ovmf: Fix CVE-2023-45234

EDK2's Network Package is susceptible to a buffer overflow vulnerability
when processing DNS Servers option from a DHCPv6 Advertise message. This
vulnerability can be exploited by an attacker to gain unauthorized access
and potentially lead to a loss of Confidentiality, Integrity and/or
Availability.

References:
https://nvd.nist.gov/vuln/detail/CVE-2023-45234

Upstream-patches:
tianocore/edk2@1b53515
tianocore/edk2@458c582

Signed-off-by: Soumya Sambu <[email protected]>

meta/recipes-core/ovmf/ovmf/CVE-2023-45234-0001.patch

@@ -0,0 +1,154 @@
+From 1b53515d53d303166b2bbd31e2cc7f16fd0aecd7 Mon Sep 17 00:00:00 2001
+From: Doug Flick <[email protected]>
+Date: Fri, 26 Jan 2024 05:54:52 +0800
+Subject: [PATCH] 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 <[email protected]>
+Cc: Zachary Clark-williams <[email protected]>
+
+Signed-off-by: Doug Flick [MSFT] <[email protected]>
+Reviewed-by: Saloni Kasbekar <[email protected]>
+
+CVE: CVE-2023-45234
+
+Upstream-Status: Backport [https://github.com/tianocore/edk2/commit/1b53515d53d303166b2bbd31e2cc7f16fd0aecd7]
+
+Signed-off-by: Soumya Sambu <[email protected]>
+---
+ 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) {
+-- 
+2.40.0
+