openpgp: Allow V3 signatures in messages

Previously, only V4 signatures were allowed in PGP messages,
and attempts to digest a message with a V3 signature would
yield an `errors.StructuralError("LiteralData not followed by Signature")`.

This patch fixes this shortcoming, by trying to consume either
signature type and verifying accordingly.

Change-Id: I27c8ea781b75b0f7dfc42c01e7de40f3323e9579
Reviewed-on: https://go-review.googlesource.com/14794
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
This commit is contained in:
Maxwell Krohn
2016-04-06 04:37:51 +00:00
committed by Brad Fitzpatrick
parent 9e7f5dc375
commit b8a0f4bb40
2 changed files with 86 additions and 5 deletions
+8 -5
View File
@@ -56,8 +56,9 @@ type MessageDetails struct {
// been consumed. Once EOF has been seen, the following fields are
// valid. (An authentication code failure is reported as a
// SignatureError error when reading from UnverifiedBody.)
SignatureError error // nil if the signature is good.
Signature *packet.Signature // the signature packet itself.
SignatureError error // nil if the signature is good.
Signature *packet.Signature // the signature packet itself, if v4 (default)
SignatureV3 *packet.SignatureV3 // the signature packet if it is a v2 or v3 signature
decrypted io.ReadCloser
}
@@ -334,13 +335,15 @@ func (scr *signatureCheckReader) Read(buf []byte) (n int, err error) {
}
var ok bool
if scr.md.Signature, ok = p.(*packet.Signature); !ok {
if scr.md.Signature, ok = p.(*packet.Signature); ok {
scr.md.SignatureError = scr.md.SignedBy.PublicKey.VerifySignature(scr.h, scr.md.Signature)
} else if scr.md.SignatureV3, ok = p.(*packet.SignatureV3); ok {
scr.md.SignatureError = scr.md.SignedBy.PublicKey.VerifySignatureV3(scr.h, scr.md.SignatureV3)
} else {
scr.md.SignatureError = errors.StructuralError("LiteralData not followed by Signature")
return
}
scr.md.SignatureError = scr.md.SignedBy.PublicKey.VerifySignature(scr.h, scr.md.Signature)
// The SymmetricallyEncrypted packet, if any, might have an
// unsigned hash of its own. In order to check this we need to
// close that Reader.