bool IsRelativeSymlinkSafe(const wchar *SrcName,const wchar *TargetName)
{
if (IsFullRootPath(SrcName))
return false;
int AllowedDepth=0;
while (*SrcName!=0)
{
if (IsPathDiv(SrcName[0]) && SrcName[1]!=0 && !IsPathDiv(SrcName[1]))
{
bool Dot=SrcName[1]=='.' && (IsPathDiv(SrcName[2]) || SrcName[2]==0);
bool Dot2=SrcName[1]=='.' && SrcName[2]=='.' && (IsPathDiv(SrcName[3]) || SrcName[3]==0);
if (!Dot && !Dot2)
AllowedDepth++;
}
SrcName++;
}
if (IsFullRootPath(TargetName)) // Catch root dir based /path/file paths.
return false;
for (int Pos=0;*TargetName!=0;Pos++)
{
bool Dot2=TargetName[0]=='.' && TargetName[1]=='.' &&
(IsPathDiv(TargetName[2]) || TargetName[2]==0) &&
(Pos==0 || IsPathDiv(*(TargetName-1)));
if (Dot2)
AllowedDepth--;
TargetName++;
}
return AllowedDepth>=0;
}
bool IsRelativeSymlinkSafe(CommandData *Cmd,const wchar *SrcName,const wchar *PrepSrcName,const wchar *TargetName)
{
// Catch root dir based /path/file paths also as stuff like \\?\.
// Do not check PrepSrcName here, it can be root based if destination path
// is a root based.
if (IsFullRootPath(SrcName) || IsFullRootPath(TargetName))
return false;
// We could check just prepared src name, but for extra safety
// we check both original (as from archive header) and prepared
// (after applying the destination path and -ep switches) names.
int AllowedDepth=CalcAllowedDepth(SrcName); // Original name depth.
// Remove the destination path from prepared name if any. We should not
// count the destination path depth, because the link target must point
// inside of this path, not outside of it.
size_t ExtrPathLength=wcslen(Cmd->ExtrPath);
if (ExtrPathLength>0 && wcsncmp(PrepSrcName,Cmd->ExtrPath,ExtrPathLength)==0)
{
PrepSrcName+=ExtrPathLength;
while (IsPathDiv(*PrepSrcName))
PrepSrcName++;
}
int PrepAllowedDepth=CalcAllowedDepth(PrepSrcName);
// Number of ".." in link target.
int UpLevels=0;
for (int Pos=0;*TargetName!=0;Pos++)
{
bool Dot2=TargetName[0]=='.' && TargetName[1]=='.' &&
(IsPathDiv(TargetName[2]) || TargetName[2]==0) &&
(Pos==0 || IsPathDiv(*(TargetName-1)));
if (Dot2)
UpLevels++;
TargetName++;
}
return AllowedDepth>=UpLevels && PrepAllowedDepth>=UpLevels;
}
