X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=group.go;h=4ca213a0edfabc48fd7a95e4280509c4547c9d5c;hb=06dfc130f0f152ef11c3113f7237e822b3e45b5b;hp=214f91438d78740a331c487cbfe5ecab1355718c;hpb=c6b898ea9ab372c58c59658c2acf17ea831d71db;p=nsscash%2Fnsscash.git

diff --git a/group.go b/group.go
index 214f914..4ca213a 100644
--- a/group.go
+++ b/group.go
@@ -26,6 +26,7 @@ import (
 	"sort"
 	"strconv"
 	"strings"
+	"math"
 
 	"github.com/pkg/errors"
 )
@@ -102,7 +103,7 @@ func ParseGroups(r io.Reader) ([]Group, error) {
 	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
@@ -130,6 +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
@@ -158,7 +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 {
@@ -168,7 +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