Windows: use separate assembly files for RDRAND and RDSEED in order to fix a mysterious crash when MASM_RDSEED_GenerateBlock is called after MASM_RDRAND_GenerateBlock.

author: Mounir IDRASSI <mounir.idrassi@idrix.fr> 2019-10-30 00:15:28 +0100
committer: Mounir IDRASSI <mounir.idrassi@idrix.fr> 2019-10-30 08:52:55 +0100
commit: 7a35ecb154fc979d46dea8d97d0ad97fd4ae4140 (patch)
tree: 185a5ed69b1fd7cdde2d3b0e68841e76e1c13d8b /src/Crypto
parent: 3b5d4771a0af5b4fc89ec77f43826b9ae2544949 (diff)
download: VeraCrypt-7a35ecb154fc979d46dea8d97d0ad97fd4ae4140.tar.gz
VeraCrypt-7a35ecb154fc979d46dea8d97d0ad97fd4ae4140.zip
6 files changed, 291 insertions, 228 deletions
diff --git a/src/Crypto/Crypto.vcxproj b/src/Crypto/Crypto.vcxproj
index 027a87e0..c6e0aac5 100644
--- a/src/Crypto/Crypto.vcxproj
+++ b/src/Crypto/Crypto.vcxproj
@@ -403,6 +403,21 @@
       <Outputs Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">$(TargetDir)\%(Filename).obj;%(Outputs)</Outputs>
       <Outputs Condition="'$(Configuration)|$(Platform)'=='Release|x64'">$(TargetDir)\%(Filename).obj;%(Outputs)</Outputs>
     </CustomBuild>
+    <CustomBuild Include="rdseed_ml.asm">
+      <FileType>Document</FileType>
+      <Command Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">echo %(Filename)%(Extension) &amp; ml64.exe /nologo /D_M_X64 /W3 /Cx /Zi /Fo "$(TargetDir)\%(Filename).obj" /c "%(FullPath)"
+</Command>
+      <Command Condition="'$(Configuration)|$(Platform)'=='Release|x64'">echo %(Filename)%(Extension) &amp; ml64.exe /nologo /D_M_X64 /W3 /Cx /Zi /Fo "$(TargetDir)\%(Filename).obj" /c "%(FullPath)"
+</Command>
+      <Command Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">echo %(Filename)%(Extension) &amp; ml.exe /nologo /D_M_X86 /W3 /Cx /Zi /safeseh /Fo "$(TargetDir)\%(Filename).obj" /c "%(FullPath)"
+</Command>
+      <Command Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">echo %(Filename)%(Extension) &amp; ml.exe /nologo /D_M_X86 /W3 /Cx /Zi /safeseh /Fo "$(TargetDir)\%(Filename).obj" /c "%(FullPath)"
+</Command>
+      <Outputs Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">$(TargetDir)\%(Filename).obj;%(Outputs)</Outputs>
+      <Outputs Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">$(TargetDir)\%(Filename).obj;%(Outputs)</Outputs>
+      <Outputs Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">$(TargetDir)\%(Filename).obj;%(Outputs)</Outputs>
+      <Outputs Condition="'$(Configuration)|$(Platform)'=='Release|x64'">$(TargetDir)\%(Filename).obj;%(Outputs)</Outputs>
+    </CustomBuild>
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
diff --git a/src/Crypto/Crypto.vcxproj.filters b/src/Crypto/Crypto.vcxproj.filters
index e7b3c3a5..541a0867 100644
--- a/src/Crypto/Crypto.vcxproj.filters
+++ b/src/Crypto/Crypto.vcxproj.filters
@@ -217,5 +217,8 @@
     <CustomBuild Include="rdrand_ml.asm">
       <Filter>Source Files</Filter>
     </CustomBuild>
+    <CustomBuild Include="rdseed_ml.asm">
+      <Filter>Source Files</Filter>
+    </CustomBuild>
   </ItemGroup>
 </Project>
 \ No newline at end of file
diff --git a/src/Crypto/Makefile.inc b/src/Crypto/Makefile.inc
index 86b7a6fa..c8d2dfdf 100644
--- a/src/Crypto/Makefile.inc
+++ b/src/Crypto/Makefile.inc
@@ -60,4 +60,8 @@ TC_ASM_ERR_LOG = ..\Driver\build_errors_asm.log
 	
 "$(OBJ_PATH)\$(O)\rdrand_ml.obj": rdrand_ml.asm
 	$(VC_MLEXE) $(VC_MLFLAGS) /Fo "$@" /c rdrand_ml.asm 2>$(TC_ASM_ERR_LOG)
+	
+"$(OBJ_PATH)\$(O)\rdseed_ml.obj": rdseed_ml.asm
+	$(VC_MLEXE) $(VC_MLFLAGS) /Fo "$@" /c rdseed_ml.asm 2>$(TC_ASM_ERR_LOG)
+
 
diff --git a/src/Crypto/Sources b/src/Crypto/Sources
index 2db68a7a..9a1bef14 100644
--- a/src/Crypto/Sources
+++ b/src/Crypto/Sources
@@ -25,6 +25,7 @@ SOURCES = \
 	gost89_$(TC_ARCH).asm \
 	Aes_hw_cpu.asm \
 	rdrand_ml.asm \
+	rdseed_ml.asm \
 	Aeskey.c \
 	Aestab.c \
 	chacha-xmm.c \
diff --git a/src/Crypto/rdrand_ml.asm b/src/Crypto/rdrand_ml.asm
index 1579a155..4b85f7fc 100644
--- a/src/Crypto/rdrand_ml.asm
+++ b/src/Crypto/rdrand_ml.asm
@@ -1,9 +1,9 @@
 ;; rdrand.asm - written and placed in public domain by Jeffrey Walton and Uri Blumenthal.
 ;;              Copyright assigned to the Crypto++ project.
 
-;; This ASM file provides RDRAND and RDSEED to downlevel Microsoft tool chains.
-;; Everything "just works" under Visual Studio. Other platforms will have to
-;; run MASM/MASM-64 and then link to the object files.
+;; This ASM file provides RDRAND to downlevel Microsoft tool chains.
+;; Everything "just works" under Visual Studio. Other platforms will
+;; have to run MASM/MASM-64 and then link to the object files.
 
 ;; set ASFLAGS=/nologo /D_M_X86 /W3 /Cx /Zi /safeseh
 ;; set ASFLAGS64=/nologo /D_M_X64 /W3 /Cx /Zi
@@ -13,11 +13,10 @@
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-TITLE    MASM_RDRAND_GenerateBlock and MASM_RDSEED_GenerateBlock
-SUBTITLE Microsoft specific ASM code to utilize RDRAND and RDSEED for down level Microsoft toolchains
+TITLE    MASM_RDRAND_GenerateBlock source file
+SUBTITLE Microsoft specific ASM code to utilize RDRAND for down level Microsoft toolchains
 
 PUBLIC MASM_RDRAND_GenerateBlock
-PUBLIC MASM_RDSEED_GenerateBlock
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -38,7 +37,6 @@ IFDEF _M_X86    ;; Set via the command line
 
 ;; Fastcall calling conventions exports
 ALIAS <@MASM_RDRAND_GenerateBlock@8> = <MASM_RDRAND_GenerateBlock>
-ALIAS <@MASM_RDSEED_GenerateBlock@8> = <MASM_RDSEED_GenerateBlock>
 
 ENDIF
 
@@ -63,13 +61,13 @@ MASM_RDRAND_GenerateBlock PROC   ;; arg1:DWORD, arg2:DWORD
     bsize  EQU edx
 
             ;; Top of While loop
-GenerateBlock_Top:
+RDRAND_GenerateBlock_Top:
 
             ;; Check remaining size
     cmp     bsize, 0
-    je      GenerateBlock_Return
+    je      RDRAND_GenerateBlock_Return
 
-Call_RDRAND_EAX:
+RDRAND_Call_EAX:
             ;; RDRAND is not available prior to VS2012. Just emit
             ;;   the byte codes using DB. This is `rdrand eax`.
     DB      0Fh, 0C7h, 0F0h
@@ -78,46 +76,48 @@ Call_RDRAND_EAX:
             ;; If CF=0, a random number was not available.
 
             ;; Retry immediately
-    jnc     Call_RDRAND_EAX
+    jnc     RDRAND_Call_EAX
 
 RDRAND_succeeded:
 
     cmp     bsize, MWSIZE
-    jb      Partial_Machine_Word
+    jb      RDRAND_Partial_Machine_Word
 
-Full_Machine_Word:
+RDRAND_Full_Machine_Word:
 
     mov     DWORD PTR [buffer], eax
     add     buffer, MWSIZE        ;; No need for Intel Core 2 slow workarounds, like
     sub     bsize, MWSIZE         ;;   `lea buffer,[buffer+MWSIZE]` for faster adds
 
             ;; Continue
-    jmp     GenerateBlock_Top
+    jmp     RDRAND_GenerateBlock_Top
 
             ;; 1,2,3 bytes remain
-Partial_Machine_Word:
+RDRAND_Partial_Machine_Word:
 
             ;; Test bit 1 to see if size is at least 2
     test    bsize, 2
-    jz      Bit_1_Not_Set
+    jz      RDRAND_Bit_1_Not_Set
 
     mov     WORD PTR [buffer], ax
     shr     eax, 16
     add     buffer, 2
 
-Bit_1_Not_Set:
+RDRAND_Bit_1_Not_Set:
 
             ;; Test bit 0 to see if size is at least 1
     test    bsize, 1
-    jz      Bit_0_Not_Set
+    jz      RDRAND_Bit_0_Not_Set
 
     mov     BYTE PTR [buffer], al
+    ;; shr     ax, 8
+    ;; add     buffer, 1
 
-Bit_0_Not_Set:
+RDRAND_Bit_0_Not_Set:
 
             ;; We've hit all the bits
 
-GenerateBlock_Return:
+RDRAND_GenerateBlock_Return:
 
             ;; Clear artifacts
     xor     eax, eax
@@ -127,9 +127,6 @@ MASM_RDRAND_GenerateBlock ENDP
 
 ENDIF    ;; _M_X86
 
-OPTION PROLOGUE:PrologueDef
-OPTION EPILOGUE:EpilogueDef
-
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
@@ -151,13 +148,13 @@ MASM_RDRAND_GenerateBlock PROC   ;; arg1:QWORD, arg2:QWORD
     bsize  EQU rdx
 
             ;; Top of While loop
-GenerateBlock_Top:
+RDRAND_GenerateBlock_Top:
 
             ;; Check remaining size
     cmp     bsize, 0
-    je      GenerateBlock_Return
+    je      RDRAND_GenerateBlock_Return
 
-Call_RDRAND_RAX:
+RDRAND_Call_RAX:
             ;; RDRAND is not available prior to VS2012. Just emit
             ;;   the byte codes using DB. This is `rdrand rax`.
     DB      048h, 0Fh, 0C7h, 0F0h
@@ -166,254 +163,67 @@ Call_RDRAND_RAX:
             ;; If CF=0, a random number was not available.
 
             ;; Retry immediately
-    jnc     Call_RDRAND_RAX
+    jnc     RDRAND_Call_RAX
 
 RDRAND_succeeded:
 
     cmp     bsize, MWSIZE
-    jb      Partial_Machine_Word
-
-Full_Machine_Word:
-
-    mov     QWORD PTR [buffer], rax
-    add     buffer, MWSIZE
-    sub     bsize, MWSIZE
-
-            ;; Continue
-    jmp     GenerateBlock_Top
-
-            ;; 1,2,3,4,5,6,7 bytes remain
-Partial_Machine_Word:
-
-            ;; Test bit 2 to see if size is at least 4
-    test    bsize, 4
-    jz      Bit_2_Not_Set
-
-    mov     DWORD PTR [buffer], eax
-    shr     rax, 32
-    add     buffer, 4
-
-Bit_2_Not_Set:
-
-            ;; Test bit 1 to see if size is at least 2
-    test    bsize, 2
-    jz      Bit_1_Not_Set
-
-    mov     WORD PTR [buffer], ax
-    shr     eax, 16
-    add     buffer, 2
-
-Bit_1_Not_Set:
-
-            ;; Test bit 0 to see if size is at least 1
-    test    bsize, 1
-    jz      Bit_0_Not_Set
-
-    mov     BYTE PTR [buffer], al
-
-Bit_0_Not_Set:
-
-            ;; We've hit all the bits
-
-GenerateBlock_Return:
-
-            ;; Clear artifacts
-    xor     rax, rax
-	ret
-
-MASM_RDRAND_GenerateBlock ENDP
-
-ENDIF    ;; _M_X64
-
-OPTION PROLOGUE:PrologueDef
-OPTION EPILOGUE:EpilogueDef
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-IFDEF _M_X86    ;; Set via the command line
-
-.CODE
-ALIGN   8
-OPTION PROLOGUE:NONE
-OPTION EPILOGUE:NONE
-
-;; No need for Load_Arguments due to fastcall
-;;   ECX (in): arg1, byte* buffer
-;;   EDX (in): arg2, size_t bsize
-
-MASM_RDSEED_GenerateBlock PROC   ;; arg1:DWORD, arg2:DWORD
-
-    MWSIZE EQU 04h    ;; machine word size
-    buffer EQU ecx
-    bsize  EQU edx
-
-            ;; Top of While loop
-GenerateBlock_Top:
-
-            ;; Check remaining size
-    cmp     bsize, 0
-    je      GenerateBlock_Return
-
-Call_RDSEED_EAX:
-            ;; RDSEED is not available prior to VS2012. Just emit
-            ;;   the byte codes using DB. This is `rdseed eax`.
-    DB      0Fh, 0C7h, 0F8h
-
-            ;; If CF=1, the number returned by RDSEED is valid.
-            ;; If CF=0, a random number was not available.
-
-            ;; Retry immediately
-    jnc     Call_RDSEED_EAX
-
-RDSEED_succeeded:
-
-    cmp     bsize, MWSIZE
-    jb      Partial_Machine_Word
-
-Full_Machine_Word:
-
-    mov     DWORD PTR [buffer], eax
-    add     buffer, MWSIZE        ;; No need for Intel Core 2 slow workarounds, like
-    sub     bsize, MWSIZE         ;;   `lea buffer,[buffer+MWSIZE]` for faster adds
-
-            ;; Continue
-    jmp     GenerateBlock_Top
-
-            ;; 1,2,3 bytes remain
-Partial_Machine_Word:
-
-            ;; Test bit 1 to see if size is at least 2
-    test    bsize, 2
-    jz      Bit_1_Not_Set
-
-    mov     WORD PTR [buffer], ax
-    shr     eax, 16
-    add     buffer, 2
-
-Bit_1_Not_Set:
-
-            ;; Test bit 0 to see if size is at least 1
-    test    bsize, 1
-    jz      Bit_0_Not_Set
-
-    mov     BYTE PTR [buffer], al
-
-Bit_0_Not_Set:
-
-            ;; We've hit all the bits
-
-GenerateBlock_Return:
-
-            ;; Clear artifacts
-    xor     eax, eax
-	ret
-
-MASM_RDSEED_GenerateBlock ENDP
-
-ENDIF    ;; _M_X86
+    jb      RDRAND_Partial_Machine_Word
 
-OPTION PROLOGUE:PrologueDef
-OPTION EPILOGUE:EpilogueDef
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-IFDEF _M_X64    ;; Set via the command line
-
-.CODE
-ALIGN   16
-OPTION PROLOGUE:NONE
-OPTION EPILOGUE:NONE
-
-;; No need for Load_Arguments due to fastcall
-;;   RCX (in): arg1, byte* buffer
-;;   RDX (in): arg2, size_t bsize
-
-MASM_RDSEED_GenerateBlock PROC   ;; arg1:QWORD, arg2:QWORD
-
-    MWSIZE EQU 08h    ;; machine word size
-    buffer EQU rcx
-    bsize  EQU rdx
-
-            ;; Top of While loop
-GenerateBlock_Top:
-
-            ;; Check remaining size
-    cmp     bsize, 0
-    je      GenerateBlock_Return
-
-Call_RDSEED_RAX:
-            ;; RDSEED is not available prior to VS2012. Just emit
-            ;;   the byte codes using DB. This is `rdseed rax`.
-    DB      048h, 0Fh, 0C7h, 0F8h
-
-            ;; If CF=1, the number returned by RDSEED is valid.
-            ;; If CF=0, a random number was not available.
-
-            ;; Retry immediately
-    jnc     Call_RDSEED_RAX
-
-RDSEED_succeeded:
-
-    cmp     bsize, MWSIZE
-    jb      Partial_Machine_Word
-
-Full_Machine_Word:
+RDRAND_Full_Machine_Word:
 
     mov     QWORD PTR [buffer], rax
     add     buffer, MWSIZE
     sub     bsize, MWSIZE
 
             ;; Continue
-    jmp     GenerateBlock_Top
+    jmp     RDRAND_GenerateBlock_Top
 
             ;; 1,2,3,4,5,6,7 bytes remain
-Partial_Machine_Word:
+RDRAND_Partial_Machine_Word:
 
             ;; Test bit 2 to see if size is at least 4
     test    bsize, 4
-    jz      Bit_2_Not_Set
+    jz      RDRAND_Bit_2_Not_Set
 
     mov     DWORD PTR [buffer], eax
     shr     rax, 32
     add     buffer, 4
 
-Bit_2_Not_Set:
+RDRAND_Bit_2_Not_Set:
 
             ;; Test bit 1 to see if size is at least 2
     test    bsize, 2
-    jz      Bit_1_Not_Set
+    jz      RDRAND_Bit_1_Not_Set
 
     mov     WORD PTR [buffer], ax
     shr     eax, 16
     add     buffer, 2
 
-Bit_1_Not_Set:
+RDRAND_Bit_1_Not_Set:
 
             ;; Test bit 0 to see if size is at least 1
     test    bsize, 1
-    jz      Bit_0_Not_Set
+    jz      RDRAND_Bit_0_Not_Set
 
     mov     BYTE PTR [buffer], al
+    ;; shr     ax, 8
+    ;; add     buffer, 1
 
-Bit_0_Not_Set:
+RDRAND_Bit_0_Not_Set:
 
             ;; We've hit all the bits
 
-GenerateBlock_Return:
+RDRAND_GenerateBlock_Return:
 
             ;; Clear artifacts
     xor     rax, rax
     ret
 
-MASM_RDSEED_GenerateBlock ENDP
+MASM_RDRAND_GenerateBlock ENDP
 
 ENDIF    ;; _M_X64
 
-OPTION PROLOGUE:PrologueDef
-OPTION EPILOGUE:EpilogueDef
-
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
diff --git a/src/Crypto/rdseed_ml.asm b/src/Crypto/rdseed_ml.asm
new file mode 100644
index 00000000..60704230
--- /dev/null
+++ b/src/Crypto/rdseed_ml.asm
@@ -0,0 +1,230 @@
+;; rdrand.asm - written and placed in public domain by Jeffrey Walton and Uri Blumenthal.
+;;              Copyright assigned to the Crypto++ project.
+
+;; This ASM file provides RDSEED to downlevel Microsoft tool chains.
+;; Everything "just works" under Visual Studio. Other platforms will
+;; have to run MASM/MASM-64 and then link to the object files.
+
+;; set ASFLAGS=/nologo /D_M_X86 /W3 /Cx /Zi /safeseh
+;; set ASFLAGS64=/nologo /D_M_X64 /W3 /Cx /Zi
+;; "C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin\ml.exe" %ASFLAGS% /Fo rdrand-x86.obj /c rdrand.asm
+;; "C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin\amd64\ml64.exe" %ASFLAGS64% /Fo rdrand-x64.obj /c rdrand.asm
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+TITLE    MASM_RDSEED_GenerateBlock source file
+SUBTITLE Microsoft specific ASM code to utilize RDSEED for down level Microsoft toolchains
+
+PUBLIC MASM_RDSEED_GenerateBlock
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+;; C/C++ Function prototypes (both are fastcall)
+;;   X86:
+;;      extern "C" void __fastcall MASM_RDSEED_GenerateBlock(byte* ptr, size_t size);
+;;   X64:
+;;      extern "C" void __fastcall MASM_RDSEED_GenerateBlock(byte* ptr, size_t size);
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+IFDEF _M_X86    ;; Set via the command line
+
+.486
+.MODEL FLAT
+
+;; Fastcall calling conventions exports
+ALIAS <@MASM_RDSEED_GenerateBlock@8> = <MASM_RDSEED_GenerateBlock>
+
+ENDIF
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+IFDEF _M_X86    ;; Set via the command line
+
+.CODE
+ALIGN   8
+OPTION PROLOGUE:NONE
+OPTION EPILOGUE:NONE
+
+;; No need for Load_Arguments due to fastcall
+;;   ECX (in): arg1, byte* buffer
+;;   EDX (in): arg2, size_t bsize
+
+MASM_RDSEED_GenerateBlock PROC   ;; arg1:DWORD, arg2:DWORD
+
+    MWSIZE EQU 04h    ;; machine word size
+    buffer EQU ecx
+    bsize  EQU edx
+
+            ;; Top of While loop
+RDSEED_GenerateBlock_Top:
+
+            ;; Check remaining size
+    cmp     bsize, 0
+    je      RDSEED_GenerateBlock_Return
+
+RDSEED_Call_EAX:
+            ;; RDSEED is not available prior to VS2012. Just emit
+            ;;   the byte codes using DB. This is `rdseed eax`.
+    DB      0Fh, 0C7h, 0F8h
+
+            ;; If CF=1, the number returned by RDSEED is valid.
+            ;; If CF=0, a random number was not available.
+
+            ;; Retry immediately
+    jnc     RDSEED_Call_EAX
+
+RDSEED_succeeded:
+
+    cmp     bsize, MWSIZE
+    jb      RDSEED_Partial_Machine_Word
+
+RDSEED_Full_Machine_Word:
+
+    mov     DWORD PTR [buffer], eax
+    add     buffer, MWSIZE        ;; No need for Intel Core 2 slow workarounds, like
+    sub     bsize, MWSIZE         ;;   `lea buffer,[buffer+MWSIZE]` for faster adds
+
+            ;; Continue
+    jmp     RDSEED_GenerateBlock_Top
+
+            ;; 1,2,3 bytes remain
+RDSEED_Partial_Machine_Word:
+
+            ;; Test bit 1 to see if size is at least 2
+    test    bsize, 2
+    jz      RDSEED_Bit_1_Not_Set
+
+    mov     WORD PTR [buffer], ax
+    shr     eax, 16
+    add     buffer, 2
+
+RDSEED_Bit_1_Not_Set:
+
+            ;; Test bit 0 to see if size is at least 1
+    test    bsize, 1
+    jz      RDSEED_Bit_0_Not_Set
+
+    mov     BYTE PTR [buffer], al
+    ;; shr     ax, 8
+    ;; add     buffer, 1
+
+RDSEED_Bit_0_Not_Set:
+
+            ;; We've hit all the bits
+
+RDSEED_GenerateBlock_Return:
+
+            ;; Clear artifacts
+    xor     eax, eax
+    ret
+
+MASM_RDSEED_GenerateBlock ENDP
+
+ENDIF    ;; _M_X86
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+IFDEF _M_X64    ;; Set via the command line
+
+.CODE
+ALIGN   16
+OPTION PROLOGUE:NONE
+OPTION EPILOGUE:NONE
+
+;; No need for Load_Arguments due to fastcall
+;;   RCX (in): arg1, byte* buffer
+;;   RDX (in): arg2, size_t bsize
+
+MASM_RDSEED_GenerateBlock PROC   ;; arg1:QWORD, arg2:QWORD
+
+    MWSIZE EQU 08h    ;; machine word size
+    buffer EQU rcx
+    bsize  EQU rdx
+
+            ;; Top of While loop
+RDSEED_GenerateBlock_Top:
+
+            ;; Check remaining size
+    cmp     bsize, 0
+    je      RDSEED_GenerateBlock_Return
+
+RDSEED_Call_RAX:
+            ;; RDSEED is not available prior to VS2012. Just emit
+            ;;   the byte codes using DB. This is `rdseed rax`.
+    DB      048h, 0Fh, 0C7h, 0F8h
+
+            ;; If CF=1, the number returned by RDSEED is valid.
+            ;; If CF=0, a random number was not available.
+
+            ;; Retry immediately
+    jnc     RDSEED_Call_RAX
+
+RDSEED_succeeded:
+
+    cmp     bsize, MWSIZE
+    jb      RDSEED_Partial_Machine_Word
+
+RDSEED_Full_Machine_Word:
+
+    mov     QWORD PTR [buffer], rax
+    add     buffer, MWSIZE
+    sub     bsize, MWSIZE
+
+            ;; Continue
+    jmp     RDSEED_GenerateBlock_Top
+
+            ;; 1,2,3,4,5,6,7 bytes remain
+RDSEED_Partial_Machine_Word:
+
+            ;; Test bit 2 to see if size is at least 4
+    test    bsize, 4
+    jz      RDSEED_Bit_2_Not_Set
+
+    mov     DWORD PTR [buffer], eax
+    shr     rax, 32
+    add     buffer, 4
+
+RDSEED_Bit_2_Not_Set:
+
+            ;; Test bit 1 to see if size is at least 2
+    test    bsize, 2
+    jz      RDSEED_Bit_1_Not_Set
+
+    mov     WORD PTR [buffer], ax
+    shr     eax, 16
+    add     buffer, 2
+
+RDSEED_Bit_1_Not_Set:
+
+            ;; Test bit 0 to see if size is at least 1
+    test    bsize, 1
+    jz      RDSEED_Bit_0_Not_Set
+
+    mov     BYTE PTR [buffer], al
+    ;; shr     ax, 8
+    ;; add     buffer, 1
+
+RDSEED_Bit_0_Not_Set:
+
+            ;; We've hit all the bits
+
+RDSEED_GenerateBlock_Return:
+
+            ;; Clear artifacts
+    xor     rax, rax
+    ret
+
+MASM_RDSEED_GenerateBlock ENDP
+
+ENDIF    ;; _M_X64
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+END
author	Mounir IDRASSI <mounir.idrassi@idrix.fr>	2019-10-30 00:15:28 +0100
committer	Mounir IDRASSI <mounir.idrassi@idrix.fr>	2019-10-30 08:52:55 +0100
commit	7a35ecb154fc979d46dea8d97d0ad97fd4ae4140 (patch)
tree	185a5ed69b1fd7cdde2d3b0e68841e76e1c13d8b /src/Crypto
parent	3b5d4771a0af5b4fc89ec77f43826b9ae2544949 (diff)
download	VeraCrypt-7a35ecb154fc979d46dea8d97d0ad97fd4ae4140.tar.gz VeraCrypt-7a35ecb154fc979d46dea8d97d0ad97fd4ae4140.zip