SECURE BOOT: Add command for validation of images

1. esbc_validate command is meant for validating header and
   signature of images (Boot Script and ESBC uboot client).
   SHA-256 and RSA operations are performed using SEC block in HW.
   This command works on both PBL based and Non PBL based Freescale
   platforms.
   Command usage:
   esbc_validate img_hdr_addr [pub_key_hash]
2. ESBC uboot client can be linux. Additionally, rootfs and device
   tree blob can also be signed.
3. In the event of header or signature failure in validation,
   ITS and ITF bits determine further course of action.
4. In case of soft failure, appropriate error is dumped on console.
5. In case of hard failure, SoC is issued RESET REQUEST after
   dumping error on the console.
6. KEY REVOCATION Feature:
   QorIQ platforms like B4/T4 have support of srk key table and key
   revocation in ISBC code in Silicon.
   The srk key table allows the user to have a key table with multiple
   keys and revoke any key in case of particular key gets compromised.
   In case the ISBC code uses the key revocation and srk key table to
   verify the u-boot code, the subsequent chain of trust should also
   use the same.
6. ISBC KEY EXTENSION Feature:
   This feature allows large number of keys to be used for esbc validation
   of images. A set of public keys is being signed and validated by ISBC
   which can be further used for esbc validation of images.

Signed-off-by: Ruchika Gupta <ruchika.gupta@freescale.com>
Signed-off-by: Gaurav Rana <gaurav.rana@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>

2 files changed, 874 insertions, 0 deletions

diff --git a/board/freescale/common/cmd_esbc_validate.c b/board/freescale/common/cmd_esbc_validate.c
new file mode 100644
index 0000000..8500ba5
--- /dev/null
+++ b/board/freescale/common/cmd_esbc_validate.c
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2015 Freescale Semiconductor, Inc.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <command.h>
+#include <fsl_validate.h>
+
+static int do_esbc_validate(cmd_tbl_t *cmdtp, int flag, int argc,
+				char * const argv[])
+{
+	if (argc < 2)
+		return cmd_usage(cmdtp);
+
+	return fsl_secboot_validate(cmdtp, flag, argc, argv);
+}
+
+/***************************************************/
+static char esbc_validate_help_text[] =
+	"esbc_validate hdr_addr <hash_val> - Validates signature using\n"
+	"                          RSA verification\n"
+	"                          $hdr_addr Address of header of the image\n"
+	"                          to be validated.\n"
+	"                          $hash_val -Optional\n"
+	"                          It provides Hash of public/srk key to be\n"
+	"                          used to verify signature.\n";
+
+U_BOOT_CMD(
+	esbc_validate,	3,	0,	do_esbc_validate,
+	"Validates signature on a given image using RSA verification",
+	esbc_validate_help_text
+);
diff --git a/board/freescale/common/fsl_validate.c b/board/freescale/common/fsl_validate.c
new file mode 100644
index 0000000..5283648
--- /dev/null
+++ b/board/freescale/common/fsl_validate.c
@@ -0,0 +1,840 @@
+/*
+ * Copyright 2015 Freescale Semiconductor, Inc.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <fsl_validate.h>
+#include <fsl_secboot_err.h>
+#include <fsl_sfp.h>
+#include <fsl_sec.h>
+#include <command.h>
+#include <malloc.h>
+#include <dm/uclass.h>
+#include <u-boot/rsa-mod-exp.h>
+#include <hash.h>
+#include <fsl_secboot_err.h>
+#ifndef CONFIG_MPC85xx
+#include <asm/arch/immap_ls102xa.h>
+#endif
+
+#define SHA256_BITS	256
+#define SHA256_BYTES	(256/8)
+#define SHA256_NIBBLES	(256/4)
+#define NUM_HEX_CHARS	(sizeof(ulong) * 2)
+
+/* This array contains DER value for SHA-256 */
+static const u8 hash_identifier[] = { 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60,
+		0x86, 0x48, 0x01, 0x65,	0x03, 0x04, 0x02, 0x01, 0x05, 0x00,
+		0x04, 0x20
+		};
+
+static u8 hash_val[SHA256_BYTES];
+static const u8 barker_code[ESBC_BARKER_LEN] = { 0x68, 0x39, 0x27, 0x81 };
+
+void branch_to_self(void) __attribute__ ((noreturn));
+
+/*
+ * This function will put core in infinite loop.
+ * This will be called when the ESBC can not proceed further due
+ * to some unknown errors.
+ */
+void branch_to_self(void)
+{
+	printf("Core is in infinite loop due to errors.\n");
+self:
+	goto self;
+}
+
+#if defined(CONFIG_FSL_ISBC_KEY_EXT)
+static u32 check_ie(struct fsl_secboot_img_priv *img)
+{
+	if (img->hdr.ie_flag)
+		return 1;
+
+	return 0;
+}
+
+/* This function returns the CSF Header Address of uboot
+ * For MPC85xx based platforms, the LAW mapping for NOR
+ * flash changes in uboot code. Hence the offset needs
+ * to be calculated and added to the new NOR flash base
+ * address
+ */
+#if defined(CONFIG_MPC85xx)
+int get_csf_base_addr(ulong *csf_addr, ulong *flash_base_addr)
+{
+	struct ccsr_gur __iomem *gur = (void *)(CONFIG_SYS_MPC85xx_GUTS_ADDR);
+	u32 csf_hdr_addr = in_be32(&gur->scratchrw[0]);
+	u32 csf_flash_offset = csf_hdr_addr & ~(CONFIG_SYS_PBI_FLASH_BASE);
+	ulong flash_addr, addr;
+	int found = 0;
+	int i = 0;
+
+	for (i = 0; i < CONFIG_SYS_MAX_FLASH_BANKS; i++) {
+		flash_addr = flash_info[i].start[0];
+		addr = flash_info[i].start[0] + csf_flash_offset;
+		if (memcmp((u8 *)addr, barker_code, ESBC_BARKER_LEN) == 0) {
+			debug("Barker found on addr %lx\n", addr);
+			found = 1;
+			break;
+		}
+	}
+
+	if (!found)
+		return -1;
+
+	*csf_addr = addr;
+	*flash_base_addr = flash_addr;
+
+	return 0;
+}
+#else
+/* For platforms like LS1020, correct flash address is present in
+ * the header. So the function reqturns flash base address as 0
+ */
+int get_csf_base_addr(ulong *csf_addr, ulong *flash_base_addr)
+{
+	struct ccsr_gur __iomem *gur = (void *)(CONFIG_SYS_FSL_GUTS_ADDR);
+	u32 csf_hdr_addr = in_be32(&gur->scratchrw[0]);
+
+	if (memcmp((u8 *)csf_hdr_addr, barker_code, ESBC_BARKER_LEN))
+		return -1;
+
+	*csf_addr = csf_hdr_addr;
+	*flash_base_addr = 0;
+	return 0;
+}
+#endif
+
+static int get_ie_info_addr(ulong *ie_addr)
+{
+	struct fsl_secboot_img_hdr *hdr;
+	struct fsl_secboot_sg_table *sg_tbl;
+	ulong flash_base_addr, csf_addr;
+
+	if (get_csf_base_addr(&csf_addr, &flash_base_addr))
+		return -1;
+
+	hdr = (struct fsl_secboot_img_hdr *)csf_addr;
+
+	/* For SoC's with Trust Architecture v1 with corenet bus
+	 * the sg table field in CSF header has absolute address
+	 * for sg table in memory. In other Trust Architecture,
+	 * this field specifies the offset of sg table from the
+	 * base address of CSF Header
+	 */
+#if defined(CONFIG_FSL_TRUST_ARCH_v1) && defined(CONFIG_FSL_CORENET)
+	sg_tbl = (struct fsl_secboot_sg_table *)
+		 (((ulong)hdr->psgtable & ~(CONFIG_SYS_PBI_FLASH_BASE)) +
+		  flash_base_addr);
+#else
+	sg_tbl = (struct fsl_secboot_sg_table *)(csf_addr +
+						 (ulong)hdr->psgtable);
+#endif
+
+	/* IE Key Table is the first entry in the SG Table */
+#if defined(CONFIG_MPC85xx)
+	*ie_addr = (sg_tbl->src_addr & ~(CONFIG_SYS_PBI_FLASH_BASE)) +
+		   flash_base_addr;
+#else
+	*ie_addr = sg_tbl->src_addr;
+#endif
+
+	debug("IE Table address is %lx\n", *ie_addr);
+	return 0;
+}
+
+#endif
+
+#ifdef CONFIG_KEY_REVOCATION
+/* This function checks srk_table_flag in header and set/reset srk_flag.*/
+static u32 check_srk(struct fsl_secboot_img_priv *img)
+{
+	if (img->hdr.len_kr.srk_table_flag & SRK_FLAG)
+		return 1;
+
+	return 0;
+}
+
+/* This function returns ospr's key_revoc values.*/
+static u32 get_key_revoc(void)
+{
+	struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
+	return (sfp_in32(&sfp_regs->ospr) & OSPR_KEY_REVOC_MASK) >>
+		OSPR_KEY_REVOC_SHIFT;
+}
+
+/* This function checks if selected key is revoked or not.*/
+static u32 is_key_revoked(u32 keynum, u32 rev_flag)
+{
+	if (keynum == UNREVOCABLE_KEY)
+		return 0;
+
+	if ((u32)(1 << (ALIGN_REVOC_KEY - keynum)) & rev_flag)
+		return 1;
+
+	return 0;
+}
+
+/* It validates srk_table key lengths.*/
+static u32 validate_srk_tbl(struct srk_table *tbl, u32 num_entries)
+{
+	int i = 0;
+	for (i = 0; i < num_entries; i++) {
+		if (!((tbl[i].key_len == 2 * KEY_SIZE_BYTES/4) ||
+		      (tbl[i].key_len == 2 * KEY_SIZE_BYTES/2) ||
+		      (tbl[i].key_len == 2 * KEY_SIZE_BYTES)))
+			return ERROR_ESBC_CLIENT_HEADER_INV_SRK_ENTRY_KEYLEN;
+	}
+	return 0;
+}
+#endif
+
+/* This function return length of public key.*/
+static inline u32 get_key_len(struct fsl_secboot_img_priv *img)
+{
+	return img->key_len;
+}
+
+/*
+ * Handles the ESBC uboot client header verification failure.
+ * This  function  handles all the errors which might occur in the
+ * parsing and checking of ESBC uboot client header. It will also
+ * set the error bits in the SEC_MON.
+ */
+static void fsl_secboot_header_verification_failure(void)
+{
+	struct ccsr_sec_mon_regs *sec_mon_regs = (void *)
+						(CONFIG_SYS_SEC_MON_ADDR);
+	struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
+	u32 sts = sec_mon_in32(&sec_mon_regs->hp_stat);
+
+	/* 29th bit of OSPR is ITS */
+	u32 its = sfp_in32(&sfp_regs->ospr) >> 2;
+
+	/*
+	 * Read the SEC_MON status register
+	 * Read SSM_ST field
+	 */
+	sts = sec_mon_in32(&sec_mon_regs->hp_stat);
+	if ((sts & HPSR_SSM_ST_MASK) == HPSR_SSM_ST_TRUST) {
+		if (its == 1)
+			change_sec_mon_state(HPSR_SSM_ST_TRUST,
+					     HPSR_SSM_ST_SOFT_FAIL);
+		else
+			change_sec_mon_state(HPSR_SSM_ST_TRUST,
+					     HPSR_SSM_ST_NON_SECURE);
+	}
+
+	printf("Generating reset request\n");
+	do_reset(NULL, 0, 0, NULL);
+}
+
+/*
+ * Handles the ESBC uboot client image verification failure.
+ * This  function  handles all the errors which might occur in the
+ * public key hash comparison and signature verification of
+ * ESBC uboot client image. It will also
+ * set the error bits in the SEC_MON.
+ */
+static void fsl_secboot_image_verification_failure(void)
+{
+	struct ccsr_sec_mon_regs *sec_mon_regs = (void *)
+						(CONFIG_SYS_SEC_MON_ADDR);
+	struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
+	u32 sts = sec_mon_in32(&sec_mon_regs->hp_stat);
+
+	u32 its = sfp_in32(&sfp_regs->ospr) & ITS_MASK >> ITS_BIT;
+
+	/*
+	 * Read the SEC_MON status register
+	 * Read SSM_ST field
+	 */
+	sts = sec_mon_in32(&sec_mon_regs->hp_stat);
+	if ((sts & HPSR_SSM_ST_MASK) == HPSR_SSM_ST_TRUST) {
+		if (its == 1) {
+			change_sec_mon_state(HPSR_SSM_ST_TRUST,
+					     HPSR_SSM_ST_SOFT_FAIL);
+
+			printf("Generating reset request\n");
+			do_reset(NULL, 0, 0, NULL);
+		} else {
+			change_sec_mon_state(HPSR_SSM_ST_TRUST,
+					     HPSR_SSM_ST_NON_SECURE);
+		}
+	}
+}
+
+static void fsl_secboot_bootscript_parse_failure(void)
+{
+	fsl_secboot_header_verification_failure();
+}
+
+/*
+ * Handles the errors in esbc boot.
+ * This  function  handles all the errors which might occur in the
+ * esbc boot phase. It will call the appropriate api to log the
+ * errors and set the error bits in the SEC_MON.
+ */
+void fsl_secboot_handle_error(int error)
+{
+	const struct fsl_secboot_errcode *e;
+
+	for (e = fsl_secboot_errcodes; e->errcode != ERROR_ESBC_CLIENT_MAX;
+		e++) {
+		if (e->errcode == error)
+			printf("ERROR :: %x :: %s\n", error, e->name);
+	}
+
+	switch (error) {
+	case ERROR_ESBC_CLIENT_HEADER_BARKER:
+	case ERROR_ESBC_CLIENT_HEADER_IMG_SIZE:
+	case ERROR_ESBC_CLIENT_HEADER_KEY_LEN:
+	case ERROR_ESBC_CLIENT_HEADER_SIG_LEN:
+	case ERROR_ESBC_CLIENT_HEADER_KEY_LEN_NOT_TWICE_SIG_LEN:
+	case ERROR_ESBC_CLIENT_HEADER_KEY_MOD_1:
+	case ERROR_ESBC_CLIENT_HEADER_KEY_MOD_2:
+	case ERROR_ESBC_CLIENT_HEADER_SIG_KEY_MOD:
+	case ERROR_ESBC_CLIENT_HEADER_SG_ESBC_EP:
+	case ERROR_ESBC_CLIENT_HEADER_SG_ENTIRES_BAD:
+#ifdef CONFIG_KEY_REVOCATION
+	case ERROR_ESBC_CLIENT_HEADER_KEY_REVOKED:
+	case ERROR_ESBC_CLIENT_HEADER_INVALID_SRK_NUM_ENTRY:
+	case ERROR_ESBC_CLIENT_HEADER_INVALID_KEY_NUM:
+	case ERROR_ESBC_CLIENT_HEADER_INV_SRK_ENTRY_KEYLEN:
+#endif
+#if defined(CONFIG_FSL_ISBC_KEY_EXT)
+	/*@fallthrough@*/
+	case ERROR_ESBC_CLIENT_HEADER_IE_KEY_REVOKED:
+	case ERROR_ESBC_CLIENT_HEADER_INVALID_IE_NUM_ENTRY:
+	case ERROR_ESBC_CLIENT_HEADER_INVALID_IE_KEY_NUM:
+	case ERROR_ESBC_CLIENT_HEADER_INV_IE_ENTRY_KEYLEN:
+	case ERROR_IE_TABLE_NOT_FOUND:
+#endif
+		fsl_secboot_header_verification_failure();
+		break;
+	case ERROR_ESBC_SEC_RESET:
+	case ERROR_ESBC_SEC_DEQ:
+	case ERROR_ESBC_SEC_ENQ:
+	case ERROR_ESBC_SEC_DEQ_TO:
+	case ERROR_ESBC_SEC_JOBQ_STATUS:
+	case ERROR_ESBC_CLIENT_HASH_COMPARE_KEY:
+	case ERROR_ESBC_CLIENT_HASH_COMPARE_EM:
+		fsl_secboot_image_verification_failure();
+		break;
+	case ERROR_ESBC_MISSING_BOOTM:
+		fsl_secboot_bootscript_parse_failure();
+		break;
+	case ERROR_ESBC_WRONG_CMD:
+	default:
+		branch_to_self();
+		break;
+	}
+}
+
+static void fsl_secblk_handle_error(int error)
+{
+	switch (error) {
+	case ERROR_ESBC_SEC_ENQ:
+		fsl_secboot_handle_error(ERROR_ESBC_SEC_ENQ);
+		break;
+	case ERROR_ESBC_SEC_DEQ:
+		fsl_secboot_handle_error(ERROR_ESBC_SEC_DEQ);
+		break;
+	case ERROR_ESBC_SEC_DEQ_TO:
+		fsl_secboot_handle_error(ERROR_ESBC_SEC_DEQ_TO);
+		break;
+	default:
+		printf("Job Queue Output status %x\n", error);
+		fsl_secboot_handle_error(ERROR_ESBC_SEC_JOBQ_STATUS);
+		break;
+	}
+}
+
+/*
+ * Calculate hash of key obtained via offset present in ESBC uboot
+ * client hdr. This function calculates the hash of key which is obtained
+ * through offset present in ESBC uboot client header.
+ */
+static int calc_img_key_hash(struct fsl_secboot_img_priv *img)
+{
+	struct hash_algo *algo;
+	void *ctx;
+	int i, srk = 0;
+	int ret = 0;
+	const char *algo_name = "sha256";
+
+	/* Calculate hash of the esbc key */
+	ret = hash_progressive_lookup_algo(algo_name, &algo);
+	if (ret)
+		return ret;
+
+	ret = algo->hash_init(algo, &ctx);
+	if (ret)
+		return ret;
+
+	/* Update hash for ESBC key */
+#ifdef CONFIG_KEY_REVOCATION
+	if (check_srk(img)) {
+		ret = algo->hash_update(algo, ctx,
+			(u8 *)(img->ehdrloc + img->hdr.srk_tbl_off),
+			img->hdr.len_kr.num_srk * sizeof(struct srk_table), 1);
+		srk = 1;
+	}
+#endif
+	if (!srk)
+		ret = algo->hash_update(algo, ctx,
+			img->img_key, img->key_len, 1);
+	if (ret)
+		return ret;
+
+	/* Copy hash at destination buffer */
+	ret = algo->hash_finish(algo, ctx, hash_val, algo->digest_size);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < SHA256_BYTES; i++)
+		img->img_key_hash[i] = hash_val[i];
+
+	return 0;
+}
+
+/*
+ * Calculate hash of ESBC hdr and ESBC. This function calculates the
+ * single hash of ESBC header and ESBC image. If SG flag is on, all
+ * SG entries are also hashed alongwith the complete SG table.
+ */
+static int calc_esbchdr_esbc_hash(struct fsl_secboot_img_priv *img)
+{
+	struct hash_algo *algo;
+	void *ctx;
+	int ret = 0;
+	int key_hash = 0;
+	const char *algo_name = "sha256";
+
+	/* Calculate the hash of the ESBC */
+	ret = hash_progressive_lookup_algo(algo_name, &algo);
+	if (ret)
+		return ret;
+
+	ret = algo->hash_init(algo, &ctx);
+	/* Copy hash at destination buffer */
+	if (ret)
+		return ret;
+
+	/* Update hash for CSF Header */
+	ret = algo->hash_update(algo, ctx,
+		(u8 *)&img->hdr, sizeof(struct fsl_secboot_img_hdr), 0);
+	if (ret)
+		return ret;
+
+	/* Update the hash with that of srk table if srk flag is 1
+	 * If IE Table is selected, key is not added in the hash
+	 * If neither srk table nor IE key table available, add key
+	 * from header in the hash calculation
+	 */
+#ifdef CONFIG_KEY_REVOCATION
+	if (check_srk(img)) {
+		ret = algo->hash_update(algo, ctx,
+			(u8 *)(img->ehdrloc + img->hdr.srk_tbl_off),
+			img->hdr.len_kr.num_srk * sizeof(struct srk_table), 0);
+		key_hash = 1;
+	}
+#endif
+#if defined(CONFIG_FSL_ISBC_KEY_EXT)
+	if (!key_hash && check_ie(img))
+		key_hash = 1;
+#endif
+	if (!key_hash)
+		ret = algo->hash_update(algo, ctx,
+			img->img_key, img->hdr.key_len, 0);
+	if (ret)
+		return ret;
+
+	/* Update hash for actual Image */
+	ret = algo->hash_update(algo, ctx,
+			(u8 *)img->hdr.pimg, img->hdr.img_size, 1);
+	if (ret)
+		return ret;
+
+	/* Copy hash at destination buffer */
+	ret = algo->hash_finish(algo, ctx, hash_val, algo->digest_size);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/*
+ * Construct encoded hash EM' wrt PKCSv1.5. This function calculates the
+ * pointers for padding, DER value and hash. And finally, constructs EM'
+ * which includes hash of complete CSF header and ESBC image. If SG flag
+ * is on, hash of SG table and entries is also included.
+ */
+static void construct_img_encoded_hash_second(struct fsl_secboot_img_priv *img)
+{
+	/*
+	 * RSA PKCSv1.5 encoding format for encoded message is below
+	 * EM = 0x0 || 0x1 || PS || 0x0 || DER || Hash
+	 * PS is Padding String
+	 * DER is DER value for SHA-256
+	 * Hash is SHA-256 hash
+	 * *********************************************************
+	 * representative points to first byte of EM initially and is
+	 * filled with 0x0
+	 * representative is incremented by 1 and second byte is filled
+	 * with 0x1
+	 * padding points to third byte of EM
+	 * digest points to full length of EM - 32 bytes
+	 * hash_id (DER value) points to 19 bytes before pDigest
+	 * separator is one byte which separates padding and DER
+	 */
+
+	size_t len;
+	u8 *representative;
+	u8 *padding, *digest;
+	u8 *hash_id, *separator;
+	int i;
+
+	len = (get_key_len(img) / 2) - 1;
+	representative = img->img_encoded_hash_second;
+	representative[0] = 0;
+	representative[1] = 1;  /* block type 1 */
+
+	padding = &representative[2];
+	digest = &representative[1] + len - 32;
+	hash_id = digest - sizeof(hash_identifier);
+	separator = hash_id - 1;
+
+	/* fill padding area pointed by padding with 0xff */
+	memset(padding, 0xff, separator - padding);
+
+	/* fill byte pointed by separator */
+	*separator = 0;
+
+	/* fill SHA-256 DER value  pointed by HashId */
+	memcpy(hash_id, hash_identifier, sizeof(hash_identifier));
+
+	/* fill hash pointed by Digest */
+	for (i = 0; i < SHA256_BYTES; i++)
+		digest[i] = hash_val[i];
+}
+
+/*
+ * Reads and validates the ESBC client header.
+ * This function reads key and signature from the ESBC client header.
+ * If Scatter/Gather flag is on, lengths and offsets of images
+ * present as SG entries are also read. This function also checks
+ * whether the header is valid or not.
+ */
+static int read_validate_esbc_client_header(struct fsl_secboot_img_priv *img)
+{
+	char buf[20];
+	struct fsl_secboot_img_hdr *hdr = &img->hdr;
+	void *esbc = (u8 *)img->ehdrloc;
+	u8 *k, *s;
+#ifdef CONFIG_KEY_REVOCATION
+	u32 ret;
+	u32 key_num, key_revoc_flag, size;
+#endif
+#if defined(CONFIG_FSL_ISBC_KEY_EXT)
+	struct ie_key_info *ie_info;
+	u32 ie_num, ie_revoc_flag, ie_key_len;
+#endif
+	int  key_found = 0;
+
+	/* check barker code */
+	if (memcmp(hdr->barker, barker_code, ESBC_BARKER_LEN))
+		return ERROR_ESBC_CLIENT_HEADER_BARKER;
+
+	sprintf(buf, "%p", hdr->pimg);
+	setenv("img_addr", buf);
+
+	if (!hdr->img_size)
+		return ERROR_ESBC_CLIENT_HEADER_IMG_SIZE;
+
+	/* Key checking*/
+#ifdef CONFIG_KEY_REVOCATION
+	if (check_srk(img)) {
+		if ((hdr->len_kr.num_srk == 0) ||
+		    (hdr->len_kr.num_srk > MAX_KEY_ENTRIES))
+			return ERROR_ESBC_CLIENT_HEADER_INVALID_SRK_NUM_ENTRY;
+
+		key_num = hdr->len_kr.srk_sel;
+		if (key_num == 0 || key_num > hdr->len_kr.num_srk)
+			return ERROR_ESBC_CLIENT_HEADER_INVALID_KEY_NUM;
+
+		/* Get revoc key from sfp */
+		key_revoc_flag = get_key_revoc();
+		ret = is_key_revoked(key_num, key_revoc_flag);
+		if (ret)
+			return ERROR_ESBC_CLIENT_HEADER_KEY_REVOKED;
+
+		size = hdr->len_kr.num_srk * sizeof(struct srk_table);
+
+		memcpy(&img->srk_tbl, esbc + hdr->srk_tbl_off, size);
+
+		ret = validate_srk_tbl(img->srk_tbl, hdr->len_kr.num_srk);
+
+		if (ret != 0)
+			return ret;
+
+		img->key_len = img->srk_tbl[key_num - 1].key_len;
+
+		memcpy(&img->img_key, &(img->srk_tbl[key_num - 1].pkey),
+		       img->key_len);
+
+		key_found = 1;
+	}
+#endif
+
+#if defined(CONFIG_FSL_ISBC_KEY_EXT)
+	if (!key_found && check_ie(img)) {
+		if (get_ie_info_addr(&img->ie_addr))
+			return ERROR_IE_TABLE_NOT_FOUND;
+		ie_info = (struct ie_key_info *)img->ie_addr;
+		if (ie_info->num_keys == 0 || ie_info->num_keys > 32)
+			return ERROR_ESBC_CLIENT_HEADER_INVALID_IE_NUM_ENTRY;
+
+		ie_num = hdr->ie_key_sel;
+		if (ie_num == 0 || ie_num > ie_info->num_keys)
+			return ERROR_ESBC_CLIENT_HEADER_INVALID_IE_KEY_NUM;
+
+		ie_revoc_flag = ie_info->key_revok;
+		if ((u32)(1 << (ie_num - 1)) & ie_revoc_flag)
+			return ERROR_ESBC_CLIENT_HEADER_IE_KEY_REVOKED;
+
+		ie_key_len = ie_info->ie_key_tbl[ie_num - 1].key_len;
+
+		if (!((ie_key_len == 2 * KEY_SIZE_BYTES / 4) ||
+		      (ie_key_len == 2 * KEY_SIZE_BYTES / 2) ||
+		      (ie_key_len == 2 * KEY_SIZE_BYTES)))
+			return ERROR_ESBC_CLIENT_HEADER_INV_IE_ENTRY_KEYLEN;
+
+		memcpy(&img->img_key, &(ie_info->ie_key_tbl[ie_num - 1].pkey),
+		       ie_key_len);
+
+		img->key_len = ie_key_len;
+		key_found = 1;
+	}
+#endif
+
+	if (key_found == 0) {
+		/* check key length */
+		if (!((hdr->key_len == 2 * KEY_SIZE_BYTES / 4) ||
+		      (hdr->key_len == 2 * KEY_SIZE_BYTES / 2) ||
+		      (hdr->key_len == 2 * KEY_SIZE_BYTES)))
+			return ERROR_ESBC_CLIENT_HEADER_KEY_LEN;
+
+		memcpy(&img->img_key, esbc + hdr->pkey, hdr->key_len);
+
+		img->key_len = hdr->key_len;
+
+		key_found = 1;
+	}
+
+	/* check signaure */
+	if (get_key_len(img) == 2 * hdr->sign_len) {
+		/* check signature length */
+		if (!((hdr->sign_len == KEY_SIZE_BYTES / 4) ||
+		      (hdr->sign_len == KEY_SIZE_BYTES / 2) ||
+		      (hdr->sign_len == KEY_SIZE_BYTES)))
+			return ERROR_ESBC_CLIENT_HEADER_SIG_LEN;
+	} else {
+		return ERROR_ESBC_CLIENT_HEADER_KEY_LEN_NOT_TWICE_SIG_LEN;
+	}
+
+	memcpy(&img->img_sign, esbc + hdr->psign, hdr->sign_len);
+
+	/* No SG support */
+	if (hdr->sg_flag)
+		return ERROR_ESBC_CLIENT_HEADER_SG;
+
+	/* modulus most significant bit should be set */
+	k = (u8 *)&img->img_key;
+
+	if ((k[0] & 0x80) == 0)
+		return ERROR_ESBC_CLIENT_HEADER_KEY_MOD_1;
+
+	/* modulus value should be odd */
+	if ((k[get_key_len(img) / 2 - 1] & 0x1) == 0)
+		return ERROR_ESBC_CLIENT_HEADER_KEY_MOD_2;
+
+	/* Check signature value < modulus value */
+	s = (u8 *)&img->img_sign;
+
+	if (!(memcmp(s, k, hdr->sign_len) < 0))
+		return ERROR_ESBC_CLIENT_HEADER_SIG_KEY_MOD;
+
+	return ESBC_VALID_HDR;
+}
+
+static inline int str2longbe(const char *p, ulong *num)
+{
+	char *endptr;
+	ulong tmp;
+
+	if (!p) {
+		return 0;
+	} else {
+		tmp = simple_strtoul(p, &endptr, 16);
+		if (sizeof(ulong) == 4)
+			*num = cpu_to_be32(tmp);
+		else
+			*num = cpu_to_be64(tmp);
+	}
+
+	return *p != '\0' && *endptr == '\0';
+}
+
+int fsl_secboot_validate(cmd_tbl_t *cmdtp, int flag, int argc,
+		char * const argv[])
+{
+	struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
+	ulong hash[SHA256_BYTES/sizeof(ulong)];
+	char hash_str[NUM_HEX_CHARS + 1];
+	ulong addr = simple_strtoul(argv[1], NULL, 16);
+	struct fsl_secboot_img_priv *img;
+	struct fsl_secboot_img_hdr *hdr;
+	void *esbc;
+	int ret, i, hash_cmd = 0;
+	u32 srk_hash[8];
+	uint32_t key_len;
+	struct key_prop prop;
+#if !defined(USE_HOSTCC)
+	struct udevice *mod_exp_dev;
+#endif
+
+	if (argc == 3) {
+		char *cp = argv[2];
+		int i = 0;
+
+		if (*cp == '0' && *(cp + 1) == 'x')
+			cp += 2;
+
+		/* The input string expected is in hex, where
+		 * each 4 bits would be represented by a hex
+		 * sha256 hash is 256 bits long, which would mean
+		 * num of characters = 256 / 4
+		 */
+		if (strlen(cp) != SHA256_NIBBLES) {
+			printf("%s is not a 256 bits hex string as expected\n",
+			       argv[2]);
+			return -1;
+		}
+
+		for (i = 0; i < sizeof(hash)/sizeof(ulong); i++) {
+			strncpy(hash_str, cp + (i * NUM_HEX_CHARS),
+				NUM_HEX_CHARS);
+			hash_str[NUM_HEX_CHARS] = '\0';
+			if (!str2longbe(hash_str, &hash[i])) {
+				printf("%s is not a 256 bits hex string ",
+				       argv[2]);
+				return -1;
+			}
+		}
+
+		hash_cmd = 1;
+	}
+
+	img = malloc(sizeof(struct fsl_secboot_img_priv));
+
+	if (!img)
+		return -1;
+
+	memset(img, 0, sizeof(struct fsl_secboot_img_priv));
+
+	hdr = &img->hdr;
+	img->ehdrloc = addr;
+	esbc = (u8 *)img->ehdrloc;
+
+	memcpy(hdr, esbc, sizeof(struct fsl_secboot_img_hdr));
+
+	/* read and validate esbc header */
+	ret = read_validate_esbc_client_header(img);
+
+	if (ret != ESBC_VALID_HDR) {
+		fsl_secboot_handle_error(ret);
+		goto exit;
+	}
+
+	/* SRKH present in SFP */
+	for (i = 0; i < NUM_SRKH_REGS; i++)
+		srk_hash[i] = srk_in32(&sfp_regs->srk_hash[i]);
+
+	/*
+	 * Calculate hash of key obtained via offset present in
+	 * ESBC uboot client hdr
+	 */
+	ret = calc_img_key_hash(img);
+	if (ret) {
+		fsl_secblk_handle_error(ret);
+		goto exit;
+	}
+
+	/* Compare hash obtained above with SRK hash present in SFP */
+	if (hash_cmd)
+		ret = memcmp(&hash, &img->img_key_hash, SHA256_BYTES);
+	else
+		ret = memcmp(srk_hash, img->img_key_hash, SHA256_BYTES);
+
+#if defined(CONFIG_FSL_ISBC_KEY_EXT)
+	if (!hash_cmd && check_ie(img))
+		ret = 0;
+#endif
+
+	if (ret != 0) {
+		fsl_secboot_handle_error(ERROR_ESBC_CLIENT_HASH_COMPARE_KEY);
+		goto exit;
+	}
+
+	ret = calc_esbchdr_esbc_hash(img);
+	if (ret) {
+		fsl_secblk_handle_error(ret);
+		goto exit;
+	}
+
+	/* Construct encoded hash EM' wrt PKCSv1.5 */
+	construct_img_encoded_hash_second(img);
+
+	/* Fill prop structure for public key */
+	memset(&prop, 0, sizeof(struct key_prop));
+	key_len = get_key_len(img) / 2;
+	prop.modulus = img->img_key;
+	prop.public_exponent = img->img_key + key_len;
+	prop.num_bits = key_len * 8;
+	prop.exp_len = key_len;
+
+	ret = uclass_get_device(UCLASS_MOD_EXP, 0, &mod_exp_dev);
+	if (ret) {
+		printf("RSA: Can't find Modular Exp implementation\n");
+		return -EINVAL;
+	}
+
+	ret = rsa_mod_exp(mod_exp_dev, img->img_sign, img->hdr.sign_len,
+			  &prop, img->img_encoded_hash);
+	if (ret) {
+		fsl_secblk_handle_error(ret);
+		goto exit;
+	}
+
+	/*
+	 * compare the encoded messages EM' and EM wrt RSA PKCSv1.5
+	 * memcmp returns zero on success
+	 * memcmp returns non-zero on failure
+	 */
+	ret = memcmp(&img->img_encoded_hash_second, &img->img_encoded_hash,
+		img->hdr.sign_len);
+
+	if (ret) {
+		fsl_secboot_handle_error(ERROR_ESBC_CLIENT_HASH_COMPARE_EM);
+		goto exit;
+	}
+
+	printf("esbc_validate command successful\n");
+
+exit:
+	return 0;
+}