[U-Boot] [RFC PATCH 2/2] zynq: Add support for loading secure images
Siva Durga Prasad Paladugu
siva.durga.paladugu at xilinx.com
Mon Apr 2 06:15:04 UTC 2018
This patch adds support to load secure images
secure image is an image which is authenticated
or encrypted or both autheticated and encrypted
image in xilinx boot image(BOOT.BIN) format. The
secure image has to be created using xilinx bootgen
tool.
Signed-off-by: Siva Durga Prasad Paladugu <sivadur at xilinx.com>
---
board/xilinx/zynq/Kconfig | 12 +
board/xilinx/zynq/Makefile | 4 +
board/xilinx/zynq/cmds.c | 602 +++++++++++++++++++++++++++++++++++++++++++
include/u-boot/rsa-mod-exp.h | 4 +
lib/rsa/rsa-mod-exp.c | 51 ++++
5 files changed, 673 insertions(+)
create mode 100644 board/xilinx/zynq/cmds.c
diff --git a/board/xilinx/zynq/Kconfig b/board/xilinx/zynq/Kconfig
index f8f8a7f..54d71dc 100644
--- a/board/xilinx/zynq/Kconfig
+++ b/board/xilinx/zynq/Kconfig
@@ -11,4 +11,16 @@ config CMD_ZYNQ_AES
Decrypts the encrypted image present in source address
and places the decrypted image at destination address.
+config CMD_ZYNQ
+ bool "Enable ZynqMP specific commands"
+ default y
+ depends on CMD_ZYNQ_AES
+ help
+ Enable Zynq specific commands like "zynq rsa"
+ which is used for zynq secure image verification.
+ The secure image is a xilinx specific BOOT.BIN with
+ either authentication or encryption or both encryption
+ and authentication feature enabled while generating
+ BOOT.BIN using Xilinx bootgen tool.
+
endif
diff --git a/board/xilinx/zynq/Makefile b/board/xilinx/zynq/Makefile
index 7de0212..07a5bc5 100644
--- a/board/xilinx/zynq/Makefile
+++ b/board/xilinx/zynq/Makefile
@@ -20,6 +20,10 @@ $(warning Put custom ps7_init_gpl.c/h to board/xilinx/zynq/custom_hw_platform/))
endif
endif
+ifndef CONFIG_SPL_BUILD
+obj-$(CONFIG_CMD_ZYNQ) += cmds.o
+endif
+
obj-$(CONFIG_SPL_BUILD) += $(init-objs)
# Suppress "warning: function declaration isn't a prototype"
diff --git a/board/xilinx/zynq/cmds.c b/board/xilinx/zynq/cmds.c
new file mode 100644
index 0000000..9365557
--- /dev/null
+++ b/board/xilinx/zynq/cmds.c
@@ -0,0 +1,602 @@
+/*
+ * Copyright (C) 2018 Xilinx, Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/hardware.h>
+#include <asm/arch/sys_proto.h>
+#include <u-boot/md5.h>
+#include <u-boot/rsa.h>
+#include <u-boot/rsa-mod-exp.h>
+#include <u-boot/sha256.h>
+#include <spi_flash.h>
+#include <zynqpl.h>
+#include <fpga.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define ZYNQ_IMAGE_PHDR_OFFSET 0x09C
+#define ZYNQ_IMAGE_FSBL_LEN_OFFSET 0x040
+
+#define ZYNQ_PART_HDR_CHKSUM_WORD_COUNT 0x0F
+#define ZYNQ_PART_HDR_WORD_COUNT 0x10
+
+#define ZYNQ_EFUSE_RSA_ENABLE_MASK 0x400
+
+#define ZYNQ_ATTRIBUTE_PL_IMAGE_MASK 0x20
+#define ZYNQ_ATTRIBUTE_CHECKSUM_TYPE_MASK 0x7000
+#define ZYNQ_ATTRIBUTE_RSA_PRESENT_MASK 0x8000
+#define ZYNQ_ATTRIBUTE_RSA_PART_OWNER_MASK 0x30000
+
+#define ZYNQ_MAX_PARTITION_NUMBER 0xE
+
+#define ZYNQ_RSA_MODULAR_SIZE 256
+#define ZYNQ_RSA_MODULAR_EXT_SIZE 256
+#define ZYNQ_RSA_EXPO_SIZE 64
+#define ZYNQ_RSA_SPK_SIGNATURE_SIZE 256
+#define ZYNQ_RSA_PARTITION_SIGNATURE_SIZE 256
+#define ZYNQ_RSA_SIGNATURE_SIZE 0x6C0
+#define ZYNQ_RSA_HEADER_SIZE 4
+#define ZYNQ_RSA_MAGIC_WORD_SIZE 60
+#define ZYNQ_RSA_PART_OWNER_UBOOT 1
+#define ZYNQ_RSA_ALIGN_PPK_START 64
+
+#define WORD_LENGTH_SHIFT 2
+#define ZYNQ_MAXIMUM_IMAGE_WORD_LEN 0x40000000
+
+#define MD5_CHECKSUM_SIZE 16
+
+static u8 *ppkmodular;
+static u8 *ppkmodularex;
+static u32 ppkexp;
+
+struct partition_hdr {
+ u32 imagewordlen; /* 0x0 */
+ u32 datawordlen; /* 0x4 */
+ u32 partitionwordlen; /* 0x8 */
+ u32 loadaddr; /* 0xC */
+ u32 execaddr; /* 0x10 */
+ u32 partitionstart; /* 0x14 */
+ u32 partitionattr; /* 0x18 */
+ u32 sectioncount; /* 0x1C */
+ u32 checksumoffset; /* 0x20 */
+ u32 pads1[1];
+ u32 acoffset; /* 0x28 */
+ u32 pads2[4];
+ u32 checksum; /* 0x3C */
+};
+
+struct zynq_rsa_public_key {
+ uint len; /* Length of modulus[] in number of u32 */
+ u32 n0inv; /* -1 / modulus[0] mod 2^32 */
+ u32 *modulus; /* modulus as little endian array */
+ u32 *rr; /* R^2 as little endian array */
+};
+
+struct partition_hdr part_hdr[ZYNQ_MAX_PARTITION_NUMBER];
+
+struct headerarray {
+ u32 fields[16];
+};
+
+struct zynq_rsa_public_key public_key;
+
+static u32 fsbl_len;
+
+/*
+ * Check whether the given partition is last partition or not
+ */
+static int zynq_islastpartition(struct headerarray *head)
+{
+ int index;
+
+ debug("%s\n", __func__);
+ if (head->fields[ZYNQ_PART_HDR_CHKSUM_WORD_COUNT] != 0xFFFFFFFF)
+ return -1;
+
+ for (index = 0; index < ZYNQ_PART_HDR_WORD_COUNT - 1; index++) {
+ if (head->fields[index] != 0x0)
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * Get the partition count from the partition header
+ */
+static int zynq_get_part_count(struct partition_hdr *part_hdr_info)
+{
+ u32 count = 0;
+ struct headerarray *hap;
+
+ debug("%s\n", __func__);
+
+ for (count = 0; count < ZYNQ_MAX_PARTITION_NUMBER; count++) {
+ hap = (struct headerarray *)&part_hdr_info[count];
+ if (zynq_islastpartition(hap) != -1)
+ break;
+ }
+
+ return count;
+}
+
+/*
+ * Get the partition info of all the partitions available.
+ */
+static int zynq_get_partition_info(u32 image_base_addr)
+{
+ u32 parthdroffset;
+
+ fsbl_len = *((u32 *)(image_base_addr + ZYNQ_IMAGE_FSBL_LEN_OFFSET));
+
+ parthdroffset = *((u32 *)(image_base_addr + ZYNQ_IMAGE_PHDR_OFFSET));
+
+ parthdroffset += image_base_addr;
+
+ memcpy(&part_hdr[0], (u32 *)parthdroffset,
+ (sizeof(struct partition_hdr) * ZYNQ_MAX_PARTITION_NUMBER));
+
+ return 0;
+}
+
+/*
+ * Check whether the partition header is valid or not
+ */
+static int zynq_validate_hdr(struct partition_hdr *header)
+{
+ struct headerarray *hap;
+ u32 index;
+ u32 checksum;
+
+ debug("%s\n", __func__);
+
+ hap = (struct headerarray *)header;
+
+ for (index = 0; index < ZYNQ_PART_HDR_WORD_COUNT; index++) {
+ if (hap->fields[index] != 0x0)
+ break;
+ }
+ if (index == ZYNQ_PART_HDR_WORD_COUNT)
+ return -1;
+
+ checksum = 0;
+ for (index = 0; index < ZYNQ_PART_HDR_CHKSUM_WORD_COUNT; index++)
+ checksum += hap->fields[index];
+
+ checksum ^= 0xFFFFFFFF;
+
+ if (hap->fields[ZYNQ_PART_HDR_CHKSUM_WORD_COUNT] != checksum) {
+ printf("Error: Checksum 0x%8.8x != 0x%8.8x\r\n",
+ checksum, hap->fields[ZYNQ_PART_HDR_CHKSUM_WORD_COUNT]);
+ return -1;
+ }
+
+ if (header->imagewordlen > ZYNQ_MAXIMUM_IMAGE_WORD_LEN) {
+ printf("INVALID_PARTITION_LENGTH\r\n");
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * Validate the partition by calculationg the md5 checksum for the
+ * partition and compare with checksum present in checksum offset of
+ * partition
+ */
+static int zynq_validate_partition(u32 start_addr, u32 len, u32 chksum_off)
+{
+ u8 checksum[MD5_CHECKSUM_SIZE];
+ u8 calchecksum[MD5_CHECKSUM_SIZE];
+
+ memcpy(&checksum[0], (u32 *)chksum_off, MD5_CHECKSUM_SIZE);
+
+ md5_wd((u8 *)start_addr, len, &calchecksum[0], 0x10000);
+
+ if ((memcmp(checksum, calchecksum, MD5_CHECKSUM_SIZE)) != 0) {
+ printf("Error: Partition DataChecksum \r\n");
+ return -1;
+ }
+ return 0;
+}
+
+/*
+ * Extract the primary public key components from already autheticated FSBL
+ */
+static void zynq_extract_ppk(void)
+{
+ u32 padsize;
+ u8 *ppkptr;
+
+ debug("%s\n", __func__);
+
+ ppkptr = (u8 *)(fsbl_len + 0xFFFC0000);
+ padsize = ((u32)ppkptr % ZYNQ_RSA_ALIGN_PPK_START);
+ if (padsize != 0)
+ ppkptr += (ZYNQ_RSA_ALIGN_PPK_START - padsize);
+
+ ppkptr += ZYNQ_RSA_HEADER_SIZE;
+
+ ppkptr += ZYNQ_RSA_MAGIC_WORD_SIZE;
+
+ ppkmodular = (u8 *)ppkptr;
+ ppkptr += ZYNQ_RSA_MODULAR_SIZE;
+ ppkmodularex = (u8 *)ppkptr;
+ ppkptr += ZYNQ_RSA_MODULAR_EXT_SIZE;
+ ppkexp = *(u32 *)ppkptr;
+}
+
+/*
+ * Calculate the inverse(-1 / modulus[0] mod 2^32 ) for the PPK
+ */
+static u32 zynq_calc_inv(void)
+{
+ u32 modulus = public_key.modulus[0];
+ u32 tmp = BIT(1);
+ u32 inverse;
+
+ inverse = modulus & BIT(0);
+
+ while (tmp) {
+ inverse *= 2 - modulus * inverse;
+ tmp *= tmp;
+ }
+
+ return -inverse;
+}
+
+/*
+ * Recreate the signature by padding the bytes and verify with hash value
+ */
+static int zynq_pad_and_check(u8 *signature, u8 *hash)
+{
+ u8 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 */
+ if (*--pad_ptr != 0x00 || *--pad_ptr != 0x01)
+ return -1;
+
+ for (ii = 0; ii < pad; ii++) {
+ if (*--pad_ptr != 0xFF)
+ return -1;
+ }
+
+ if (*--pad_ptr != 0x00)
+ return -1;
+
+ for (ii = 0; ii < sizeof(padding); ii++) {
+ if (*--pad_ptr != padding[ii])
+ return -1;
+ }
+
+ for (ii = 0; ii < 32; ii++) {
+ if (*--pad_ptr != hash[ii])
+ return -1;
+ }
+ return 0;
+}
+
+/*
+ * Verify and extract the hash value from signature using the public key
+ * and compare it with calculated hash value.
+ */
+static int zynq_rsa_verify_key(const struct zynq_rsa_public_key *key,
+ const u8 *sig, const u32 sig_len, const u8 *hash)
+{
+ int status;
+
+ if ((!key) || (!sig) || (!hash))
+ return -1;
+
+ if (sig_len != (key->len * sizeof(u32))) {
+ printf("Signature is of incorrect length %d\n", sig_len);
+ return -1;
+ }
+
+ /* Sanity check for stack size */
+ if (sig_len > ZYNQ_RSA_SPK_SIGNATURE_SIZE) {
+ printf("Signature length %u exceeds maximum %d\n", sig_len,
+ ZYNQ_RSA_SPK_SIGNATURE_SIZE);
+ return -1;
+ }
+
+ u32 buf[sig_len / sizeof(u32)];
+
+ memcpy(buf, sig, sig_len);
+
+ status = zynq_pow_mod((u32 *)key, buf);
+ if (status == -1)
+ return status;
+
+ status = zynq_pad_and_check((u8 *)buf, (u8 *)hash);
+ if (status == -1)
+ return status;
+ return 0;
+}
+
+/*
+ * Authenticate the partition
+ */
+static int zynq_authenticate_part(u8 *buffer, u32 size)
+{
+ u8 hash_signature[32];
+ u8 *spk_modular;
+ u8 *spk_modular_ex;
+ u8 *signature_ptr;
+ u32 status;
+
+ debug("%s\n", __func__);
+
+ signature_ptr = (u8 *)(buffer + size - ZYNQ_RSA_SIGNATURE_SIZE);
+
+ signature_ptr += ZYNQ_RSA_HEADER_SIZE;
+
+ signature_ptr += ZYNQ_RSA_MAGIC_WORD_SIZE;
+
+ ppkmodular = (u8 *)signature_ptr;
+ signature_ptr += ZYNQ_RSA_MODULAR_SIZE;
+ ppkmodularex = signature_ptr;
+ signature_ptr += ZYNQ_RSA_MODULAR_EXT_SIZE;
+ signature_ptr += ZYNQ_RSA_EXPO_SIZE;
+
+ sha256_csum_wd((const unsigned char *)signature_ptr,
+ (ZYNQ_RSA_MODULAR_EXT_SIZE + ZYNQ_RSA_EXPO_SIZE +
+ ZYNQ_RSA_MODULAR_SIZE),
+ (unsigned char *)hash_signature, 0x1000);
+
+ spk_modular = (u8 *)signature_ptr;
+ signature_ptr += ZYNQ_RSA_MODULAR_SIZE;
+ spk_modular_ex = (u8 *)signature_ptr;
+ signature_ptr += ZYNQ_RSA_MODULAR_EXT_SIZE;
+ signature_ptr += ZYNQ_RSA_EXPO_SIZE;
+
+ public_key.len = ZYNQ_RSA_MODULAR_SIZE / sizeof(u32);
+ public_key.modulus = (u32 *)ppkmodular;
+ public_key.rr = (u32 *)ppkmodularex;
+ public_key.n0inv = zynq_calc_inv();
+
+ status = zynq_rsa_verify_key(&public_key, signature_ptr,
+ ZYNQ_RSA_SPK_SIGNATURE_SIZE,
+ hash_signature);
+
+ if (status)
+ return status;
+
+ signature_ptr += ZYNQ_RSA_SPK_SIGNATURE_SIZE;
+
+ sha256_csum_wd((const unsigned char *)buffer,
+ (size - ZYNQ_RSA_PARTITION_SIGNATURE_SIZE),
+ (unsigned char *)hash_signature, 0x1000);
+
+ public_key.len = ZYNQ_RSA_MODULAR_SIZE / sizeof(u32);
+ public_key.modulus = (u32 *)spk_modular;
+ public_key.rr = (u32 *)spk_modular_ex;
+ public_key.n0inv = zynq_calc_inv();
+
+ status = zynq_rsa_verify_key(&public_key, (u8 *)signature_ptr,
+ ZYNQ_RSA_PARTITION_SIGNATURE_SIZE,
+ (u8 *)hash_signature);
+
+ if (status)
+ return status;
+
+ return 0;
+}
+
+/*
+ * Parses the partition header and verfies the authenticated and
+ * encrypted image.
+ */
+static int zynq_verify_image(u32 src_ptr)
+{
+ u32 silicon_ver;
+ u32 image_base_addr;
+ u32 status;
+ u32 partition_num;
+ u32 efuseval;
+ u32 srcaddr;
+ u32 size;
+ struct partition_hdr *hdr_ptr;
+ u32 part_data_len;
+ u32 part_img_len;
+ u32 part_attr;
+ u32 part_load_addr;
+ u32 part_dst_addr;
+ u32 part_chksum_offset;
+ u32 part_start_addr;
+ u32 part_total_size;
+ u32 partitioncount;
+ u8 encrypt_part_flag;
+ u8 part_chksum_flag;
+ u8 signed_part_flag;
+
+ image_base_addr = src_ptr;
+
+ silicon_ver = zynq_get_silicon_version();
+
+ /* RSA not supported in silicon versions 1.0 and 2.0 */
+ if (silicon_ver == 0 || silicon_ver == 1)
+ return -1;
+
+ status = zynq_get_partition_info(image_base_addr);
+ if (status == -1) {
+ printf("Get Partition Info Failed\n");
+ return status;
+ }
+
+ /* Extract ppk if efuse was blown Otherwise return error */
+ efuseval = readl(&efuse_base->status);
+ if (efuseval & ZYNQ_EFUSE_RSA_ENABLE_MASK)
+ zynq_extract_ppk();
+ else
+ return -1;
+
+ partitioncount = zynq_get_part_count(&part_hdr[0]);
+
+ if ((partitioncount <= 2) ||
+ (partitioncount > ZYNQ_MAX_PARTITION_NUMBER))
+ return -1;
+
+ partition_num = 0;
+
+ while (partition_num < partitioncount) {
+ if (((part_hdr[partition_num].partitionattr &
+ ZYNQ_ATTRIBUTE_RSA_PART_OWNER_MASK) >> 16) !=
+ ZYNQ_RSA_PART_OWNER_UBOOT) {
+ printf("UBOOT is not Owner for partition %d\r\n",
+ partition_num);
+ } else {
+ hdr_ptr = &part_hdr[partition_num];
+ status = zynq_validate_hdr(hdr_ptr);
+ if (status == -1)
+ return status;
+
+ part_data_len = hdr_ptr->datawordlen;
+ part_img_len = hdr_ptr->imagewordlen;
+ part_attr = hdr_ptr->partitionattr;
+ part_load_addr = hdr_ptr->loadaddr;
+ part_chksum_offset = hdr_ptr->checksumoffset;
+ part_start_addr = hdr_ptr->partitionstart;
+ part_total_size = hdr_ptr->partitionwordlen;
+
+ if (part_data_len != part_img_len) {
+ debug("Encrypted\r\n");
+ encrypt_part_flag = 1;
+ } else {
+ encrypt_part_flag = 0;
+ }
+
+ if (part_attr & ZYNQ_ATTRIBUTE_CHECKSUM_TYPE_MASK)
+ part_chksum_flag = 1;
+ else
+ part_chksum_flag = 0;
+
+ if (part_attr & ZYNQ_ATTRIBUTE_RSA_PRESENT_MASK) {
+ debug("RSA Signed\r\n");
+ signed_part_flag = 1;
+ } else {
+ signed_part_flag = 0;
+ }
+
+ srcaddr = image_base_addr +
+ (part_start_addr << WORD_LENGTH_SHIFT);
+
+ if (part_attr & ZYNQ_ATTRIBUTE_RSA_PRESENT_MASK) {
+ signed_part_flag = 1;
+ size = part_total_size << WORD_LENGTH_SHIFT;
+ } else {
+ signed_part_flag = 0;
+ size = part_img_len;
+ }
+
+ if ((part_load_addr < gd->bd->bi_dram[0].start) &&
+ ((part_load_addr + part_data_len) >
+ (gd->bd->bi_dram[0].start +
+ gd->bd->bi_dram[0].size))) {
+ printf("INVALID_LOAD_ADDRESS_FAIL\r\n");
+ return -1;
+ }
+
+ if (part_attr & ZYNQ_ATTRIBUTE_PL_IMAGE_MASK)
+ part_load_addr = srcaddr;
+ else
+ memcpy((u32 *)part_load_addr, (u32 *)srcaddr,
+ size);
+
+ if (!signed_part_flag && !part_chksum_flag) {
+ printf("Partition not signed & no chksum\n");
+ continue;
+ }
+
+ if (part_chksum_flag) {
+ part_chksum_offset = image_base_addr +
+ (part_chksum_offset <<
+ WORD_LENGTH_SHIFT);
+ status = zynq_validate_partition(part_load_addr,
+ (part_total_size <<
+ WORD_LENGTH_SHIFT),
+ part_chksum_offset);
+ if (status != 0) {
+ printf("PART_CHKSUM_FAIL\r\n");
+ return -1;
+ }
+ debug("Partition Validation Done\r\n");
+ }
+
+ if (signed_part_flag == 1) {
+ status = zynq_authenticate_part(
+ (u8 *)part_load_addr,
+ size);
+ if (status != 0) {
+ printf("AUTHENTICATION_FAIL\r\n");
+ return -1;
+ }
+ debug("Authentication Done\r\n");
+ }
+
+ if (encrypt_part_flag) {
+ debug("DECRYPTION \r\n");
+
+ part_dst_addr = part_load_addr;
+
+ if (part_attr & ZYNQ_ATTRIBUTE_PL_IMAGE_MASK)
+ part_dst_addr = 0xFFFFFFFF;
+
+ status = zynq_decrypt_load(part_load_addr,
+ part_img_len,
+ part_dst_addr,
+ part_data_len,
+ BIT_NONE);
+ if (status != 0) {
+ printf("DECRYPTION_FAIL\r\n");
+ return -1;
+ }
+ }
+ }
+ partition_num++;
+ }
+
+ return 0;
+}
+
+static int do_zynq(cmd_tbl_t *cmdtp, int flag, int argc,
+ char * const argv[])
+{
+ u32 src_ptr;
+ int ret;
+ char *endp;
+
+ if (argc < 2 || strncmp(argv[1], "rsa", 3))
+ goto usage;
+
+ src_ptr = simple_strtoul(argv[2], &endp, 16);
+ if (*argv[2] == 0 || *endp != 0)
+ goto usage;
+
+ ret = zynq_verify_image(src_ptr);
+ if (!ret)
+ return 0;
+
+usage:
+ return CMD_RET_USAGE;
+}
+
+#ifdef CONFIG_SYS_LONGHELP
+static char zynq_help_text[] =
+ "rsa <baseaddr> - Verifies the authenticated and encrypted\n"
+ " zynq images\n";
+#endif
+
+U_BOOT_CMD(
+ zynq, 3, 0, do_zynq,
+ "Zynq specific commands RSA verfication ", zynq_help_text
+);
diff --git a/include/u-boot/rsa-mod-exp.h b/include/u-boot/rsa-mod-exp.h
index 45a031b..61068d2 100644
--- a/include/u-boot/rsa-mod-exp.h
+++ b/include/u-boot/rsa-mod-exp.h
@@ -43,6 +43,10 @@ int rsa_mod_exp_sw(const uint8_t *sig, uint32_t sig_len,
int rsa_mod_exp(struct udevice *dev, const uint8_t *sig, uint32_t sig_len,
struct key_prop *node, uint8_t *out);
+#if defined(CONFIG_CMD_ZYNQ)
+int zynq_pow_mod(u32 *keyptr, u32 *inout);
+#endif
+
/**
* struct struct mod_exp_ops - Driver model for RSA Modular Exponentiation
* operations
diff --git a/lib/rsa/rsa-mod-exp.c b/lib/rsa/rsa-mod-exp.c
index 9d78aa1..adaf433 100644
--- a/lib/rsa/rsa-mod-exp.c
+++ b/lib/rsa/rsa-mod-exp.c
@@ -301,3 +301,54 @@ int rsa_mod_exp_sw(const uint8_t *sig, uint32_t sig_len,
return 0;
}
+
+#if defined(CONFIG_CMD_ZYNQ)
+/**
+ * zynq_pow_mod() - in-place public exponentiation
+ *
+ * @keyptr: RSA key
+ * @inout: Big-endian word array containing value and result
+ *
+ * FIXME: Use pow_mod() instead of zynq_pow_mod()
+ * pow_mod calculation required for zynq is bit different from
+ * pw_mod above here, hence defined zynq specific routine.
+ */
+int zynq_pow_mod(u32 *keyptr, u32 *inout)
+{
+ u32 *result, *ptr;
+ uint i;
+ struct rsa_public_key *key;
+
+ key = (struct rsa_public_key *)keyptr;
+
+ /* Sanity check for stack size - key->len is in 32-bit words */
+ if (key->len > RSA_MAX_KEY_BITS / 32) {
+ debug("RSA key words %u exceeds maximum %d\n", key->len,
+ RSA_MAX_KEY_BITS / 32);
+ return -EINVAL;
+ }
+
+ u32 val[key->len], acc[key->len], tmp[key->len];
+
+ result = tmp; /* Re-use location. */
+
+ for (i = 0, ptr = inout; i < key->len; i++, ptr++)
+ val[i] = *(ptr);
+
+ montgomery_mul(key, acc, val, key->rr); /* axx = a * RR / R mod M */
+ for (i = 0; i < 16; i += 2) {
+ montgomery_mul(key, tmp, acc, acc); /* tmp = acc^2 / R mod M */
+ montgomery_mul(key, acc, tmp, tmp); /* acc = tmp^2 / R mod M */
+ }
+ montgomery_mul(key, result, acc, val); /* result = XX * a / R mod M */
+
+ /* Make sure result < mod; result is at most 1x mod too large. */
+ if (greater_equal_modulus(key, result))
+ subtract_modulus(key, result);
+
+ for (i = 0, ptr = inout; i < key->len; i++, ptr++)
+ *ptr = result[i];
+
+ return 0;
+}
+#endif
--
2.7.4
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