From 248ae9d4ba40975558c928ae0d28fdd78c16d26d Mon Sep 17 00:00:00 2001
From: Toni Spets <toni.spets@iki.fi>
Date: Sun, 29 Oct 2017 17:07:56 +0200
Subject: [PATCH] SymmetricCipher: Add keySize(), don't rely on state for sizes

This additionally makes keySize() and blockSize() work before
setting the key and IV. Required for SSH agent decryption.
---
 src/crypto/SymmetricCipher.cpp       |  5 +++++
 src/crypto/SymmetricCipher.h         |  1 +
 src/crypto/SymmetricCipherBackend.h  |  1 +
 src/crypto/SymmetricCipherGcrypt.cpp | 30 ++++++++++++++++++----------
 src/crypto/SymmetricCipherGcrypt.h   |  2 +-
 5 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/src/crypto/SymmetricCipher.cpp b/src/crypto/SymmetricCipher.cpp
index 98d481969..016103b27 100644
--- a/src/crypto/SymmetricCipher.cpp
+++ b/src/crypto/SymmetricCipher.cpp
@@ -74,6 +74,11 @@ bool SymmetricCipher::reset()
     return m_backend->reset();
 }
 
+int SymmetricCipher::keySize() const
+{
+    return m_backend->keySize();
+}
+
 int SymmetricCipher::blockSize() const
 {
     return m_backend->blockSize();
diff --git a/src/crypto/SymmetricCipher.h b/src/crypto/SymmetricCipher.h
index 4f1d50c12..81e13f385 100644
--- a/src/crypto/SymmetricCipher.h
+++ b/src/crypto/SymmetricCipher.h
@@ -70,6 +70,7 @@ public:
     }
 
     bool reset();
+    int keySize() const;
     int blockSize() const;
     QString errorString() const;
 
diff --git a/src/crypto/SymmetricCipherBackend.h b/src/crypto/SymmetricCipherBackend.h
index 78ec60c60..dd493d2df 100644
--- a/src/crypto/SymmetricCipherBackend.h
+++ b/src/crypto/SymmetricCipherBackend.h
@@ -33,6 +33,7 @@ public:
     Q_REQUIRED_RESULT virtual bool processInPlace(QByteArray& data, quint64 rounds) = 0;
 
     virtual bool reset() = 0;
+    virtual int keySize() const = 0;
     virtual int blockSize() const = 0;
 
     virtual QString errorString() const = 0;
diff --git a/src/crypto/SymmetricCipherGcrypt.cpp b/src/crypto/SymmetricCipherGcrypt.cpp
index c88dbd8c2..ed031c00f 100644
--- a/src/crypto/SymmetricCipherGcrypt.cpp
+++ b/src/crypto/SymmetricCipherGcrypt.cpp
@@ -26,7 +26,6 @@ SymmetricCipherGcrypt::SymmetricCipherGcrypt(SymmetricCipher::Algorithm algo, Sy
     , m_algo(gcryptAlgo(algo))
     , m_mode(gcryptMode(mode))
     , m_direction(direction)
-    , m_blockSize(-1)
 {
 }
 
@@ -95,14 +94,6 @@ bool SymmetricCipherGcrypt::init()
         return false;
     }
 
-    size_t blockSizeT;
-    error = gcry_cipher_algo_info(m_algo, GCRYCTL_GET_BLKLEN, nullptr, &blockSizeT);
-    if (error != 0) {
-        setErrorString(error);
-        return false;
-    }
-
-    m_blockSize = blockSizeT;
     return true;
 }
 
@@ -237,9 +228,28 @@ bool SymmetricCipherGcrypt::reset()
     return true;
 }
 
+int SymmetricCipherGcrypt::keySize() const
+{
+    gcry_error_t error;
+    size_t keySizeT;
+
+    error = gcry_cipher_algo_info(m_algo, GCRYCTL_GET_KEYLEN, nullptr, &keySizeT);
+    if (error != 0)
+        return -1;
+
+    return keySizeT;
+}
+
 int SymmetricCipherGcrypt::blockSize() const
 {
-    return m_blockSize;
+    gcry_error_t error;
+    size_t blockSizeT;
+
+    error = gcry_cipher_algo_info(m_algo, GCRYCTL_GET_BLKLEN, nullptr, &blockSizeT);
+    if (error != 0)
+        return -1;
+
+    return blockSizeT;
 }
 
 QString SymmetricCipherGcrypt::errorString() const
diff --git a/src/crypto/SymmetricCipherGcrypt.h b/src/crypto/SymmetricCipherGcrypt.h
index d3ad8d15b..108bc14e4 100644
--- a/src/crypto/SymmetricCipherGcrypt.h
+++ b/src/crypto/SymmetricCipherGcrypt.h
@@ -39,6 +39,7 @@ public:
     Q_REQUIRED_RESULT bool processInPlace(QByteArray& data, quint64 rounds);
 
     bool reset();
+    int keySize() const;
     int blockSize() const;
 
     QString errorString() const;
@@ -54,7 +55,6 @@ private:
     const SymmetricCipher::Direction m_direction;
     QByteArray m_key;
     QByteArray m_iv;
-    int m_blockSize;
     QString m_errorString;
 };