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tailscale/tempfork/x509/cert_pool.go

228 lines
6.2 KiB
Go

// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package x509
import (
"crypto/sha256"
"encoding/pem"
"errors"
"runtime"
"sync"
)
type sum224 [sha256.Size224]byte
// CertPool is a set of certificates.
type CertPool struct {
bySubjectKeyId map[string][]int // cert.SubjectKeyId => getCert index(es)
byName map[string][]int // cert.RawSubject => getCert index(es)
// haveSum maps from sum224(cert.Raw) to true. It's used only
// for AddCert duplicate detection, to avoid CertPool.contains
// calls in the AddCert path (because the contains method can
// call getCert and otherwise negate savings from lazy getCert
// funcs).
haveSum map[sum224]bool
// getCert contains funcs that return the certificates.
getCert []func() (*Certificate, error)
// rawSubjects is each cert's RawSubject field.
// Its indexes correspond to the getCert indexes.
rawSubjects [][]byte
}
// NewCertPool returns a new, empty CertPool.
func NewCertPool() *CertPool {
return &CertPool{
bySubjectKeyId: make(map[string][]int),
byName: make(map[string][]int),
haveSum: make(map[sum224]bool),
}
}
// len returns the number of certs in the set.
// A nil set is a valid empty set.
func (s *CertPool) len() int {
if s == nil {
return 0
}
return len(s.getCert)
}
// cert returns cert index n in s.
func (s *CertPool) cert(n int) (*Certificate, error) {
return s.getCert[n]()
}
func (s *CertPool) copy() *CertPool {
p := &CertPool{
bySubjectKeyId: make(map[string][]int, len(s.bySubjectKeyId)),
byName: make(map[string][]int, len(s.byName)),
haveSum: make(map[sum224]bool, len(s.haveSum)),
getCert: make([]func() (*Certificate, error), len(s.getCert)),
rawSubjects: make([][]byte, len(s.rawSubjects)),
}
for k, v := range s.bySubjectKeyId {
indexes := make([]int, len(v))
copy(indexes, v)
p.bySubjectKeyId[k] = indexes
}
for k, v := range s.byName {
indexes := make([]int, len(v))
copy(indexes, v)
p.byName[k] = indexes
}
for k := range s.haveSum {
p.haveSum[k] = true
}
copy(p.getCert, s.getCert)
copy(p.rawSubjects, s.rawSubjects)
return p
}
// SystemCertPool returns a copy of the system cert pool.
//
// Any mutations to the returned pool are not written to disk and do
// not affect any other pool returned by SystemCertPool.
//
// New changes in the system cert pool might not be reflected
// in subsequent calls.
func SystemCertPool() (*CertPool, error) {
if runtime.GOOS == "windows" {
// Issue 16736, 18609:
return nil, errors.New("crypto/x509: system root pool is not available on Windows")
}
if sysRoots := systemRootsPool(); sysRoots != nil {
return sysRoots.copy(), nil
}
return loadSystemRoots()
}
// findPotentialParents returns the indexes of certificates in s which might
// have signed cert. The caller must not modify the returned slice.
func (s *CertPool) findPotentialParents(cert *Certificate) []int {
if s == nil {
return nil
}
var candidates []int
if len(cert.AuthorityKeyId) > 0 {
candidates = s.bySubjectKeyId[string(cert.AuthorityKeyId)]
}
if len(candidates) == 0 {
candidates = s.byName[string(cert.RawIssuer)]
}
return candidates
}
func (s *CertPool) contains(cert *Certificate) (bool, error) {
if s == nil {
return false, nil
}
candidates := s.byName[string(cert.RawSubject)]
for _, i := range candidates {
c, err := s.cert(i)
if err != nil {
return false, err
}
if c.Equal(cert) {
return true, nil
}
}
return false, nil
}
// AddCert adds a certificate to a pool.
func (s *CertPool) AddCert(cert *Certificate) {
if cert == nil {
panic("adding nil Certificate to CertPool")
}
s.AddCertFunc(sha256.Sum224(cert.Raw), string(cert.RawSubject), string(cert.SubjectKeyId), func() (*Certificate, error) {
return cert, nil
})
}
// AddCertFunc adds metadata about a certificate to a pool, along with
// a func to fetch that certificate later when needed.
//
// The rawSubject is Certificate.RawSubject and must be non-empty.
// The subjectKeyID is Certificate.SubjectKeyId and may be empty.
// The getCert func may be called 0 or more times.
func (s *CertPool) AddCertFunc(rawSum224 sum224, rawSubject, subjectKeyID string, getCert func() (*Certificate, error)) {
// Check that the certificate isn't being added twice.
if s.haveSum[rawSum224] {
return
}
s.haveSum[rawSum224] = true
s.addCertFuncNotDup(rawSubject, subjectKeyID, getCert)
}
func (s *CertPool) addCertFuncNotDup(rawSubject, subjectKeyID string, getCert func() (*Certificate, error)) {
if getCert == nil {
panic("getCert can't be nil")
}
n := len(s.getCert)
s.getCert = append(s.getCert, getCert)
if subjectKeyID != "" {
s.bySubjectKeyId[subjectKeyID] = append(s.bySubjectKeyId[subjectKeyID], n)
}
s.byName[rawSubject] = append(s.byName[rawSubject], n)
s.rawSubjects = append(s.rawSubjects, []byte(rawSubject))
}
// AppendCertsFromPEM attempts to parse a series of PEM encoded certificates.
// It appends any certificates found to s and reports whether any certificates
// were successfully parsed.
//
// On many Linux systems, /etc/ssl/cert.pem will contain the system wide set
// of root CAs in a format suitable for this function.
func (s *CertPool) AppendCertsFromPEM(pemCerts []byte) (ok bool) {
for len(pemCerts) > 0 {
var block *pem.Block
block, pemCerts = pem.Decode(pemCerts)
if block == nil {
break
}
if block.Type != "CERTIFICATE" || len(block.Headers) != 0 {
continue
}
certBytes := block.Bytes
cert, err := ParseCertificate(certBytes)
if err != nil {
continue
}
var lazyCert struct {
sync.Once
v *Certificate
}
s.AddCertFunc(sha256.Sum224(cert.Raw), string(cert.RawSubject), string(cert.SubjectKeyId), func() (*Certificate, error) {
lazyCert.Do(func() {
// This can't fail, as the same bytes already parsed above.
lazyCert.v, _ = ParseCertificate(certBytes)
certBytes = nil
})
return lazyCert.v, nil
})
ok = true
}
return ok
}
// Subjects returns a list of the DER-encoded subjects of
// all of the certificates in the pool.
func (s *CertPool) Subjects() [][]byte {
res := make([][]byte, s.len())
for i, s := range s.rawSubjects {
res[i] = s
}
return res
}