Attachment 16310 Details for Bug 14553 – patch for v4.13 branch

[patch] patch for v4.13 branch

dnspython-2.0.0-support-v4.13.patch (text/plain), 5.23 KB, created by Alexander Bokovoy on 2020-10-27 07:50:08 UTC

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Creator: Alexander Bokovoy

Created: 2020-10-27 07:50:08 UTC

Size: 5.23 KB

patch

obsolete

>From 46278ee57f9082b0c78d51dd0a530ba1cf3dffc9 Mon Sep 17 00:00:00 2001
>From: Alexander Bokovoy <ab@samba.org>
>Date: Sat, 24 Oct 2020 12:17:44 +0300
>Subject: [PATCH] DNS Resolver: support both dnspython before and after 2.0.0
>
>`dnspython` 2.0.0 has many changes and several deprecations like:
>
>```
>> dns.resolver.resolve() has been added, allowing control of whether
>search lists are used. dns.resolver.query() is retained for backwards
>compatibility, but deprecated. The default for search list behavior can
>be set at in the resolver object with the use_search_by_default
>parameter. The default is False.
>
>> dns.resolver.resolve_address() has been added, allowing easy
>address-to-name lookups.
>```
>
>The new class `DNSResolver`:
>- provides the compatibility layer
>- defaults the previous behavior (the search list configured in the
>  system's resolver configuration is used for relative names)
>- defaults lifetime to 15sec (determines the number of seconds
>  to spend trying to get an answer to the question)
>
>The compatibility shim was developed by Stanislav Levin for FreeIPA and
>adopted for Samba by Alexander Bokovoy.
>
>BUG: https://bugzilla.samba.org/show_bug.cgi?id=14553
>
>Signed-off-by: Stanislav Levin <slev@altlinux.org>
>Signed-off-by: Alexander Bokovoy <ab@samba.org>
>Reviewed-by: Andreas Schneider <asn@samba.org>
>(cherry picked from commit 183d5d63f4b40accda3b3ffc980fea391612f964)
>---
> python/samba/dnsresolver.py           | 68 +++++++++++++++++++++++++++
> source4/scripting/bin/samba_dnsupdate |  5 +-
> 2 files changed, 71 insertions(+), 2 deletions(-)
> create mode 100644 python/samba/dnsresolver.py
>
>diff --git a/python/samba/dnsresolver.py b/python/samba/dnsresolver.py
>new file mode 100644
>index 00000000000..a627555a855
>--- /dev/null
>+++ b/python/samba/dnsresolver.py
>@@ -0,0 +1,68 @@
>+# Samba wrapper for DNS resolvers
>+#
>+# Copyright (C) Stanislav Levin <slev@altlinux.org>
>+# Copyright (C) Alexander Bokovoy <ab@samba.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; either version 3 of the License, or
>+# (at your option) any later version.
>+#
>+# 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, see <http://www.gnu.org/licenses/>.
>+#
>+
>+import dns.resolver
>+import dns.rdatatype
>+import dns.reversename
>+
>+class DNSResolver(dns.resolver.Resolver):
>+    """DNS stub resolver compatible with both dnspython < 2.0.0
>+    and dnspython >= 2.0.0.
>+
>+    Set `use_search_by_default` attribute to `True`, which
>+    determines the default for whether the search list configured
>+    in the system's resolver configuration is used for relative
>+    names, and whether the resolver's domain may be added to relative
>+    names.
>+
>+    Increase the default lifetime which determines the number of seconds
>+    to spend trying to get an answer to the question. dnspython 2.0.0
>+    changes this to 5sec, while the previous one was 30sec.
>+    """
>+    def __init__(self, *args, **kwargs):
>+        super().__init__(*args, **kwargs)
>+        self.reset_defaults()
>+        self.resolve = getattr(super(), "resolve", self.query)
>+        self.resolve_address = getattr(
>+            super(),
>+            "resolve_address",
>+            self._resolve_address
>+        )
>+
>+    def reset_defaults(self):
>+        self.use_search_by_default = True
>+        # the default is 5sec
>+        self.lifetime = 15
>+
>+    def reset(self):
>+        super().reset()
>+        self.reset_defaults()
>+
>+    def _resolve_address(self, ip_address, *args, **kwargs):
>+        """Query nameservers for PTR records.
>+
>+        :param ip_address: IPv4 or IPv6 address
>+        :type ip_address: str
>+        """
>+        return self.resolve(
>+            dns.reversename.from_address(ip_address),
>+            rdtype=dns.rdatatype.PTR,
>+            *args,
>+            **kwargs,
>+        )
>diff --git a/source4/scripting/bin/samba_dnsupdate b/source4/scripting/bin/samba_dnsupdate
>index 44eb1cadd27..fe04ce71338 100755
>--- a/source4/scripting/bin/samba_dnsupdate
>+++ b/source4/scripting/bin/samba_dnsupdate
>@@ -53,6 +53,7 @@ from samba.compat import get_string
> from samba.compat import text_type
> import ldb
> 
>+from samba.dnsresolver import DNSResolver
> import dns.resolver
> import dns.exception
> 
>@@ -259,7 +260,7 @@ def hostname_match(h1, h2):
> 
> def get_resolver(d=None):
>     resolv_conf = os.getenv('RESOLV_CONF', default='/etc/resolv.conf')
>-    resolver = dns.resolver.Resolver(filename=resolv_conf, configure=True)
>+    resolver = DNSResolver(filename=resolv_conf, configure=True)
> 
>     if d is not None and d.nameservers != []:
>         resolver.nameservers = d.nameservers
>@@ -271,7 +272,7 @@ def check_one_dns_name(name, name_type, d=None):
>     if d and not d.nameservers:
>         d.nameservers = resolver.nameservers
>     # dns.resolver.Answer
>-    return resolver.query(name, name_type)
>+    return resolver.resolve(name, name_type)
> 
> def check_dns_name(d):
>     """check that a DNS entry exists."""
>-- 
>2.28.0
>

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asn: review+

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Attachments on bug 14553: 16310