introduce separate aes_desc

`aes_desc` and `aes_enc_desc` now do auto-detection of the best suitable
AES implementation for the platform.

Signed-off-by: Steffen Jaeckel <[email protected]>

Author: sjaeckel

doc/crypt.tex

@@ -614,7 +614,10 @@ \subsection{Simple Encryption Demonstration}
      \hline SAFER+ & saferp\_desc &16 & 16, 24, 32 & 8, 12, 16 & 4 \\
      \hline AES & aes\_desc & 16 & 16, 24, 32 & 10, 12, 14 & 6 \\
                 & aes\_enc\_desc & 16 & 16, 24, 32 & 10, 12, 14 & 6 \\
-                & aesni\_desc & 16 & 16, 24, 32 & 10, 12, 14 & 6 \\
+                & rijndael\_desc & 16 & 16, 24, 32 & 10, 12, 14 & 6 \\
+                & rijndael\_enc\_desc & 16 & 16, 24, 32 & 10, 12, 14 & 6 \\
+     \hline AES & aesni\_desc & 16 & 16, 24, 32 & 10, 12, 14 & 6 \\
+            (only on x86 with SSE4.1) &&&&& \\
      \hline Twofish & twofish\_desc & 16 & 16, 24, 32 & 16 & 7 \\
      \hline DES & des\_desc & 8 & 8 & 16 & 13 \\
      \hline 3DES (EDE mode) & des3\_desc & 8 & 16, 24 & 16 & 14 \\
@@ -640,24 +643,30 @@ \subsection{Notes}
 \begin{small}
 \begin{enumerate}
 \item
-For AES, (also known as Rijndael) there are four descriptors which complicate issues a little.  The descriptors
-rijndael\_desc and rijndael\_enc\_desc provide the cipher named \textit{rijndael}.  The descriptors aes\_desc and
-aes\_enc\_desc provide the cipher name \textit{aes}.  Functionally both \textit{rijndael} and \textit{aes} are the same cipher.  The
+For AES, (also known as Rijndael) there are multiple descriptors which complicate issues a little.  As of FIXME-version-next
+the library also integrates hardware-accelerated AES operations (e.g. AES-NI on amd64 with SSE4.1).  Therefor the functionality of
+the descriptors for the AES algorithm has changed.  The rijndael\_desc and rijndael\_enc\_desc descriptors provide the cipher
+named \textit{rijndael} which contains the software implementation of the algorithm.  The descriptors aes\_desc and aes\_enc\_desc
+provide the cipher named \textit{aes} and implement an auto-detection mechanism that chooses between the software-only \textit{rijndael}
+and the hardware-accelerated implementation.
+
+Functionally both \textit{rijndael} and \textit{aes} are the same cipher.  The
 only difference is when you call find\_cipher() you have to pass the correct name.  The cipher descriptors with \textit{enc}
 in the middle (e.g. rijndael\_enc\_desc) are related to an implementation of Rijndael with only the encryption routine
 and tables.  The decryption and self--test function pointers of both \textit{encrypt only} descriptors are set to \textbf{NULL} and
 should not be called.
 
 The \textit{encrypt only} descriptors are useful for applications that only use the encryption function of the cipher.  Algorithms such
-as EAX, PMAC and OMAC only require the encryption function.  So far this \textit{encrypt only} functionality has only been implemented for
-Rijndael as it makes the most sense for this cipher.
+as EAX, PMAC and OMAC or the CTR mode only require the encryption function.  So far this \textit{encrypt only} functionality has only
+been implemented for Rijndael as it makes the most sense for this cipher.
 
 \item
 Note that for \textit{DES} and \textit{3DES} they use 8 and 24 byte keys but only 7 and 21 [respectively] bytes of the keys are in
 fact used for the purposes of encryption.  My suggestion is just to use random 8/24 byte keys instead of trying to make a 8/24
 byte string from the real 7/21 byte key.
 
-For \textit{3DES} exists a two-key mode, that can be initialized by calling the setup function with a \textit{keylen} of 16. This results in the re-usage of key \textit{K1} as key \textit{K3}. This mode has been specified as \textit{Keying Option 2} in FIPS 46-3.
+For \textit{3DES} exists a two-key mode, that can be initialized by calling the setup function with a \textit{keylen} of 16.
+This results in the re-usage of key \textit{K1} as key \textit{K3}. This mode has been specified as \textit{Keying Option 2} in FIPS 46-3.
 
 \item
 Note that \textit{Twofish} has additional configuration options (Figure \ref{fig:twofishopts}) that take place at build time.  These options are found in

helper.pl

@@ -316,7 +316,7 @@ sub process_makefiles {
   my @t = qw();
   find({ no_chdir => 1, wanted => sub { push @t, $_ if $_ =~ /(common|no_prng|_tests?|test).c$/ } }, 'tests');
 
-  my @o = sort ('src/ciphers/aes/aes_enc.o', map { my $x = $_; $x =~ s/\.c$/.o/; $x } @c);
+  my @o = sort ('src/ciphers/aes/aes_enc.o', 'src/ciphers/aes/aes_enc_desc.o', map { my $x = $_; $x =~ s/\.c$/.o/; $x } @c);
   my $var_o = prepare_variable("OBJECTS", @o);
   my $var_h = prepare_variable("HEADERS_PUB", (sort @h));
   (my $var_obj = $var_o) =~ s/\.o\b/.obj/sg;

makefile

@@ -46,6 +46,11 @@ LTC_EXTRALIBS += $(EXTRALIBS)
 
 #AES comes in two flavours... enc+dec and enc
 src/ciphers/aes/aes_enc.o: src/ciphers/aes/aes.c src/ciphers/aes/aes_tab.c
+ifneq ($V,1)
+	@echo "   * ${CC} $@" ${silent_echo}
+endif
+	${silent} ${CC} ${LTC_CFLAGS} -DENCRYPT_ONLY -c $< -o $@
+src/ciphers/aes/aes_enc_desc.o: src/ciphers/aes/aes_desc.c
 ifneq ($V,1)
 	@echo "   * ${CC} $@" ${silent_echo}
 endif

makefile.mingw

@@ -246,6 +246,8 @@ default: $(LIBMAIN_S)
 #SPECIAL: AES comes in two flavours - enc+dec and enc-only
 src/ciphers/aes/aes_enc.o: src/ciphers/aes/aes.c src/ciphers/aes/aes_tab.c
 	$(CC) $(LTC_CFLAGS) -DENCRYPT_ONLY -c src/ciphers/aes/aes.c -o src/ciphers/aes/aes_enc.o
+src/ciphers/aes/aes_enc_desc.o: src/ciphers/aes/aes.c
+	$(CC) $(LTC_CFLAGS) -DENCRYPT_ONLY -c src/ciphers/aes/aes_desc.c -o src/ciphers/aes/aes_enc_desc.o
 
 #SPECIAL: these are the rules to make certain object files
 src/ciphers/aes/aes.o: src/ciphers/aes/aes.c src/ciphers/aes/aes_tab.c

makefile.msvc

@@ -239,6 +239,8 @@ default: $(LIBMAIN_S)
 #SPECIAL: AES comes in two flavours - enc+dec and enc-only
 src/ciphers/aes/aes_enc.obj: src/ciphers/aes/aes.c src/ciphers/aes/aes_tab.c
 	$(CC) $(LTC_CFLAGS) /DENCRYPT_ONLY /c src/ciphers/aes/aes.c /Fosrc/ciphers/aes/aes_enc.obj
+src/ciphers/aes/aes_enc_desc.obj: src/ciphers/aes/aes_desc.c
+	$(CC) $(LTC_CFLAGS) /DENCRYPT_ONLY /c src/ciphers/aes/aes_desc.c /Fosrc/ciphers/aes/aes_enc_desc.obj
 
 #SPECIAL: these are the rules to make certain object files
 src/ciphers/aes/aes.obj: src/ciphers/aes/aes.c src/ciphers/aes/aes_tab.c

makefile.shared

@@ -70,6 +70,8 @@ endif
 #ciphers come in two flavours... enc+dec and enc
 src/ciphers/aes/aes_enc.o: src/ciphers/aes/aes.c src/ciphers/aes/aes_tab.c
 	$(LTCOMPILE) $(LTC_CFLAGS) $(CPPFLAGS) $(LTC_LDFLAGS) -DENCRYPT_ONLY -c src/ciphers/aes/aes.c -o src/ciphers/aes/aes_enc.o
+src/ciphers/aes/aes_enc_desc.o: src/ciphers/aes/aes_desc.c
+	$(LTCOMPILE) $(LTC_CFLAGS) $(CPPFLAGS) $(LTC_LDFLAGS) -DENCRYPT_ONLY -c src/ciphers/aes/aes_desc.c -o src/ciphers/aes/aes_enc_desc.o
 
 .c.o:
 	$(LTCOMPILE) $(LTC_CFLAGS) $(CPPFLAGS) $(LTC_LDFLAGS) -o $@ -c $<

makefile.unix

@@ -256,6 +256,8 @@ default: $(LIBMAIN_S)
 #SPECIAL: AES comes in two flavours - enc+dec and enc-only
 src/ciphers/aes/aes_enc.o: src/ciphers/aes/aes.c src/ciphers/aes/aes_tab.c
 	$(CC) $(LTC_CFLAGS) -DENCRYPT_ONLY -c src/ciphers/aes/aes.c -o src/ciphers/aes/aes_enc.o
+src/ciphers/aes/aes_enc_desc.o: src/ciphers/aes/aes_desc.c
+	$(CC) $(LTC_CFLAGS) -DENCRYPT_ONLY -c src/ciphers/aes/aes_desc.c -o src/ciphers/aes/aes_enc_desc.o
 
 #SPECIAL: these are the rules to make certain object files
 src/ciphers/aes/aes.o: src/ciphers/aes/aes.c src/ciphers/aes/aes_tab.c

makefile_include.mk

@@ -427,6 +427,7 @@ src/hashes/sha2/sha512_224.o: src/hashes/sha2/sha512.c src/hashes/sha2/sha512_22
 src/hashes/sha2/sha512_256.o: src/hashes/sha2/sha512.c src/hashes/sha2/sha512_256.c
 src/hashes/whirl/whirl.o: src/hashes/whirl/whirl.c src/hashes/whirl/whirltab.c
 
+
 $(DOBJECTS): LTC_CFLAGS := -Itests $(LTC_CFLAGS)
 $(TOBJECTS): LTC_CFLAGS := -Itests $(LTC_CFLAGS)
 

src/ciphers/aes/aes.c

@@ -44,15 +44,6 @@ const struct ltc_cipher_descriptor rijndael_desc =
     NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
 };
 
-const struct ltc_cipher_descriptor aes_desc =
-{
-    "aes",
-    6,
-    16, 32, 16, 10,
-    SETUP, ECB_ENC, ECB_DEC, ECB_TEST, ECB_DONE, ECB_KS,
-    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
-};
-
 #else
 
 #define SETUP    rijndael_enc_setup
@@ -69,15 +60,6 @@ const struct ltc_cipher_descriptor rijndael_enc_desc =
     NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
 };
 
-const struct ltc_cipher_descriptor aes_enc_desc =
-{
-    "aes",
-    6,
-    16, 32, 16, 10,
-    SETUP, ECB_ENC, NULL, NULL, ECB_DONE, ECB_KS,
-    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
-};
-
 #endif
 
 #define LTC_AES_TAB_C

src/ciphers/aes/aes_desc.c

@@ -0,0 +1,244 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+/* Auto-detection of AES implementation by Steffen Jaeckel */
+/**
+  @file aes_desc.c
+  Run-time detection of correct AES implementation
+*/
+
+#include "tomcrypt_private.h"
+
+#if defined(LTC_RIJNDAEL)
+
+#ifndef ENCRYPT_ONLY
+
+#define AES_SETUP aes_setup
+#define AES_ENC   aes_ecb_encrypt
+#define AES_DEC   aes_ecb_decrypt
+#define AES_DONE  aes_done
+#define AES_TEST  aes_test
+#define AES_KS    aes_keysize
+
+const struct ltc_cipher_descriptor aes_desc =
+{
+    "aes",
+    6,
+    16, 32, 16, 10,
+    AES_SETUP, AES_ENC, AES_DEC, AES_TEST, AES_DONE, AES_KS,
+    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
+};
+
+#else
+
+#define AES_SETUP aes_enc_setup
+#define AES_ENC   aes_enc_ecb_encrypt
+#define AES_DONE  aes_enc_done
+#define AES_KS    aes_enc_keysize
+
+const struct ltc_cipher_descriptor aes_enc_desc =
+{
+    "aes",
+    6,
+    16, 32, 16, 10,
+    AES_SETUP, AES_ENC, NULL, NULL, AES_DONE, AES_KS,
+    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
+};
+
+#endif
+
+/* Code partially borrowed from https://software.intel.com/content/www/us/en/develop/articles/intel-sha-extensions.html */
+#if defined(LTC_HAS_AES_NI)
+static LTC_INLINE int s_aesni_is_supported(void)
+{
+   static int initialized = 0, is_supported = 0;
+
+   if (initialized == 0) {
+      int a, b, c, d;
+
+      /* Look for CPUID.1.0.ECX[25]
+       * EAX = 1, ECX = 0
+       */
+      a = 1;
+      c = 0;
+
+      asm volatile ("cpuid"
+           :"=a"(a), "=b"(b), "=c"(c), "=d"(d)
+           :"a"(a), "c"(c)
+          );
+
+      is_supported = ((c >> 25) & 1);
+      initialized = 1;
+   }
+
+   return is_supported;
+}
+
+#ifndef ENCRYPT_ONLY
+int aesni_is_supported(void)
+{
+   return s_aesni_is_supported();
+}
+#endif
+#endif
+
+ /**
+    Initialize the AES (Rijndael) block cipher
+    @param key The symmetric key you wish to pass
+    @param keylen The key length in bytes
+    @param num_rounds The number of rounds desired (0 for default)
+    @param skey The key in as scheduled by this function.
+    @return CRYPT_OK if successful
+ */
+int AES_SETUP(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
+{
+#ifdef LTC_HAS_AES_NI
+   if (s_aesni_is_supported()) {
+      return aesni_setup(key, keylen, num_rounds, skey);
+   }
+#endif
+   /* Last resort, software AES */
+   return rijndael_setup(key, keylen, num_rounds, skey);
+}
+
+/**
+  Encrypts a block of text with AES
+  @param pt The input plaintext (16 bytes)
+  @param ct The output ciphertext (16 bytes)
+  @param skey The key as scheduled
+  @return CRYPT_OK if successful
+*/
+int AES_ENC(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
+{
+#ifdef LTC_HAS_AES_NI
+   if (s_aesni_is_supported()) {
+      return aesni_ecb_encrypt(pt, ct, skey);
+   }
+#endif
+   return rijndael_ecb_encrypt(pt, ct, skey);
+}
+
+
+/**
+  Decrypts a block of text with AES
+  @param ct The input ciphertext (16 bytes)
+  @param pt The output plaintext (16 bytes)
+  @param skey The key as scheduled
+  @return CRYPT_OK if successful
+*/
+int AES_DEC(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
+{
+#ifdef LTC_HAS_AES_NI
+   if (s_aesni_is_supported()) {
+      return aesni_ecb_decrypt(ct, pt, skey);
+   }
+#endif
+   return rijndael_ecb_decrypt(ct, pt, skey);
+}
+
+/**
+  Performs a self-test of the AES block cipher
+  @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
+*/
+int AES_TEST(void)
+{
+ #ifndef LTC_TEST
+    return CRYPT_NOP;
+ #else
+ int err;
+ static const struct {
+     int keylen;
+     unsigned char key[32], pt[16], ct[16];
+ } tests[] = {
+    { 16,
+      { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+        0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
+      { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
+        0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff },
+      { 0x69, 0xc4, 0xe0, 0xd8, 0x6a, 0x7b, 0x04, 0x30,
+        0xd8, 0xcd, 0xb7, 0x80, 0x70, 0xb4, 0xc5, 0x5a }
+    }, {
+      24,
+      { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+        0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+        0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17 },
+      { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
+        0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff },
+      { 0xdd, 0xa9, 0x7c, 0xa4, 0x86, 0x4c, 0xdf, 0xe0,
+        0x6e, 0xaf, 0x70, 0xa0, 0xec, 0x0d, 0x71, 0x91 }
+    }, {
+      32,
+      { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+        0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+        0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+        0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f },
+      { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
+        0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff },
+      { 0x8e, 0xa2, 0xb7, 0xca, 0x51, 0x67, 0x45, 0xbf,
+        0xea, 0xfc, 0x49, 0x90, 0x4b, 0x49, 0x60, 0x89 }
+    }
+ };
+
+  symmetric_key key;
+  unsigned char tmp[2][16];
+  int i, y;
+
+  for (i = 0; i < (int)(sizeof(tests)/sizeof(tests[0])); i++) {
+    zeromem(&key, sizeof(key));
+    if ((err = aes_setup(tests[i].key, tests[i].keylen, 0, &key)) != CRYPT_OK) {
+       return err;
+    }
+
+    aes_ecb_encrypt(tests[i].pt, tmp[0], &key);
+    aes_ecb_decrypt(tmp[0], tmp[1], &key);
+    if (compare_testvector(tmp[0], 16, tests[i].ct, 16, "AES Encrypt", i) ||
+          compare_testvector(tmp[1], 16, tests[i].pt, 16, "AES Decrypt", i)) {
+        return CRYPT_FAIL_TESTVECTOR;
+    }
+
+    /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
+    for (y = 0; y < 16; y++) tmp[0][y] = 0;
+    for (y = 0; y < 1000; y++) aes_ecb_encrypt(tmp[0], tmp[0], &key);
+    for (y = 0; y < 1000; y++) aes_ecb_decrypt(tmp[0], tmp[0], &key);
+    for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
+  }
+  return CRYPT_OK;
+ #endif
+}
+
+
+/** Terminate the context
+   @param skey    The scheduled key
+*/
+void AES_DONE(symmetric_key *skey)
+{
+  LTC_UNUSED_PARAM(skey);
+}
+
+
+/**
+  Gets suitable key size
+  @param keysize [in/out] The length of the recommended key (in bytes).  This function will store the suitable size back in this variable.
+  @return CRYPT_OK if the input key size is acceptable.
+*/
+int AES_KS(int *keysize)
+{
+   LTC_ARGCHK(keysize != NULL);
+
+   if (*keysize < 16) {
+      return CRYPT_INVALID_KEYSIZE;
+   }
+   if (*keysize < 24) {
+      *keysize = 16;
+      return CRYPT_OK;
+   }
+   if (*keysize < 32) {
+      *keysize = 24;
+      return CRYPT_OK;
+   }
+   *keysize = 32;
+   return CRYPT_OK;
+}
+
+#endif
+