From 258394678f759dee27b8be2dd13f2a317051fc51 Mon Sep 17 00:00:00 2001
From: "Neal H. Walfield" <neal@sequoia-pgp.org>
Date: Sat, 23 Nov 2024 10:55:18 +0100
Subject: [PATCH] Don't use revoked certificates for encryption.

  - Change `sq encrypt` to not use revoked certificates.
---
 src/commands/encrypt.rs         | 10 ++++++
 tests/integration/sq_encrypt.rs | 55 ++++++++++++++++++++++++++++++++-
 2 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/src/commands/encrypt.rs b/src/commands/encrypt.rs
index 0c412b7a..92a97988 100644
--- a/src/commands/encrypt.rs
+++ b/src/commands/encrypt.rs
@@ -21,6 +21,7 @@ use openpgp::serialize::stream::Signer;
 use openpgp::serialize::stream::padding::Padder;
 use openpgp::types::CompressionAlgorithm;
 use openpgp::types::KeyFlags;
+use openpgp::types::RevocationStatus;
 use openpgp::types::SignatureType;
 
 use crate::cli;
@@ -136,6 +137,15 @@ pub fn encrypt<'a, 'b: 'a>(
     // Build a vector of recipients to hand to Encryptor.
     let mut recipient_subkeys: Vec<Recipient> = Vec::new();
     for cert in recipients.iter() {
+        if let RevocationStatus::Revoked(_)
+            = cert.revocation_status(policy, time)
+        {
+            return Err(anyhow::anyhow!(
+                "Can't encrypt to {}, {}: it is revoked",
+                cert.fingerprint(),
+                sq.best_userid(&cert, true)));
+        }
+
         let mut count = 0;
         for key in cert.keys().with_policy(policy, time).alive().revoked(false)
             .key_flags(&mode).supported().map(|ka| ka.key())
diff --git a/tests/integration/sq_encrypt.rs b/tests/integration/sq_encrypt.rs
index 3119821b..1c9ff044 100644
--- a/tests/integration/sq_encrypt.rs
+++ b/tests/integration/sq_encrypt.rs
@@ -681,7 +681,7 @@ fn sq_encrypt_expired() -> Result<()>
 // Try encrypting to a certificate with a revoked subkey.  Make sure
 // it fails.
 #[test]
-fn sq_encrypt_revoked() -> Result<()>
+fn sq_encrypt_revoked_subkey() -> Result<()>
 {
     let mut sq = Sq::new();
 
@@ -735,3 +735,56 @@ fn sq_encrypt_revoked() -> Result<()>
 
     Ok(())
 }
+
+// Try encrypting to a revoked certificate.  Make sure it fails.
+#[test]
+fn sq_encrypt_revoked() -> Result<()>
+{
+    let mut sq = Sq::new();
+
+    // Generate the keys.  Alice has an encryption capable subkey, but
+    // Bob doesn't.
+    let (alice, alice_pgp, _alice_rev) = sq.key_generate(
+        &[],
+        &["<alice@example.org>"]);
+    sq.key_import(alice_pgp);
+
+    let alice_enc = alice.keys().with_policy(STANDARD_POLICY, sq.now())
+        .for_storage_encryption()
+        .next()
+        .expect("have a storage encryption-capable subkey")
+        .fingerprint();
+
+    let (bob, bob_pgp, _bob_rev) = sq.key_generate(
+        &[],
+        &["<bob@example.org>"]);
+    sq.key_import(&bob_pgp);
+
+    sq.tick(1);
+
+    // Revoke.
+    let bob = sq.key_revoke(
+        bob.key_handle(), None,
+        "retired", "retired this key", None, &[], None);
+
+    // Two days pass...
+    sq.tick(2 * 24 * 60 * 60);
+
+    for (i, (recipients, result)) in [
+        (&[ &alice ][..], &[ &alice_enc ][..]),
+        (&[ &bob ], &[]),
+        (&[ &alice, &bob ], &[]),
+    ].into_iter().enumerate() {
+        eprintln!("Test #{}", i + 1);
+
+        let recipients = recipients.iter().map(|r| r.fingerprint())
+            .collect::<Vec<Fingerprint>>();
+        let recipients = recipients.iter()
+            .collect::<Vec<&Fingerprint>>();
+
+        try_encrypt(&sq, &[], result, &recipients, &[], &[]);
+    }
+
+    Ok(())
+}
+