I was recently looking at this CVE and CVE 2018 10115.patch.
According to upstream 7-zip [1], this bug was fixed in version 18.05. In
the upstream release announcement, someone asked about variables like
_errorMode that were introduced earlier to deal with CVE-2018-5996 [2]
and how they had been removed from this release.
The 7-Zip maintainer replied it was intentional and both CVEs should be
fixed with that code. I've diff'ed 18.03 and 18.05, and _errorMode is
either commented out or removed in the code, while the existing
CVE_2018_10115.patch still has them in addition to the _solidAllowed
stuff. I just package p7zip so I don't know much about how its
implementation works, but I figured it'd be a better idea to make the
CVE-2018-10115 patch more similar to what upstream had.
This new version is attached and follows what 18.05 upstream does.
[1] https://www.7-zip.org/history.txt
[2]
https://sourceforge.net/p/sevenzip/discussion/45797/thread/adc65bfa/#8b13
--- CPP/7zip/Compress/Rar1Decoder.cpp.orig 2019-02-24 20:16:23.682521000 +0100
+++ CPP/7zip/Compress/Rar1Decoder.cpp 2019-02-24 22:02:59.461303000 +0100
@@ -29,7 +29,7 @@
};
*/
-CDecoder::CDecoder(): m_IsSolid(false), _errorMode(false) { }
+CDecoder::CDecoder(): _isSolid(false), _solidAllowed(false) { }
void CDecoder::InitStructures()
{
@@ -345,7 +345,7 @@
void CDecoder::InitData()
{
- if (!m_IsSolid)
+ if (!_isSolid)
{
AvrPlcB = AvrLn1 = AvrLn2 = AvrLn3 = NumHuf = Buf60 = 0;
AvrPlc = 0x3500;
@@ -391,6 +391,11 @@
if (inSize == NULL || outSize == NULL)
return E_INVALIDARG;
+ if (_isSolid && !_solidAllowed)
+return S_FALSE;
+
+ _solidAllowed = false;
+
if (!m_OutWindowStream.Create(kHistorySize))
return E_OUTOFMEMORY;
if (!m_InBitStream.Create(1 << 20))
@@ -398,22 +403,18 @@
m_UnpackSize = (Int64)*outSize;
m_OutWindowStream.SetStream(outStream);
- m_OutWindowStream.Init(m_IsSolid);
+ m_OutWindowStream.Init(_isSolid);
m_InBitStream.SetStream(inStream);
m_InBitStream.Init();
// CCoderReleaser coderReleaser(this);
InitData();
- if (!m_IsSolid)
+ if (!_isSolid)
{
-_errorMode = false;
InitStructures();
InitHuff();
}
- if (_errorMode)
-return S_FALSE;
-
if (m_UnpackSize > 0)
{
GetFlagsBuf();
@@ -475,6 +476,7 @@
}
if (m_UnpackSize < 0)
return S_FALSE;
+ _solidAllowed = true;
return m_OutWindowStream.Flush();
}
@@ -482,16 +484,16 @@
const UInt64 *inSize, const UInt64 *outSize, ICompressProgressInfo *progress)
{
try { return CodeReal(inStream, outStream, inSize, outSize, progress); }
- catch(const CInBufferException ) { _errorMode = true; return e.ErrorCode; }
- catch(const CLzOutWindowException ) { _errorMode = true; return e.ErrorCode; }
- catch(...) { _errorMode = true; return S_FALSE; }
+ catch(const CInBufferException ) { return e.ErrorCode; }
+ catch(const CLzOutWindowException ) { return e.ErrorCode; }
+ catch(...) { return S_FALSE; }
}
STDMETHODIMP CDecoder::SetDecoderProperties2(const Byte *data, UInt32 size)
{
if (size < 1)
return E_INVALIDARG;
- m_IsSolid = ((data[0] & 1) != 0);
+ _isSolid = ((data[0] & 1) != 0);
return S_OK;
}
--- CPP/7zip/Compress/Rar1Decoder.h.orig 2019-02-24 20:16:23.683118000 +0100
+++ CPP/7zip/Compress/Rar1Decoder.h 2019-02-24 22:01:21.915855000 +0100
@@ -38,8 +38,8 @@
UInt32 LastLength;
Int64 m_UnpackSize;
- bool m_IsSolid;
- bool _errorMode;
+ bool _isSolid;
+ bool _solidAllowed;
UInt32 ReadBits(int numBits);
HRESULT CopyBlock(UInt32 distance, UInt32 len);
--- CPP/7zip/Compress/Rar2Decoder.cpp.orig 2019-02-24 20:16:23.683974000 +0100
+++ CPP/7zip/Compress/Rar2Decoder.cpp 2019-02-24 20:16:23.691384000 +0100
@@ -80,7 +80,8 @@
static const UInt32 kWindowReservSize = (1 << 22) + 256;
CDecoder::CDecoder():
- m_IsSolid(false),
+ _isSolid(false),
+ _solidAllowed(false),
m_TablesOK(false)
{
}
@@ -320,6 +321,10 @@
if (inSize == NULL || outSize == NULL)
return E_INVALIDARG;
+ if (_isSolid && !_solidAllowed)
+return S_FALSE;
+ _solidAllowed = false;
+
if (!m_OutWindowStream.Create(kHistorySize))
return E_OUTOFMEMORY;
if (!m_InBitStream.Create(1 << 20))
@@ -330,12 +335,12 @@
UInt64 pos = 0, unPackSize = *outSize;
m_OutWindowStream.SetStream(outStream);
- m_OutWindowStream.Init(m_IsSolid);
+ m_OutWindowStream.Init(_isSolid);
m_InBitStream.SetStream(inStream);
m_InBitStream.Init();
// CCoderReleaser coderReleaser(this);
- if (!m_IsSolid)
+ if (!_isSolid)
{
InitStructures();
if (unPackSize == 0)
@@ -343,6 +348,7 @@
if (m_InBitStream.GetProcessedSize() + 2 <= m_PackSize) // test it: probably incorrect;
if (!ReadTables())
return S_FALSE;
+ _solidAllowed = true;
return S_OK;
}
if (!ReadTables())
@@ -386,6 +392,9 @@
if (!ReadLastTables())
return S_FALSE;
+
+ _solidAllowed = true;
+
return
