[Bug] Hashmap functions ignore Index parameter - all operations use bucket 0

[OnePaper]

Bug Description

The Index parameter in hashmap functions RtlHashmapEntryInsert, RtlHashmapEntryLookup, and RtlHashmapEntryDelete is never used. Instead, a local variable UINT32 index = 0 shadows the parameter, causing all hashmap operations to always access bucket 0.

Affected Files

• driver/containers/map.c

Affected Functions

1. RtlHashmapEntryInsert (line 153)
2. RtlHashmapEntryLookup (line 186)
3. RtlHashmapEntryDelete (line 214)

Root Cause

Each function declares a local variable UINT32 index = 0; that shadows the Index parameter:

PVOID
RtlHashmapEntryInsert(In PRTL_HASHMAP Hashmap, In UINT32 Index)
{
UINT32 index = 0; // ← Shadows the Index parameter
// ...
list_head = &(&Hashmap->buckets[index])->entry; // ← Uses local variable (always 0)
}## Impact

• Functional: All hashmap entries are inserted into, looked up from, and deleted from bucket 0 only, regardless of the hash key.
• Performance: The hashmap degrades to a linked list with O(n) lookup time instead of expected O(1) average.
• Correctness: Hash distribution is completely broken.

Proposed Fix

Remove the local UINT32 index = 0; declaration in all three functions and use the Index parameter directly:

PVOID
RtlHashmapEntryInsert(In PRTL_HASHMAP Hashmap, In UINT32 Index)
{

• UINT32 index = 0;
  PLIST_ENTRY list_head = NULL;
  PRTL_HASHMAP_ENTRY entry = NULL;
  PRTL_HASHMAP_ENTRY new_entry = NULL;

  if (!Hashmap->active)
  return NULL;

• list_head = &(&Hashmap->buckets[index])->entry;

• list_head = &(&Hashmap->buckets[Index])->entry;
  // ...
  }Apply the same fix to RtlHashmapEntryLookup and RtlHashmapEntryDelete.