From 9cdd829299d6a60a92466f62b91cba74c366d827 Mon Sep 17 00:00:00 2001
From: jmhunter <19241458+jmhunter@users.noreply.github.com>
Date: Wed, 17 Mar 2021 09:36:27 +0000
Subject: [PATCH 1/2] Update NAME_REGEX as per bug #1916325

The NAME_REGEX currently used is "[a-z_][a-z0-9_-]*" which does correctly prevent hostnames starting with a hyphen.. but also prevents otherwise perfectly valid hostnames that start with a number. (Interestingly, an underscore is not defined as a valid hostname character, but is included as valid in the regex, I'm not sure why this is included but am leaving it in for backwards compatibility)

This patch adds 0-9 as valid characters at the start of a hostname, as per https://man7.org/linux/man-pages/man7/hostname.7.html#:~:text=Valid%20characters%20for%20hostnames%20are,to%20an%20address%20for%20use.
       Each element of the hostname must be from 1 to 63 characters long
       and the entire hostname, including the dots, can be at most 253
       characters long. Valid characters for hostnames are ASCII(7)
       letters from a to z, the digits from 0 to 9, and the hyphen (-).
       A hostname may not start with a hyphen.
---
 subiquity/ui/views/identity.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/subiquity/ui/views/identity.py b/subiquity/ui/views/identity.py
index fcab46c7..e1760301 100644
--- a/subiquity/ui/views/identity.py
+++ b/subiquity/ui/views/identity.py
@@ -107,8 +107,8 @@ class IdentityForm(Form):
                 "Server name too long, must be less than {limit}"
                 ).format(limit=HOSTNAME_MAXLEN)
 
-        if not re.match(r'[a-z_][a-z0-9_-]*', self.hostname.value):
-            return _("Hostname must match NAME_REGEX, i.e. [a-z_][a-z0-9_-]*")
+        if not re.match(r'[a-z0-9_][a-z0-9_-]*', self.hostname.value):
+            return _("Hostname must match NAME_REGEX, i.e. [a-z0-9_][a-z0-9_-]*")
 
     def validate_username(self):
         username = self.username.value

From c65c322fc659f452e2e16aa136b3afae45482b84 Mon Sep 17 00:00:00 2001
From: Jonathan Hunter <19241458+jmhunter@users.noreply.github.com>
Date: Wed, 17 Mar 2021 20:09:41 +0000
Subject: [PATCH 2/2] Add variables to hold username and hostname regex

Also adjust displayed message to match.

Tested locally using 'make dryrun'
---
 subiquity/ui/views/identity.py | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/subiquity/ui/views/identity.py b/subiquity/ui/views/identity.py
index e1760301..de41fca7 100644
--- a/subiquity/ui/views/identity.py
+++ b/subiquity/ui/views/identity.py
@@ -40,9 +40,11 @@ from subiquity.common.types import IdentityData
 log = logging.getLogger("subiquity.views.identity")
 
 HOSTNAME_MAXLEN = 64
+HOSTNAME_REGEX = r'[a-z0-9_][a-z0-9_-]*'
 REALNAME_MAXLEN = 160
 SSH_IMPORT_MAXLEN = 256 + 3  # account for lp: or gh:
 USERNAME_MAXLEN = 32
+USERNAME_REGEX = r'[a-z_][a-z0-9_-]*'
 
 
 class RealnameEditor(StringEditor, WantsToKnowFormField):
@@ -107,8 +109,9 @@ class IdentityForm(Form):
                 "Server name too long, must be less than {limit}"
                 ).format(limit=HOSTNAME_MAXLEN)
 
-        if not re.match(r'[a-z0-9_][a-z0-9_-]*', self.hostname.value):
-            return _("Hostname must match NAME_REGEX, i.e. [a-z0-9_][a-z0-9_-]*")
+        if not re.match(HOSTNAME_REGEX, self.hostname.value):
+            return _(
+                "Hostname must match HOSTNAME_REGEX: " + HOSTNAME_REGEX)
 
     def validate_username(self):
         username = self.username.value
@@ -121,7 +124,8 @@ class IdentityForm(Form):
                 ).format(limit=USERNAME_MAXLEN)
 
         if not re.match(r'[a-z_][a-z0-9_-]*', username):
-            return _("Username must match NAME_REGEX, i.e. [a-z_][a-z0-9_-]*")
+            return _(
+                "Username must match USERNAME_REGEX: " + USERNAME_REGEX)
 
         if username in self.reserved_usernames:
             return _(