QCryptographicHash: re-add support for Keccak hashing

88a8feeacb fixed QCryptographicHash's
implementation of SHA-3 -- before, QCryptographicHash was
calculating Keccak, not SHA-3. The change however breaks downstreams
that were relying on the "wrong" values calculated by earlier
versions of Qt. To restore compatibility with such calculations,
add the support for Keccak back, as deprecated and to-be-removed
in Qt 6.

[ChangeLog][QtCore][QCryptographicHash] In order to preserve
compatibility with earlier versions of Qt, QCryptographicHash is
now able to calculate Keccak message digests.

Task-number: QTBUG-59770
Change-Id: I740684cb3d0774292fa837a06b444c73fb4eed52
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/tools/qcryptographichash.cpp

@@ -181,13 +181,18 @@ public:
 #endif
     };
 #ifndef QT_CRYPTOGRAPHICHASH_ONLY_SHA1
-    void sha3Finish(int bitCount);
+    enum class Sha3Variant
+    {
+        Sha3,
+        Keccak
+    };
+    void sha3Finish(int bitCount, Sha3Variant sha3Variant);
 #endif
     QByteArray result;
 };
 
 #ifndef QT_CRYPTOGRAPHICHASH_ONLY_SHA1
-void QCryptographicHashPrivate::sha3Finish(int bitCount)
+void QCryptographicHashPrivate::sha3Finish(int bitCount, Sha3Variant sha3Variant)
 {
     /*
         FIPS 202 §6.1 defines SHA-3 in terms of calculating the Keccak function
@@ -214,7 +219,15 @@ void QCryptographicHashPrivate::sha3Finish(int bitCount)
     result.resize(bitCount / 8);
 
     SHA3Context copy = sha3Context;
-    sha3Update(&copy, reinterpret_cast<const BitSequence *>(&sha3FinalSuffix), 2);
+
+    switch (sha3Variant) {
+    case Sha3Variant::Sha3:
+        sha3Update(&copy, reinterpret_cast<const BitSequence *>(&sha3FinalSuffix), 2);
+        break;
+    case Sha3Variant::Keccak:
+        break;
+    }
+
     sha3Final(&copy, reinterpret_cast<BitSequence *>(result.data()));
 }
 #endif
@@ -239,6 +252,10 @@ void QCryptographicHashPrivate::sha3Finish(int bitCount)
 /*!
   \enum QCryptographicHash::Algorithm
 
+  \note In Qt versions before 5.9, when asked to generate a SHA3 hash sum,
+  QCryptographicHash actually calculated Keccak. If you need compatibility with
+  SHA-3 hashes produced by those versions of Qt, use the \c{Keccak_} enumerators.
+
   \value Md4 Generate an MD4 hash sum
   \value Md5 Generate an MD5 hash sum
   \value Sha1 Generate an SHA-1 hash sum
@@ -250,6 +267,10 @@ void QCryptographicHashPrivate::sha3Finish(int bitCount)
   \value Sha3_256 Generate an SHA3-256 hash sum. Introduced in Qt 5.1
   \value Sha3_384 Generate an SHA3-384 hash sum. Introduced in Qt 5.1
   \value Sha3_512 Generate an SHA3-512 hash sum. Introduced in Qt 5.1
+  \value Keccak_224 \deprecated Generate a Keccak-224 hash sum. Introduced in Qt 5.10
+  \value Keccak_256 \deprecated Generate a Keccak-256 hash sum. Introduced in Qt 5.10
+  \value Keccak_384 \deprecated Generate a Keccak-384 hash sum. Introduced in Qt 5.10
+  \value Keccak_512 \deprecated Generate a Keccak-512 hash sum. Introduced in Qt 5.10
 */
 
 /*!
@@ -304,15 +325,19 @@ void QCryptographicHash::reset()
         SHA512Reset(&d->sha512Context);
         break;
     case Sha3_224:
+    case Keccak_224:
         sha3Init(&d->sha3Context, 224);
         break;
     case Sha3_256:
+    case Keccak_256:
         sha3Init(&d->sha3Context, 256);
         break;
     case Sha3_384:
+    case Keccak_384:
         sha3Init(&d->sha3Context, 384);
         break;
     case Sha3_512:
+    case Keccak_512:
         sha3Init(&d->sha3Context, 512);
         break;
 #endif
@@ -355,15 +380,19 @@ void QCryptographicHash::addData(const char *data, int length)
         SHA512Input(&d->sha512Context, reinterpret_cast<const unsigned char *>(data), length);
         break;
     case Sha3_224:
+    case Keccak_224:
         sha3Update(&d->sha3Context, reinterpret_cast<const BitSequence *>(data), length*8);
         break;
     case Sha3_256:
+    case Keccak_256:
         sha3Update(&d->sha3Context, reinterpret_cast<const BitSequence *>(data), length*8);
         break;
     case Sha3_384:
+    case Keccak_384:
         sha3Update(&d->sha3Context, reinterpret_cast<const BitSequence *>(data), length*8);
         break;
     case Sha3_512:
+    case Keccak_512:
         sha3Update(&d->sha3Context, reinterpret_cast<const BitSequence *>(data), length*8);
         break;
 #endif
@@ -463,19 +492,35 @@ QByteArray QCryptographicHash::result() const
         break;
     }
     case Sha3_224: {
-        d->sha3Finish(224);
+        d->sha3Finish(224, QCryptographicHashPrivate::Sha3Variant::Sha3);
         break;
     }
     case Sha3_256: {
-        d->sha3Finish(256);
+        d->sha3Finish(256, QCryptographicHashPrivate::Sha3Variant::Sha3);
         break;
     }
     case Sha3_384: {
-        d->sha3Finish(384);
+        d->sha3Finish(384, QCryptographicHashPrivate::Sha3Variant::Sha3);
         break;
     }
     case Sha3_512: {
-        d->sha3Finish(512);
+        d->sha3Finish(512, QCryptographicHashPrivate::Sha3Variant::Sha3);
+        break;
+    }
+    case Keccak_224: {
+        d->sha3Finish(224, QCryptographicHashPrivate::Sha3Variant::Keccak);
+        break;
+    }
+    case Keccak_256: {
+        d->sha3Finish(256, QCryptographicHashPrivate::Sha3Variant::Keccak);
+        break;
+    }
+    case Keccak_384: {
+        d->sha3Finish(384, QCryptographicHashPrivate::Sha3Variant::Keccak);
+        break;
+    }
+    case Keccak_512: {
+        d->sha3Finish(512, QCryptographicHashPrivate::Sha3Variant::Keccak);
         break;
     }
 #endif

src/corelib/tools/qcryptographichash.h

@@ -68,7 +68,12 @@ public:
         Sha3_224,
         Sha3_256,
         Sha3_384,
-        Sha3_512
+        Sha3_512,
+        // ### Qt 6: remove the Keccak enumerators
+        Keccak_224,
+        Keccak_256,
+        Keccak_384,
+        Keccak_512
 #endif
     };
     Q_ENUM(Algorithm)

src/corelib/tools/qmessageauthenticationcode.cpp

@@ -100,12 +100,16 @@ static int qt_hash_block_size(QCryptographicHash::Algorithm method)
     case QCryptographicHash::Sha512:
         return SHA512_Message_Block_Size;
     case QCryptographicHash::Sha3_224:
+    case QCryptographicHash::Keccak_224:
         return 144;
     case QCryptographicHash::Sha3_256:
+    case QCryptographicHash::Keccak_256:
         return 136;
     case QCryptographicHash::Sha3_384:
+    case QCryptographicHash::Keccak_384:
         return 104;
     case QCryptographicHash::Sha3_512:
+    case QCryptographicHash::Keccak_512:
         return 72;
     }
     return 0;