +binary_leading_dash (const unsigned char *dn) +{ + return dn[0] > 0 && dn[1] == '-'; +} +/* Return 1 if res_hnok is a valid host name. Labels must only + contain [0-9a-zA-Z_-] characters, and the name must not start with + a '-'. The latter is to avoid confusion with program options. */ int -res_hnok(const char *dn) { - int pch = PERIOD, ch = *dn++; - - while (ch != '\0') { - int nch = *dn++; - - if (periodchar(ch)) { - (void)NULL; - } else if (periodchar(pch)) { - if (!borderchar(ch)) - return (0); - } else if (periodchar(nch) || nch == '\0') { - if (!borderchar(ch)) - return (0); - } else { - if (!middlechar(ch)) - return (0); - } - pch = ch, ch = nch; - } - return (1); +res_hnok (const char *dn) +{ + unsigned char buf[NS_MAXCDNAME]; + if (!printable_string (dn) + || ns_name_pton (dn, buf, sizeof (buf)) < 0 + || binary_leading_dash (buf)) + return 0; + return binary_hnok (buf); } libresolv_hidden_def (res_hnok) -/* - * hostname-like (A, MX, WKS) owners can have "*" as their first label - * but must otherwise be as a host name. - */ +/* Hostname-like (A, MX, WKS) owners can have "*" as their first label + but must otherwise be as a host name. */ int -res_ownok(const char *dn) { - if (asterchar(dn[0])) { - if (periodchar(dn[1])) - return (res_hnok(dn+2)); - if (dn[1] == '\0') - return (1); - } - return (res_hnok(dn)); +res_ownok (const char *dn) +{ + unsigned char buf[NS_MAXCDNAME]; + if (!printable_string (dn) + || ns_name_pton (dn, buf, sizeof (buf)) < 0 + || binary_leading_dash (buf)) + return 0; + if (buf[0] == 1 && buf [1] == '*') + /* Skip over the leading "*." part. */ + return binary_hnok (buf + 2); + else + return binary_hnok (buf); } -/* - * SOA RNAMEs and RP RNAMEs can have any printable character in their first - * label, but the rest of the name has to look like a host name. - */ +/* SOA RNAMEs and RP RNAMEs can have any byte in their first label, + but the rest of the name has to look like a host name. */ int -res_mailok(const char *dn) { - int ch, escaped = 0; - - /* "." is a valid missing representation */ - if (*dn == '\0') - return (1); - - /* otherwise <label>.<hostname> */ - while ((ch = *dn++) != '\0') { - if (!domainchar(ch)) - return (0); - if (!escaped && periodchar(ch)) - break; - if (escaped) - escaped = 0; - else if (bslashchar(ch)) - escaped = 1; - } - if (periodchar(ch)) - return (res_hnok(dn)); - return (0); +res_mailok (const char *dn) +{ + unsigned char buf[NS_MAXCDNAME]; + if (!printable_string (dn) + || ns_name_pton (dn, buf, sizeof (buf)) < 0) + return 0; + unsigned char label_length = buf[0]; + /* "." is a valid missing representation */ + if (label_length == 0) + return 1; + /* Skip over the first label. */ + unsigned char *tail = buf + 1 + label_length; + if (*tail == 0) + /* More than one label is required (except for "."). */ + return 0; + return binary_hnok (tail); } -/* - * This function is quite liberal, since RFC 1034's character sets are only - * recommendations. - */ +/* Return 1 if DN is a syntactically valid domain name. Empty names + are accepted. */ int -res_dnok(const char *dn) { - int ch; - - while ((ch = *dn++) != '\0') - if (!domainchar(ch)) - return (0); - return (1); +res_dnok (const char *dn) +{ + unsigned char buf[NS_MAXCDNAME]; + return printable_string (dn) && ns_name_pton (dn, buf, sizeof (buf)) >= 0; } libresolv_hidden_def (res_dnok) |