Add comment for modules which have external input.

[mirror_edk2.git] / SecurityPkg / Library / DxeImageVerificationLib / DxeImageVerificationLib.c

diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index 2a54296134b5835ed7f5645f58fd79fbf6d9a189..dff4bd037141b11d3f41eb067b3759994575f609 100644 (file)
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -1,6 +1,17 @@
 /** @file\r
   Implement image verification services for secure boot service in UEFI2.3.1.\r
 \r
+  Caution: This file requires additional review when modified.\r
+  This library will have external input - PE/COFF image.\r
+  This external input must be validated carefully to avoid security issue like\r
+  buffer overflow, integer overflow.\r
+\r
+  DxeImageVerificationLibImageRead() function will make sure the PE/COFF image content\r
+  read is within the image buffer.\r
+\r
+  DxeImageVerificationHandler(), HashPeImageByType(), HashPeImage() function will accept\r
+  untrusted PE/COFF image and validate its data structure within this image buffer before use.\r
+\r
 Copyright (c) 2009 - 2012, 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
@@ -14,15 +25,23 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 \r
 #include "DxeImageVerificationLib.h"\r
 \r
+//\r
+// Caution: This is used by a function which may receive untrusted input.\r
+// These global variables hold PE/COFF image data, and they should be validated before use.\r
+//\r
 EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION mNtHeader;\r
-UINTN                               mImageSize;\r
 UINT32                              mPeCoffHeaderOffset;\r
-UINT8                               mImageDigest[MAX_DIGEST_SIZE];\r
-UINTN                               mImageDigestSize;\r
 EFI_IMAGE_DATA_DIRECTORY            *mSecDataDir      = NULL;\r
-UINT8                               *mImageBase       = NULL;\r
 EFI_GUID                            mCertType;\r
 \r
+//\r
+// Information on current PE/COFF image\r
+//\r
+UINTN                               mImageSize;\r
+UINT8                               *mImageBase       = NULL;\r
+UINT8                               mImageDigest[MAX_DIGEST_SIZE];\r
+UINTN                               mImageDigestSize;\r
+\r
 //\r
 // Notify string for authorization UI.\r
 //\r
@@ -57,6 +76,10 @@ HASH_TABLE mHash[] = {
 /**\r
   Reads contents of a PE/COFF image in memory buffer.\r
 \r
+  Caution: This function may receive untrusted input.\r
+  PE/COFF image is external input, so this function will make sure the PE/COFF image content\r
+  read is within the image buffer.\r
+\r
   @param  FileHandle      Pointer to the file handle to read the PE/COFF image.\r
   @param  FileOffset      Offset into the PE/COFF image to begin the read operation.\r
   @param  ReadSize        On input, the size in bytes of the requested read operation.  \r
@@ -229,6 +252,10 @@ GetImageType (
   Caculate hash of Pe/Coff image based on the authenticode image hashing in\r
   PE/COFF Specification 8.0 Appendix A\r
 \r
+  Caution: This function may receive untrusted input.\r
+  PE/COFF image is external input, so this function will validate its data structure\r
+  within this image buffer before use.\r
+\r
   @param[in]    HashAlg   Hash algorithm type.\r
 \r
   @retval TRUE            Successfully hash image.\r
@@ -550,6 +577,10 @@ Done:
   Pe/Coff image based on the authenticode image hashing in PE/COFF Specification\r
   8.0 Appendix A\r
 \r
+  Caution: This function may receive untrusted input.\r
+  PE/COFF image is external input, so this function will validate its data structure\r
+  within this image buffer before use.\r
+\r
   @retval EFI_UNSUPPORTED             Hash algorithm is not supported.\r
   @retval EFI_SUCCESS                 Hash successfully.\r
 \r
@@ -1184,6 +1215,10 @@ Done:
           If no,\r
             Error out\r
 \r
+  Caution: This function may receive untrusted input.\r
+  PE/COFF image is external input, so this function will validate its data structure\r
+  within this image buffer before use.\r
+\r
   @param[in]    AuthenticationStatus\r
                            This is the authentication status returned from the security\r
                            measurement services for the input file.\r