resolv: Rename res_comp.c to res-name-checking.c and move into libc

This reflects what the remaining functions in the file do.

The __res_dnok, __res_hnok, __res_mailok, __res_ownok were moved
with the script, using --no-new-version, and turned into compat
symbols.  __libc_res_dnok@@GLIBC_PRIVATE and
__libc_res_hnok@@GLIBC_PRIVATE are added for internal use, to avoid
accidentally binding to compatibility symbols.  The new public
symbols res_dnok, res_hnok, res_mailok, res_ownok were added using
make update-all-abi.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 220 insertions, 0 deletions

diff --git a/resolv/res-name-checking.c b/resolv/res-name-checking.c
new file mode 100644
index 0000000000..2c603494fa
--- /dev/null
+++ b/resolv/res-name-checking.c
@@ -0,0 +1,220 @@
+/* Syntax checking for DNS domain names.
+   Copyright (C) 1995-2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ * Copyright (c) 1985, 1993
+ *    The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Portions Copyright (c) 1993 by Digital Equipment Corporation.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies, and that
+ * the name of Digital Equipment Corporation not be used in advertising or
+ * publicity pertaining to distribution of the document or software without
+ * specific, written prior permission.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
+ * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+/*
+ * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+#include <arpa/nameser.h>
+#include <resolv.h>
+#include <shlib-compat.h>
+
+/* 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;
+    }
+}
+
+/* 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)
+{
+  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);
+}
+versioned_symbol (libc, ___res_hnok, res_hnok, GLIBC_2_34);
+versioned_symbol (libc, ___res_hnok, __libc_res_hnok, GLIBC_PRIVATE);
+libc_hidden_ver (___res_hnok, __libc_res_hnok)
+#if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_34)
+compat_symbol (libresolv, ___res_hnok, __res_hnok, GLIBC_2_0);
+#endif
+
+/* 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)
+{
+  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);
+}
+versioned_symbol (libc, ___res_ownok, res_ownok, GLIBC_2_34);
+#if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_34)
+compat_symbol (libresolv, ___res_ownok, __res_ownok, GLIBC_2_0);
+#endif
+
+/* 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)
+{
+  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);
+}
+versioned_symbol (libc, ___res_mailok, res_mailok, GLIBC_2_34);
+#if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_34)
+compat_symbol (libresolv, ___res_mailok, __res_mailok, GLIBC_2_0);
+#endif
+
+/* Return 1 if DN is a syntactically valid domain name.  Empty names
+   are accepted.  */
+int
+___res_dnok (const char *dn)
+{
+  unsigned char buf[NS_MAXCDNAME];
+  return printable_string (dn) && __ns_name_pton (dn, buf, sizeof (buf)) >= 0;
+}
+versioned_symbol (libc, ___res_dnok, res_dnok, GLIBC_2_34);
+versioned_symbol (libc, ___res_dnok, __libc_res_dnok, GLIBC_PRIVATE);
+libc_hidden_ver (___res_dnok, __libc_res_dnok)
+#if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_34)
+compat_symbol (libresolv, ___res_dnok, __res_dnok, GLIBC_2_0);
+#endif