The commit adds check in function InternalPrintGraphic() to ensure that
the expression:

Blt->Width * Blt->Height * sizeof (EFI_GRAPHICS_OUTPUT_BLT_PIXEL)

will not overflow in the UINTN range.

The commit also adds an explicit UINT32 type cast for 'Blt->Width' to
avoid possible overflow in the int range for:

Blt->Width * Blt->Height

Since both Blt->Width and Blt->Height are of type UINT16. They will be
promoted to int (signed) first, and then perform the multiplication
operation. If the result of multiplication between Blt->Width and
Blt->Height exceeds the range of type int, a potential incorrect size will
be passed into funciton AllocateZeroPool().

Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
---
 MdePkg/Library/UefiLib/UefiLibPrint.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/MdePkg/Library/UefiLib/UefiLibPrint.c b/MdePkg/Library/UefiLib/UefiLibPrint.c
index 9f52e7d0ce..5527f8e7a8 100644
--- a/MdePkg/Library/UefiLib/UefiLibPrint.c
+++ b/MdePkg/Library/UefiLib/UefiLibPrint.c
@@ -2,7 +2,7 @@
   Mde UEFI library API implementation.
   Print to StdErr or ConOut defined in EFI_SYSTEM_TABLE
 
-  Copyright (c) 2007 - 2015, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2007 - 2017, Intel Corporation. All rights reserved.<BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
@@ -474,7 +474,14 @@ InternalPrintGraphic (
   } else if (FeaturePcdGet (PcdUgaConsumeSupport)) {
     ASSERT (UgaDraw!= NULL);
 
-    Blt->Image.Bitmap = AllocateZeroPool (Blt->Width * Blt->Height * sizeof (EFI_GRAPHICS_OUTPUT_BLT_PIXEL));
+    //
+    // Ensure Width * Height * sizeof (EFI_GRAPHICS_OUTPUT_BLT_PIXEL) doesn't overflow.
+    //
+    if (Blt->Width > DivU64x32 (MAX_UINTN, Blt->Height * sizeof (EFI_GRAPHICS_OUTPUT_BLT_PIXEL))) {
+      goto Error;
+    }
+
+    Blt->Image.Bitmap = AllocateZeroPool ((UINT32) Blt->Width * Blt->Height * sizeof (EFI_GRAPHICS_OUTPUT_BLT_PIXEL));
     ASSERT (Blt->Image.Bitmap != NULL);
 
     //
-- 
2.12.0.windows.1

_______________________________________________
edk2-devel mailing list
edk2-devel@lists.01.org
https://lists.01.org/mailman/listinfo/edk2-devel

Reviewed-by: Liming Gao <liming.gao@intel.com>

>-----Original Message-----
>From: Wu, Hao A
>Sent: Tuesday, April 11, 2017 10:17 AM
>To: edk2-devel@lists.01.org
>Cc: Wu, Hao A <hao.a.wu@intel.com>; Gao, Liming <liming.gao@intel.com>
>Subject: [PATCH 1/2] MdePkg/UefiLib: Avoid mis-calculate of graphic console
>size
>
>The commit adds check in function InternalPrintGraphic() to ensure that
>the expression:
>
>Blt->Width * Blt->Height * sizeof (EFI_GRAPHICS_OUTPUT_BLT_PIXEL)
>
>will not overflow in the UINTN range.
>
>The commit also adds an explicit UINT32 type cast for 'Blt->Width' to
>avoid possible overflow in the int range for:
>
>Blt->Width * Blt->Height
>
>Since both Blt->Width and Blt->Height are of type UINT16. They will be
>promoted to int (signed) first, and then perform the multiplication
>operation. If the result of multiplication between Blt->Width and
>Blt->Height exceeds the range of type int, a potential incorrect size will
>be passed into funciton AllocateZeroPool().
>
>Cc: Liming Gao <liming.gao@intel.com>
>Contributed-under: TianoCore Contribution Agreement 1.0
>Signed-off-by: Hao Wu <hao.a.wu@intel.com>
>---
> MdePkg/Library/UefiLib/UefiLibPrint.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
>diff --git a/MdePkg/Library/UefiLib/UefiLibPrint.c
>b/MdePkg/Library/UefiLib/UefiLibPrint.c
>index 9f52e7d0ce..5527f8e7a8 100644
>--- a/MdePkg/Library/UefiLib/UefiLibPrint.c
>+++ b/MdePkg/Library/UefiLib/UefiLibPrint.c
>@@ -2,7 +2,7 @@
>   Mde UEFI library API implementation.
>   Print to StdErr or ConOut defined in EFI_SYSTEM_TABLE
>
>-  Copyright (c) 2007 - 2015, Intel Corporation. All rights reserved.<BR>
>+  Copyright (c) 2007 - 2017, Intel Corporation. All rights reserved.<BR>
>   This program and the accompanying materials
>   are licensed and made available under the terms and conditions of the BSD
>License
>   which accompanies this distribution.  The full text of the license may be
>found at
>@@ -474,7 +474,14 @@ InternalPrintGraphic (
>   } else if (FeaturePcdGet (PcdUgaConsumeSupport)) {
>     ASSERT (UgaDraw!= NULL);
>
>-    Blt->Image.Bitmap = AllocateZeroPool (Blt->Width * Blt->Height * sizeof
>(EFI_GRAPHICS_OUTPUT_BLT_PIXEL));
>+    //
>+    // Ensure Width * Height * sizeof (EFI_GRAPHICS_OUTPUT_BLT_PIXEL)
>doesn't overflow.
>+    //
>+    if (Blt->Width > DivU64x32 (MAX_UINTN, Blt->Height * sizeof
>(EFI_GRAPHICS_OUTPUT_BLT_PIXEL))) {
>+      goto Error;
>+    }
>+
>+    Blt->Image.Bitmap = AllocateZeroPool ((UINT32) Blt->Width * Blt->Height
>* sizeof (EFI_GRAPHICS_OUTPUT_BLT_PIXEL));
>     ASSERT (Blt->Image.Bitmap != NULL);
>
>     //
>--
>2.12.0.windows.1

_______________________________________________
edk2-devel mailing list
edk2-devel@lists.01.org
https://lists.01.org/mailman/listinfo/edk2-devel