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dll: FspShareCheck

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This commit is contained in:
Bill Zissimopoulos
2016-01-03 16:27:59 -08:00
parent 6f5a290a81
commit f2f9e9f94b
1 changed files with 48 additions and 0 deletions
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48
src/dll/access.c
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@@ -121,5 +121,53 @@ exit:
FSP_API NTSTATUS FspShareCheck(FSP_FILE_SYSTEM *FileSystem,
FSP_FSCTL_TRANSACT_REQ *Request, FSP_FILE_NODE *FileNode)
{
DWORD DesiredAccess = Request->Req.Create.DesiredAccess;
DWORD ShareAccess = Request->Req.Create.ShareAccess;
BOOLEAN ReadAccess, WriteAccess, DeleteAccess;
BOOLEAN SharedRead, SharedWrite, SharedDelete;
ULONG OpenCount;
ReadAccess = 0 != (DesiredAccess & (FILE_READ_DATA | FILE_EXECUTE));
WriteAccess = 0 != (DesiredAccess & (FILE_WRITE_DATA | FILE_APPEND_DATA));
DeleteAccess = 0 != (DesiredAccess & DELETE);
if (ReadAccess || WriteAccess || DeleteAccess)
{
SharedRead = 0 != (ShareAccess & FILE_SHARE_READ);
SharedWrite = 0 != (ShareAccess & FILE_SHARE_WRITE);
SharedDelete = 0 != (ShareAccess & FILE_SHARE_DELETE);
OpenCount = FileNode->ShareAccess.OpenCount;
/*
* IF ReadAccess AND there are already some exclusive readers
* OR WriteAccess AND there are already some exclusive writers
* OR DeleteAccess AND there are already some exclusive deleters
* OR exclusive read requested AND there are already some readers
* OR exclusive write requested AND there are already some writers
* OR exclusive delete requested AND there are already some deleters
*/
if (ReadAccess && (FileNode->ShareAccess.SharedRead < OpenCount))
return STATUS_SHARING_VIOLATION;
if (WriteAccess && (FileNode->ShareAccess.SharedWrite < OpenCount))
return STATUS_SHARING_VIOLATION;
if (DeleteAccess && (FileNode->ShareAccess.SharedDelete < OpenCount))
return STATUS_SHARING_VIOLATION;
if (!SharedRead && 0 != FileNode->ShareAccess.Readers)
return STATUS_SHARING_VIOLATION;
if (!SharedWrite && 0 != FileNode->ShareAccess.Writers)
return STATUS_SHARING_VIOLATION;
if (!SharedDelete && 0 != FileNode->ShareAccess.Deleters)
return STATUS_SHARING_VIOLATION;
FileNode->ShareAccess.OpenCount++;
FileNode->ShareAccess.Readers += ReadAccess;
FileNode->ShareAccess.Writers += WriteAccess;
FileNode->ShareAccess.Deleters += DeleteAccess;
FileNode->ShareAccess.SharedRead += SharedRead;
FileNode->ShareAccess.SharedWrite += SharedWrite;
FileNode->ShareAccess.SharedDelete += SharedDelete;
}
return STATUS_SUCCESS;
}