openpgp: Allow trust packets in TPKs

  - Change the KeyringValidator to allow trust packets anywhere a
    signature packet is allowed.

  - This is needed to parse GnuPG Keyrings.

3 files changed, 14 insertions, 1 deletions

diff --git a/openpgp/src/tpk/grammar.lalrpop b/openpgp/src/tpk/grammar.lalrpop
index 92ee318b..374fd242 100644
--- a/openpgp/src/tpk/grammar.lalrpop
+++ b/openpgp/src/tpk/grammar.lalrpop
@@ -116,7 +116,11 @@ OptionalSignatures: Option<Vec<Signature>> = {
             Token::Signature(None) => return None,
             tok => unreachable!("Expected signature token, got {:?}", tok),
         }
-    }
+    },
+
+    // A trust packet can go whereever a signature can go, but they
+    // are ignored.
+    <OptionalSignatures> TRUST,
 }
 
 OptionalComponents: Option<Vec<Component>> = {
@@ -270,6 +274,7 @@ extern {
         USERID => lexer::Token::UserID(_),
         USER_ATTRIBUTE => lexer::Token::UserAttribute(_),
         SIGNATURE => lexer::Token::Signature(_),
+        TRUST => lexer::Token::Trust(_),
         UNKNOWN => lexer::Token::Unknown(_, _),
     }
 }
diff --git a/openpgp/src/tpk/lexer.rs b/openpgp/src/tpk/lexer.rs
index 9bae3b47..50e2f547 100644
--- a/openpgp/src/tpk/lexer.rs
+++ b/openpgp/src/tpk/lexer.rs
@@ -36,6 +36,9 @@ pub enum Token {
     /// A `Signature` packet.
     Signature(Option<Packet>),
 
+    /// A `Trust` packet
+    Trust(Option<Packet>),
+
     /// An `Unknown` packet.
     Unknown(Tag, Option<Packet>),
 }
@@ -62,6 +65,7 @@ impl<'a> From<&'a Token> for Tag {
             &Token::UserID(_) => Tag::UserID,
             &Token::UserAttribute(_) => Tag::UserAttribute,
             &Token::Signature(_) => Tag::Signature,
+            &Token::Trust(_) => Tag::Trust,
             &Token::Unknown(tag, _) => tag,
         }
     }
@@ -83,6 +87,7 @@ impl From<Token> for Option<Packet> {
             Token::UserID(p @ Some(_)) => p,
             Token::UserAttribute(p @ Some(_)) => p,
             Token::Signature(p @ Some(_)) => p,
+            Token::Trust(p @ Some(_)) => p,
             Token::Unknown(_, p @ Some(_)) => p,
 
             Token::PublicKey(None)
@@ -92,6 +97,7 @@ impl From<Token> for Option<Packet> {
             | Token::UserID(None)
             | Token::UserAttribute(None)
             | Token::Signature(None)
+            | Token::Trust(None)
             | Token::Unknown(_, None)
                 => None,
         }
@@ -108,6 +114,7 @@ impl From<Packet> for Option<Token> {
             p @ Packet::UserID(_) => Some(Token::UserID(Some(p))),
             p @ Packet::UserAttribute(_) => Some(Token::UserAttribute(Some(p))),
             p @ Packet::Signature(_) => Some(Token::Signature(Some(p))),
+            p @ Packet::Trust(_) => Some(Token::Trust(Some(p))),
             p @ Packet::Unknown(_) => Some(Token::Unknown(p.tag(), Some(p))),
             _ => None,
         }
diff --git a/openpgp/src/tpk/mod.rs b/openpgp/src/tpk/mod.rs
index 0b8e7c3e..c00d6775 100644
--- a/openpgp/src/tpk/mod.rs
+++ b/openpgp/src/tpk/mod.rs
@@ -248,6 +248,7 @@ impl KeyringValidator {
             Tag::UserID => Token::UserID(None),
             Tag::UserAttribute => Token::UserAttribute(None),
             Tag::Signature => Token::Signature(None),
+            Tag::Trust => Token::Trust(None),
             _ => {
                 // Unknown token.
                 self.error = Some(TPKParserError::OpenPGP(