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Patch UnRAR: don't replace symlinks with directories
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UnRAR logic replaces directory symlinks found within archive file entry
file paths with actual directories by deleting them after they're
extracted.

Unfortunately, this logic extends to deleting existing directories if you
set the `DestName` instead of the `DestPath` in this API:

  rc = RARProcessFile(hArchive, RAR_EXTRACT, NULL, destFilePath);

In the future UnRAR may change to disable the `LinksToDirs()` feature
if using the `DestName` parameter. In the meantime, this commit
completely disables it for our use case.
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@micahsnyder
micahsnyder committed Oct 20, 2023
1 parent 685a31a commit 68944dd
Showing 1 changed file with 28 additions and 32 deletions.
60 changes: 28 additions & 32 deletions libclamunrar/extract.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -78,7 +78,7 @@ void CmdExtract::DoExtract()
{
if (Cmd->ManualPassword)
Cmd->Password.Clean(); // Clean user entered password before processing next archive.

ReconstructDone=false; // Must be reset here, not in ExtractArchiveInit().
UseExactVolName=false; // Must be reset here, not in ExtractArchiveInit().
while (true)
Expand All @@ -94,7 +94,7 @@ void CmdExtract::DoExtract()
if (Cmd->ManualPassword)
Cmd->Password.Clean();

if (TotalFileCount==0 && Cmd->Command[0]!='I' &&
if (TotalFileCount==0 && Cmd->Command[0]!='I' &&
ErrHandler.GetErrorCode()!=RARX_BADPWD) // Not in case of wrong archive password.
{
if (!PasswordCancelled)
Expand Down Expand Up @@ -236,7 +236,7 @@ EXTRACT_ARC_CODE CmdExtract::ExtractArchive()
return EXTRACT_ARC_REPEAT;
}
#endif

// Calculate the total size of all accessible volumes.
// This size is necessary to display the correct total progress indicator.

Expand All @@ -245,7 +245,7 @@ EXTRACT_ARC_CODE CmdExtract::ExtractArchive()

while (true)
{
// First volume is already added to DataIO.TotalArcSize
// First volume is already added to DataIO.TotalArcSize
// in initial TotalArcSize calculation in DoExtract.
// So we skip it and start from second volume.
NextVolumeName(NextName,ASIZE(NextName),!Arc.NewNumbering);
Expand Down Expand Up @@ -490,7 +490,7 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
if (wcscmp(ArcFileName,RefList[I].RefName)==0)
{
ExtractRef *MatchedRef=&RefList[I];

if (!Cmd->Test) // While harmless, it is useless for 't'.
{
// If reference source isn't selected, but target is selected,
Expand All @@ -509,13 +509,13 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
RefTarget=true; // Need it even for 't' to test the reference source.
break;
}

if (Arc.FileHead.Encrypted && Cmd->SkipEncrypted)
if (Arc.Solid)
return false; // Abort the entire extraction for solid archive.
else
MatchFound=false; // Skip only the current file for non-solid archive.

if (MatchFound || RefTarget || (SkipSolid=Arc.Solid)!=0)
{
// First common call of uiStartFileExtract. It is done before overwrite
Expand All @@ -537,10 +537,10 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
{
if (FD.mtime >= Arc.FileHead.mtime)
{
// If directory already exists and its modification time is newer
// than start of extraction, it is likely it was created
// when creating a path to one of already extracted items.
// In such case we'll better update its time even if archived
// If directory already exists and its modification time is newer
// than start of extraction, it is likely it was created
// when creating a path to one of already extracted items.
// In such case we'll better update its time even if archived
// directory is older.

if (!FD.IsDir || FD.mtime<StartTime)
Expand Down Expand Up @@ -642,10 +642,6 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
wcsncpyz(DestFileName,Cmd->DllDestName,ASIZE(DestFileName));
#endif

if (ExtrFile && Command!='P' && !Cmd->Test && !Cmd->AbsoluteLinks &&
ConvertSymlinkPaths)
ExtrFile=LinksToDirs(DestFileName,Cmd->ExtrPath,LastCheckedSymlink);

File CurFile;

bool LinkEntry=Arc.FileHead.RedirType!=FSREDIR_NONE;
Expand Down Expand Up @@ -684,7 +680,7 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
ExtrFile=true;

// We changed SkipSolid, so we need to call uiStartFileExtract
// with "Skip" parameter to change the operation status
// with "Skip" parameter to change the operation status
// from "extracting" to "skipping". For example, it can be necessary
// if user answered "No" to overwrite prompt when unpacking
// a solid archive.
Expand Down Expand Up @@ -775,7 +771,7 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
if (Type==FSREDIR_HARDLINK || Type==FSREDIR_FILECOPY)
{
wchar RedirName[NM];

// 2022.11.15: Might be needed when unpacking WinRAR 5.0 links with
// Unix RAR. WinRAR 5.0 used \ path separators here, when beginning
// from 5.10 even Windows version uses / internally and converts
Expand Down Expand Up @@ -806,7 +802,7 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
// Unix symlink can have its own owner data.
if (LinkSuccess)
SetFileHeaderExtra(Cmd,Arc,DestFileName);

ConvertSymlinkPaths|=LinkSuccess && UpLink;

// We do not actually need to reset the cache here if we cache
Expand All @@ -826,7 +822,7 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
uiMsg(UIERROR_UNKNOWNEXTRA,Arc.FileName,ArcFileName);
LinkSuccess=false;
}

if (!LinkSuccess || Arc.Format==RARFMT15 && !FileCreateMode)
{
// RAR 5.x links have a valid data checksum even in case of
Expand Down Expand Up @@ -874,9 +870,9 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
else
if (Arc.FileHead.Method!=0 && Arc.FileHead.UnpSize>0 && ValidCRC)
AnySolidDataUnpackedWell=true;

bool BrokenFile=false;

// Checksum is not calculated in skip solid mode for performance reason.
if (!SkipSolid && ShowChecksum)
{
Expand All @@ -888,7 +884,7 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
}
else
{
if (Arc.FileHead.Encrypted && (!Arc.FileHead.UsePswCheck ||
if (Arc.FileHead.Encrypted && (!Arc.FileHead.UsePswCheck ||
Arc.BrokenHeader) && !AnySolidDataUnpackedWell)
uiMsg(UIERROR_CHECKSUMENC,Arc.FileName,ArcFileName);
else
Expand All @@ -909,7 +905,7 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
// We check SkipSolid to remove percent for skipped solid files only.
// We must not apply these \b to links with ShowChecksum==false
// and their possible error messages.
if (SkipSolid)
if (SkipSolid)
mprintf(L"\b\b\b\b\b ");
}

Expand All @@ -922,7 +918,7 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
bool SetAttrOnly=LinkEntry && Arc.FileHead.RedirType==FSREDIR_HARDLINK && LinkSuccess;

if (!TestMode && (Command=='X' || Command=='E') &&
(!LinkEntry || SetAttrOnly || Arc.FileHead.RedirType==FSREDIR_FILECOPY && LinkSuccess) &&
(!LinkEntry || SetAttrOnly || Arc.FileHead.RedirType==FSREDIR_FILECOPY && LinkSuccess) &&
(!BrokenFile || Cmd->KeepBroken))
{
// Below we use DestFileName instead of CurFile.FileName,
Expand All @@ -949,7 +945,7 @@ bool CmdExtract::ExtractCurrentFile(Archive &Arc,size_t HeaderSize,bool &Repeat)
Cmd->xmtime==EXTTIME_NONE ? NULL:&Arc.FileHead.mtime,
Cmd->xatime==EXTTIME_NONE ? NULL:&Arc.FileHead.atime);
}

#if defined(_WIN_ALL) && !defined(SFX_MODULE)
if (Cmd->SetCompressedAttr &&
(Arc.FileHead.FileAttr & FILE_ATTRIBUTE_COMPRESSED)!=0)
Expand Down Expand Up @@ -1094,7 +1090,7 @@ void CmdExtract::ExtrPrepareName(Archive &Arc,const wchar *ArcFileName,wchar *De
wcsncpyz(DestName,ArcFileName,DestSize);
return;
}

wcsncpyz(DestName,Cmd->ExtrPath,DestSize);

if (*Cmd->ExtrPath!=0)
Expand Down Expand Up @@ -1141,7 +1137,7 @@ void CmdExtract::ExtrPrepareName(Archive &Arc,const wchar *ArcFileName,wchar *De
{
size_t NameLength=wcslen(ArcFileName);
if (NameLength>=ArcPathLength && wcsnicompc(ArcPath,ArcFileName,ArcPathLength)==0 &&
(IsPathDiv(ArcPath[ArcPathLength-1]) ||
(IsPathDiv(ArcPath[ArcPathLength-1]) ||
IsPathDiv(ArcFileName[ArcPathLength]) || ArcFileName[ArcPathLength]==0))
{
ArcFileName+=Min(ArcPathLength,NameLength);
Expand Down Expand Up @@ -1460,12 +1456,12 @@ bool CmdExtract::CheckUnpVer(Archive &Arc,const wchar *ArcFileName)
// Find non-matched reference sources in solid and non-solid archives.
// Detect the optimal start position for semi-solid archives
// and optimal start volume for independent solid volumes.
//
//
// Alternatively we could collect references while extracting an archive
// and perform the second extraction pass for references only.
// But it would be slower for solid archives than scaning headers
// in first pass and extracting everything in second, as implemented now.
//
//
void CmdExtract::AnalyzeArchive(const wchar *ArcName,bool Volume,bool NewNumbering)
{
FreeAnalyzeData(); // If processing non-first archive in multiple archives set.
Expand All @@ -1481,13 +1477,13 @@ void CmdExtract::AnalyzeArchive(const wchar *ArcName,bool Volume,bool NewNumberi
GetFirstVolIfFullSet(ArcName,NewNumbering,NextName,ASIZE(NextName));
else
wcsncpyz(NextName,ArcName,ASIZE(NextName));

bool MatchFound=false;
bool PrevMatched=false;
bool OpenNext=false;

bool FirstVolume=true;

// We shall set FirstFile once for all volumes and not for each volume.
// So we do not reuse the outdated Analyze->StartPos from previous volume
// if extracted file resides completely in the beginning of current one.
Expand Down Expand Up @@ -1542,7 +1538,7 @@ void CmdExtract::AnalyzeArchive(const wchar *ArcName,bool Volume,bool NewNumberi
wcsncpyz(Analyze->StartName,NextName,ASIZE(Analyze->StartName));

// We shall set FirstFile once for all volumes for this code
// to work properly. Alternatively we could append
// to work properly. Alternatively we could append
// "|| Analyze->StartPos!=0" to the condition, so we do not reuse
// the outdated Analyze->StartPos value from previous volume.
if (!FirstFile)
Expand Down

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