Add patch for CVE-2018-5996

Insufficient exception handling in the method NCompress::NRar3::CDecoder::Code
of 7-Zip before 18.00 and p7zip can lead to multiple memory corruptions within
the PPMd code, allows remote attackers to cause a denial of service
(segmentation fault) or execute arbitrary code via a crafted RAR archive.

Obtained from:	Debian (link in the patch file)
MFH:		2018Q1
Security:	7a2e0063-0e4e-11e8-94c0-5453ed2e2b49

1 files changed, 211 insertions, 0 deletions

diff --git a/archivers/p7zip/files/patch-CVE-2018-5996 b/archivers/p7zip/files/patch-CVE-2018-5996
new file mode 100644
index 000000000000..c8aaba009a67
--- /dev/null
+++ b/archivers/p7zip/files/patch-CVE-2018-5996
@@ -0,0 +1,211 @@
+Obtained from: https://anonscm.debian.org/cgit/users/robert/p7zip-rar.git/tree/debian/patches/06-CVE-2018-5996.patch
+---
+From: Robert Luberda <robert@debian.org>
+Date: Sun, 28 Jan 2018 23:47:40 +0100
+Subject: CVE-2018-5996
+
+Hopefully fix Memory Corruptions via RAR PPMd (CVE-2018-5996) by
+applying a few changes from 7Zip 18.00-beta.
+
+Bug-Debian: https://bugs.debian.org/#888314
+---
+ CPP/7zip/Compress/Rar1Decoder.cpp | 13 +++++++++----
+ CPP/7zip/Compress/Rar1Decoder.h   |  1 +
+ CPP/7zip/Compress/Rar2Decoder.cpp | 10 +++++++++-
+ CPP/7zip/Compress/Rar2Decoder.h   |  1 +
+ CPP/7zip/Compress/Rar3Decoder.cpp | 23 ++++++++++++++++++++---
+ CPP/7zip/Compress/Rar3Decoder.h   |  2 ++
+ 6 files changed, 42 insertions(+), 8 deletions(-)
+
+--- CPP/7zip/Compress/Rar1Decoder.cpp
++++ CPP/7zip/Compress/Rar1Decoder.cpp
+@@ -29,7 +29,7 @@ public:
+ };
+ */
+ 
+-CDecoder::CDecoder(): m_IsSolid(false) { }
++CDecoder::CDecoder(): m_IsSolid(false), _errorMode(false) { }
+ 
+ void CDecoder::InitStructures()
+ {
+@@ -406,9 +406,14 @@ HRESULT CDecoder::CodeReal(ISequentialInStream *inStream, ISequentialOutStream *
+   InitData();
+   if (!m_IsSolid)
+   {
++    _errorMode = false;
+     InitStructures();
+     InitHuff();
+   }
++
++  if (_errorMode)
++    return S_FALSE;
++
+   if (m_UnpackSize > 0)
+   {
+     GetFlagsBuf();
+@@ -477,9 +482,9 @@ STDMETHODIMP CDecoder::Code(ISequentialInStream *inStream, ISequentialOutStream
+     const UInt64 *inSize, const UInt64 *outSize, ICompressProgressInfo *progress)
+ {
+   try { return CodeReal(inStream, outStream, inSize, outSize, progress); }
+-  catch(const CInBufferException &e) { return e.ErrorCode; }
+-  catch(const CLzOutWindowException &e) { return e.ErrorCode; }
+-  catch(...) { return S_FALSE; }
++  catch(const CInBufferException &e) { _errorMode = true; return e.ErrorCode; }
++  catch(const CLzOutWindowException &e) { _errorMode = true; return e.ErrorCode; }
++  catch(...) { _errorMode = true; return S_FALSE; }
+ }
+ 
+ STDMETHODIMP CDecoder::SetDecoderProperties2(const Byte *data, UInt32 size)
+--- CPP/7zip/Compress/Rar1Decoder.h
++++ CPP/7zip/Compress/Rar1Decoder.h
+@@ -39,6 +39,7 @@ public:
+ 
+   Int64 m_UnpackSize;
+   bool m_IsSolid;
++  bool _errorMode;
+ 
+   UInt32 ReadBits(int numBits);
+   HRESULT CopyBlock(UInt32 distance, UInt32 len);
+--- CPP/7zip/Compress/Rar2Decoder.cpp
++++ CPP/7zip/Compress/Rar2Decoder.cpp
+@@ -80,7 +80,8 @@ static const UInt32 kHistorySize = 1 << 20;
+ static const UInt32 kWindowReservSize = (1 << 22) + 256;
+ 
+ CDecoder::CDecoder():
+-  m_IsSolid(false)
++  m_IsSolid(false),
++  m_TablesOK(false)
+ {
+ }
+ 
+@@ -100,6 +101,8 @@ UInt32 CDecoder::ReadBits(unsigned numBits) { return m_InBitStream.ReadBits(numB
+ 
+ bool CDecoder::ReadTables(void)
+ {
++  m_TablesOK = false;
++
+   Byte levelLevels[kLevelTableSize];
+   Byte newLevels[kMaxTableSize];
+   m_AudioMode = (ReadBits(1) == 1);
+@@ -170,6 +173,8 @@ bool CDecoder::ReadTables(void)
+   }
+   
+   memcpy(m_LastLevels, newLevels, kMaxTableSize);
++  m_TablesOK = true;
++
+   return true;
+ }
+ 
+@@ -344,6 +349,9 @@ HRESULT CDecoder::CodeReal(ISequentialInStream *inStream, ISequentialOutStream *
+       return S_FALSE;
+   }
+ 
++  if (!m_TablesOK)
++    return S_FALSE;
++
+   UInt64 startPos = m_OutWindowStream.GetProcessedSize();
+   while (pos < unPackSize)
+   {
+--- CPP/7zip/Compress/Rar2Decoder.h
++++ CPP/7zip/Compress/Rar2Decoder.h
+@@ -139,6 +139,7 @@ class CDecoder :
+ 
+   UInt64 m_PackSize;
+   bool m_IsSolid;
++  bool m_TablesOK;
+ 
+   void InitStructures();
+   UInt32 ReadBits(unsigned numBits);
+--- CPP/7zip/Compress/Rar3Decoder.cpp
++++ CPP/7zip/Compress/Rar3Decoder.cpp
+@@ -92,7 +92,8 @@ CDecoder::CDecoder():
+   _writtenFileSize(0),
+   _vmData(0),
+   _vmCode(0),
+-  m_IsSolid(false)
++  m_IsSolid(false),
++  _errorMode(false)
+ {
+   Ppmd7_Construct(&_ppmd);
+ }
+@@ -545,6 +546,9 @@ HRESULT CDecoder::ReadTables(bool &keepDecompressing)
+     return InitPPM();
+   }
+ 
++  TablesRead = false;
++  TablesOK = false;
++
+   _lzMode = true;
+   PrevAlignBits = 0;
+   PrevAlignCount = 0;
+@@ -606,6 +610,9 @@ HRESULT CDecoder::ReadTables(bool &keepDecompressing)
+       }
+     }
+   }
++  if (InputEofError())
++    return S_FALSE;
++
+   TablesRead = true;
+ 
+   // original code has check here:
+@@ -623,6 +630,9 @@ HRESULT CDecoder::ReadTables(bool &keepDecompressing)
+   RIF(m_LenDecoder.Build(&newLevels[kMainTableSize + kDistTableSize + kAlignTableSize]));
+ 
+   memcpy(m_LastLevels, newLevels, kTablesSizesSum);
++
++  TablesOK = true;
++
+   return S_OK;
+ }
+ 
+@@ -824,7 +834,12 @@ HRESULT CDecoder::CodeReal(ICompressProgressInfo *progress)
+     PpmEscChar = 2;
+     PpmError = true;
+     InitFilters();
++    _errorMode = false;
+   }
++
++  if (_errorMode)
++    return S_FALSE;
++
+   if (!m_IsSolid || !TablesRead)
+   {
+     bool keepDecompressing;
+@@ -838,6 +853,8 @@ HRESULT CDecoder::CodeReal(ICompressProgressInfo *progress)
+     bool keepDecompressing;
+     if (_lzMode)
+     {
++      if (!TablesOK)
++        return S_FALSE;
+       RINOK(DecodeLZ(keepDecompressing))
+     }
+     else
+@@ -901,8 +918,8 @@ STDMETHODIMP CDecoder::Code(ISequentialInStream *inStream, ISequentialOutStream
+     _unpackSize = outSize ? *outSize : (UInt64)(Int64)-1;
+     return CodeReal(progress);
+   }
+-  catch(const CInBufferException &e)  { return e.ErrorCode; }
+-  catch(...) { return S_FALSE; }
++  catch(const CInBufferException &e)  { _errorMode = true; return e.ErrorCode; }
++  catch(...) { _errorMode = true; return S_FALSE; }
+   // CNewException is possible here. But probably CNewException is caused
+   // by error in data stream.
+ }
+--- CPP/7zip/Compress/Rar3Decoder.h
++++ CPP/7zip/Compress/Rar3Decoder.h
+@@ -192,6 +192,7 @@ class CDecoder:
+   UInt32 _lastFilter;
+ 
+   bool m_IsSolid;
++  bool _errorMode;
+ 
+   bool _lzMode;
+   bool _unsupportedFilter;
+@@ -200,6 +201,7 @@ class CDecoder:
+   UInt32 PrevAlignCount;
+ 
+   bool TablesRead;
++  bool TablesOK;
+ 
+   CPpmd7 _ppmd;
+   int PpmEscChar;