зеркало из https://github.com/github/smimesign.git
211 строки
6.6 KiB
Go
211 строки
6.6 KiB
Go
package main
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import (
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"crypto"
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"crypto/x509"
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"fmt"
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"os"
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"sync"
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"time"
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"golang.org/x/crypto/openpgp/packet"
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"golang.org/x/crypto/openpgp/s2k"
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)
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// This file implements gnupg's "status protocol". When the --status-fd argument
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// is passed, gpg will output machine-readable status updates to that fd.
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// Details on the "protocol" can be found at https://git.io/vFFKC
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type status string
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const (
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// BEGIN_SIGNING
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// Mark the start of the actual signing process. This may be used as an
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// indication that all requested secret keys are ready for use.
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sBeginSigning status = "BEGING_SIGNING"
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// SIG_CREATED <type> <pk_algo> <hash_algo> <class> <timestamp> <keyfpr>
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// A signature has been created using these parameters.
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// Values for type <type> are:
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// - D :: detached
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// - C :: cleartext
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// - S :: standard
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// (only the first character should be checked)
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//
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// <class> are 2 hex digits with the OpenPGP signature class.
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//
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// Note, that TIMESTAMP may either be a number of seconds since Epoch
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// or an ISO 8601 string which can be detected by the presence of the
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// letter 'T'.
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sSigCreated status = "SIG_CREATED"
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// NEWSIG [<signers_uid>]
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// Is issued right before a signature verification starts. This is
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// useful to define a context for parsing ERROR status messages.
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// arguments are currently defined. If SIGNERS_UID is given and is
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// not "-" this is the percent escape value of the OpenPGP Signer's
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// User ID signature sub-packet.
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sNewSig status = "NEWSIG"
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// GOODSIG <long_keyid_or_fpr> <username>
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// The signature with the keyid is good. For each signature only one
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// of the codes GOODSIG, BADSIG, EXPSIG, EXPKEYSIG, REVKEYSIG or
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// ERRSIG will be emitted. In the past they were used as a marker
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// for a new signature; new code should use the NEWSIG status
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// instead. The username is the primary one encoded in UTF-8 and %XX
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// escaped. The fingerprint may be used instead of the long keyid if
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// it is available. This is the case with CMS and might eventually
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// also be available for OpenPGP.
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sGoodSig status = "GOODSIG"
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// BADSIG <long_keyid_or_fpr> <username>
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// The signature with the keyid has not been verified okay. The username is
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// the primary one encoded in UTF-8 and %XX escaped. The fingerprint may be
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// used instead of the long keyid if it is available. This is the case with
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// CMS and might eventually also be available for OpenPGP.
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sBadSig status = "BADSIG"
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// ERRSIG <keyid> <pkalgo> <hashalgo> <sig_class> <time> <rc>
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//
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// It was not possible to check the signature. This may be caused by a
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// missing public key or an unsupported algorithm. A RC of 4 indicates
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// unknown algorithm, a 9 indicates a missing public key. The other fields
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// give more information about this signature. sig_class is a 2 byte hex-
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// value. The fingerprint may be used instead of the keyid if it is
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// available. This is the case with gpgsm and might eventually also be
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// available for OpenPGP.
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//
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// Note, that TIME may either be the number of seconds since Epoch or an ISO
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// 8601 string. The latter can be detected by the presence of the letter
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// ‘T’.
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sErrSig status = "ERRSIG"
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// TRUST_
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// These are several similar status codes:
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//
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// - TRUST_UNDEFINED <error_token>
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// - TRUST_NEVER <error_token>
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// - TRUST_MARGINAL [0 [<validation_model>]]
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// - TRUST_FULLY [0 [<validation_model>]]
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// - TRUST_ULTIMATE [0 [<validation_model>]]
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//
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// For good signatures one of these status lines are emitted to
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// indicate the validity of the key used to create the signature.
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// The error token values are currently only emitted by gpgsm.
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//
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// VALIDATION_MODEL describes the algorithm used to check the
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// validity of the key. The defaults are the standard Web of Trust
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// model for gpg and the standard X.509 model for gpgsm. The
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// defined values are
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//
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// - pgp :: The standard PGP WoT.
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// - shell :: The standard X.509 model.
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// - chain :: The chain model.
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// - steed :: The STEED model.
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// - tofu :: The TOFU model
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//
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// Note that the term =TRUST_= in the status names is used for
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// historic reasons; we now speak of validity.
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sTrustFully status = "TRUST_FULLY"
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)
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var (
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setupStatus sync.Once
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statusFile *os.File
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)
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func (s status) emitf(format string, args ...interface{}) {
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setupStatus.Do(func() {
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if *statusFdOpt > 0 {
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// TODO: debugging output if this fails
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statusFile = os.NewFile(uintptr(*statusFdOpt), "status")
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}
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})
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if statusFile == nil {
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return
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}
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const prefix = "[GNUPG:] "
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statusFile.WriteString(prefix)
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statusFile.WriteString(string(s))
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fmt.Fprintf(statusFile, " "+format+"\n", args...)
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}
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func (s status) emit() {
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setupStatus.Do(func() {
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if *statusFdOpt > 0 {
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// TODO: debugging output if this fails
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statusFile = os.NewFile(uintptr(*statusFdOpt), "status")
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}
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})
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if statusFile == nil {
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return
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}
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const prefix = "[GNUPG:] "
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statusFile.WriteString(prefix + string(s) + "\n")
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}
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func emitSigCreated(cert *x509.Certificate, isDetached bool) {
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// SIG_CREATED arguments
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var (
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sigType string
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pkAlgo, hashAlgo, sigClass byte
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now int64
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fpr string
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)
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if isDetached {
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sigType = "D"
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} else {
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sigType = "S"
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}
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switch cert.SignatureAlgorithm {
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case x509.SHA1WithRSA, x509.SHA256WithRSA, x509.SHA384WithRSA, x509.SHA512WithRSA:
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pkAlgo = byte(packet.PubKeyAlgoRSA)
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case x509.ECDSAWithSHA1, x509.ECDSAWithSHA256, x509.ECDSAWithSHA384, x509.ECDSAWithSHA512:
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pkAlgo = byte(packet.PubKeyAlgoECDSA)
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}
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switch cert.SignatureAlgorithm {
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case x509.SHA1WithRSA, x509.ECDSAWithSHA1:
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hashAlgo, _ = s2k.HashToHashId(crypto.SHA1)
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case x509.SHA256WithRSA, x509.ECDSAWithSHA256:
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hashAlgo, _ = s2k.HashToHashId(crypto.SHA256)
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case x509.SHA384WithRSA, x509.ECDSAWithSHA384:
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hashAlgo, _ = s2k.HashToHashId(crypto.SHA384)
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case x509.SHA512WithRSA, x509.ECDSAWithSHA512:
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hashAlgo, _ = s2k.HashToHashId(crypto.SHA512)
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}
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// gpgsm seems to always use 0x00
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sigClass = 0
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now = time.Now().Unix()
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fpr = certHexFingerprint(cert)
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sSigCreated.emitf("%s %d %d %02x %d %s", sigType, pkAlgo, hashAlgo, sigClass, now, fpr)
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}
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func emitGoodSig(chains [][][]*x509.Certificate) {
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cert := chains[0][0][0]
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subj := cert.Subject.ToRDNSequence().String()
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fpr := certHexFingerprint(cert)
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sGoodSig.emitf("%s %s", fpr, subj)
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}
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func emitBadSig(chains [][][]*x509.Certificate) {
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cert := chains[0][0][0]
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subj := cert.Subject.ToRDNSequence().String
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fpr := certHexFingerprint(cert)
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sBadSig.emitf("%s %s", fpr, subj)
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}
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func emitTrustFully() {
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sTrustFully.emitf("0 shell")
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}
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