Re: [edk2-devel] [PATCH v1] MdeModulePkg/Ip4Dxe: Check the received package length (CVE-2019-14559).

["Laszlo Ersek" <lersek@redhat.com>]

On 02/17/20 08:43, Wu, Jiaxin wrote:
> This patch is to check the received package length to make sure the package
> has a valid length field.
> 
> Cc: Fu Siyuan <siyuan.fu@intel.com>
> Cc: Maciej Rabeda <maciej.rabeda@linux.intel.com>
> Signed-off-by: Wu Jiaxin <jiaxin.wu@intel.com>
> Reviewed-by: Siyuan Fu <siyuan.fu@intel.com>
> ---
>  NetworkPkg/Ip4Dxe/Ip4Input.c | 46 +++++++++++++++++++++++++++++++++++---------
>  1 file changed, 37 insertions(+), 9 deletions(-)

There are two patches on the list for CVE-2019-14559:

- [edk2-devel] [PATCH v1] MdeModulePkg/Ip4Dxe: Check the received package length (CVE-2019-14559).
- [edk2-devel] [PATCH 1/1] NetworkPkg/ArpDxe: Recycle invalid ARP packets(CVE-2019-14559).

sent by different submitters.

How do they relate to each other?

Also, while Nick's patch mentions TianoCore#2031, the current patch doesn't include a BZ link. Is the current patch for TianoCore#2032? (Per <https://bugzilla.tianocore.org/show_bug.cgi?id=2032#c8>, both BZs share the same CVE ID.)

Also, I remain confused (with comment 11 being the latest one, as of this time, in TianoCore#2032), whether the issue affects IPv4 only, IPv6 only, or both. This patch is only for IPv4, apparently.

If the present patch is related to TianoCore#2032, then please add a mailing list archive link to the BZ, and move the BZ to IN_PROGRESS status.

Laszlo

> 
> diff --git a/NetworkPkg/Ip4Dxe/Ip4Input.c b/NetworkPkg/Ip4Dxe/Ip4Input.c
> index fec242c71f..95fbd01d05 100644
> --- a/NetworkPkg/Ip4Dxe/Ip4Input.c
> +++ b/NetworkPkg/Ip4Dxe/Ip4Input.c
> @@ -1,9 +1,9 @@
>  /** @file
>    IP4 input process.
>  
> -Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) 2005 - 2020, Intel Corporation. All rights reserved.<BR>
>  (C) Copyright 2015 Hewlett-Packard Development Company, L.P.<BR>
>  
>  SPDX-License-Identifier: BSD-2-Clause-Patent
>  
>  **/
> @@ -709,14 +709,10 @@ Ip4PreProcessPacket (
>    UINT16                    Checksum;
>  
>    //
>    // Check if the IP4 header is correctly formatted.
>    //
> -  if ((*Packet)->TotalSize < IP4_MIN_HEADLEN) {
> -    return EFI_INVALID_PARAMETER;
> -  }
> -
>    HeadLen  = (Head->HeadLen << 2);
>    TotalLen = NTOHS (Head->TotalLen);
>  
>    //
>    // Mnp may deliver frame trailer sequence up, trim it off.
> @@ -806,10 +802,34 @@ Ip4PreProcessPacket (
>    }
>  
>    return EFI_SUCCESS;
>  }
>  
> +/**
> +  This function checks the IPv4 packet length.
> +
> +  @param[in]       Packet          Pointer to the IPv4 Packet to be checked.
> +
> +  @retval TRUE                   The input IPv4 packet length is valid.
> +  @retval FALSE                  The input IPv4 packet length is invalid.
> +
> +**/
> +BOOLEAN
> +Ip4IsValidPacketLength (
> +  IN NET_BUF        *Packet
> +  )
> +{
> +  //
> +  // Check the IP4 packet length.
> +  //
> +  if (Packet->TotalSize < IP4_MIN_HEADLEN) {
> +    return FALSE;
> +  }
> +
> +  return TRUE;
> +}
> +
>  /**
>    The IP4 input routine. It is called by the IP4_INTERFACE when a
>    IP4 fragment is received from MNP.
>  
>    @param[in]  Ip4Instance        The IP4 child that request the receive, most like
> @@ -842,10 +862,14 @@ Ip4AccpetFrame (
>  
>    if (EFI_ERROR (IoStatus) || (IpSb->State == IP4_SERVICE_DESTROY)) {
>      goto DROP;
>    }
>  
> +  if (!Ip4IsValidPacketLength (Packet)) {
> +    goto RESTART;
> +  }
> +
>    Head      = (IP4_HEAD *) NetbufGetByte (Packet, 0, NULL);
>    ASSERT (Head != NULL);
>    OptionLen = (Head->HeadLen << 2) - IP4_MIN_HEADLEN;
>    if (OptionLen > 0) {
>      Option = (UINT8 *) (Head + 1);
> @@ -888,14 +912,18 @@ Ip4AccpetFrame (
>    //
>    // If the packet is protected by tunnel mode, parse the inner Ip Packet.
>    //
>    ZeroMem (&ZeroHead, sizeof (IP4_HEAD));
>    if (0 == CompareMem (Head, &ZeroHead, sizeof (IP4_HEAD))) {
> -  // Packet may have been changed. Head, HeadLen, TotalLen, and
> -  // info must be reloaded before use. The ownership of the packet
> -  // is transferred to the packet process logic.
> -  //
> +    // Packet may have been changed. Head, HeadLen, TotalLen, and
> +    // info must be reloaded before use. The ownership of the packet
> +    // is transferred to the packet process logic.
> +    //
> +    if (!Ip4IsValidPacketLength (Packet)) {
> +      goto RESTART;
> +    }
> +    
>      Head = (IP4_HEAD *) NetbufGetByte (Packet, 0, NULL);
>      ASSERT (Head != NULL);
>      Status = Ip4PreProcessPacket (
>                 IpSb,
>                 &Packet,
>