[reactos] 01/01: [NTOS:MM] Properly fail for invalid sizes of data section mappings

[Jérôme Gardou]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=998870c5ea85eabdd2b4d…
commit 998870c5ea85eabdd2b4df798f86e8de08d8a71b
Author:     Jérôme Gardou <jerome.gardou(a)reactos.org>
AuthorDate: Mon Feb 8 14:33:08 2021 +0100
Commit:     Jérôme Gardou <zefklop(a)users.noreply.github.com>
CommitDate: Tue Mar 30 22:20:15 2021 +0200
    [NTOS:MM] Properly fail for invalid sizes of data section mappings
---
 ntoskrnl/mm/ARM3/section.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/ntoskrnl/mm/ARM3/section.c b/ntoskrnl/mm/ARM3/section.c
index 3e6a25b44db..1301267e6b3 100644
--- a/ntoskrnl/mm/ARM3/section.c
+++ b/ntoskrnl/mm/ARM3/section.c
@@ -1326,25 +1326,26 @@ MiMapViewOfDataSection(IN PCONTROL_AREA ControlArea,
     /* Check if the caller specified the view size */
     if (!(*ViewSize))
     {
+        LONGLONG ViewSizeLL;
+
         /* The caller did not, so pick a 64K aligned view size based on the offset */
         SectionOffset->LowPart &= ~(_64K - 1);
-        /* Make sure that we will not overflow */
-        if ((Section->SizeOfSection.QuadPart - SectionOffset->QuadPart) >
MAXLONG_PTR)
+        /* Calculate size and make sure this fits */
+        if (!NT_SUCCESS(RtlLongLongSub(Section->SizeOfSection.QuadPart,
SectionOffset->QuadPart, &ViewSizeLL))
+            || !NT_SUCCESS(RtlLongLongToSIZET(ViewSizeLL, ViewSize))
+            || (*ViewSize > MAXLONG_PTR))
         {
             MiDereferenceControlArea(ControlArea);
             return STATUS_INVALID_VIEW_SIZE;
         }
-
-        *ViewSize = (SIZE_T)(Section->SizeOfSection.QuadPart -
SectionOffset->QuadPart);
     }
     else
     {
-        /* A size was specified, align it to a 64K boundary */
-        *ViewSize += SectionOffset->LowPart & (_64K - 1);
-
-        /* Check for overflow or huge value */
-        if ((*ViewSize < (SectionOffset->LowPart & (_64K - 1))) || ((*ViewSize)
> MAXLONG_PTR))
+        /* A size was specified, align it to a 64K boundary
+         * and check for overflow or huge value. */
+        if (!NT_SUCCESS(RtlSIZETAdd(*ViewSize, SectionOffset->LowPart & (_64K -
1), ViewSize))
+            || (*ViewSize > MAXLONG_PTR))
         {
             MiDereferenceControlArea(ControlArea);
             return STATUS_INVALID_VIEW_SIZE;