edk2/edk2-NetworkPkg-UefiPxeBcDxe-SECURITY-PATCH-CVE-2023-4523.patch

From 38baf93892ec464490b6fe611c23b014f574344b Mon Sep 17 00:00:00 2001
From: Jon Maloy <jmaloy@redhat.com>
Date: Fri, 16 Feb 2024 10:48:05 -0500
Subject: [PATCH 07/15] NetworkPkg: UefiPxeBcDxe: SECURITY PATCH CVE-2023-45234
 Patch

RH-Author: Jon Maloy <jmaloy@redhat.com>
RH-MergeRequest: 56: Pixiefail issues in NetworkPkg package
RH-Jira: RHEL-21840 RHEL-21844 RHEL-21846 RHEL-21848 RHEL-21850 RHEL-21852
RH-Acked-by: Gerd Hoffmann <None>
RH-Acked-by: Oliver Steffen <osteffen@redhat.com>
RH-Commit: [7/15] c1baa0b2facbf0b63a90a0bfd55264af9f893098

JIRA: https://issues.redhat.com/browse/RHEL-21850
CVE: CVE-2022-45234
Upstream: Merged

commit 1b53515d53d303166b2bbd31e2cc7f16fd0aecd7
Author: Doug Flick <dougflick@microsoft.com>
Date:   Fri Jan 26 05:54:52 2024 +0800

    NetworkPkg: UefiPxeBcDxe: SECURITY PATCH CVE-2023-45234 Patch

    REF:https://bugzilla.tianocore.org/show_bug.cgi?id=4539

    Bug Details:
    PixieFail Bug #6
    CVE-2023-45234
    CVSS 8.3 : CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H
    CWE-119 Improper Restriction of Operations within the Bounds of
     a Memory Buffer

    Buffer overflow when processing DNS Servers option in a DHCPv6
    Advertise message

    Change Overview:

    Introduces a function to cache the Dns Server and perform sanitizing
    on the incoming DnsServerLen to ensure that the length is valid

    > + EFI_STATUS
    > + PxeBcCacheDnsServerAddresses (
    > +  IN PXEBC_PRIVATE_DATA        *Private,
    > +  IN PXEBC_DHCP6_PACKET_CACHE  *Cache6
    > +  )

    Additional code cleanup

    Cc: Saloni Kasbekar <saloni.kasbekar@intel.com>
    Cc: Zachary Clark-williams <zachary.clark-williams@intel.com>

    Signed-off-by: Doug Flick [MSFT] <doug.edk2@gmail.com>
    Reviewed-by: Saloni Kasbekar <saloni.kasbekar@intel.com>

Signed-off-by: Jon Maloy <jmaloy@redhat.com>
---
 NetworkPkg/UefiPxeBcDxe/PxeBcDhcp6.c | 71 +++++++++++++++++++++++++---
 1 file changed, 65 insertions(+), 6 deletions(-)

diff --git a/NetworkPkg/UefiPxeBcDxe/PxeBcDhcp6.c b/NetworkPkg/UefiPxeBcDxe/PxeBcDhcp6.c
index 425e0cf806..2b2d372889 100644
--- a/NetworkPkg/UefiPxeBcDxe/PxeBcDhcp6.c
+++ b/NetworkPkg/UefiPxeBcDxe/PxeBcDhcp6.c
@@ -3,6 +3,7 @@
 
   (C) Copyright 2014 Hewlett-Packard Development Company, L.P.<BR>
   Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) Microsoft Corporation
 
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
@@ -1312,6 +1313,65 @@ PxeBcSelectDhcp6Offer (
   }
 }
 
+/**
+  Cache the DHCPv6 DNS Server addresses
+
+  @param[in] Private               The pointer to PXEBC_PRIVATE_DATA.
+  @param[in] Cache6                The pointer to PXEBC_DHCP6_PACKET_CACHE.
+
+  @retval    EFI_SUCCESS           Cache the DHCPv6 DNS Server address successfully.
+  @retval    EFI_OUT_OF_RESOURCES  Failed to allocate resources.
+  @retval    EFI_DEVICE_ERROR      The DNS Server Address Length provided by a untrusted
+                                   option is not a multiple of 16 bytes (sizeof (EFI_IPv6_ADDRESS)).
+**/
+EFI_STATUS
+PxeBcCacheDnsServerAddresses (
+  IN PXEBC_PRIVATE_DATA        *Private,
+  IN PXEBC_DHCP6_PACKET_CACHE  *Cache6
+  )
+{
+  UINT16  DnsServerLen;
+
+  DnsServerLen = NTOHS (Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->OpLen);
+  //
+  // Make sure that the number is nonzero
+  //
+  if (DnsServerLen == 0) {
+    return EFI_DEVICE_ERROR;
+  }
+
+  //
+  // Make sure the DnsServerlen is a multiple of EFI_IPv6_ADDRESS (16)
+  //
+  if (DnsServerLen % sizeof (EFI_IPv6_ADDRESS) != 0) {
+    return EFI_DEVICE_ERROR;
+  }
+
+  //
+  // This code is currently written to only support a single DNS Server instead
+  // of multiple such as is spec defined (RFC3646, Section 3). The proper behavior
+  // would be to allocate the full space requested, CopyMem all of the data,
+  // and then add a DnsServerCount field to Private and update additional code
+  // that depends on this.
+  //
+  // To support multiple DNS servers the `AllocationSize` would need to be changed to DnsServerLen
+  //
+  // This is tracked in https://bugzilla.tianocore.org/show_bug.cgi?id=1886
+  //
+  Private->DnsServer = AllocateZeroPool (sizeof (EFI_IPv6_ADDRESS));
+  if (Private->DnsServer == NULL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  //
+  // Intentionally only copy over the first server address.
+  // To support multiple DNS servers, the `Length` would need to be changed to DnsServerLen
+  //
+  CopyMem (Private->DnsServer, Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->Data, sizeof (EFI_IPv6_ADDRESS));
+
+  return EFI_SUCCESS;
+}
+
 /**
   Handle the DHCPv6 offer packet.
 
@@ -1335,6 +1395,7 @@ PxeBcHandleDhcp6Offer (
   UINT32                    SelectIndex;
   UINT32                    Index;
 
+  ASSERT (Private != NULL);
   ASSERT (Private->SelectIndex > 0);
   SelectIndex = (UINT32)(Private->SelectIndex - 1);
   ASSERT (SelectIndex < PXEBC_OFFER_MAX_NUM);
@@ -1342,15 +1403,13 @@ PxeBcHandleDhcp6Offer (
   Status = EFI_SUCCESS;
 
   //
-  // First try to cache DNS server address if DHCP6 offer provides.
+  // First try to cache DNS server addresses if DHCP6 offer provides.
   //
   if (Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER] != NULL) {
-    Private->DnsServer = AllocateZeroPool (NTOHS (Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->OpLen));
-    if (Private->DnsServer == NULL) {
-      return EFI_OUT_OF_RESOURCES;
+    Status = PxeBcCacheDnsServerAddresses (Private, Cache6);
+    if (EFI_ERROR (Status)) {
+      return Status;
     }
-
-    CopyMem (Private->DnsServer, Cache6->OptList[PXEBC_DHCP6_IDX_DNS_SERVER]->Data, sizeof (EFI_IPv6_ADDRESS));
   }
 
   if (Cache6->OfferType == PxeOfferTypeDhcpBinl) {
-- 
2.39.3