server: only set default tenant if login successful

Previously, we would always set the default tenant cookie to the
default tenant cluster setting regardless of what tenants the user
logged-in to successfully.

This change ensures that the default tenant selection is only used
when the successful logins include that tenant. Otherwise, we select
the first tenant from the list of successful logins.

Epic: CRDB-12100
Release note: None

pkg/ccl/serverccl/server_controller_test.go

@@ -9,6 +9,7 @@
 package serverccl
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"io"
@@ -19,6 +20,7 @@ import (
 	"time"
 
 	"github.com/cockroachdb/cockroach/pkg/base"
+	"github.com/cockroachdb/cockroach/pkg/roachpb"
 	"github.com/cockroachdb/cockroach/pkg/server"
 	"github.com/cockroachdb/cockroach/pkg/server/serverpb"
 	"github.com/cockroachdb/cockroach/pkg/sql/lexbase"
@@ -183,6 +185,47 @@ VALUES($1, $2, $3, $4, $5)`, id, secret, username, created, expires)
 	require.Equal(t, body.Sessions[0].ApplicationName, "hello system")
 }
 
+// TestServerControllerDefaultHTTPTenant ensures that the default
+// tenant selected in the cookie does not use the default tenant
+// from the cluster setting *unless* the user successfully logged
+// in to that tenant.
+func TestServerControllerDefaultHTTPTenant(t *testing.T) {
+	defer leaktest.AfterTest(t)()
+	defer log.Scope(t).Close(t)
+
+	ctx := context.Background()
+
+	s, _, _ := serverutils.StartServer(t, base.TestServerArgs{DisableDefaultTestTenant: true})
+	defer s.Stopper().Stop(ctx)
+
+	_, sql, err := s.StartSharedProcessTenant(ctx, base.TestSharedProcessTenantArgs{
+		TenantName: "hello",
+		TenantID:   roachpb.MustMakeTenantID(10),
+	})
+	require.NoError(t, err)
+
+	_, err = sql.Exec("CREATE user foo with password 'cockroach'")
+	require.NoError(t, err)
+
+	client, err := s.GetUnauthenticatedHTTPClient()
+	require.NoError(t, err)
+
+	resp, err := client.Post(s.AdminURL()+"/login",
+		"application/json",
+		bytes.NewBuffer([]byte("{\"username\":\"foo\",\"password\":\"cockroach\"})")),
+	)
+	require.NoError(t, err)
+	defer resp.Body.Close()
+
+	tenantCookie := ""
+	for _, c := range resp.Cookies() {
+		if c.Name == server.TenantSelectCookieName {
+			tenantCookie = c.Value
+		}
+	}
+	require.Equal(t, "hello", tenantCookie)
+}
+
 // TestServerControllerBadHTTPCookies tests the controller's proxy
 // layer for correct behavior under scenarios where the client has
 // stale or invalid cookies. This helps ensure that we continue to

pkg/server/server_controller_http.go

@@ -201,9 +201,21 @@ func (c *serverController) attemptLoginToAllTenants() http.Handler {
 			http.SetCookie(w, &cookie)
 			// The tenant cookie needs to be set at some point in order for
 			// the dropdown to have a current selection on first load.
+
+			// We only set the default selection from the cluster setting
+			// if it's one of the valid logins. Otherwise, we just use the
+			// first one in the list.
+			tenantSelection := tenantNameToSetCookieSlice[0].name
+			defaultName := defaultTenantSelect.Get(&c.st.SV)
+			for _, t := range tenantNameToSetCookieSlice {
+				if t.name == defaultName {
+					tenantSelection = t.name
+					break
+				}
+			}
 			cookie = http.Cookie{
 				Name:     TenantSelectCookieName,
-				Value:    defaultTenantSelect.Get(&c.st.SV),
+				Value:    tenantSelection,
 				Path:     "/",
 				HttpOnly: false,
 			}