SecurityPkg: Refine type cast for pointer subtraction

For pointer subtraction, the result is of type "ptrdiff_t". According to
the C11 standard (Committee Draft - April 12, 2011):

"When two pointers are subtracted, both shall point to elements of the
same array object, or one past the last element of the array object; the
result is the difference of the subscripts of the two array elements. The
size of the result is implementation-defined, and its type (a signed
integer type) is ptrdiff_t defined in the <stddef.h> header. If the result
is not representable in an object of that type, the behavior is
undefined."

In our codes, there are cases that the pointer subtraction is not
performed by pointers to elements of the same array object. This might
lead to potential issues, since the behavior is undefined according to C11
standard.

Also, since the size of type "ptrdiff_t" is implementation-defined. Some
static code checkers may warn that the pointer subtraction might underflow
first and then being cast to a bigger size. For example:

UINT8  *Ptr1, *Ptr2;
UINTN  PtrDiff;
...
PtrDiff = (UINTN) (Ptr1 - Ptr2);

The commit will refine the pointer subtraction expressions by casting each
pointer to UINTN first and then perform the subtraction:

PtrDiff = (UINTN) Ptr1 - (UINTN) Ptr2;

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Chao Zhang <chao.b.zhang@intel.com>

diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index e28e10641a57f90fcbc7f6f70d31a448f9d59abf..588072c6a1d8ca4184b7f14928e722ccaa0a838a 100644 (file)
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -391,13 +391,13 @@ HashPeImage (
     //\r
     // Use PE32 offset.\r
     //\r
-    HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32->OptionalHeader.CheckSum) - HashBase);\r
+    HashSize = (UINTN) (&mNtHeader.Pe32->OptionalHeader.CheckSum) - (UINTN) HashBase;\r
     NumberOfRvaAndSizes = mNtHeader.Pe32->OptionalHeader.NumberOfRvaAndSizes;\r
   } else if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC) {\r
     //\r
     // Use PE32+ offset.\r
     //\r
-    HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32Plus->OptionalHeader.CheckSum) - HashBase);\r
+    HashSize = (UINTN) (&mNtHeader.Pe32Plus->OptionalHeader.CheckSum) - (UINTN) HashBase;\r
     NumberOfRvaAndSizes = mNtHeader.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;\r
   } else {\r
     //\r
@@ -425,13 +425,13 @@ HashPeImage (
       // Use PE32 offset.\r
       //\r
       HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);\r
-      HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - (UINTN) (HashBase - mImageBase);\r
+      HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);\r
     } else {\r
       //\r
       // Use PE32+ offset.\r
       //\r
       HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);\r
-      HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - (UINTN) (HashBase - mImageBase);\r
+      HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);\r
     }\r
 \r
     if (HashSize != 0) {\r
@@ -449,13 +449,13 @@ HashPeImage (
       // Use PE32 offset.\r
       //\r
       HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);\r
-      HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);\r
+      HashSize = (UINTN) (&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;\r
     } else {\r
       //\r
       // Use PE32+ offset.\r
       //\r
       HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);\r
-      HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);\r
+      HashSize = (UINTN) (&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;\r
     }\r
 \r
     if (HashSize != 0) {\r
@@ -474,13 +474,13 @@ HashPeImage (
       // Use PE32 offset\r
       //\r
       HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];\r
-      HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - (UINTN) (HashBase - mImageBase);\r
+      HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);\r
     } else {\r
       //\r
       // Use PE32+ offset.\r
       //\r
       HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];\r
-      HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - (UINTN) (HashBase - mImageBase);\r
+      HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - ((UINTN) HashBase - (UINTN) mImageBase);\r
     }\r
 \r
     if (HashSize != 0) {\r

diff --git a/SecurityPkg/Library/DxeTpmMeasureBootLib/DxeTpmMeasureBootLib.c b/SecurityPkg/Library/DxeTpmMeasureBootLib/DxeTpmMeasureBootLib.c
index 52bf582d82e033fcdc5aa138e2209cff4e80fa84..8167a21929097353856ce05736301f8a45502330 100644 (file)
--- a/SecurityPkg/Library/DxeTpmMeasureBootLib/DxeTpmMeasureBootLib.c
+++ b/SecurityPkg/Library/DxeTpmMeasureBootLib/DxeTpmMeasureBootLib.c
@@ -15,7 +15,7 @@
   TcgMeasureGptTable() function will receive untrusted GPT partition table, and parse\r
   partition data carefully.\r
 \r
-Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.<BR>\r
+Copyright (c) 2009 - 2017, Intel Corporation. All rights reserved.<BR>\r
 This program and the accompanying materials \r
 are licensed and made available under the terms and conditions of the BSD License \r
 which accompanies this distribution.  The full text of the license may be found at \r
@@ -443,13 +443,13 @@ TcgMeasurePeImage (
     // Use PE32 offset\r
     //\r
     NumberOfRvaAndSizes = Hdr.Pe32->OptionalHeader.NumberOfRvaAndSizes;\r
-    HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32->OptionalHeader.CheckSum) - HashBase);\r
+    HashSize = (UINTN) (&Hdr.Pe32->OptionalHeader.CheckSum) - (UINTN) HashBase;\r
   } else {\r
     //\r
     // Use PE32+ offset\r
     //\r
     NumberOfRvaAndSizes = Hdr.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;\r
-    HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32Plus->OptionalHeader.CheckSum) - HashBase);\r
+    HashSize = (UINTN) (&Hdr.Pe32Plus->OptionalHeader.CheckSum) - (UINTN) HashBase;\r
   }\r
 \r
   HashStatus = Sha1Update (Sha1Ctx, HashBase, HashSize);\r
@@ -494,13 +494,13 @@ TcgMeasurePeImage (
       // Use PE32 offset\r
       //\r
       HashBase = (UINT8 *) &Hdr.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);\r
-      HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);\r
+      HashSize = (UINTN) (&Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;\r
     } else {\r
       //\r
       // Use PE32+ offset\r
       //    \r
       HashBase = (UINT8 *) &Hdr.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);\r
-      HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);\r
+      HashSize = (UINTN) (&Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;\r
     }\r
 \r
     if (HashSize != 0) {\r

diff --git a/SecurityPkg/Library/Tpm2CommandLib/Tpm2Help.c b/SecurityPkg/Library/Tpm2CommandLib/Tpm2Help.c
index 64d3c531ff92247af2bf4169ba93abfc38112519..180f36083096f86e76011bb195e0aa9c89fb8387 100644 (file)
--- a/SecurityPkg/Library/Tpm2CommandLib/Tpm2Help.c
+++ b/SecurityPkg/Library/Tpm2CommandLib/Tpm2Help.c
@@ -1,7 +1,7 @@
 /** @file\r
   Implement TPM2 help.\r
 \r
-Copyright (c) 2013 - 2016, Intel Corporation. All rights reserved. <BR>\r
+Copyright (c) 2013 - 2017, Intel Corporation. All rights reserved. <BR>\r
 This program and the accompanying materials\r
 are licensed and made available under the terms and conditions of the BSD License\r
 which accompanies this distribution.  The full text of the license may be found at\r
@@ -141,7 +141,7 @@ CopyAuthSessionCommand (
     Buffer += sizeof(UINT16);\r
   }\r
 \r
-  return (UINT32)(UINTN)(Buffer - (UINT8 *)AuthSessionOut);\r
+  return (UINT32)((UINTN)Buffer - (UINTN)AuthSessionOut);\r
 }\r
 \r
 /**\r
@@ -186,7 +186,7 @@ CopyAuthSessionResponse (
   CopyMem (AuthSessionOut->hmac.buffer, Buffer, AuthSessionOut->hmac.size);\r
   Buffer += AuthSessionOut->hmac.size;\r
 \r
-  return (UINT32)(UINTN)(Buffer - (UINT8 *)AuthSessionIn);\r
+  return (UINT32)((UINTN)Buffer - (UINTN)AuthSessionIn);\r
 }\r
 \r
 /**\r

diff --git a/SecurityPkg/Tcg/Tcg2Dxe/MeasureBootPeCoff.c b/SecurityPkg/Tcg/Tcg2Dxe/MeasureBootPeCoff.c
index de55ed9923b6225efa77b2fe1bb5eafe6ef8f5ac..8ee34a702ecb02456ff8805389c8cd2bac7f3a31 100644 (file)
--- a/SecurityPkg/Tcg/Tcg2Dxe/MeasureBootPeCoff.c
+++ b/SecurityPkg/Tcg/Tcg2Dxe/MeasureBootPeCoff.c
@@ -6,7 +6,7 @@
   This external input must be validated carefully to avoid security issue like\r
   buffer overflow, integer overflow.\r
 \r
-Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>\r
+Copyright (c) 2015 - 2017, Intel Corporation. All rights reserved.<BR>\r
 This program and the accompanying materials \r
 are licensed and made available under the terms and conditions of the BSD License \r
 which accompanies this distribution.  The full text of the license may be found at \r
@@ -206,13 +206,13 @@ MeasurePeImageAndExtend (
     // Use PE32 offset\r
     //\r
     NumberOfRvaAndSizes = Hdr.Pe32->OptionalHeader.NumberOfRvaAndSizes;\r
-    HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32->OptionalHeader.CheckSum) - HashBase);\r
+    HashSize = (UINTN) (&Hdr.Pe32->OptionalHeader.CheckSum) - (UINTN) HashBase;\r
   } else {\r
     //\r
     // Use PE32+ offset\r
     //\r
     NumberOfRvaAndSizes = Hdr.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;\r
-    HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32Plus->OptionalHeader.CheckSum) - HashBase);\r
+    HashSize = (UINTN) (&Hdr.Pe32Plus->OptionalHeader.CheckSum) - (UINTN) HashBase;\r
   }\r
 \r
   Status = HashUpdate (HashHandle, HashBase, HashSize);\r
@@ -257,13 +257,13 @@ MeasurePeImageAndExtend (
       // Use PE32 offset\r
       //\r
       HashBase = (UINT8 *) &Hdr.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);\r
-      HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);\r
+      HashSize = (UINTN) (&Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;\r
     } else {\r
       //\r
       // Use PE32+ offset\r
       //    \r
       HashBase = (UINT8 *) &Hdr.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);\r
-      HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);\r
+      HashSize = (UINTN) (&Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;\r
     }\r
 \r
     if (HashSize != 0) {\r

diff --git a/SecurityPkg/Tcg/TrEEDxe/MeasureBootPeCoff.c b/SecurityPkg/Tcg/TrEEDxe/MeasureBootPeCoff.c
index b20fc70ee0a4b76a01accbdd1598b715b31f7b22..a7de5883ccc5f5864be5bd5214122cf3b648759d 100644 (file)
--- a/SecurityPkg/Tcg/TrEEDxe/MeasureBootPeCoff.c
+++ b/SecurityPkg/Tcg/TrEEDxe/MeasureBootPeCoff.c
@@ -6,7 +6,7 @@
   This external input must be validated carefully to avoid security issue like\r
   buffer overflow, integer overflow.\r
 \r
-Copyright (c) 2013 - 2016, Intel Corporation. All rights reserved.<BR>\r
+Copyright (c) 2013 - 2017, Intel Corporation. All rights reserved.<BR>\r
 This program and the accompanying materials \r
 are licensed and made available under the terms and conditions of the BSD License \r
 which accompanies this distribution.  The full text of the license may be found at \r
@@ -206,13 +206,13 @@ MeasurePeImageAndExtend (
     // Use PE32 offset\r
     //\r
     NumberOfRvaAndSizes = Hdr.Pe32->OptionalHeader.NumberOfRvaAndSizes;\r
-    HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32->OptionalHeader.CheckSum) - HashBase);\r
+    HashSize = (UINTN) (&Hdr.Pe32->OptionalHeader.CheckSum) - (UINTN) HashBase;\r
   } else {\r
     //\r
     // Use PE32+ offset\r
     //\r
     NumberOfRvaAndSizes = Hdr.Pe32Plus->OptionalHeader.NumberOfRvaAndSizes;\r
-    HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32Plus->OptionalHeader.CheckSum) - HashBase);\r
+    HashSize = (UINTN) (&Hdr.Pe32Plus->OptionalHeader.CheckSum) - (UINTN) HashBase;\r
   }\r
 \r
   Status = HashUpdate (HashHandle, HashBase, HashSize);\r
@@ -257,13 +257,13 @@ MeasurePeImageAndExtend (
       // Use PE32 offset\r
       //\r
       HashBase = (UINT8 *) &Hdr.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);\r
-      HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);\r
+      HashSize = (UINTN) (&Hdr.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;\r
     } else {\r
       //\r
       // Use PE32+ offset\r
       //    \r
       HashBase = (UINT8 *) &Hdr.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);\r
-      HashSize = (UINTN) ((UINT8 *)(&Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);\r
+      HashSize = (UINTN) (&Hdr.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;\r
     }\r
 \r
     if (HashSize != 0) {\r

diff --git a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c
index 16ca9578ba0e3b201b2938bfa5df06827e695b81..3ce48140cf388ae649396b4eb118342f66a4cbe5 100644 (file)
--- a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c
+++ b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c
@@ -1837,12 +1837,12 @@ HashPeImage (
     //\r
     // Use PE32 offset.\r
     //\r
-    HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32->OptionalHeader.CheckSum) - HashBase);\r
+    HashSize = (UINTN) (&mNtHeader.Pe32->OptionalHeader.CheckSum) - (UINTN) HashBase;\r
   } else {\r
     //\r
     // Use PE32+ offset.\r
     //\r
-    HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32Plus->OptionalHeader.CheckSum) - HashBase);\r
+    HashSize = (UINTN) (&mNtHeader.Pe32Plus->OptionalHeader.CheckSum) - (UINTN) HashBase;\r
   }\r
 \r
   Status  = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);\r
@@ -1859,13 +1859,13 @@ HashPeImage (
     // Use PE32 offset.\r
     //\r
     HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);\r
-    HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);\r
+    HashSize = (UINTN) (&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;\r
   } else {\r
     //\r
     // Use PE32+ offset.\r
     //\r
     HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);\r
-    HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);\r
+    HashSize = (UINTN) (&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - (UINTN) HashBase;\r
   }\r
 \r
   Status  = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);\r
@@ -1881,13 +1881,13 @@ HashPeImage (
     // Use PE32 offset\r
     //\r
     HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];\r
-    HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - (UINTN) ((UINT8 *) (&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1]) - mImageBase);\r
+    HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - ((UINTN) (&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1]) - (UINTN) mImageBase);\r
   } else {\r
     //\r
     // Use PE32+ offset.\r
     //\r
     HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];\r
-    HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - (UINTN) ((UINT8 *) (&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1]) - mImageBase);\r
+    HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - ((UINTN) (&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1]) - (UINTN) mImageBase);\r
   }\r
 \r
   Status  = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);\r