openpgp: Return Result from Signature::signature_alive.

  - See #371.

4 files changed, 34 insertions, 21 deletions

diff --git a/openpgp/src/cert/mod.rs b/openpgp/src/cert/mod.rs
index 0fb5d988..efe65cf4 100644
--- a/openpgp/src/cert/mod.rs
+++ b/openpgp/src/cert/mod.rs
@@ -225,7 +225,7 @@ impl<C> ComponentBinding<C> {
             };
 
         self.self_signatures[i..].iter().filter(|s| {
-            s.signature_alive(t, time::Duration::new(0, 0))
+            s.signature_alive(t, time::Duration::new(0, 0)).is_ok()
         }).nth(0)
     }
 
@@ -292,7 +292,8 @@ impl<C> ComponentBinding<C> {
            selfsig_creation_time,
            t);
         if let Some(selfsig) = selfsig {
-            assert!(selfsig.signature_alive(t, time::Duration::new(0, 0)));
+            assert!(
+                selfsig.signature_alive(t, time::Duration::new(0, 0)).is_ok());
         }
 
         macro_rules! check {
@@ -322,7 +323,10 @@ impl<C> ComponentBinding<C> {
                            rev.signature_creation_time()
                                .unwrap_or_else(time_zero));
                         None
-                    } else if !rev.signature_alive(t, time::Duration::new(0, 0)) {
+                    } else if
+                        ! rev.signature_alive(t, time::Duration::new(0, 0))
+                          .is_ok()
+                    {
                         t!("  ignoring revocation that is not alive ({:?} - {:?})",
                            rev.signature_creation_time()
                                .unwrap_or_else(time_zero),
@@ -891,7 +895,7 @@ impl Cert {
                 // No binding signature at time `t` => not alive.
                 let selfsig = b.binding_signature(t)?;
 
-                if !selfsig.signature_alive(t, time::Duration::new(0, 0)) {
+                if !selfsig.signature_alive(t, time::Duration::new(0, 0)).is_ok() {
                     return None;
                 }
 
diff --git a/openpgp/src/packet/signature/subpacket.rs b/openpgp/src/packet/signature/subpacket.rs
index e732d17e..e125348b 100644
--- a/openpgp/src/packet/signature/subpacket.rs
+++ b/openpgp/src/packet/signature/subpacket.rs
@@ -2162,7 +2162,7 @@ impl SubpacketAreas {
     ///
     ///  [Section 5.2.3.4 of RFC 4880]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4
     pub fn signature_alive<T, U>(&self, time: T, clock_skew_tolerance: U)
-        -> bool
+        -> Result<()>
         where T: Into<Option<time::SystemTime>>,
               U: Into<Option<time::Duration>>
     {
@@ -2180,13 +2180,19 @@ impl SubpacketAreas {
                     (time, tolerance)
             };
 
-        if let Some(creation_time) = self.signature_creation_time() {
+        match (self.signature_creation_time(), self.signature_expiration_time())
+        {
+            (None, _) =>
+                Err(Error::MalformedPacket("no signature creation time".into())
+                    .into()),
+            (Some(c), Some(e)) if e.as_secs() > 0 && (c + e) < time =>
+                Err(Error::Expired(c + e).into()),
             // Be careful to avoid underflow.
-            cmp::max(creation_time, time::UNIX_EPOCH + tolerance)
-                - tolerance <= time
-                && ! self.signature_expired(time)
-        } else {
-            false
+            (Some(c), _) if cmp::max(c, time::UNIX_EPOCH + tolerance)
+                - tolerance > time =>
+                Err(Error::NotYetLive(cmp::max(c, time::UNIX_EPOCH + tolerance)
+                                      - tolerance).into()),
+            _ => Ok(()),
         }
     }
 
@@ -2755,10 +2761,10 @@ fn accessors() {
     assert!(!sig_.signature_expired(now));
     assert!(sig_.signature_expired(now + ten_minutes));
 
-    assert!(sig_.signature_alive(None, zero_s));
-    assert!(sig_.signature_alive(now, zero_s));
-    assert!(!sig_.signature_alive(now - five_minutes, zero_s));
-    assert!(!sig_.signature_alive(now + ten_minutes, zero_s));
+    assert!(sig_.signature_alive(None, zero_s).is_ok());
+    assert!(sig_.signature_alive(now, zero_s).is_ok());
+    assert!(!sig_.signature_alive(now - five_minutes, zero_s).is_ok());
+    assert!(!sig_.signature_alive(now + ten_minutes, zero_s).is_ok());
 
     sig = sig.set_signature_expiration_time(None).unwrap();
     let sig_ =
@@ -2768,10 +2774,10 @@ fn accessors() {
     assert!(!sig_.signature_expired(now));
     assert!(!sig_.signature_expired(now + ten_minutes));
 
-    assert!(sig_.signature_alive(None, zero_s));
-    assert!(sig_.signature_alive(now, zero_s));
-    assert!(!sig_.signature_alive(now - five_minutes, zero_s));
-    assert!(sig_.signature_alive(now + ten_minutes, zero_s));
+    assert!(sig_.signature_alive(None, zero_s).is_ok());
+    assert!(sig_.signature_alive(now, zero_s).is_ok());
+    assert!(!sig_.signature_alive(now - five_minutes, zero_s).is_ok());
+    assert!(sig_.signature_alive(now + ten_minutes, zero_s).is_ok());
 
     sig = sig.set_exportable_certification(true).unwrap();
     let sig_ =
diff --git a/openpgp/src/parse/stream.rs b/openpgp/src/parse/stream.rs
index 272fc78f..ed8444ef 100644
--- a/openpgp/src/parse/stream.rs
+++ b/openpgp/src/parse/stream.rs
@@ -568,7 +568,7 @@ impl<'a, H: VerificationHelper> Verifier<'a, H> {
             if let Some(sig) = sig {
                 sig.key_flags().for_signing()
                 // Check expiry.
-                    && sig.signature_alive(time, tolerance)
+                    && sig.signature_alive(time, tolerance).is_ok()
                     && sig.key_alive(key, time)
             } else {
                 false
@@ -704,6 +704,7 @@ impl<'a, H: VerificationHelper> Verifier<'a, H> {
                                     if sig.verify(key).unwrap_or(false) {
                                         if sig.signature_alive(
                                             self.time, self.clock_skew_tolerance)
+                                            .is_ok()
                                         {
                                             VerificationResult::GoodChecksum {
                                                 sig: sig.clone(),
@@ -1440,6 +1441,7 @@ impl<'a, H: VerificationHelper + DecryptionHelper> Decryptor<'a, H> {
                                 sig.key_flags().for_signing()
                                 // Check expiry.
                                     && sig.signature_alive(time, tolerance)
+                                       .is_ok()
                                     && sig.key_alive(key, time)
                             } else {
                                 false
@@ -1595,6 +1597,7 @@ impl<'a, H: VerificationHelper + DecryptionHelper> Decryptor<'a, H> {
                                     if sig.verify(key).unwrap_or(false) &&
                                         sig.signature_alive(
                                             self.time, self.clock_skew_tolerance)
+                                        .is_ok()
                                     {
                                         // Check intended recipients.
                                         if let Some(identity) =
diff --git a/openpgp/src/serialize/cert_armored.rs b/openpgp/src/serialize/cert_armored.rs
index 35171b54..480c232b 100644
--- a/openpgp/src/serialize/cert_armored.rs
+++ b/openpgp/src/serialize/cert_armored.rs
@@ -40,7 +40,7 @@ impl Cert {
             // Ignore userids not "alive".
             }).filter_map(|uidb| {
                 if uidb.binding_signature(None)?
-                    .signature_alive(None, None)
+                    .signature_alive(None, None).is_ok()
                 {
                     Some(uidb)
                 } else {