https://git.reactos.org/?p=reactos.git;a=commitdiff;h=03294dd09763d8d2b4979a413c018ccd2a16fdde
commit 03294dd09763d8d2b4979a413c018ccd2a16fdde
Author: Pierre Schweitzer <pie...@reactos.org>
AuthorDate: Sat Oct 27 21:54:55 2018 +0200
Commit: Pierre Schweitzer <pie...@reactos.org>
CommitDate: Sat Oct 27 22:16:37 2018 +0200
[NTOSKRNL] Rewrite IoCheckEaBufferValidity() so that it's less magic
And make its coding style consistent with our rules
---
ntoskrnl/io/iomgr/util.c | 127 +++++++++++++++++++++++------------------------
1 file changed, 62 insertions(+), 65 deletions(-)
diff --git a/ntoskrnl/io/iomgr/util.c b/ntoskrnl/io/iomgr/util.c
index 7329dbf8f1..fb56f8d170 100644
--- a/ntoskrnl/io/iomgr/util.c
+++ b/ntoskrnl/io/iomgr/util.c
@@ -192,82 +192,79 @@ IoCheckEaBufferValidity(IN PFILE_FULL_EA_INFORMATION
EaBuffer,
IN ULONG EaLength,
OUT PULONG ErrorOffset)
{
- PFILE_FULL_EA_INFORMATION EaBufferEnd;
- ULONG NextEaBufferOffset;
- LONG IntEaLength;
+ ULONG NextEntryOffset;
+ UCHAR EaNameLength;
+ ULONG ComputedLength;
+ PFILE_FULL_EA_INFORMATION Current;
PAGED_CODE();
- /* Length of the rest */
- IntEaLength = EaLength;
- EaBufferEnd = EaBuffer;
-
- /* The rest length of the buffer */
- while (IntEaLength >= FIELD_OFFSET(FILE_FULL_EA_INFORMATION, EaName[0]))
+ /* We will browse all the entries */
+ for (Current = EaBuffer; ; Current =
(PFILE_FULL_EA_INFORMATION)((ULONG_PTR)Current + NextEntryOffset))
{
- /*
- * The rest of buffer must greater than
- * sizeof(FILE_FULL_EA_INFORMATION) + buffer
- */
- NextEaBufferOffset =
- EaBufferEnd->EaNameLength + EaBufferEnd->EaValueLength +
- FIELD_OFFSET(FILE_FULL_EA_INFORMATION, EaName[0]) + 1;
-
- if ((ULONG)IntEaLength >= NextEaBufferOffset)
+ /* Check that we have enough bits left for the current entry */
+ if (EaLength < FIELD_OFFSET(FILE_FULL_EA_INFORMATION, EaName))
+ {
+ goto FailPath;
+ }
+
+ EaNameLength = Current->EaNameLength;
+ ComputedLength = Current->EaValueLength + EaNameLength +
FIELD_OFFSET(FILE_FULL_EA_INFORMATION, EaName) + 1;
+ /* Check that we have enough bits left for storing the name and its
value */
+ if (EaLength < ComputedLength)
+ {
+ goto FailPath;
+ }
+
+ /* Make sure the name is null terminated */
+ if (Current->EaName[EaNameLength] != ANSI_NULL)
+ {
+ goto FailPath;
+ }
+
+ /* Get the next entry offset */
+ NextEntryOffset = Current->NextEntryOffset;
+ /* If it's 0, it's a termination case */
+ if (NextEntryOffset == 0)
{
- /* is the EaBufferName terminated with zero? */
- if (EaBufferEnd->EaName[EaBufferEnd->EaNameLength]==0)
+ /* If we don't overflow! */
+ if (EaLength - ComputedLength < 0)
{
- /* more EaBuffers ahead */
- if (EaBufferEnd->NextEntryOffset == 0)
- {
- /* test the rest buffersize */
- IntEaLength = IntEaLength - NextEaBufferOffset;
- if (IntEaLength >= 0)
- {
- return STATUS_SUCCESS;
- }
- }
- else
- {
- /*
- * From MSDN:
- * http://msdn2.microsoft.com/en-us/library/ms795740.aspx
- * For all entries except the last one, the value of
- * NextEntryOffset must be greater than zero and
- * must fall on a ULONG boundary.
- */
- NextEaBufferOffset = ((NextEaBufferOffset + 3) & ~3);
- if ((EaBufferEnd->NextEntryOffset == NextEaBufferOffset) &&
- ((LONG)EaBufferEnd->NextEntryOffset > 0))
- {
- /*
- * The rest of buffer must be greater
- * than the following offset.
- */
- IntEaLength =
- IntEaLength - EaBufferEnd->NextEntryOffset;
-
- if (IntEaLength >= 0)
- {
- EaBufferEnd = (PFILE_FULL_EA_INFORMATION)
- ((ULONG_PTR)EaBufferEnd +
- EaBufferEnd->NextEntryOffset);
- continue;
- }
- }
- }
+ goto FailPath;
}
+
+ break;
}
- break;
- }
- if (ErrorOffset != NULL)
- {
- /* Calculate the error offset */
- *ErrorOffset = (ULONG)((ULONG_PTR)EaBufferEnd - (ULONG_PTR)EaBuffer);
+ /* Compare the next offset we computed with the provided one, they
must match */
+ if (ALIGN_UP_BY(ComputedLength, sizeof(ULONG)) != NextEntryOffset)
+ {
+ goto FailPath;
+ }
+
+ /* Check next entry offset value is positive */
+ if (NextEntryOffset < 0)
+ {
+ goto FailPath;
+ }
+
+ /* Compute the remaining bits */
+ EaLength -= NextEntryOffset;
+ /* We must have bits left */
+ if (EaLength < 0)
+ {
+ goto FailPath;
+ }
+
+ /* Move to the next entry */
}
+ /* If we end here, everything went OK */
+ return STATUS_SUCCESS;
+
+FailPath:
+ /* If we end here, we failed, set failed offset */
+ *ErrorOffset = (ULONG_PTR)Current - (ULONG_PTR)EaBuffer;
return STATUS_EA_LIST_INCONSISTENT;
}
