X-Git-Url: https://ruderich.org/simon/gitweb/?p=nsscash%2Fnsscash.git;a=blobdiff_plain;f=group.go;h=018a0c32716c665c690c78903b6eccdb5435ac54;hp=126ebb0dc349e0127c4ff14f3b61f48cb99cc737;hb=HEAD;hpb=7adc7f83eddd37aa372aa10159128b6d16c4320a

diff --git a/group.go b/group.go
index 126ebb0..018a0c3 100644
--- a/group.go
+++ b/group.go
@@ -1,6 +1,6 @@
 // Parse /etc/group files and serialize them
 
-// Copyright (C) 2019  Simon Ruderich
+// Copyright (C) 2019-2021  Simon Ruderich
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU Affero General Public License as published by
@@ -23,6 +23,7 @@ import (
 	"encoding/binary"
 	"fmt"
 	"io"
+	"math"
 	"sort"
 	"strconv"
 	"strings"
@@ -67,6 +68,11 @@ func ParseGroups(r io.Reader) ([]Group, error) {
 		t, err := s.ReadString('\n')
 		if err != nil {
 			if err == io.EOF {
+				if t != "" {
+					return nil, fmt.Errorf(
+						"no newline in last line: %q",
+						t)
+				}
 				break
 			}
 			return nil, err
@@ -130,6 +136,11 @@ func SerializeGroup(g Group) ([]byte, error) {
 	}
 	// And the group members concatenated as above
 	data.Write(mems.Bytes())
+	// Ensure the offsets can fit the length of this entry
+	if data.Len() > math.MaxUint16 {
+		return nil, fmt.Errorf("group too large to serialize: %v, %v",
+			data.Len(), g)
+	}
 	size := uint16(data.Len())
 
 	var res bytes.Buffer // serialized result
@@ -183,7 +194,7 @@ func SerializeGroups(w io.Writer, grs []Group) error {
 	tmp := make([]byte, 8)
 
 	// Create index "sorted" in input order, used when iterating over all
-	// passwd entries (getgrent_r); keeping the original order makes
+	// group entries (getgrent_r); keeping the original order makes
 	// debugging easier
 	var indexOrig bytes.Buffer
 	for _, g := range grs {