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Fix RAR5 NTFS alt-stream check bypassing Zone.Identifier / overwriting default stream #235

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Fix RAR5 NTFS alt-stream check bypassing Zone.Identifier / overwriting default stream #235

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41 changes: 34 additions & 7 deletions CPP/7zip/UI/Common/ArchiveExtractCallback.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -159,9 +159,32 @@ static bool FindExt2(const char *p, const UString &name)

static const char * const k_ZoneId_StreamName_With_Colon_Prefix = ":Zone.Identifier";

// matches NTFS's own canonicalization, so a ":$DATA" suffix or extra leading ':'
// can't be used to slip a stream name past the checks below.
static void Normalize_AltStreamName_For_Ntfs(UString &s)
{
const unsigned kPostfixSize = 6; // ":$DATA"
if (s.Len() >= kPostfixSize
&& StringsAreEqualNoCase_Ascii(s.RightPtr(kPostfixSize), ":$DATA"))
s.DeleteFrom(s.Len() - kPostfixSize);
while (!s.IsEmpty() && s[0] == ':')
s.DeleteFrontal(1);
Comment on lines +170 to +171
}

bool Is_ZoneId_StreamName(const wchar_t *s)
{
return StringsAreEqualNoCase_Ascii(s, k_ZoneId_StreamName_With_Colon_Prefix + 1);
UString name = s;
Normalize_AltStreamName_For_Ntfs(name);
return StringsAreEqualNoCase_Ascii(name, k_ZoneId_StreamName_With_Colon_Prefix + 1);
}

// an alt-stream name that normalizes to empty refers to the file's unnamed
// data stream (e.g. "::$DATA"), which would overwrite the main file content.
static bool Is_DefaultDataStream_Name(const wchar_t *s)
{
UString name = s;
Normalize_AltStreamName_For_Ntfs(name);
return name.IsEmpty();
}

void ReadZoneFile_Of_BaseFile(CFSTR fileName, CByteBuffer &buf)
Expand Down Expand Up @@ -1686,13 +1709,17 @@ Z7_COM7F_IMF(CArchiveExtractCallback::GetStream(UInt32 index, ISequentialOutStre
#if defined(_WIN32) && !defined(UNDER_CE) && !defined(Z7_SFX)
if (askExtractMode == NArchive::NExtract::NAskMode::kExtract
&& !_testMode
&& _item.IsAltStream
&& ZoneBuf.Size() != 0
&& Is_ZoneId_StreamName(_item.AltStreamName))
if (ZoneMode != NExtract::NZoneIdMode::kOffice
|| _item.PathParts.IsEmpty()
|| FindExt2(kOfficeExtensions, _item.PathParts.Back()))
&& _item.IsAltStream)
{
if (Is_DefaultDataStream_Name(_item.AltStreamName))
return S_OK;
if (ZoneBuf.Size() != 0
Comment on lines +1713 to +1716
&& Is_ZoneId_StreamName(_item.AltStreamName))
if (ZoneMode != NExtract::NZoneIdMode::kOffice
|| _item.PathParts.IsEmpty()
|| FindExt2(kOfficeExtensions, _item.PathParts.Back()))
return S_OK;
}
#endif


Expand Down