From 765babd0cce3c9a133c4bd9083ae8d057f213e04 Mon Sep 17 00:00:00 2001
From: Matt Muller <mamuller@amazon.com>
Date: Wed, 13 Sep 2023 15:24:39 -0400
Subject: [PATCH] Fix endpoint matcher host label validation

---
 gems/aws-sdk-core/CHANGELOG.md                |  2 ++
 .../lib/aws-sdk-core/endpoints/matchers.rb    | 22 +++++++++++--------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/gems/aws-sdk-core/CHANGELOG.md b/gems/aws-sdk-core/CHANGELOG.md
index eaaaef73bc4..e4f4de54b7c 100644
--- a/gems/aws-sdk-core/CHANGELOG.md
+++ b/gems/aws-sdk-core/CHANGELOG.md
@@ -1,6 +1,8 @@
 Unreleased Changes
 ------------------
 
+* Issue - Fix host label validation in endpoint matchers.
+
 3.181.0 (2023-08-22)
 ------------------
 
diff --git a/gems/aws-sdk-core/lib/aws-sdk-core/endpoints/matchers.rb b/gems/aws-sdk-core/lib/aws-sdk-core/endpoints/matchers.rb
index 5c6bf2c04d7..9ae20e18d59 100644
--- a/gems/aws-sdk-core/lib/aws-sdk-core/endpoints/matchers.rb
+++ b/gems/aws-sdk-core/lib/aws-sdk-core/endpoints/matchers.rb
@@ -79,11 +79,11 @@ def self.valid_host_label?(value, allow_sub_domains = false)
         return false if value.empty?
 
         if allow_sub_domains
-          labels = value.split('.')
+          labels = value.split('.', -1)
           return labels.all? { |l| valid_host_label?(l) }
         end
 
-        value =~ /\A(?!-)[a-zA-Z0-9-]{1,63}(?<!-)\z/
+        value.match?(/\A(?!-)[a-zA-Z0-9-]{1,63}(?<!-)\z/)
       end
 
       # AWS
@@ -114,13 +114,17 @@ def self.aws_parse_arn(value)
 
       # aws.isVirtualHostableS3Bucket(value: string, allowSubDomains: bool) bool
       def self.aws_virtual_hostable_s3_bucket?(value, allow_sub_domains = false)
-        !!(value.size < 64 &&
-          # regular naming rules
-          value =~ /^[a-z0-9][a-z0-9\-#{'.' if allow_sub_domains}]+[a-z0-9]$/ &&
-          # not IP address
-          value !~ /(\d+\.){3}\d+/ &&
-          # no dash and hyphen together
-          value !~ /[.-]{2}/)
+        return false if value.empty?
+
+        if allow_sub_domains
+          labels = value.split('.', -1)
+          return labels.all? { |l| aws_virtual_hostable_s3_bucket?(l) }
+        end
+
+        # must be between 3 and 63 characters long, no uppercase
+        value.match?(/\A(?!-)[a-z0-9-]{3,63}(?<!-)\z/) &&
+          # not an IP address
+          value !~ /(\d+\.){3}\d+/
       end
     end
   end