[reactos] 01/01: [RTL] Allow RtlGetNextRange to be called on a finished iterator. CORE-6372

[Thomas Faber]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=2fb2f1e4c57b453a8a67b…

commit 2fb2f1e4c57b453a8a67b4a54ad72533acf0a8b1
Author:     Thomas Faber <thomas.faber(a)reactos.org>
AuthorDate: Sun Aug 16 16:18:25 2020 +0200
Commit:     Thomas Faber <thomas.faber(a)reactos.org>
CommitDate: Sun Aug 16 16:18:29 2020 +0200

    [RTL] Allow RtlGetNextRange to be called on a finished iterator. CORE-6372
    
    Fixes crash in kmtest:RtlRangeList.
---
 sdk/lib/rtl/rangelist.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/sdk/lib/rtl/rangelist.c b/sdk/lib/rtl/rangelist.c
index ab2de3e0369..e589d43812a 100644
--- a/sdk/lib/rtl/rangelist.c
+++ b/sdk/lib/rtl/rangelist.c
@@ -499,6 +499,12 @@ RtlGetNextRange(IN OUT PRTL_RANGE_LIST_ITERATOR Iterator,
     if (Iterator->Stamp != RangeList->Stamp)
         return STATUS_INVALID_PARAMETER;
 
+    if (Iterator->Current == NULL)
+    {
+        *Range = NULL;
+        return STATUS_NO_MORE_ENTRIES;
+    }
+
     if (MoveForwards)
     {
         Next = ((PRTL_RANGE_ENTRY)Iterator->Current)->Entry.Flink;
@@ -509,7 +515,11 @@ RtlGetNextRange(IN OUT PRTL_RANGE_LIST_ITERATOR Iterator,
     }
 
     if (Next == Iterator->RangeListHead)
+    {
+        Iterator->Current = NULL;
+        *Range = NULL;
         return STATUS_NO_MORE_ENTRIES;
+    }
 
     Iterator->Current = Next;
     *Range = &((PRTL_RANGE_ENTRY)Next)->Range;