.github: update upstream actions to latest version

[nsscash/nsscash.git] / passwd.go

diff --git a/passwd.go b/passwd.go
index 54da63b3f30252f65e5c1717318b683686a037c1..6da64762ad2dae302dd9e8c6c097bec08e0a46fb 100644 (file)
--- 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