openpgp: Check session key size.

  - Fix session key size in test.

2 files changed, 15 insertions, 2 deletions

diff --git a/openpgp/src/message/mod.rs b/openpgp/src/message/mod.rs
index 65b6d34c..094779dd 100644
--- a/openpgp/src/message/mod.rs
+++ b/openpgp/src/message/mod.rs
@@ -1052,10 +1052,11 @@ mod tests {
         // 0: SK-ESK
         // => bad.
         let mut packets : Vec<Packet> = Vec::new();
-        let sk = crate::crypto::SessionKey::new(8);
+        let cipher = SymmetricAlgorithm::AES256;
+        let sk = crate::crypto::SessionKey::new(cipher.key_size().unwrap());
         #[allow(deprecated)]
         packets.push(SKESK4::with_password(
-            SymmetricAlgorithm::AES256,
+            cipher,
             S2K::Simple { hash: HashAlgorithm::SHA256 },
             &sk,
             &"12345678".into()).unwrap().into());
diff --git a/openpgp/src/packet/skesk.rs b/openpgp/src/packet/skesk.rs
index 0b9de42b..9e6d9a2c 100644
--- a/openpgp/src/packet/skesk.rs
+++ b/openpgp/src/packet/skesk.rs
@@ -103,6 +103,12 @@ impl SKESK4 {
     pub fn with_password(algo: SymmetricAlgorithm, s2k: S2K,
                          session_key: &SessionKey, password: &Password)
                          -> Result<SKESK4> {
+        if session_key.len() != algo.key_size()? {
+            return Err(Error::InvalidArgument(format!(
+                "Invalid size of session key, got {} want {}",
+                session_key.len(), algo.key_size()?)).into());
+        }
+
         // Derive key and make a cipher.
         let key = s2k.derive_key(password, algo.key_size()?)?;
         let mut cipher = algo.make_encrypt_cfb(&key[..])?;
@@ -290,6 +296,12 @@ impl SKESK5 {
                          aead: AEADAlgorithm, s2k: S2K,
                          session_key: &SessionKey, password: &Password)
                          -> Result<Self> {
+        if session_key.len() != cipher.key_size()? {
+            return Err(Error::InvalidArgument(format!(
+                "Invalid size of session key, got {} want {}",
+                session_key.len(), cipher.key_size()?)).into());
+        }
+
         // Derive key and make a cipher.
         let key = s2k.derive_key(password, cipher.key_size()?)?;
         let mut iv = vec![0u8; aead.iv_size()?];