Fixes missing entropy in the uuid package.

math/crypto is seeded with 1 and thus will create predictable UUIDs. Because
amazon-instance and amazon-ebs in the same second when building both targets
the timestamp in front doesn't help either. See #552
This commit is contained in:
Jonas Pfenniger 2013-10-23 10:58:48 +01:00
parent 5b1463f77b
commit fa0a0a895f
1 changed files with 13 additions and 4 deletions

View File

@ -2,17 +2,26 @@ package uuid
import ( import (
"fmt" "fmt"
"math/rand" "crypto/rand"
"encoding/binary"
"time" "time"
) )
func uint32rand() (value uint32) {
err := binary.Read(rand.Reader, binary.LittleEndian, &value)
if err != nil {
panic(err)
}
return
}
// Generates a time ordered UUID. Top 32 bits are a timestamp, // Generates a time ordered UUID. Top 32 bits are a timestamp,
// bottom 96 are random. // bottom 96 are random.
func TimeOrderedUUID() string { func TimeOrderedUUID() string {
unix := uint32(time.Now().UTC().Unix()) unix := uint32(time.Now().UTC().Unix())
rand1 := rand.Uint32() rand1 := uint32rand()
rand2 := rand.Uint32() rand2 := uint32rand()
rand3 := rand.Uint32() rand3 := uint32rand()
return fmt.Sprintf("%08x-%04x-%04x-%04x-%04x%08x", return fmt.Sprintf("%08x-%04x-%04x-%04x-%04x%08x",
unix, unix,
uint16(rand1>>16), uint16(rand1>>16),