You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
322 lines
9.5 KiB
322 lines
9.5 KiB
commit c0a25aa92b612786f4e45292c4aee1d7d47123f8 |
|
Author: Florian Weimer <fweimer@redhat.com> |
|
Date: Sat Nov 11 11:51:08 2017 +0100 |
|
|
|
resolv: More precise checks in res_hnok, res_dnok [BZ #22409] [BZ #22412] |
|
|
|
res_hnok rejected some host names used on the Internet, such as |
|
www-.example.com. res_hnok and res_dnok failed to perform basic syntax |
|
checking on DNS domain names. |
|
|
|
Also fix res_mailok, res_ownok. |
|
|
|
diff --git a/resolv/res_comp.c b/resolv/res_comp.c |
|
index ffb2ed59147d3680..79760e891f607daa 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) |
|
|
|
diff --git a/resolv/tst-res_hnok.c b/resolv/tst-res_hnok.c |
|
index 9c923038218e965c..314477a2ce2661c0 100644 |
|
--- a/resolv/tst-res_hnok.c |
|
+++ b/resolv/tst-res_hnok.c |
|
@@ -51,19 +51,31 @@ static const struct test_case tests[] = |
|
{ |
|
{ "", allok }, |
|
{ ".", allok }, |
|
+ { "..", 0 }, |
|
{ "www", allnomailok }, |
|
+ { "www.", allnomailok }, |
|
{ "example", allnomailok }, |
|
{ "example.com", allok }, |
|
{ "www.example.com", allok }, |
|
{ "www.example.com.", allok }, |
|
+ { "www-.example.com.", allok }, |
|
+ { "www.-example.com.", allok }, |
|
{ "*.example.com", dnok | mailok | ownok }, |
|
{ "-v", dnok }, |
|
{ "-v.example.com", mailok | dnok }, |
|
{ "**.example.com", dnok | mailok }, |
|
+ { "www.example.com\\", 0 }, |
|
{ STRING63, allnomailok }, |
|
+ { STRING63 ".", allnomailok }, |
|
+ { STRING63 "\\.", 0 }, |
|
+ { STRING63 "z", 0 }, |
|
{ STRING63 ".example.com", allok }, |
|
{ STRING63 "." STRING63 "." STRING63 "." STRING60 "z", allok }, |
|
+ { STRING63 "." STRING63 "." STRING63 "." STRING60 "z.", allok }, |
|
+ { STRING63 "." STRING63 "." STRING63 "." STRING60 "zz", 0 }, |
|
+ { STRING63 "." STRING63 "." STRING63 "." STRING60 "zzz", 0 }, |
|
{ "hostmaster@mail.example.com", dnok | mailok }, |
|
+ { "hostmaster\\@mail.example.com", dnok | mailok }, |
|
{ "with whitespace", 0 }, |
|
{ "with\twhitespace", 0 }, |
|
{ "with\nwhitespace", 0 }, |
|
@@ -116,6 +128,12 @@ one_char (const char *prefix, const char *accepted, const char *suffix, |
|
} |
|
} |
|
|
|
+#define LETTERSDIGITS \ |
|
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" |
|
+ |
|
+#define PRINTABLE \ |
|
+ "!\"#$%&'()*+,/:;<=>?@[\\]^`{|}~" |
|
+ |
|
static int |
|
do_test (void) |
|
{ |
|
@@ -131,20 +149,18 @@ do_test (void) |
|
} |
|
|
|
one_char |
|
- ("", "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.", |
|
- "", "res_hnok", res_hnok); |
|
+ ("", LETTERSDIGITS "._", "", "res_hnok", res_hnok); |
|
one_char |
|
("middle", |
|
- "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.-_", |
|
+ LETTERSDIGITS ".-_\\", /* "middle\\suffix" == "middlesuffix", so good. */ |
|
"suffix", "res_hnok", res_hnok); |
|
one_char |
|
("middle", |
|
- "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.-_" |
|
- "!\"#$%&'()*+,/:;<=>?@[\\]^`{|}~", |
|
+ LETTERSDIGITS ".-_" PRINTABLE, |
|
"suffix.example", "res_mailok", res_mailok); |
|
one_char |
|
("mailbox.middle", |
|
- "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.-_", |
|
+ LETTERSDIGITS ".-_\\", |
|
"suffix.example", "res_mailok", res_mailok); |
|
|
|
return 0;
|
|
|