X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=group.go;h=4ca213a0edfabc48fd7a95e4280509c4547c9d5c;hb=06dfc130f0f152ef11c3113f7237e822b3e45b5b;hp=4513758df41c4a8d22eb32f8fac5653e773ca3dd;hpb=1d028880cfb17a7c8a9e3b1f54cf1e980baca63d;p=nsscash%2Fnsscash.git

diff --git a/group.go b/group.go
index 4513758..4ca213a 100644
--- a/group.go
+++ b/group.go
@@ -26,6 +26,7 @@ import (
 	"sort"
 	"strconv"
 	"strings"
+	"math"
 
 	"github.com/pkg/errors"
 )
@@ -45,7 +46,7 @@ type GroupKey struct {
 	Name    string
 	Passwd  string
 	Gid     uint64
-	Members string
+	Members string // "," separated
 }
 
 func toKey(g Group) GroupKey {
@@ -58,13 +59,19 @@ func toKey(g Group) GroupKey {
 }
 
 // ParseGroups parses a file in the format of /etc/group and returns all
-// entries as Group structs.
+// entries as slice of Group structs.
 func ParseGroups(r io.Reader) ([]Group, error) {
 	var res []Group
 
-	s := bufio.NewScanner(r)
-	for s.Scan() {
-		t := s.Text()
+	s := bufio.NewReader(r)
+	for {
+		t, err := s.ReadString('\n')
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return nil, err
+		}
 
 		x := strings.Split(t, ":")
 		if len(x) != 4 {
@@ -76,6 +83,9 @@ func ParseGroups(r io.Reader) ([]Group, error) {
 			return nil, errors.Wrapf(err, "invalid gid in line %q", t)
 		}
 
+		// ReadString() contains the delimiter
+		x[3] = strings.TrimSuffix(x[3], "\n")
+
 		var members []string
 		// No members must result in empty slice, not slice with the
 		// empty string
@@ -89,15 +99,11 @@ func ParseGroups(r io.Reader) ([]Group, error) {
 			Members: members,
 		})
 	}
-	err := s.Err()
-	if err != nil {
-		return nil, err
-	}
 
 	return res, nil
 }
 
-func SerializeGroup(g Group) []byte {
+func SerializeGroup(g Group) ([]byte, error) {
 	le := binary.LittleEndian
 
 	// Concatenate all (NUL-terminated) strings and store the offsets
@@ -125,6 +131,11 @@ func SerializeGroup(g Group) []byte {
 	}
 	// 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
@@ -153,7 +164,7 @@ func SerializeGroup(g Group) []byte {
 	// struct are 8 byte aligned
 	alignBufferTo(&res, 8)
 
-	return res.Bytes()
+	return res.Bytes(), nil
 }
 
 func SerializeGroups(w io.Writer, grs []Group) error {
@@ -163,7 +174,11 @@ func SerializeGroups(w io.Writer, grs []Group) error {
 	for _, g := range grs {
 		// TODO: warn about duplicate entries
 		offsets[toKey(g)] = uint64(data.Len())
-		data.Write(SerializeGroup(g))
+		x, err := SerializeGroup(g)
+		if err != nil {
+			return err
+		}
+		data.Write(x)
 	}
 
 	// Copy to prevent sorting from modifying the argument