[PATCH 1/3] sm4: add XTS bulk processing

[Jussi Kivilinna]

* cipher/sm4.c (_gcry_sm4_xts_crypt): New.
(sm4_setkey): Set XTS bulk function.
--

Benchmark on Ryzen 5800X:

Before:
 SM4            |  nanosecs/byte   mebibytes/sec   cycles/byte  auto Mhz
        XTS enc |      7.28 ns/B     131.0 MiB/s     35.31 c/B      4850
        XTS dec |      7.29 ns/B     130.9 MiB/s     35.34 c/B      4850

After (4.8x faster):
 SM4            |  nanosecs/byte   mebibytes/sec   cycles/byte  auto Mhz
        XTS enc |      1.49 ns/B     638.6 MiB/s      7.24 c/B      4850
        XTS dec |      1.49 ns/B     639.3 MiB/s      7.24 c/B      4850

Signed-off-by: Jussi Kivilinna <jussi.kivilinna at iki.fi>
---
 cipher/sm4.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/cipher/sm4.c b/cipher/sm4.c
index 4815b184..600850e2 100644
--- a/cipher/sm4.c
+++ b/cipher/sm4.c
@@ -97,6 +97,9 @@ static void _gcry_sm4_cbc_dec (void *context, unsigned char *iv,
 static void _gcry_sm4_cfb_dec (void *context, unsigned char *iv,
 			       void *outbuf_arg, const void *inbuf_arg,
 			       size_t nblocks);
+static void _gcry_sm4_xts_crypt (void *context, unsigned char *tweak,
+                                 void *outbuf_arg, const void *inbuf_arg,
+                                 size_t nblocks, int encrypt);
 static size_t _gcry_sm4_ocb_crypt (gcry_cipher_hd_t c, void *outbuf_arg,
 				   const void *inbuf_arg, size_t nblocks,
 				   int encrypt);
@@ -492,6 +495,7 @@ sm4_setkey (void *context, const byte *key, const unsigned keylen,
   bulk_ops->cbc_dec = _gcry_sm4_cbc_dec;
   bulk_ops->cfb_dec = _gcry_sm4_cfb_dec;
   bulk_ops->ctr_enc = _gcry_sm4_ctr_enc;
+  bulk_ops->xts_crypt = _gcry_sm4_xts_crypt;
   bulk_ops->ocb_crypt = _gcry_sm4_ocb_crypt;
   bulk_ops->ocb_auth  = _gcry_sm4_ocb_auth;
 
@@ -954,6 +958,37 @@ _gcry_sm4_cfb_dec(void *context, unsigned char *iv,
     _gcry_burn_stack(burn_stack_depth);
 }
 
+/* Bulk encryption/decryption of complete blocks in XTS mode. */
+static void
+_gcry_sm4_xts_crypt (void *context, unsigned char *tweak, void *outbuf_arg,
+                     const void *inbuf_arg, size_t nblocks, int encrypt)
+{
+  SM4_context *ctx = context;
+  unsigned char *outbuf = outbuf_arg;
+  const unsigned char *inbuf = inbuf_arg;
+  int burn_stack_depth = 0;
+
+  /* Process remaining blocks. */
+  if (nblocks)
+    {
+      crypt_blk1_8_fn_t crypt_blk1_8 = sm4_get_crypt_blk1_8_fn(ctx);
+      u32 *rk = encrypt ? ctx->rkey_enc : ctx->rkey_dec;
+      unsigned char tmpbuf[16 * 8];
+      unsigned int tmp_used = 16;
+      size_t nburn;
+
+      nburn = bulk_xts_crypt_128(rk, crypt_blk1_8, outbuf, inbuf, nblocks,
+                                 tweak, tmpbuf, sizeof(tmpbuf) / 16,
+                                 &tmp_used);
+      burn_stack_depth = nburn > burn_stack_depth ? nburn : burn_stack_depth;
+
+      wipememory(tmpbuf, tmp_used);
+    }
+
+  if (burn_stack_depth)
+    _gcry_burn_stack(burn_stack_depth);
+}
+
 /* Bulk encryption/decryption of complete blocks in OCB mode. */
 static size_t
 _gcry_sm4_ocb_crypt (gcry_cipher_hd_t c, void *outbuf_arg,
-- 
2.34.1