/******************************************************************************
* Copyright (c) 2012 - 2022 Xilinx, Inc. All rights reserved.
* SPDX-License-Identifier: MIT
******************************************************************************/
/*****************************************************************************/
/**
*
* @file rsa.c
*
* Contains code for the RSA authentication
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver Who Date Changes
* ----- ---- -------- -------------------------------------------------------
* 4.00a sgd 02/28/13 Initial release
* 6.00a kc 07/30/13 Added FSBL_DEBUG_RSA to print more RSA buffers
* Fix for CR#724165 - Partition Header used by FSBL is
* not authenticated
* Fix for CR#724166 - FSBL doesn’t use PPK authenticated
* by Boot ROM for authenticating
* the Partition images
* Fix for CR#722979 - Provide customer-friendly
* changelogs in FSBL
* 9.00a kc 04/16/14 Fix for CR#724166 - SetPpk() will fail on secure
* fallback unless FSBL* and FSBL are
* identical in length
* Fix for CR#791245 - Use of xilrsa in FSBL
* 10.0 vns 03/18/22 Fixed CR#1125470 to authenticate the parition header buffer
* which is being used instead of one from DDR. Modified
* prototype of AuthenticatePartition() API
* </pre>
*
* @note
*
******************************************************************************/
/***************************** Include Files *********************************/
#ifdef RSA_SUPPORT
#include "fsbl.h"
#include "rsa.h"
#include "xilrsa.h"
#ifdef XPAR_XWDTPS_0_BASEADDR
#include "xwdtps.h"
#endif
/************************** Constant Definitions *****************************/
/**************************** Type Definitions *******************************/
/***************** Macros (Inline Functions) Definitions *********************/
/************************** Function Prototypes ******************************/
#ifdef XPAR_XWDTPS_0_BASEADDR
extern XWdtPs Watchdog; /* Instance of WatchDog Timer */
#endif
/************************** Variable Definitions *****************************/
static u8 *PpkModular;
static u8 *PpkModularEx;
static u32 PpkExp;
static u32 PpkAlreadySet=0;
extern u32 FsblLength;
void FsblPrintArray (u8 *Buf, u32 Len, char *Str)
{
#ifdef FSBL_DEBUG_RSA
int Index;
fsbl_printf(DEBUG_INFO, "%s START\r\n", Str);
for (Index=0;Index<Len;Index++)
{
fsbl_printf(DEBUG_INFO, "%02x",Buf[Index]);
if ((Index+1)%16 == 0){
fsbl_printf(DEBUG_INFO, "\r\n");
}
}
fsbl_printf(DEBUG_INFO, "\r\n %s END\r\n",Str);
#endif
return;
}
/*****************************************************************************/
/**
*
* This function is used to set ppk pointer to ppk in OCM
*
* @param None
*
* @return
*
* @note None
*
******************************************************************************/
void SetPpk(void )
{
u32 PadSize;
u8 *PpkPtr;
/*
* Set PPK only if is not already set
*/
if(PpkAlreadySet == 0)
{
/*
* Set PpkPtr to PPK in OCM
*/
/*
* Skip FSBL Length
*/
PpkPtr = (u8 *)(FsblLength);
/*
* Skip to 64 byte Boundary
*/
PadSize = ((u32)PpkPtr % 64);
if(PadSize != 0)
{
PpkPtr += (64 - PadSize);
}
/*
* Increment the pointer by authentication Header size
*/
PpkPtr += RSA_HEADER_SIZE;
/*
* Increment the pointer by Magic word size
*/
PpkPtr += RSA_MAGIC_WORD_SIZE;
/*
* Set pointer to PPK
*/
PpkModular = (u8 *)PpkPtr;
PpkPtr += RSA_PPK_MODULAR_SIZE;
PpkModularEx = (u8 *)PpkPtr;
PpkPtr += RSA_PPK_MODULAR_EXT_SIZE;
PpkExp = *((u32 *)PpkPtr);
/*
* Setting variable to avoid resetting PPK pointers
*/
PpkAlreadySet=1;
}
return;
}
/*****************************************************************************/
/**
*
* This function Authenticate Partition Signature
*
* @param AC is the pointer to authentication certificate
* @param Hash is the pointer which holds the SHA2 digest of data
* to be authenticated.
*
* @return
* - XST_SUCCESS if Authentication passed
* - XST_FAILURE if Authentication failed
*
* @note None
*
******************************************************************************/
u32 AuthenticatePartition(u8 *Ac, u8* Hash)
{
u8 DecryptSignature[256];
u8 HashSignature[32];
u8 *SpkModular;
u8 *SpkModularEx;
u32 SpkExp;
u8 *SignaturePtr;
u32 Status;
#ifdef XPAR_XWDTPS_0_BASEADDR
/*
* Prevent WDT reset
*/
XWdtPs_RestartWdt(&Watchdog);
#endif
/*
* Point to Authentication Certificate
*/
SignaturePtr = (u8 *)Ac;
/*
* Increment the pointer by authentication Header size
*/
SignaturePtr += RSA_HEADER_SIZE;
/*
* Increment the pointer by Magic word size
*/
SignaturePtr += RSA_MAGIC_WORD_SIZE;
/*
* Increment the pointer beyond the PPK
*/
SignaturePtr += RSA_PPK_MODULAR_SIZE;
SignaturePtr += RSA_PPK_MODULAR_EXT_SIZE;
SignaturePtr += RSA_PPK_EXPO_SIZE;
/*
* Calculate Hash Signature
*/
sha_256((u8 *)SignaturePtr, (RSA_SPK_MODULAR_EXT_SIZE +
RSA_SPK_EXPO_SIZE + RSA_SPK_MODULAR_SIZE),
HashSignature);
FsblPrintArray(HashSignature, 32, "SPK Hash Calculated");
/*
* Extract SPK signature
*/
SpkModular = (u8 *)SignaturePtr;
SignaturePtr += RSA_SPK_MODULAR_SIZE;
SpkModularEx = (u8 *)SignaturePtr;
SignaturePtr += RSA_SPK_MODULAR_EXT_SIZE;
SpkExp = *((u32 *)SignaturePtr);
SignaturePtr += RSA_SPK_EXPO_SIZE;
/*
* Decrypt SPK Signature
*/
rsa2048_pubexp((RSA_NUMBER)DecryptSignature,
(RSA_NUMBER)SignaturePtr,
(u32)PpkExp,
(RSA_NUMBER)PpkModular,
(RSA_NUMBER)PpkModularEx);
FsblPrintArray(DecryptSignature, RSA_SPK_SIGNATURE_SIZE,
"SPK Decrypted Hash");
Status = RecreatePaddingAndCheck(DecryptSignature, HashSignature);
if (Status != XST_SUCCESS) {
fsbl_printf(DEBUG_INFO, "Partition SPK Signature "
"Authentication failed\r\n");
return XST_FAILURE;
}
SignaturePtr += RSA_SPK_SIGNATURE_SIZE;
/*
* Decrypt Partition Signature
*/
rsa2048_pubexp((RSA_NUMBER)DecryptSignature,
(RSA_NUMBER)SignaturePtr,
(u32)SpkExp,
(RSA_NUMBER)SpkModular,
(RSA_NUMBER)SpkModularEx);
FsblPrintArray(DecryptSignature, RSA_PARTITION_SIGNATURE_SIZE,
"Partition Decrypted Hash");
Status = RecreatePaddingAndCheck(DecryptSignature, Hash);
if (Status != XST_SUCCESS) {
fsbl_printf(DEBUG_INFO, "Partition Signature "
"Authentication failed\r\n");
return XST_FAILURE;
}
return XST_SUCCESS;
}
/*****************************************************************************/
/**
*
* This function recreates the and check signature
*
* @param Partition signature
* @param Partition hash value which includes boot header, partition data
* @return
* - XST_SUCCESS if check passed
* - XST_FAILURE if check failed
*
* @note None
*
******************************************************************************/
u32 RecreatePaddingAndCheck(u8 *signature, u8 *hash)
{
u8 T_padding[] = {0x30, 0x31, 0x30, 0x0D, 0x06, 0x09, 0x60, 0x86, 0x48,
0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20 };
u8 * pad_ptr = signature + 256;
u32 pad = 256 - 3 - 19 - 32;
u32 ii;
/*
* Re-Create PKCS#1v1.5 Padding
* MSB ----------------------------------------------------LSB
* 0x0 || 0x1 || 0xFF(for 202 bytes) || 0x0 || T_padding || SHA256 Hash
*/
if (*--pad_ptr != 0x00 || *--pad_ptr != 0x01) {
return XST_FAILURE;
}
for (ii = 0; ii < pad; ii++) {
if (*--pad_ptr != 0xFF) {
return XST_FAILURE;
}
}
if (*--pad_ptr != 0x00) {
return XST_FAILURE;
}
for (ii = 0; ii < sizeof(T_padding); ii++) {
if (*--pad_ptr != T_padding[ii]) {
return XST_FAILURE;
}
}
for (ii = 0; ii < 32; ii++) {
if (*--pad_ptr != hash[ii])
return XST_FAILURE;
}
return XST_SUCCESS;
}
#endif