From 6e3079460fa075f4b44c1031b1e20709979d9424 Mon Sep 17 00:00:00 2001

From: Philippe Mathieu-Daude <philmd@redhat.com>

Date: Wed, 13 Feb 2019 09:50:45 +0100

Subject: [PATCH 02/13] MdePkg: Add more checker in UefiDecompressLib to access

 the valid buffer only (CVE FIX)

Message-id: <20190213085050.20766-3-philmd@redhat.com>

Patchwork-id: 84480

O-Subject:  [RHEL-7.7 ovmf PATCH v3 2/7] MdePkg: Add more checker in

	UefiDecompressLib to access the valid buffer only (CVE FIX)

Bugzilla: 1666586

Acked-by: Laszlo Ersek <lersek@redhat.com>

Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>

From: Laszlo Ersek <lersek@redhat.com>

From: Liming Gao <liming.gao@intel.com>

--v-- RHEL7 note start --v--

Unfortunately, the upstream patch series was not structured according to

the CVE reports. This patch contributes to fixing:

- CVE-2017-5732

- CVE-2017-5733

- CVE-2017-5734

- CVE-2017-5735

but not CVE-2017-5731 (contrarily to the upstream commit message). The

best I could achieve up-stream was to get the "CVE FIX" expression into

the subject, and a whole-sale dump of the CVEs into the body. I had not

been invited to the original (off-list, embargoed) analysis and review.

The trivial context difference (whitespace) is due to RHEL8 lacking

upstream commit 9095d37b8fe5 ("MdePkg: Clean up source files",

2018-06-28). I've considered backporting that (since it only cleans up

whitespace). However, the diffstat on that commit convinced me otherwise:

"729 files changed, 15667 insertions(+), 15667 deletions(-)". I've decided

not to do a partial backport of that (i.e. just for

"BaseUefiDecompressLib.c").

--^-- RHEL7 note end --^--

Fix CVE-2017-5731,CVE-2017-5732,CVE-2017-5733,CVE-2017-5734,CVE-2017-5735

https://bugzilla.tianocore.org/show_bug.cgi?id=686

Contributed-under: TianoCore Contribution Agreement 1.1

Signed-off-by: Holtsclaw Brent <brent.holtsclaw@intel.com>

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

Reviewed-by: Star Zeng <star.zeng@intel.com>

Acked-by: Laszlo Ersek <lersek@redhat.com>

(cherry picked from commit 2ec7953d49677142c5f7552e9e3d96fb406ba0c4)

Signed-off-by: Laszlo Ersek <lersek@redhat.com>

(cherry picked from commit 41129e136b621728eb5cb1c81aafcc5fedc53a12)

Signed-off-by: Philippe Mathieu-Daude <philmd@redhat.com>

---

 .../BaseUefiDecompressLib/BaseUefiDecompressLib.c       | 17 +++++++++++++++--

 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c b/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c

index e818543..0c6b1fe 100644

--- a/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c

+++ b/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c

@@ -152,6 +152,7 @@ MakeTable (

   UINT16  Mask;

   UINT16  WordOfStart;

   UINT16  WordOfCount;

+  UINT16  MaxTableLength;

   //

   // The maximum mapping table width supported by this internal

@@ -164,6 +165,9 @@ MakeTable (

   }

   for (Index = 0; Index < NumOfChar; Index++) {

+    if (BitLen[Index] > 16) {

+      return (UINT16) BAD_TABLE;

+    }

     Count[BitLen[Index]]++;

   }

@@ -205,6 +209,7 @@ MakeTable (

   Avail = NumOfChar;

   Mask  = (UINT16) (1U << (15 - TableBits));

+  MaxTableLength = (UINT16) (1U << TableBits);

   for (Char = 0; Char < NumOfChar; Char++) {

@@ -218,6 +223,9 @@ MakeTable (

     if (Len <= TableBits) {

       for (Index = Start[Len]; Index < NextCode; Index++) {

+        if (Index >= MaxTableLength) {

+          return (UINT16) BAD_TABLE;

+        }

         Table[Index] = Char;

       }

@@ -620,11 +628,16 @@ Decode (

       // Write BytesRemain of bytes into mDstBase

       //

       BytesRemain--;

+

       while ((INT16) (BytesRemain) >= 0) {

-        Sd->mDstBase[Sd->mOutBuf++] = Sd->mDstBase[DataIdx++];

         if (Sd->mOutBuf >= Sd->mOrigSize) {

           goto Done;

         }

+        if (DataIdx >= Sd->mOrigSize) {

+          Sd->mBadTableFlag = (UINT16) BAD_TABLE;

+          goto Done;

+        }

+        Sd->mDstBase[Sd->mOutBuf++] = Sd->mDstBase[DataIdx++];

         BytesRemain--;

       }

@@ -694,7 +707,7 @@ UefiDecompressGetInfo (

   }

   CompressedSize   = ReadUnaligned32 ((UINT32 *)Source);

-  if (SourceSize < (CompressedSize + 8)) {

+  if (SourceSize < (CompressedSize + 8) || (CompressedSize + 8) < 8) {

     return RETURN_INVALID_PARAMETER;

   }

-- 

1.8.3.1