From 5354d4f0025aba4649e32fa63d4894b430d19d1a Mon Sep 17 00:00:00 2001
From: Andrew Mason <andrew@planetscale.com>
Date: Tue, 28 Mar 2023 13:46:08 -0400
Subject: [PATCH] broader restrictions via allow-list

Signed-off-by: Andrew Mason <andrew@planetscale.com>
---
 changelog/17.0/17.0.0/summary.md |  3 +-
 go/vt/topo/keyspace.go           |  8 +++---
 go/vt/topo/keyspace_test.go      | 48 ++++++++++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/changelog/17.0/17.0.0/summary.md b/changelog/17.0/17.0.0/summary.md
index 1c1ec2e1daa..4e9a0e25275 100644
--- a/changelog/17.0/17.0.0/summary.md
+++ b/changelog/17.0/17.0.0/summary.md
@@ -57,8 +57,7 @@ Prior to v17, it was possible to create a keyspace with invalid characters, whic
 
 Now, the TopoServer's `GetKeyspace` and `CreateKeyspace` methods return an error if given an invalid name.
 
-Keyspace names may no longer contain the following characters:
-- Forward slash ("/").
+Keyspace names may now only contain alphanumerics, dashes (`-`), and underscores (`_`), and must begin with an alphabetical character.
 
 ### <a id="new-flag"/> New command line flags and behavior
 
diff --git a/go/vt/topo/keyspace.go b/go/vt/topo/keyspace.go
index dc0af6e11ec..8b62972ad48 100755
--- a/go/vt/topo/keyspace.go
+++ b/go/vt/topo/keyspace.go
@@ -18,7 +18,7 @@ package topo
 
 import (
 	"path"
-	"strings"
+	"regexp"
 
 	"context"
 
@@ -54,15 +54,15 @@ func (ki *KeyspaceInfo) SetKeyspaceName(name string) {
 	ki.keyspace = name
 }
 
-var invalidKeyspaceNameChars = "/"
+var keyspaceNameRegexp = regexp.MustCompile("^[a-zA-Z][a-zA-Z0-9_-]*$")
 
 // ValidateKeyspaceNames checks if the provided name is a valid name for a
 // keyspace.
 //
 // As of v17, "all invalid characters" is just the forward slash ("/").
 func ValidateKeyspaceName(name string) error {
-	if strings.ContainsAny(name, invalidKeyspaceNameChars) {
-		return vterrors.Errorf(vtrpcpb.Code_INVALID_ARGUMENT, "keyspace name %s contains invalid characters; may not contain any of the following: %+v", name, strings.Split(invalidKeyspaceNameChars, ""))
+	if !keyspaceNameRegexp.MatchString(name) {
+		return vterrors.Errorf(vtrpcpb.Code_INVALID_ARGUMENT, "keyspace name %s contains invalid characters; may only contain alphanumerics, dashes and underscores", name)
 	}
 
 	return nil
diff --git a/go/vt/topo/keyspace_test.go b/go/vt/topo/keyspace_test.go
index 1abf873b8e0..4a96649d593 100644
--- a/go/vt/topo/keyspace_test.go
+++ b/go/vt/topo/keyspace_test.go
@@ -20,6 +20,8 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+
 	topodatapb "vitess.io/vitess/go/vt/proto/topodata"
 )
 
@@ -175,3 +177,49 @@ func TestComputeCellServedFrom(t *testing.T) {
 		t.Fatalf("c2 failed: %v", m)
 	}
 }
+
+func TestValidateKeyspaceName(t *testing.T) {
+	t.Parallel()
+
+	cases := []struct {
+		name  string
+		valid bool
+	}{
+		{
+			name:  "testks",
+			valid: true,
+		},
+		{
+			name:  "alphnum_ks1-with_a_dash",
+			valid: true,
+		},
+		{
+			name:  "no/slashes/allowed",
+			valid: false,
+		},
+		{
+			name:  "wë!rd ch@r@ct3r$",
+			valid: false,
+		},
+		{
+			name:  "0_cant-start_with-a-number",
+			valid: false,
+		},
+	}
+
+	for _, tcase := range cases {
+		tcase := tcase
+		t.Run(tcase.name, func(t *testing.T) {
+			t.Parallel()
+
+			var assertion func(t assert.TestingT, err error, msgAndArgs ...any) bool
+			if tcase.valid {
+				assertion = assert.NoError
+			} else {
+				assertion = assert.Error
+			}
+
+			assertion(t, ValidateKeyspaceName(tcase.name))
+		})
+	}
+}