From e7bd0dd26db7e56aa8ca70132d6ea916ee6f3db0 Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Thu, 19 Nov 2020 12:50:34 +0100
Subject: [PATCH] MdeModulePkg/LzmaCustomDecompressLib: catch 4GB+ uncompressed
 buffer sizes
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The LzmaUefiDecompressGetInfo() function
[MdeModulePkg/Library/LzmaCustomDecompressLib/LzmaDecompress.c] currently
silently truncates the UINT64 "DecodedSize" property of the compressed
blob to the UINT32 "DestinationSize" output parameter.

If "DecodedSize" is 0x1_0000_0100, for example, then the subsequent memory
allocation (for decompression) will likely succeed (allocating 0x100 bytes
only), but then the LzmaUefiDecompress() function (which re-fetches the
uncompressed buffer size from the same LZMA header into a "SizeT"
variable) will overwrite the buffer.

Catch (DecodedSize > MAX_UINT32) in LzmaUefiDecompressGetInfo() at once.
This should not be a practical limitation. (The issue cannot be fixed for
32-bit systems without spec modifications anyway, given that the
"OutputSize" output parameter of
EFI_GUIDED_SECTION_EXTRACTION_PROTOCOL.ExtractSection() has type UINTN,
not UINT64.)

Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1816
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20201119115034.12897-2-lersek@redhat.com>
---
 .../Library/LzmaCustomDecompressLib/LzmaDecompress.c       | 7 +++++++
 .../LzmaCustomDecompressLib/LzmaDecompressLibInternal.h    | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/MdeModulePkg/Library/LzmaCustomDecompressLib/LzmaDecompress.c b/MdeModulePkg/Library/LzmaCustomDecompressLib/LzmaDecompress.c
index c58912eb6a..8f7c242dca 100644
--- a/MdeModulePkg/Library/LzmaCustomDecompressLib/LzmaDecompress.c
+++ b/MdeModulePkg/Library/LzmaCustomDecompressLib/LzmaDecompress.c
@@ -127,6 +127,10 @@ GetDecodedSizeOfBuf(
                           in DestinationSize and the size of the scratch
                           buffer was returned in ScratchSize.
 
+  @retval RETURN_UNSUPPORTED  DestinationSize cannot be output because the
+                              uncompressed buffer size (in bytes) does not fit
+                              in a UINT32. Output parameters have not been
+                              modified.
 **/
 RETURN_STATUS
 EFIAPI
@@ -142,6 +146,9 @@ LzmaUefiDecompressGetInfo (
   ASSERT(SourceSize >= LZMA_HEADER_SIZE);
 
   DecodedSize = GetDecodedSizeOfBuf((UINT8*)Source);
+  if (DecodedSize > MAX_UINT32) {
+    return RETURN_UNSUPPORTED;
+  }
 
   *DestinationSize = (UINT32)DecodedSize;
   *ScratchSize = SCRATCH_BUFFER_REQUEST_SIZE;
diff --git a/MdeModulePkg/Library/LzmaCustomDecompressLib/LzmaDecompressLibInternal.h b/MdeModulePkg/Library/LzmaCustomDecompressLib/LzmaDecompressLibInternal.h
index 26f110ba2a..fbafd5f100 100644
--- a/MdeModulePkg/Library/LzmaCustomDecompressLib/LzmaDecompressLibInternal.h
+++ b/MdeModulePkg/Library/LzmaCustomDecompressLib/LzmaDecompressLibInternal.h
@@ -9,6 +9,7 @@
 #ifndef __LZMADECOMPRESSLIB_INTERNAL_H__
 #define __LZMADECOMPRESSLIB_INTERNAL_H__
 
+#include <Base.h>
 #include <PiPei.h>
 #include <Library/BaseLib.h>
 #include <Library/BaseMemoryLib.h>
@@ -45,6 +46,10 @@
                           in DestinationSize and the size of the scratch
                           buffer was returned in ScratchSize.
 
+  @retval RETURN_UNSUPPORTED  DestinationSize cannot be output because the
+                              uncompressed buffer size (in bytes) does not fit
+                              in a UINT32. Output parameters have not been
+                              modified.
 **/
 RETURN_STATUS
 EFIAPI
-- 
2.27.0

