X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=passwd.go;h=6da64762ad2dae302dd9e8c6c097bec08e0a46fb;hb=refs%2Fheads%2Fmaster;hp=54da63b3f30252f65e5c1717318b683686a037c1;hpb=7adc7f83eddd37aa372aa10159128b6d16c4320a;p=nsscash%2Fnsscash.git

diff --git a/passwd.go b/passwd.go
index 54da63b..6da6476 100644
--- a/passwd.go
+++ b/passwd.go
@@ -1,6 +1,6 @@
 // Parse /etc/passwd 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"
@@ -53,6 +54,11 @@ func ParsePasswds(r io.Reader) ([]Passwd, 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
@@ -103,6 +109,11 @@ func SerializePasswd(p Passwd) ([]byte, error) {
 	offShell := uint16(data.Len())
 	data.Write([]byte(p.Shell))
 	data.WriteByte(0)
+	// Ensure the offsets can fit the length of this entry
+	if data.Len() > math.MaxUint16 {
+		return nil, fmt.Errorf("passwd too large to serialize: %v, %v",
+			data.Len(), p)
+	}
 	size := uint16(data.Len())
 
 	var res bytes.Buffer // serialized result