[PATCH v2 5/6] NetworkPkg/IScsiDxe: support SHA256 in CHAP

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

Insert a SHA256 CHAP_HASH structure at the start of "mChapHash".

Update ISCSI_CHAP_MAX_DIGEST_SIZE to SHA256_DIGEST_SIZE (32).

This enables the initiator and the target to negotiate SHA256 for CHAP, in
preference to MD5.

Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Maciej Rabeda <maciej.rabeda@linux.intel.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Cc: Siyuan Fu <siyuan.fu@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3355
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>
---

Notes:
    v2:
    - pick up R-b's [Phil, Maciej]

 NetworkPkg/IScsiDxe/IScsiCHAP.h |  3 ++-
 NetworkPkg/IScsiDxe/IScsiCHAP.c | 12 ++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/NetworkPkg/IScsiDxe/IScsiCHAP.h b/NetworkPkg/IScsiDxe/IScsiCHAP.h
index 1e5cc0b287ed..e2df634c4e67 100644
--- a/NetworkPkg/IScsiDxe/IScsiCHAP.h
+++ b/NetworkPkg/IScsiDxe/IScsiCHAP.h
@@ -6,44 +6,45 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
 
 #ifndef _ISCSI_CHAP_H_
 #define _ISCSI_CHAP_H_
 
 #define ISCSI_AUTH_METHOD_CHAP                    "CHAP"
 
 #define ISCSI_KEY_CHAP_ALGORITHM                  "CHAP_A"
 #define ISCSI_KEY_CHAP_IDENTIFIER                 "CHAP_I"
 #define ISCSI_KEY_CHAP_CHALLENGE                  "CHAP_C"
 #define ISCSI_KEY_CHAP_NAME                       "CHAP_N"
 #define ISCSI_KEY_CHAP_RESPONSE                   "CHAP_R"
 
 //
 // Identifiers of supported CHAP hash algorithms:
 // https://www.iana.org/assignments/ppp-numbers/ppp-numbers.xhtml#ppp-numbers-9
 //
 #define ISCSI_CHAP_ALGORITHM_MD5                  5
+#define ISCSI_CHAP_ALGORITHM_SHA256               7
 
 //
 // Byte count of the largest digest over the above-listed
 // ISCSI_CHAP_ALGORITHM_* hash algorithms.
 //
-#define ISCSI_CHAP_MAX_DIGEST_SIZE                MD5_DIGEST_SIZE
+#define ISCSI_CHAP_MAX_DIGEST_SIZE                SHA256_DIGEST_SIZE
 
 #define ISCSI_CHAP_STEP_ONE                       1
 #define ISCSI_CHAP_STEP_TWO                       2
 #define ISCSI_CHAP_STEP_THREE                     3
 #define ISCSI_CHAP_STEP_FOUR                      4
 
 
 #pragma pack(1)
 
 typedef struct _ISCSI_CHAP_AUTH_CONFIG_NVDATA {
   UINT8 CHAPType;
   CHAR8 CHAPName[ISCSI_CHAP_NAME_STORAGE];
   CHAR8 CHAPSecret[ISCSI_CHAP_SECRET_STORAGE];
   CHAR8 ReverseCHAPName[ISCSI_CHAP_NAME_STORAGE];
   CHAR8 ReverseCHAPSecret[ISCSI_CHAP_SECRET_STORAGE];
 } ISCSI_CHAP_AUTH_CONFIG_NVDATA;
 
 #pragma pack()
 
diff --git a/NetworkPkg/IScsiDxe/IScsiCHAP.c b/NetworkPkg/IScsiDxe/IScsiCHAP.c
index 351bf329b739..80035ece9887 100644
--- a/NetworkPkg/IScsiDxe/IScsiCHAP.c
+++ b/NetworkPkg/IScsiDxe/IScsiCHAP.c
@@ -1,36 +1,48 @@
 /** @file
   This file is for Challenge-Handshake Authentication Protocol (CHAP)
   Configuration.
 
 Copyright (c) 2004 - 2018, Intel Corporation. All rights reserved.<BR>
 SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
 
 #include "IScsiImpl.h"
 
 //
 // Supported CHAP hash algorithms, mapped to sets of BaseCryptLib APIs and
 // macros. CHAP_HASH structures at lower subscripts in the array are preferred
 // by the initiator.
 //
 STATIC CONST CHAP_HASH mChapHash[] = {
+  {
+    ISCSI_CHAP_ALGORITHM_SHA256,
+    SHA256_DIGEST_SIZE,
+    Sha256GetContextSize,
+    Sha256Init,
+    Sha256Update,
+    Sha256Final
+  },
+  //
+  // Keep the deprecated MD5 entry at the end of the array (making MD5 the
+  // least preferred choice of the initiator).
+  //
   {
     ISCSI_CHAP_ALGORITHM_MD5,
     MD5_DIGEST_SIZE,
     Md5GetContextSize,
     Md5Init,
     Md5Update,
     Md5Final
   },
 };
 
 //
 // Ordered list of mChapHash[*].Algorithm values. It is formatted for the
 // CHAP_A=<A1,A2...> value string, by the IScsiCHAPInitHashList() function. It
 // is sent by the initiator in ISCSI_CHAP_STEP_ONE.
 //
 STATIC CHAR8 mChapHashListString[
                3 +                                      // UINT8 identifier in
                                                         //   decimal
                (1 + 3) * (ARRAY_SIZE (mChapHash) - 1) + // comma prepended for
-- 
2.19.1.3.g30247aa5d201