reactos/sdk/lib/drivers/ntoskrnl_vista/fsrtl.c

   1 /*
   2  * PROJECT:         ReactOS Kernel - Vista+ APIs
   3  * LICENSE:         GPL v2 - See COPYING in the top level directory
   4  * FILE:            lib/drivers/ntoskrnl_vista/fsrtl.c
   5  * PURPOSE:         FsRtl functions of Vista+
   6  * PROGRAMMERS:     Pierre Schweitzer <pierre@reactos.org>
   7  */
   8
   9 #include <ntdef.h>
  10 #include <ntifs.h>
  11
  12 NTKERNELAPI
  13 NTSTATUS
  14 NTAPI
  15 FsRtlRemoveDotsFromPath(IN PWSTR OriginalString,
  16                         IN USHORT PathLength,
  17                         OUT USHORT *NewLength)
  18 {
  19     USHORT Length, ReadPos, WritePos;
  20
  21     Length = PathLength / sizeof(WCHAR);
  22
  23     if (Length == 3 && OriginalString[0] == '\\' && OriginalString[1] == '.' && OriginalString[2] == '.')
  24     {
  25         return STATUS_IO_REPARSE_DATA_INVALID;
  26     }
  27
  28     if (Length == 2 && OriginalString[0] == '.' && OriginalString[1] == '.')
  29     {
  30         return STATUS_IO_REPARSE_DATA_INVALID;
  31     }
  32
  33     if (Length > 2 && OriginalString[0] == '.' && OriginalString[1] == '.' && OriginalString[2] == '\\')
  34     {
  35         return STATUS_IO_REPARSE_DATA_INVALID;
  36     }
  37
  38     for (ReadPos = 0, WritePos = 0; ReadPos < Length; ++WritePos)
  39     {
  40         for (; ReadPos > 0 && ReadPos < Length; ++ReadPos)
  41         {
  42             if (ReadPos < Length - 1 && OriginalString[ReadPos] == '\\' && OriginalString[ReadPos + 1] == '\\')
  43             {
  44                 continue;
  45             }
  46
  47             if (OriginalString[ReadPos] != '.')
  48             {
  49                 break;
  50             }
  51
  52             if (ReadPos == Length - 1)
  53             {
  54                 if (OriginalString[ReadPos - 1] == '\\')
  55                 {
  56                     if (WritePos > 1)
  57                     {
  58                         --WritePos;
  59                     }
  60
  61                     continue;
  62                 }
  63
  64                 OriginalString[WritePos] = '.';
  65                 ++WritePos;
  66                 continue;
  67             }
  68
  69             if (OriginalString[ReadPos + 1] == '\\')
  70             {
  71                 if (OriginalString[ReadPos - 1] != '\\')
  72                 {
  73                     OriginalString[WritePos] = '.';
  74                     ++WritePos;
  75                     continue;
  76                 }
  77             }
  78             else
  79             {
  80                 if (OriginalString[ReadPos + 1] != '.' || OriginalString[ReadPos - 1] != '\\' ||
  81                     ((ReadPos != Length - 2) && OriginalString[ReadPos + 2] != '\\'))
  82                 {
  83                     OriginalString[WritePos] = '.';
  84                     ++WritePos;
  85                     continue;
  86                 }
  87
  88                 for (WritePos -= 2; (SHORT)WritePos > 0 && OriginalString[WritePos] != '\\'; --WritePos);
  89
  90                 if ((SHORT)WritePos < 0 || OriginalString[WritePos] != '\\')
  91                 {
  92                     return STATUS_IO_REPARSE_DATA_INVALID;
  93                 }
  94
  95                 if (WritePos == 0 && ReadPos == Length - 2)
  96                 {
  97                     WritePos = 1;
  98                 }
  99             }
 100
 101             ++ReadPos;
 102         }
 103
 104         if (ReadPos >= Length)
 105         {
 106             break;
 107         }
 108
 109         OriginalString[WritePos] = OriginalString[ReadPos];
 110         ++ReadPos;
 111     }
 112
 113     *NewLength = WritePos * sizeof(WCHAR);
 114
 115     while (WritePos < Length)
 116     {
 117         OriginalString[WritePos++] = UNICODE_NULL;
 118     }
 119
 120     return STATUS_SUCCESS;
 121 }
 122
 123 FORCEINLINE
 124 BOOLEAN
 125 IsNullGuid(IN PGUID Guid)
 126 {
 127     if (Guid->Data1 == 0 && Guid->Data2 == 0 && Guid->Data3 == 0 &&
 128         ((ULONG *)Guid->Data4)[0] == 0 && ((ULONG *)Guid->Data4)[1] == 0)
 129     {
 130         return TRUE;
 131     }
 132
 133     return FALSE;
 134 }
 135
 136 FORCEINLINE
 137 BOOLEAN
 138 IsEven(IN USHORT Digit)
 139 {
 140     return ((Digit & 1) != 1);
 141 }
 142
 143 NTKERNELAPI
 144 NTSTATUS
 145 NTAPI
 146 FsRtlValidateReparsePointBuffer(IN ULONG BufferLength,
 147                                 IN PREPARSE_DATA_BUFFER ReparseBuffer)
 148 {
 149     USHORT DataLength;
 150     ULONG ReparseTag;
 151     PREPARSE_GUID_DATA_BUFFER GuidBuffer;
 152
 153     /* Validate data size range */
 154     if (BufferLength < REPARSE_DATA_BUFFER_HEADER_SIZE || BufferLength > MAXIMUM_REPARSE_DATA_BUFFER_SIZE)
 155     {
 156         return STATUS_IO_REPARSE_DATA_INVALID;
 157     }
 158
 159     GuidBuffer = (PREPARSE_GUID_DATA_BUFFER)ReparseBuffer;
 160     DataLength = ReparseBuffer->ReparseDataLength;
 161     ReparseTag = ReparseBuffer->ReparseTag;
 162
 163     /* Validate size consistency */
 164     if (DataLength + REPARSE_DATA_BUFFER_HEADER_SIZE != BufferLength && DataLength + REPARSE_GUID_DATA_BUFFER_HEADER_SIZE != BufferLength)
 165     {
 166         return STATUS_IO_REPARSE_DATA_INVALID;
 167     }
 168
 169     /* REPARSE_DATA_BUFFER is reserved for MS tags */
 170     if (DataLength + REPARSE_DATA_BUFFER_HEADER_SIZE == BufferLength && !IsReparseTagMicrosoft(ReparseTag))
 171     {
 172         return STATUS_IO_REPARSE_DATA_INVALID;
 173     }
 174
 175     /* If that a GUID data buffer, its GUID cannot be null, and it cannot contain a MS tag */
 176     if (DataLength + REPARSE_GUID_DATA_BUFFER_HEADER_SIZE == BufferLength && ((!IsReparseTagMicrosoft(ReparseTag)
 177         && IsNullGuid(&GuidBuffer->ReparseGuid)) || (ReparseTag == IO_REPARSE_TAG_MOUNT_POINT || ReparseTag == IO_REPARSE_TAG_SYMLINK)))
 178     {
 179         return STATUS_IO_REPARSE_DATA_INVALID;
 180     }
 181
 182     /* Check the data for MS non reserved tags */
 183     if (!(ReparseTag & 0xFFF0000) && ReparseTag != IO_REPARSE_TAG_RESERVED_ZERO && ReparseTag != IO_REPARSE_TAG_RESERVED_ONE)
 184     {
 185         /* If that's a mount point, validate the MountPointReparseBuffer branch */
 186         if (ReparseTag == IO_REPARSE_TAG_MOUNT_POINT)
 187         {
 188             /* We need information */
 189             if (DataLength >= REPARSE_DATA_BUFFER_HEADER_SIZE)
 190             {
 191                 /* Substitue must be the first in row */
 192                 if (!ReparseBuffer->MountPointReparseBuffer.SubstituteNameOffset)
 193                 {
 194                     /* Substitude must be null-terminated */
 195                     if (ReparseBuffer->MountPointReparseBuffer.PrintNameOffset == ReparseBuffer->MountPointReparseBuffer.SubstituteNameLength + sizeof(UNICODE_NULL))
 196                     {
 197                         /* There must just be the Offset/Length fields + buffer + 2 null chars */
 198                         if (DataLength == ReparseBuffer->MountPointReparseBuffer.PrintNameLength + ReparseBuffer->MountPointReparseBuffer.SubstituteNameLength + (FIELD_OFFSET(REPARSE_DATA_BUFFER, MountPointReparseBuffer.PathBuffer) - FIELD_OFFSET(REPARSE_DATA_BUFFER, MountPointReparseBuffer.SubstituteNameOffset)) + 2 * sizeof(UNICODE_NULL))
 199                         {
 200                             return STATUS_SUCCESS;
 201                         }
 202                     }
 203                 }
 204             }
 205         }
 206         else
 207         {
 208 #define FIELDS_SIZE (FIELD_OFFSET(REPARSE_DATA_BUFFER, SymbolicLinkReparseBuffer.PathBuffer) - FIELD_OFFSET(REPARSE_DATA_BUFFER, SymbolicLinkReparseBuffer.SubstituteNameOffset))
 209
 210             /* If that's not a symlink, accept the MS tag as it */
 211             if (ReparseTag != IO_REPARSE_TAG_SYMLINK)
 212             {
 213                 return STATUS_SUCCESS;
 214             }
 215
 216             /* We need information */
 217             if (DataLength >= FIELDS_SIZE)
 218             {
 219                 /* Validate lengths */
 220                 if (ReparseBuffer->SymbolicLinkReparseBuffer.SubstituteNameLength && ReparseBuffer->SymbolicLinkReparseBuffer.PrintNameLength)
 221                 {
 222                     /* Validate unicode strings */
 223                     if (IsEven(ReparseBuffer->SymbolicLinkReparseBuffer.SubstituteNameLength) && IsEven(ReparseBuffer->SymbolicLinkReparseBuffer.PrintNameLength) &&
 224                         IsEven(ReparseBuffer->SymbolicLinkReparseBuffer.SubstituteNameOffset) && IsEven(ReparseBuffer->SymbolicLinkReparseBuffer.PrintNameOffset))
 225                     {
 226                         if ((DataLength + REPARSE_DATA_BUFFER_HEADER_SIZE >= ReparseBuffer->SymbolicLinkReparseBuffer.SubstituteNameOffset + ReparseBuffer->SymbolicLinkReparseBuffer.SubstituteNameLength + FIELDS_SIZE + REPARSE_DATA_BUFFER_HEADER_SIZE)
 227                             && (DataLength + REPARSE_DATA_BUFFER_HEADER_SIZE >= ReparseBuffer->SymbolicLinkReparseBuffer.PrintNameLength + ReparseBuffer->SymbolicLinkReparseBuffer.PrintNameOffset + FIELDS_SIZE + REPARSE_DATA_BUFFER_HEADER_SIZE))
 228                         {
 229                             return STATUS_SUCCESS;
 230                         }
 231                     }
 232                 }
 233             }
 234 #undef FIELDS_SIZE
 235         }
 236
 237         return STATUS_IO_REPARSE_DATA_INVALID;
 238     }
 239
 240     return STATUS_IO_REPARSE_TAG_INVALID;
 241 }
 242