From: "kanashiro (Lucas Kanashiro)" <noreply@...>
Date: 2021-09-13T22:32:44+00:00
Subject: [ruby-core:105232] [Ruby master Bug#18165] resolv: IPv6 link local addresses do not accept dash as a valid zone_id character

Issue #18165 has been updated by kanashiro (Lucas Kanashiro).

File 0001-Make-resolv-accept-dash-in-zone_id-of-IPv6-link-loca.patch added

The mentioned patch is attached.

----------------------------------------
Bug #18165: resolv: IPv6 link local addresses do not accept dash as a valid zone_id character
https://bugs.ruby-lang.org/issues/18165#change-93639

* Author: kanashiro (Lucas Kanashiro)
* Status: Open
* Priority: Normal
* ruby -v: 3.0.2
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
The support for IPv6 link local addresses was added to resolv [here](https://bugs.ruby-lang.org/projects/ruby-master/repository/git/revisions/2f12af42f7f26d570219b87a89294532a86a8ae2).

However, it does not take into account a `zone_id` with a dash (`-`) in it, just digits and letters (uppercase and lowercase). One could use the name of the network interface as `zone_id` and this one might contain a dash. For instance, in my system running Ubuntu I have `tap-5f507d638e8` and bridges like `br-dd8d2dfaa7eb`, those could be used as `zone_id`.

According to the [RFC](https://datatracker.ietf.org/doc/html/rfc4007#section-11) it is not mandatory to accept dash as a valid `zone_id` character but I believe this is a valid use case and resolv should support it. I found this out trying to build version `3.0.2` in Debian, and since my system contains some network interfaces with dash, the `TestResolvAddr::test_valid_socket_ip_address_list` was failing:

```
Expected /(?:(?-mix:\A((?x-mi:0
               |1(?:[0-9][0-9]?)?
               |2(?:[0-4][0-9]?|5[0-5]?|[6-9])?
               |[3-9][0-9]?))\.((?x-mi:0
               |1(?:[0-9][0-9]?)?
               |2(?:[0-4][0-9]?|5[0-5]?|[6-9])?
               |[3-9][0-9]?))\.((?x-mi:0
               |1(?:[0-9][0-9]?)?
               |2(?:[0-4][0-9]?|5[0-5]?|[6-9])?
               |[3-9][0-9]?))\.((?x-mi:0
               |1(?:[0-9][0-9]?)?
               |2(?:[0-4][0-9]?|5[0-5]?|[6-9])?
               |[3-9][0-9]?))\z))|(?:(?x-mi:
      (?:(?x-mi:\A
      (?:[0-9A-Fa-f]{1,4}:){7}
         [0-9A-Fa-f]{1,4}
      \z)) |
      (?:(?x-mi:\A
      ((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::
      ((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)
      \z)) |
      (?:(?x-mi:\A
      ((?:[0-9A-Fa-f]{1,4}:){6,6})
      (\d+)\.(\d+)\.(\d+)\.(\d+)
      \z)) |
      (?:(?x-mi:\A
      ((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::
      ((?:[0-9A-Fa-f]{1,4}:)*)
      (\d+)\.(\d+)\.(\d+)\.(\d+)
      \z)) |
      (?:(?x-mi:\A
      [Ff][Ee]80
      (?::[0-9A-Fa-f]{1,4}){7}
      %[0-9A-Za-z]+
      \z)) |
      (?:(?x-mi:\A
      [Ff][Ee]80:
      (?:
        ((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::
        ((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)
        |
        :((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)
      )?
      :[0-9A-Fa-f]{1,4}%[0-9A-Za-z.]+
      \z))
      ))/ to match "fe80::4cd3:c6ff:fed2:9529%tap-4845bb4a54b".
```

Applying the patch below fixed the issue for me:

``` diff
diff --git a/lib/resolv.rb b/lib/resolv.rb
index b69c704..5de6a1f 100644
--- a/lib/resolv.rb
+++ b/lib/resolv.rb
@@ -2464,7 +2464,7 @@ class Resolv
     Regex_8HexLinkLocal = /\A
       [Ff][Ee]80
       (?::[0-9A-Fa-f]{1,4}){7}
-      %[0-9A-Za-z]+
+      %[0-9A-Za-z\-]+
       \z/x
 
     ##
@@ -2478,7 +2478,7 @@ class Resolv
         |
         :((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)
       )?
-      :[0-9A-Fa-f]{1,4}%[0-9A-Za-z.]+
+      :[0-9A-Fa-f]{1,4}%[0-9A-Za-z.\-]+
       \z/x
 
     ##
```


---Files--------------------------------
0001-Make-resolv-accept-dash-in-zone_id-of-IPv6-link-loca.patch (958 Bytes)


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