fix: support oidc group allowlist in oss (#19430)

## Summary

In this pull request we're adding support for OIDC allowed groups in the
OSS version as part of work for
https://github.com/coder/coder/issues/17027.

### Changes

- Restored support for parsing group allow list in OSS code

### Testing

- Added tests for OSS code
- Tested allowed/prohibited group OIDC flows in premium and OSS

coderd/idpsync/group.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"net/http"
 
 	"github.com/golang-jwt/jwt/v4"
 	"github.com/google/uuid"
@@ -71,9 +72,49 @@ func (s AGPLIDPSync) GroupSyncSettings(ctx context.Context, orgID uuid.UUID, db
 	return settings, nil
 }
 
-func (s AGPLIDPSync) ParseGroupClaims(_ context.Context, _ jwt.MapClaims) (GroupParams, *HTTPError) {
+func (s AGPLIDPSync) ParseGroupClaims(_ context.Context, mergedClaims jwt.MapClaims) (GroupParams, *HTTPError) {
+	if s.GroupField != "" && len(s.GroupAllowList) > 0 {
+		groupsRaw, ok := mergedClaims[s.GroupField]
+		if !ok {
+			return GroupParams{}, &HTTPError{
+				Code:             http.StatusForbidden,
+				Msg:              "Not a member of an allowed group",
+				Detail:           "You have no groups in your claims!",
+				RenderStaticPage: true,
+			}
+		}
+		parsedGroups, err := ParseStringSliceClaim(groupsRaw)
+		if err != nil {
+			return GroupParams{}, &HTTPError{
+				Code:             http.StatusBadRequest,
+				Msg:              "Failed read groups from claims for allow list check. Ask an administrator for help.",
+				Detail:           err.Error(),
+				RenderStaticPage: true,
+			}
+		}
+
+		inAllowList := false
+	AllowListCheckLoop:
+		for _, group := range parsedGroups {
+			if _, ok := s.GroupAllowList[group]; ok {
+				inAllowList = true
+				break AllowListCheckLoop
+			}
+		}
+
+		if !inAllowList {
+			return GroupParams{}, &HTTPError{
+				Code:             http.StatusForbidden,
+				Msg:              "Not a member of an allowed group",
+				Detail:           "Ask an administrator to add one of your groups to the allow list.",
+				RenderStaticPage: true,
+			}
+		}
+	}
+
 	return GroupParams{
 		SyncEntitled: s.GroupSyncEntitled(),
+		MergedClaims: mergedClaims,
 	}, nil
 }
 

coderd/idpsync/group_test.go

@@ -44,8 +44,7 @@ func TestParseGroupClaims(t *testing.T) {
 		require.False(t, params.SyncEntitled)
 	})
 
-	// AllowList has no effect in AGPL
-	t.Run("AllowList", func(t *testing.T) {
+	t.Run("NotInAllowList", func(t *testing.T) {
 		t.Parallel()
 
 		s := idpsync.NewAGPLSync(slogtest.Make(t, &slogtest.Options{}),
@@ -59,9 +58,39 @@ func TestParseGroupClaims(t *testing.T) {
 
 		ctx := testutil.Context(t, testutil.WaitMedium)
 
-		params, err := s.ParseGroupClaims(ctx, jwt.MapClaims{})
+		// Invalid group
+		_, err := s.ParseGroupClaims(ctx, jwt.MapClaims{
+			"groups": []string{"bar"},
+		})
+		require.NotNil(t, err)
+		require.Equal(t, 403, err.Code)
+
+		// No groups
+		_, err = s.ParseGroupClaims(ctx, jwt.MapClaims{})
+		require.NotNil(t, err)
+		require.Equal(t, 403, err.Code)
+	})
+
+	t.Run("InAllowList", func(t *testing.T) {
+		t.Parallel()
+
+		s := idpsync.NewAGPLSync(slogtest.Make(t, &slogtest.Options{}),
+			runtimeconfig.NewManager(),
+			idpsync.DeploymentSyncSettings{
+				GroupField: "groups",
+				GroupAllowList: map[string]struct{}{
+					"foo": {},
+				},
+			})
+
+		ctx := testutil.Context(t, testutil.WaitMedium)
+
+		claims := jwt.MapClaims{
+			"groups": []string{"foo", "bar"},
+		}
+		params, err := s.ParseGroupClaims(ctx, claims)
 		require.Nil(t, err)
-		require.False(t, params.SyncEntitled)
+		require.Equal(t, claims, params.MergedClaims)
 	})
 }
 

enterprise/coderd/enidpsync/groups.go

@@ -2,7 +2,6 @@ package enidpsync
 
 import (
 	"context"
-	"net/http"
 
 	"github.com/golang-jwt/jwt/v4"
 
@@ -20,51 +19,12 @@ func (e EnterpriseIDPSync) GroupSyncEntitled() bool {
 // GroupAllowList is implemented here to prevent login by unauthorized users.
 // TODO: GroupAllowList overlaps with the default organization group sync settings.
 func (e EnterpriseIDPSync) ParseGroupClaims(ctx context.Context, mergedClaims jwt.MapClaims) (idpsync.GroupParams, *idpsync.HTTPError) {
-	if !e.GroupSyncEntitled() {
-		return e.AGPLIDPSync.ParseGroupClaims(ctx, mergedClaims)
+	resp, err := e.AGPLIDPSync.ParseGroupClaims(ctx, mergedClaims)
+	if err != nil {
+		return idpsync.GroupParams{}, err
 	}
-
-	if e.GroupField != "" && len(e.GroupAllowList) > 0 {
-		groupsRaw, ok := mergedClaims[e.GroupField]
-		if !ok {
-			return idpsync.GroupParams{}, &idpsync.HTTPError{
-				Code:             http.StatusForbidden,
-				Msg:              "Not a member of an allowed group",
-				Detail:           "You have no groups in your claims!",
-				RenderStaticPage: true,
-			}
-		}
-		parsedGroups, err := idpsync.ParseStringSliceClaim(groupsRaw)
-		if err != nil {
-			return idpsync.GroupParams{}, &idpsync.HTTPError{
-				Code:             http.StatusBadRequest,
-				Msg:              "Failed read groups from claims for allow list check. Ask an administrator for help.",
-				Detail:           err.Error(),
-				RenderStaticPage: true,
-			}
-		}
-
-		inAllowList := false
-	AllowListCheckLoop:
-		for _, group := range parsedGroups {
-			if _, ok := e.GroupAllowList[group]; ok {
-				inAllowList = true
-				break AllowListCheckLoop
-			}
-		}
-
-		if !inAllowList {
-			return idpsync.GroupParams{}, &idpsync.HTTPError{
-				Code:             http.StatusForbidden,
-				Msg:              "Not a member of an allowed group",
-				Detail:           "Ask an administrator to add one of your groups to the allow list.",
-				RenderStaticPage: true,
-			}
-		}
-	}
-
 	return idpsync.GroupParams{
-		SyncEntitled: true,
-		MergedClaims: mergedClaims,
+		SyncEntitled: e.GroupSyncEntitled(),
+		MergedClaims: resp.MergedClaims,
 	}, nil
 }