DockerCLI/vendor/github.com/moby/buildkit/session/auth/authprovider/tokenseed.go

84 lines
1.5 KiB
Go

package authprovider
import (
"crypto/rand"
"encoding/json"
"io/ioutil"
"os"
"path/filepath"
"sync"
"syscall"
"github.com/gofrs/flock"
"github.com/pkg/errors"
)
type tokenSeeds struct {
mu sync.Mutex
dir string
m map[string]seed
}
type seed struct {
Seed []byte
}
func (ts *tokenSeeds) getSeed(host string) ([]byte, error) {
ts.mu.Lock()
defer ts.mu.Unlock()
if err := os.MkdirAll(ts.dir, 0755); err != nil {
return nil, err
}
if ts.m == nil {
ts.m = map[string]seed{}
}
l := flock.New(filepath.Join(ts.dir, ".token_seed.lock"))
if err := l.Lock(); err != nil {
if !errors.Is(err, syscall.EROFS) && errors.Is(err, syscall.EPERM) {
return nil, err
}
} else {
defer l.Unlock()
}
fp := filepath.Join(ts.dir, ".token_seed")
// we include client side randomness to avoid chosen plaintext attack from the daemon side
dt, err := ioutil.ReadFile(fp)
if err != nil {
if !errors.Is(err, os.ErrNotExist) && !errors.Is(err, syscall.ENOTDIR) {
return nil, err
}
} else {
// ignore error in case of crash during previous marshal
_ = json.Unmarshal(dt, &ts.m)
}
v, ok := ts.m[host]
if !ok {
v = seed{Seed: newSeed()}
}
ts.m[host] = v
dt, err = json.MarshalIndent(ts.m, "", " ")
if err != nil {
return nil, err
}
if err := ioutil.WriteFile(fp, dt, 0600); err != nil {
if !errors.Is(err, syscall.EROFS) && !errors.Is(err, syscall.EPERM) {
return nil, err
}
}
return v.Seed, nil
}
func newSeed() []byte {
b := make([]byte, 16)
rand.Read(b)
return b
}