From c3f59f3e7ba11b64e798cbf710c00a8310317a3e Mon Sep 17 00:00:00 2001
From: Emman <emman.sun@cargosmart.com>
Date: Wed, 24 Mar 2021 16:20:01 +0800
Subject: [PATCH] MAGIC - avoid nil message passed in

---
 sm2/sm2.go      |  3 +++
 sm4/asm_amd64.s | 37 ++++++++-----------------------------
 2 files changed, 11 insertions(+), 29 deletions(-)

diff --git a/sm2/sm2.go b/sm2/sm2.go
index d45c8a0..20fda07 100644
--- a/sm2/sm2.go
+++ b/sm2/sm2.go
@@ -189,6 +189,9 @@ func calculateC3(curve elliptic.Curve, x2, y2 *big.Int, msg []byte) []byte {
 func Encrypt(random io.Reader, pub *ecdsa.PublicKey, msg []byte, opts *EncrypterOpts) ([]byte, error) {
 	curve := pub.Curve
 	msgLen := len(msg)
+	if msgLen == 0 {
+		return nil, nil
+	}
 	if opts == nil {
 		opts = &defaultEncrypterOpts
 	}
diff --git a/sm4/asm_amd64.s b/sm4/asm_amd64.s
index 6eb9cea..475565b 100644
--- a/sm4/asm_amd64.s
+++ b/sm4/asm_amd64.s
@@ -56,21 +56,9 @@ DATA r24_mask<>+0x00(SB)/8, $0x0407060500030201
 DATA r24_mask<>+0x08(SB)/8, $0x0C0F0E0D080B0A09  
 GLOBL r24_mask<>(SB), RODATA, $16
 
-DATA fk00_mask<>+0x00(SB)/8, $0xa3b1bac6a3b1bac6
-DATA fk00_mask<>+0x08(SB)/8, $0xa3b1bac6a3b1bac6  
-GLOBL fk00_mask<>(SB), RODATA, $16
-
-DATA fk01_mask<>+0x00(SB)/8, $0x56aa335056aa3350
-DATA fk01_mask<>+0x08(SB)/8, $0x56aa335056aa3350  
-GLOBL fk01_mask<>(SB), RODATA, $16
-
-DATA fk02_mask<>+0x00(SB)/8, $0x677d9197677d9197
-DATA fk02_mask<>+0x08(SB)/8, $0x677d9197677d9197  
-GLOBL fk02_mask<>(SB), RODATA, $16
-
-DATA fk03_mask<>+0x00(SB)/8, $0xb27022dcb27022dc
-DATA fk03_mask<>+0x08(SB)/8, $0xb27022dcb27022dc  
-GLOBL fk03_mask<>(SB), RODATA, $16
+DATA fk_mask<>+0x00(SB)/8, $0x56aa3350a3b1bac6
+DATA fk_mask<>+0x08(SB)/8, $0xb27022dc677d9197
+GLOBL fk_mask<>(SB), RODATA, $16
 
 #define SM4_SBOX(x, y) \
   ;                                   \ //#############################  inner affine ############################//
@@ -139,21 +127,12 @@ TEXT ·expandKeyAsm(SB),NOSPLIT,$0
   MOVQ  enc+16(FP), DX
   MOVQ  dec+24(FP), DI
 
-  PINSRD $0, 0(AX), t0
+  MOVUPS 0(AX), t0
   PSHUFB flip_mask<>(SB), t0
-  PXOR fk00_mask<>(SB), t0
-
-  PINSRD $0, 4(AX), t1
-  PSHUFB flip_mask<>(SB), t1
-  PXOR fk01_mask<>(SB), t1
-
-  PINSRD $0, 8(AX), t2
-  PSHUFB flip_mask<>(SB), t2
-  PXOR fk02_mask<>(SB), t2
-
-  PINSRD $0, 12(AX), t3
-  PSHUFB flip_mask<>(SB), t3
-  PXOR fk03_mask<>(SB), t3
+  PXOR fk_mask<>(SB), t0
+  PSHUFD $1, t0, t1
+  PSHUFD $2, t0, t2
+  PSHUFD $3, t0, t3
 
   XORL CX, CX
   MOVL $112, SI