NetworkPkg TcpDxe: SECURITY PATCH CVE-2023-45236

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4541
REF: https://www.rfc-editor.org/rfc/rfc1948.txt
REF: https://www.rfc-editor.org/rfc/rfc6528.txt
REF: https://www.rfc-editor.org/rfc/rfc9293.txt

Bug Overview:
PixieFail Bug #8
CVE-2023-45236
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

Updates TCP ISN generation to use a cryptographic hash of the
connection's identifying parameters and a secret key.
This prevents an attacker from guessing the ISN used for some other
connection.

This is follows the guidance in RFC 1948, RFC 6528, and RFC 9293.

RFC: 9293 Section 3.4.1.  Initial Sequence Number Selection

   A TCP implementation MUST use the above type of "clock" for clock-
   driven selection of initial sequence numbers (MUST-8), and SHOULD
   generate its initial sequence numbers with the expression:

   ISN = M + F(localip, localport, remoteip, remoteport, secretkey)

   where M is the 4 microsecond timer, and F() is a pseudorandom
   function (PRF) of the connection's identifying parameters ("localip,
   localport, remoteip, remoteport") and a secret key ("secretkey")
   (SHLD-1).  F() MUST NOT be computable from the outside (MUST-9), or
   an attacker could still guess at sequence numbers from the ISN used
   for some other connection.  The PRF could be implemented as a
   cryptographic hash of the concatenation of the TCP connection
   parameters and some secret data.  For discussion of the selection of
   a specific hash algorithm and management of the secret key data,
   please see Section 3 of [42].

   For each connection there is a send sequence number and a receive
   sequence number.  The initial send sequence number (ISS) is chosen by
   the data sending TCP peer, and the initial receive sequence number
   (IRS) is learned during the connection-establishing procedure.

   For a connection to be established or initialized, the two TCP peers
   must synchronize on each other's initial sequence numbers.  This is
   done in an exchange of connection-establishing segments carrying a
   control bit called "SYN" (for synchronize) and the initial sequence
   numbers.  As a shorthand, segments carrying the SYN bit are also
   called "SYNs".  Hence, the solution requires a suitable mechanism for
   picking an initial sequence number and a slightly involved handshake
   to exchange the ISNs.

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>

8 files changed, 415 insertions, 49 deletions

diff --git a/NetworkPkg/SecurityFixes.yaml b/NetworkPkg/SecurityFixes.yaml
index 20a4555019..4305328425 100644
--- a/NetworkPkg/SecurityFixes.yaml
+++ b/NetworkPkg/SecurityFixes.yaml
@@ -122,6 +122,28 @@ CVE_2023_45235:
     - http://www.openwall.com/lists/oss-security/2024/01/16/2

     - http://packetstormsecurity.com/files/176574/PixieFail-Proof-Of-Concepts.html

     - https://blog.quarkslab.com/pixiefail-nine-vulnerabilities-in-tianocores-edk-ii-ipv6-network-stack.html

+CVE_2023_45236:

+  commit_titles:

+    - "NetworkPkg: TcpDxe: SECURITY PATCH CVE-2023-45236 Patch"

+  cve: CVE-2023-45236

+  date_reported: 2023-08-28 13:56 UTC

+  description: "Bug 08 - edk2/NetworkPkg: Predictable TCP Initial Sequence Numbers"

+  note:

+  files_impacted:

+    - NetworkPkg/Include/Library/NetLib.h

+    - NetworkPkg/TcpDxe/TcpDriver.c

+    - NetworkPkg/TcpDxe/TcpDxe.inf

+    - NetworkPkg/TcpDxe/TcpFunc.h

+    - NetworkPkg/TcpDxe/TcpInput.c

+    - NetworkPkg/TcpDxe/TcpMain.h

+    - NetworkPkg/TcpDxe/TcpMisc.c

+    - NetworkPkg/TcpDxe/TcpTimer.c

+  links:

+    - https://bugzilla.tianocore.org/show_bug.cgi?id=4541

+    - https://nvd.nist.gov/vuln/detail/CVE-2023-45236

+    - http://www.openwall.com/lists/oss-security/2024/01/16/2

+    - http://packetstormsecurity.com/files/176574/PixieFail-Proof-Of-Concepts.html

+    - https://blog.quarkslab.com/pixiefail-nine-vulnerabilities-in-tianocores-edk-ii-ipv6-network-stack.html

 CVE_2023_45237:

   commit_titles:

     - "NetworkPkg:: SECURITY PATCH CVE 2023-45237"

diff --git a/NetworkPkg/TcpDxe/TcpDriver.c b/NetworkPkg/TcpDxe/TcpDriver.c
index 8fe6badd68..40bba4080c 100644
--- a/NetworkPkg/TcpDxe/TcpDriver.c
+++ b/NetworkPkg/TcpDxe/TcpDriver.c
@@ -83,6 +83,12 @@ EFI_SERVICE_BINDING_PROTOCOL  gTcpServiceBinding = {
   TcpServiceBindingDestroyChild

 };

 

+//

+// This is the handle for the Hash2ServiceBinding Protocol instance this driver produces

+// if the platform does not provide one.

+//

+EFI_HANDLE  mHash2ServiceHandle = NULL;

+

 /**

   Create and start the heartbeat timer for the TCP driver.

 

@@ -165,6 +171,23 @@ TcpDriverEntryPoint (
   EFI_STATUS  Status;

   UINT32      Random;

 

+  //

+  // Initialize the Secret used for hashing TCP sequence numbers

+  //

+  // Normally this should be regenerated periodically, but since

+  // this is only used for UEFI networking and not a general purpose

+  // operating system, it is not necessary to regenerate it.

+  //

+  Status = PseudoRandomU32 (&mTcpGlobalSecret);

+  if (EFI_ERROR (Status)) {

+    DEBUG ((DEBUG_ERROR, "%a failed to generate random number: %r\n", __func__, Status));

+    return Status;

+  }

+

+  //

+  // Get a random number used to generate a random port number

+  // Intentionally not linking this to mTcpGlobalSecret to avoid leaking information about the secret

+  //

   Status = PseudoRandomU32 (&Random);

   if (EFI_ERROR (Status)) {

     DEBUG ((DEBUG_ERROR, "%a Failed to generate random number: %r\n", __func__, Status));

@@ -207,9 +230,8 @@ TcpDriverEntryPoint (
   }

 

   //

-  // Initialize ISS and random port.

+  // Initialize the random port.

   //

-  mTcpGlobalIss   = Random % mTcpGlobalIss;

   mTcp4RandomPort = (UINT16)(TCP_PORT_KNOWN + (Random % TCP_PORT_KNOWN));

   mTcp6RandomPort = mTcp4RandomPort;

 

@@ -224,6 +246,8 @@ TcpDriverEntryPoint (
   @param[in]  IpVersion          IP_VERSION_4 or IP_VERSION_6.

 

   @retval EFI_OUT_OF_RESOURCES   Failed to allocate some resources.

+  @retval EFI_UNSUPPORTED        Service Binding Protocols are unavailable.

+  @retval EFI_ALREADY_STARTED    The TCP driver is already started on the controller.

   @retval EFI_SUCCESS            A new IP6 service binding private was created.

 

 **/

@@ -234,11 +258,13 @@ TcpCreateService (
   IN UINT8       IpVersion

   )

 {

-  EFI_STATUS        Status;

-  EFI_GUID          *IpServiceBindingGuid;

-  EFI_GUID          *TcpServiceBindingGuid;

-  TCP_SERVICE_DATA  *TcpServiceData;

-  IP_IO_OPEN_DATA   OpenData;

+  EFI_STATUS                    Status;

+  EFI_GUID                      *IpServiceBindingGuid;

+  EFI_GUID                      *TcpServiceBindingGuid;

+  TCP_SERVICE_DATA              *TcpServiceData;

+  IP_IO_OPEN_DATA               OpenData;

+  EFI_SERVICE_BINDING_PROTOCOL  *Hash2ServiceBinding;

+  EFI_HASH2_PROTOCOL            *Hash2Protocol;

 

   if (IpVersion == IP_VERSION_4) {

     IpServiceBindingGuid  = &gEfiIp4ServiceBindingProtocolGuid;

@@ -272,6 +298,33 @@ TcpCreateService (
     return EFI_UNSUPPORTED;

   }

 

+  Status = gBS->LocateProtocol (&gEfiHash2ProtocolGuid, NULL, (VOID **)&Hash2Protocol);

+  if (EFI_ERROR (Status)) {

+    //

+    // If we can't find the Hashing protocol, then we need to create one.

+    //

+

+    //

+    // Platform is expected to publish the hash service binding protocol to support TCP.

+    //

+    Status = gBS->LocateProtocol (

+                    &gEfiHash2ServiceBindingProtocolGuid,

+                    NULL,

+                    (VOID **)&Hash2ServiceBinding

+                    );

+    if (EFI_ERROR (Status) || (Hash2ServiceBinding == NULL) || (Hash2ServiceBinding->CreateChild == NULL)) {

+      return EFI_UNSUPPORTED;

+    }

+

+    //

+    // Create an instance of the hash protocol for this controller.

+    //

+    Status = Hash2ServiceBinding->CreateChild (Hash2ServiceBinding, &mHash2ServiceHandle);

+    if (EFI_ERROR (Status)) {

+      return EFI_UNSUPPORTED;

+    }

+  }

+

   //

   // Create the TCP service data.

   //

@@ -423,6 +476,7 @@ TcpDestroyService (
   EFI_STATUS                               Status;

   LIST_ENTRY                               *List;

   TCP_DESTROY_CHILD_IN_HANDLE_BUF_CONTEXT  Context;

+  EFI_SERVICE_BINDING_PROTOCOL             *Hash2ServiceBinding;

 

   ASSERT ((IpVersion == IP_VERSION_4) || (IpVersion == IP_VERSION_6));

 

@@ -439,6 +493,30 @@ TcpDestroyService (
     return EFI_SUCCESS;

   }

 

+  //

+  // Destroy the Hash2ServiceBinding instance if it is created by Tcp driver.

+  //

+  if (mHash2ServiceHandle != NULL) {

+    Status = gBS->LocateProtocol (

+                    &gEfiHash2ServiceBindingProtocolGuid,

+                    NULL,

+                    (VOID **)&Hash2ServiceBinding

+                    );

+    if (EFI_ERROR (Status) || (Hash2ServiceBinding == NULL) || (Hash2ServiceBinding->DestroyChild == NULL)) {

+      return EFI_UNSUPPORTED;

+    }

+

+    //

+    // Destroy the instance of the hashing protocol for this controller.

+    //

+    Status = Hash2ServiceBinding->DestroyChild (Hash2ServiceBinding, &mHash2ServiceHandle);

+    if (EFI_ERROR (Status)) {

+      return EFI_UNSUPPORTED;

+    }

+

+    mHash2ServiceHandle = NULL;

+  }

+

   Status = gBS->OpenProtocol (

                   NicHandle,

                   ServiceBindingGuid,

diff --git a/NetworkPkg/TcpDxe/TcpDxe.inf b/NetworkPkg/TcpDxe/TcpDxe.inf
index cf5423f4c5..76de4cf9ec 100644
--- a/NetworkPkg/TcpDxe/TcpDxe.inf
+++ b/NetworkPkg/TcpDxe/TcpDxe.inf
@@ -6,6 +6,7 @@
 #  stack has been loaded in system. This driver supports both IPv4 and IPv6 network stack.

 #

 #  Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>

+#  Copyright (c) Microsoft Corporation

 #

 #  SPDX-License-Identifier: BSD-2-Clause-Patent

 #

@@ -68,7 +69,6 @@
   NetLib

   IpIoLib

 

-

 [Protocols]

   ## SOMETIMES_CONSUMES

   ## SOMETIMES_PRODUCES

@@ -81,6 +81,12 @@
   gEfiIp6ServiceBindingProtocolGuid             ## TO_START

   gEfiTcp6ProtocolGuid                          ## BY_START

   gEfiTcp6ServiceBindingProtocolGuid            ## BY_START

+  gEfiHash2ProtocolGuid                         ## BY_START

+  gEfiHash2ServiceBindingProtocolGuid           ## BY_START

+

+[Guids]

+  gEfiHashAlgorithmMD5Guid                      ## CONSUMES

+  gEfiHashAlgorithmSha256Guid                   ## CONSUMES

 

 [Depex]

   gEfiHash2ServiceBindingProtocolGuid

diff --git a/NetworkPkg/TcpDxe/TcpFunc.h b/NetworkPkg/TcpDxe/TcpFunc.h
index a7af01fff2..c707bee3e5 100644
--- a/NetworkPkg/TcpDxe/TcpFunc.h
+++ b/NetworkPkg/TcpDxe/TcpFunc.h
@@ -2,7 +2,7 @@
   Declaration of external functions shared in TCP driver.

 

   Copyright (c) 2009 - 2014, Intel Corporation. All rights reserved.<BR>

-

+  Copyright (c) Microsoft Corporation

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

 **/

@@ -36,8 +36,11 @@ VOID
 

   @param[in, out]  Tcb               Pointer to the TCP_CB of this TCP instance.

 

+  @retval EFI_SUCCESS             The operation completed successfully

+  @retval others                  The underlying functions failed and could not complete the operation

+

 **/

-VOID

+EFI_STATUS

 TcpInitTcbLocal (

   IN OUT TCP_CB  *Tcb

   );

@@ -129,17 +132,6 @@ TcpCloneTcb (
   );

 

 /**

-  Compute an ISS to be used by a new connection.

-

-  @return The result ISS.

-

-**/

-TCP_SEQNO

-TcpGetIss (

-  VOID

-  );

-

-/**

   Get the local mss.

 

   @param[in]  Sock        Pointer to the socket to get mss.

@@ -202,8 +194,11 @@ TcpFormatNetbuf (
   @param[in, out]  Tcb          Pointer to the TCP_CB that wants to initiate a

                                 connection.

 

+  @retval EFI_SUCCESS             The operation completed successfully

+  @retval others                  The underlying functions failed and could not complete the operation

+

 **/

-VOID

+EFI_STATUS

 TcpOnAppConnect (

   IN OUT TCP_CB  *Tcb

   );

diff --git a/NetworkPkg/TcpDxe/TcpInput.c b/NetworkPkg/TcpDxe/TcpInput.c
index 97633a3908..a5d575ccaf 100644
--- a/NetworkPkg/TcpDxe/TcpInput.c
+++ b/NetworkPkg/TcpDxe/TcpInput.c
@@ -724,6 +724,7 @@ TcpInput (
   TCP_SEQNO   Urg;

   UINT16      Checksum;

   INT32       Usable;

+  EFI_STATUS  Status;

 

   ASSERT ((Version == IP_VERSION_4) || (Version == IP_VERSION_6));

 

@@ -872,7 +873,17 @@ TcpInput (
       Tcb->LocalEnd.Port  = Head->DstPort;

       Tcb->RemoteEnd.Port = Head->SrcPort;

 

-      TcpInitTcbLocal (Tcb);

+      Status = TcpInitTcbLocal (Tcb);

+      if (EFI_ERROR (Status)) {

+        DEBUG (

+          (DEBUG_ERROR,

+           "TcpInput: discard a segment because failed to init local end for TCB %p\n",

+           Tcb)

+          );

+

+        goto DISCARD;

+      }

+

       TcpInitTcbPeer (Tcb, Seg, &Option);

 

       TcpSetState (Tcb, TCP_SYN_RCVD);

diff --git a/NetworkPkg/TcpDxe/TcpMain.h b/NetworkPkg/TcpDxe/TcpMain.h
index c0c9b7f46e..4d5566ab93 100644
--- a/NetworkPkg/TcpDxe/TcpMain.h
+++ b/NetworkPkg/TcpDxe/TcpMain.h
@@ -3,7 +3,7 @@
   It is the common head file for all Tcp*.c in TCP driver.

 

   Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.<BR>

-

+  Copyright (c) Microsoft Corporation

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

 **/

@@ -13,6 +13,7 @@
 

 #include <Protocol/ServiceBinding.h>

 #include <Protocol/DriverBinding.h>

+#include <Protocol/Hash2.h>

 #include <Library/IpIoLib.h>

 #include <Library/DevicePathLib.h>

 #include <Library/PrintLib.h>

@@ -31,7 +32,7 @@ extern EFI_UNICODE_STRING_TABLE      *gTcpControllerNameTable;
 

 extern LIST_ENTRY  mTcpRunQue;

 extern LIST_ENTRY  mTcpListenQue;

-extern TCP_SEQNO   mTcpGlobalIss;

+extern TCP_SEQNO   mTcpGlobalSecret;

 extern UINT32      mTcpTick;

 

 ///

@@ -45,14 +46,6 @@ extern UINT32      mTcpTick;
 

 #define TCP_EXPIRE_TIME  65535

 

-///

-/// The implementation selects the initial send sequence number and the unit to

-/// be added when it is increased.

-///

-#define TCP_BASE_ISS         0x4d7e980b

-#define TCP_ISS_INCREMENT_1  2048

-#define TCP_ISS_INCREMENT_2  100

-

 typedef union {

   EFI_TCP4_CONFIG_DATA    Tcp4CfgData;

   EFI_TCP6_CONFIG_DATA    Tcp6CfgData;

@@ -774,4 +767,50 @@ Tcp6Poll (
   IN EFI_TCP6_PROTOCOL  *This

   );

 

+/**

+  Retrieves the Initial Sequence Number (ISN) for a TCP connection identified by local

+  and remote IP addresses and ports.

+

+  This method is based on https://datatracker.ietf.org/doc/html/rfc9293#section-3.4.1

+  Where the ISN is computed as follows:

+    ISN = TimeStamp + MD5(LocalIP, LocalPort, RemoteIP, RemotePort, Secret)

+

+  Otherwise:

+    ISN = M + F(localip, localport, remoteip, remoteport, secretkey)

+

+    "Here M is the 4 microsecond timer, and F() is a pseudorandom function (PRF) of the

+    connection's identifying parameters ("localip, localport, remoteip, remoteport")

+    and a secret key ("secretkey") (SHLD-1). F() MUST NOT be computable from the

+    outside (MUST-9), or an attacker could still guess at sequence numbers from the

+    ISN used for some other connection. The PRF could be implemented as a

+    cryptographic hash of the concatenation of the TCP connection parameters and some

+    secret data. For discussion of the selection of a specific hash algorithm and

+    management of the secret key data."

+

+  @param[in]       LocalIp        A pointer to the local IP address of the TCP connection.

+  @param[in]       LocalIpSize    The size, in bytes, of the LocalIp buffer.

+  @param[in]       LocalPort      The local port number of the TCP connection.

+  @param[in]       RemoteIp       A pointer to the remote IP address of the TCP connection.

+  @param[in]       RemoteIpSize   The size, in bytes, of the RemoteIp buffer.

+  @param[in]       RemotePort     The remote port number of the TCP connection.

+  @param[out]      Isn            A pointer to the variable that will receive the Initial

+                                  Sequence Number (ISN).

+

+  @retval EFI_SUCCESS             The operation completed successfully, and the ISN was

+                                  retrieved.

+  @retval EFI_INVALID_PARAMETER   One or more of the input parameters are invalid.

+  @retval EFI_UNSUPPORTED         The operation is not supported.

+

+**/

+EFI_STATUS

+TcpGetIsn (

+  IN UINT8       *LocalIp,

+  IN UINTN       LocalIpSize,

+  IN UINT16      LocalPort,

+  IN UINT8       *RemoteIp,

+  IN UINTN       RemoteIpSize,

+  IN UINT16      RemotePort,

+  OUT TCP_SEQNO  *Isn

+  );

+

 #endif

diff --git a/NetworkPkg/TcpDxe/TcpMisc.c b/NetworkPkg/TcpDxe/TcpMisc.c
index c93212d47d..3310306f63 100644
--- a/NetworkPkg/TcpDxe/TcpMisc.c
+++ b/NetworkPkg/TcpDxe/TcpMisc.c
@@ -3,7 +3,7 @@
 

   (C) Copyright 2014 Hewlett-Packard Development Company, L.P.<BR>

   Copyright (c) 2009 - 2017, Intel Corporation. All rights reserved.<BR>

-

+  Copyright (c) Microsoft Corporation

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

 **/

@@ -20,7 +20,34 @@ LIST_ENTRY  mTcpListenQue = {
   &mTcpListenQue

 };

 

-TCP_SEQNO  mTcpGlobalIss = TCP_BASE_ISS;

+//

+// The Session secret

+// This must be initialized to a random value at boot time

+//

+TCP_SEQNO  mTcpGlobalSecret;

+

+//

+// Union to hold either an IPv4 or IPv6 address

+// This is used to simplify the ISN hash computation

+//

+typedef union {

+  UINT8    IPv4[4];

+  UINT8    IPv6[16];

+} NETWORK_ADDRESS;

+

+//

+// The ISN is computed by hashing this structure

+// It is initialized with the local and remote IP addresses and ports

+// and the secret

+//

+//

+typedef struct {

+  UINT16             LocalPort;

+  UINT16             RemotePort;

+  NETWORK_ADDRESS    LocalAddress;

+  NETWORK_ADDRESS    RemoteAddress;

+  TCP_SEQNO          Secret;

+} ISN_HASH_CTX;

 

 CHAR16  *mTcpStateName[] = {

   L"TCP_CLOSED",

@@ -41,12 +68,18 @@ CHAR16  *mTcpStateName[] = {
 

   @param[in, out]  Tcb               Pointer to the TCP_CB of this TCP instance.

 

+  @retval EFI_SUCCESS             The operation completed successfully

+  @retval others                  The underlying functions failed and could not complete the operation

+

 **/

-VOID

+EFI_STATUS

 TcpInitTcbLocal (

   IN OUT TCP_CB  *Tcb

   )

 {

+  TCP_SEQNO   Isn;

+  EFI_STATUS  Status;

+

   //

   // Compute the checksum of the fixed parts of pseudo header

   //

@@ -57,6 +90,16 @@ TcpInitTcbLocal (
                      0x06,

                      0

                      );

+

+    Status = TcpGetIsn (

+               Tcb->LocalEnd.Ip.v4.Addr,

+               sizeof (IPv4_ADDRESS),

+               Tcb->LocalEnd.Port,

+               Tcb->RemoteEnd.Ip.v4.Addr,

+               sizeof (IPv4_ADDRESS),

+               Tcb->RemoteEnd.Port,

+               &Isn

+               );

   } else {

     Tcb->HeadSum = NetIp6PseudoHeadChecksum (

                      &Tcb->LocalEnd.Ip.v6,

@@ -64,9 +107,25 @@ TcpInitTcbLocal (
                      0x06,

                      0

                      );

+

+    Status = TcpGetIsn (

+               Tcb->LocalEnd.Ip.v6.Addr,

+               sizeof (IPv6_ADDRESS),

+               Tcb->LocalEnd.Port,

+               Tcb->RemoteEnd.Ip.v6.Addr,

+               sizeof (IPv6_ADDRESS),

+               Tcb->RemoteEnd.Port,

+               &Isn

+               );

+  }

+

+  if (EFI_ERROR (Status)) {

+    DEBUG ((DEBUG_ERROR, "TcpInitTcbLocal: failed to get isn\n"));

+    ASSERT (FALSE);

+    return Status;

   }

 

-  Tcb->Iss    = TcpGetIss ();

+  Tcb->Iss    = Isn;

   Tcb->SndUna = Tcb->Iss;

   Tcb->SndNxt = Tcb->Iss;

 

@@ -82,6 +141,8 @@ TcpInitTcbLocal (
   Tcb->RetxmitSeqMax = 0;

 

   Tcb->ProbeTimerOn = FALSE;

+

+  return EFI_SUCCESS;

 }

 

 /**

@@ -506,18 +567,162 @@ TcpCloneTcb (
 }

 

 /**

-  Compute an ISS to be used by a new connection.

-

-  @return The resulting ISS.

+  Retrieves the Initial Sequence Number (ISN) for a TCP connection identified by local

+  and remote IP addresses and ports.

+

+  This method is based on https://datatracker.ietf.org/doc/html/rfc9293#section-3.4.1

+  Where the ISN is computed as follows:

+    ISN = TimeStamp + MD5(LocalIP, LocalPort, RemoteIP, RemotePort, Secret)

+

+  Otherwise:

+    ISN = M + F(localip, localport, remoteip, remoteport, secretkey)

+

+    "Here M is the 4 microsecond timer, and F() is a pseudorandom function (PRF) of the

+    connection's identifying parameters ("localip, localport, remoteip, remoteport")

+    and a secret key ("secretkey") (SHLD-1). F() MUST NOT be computable from the

+    outside (MUST-9), or an attacker could still guess at sequence numbers from the

+    ISN used for some other connection. The PRF could be implemented as a

+    cryptographic hash of the concatenation of the TCP connection parameters and some

+    secret data. For discussion of the selection of a specific hash algorithm and

+    management of the secret key data."

+

+  @param[in]       LocalIp        A pointer to the local IP address of the TCP connection.

+  @param[in]       LocalIpSize    The size, in bytes, of the LocalIp buffer.

+  @param[in]       LocalPort      The local port number of the TCP connection.

+  @param[in]       RemoteIp       A pointer to the remote IP address of the TCP connection.

+  @param[in]       RemoteIpSize   The size, in bytes, of the RemoteIp buffer.

+  @param[in]       RemotePort     The remote port number of the TCP connection.

+  @param[out]      Isn            A pointer to the variable that will receive the Initial

+                                  Sequence Number (ISN).

+

+  @retval EFI_SUCCESS             The operation completed successfully, and the ISN was

+                                  retrieved.

+  @retval EFI_INVALID_PARAMETER   One or more of the input parameters are invalid.

+  @retval EFI_UNSUPPORTED         The operation is not supported.

 

 **/

-TCP_SEQNO

-TcpGetIss (

-  VOID

+EFI_STATUS

+TcpGetIsn (

+  IN UINT8       *LocalIp,

+  IN UINTN       LocalIpSize,

+  IN UINT16      LocalPort,

+  IN UINT8       *RemoteIp,

+  IN UINTN       RemoteIpSize,

+  IN UINT16      RemotePort,

+  OUT TCP_SEQNO  *Isn

   )

 {

-  mTcpGlobalIss += TCP_ISS_INCREMENT_1;

-  return mTcpGlobalIss;

+  EFI_STATUS          Status;

+  EFI_HASH2_PROTOCOL  *Hash2Protocol;

+  EFI_HASH2_OUTPUT    HashResult;

+  ISN_HASH_CTX        IsnHashCtx;

+  EFI_TIME            TimeStamp;

+

+  //

+  // Check that the ISN pointer is valid

+  //

+  if (Isn == NULL) {

+    return EFI_INVALID_PARAMETER;

+  }

+

+  //

+  // The local ip may be a v4 or v6 address and may not be NULL

+  //

+  if ((LocalIp == NULL) || (LocalIpSize == 0) || (RemoteIp == NULL) || (RemoteIpSize == 0)) {

+    return EFI_INVALID_PARAMETER;

+  }

+

+  //

+  // the local ip may be a v4 or v6 address

+  //

+  if ((LocalIpSize != sizeof (EFI_IPv4_ADDRESS)) && (LocalIpSize != sizeof (EFI_IPv6_ADDRESS))) {

+    return EFI_INVALID_PARAMETER;

+  }

+

+  //

+  // Locate the Hash Protocol

+  //

+  Status = gBS->LocateProtocol (&gEfiHash2ProtocolGuid, NULL, (VOID **)&Hash2Protocol);

+  if (EFI_ERROR (Status)) {

+    DEBUG ((DEBUG_NET, "Failed to locate Hash Protocol: %r\n", Status));

+

+    //

+    // TcpCreateService(..) is expected to be called prior to this function

+    //

+    ASSERT_EFI_ERROR (Status);

+    return Status;

+  }

+

+  //

+  // Initialize the hash algorithm

+  //

+  Status = Hash2Protocol->HashInit (Hash2Protocol, &gEfiHashAlgorithmSha256Guid);

+  if (EFI_ERROR (Status)) {

+    DEBUG ((DEBUG_NET, "Failed to initialize sha256 hash algorithm: %r\n", Status));

+    return Status;

+  }

+

+  IsnHashCtx.LocalPort  = LocalPort;

+  IsnHashCtx.RemotePort = RemotePort;

+  IsnHashCtx.Secret     = mTcpGlobalSecret;

+

+  //

+  // Check the IP address family and copy accordingly

+  //

+  if (LocalIpSize == sizeof (EFI_IPv4_ADDRESS)) {

+    CopyMem (&IsnHashCtx.LocalAddress.IPv4, LocalIp, LocalIpSize);

+  } else if (LocalIpSize == sizeof (EFI_IPv6_ADDRESS)) {

+    CopyMem (&IsnHashCtx.LocalAddress.IPv6, LocalIp, LocalIpSize);

+  } else {

+    return EFI_INVALID_PARAMETER; // Unsupported address size

+  }

+

+  //

+  // Repeat the process for the remote IP address

+  //

+  if (RemoteIpSize == sizeof (EFI_IPv4_ADDRESS)) {

+    CopyMem (&IsnHashCtx.RemoteAddress.IPv4, RemoteIp, RemoteIpSize);

+  } else if (RemoteIpSize == sizeof (EFI_IPv6_ADDRESS)) {

+    CopyMem (&IsnHashCtx.RemoteAddress.IPv6, RemoteIp, RemoteIpSize);

+  } else {

+    return EFI_INVALID_PARAMETER; // Unsupported address size

+  }

+

+  //

+  // Compute the hash

+  // Update the hash with the data

+  //

+  Status = Hash2Protocol->HashUpdate (Hash2Protocol, (UINT8 *)&IsnHashCtx, sizeof (IsnHashCtx));

+  if (EFI_ERROR (Status)) {

+    DEBUG ((DEBUG_NET, "Failed to update hash: %r\n", Status));

+    return Status;

+  }

+

+  //

+  // Finalize the hash and retrieve the result

+  //

+  Status = Hash2Protocol->HashFinal (Hash2Protocol, &HashResult);

+  if (EFI_ERROR (Status)) {

+    DEBUG ((DEBUG_NET, "Failed to finalize hash: %r\n", Status));

+    return Status;

+  }

+

+  Status = gRT->GetTime (&TimeStamp, NULL);

+  if (EFI_ERROR (Status)) {

+    return Status;

+  }

+

+  //

+  // copy the first 4 bytes of the hash result into the ISN

+  //

+  CopyMem (Isn, HashResult.Md5Hash, sizeof (*Isn));

+

+  //

+  // now add the timestamp to the ISN as 4 microseconds units (1000 / 4 = 250)

+  //

+  *Isn += (TCP_SEQNO)TimeStamp.Nanosecond * 250;

+

+  return Status;

 }

 

 /**

@@ -721,17 +926,28 @@ TcpFormatNetbuf (
   @param[in, out]  Tcb          Pointer to the TCP_CB that wants to initiate a

                                 connection.

 

+  @retval EFI_SUCCESS             The operation completed successfully

+  @retval others                  The underlying functions failed and could not complete the operation

+

 **/

-VOID

+EFI_STATUS

 TcpOnAppConnect (

   IN OUT TCP_CB  *Tcb

   )

 {

-  TcpInitTcbLocal (Tcb);

+  EFI_STATUS  Status;

+

+  Status = TcpInitTcbLocal (Tcb);

+  if (EFI_ERROR (Status)) {

+    return Status;

+  }

+

   TcpSetState (Tcb, TCP_SYN_SENT);

 

   TcpSetTimer (Tcb, TCP_TIMER_CONNECT, Tcb->ConnectTimeout);

   TcpToSendData (Tcb, 1);

+

+  return EFI_SUCCESS;

 }

 

 /**

diff --git a/NetworkPkg/TcpDxe/TcpTimer.c b/NetworkPkg/TcpDxe/TcpTimer.c
index 5d2e124977..065b1bdf5f 100644
--- a/NetworkPkg/TcpDxe/TcpTimer.c
+++ b/NetworkPkg/TcpDxe/TcpTimer.c
@@ -2,7 +2,7 @@
   TCP timer related functions.

 

   Copyright (c) 2009 - 2010, Intel Corporation. All rights reserved.<BR>

-

+  Copyright (c) Microsoft Corporation

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

 **/

@@ -483,7 +483,6 @@ TcpTickingDpc (
   INT16       Index;

 

   mTcpTick++;

-  mTcpGlobalIss += TCP_ISS_INCREMENT_2;

 

   //

   // Don't use LIST_FOR_EACH, which isn't delete safe.