blob: 5d0785d3f1b55ed2c03e3a058440b94d3e2b5ad6 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Intel Keem Bay OCS ECC Crypto Driver.
*
* Copyright (C) 2019-2021 Intel Corporation
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/crypto.h>
#include <linux/delay.h>
#include <linux/fips.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <crypto/ecc_curve.h>
#include <crypto/ecdh.h>
#include <crypto/engine.h>
#include <crypto/kpp.h>
#include <crypto/rng.h>
#include <crypto/internal/ecc.h>
#include <crypto/internal/kpp.h>
#define DRV_NAME "keembay-ocs-ecc"
#define KMB_OCS_ECC_PRIORITY 350
#define HW_OFFS_OCS_ECC_COMMAND 0x00000000
#define HW_OFFS_OCS_ECC_STATUS 0x00000004
#define HW_OFFS_OCS_ECC_DATA_IN 0x00000080
#define HW_OFFS_OCS_ECC_CX_DATA_OUT 0x00000100
#define HW_OFFS_OCS_ECC_CY_DATA_OUT 0x00000180
#define HW_OFFS_OCS_ECC_ISR 0x00000400
#define HW_OFFS_OCS_ECC_IER 0x00000404
#define HW_OCS_ECC_ISR_INT_STATUS_DONE BIT(0)
#define HW_OCS_ECC_COMMAND_INS_BP BIT(0)
#define HW_OCS_ECC_COMMAND_START_VAL BIT(0)
#define OCS_ECC_OP_SIZE_384 BIT(8)
#define OCS_ECC_OP_SIZE_256 0
/* ECC Instruction : for ECC_COMMAND */
#define OCS_ECC_INST_WRITE_AX (0x1 << HW_OCS_ECC_COMMAND_INS_BP)
#define OCS_ECC_INST_WRITE_AY (0x2 << HW_OCS_ECC_COMMAND_INS_BP)
#define OCS_ECC_INST_WRITE_BX_D (0x3 << HW_OCS_ECC_COMMAND_INS_BP)
#define OCS_ECC_INST_WRITE_BY_L (0x4 << HW_OCS_ECC_COMMAND_INS_BP)
#define OCS_ECC_INST_WRITE_P (0x5 << HW_OCS_ECC_COMMAND_INS_BP)
#define OCS_ECC_INST_WRITE_A (0x6 << HW_OCS_ECC_COMMAND_INS_BP)
#define OCS_ECC_INST_CALC_D_IDX_A (0x8 << HW_OCS_ECC_COMMAND_INS_BP)
#define OCS_ECC_INST_CALC_A_POW_B_MODP (0xB << HW_OCS_ECC_COMMAND_INS_BP)
#define OCS_ECC_INST_CALC_A_MUL_B_MODP (0xC << HW_OCS_ECC_COMMAND_INS_BP)
#define OCS_ECC_INST_CALC_A_ADD_B_MODP (0xD << HW_OCS_ECC_COMMAND_INS_BP)
#define ECC_ENABLE_INTR 1
#define POLL_USEC 100
#define TIMEOUT_USEC 10000
#define KMB_ECC_VLI_MAX_DIGITS ECC_CURVE_NIST_P384_DIGITS
#define KMB_ECC_VLI_MAX_BYTES (KMB_ECC_VLI_MAX_DIGITS \
<< ECC_DIGITS_TO_BYTES_SHIFT)
#define POW_CUBE 3
/**
* struct ocs_ecc_dev - ECC device context
* @list: List of device contexts
* @dev: OCS ECC device
* @base_reg: IO base address of OCS ECC
* @engine: Crypto engine for the device
* @irq_done: IRQ done completion.
* @irq: IRQ number
*/
struct ocs_ecc_dev {
struct list_head list;
struct device *dev;
void __iomem *base_reg;
struct crypto_engine *engine;
struct completion irq_done;
int irq;
};
/**
* struct ocs_ecc_ctx - Transformation context.
* @engine_ctx: Crypto engine ctx.
* @ecc_dev: The ECC driver associated with this context.
* @curve: The elliptic curve used by this transformation.
* @private_key: The private key.
*/
struct ocs_ecc_ctx {
struct crypto_engine_ctx engine_ctx;
struct ocs_ecc_dev *ecc_dev;
const struct ecc_curve *curve;
u64 private_key[KMB_ECC_VLI_MAX_DIGITS];
};
/* Driver data. */
struct ocs_ecc_drv {
struct list_head dev_list;
spinlock_t lock; /* Protects dev_list. */
};
/* Global variable holding the list of OCS ECC devices (only one expected). */
static struct ocs_ecc_drv ocs_ecc = {
.dev_list = LIST_HEAD_INIT(ocs_ecc.dev_list),
.lock = __SPIN_LOCK_UNLOCKED(ocs_ecc.lock),
};
/* Get OCS ECC tfm context from kpp_request. */
static inline struct ocs_ecc_ctx *kmb_ocs_ecc_tctx(struct kpp_request *req)
{
return kpp_tfm_ctx(crypto_kpp_reqtfm(req));
}
/* Converts number of digits to number of bytes. */
static inline unsigned int digits_to_bytes(unsigned int n)
{
return n << ECC_DIGITS_TO_BYTES_SHIFT;
}
/*
* Wait for ECC idle i.e when an operation (other than write operations)
* is done.
*/
static inline int ocs_ecc_wait_idle(struct ocs_ecc_dev *dev)
{
u32 value;
return readl_poll_timeout((dev->base_reg + HW_OFFS_OCS_ECC_STATUS),
value,
!(value & HW_OCS_ECC_ISR_INT_STATUS_DONE),
POLL_USEC, TIMEOUT_USEC);
}
static void ocs_ecc_cmd_start(struct ocs_ecc_dev *ecc_dev, u32 op_size)
{
iowrite32(op_size | HW_OCS_ECC_COMMAND_START_VAL,
ecc_dev->base_reg + HW_OFFS_OCS_ECC_COMMAND);
}
/* Direct write of u32 buffer to ECC engine with associated instruction. */
static void ocs_ecc_write_cmd_and_data(struct ocs_ecc_dev *dev,
u32 op_size,
u32 inst,
const void *data_in,
size_t data_size)
{
iowrite32(op_size | inst, dev->base_reg + HW_OFFS_OCS_ECC_COMMAND);
/* MMIO Write src uint32 to dst. */
memcpy_toio(dev->base_reg + HW_OFFS_OCS_ECC_DATA_IN, data_in,
data_size);
}
/* Start OCS ECC operation and wait for its completion. */
static int ocs_ecc_trigger_op(struct ocs_ecc_dev *ecc_dev, u32 op_size,
u32 inst)
{
reinit_completion(&ecc_dev->irq_done);
iowrite32(ECC_ENABLE_INTR, ecc_dev->base_reg + HW_OFFS_OCS_ECC_IER);
iowrite32(op_size | inst, ecc_dev->base_reg + HW_OFFS_OCS_ECC_COMMAND);
return wait_for_completion_interruptible(&ecc_dev->irq_done);
}
/**
* ocs_ecc_read_cx_out() - Read the CX data output buffer.
* @dev: The OCS ECC device to read from.
* @cx_out: The buffer where to store the CX value. Must be at least
* @byte_count byte long.
* @byte_count: The amount of data to read.
*/
static inline void ocs_ecc_read_cx_out(struct ocs_ecc_dev *dev, void *cx_out,
size_t byte_count)
{
memcpy_fromio(cx_out, dev->base_reg + HW_OFFS_OCS_ECC_CX_DATA_OUT,
byte_count);
}
/**
* ocs_ecc_read_cy_out() - Read the CX data output buffer.
* @dev: The OCS ECC device to read from.
* @cy_out: The buffer where to store the CY value. Must be at least
* @byte_count byte long.
* @byte_count: The amount of data to read.
*/
static inline void ocs_ecc_read_cy_out(struct ocs_ecc_dev *dev, void *cy_out,
size_t byte_count)
{
memcpy_fromio(cy_out, dev->base_reg + HW_OFFS_OCS_ECC_CY_DATA_OUT,
byte_count);
}
static struct ocs_ecc_dev *kmb_ocs_ecc_find_dev(struct ocs_ecc_ctx *tctx)
{
if (tctx->ecc_dev)
return tctx->ecc_dev;
spin_lock(&ocs_ecc.lock);
/* Only a single OCS device available. */
tctx->ecc_dev = list_first_entry(&ocs_ecc.dev_list, struct ocs_ecc_dev,
list);
spin_unlock(&ocs_ecc.lock);
return tctx->ecc_dev;
}
/* Do point multiplication using OCS ECC HW. */
static int kmb_ecc_point_mult(struct ocs_ecc_dev *ecc_dev,
struct ecc_point *result,
const struct ecc_point *point,
u64 *scalar,
const struct ecc_curve *curve)
{
u8 sca[KMB_ECC_VLI_MAX_BYTES]; /* Use the maximum data size. */
u32 op_size = (curve->g.ndigits > ECC_CURVE_NIST_P256_DIGITS) ?
OCS_ECC_OP_SIZE_384 : OCS_ECC_OP_SIZE_256;
size_t nbytes = digits_to_bytes(curve->g.ndigits);
int rc = 0;
/* Generate random nbytes for Simple and Differential SCA protection. */
rc = crypto_get_default_rng();
if (rc)
return rc;
rc = crypto_rng_get_bytes(crypto_default_rng, sca, nbytes);
crypto_put_default_rng();
if (rc)
return rc;
/* Wait engine to be idle before starting new operation. */
rc = ocs_ecc_wait_idle(ecc_dev);
if (rc)
return rc;
/* Send ecc_start pulse as well as indicating operation size. */
ocs_ecc_cmd_start(ecc_dev, op_size);
/* Write ax param; Base point (Gx). */
ocs_ecc_write_cmd_and_data(ecc_dev, op_size, OCS_ECC_INST_WRITE_AX,
point->x, nbytes);
/* Write ay param; Base point (Gy). */
ocs_ecc_write_cmd_and_data(ecc_dev, op_size, OCS_ECC_INST_WRITE_AY,
point->y, nbytes);
/*
* Write the private key into DATA_IN reg.
*
* Since DATA_IN register is used to write different values during the
* computation private Key value is overwritten with
* side-channel-resistance value.
*/
ocs_ecc_write_cmd_and_data(ecc_dev, op_size, OCS_ECC_INST_WRITE_BX_D,
scalar, nbytes);
/* Write operand by/l. */
ocs_ecc_write_cmd_and_data(ecc_dev, op_size, OCS_ECC_INST_WRITE_BY_L,
sca, nbytes);
memzero_explicit(sca, sizeof(sca));
/* Write p = curve prime(GF modulus). */
ocs_ecc_write_cmd_and_data(ecc_dev, op_size, OCS_ECC_INST_WRITE_P,
curve->p, nbytes);
/* Write a = curve coefficient. */
ocs_ecc_write_cmd_and_data(ecc_dev, op_size, OCS_ECC_INST_WRITE_A,
curve->a, nbytes);
/* Make hardware perform the multiplication. */
rc = ocs_ecc_trigger_op(ecc_dev, op_size, OCS_ECC_INST_CALC_D_IDX_A);
if (rc)
return rc;
/* Read result. */
ocs_ecc_read_cx_out(ecc_dev, result->x, nbytes);
ocs_ecc_read_cy_out(ecc_dev, result->y, nbytes);
return 0;
}
/**
* kmb_ecc_do_scalar_op() - Perform Scalar operation using OCS ECC HW.
* @ecc_dev: The OCS ECC device to use.
* @scalar_out: Where to store the output scalar.
* @scalar_a: Input scalar operand 'a'.
* @scalar_b: Input scalar operand 'b'
* @curve: The curve on which the operation is performed.
* @ndigits: The size of the operands (in digits).
* @inst: The operation to perform (as an OCS ECC instruction).
*
* Return: 0 on success, negative error code otherwise.
*/
static int kmb_ecc_do_scalar_op(struct ocs_ecc_dev *ecc_dev, u64 *scalar_out,
const u64 *scalar_a, const u64 *scalar_b,
const struct ecc_curve *curve,
unsigned int ndigits, const u32 inst)
{
u32 op_size = (ndigits > ECC_CURVE_NIST_P256_DIGITS) ?
OCS_ECC_OP_SIZE_384 : OCS_ECC_OP_SIZE_256;
size_t nbytes = digits_to_bytes(ndigits);
int rc;
/* Wait engine to be idle before starting new operation. */
rc = ocs_ecc_wait_idle(ecc_dev);
if (rc)
return rc;
/* Send ecc_start pulse as well as indicating operation size. */
ocs_ecc_cmd_start(ecc_dev, op_size);
/* Write ax param (Base point (Gx).*/
ocs_ecc_write_cmd_and_data(ecc_dev, op_size, OCS_ECC_INST_WRITE_AX,
scalar_a, nbytes);
/* Write ay param Base point (Gy).*/
ocs_ecc_write_cmd_and_data(ecc_dev, op_size, OCS_ECC_INST_WRITE_AY,
scalar_b, nbytes);
/* Write p = curve prime(GF modulus).*/
ocs_ecc_write_cmd_and_data(ecc_dev, op_size, OCS_ECC_INST_WRITE_P,
curve->p, nbytes);
/* Give instruction A.B or A+B to ECC engine. */
rc = ocs_ecc_trigger_op(ecc_dev, op_size, inst);
if (rc)
return rc;
ocs_ecc_read_cx_out(ecc_dev, scalar_out, nbytes);
if (vli_is_zero(scalar_out, ndigits))
return -EINVAL;
return 0;
}
/* SP800-56A section 5.6.2.3.4 partial verification: ephemeral keys only */
static int kmb_ocs_ecc_is_pubkey_valid_partial(struct ocs_ecc_dev *ecc_dev,
const struct ecc_curve *curve,
struct ecc_point *pk)
{
u64 xxx[KMB_ECC_VLI_MAX_DIGITS] = { 0 };
u64 yy[KMB_ECC_VLI_MAX_DIGITS] = { 0 };
u64 w[KMB_ECC_VLI_MAX_DIGITS] = { 0 };
int rc;
if (WARN_ON(pk->ndigits != curve->g.ndigits))
return -EINVAL;
/* Check 1: Verify key is not the zero point. */
if (ecc_point_is_zero(pk))
return -EINVAL;
/* Check 2: Verify key is in the range [0, p-1]. */
if (vli_cmp(curve->p, pk->x, pk->ndigits) != 1)
return -EINVAL;
if (vli_cmp(curve->p, pk->y, pk->ndigits) != 1)
return -EINVAL;
/* Check 3: Verify that y^2 == (x^3 + a·x + b) mod p */
/* y^2 */
/* Compute y^2 -> store in yy */
rc = kmb_ecc_do_scalar_op(ecc_dev, yy, pk->y, pk->y, curve, pk->ndigits,
OCS_ECC_INST_CALC_A_MUL_B_MODP);
if (rc)
goto exit;
/* x^3 */
/* Assigning w = 3, used for calculating x^3. */
w[0] = POW_CUBE;
/* Load the next stage.*/
rc = kmb_ecc_do_scalar_op(ecc_dev, xxx, pk->x, w, curve, pk->ndigits,
OCS_ECC_INST_CALC_A_POW_B_MODP);
if (rc)
goto exit;
/* Do a*x -> store in w. */
rc = kmb_ecc_do_scalar_op(ecc_dev, w, curve->a, pk->x, curve,
pk->ndigits,
OCS_ECC_INST_CALC_A_MUL_B_MODP);
if (rc)
goto exit;
/* Do ax + b == w + b; store in w. */
rc = kmb_ecc_do_scalar_op(ecc_dev, w, w, curve->b, curve,
pk->ndigits,
OCS_ECC_INST_CALC_A_ADD_B_MODP);
if (rc)
goto exit;
/* x^3 + ax + b == x^3 + w -> store in w. */
rc = kmb_ecc_do_scalar_op(ecc_dev, w, xxx, w, curve, pk->ndigits,
OCS_ECC_INST_CALC_A_ADD_B_MODP);
if (rc)
goto exit;
/* Compare y^2 == x^3 + a·x + b. */
rc = vli_cmp(yy, w, pk->ndigits);
if (rc)
rc = -EINVAL;
exit:
memzero_explicit(xxx, sizeof(xxx));
memzero_explicit(yy, sizeof(yy));
memzero_explicit(w, sizeof(w));
return rc;
}
/* SP800-56A section 5.6.2.3.3 full verification */
static int kmb_ocs_ecc_is_pubkey_valid_full(struct ocs_ecc_dev *ecc_dev,
const struct ecc_curve *curve,
struct ecc_point *pk)
{
struct ecc_point *nQ;
int rc;
/* Checks 1 through 3 */
rc = kmb_ocs_ecc_is_pubkey_valid_partial(ecc_dev, curve, pk);
if (rc)
return rc;
/* Check 4: Verify that nQ is the zero point. */
nQ = ecc_alloc_point(pk->ndigits);
if (!nQ)
return -ENOMEM;
rc = kmb_ecc_point_mult(ecc_dev, nQ, pk, curve->n, curve);
if (rc)
goto exit;
if (!ecc_point_is_zero(nQ))
rc = -EINVAL;
exit:
ecc_free_point(nQ);
return rc;
}
static int kmb_ecc_is_key_valid(const struct ecc_curve *curve,
const u64 *private_key, size_t private_key_len)
{
size_t ndigits = curve->g.ndigits;
u64 one[KMB_ECC_VLI_MAX_DIGITS] = {1};
u64 res[KMB_ECC_VLI_MAX_DIGITS];
if (private_key_len != digits_to_bytes(ndigits))
return -EINVAL;
if (!private_key)
return -EINVAL;
/* Make sure the private key is in the range [2, n-3]. */
if (vli_cmp(one, private_key, ndigits) != -1)
return -EINVAL;
vli_sub(res, curve->n, one, ndigits);
vli_sub(res, res, one, ndigits);
if (vli_cmp(res, private_key, ndigits) != 1)
return -EINVAL;
return 0;
}
/*
* ECC private keys are generated using the method of extra random bits,
* equivalent to that described in FIPS 186-4, Appendix B.4.1.
*
* d = (c mod(n–1)) + 1 where c is a string of random bits, 64 bits longer
* than requested
* 0 <= c mod(n-1) <= n-2 and implies that
* 1 <= d <= n-1
*
* This method generates a private key uniformly distributed in the range
* [1, n-1].
*/
static int kmb_ecc_gen_privkey(const struct ecc_curve *curve, u64 *privkey)
{
size_t nbytes = digits_to_bytes(curve->g.ndigits);
u64 priv[KMB_ECC_VLI_MAX_DIGITS];
size_t nbits;
int rc;
nbits = vli_num_bits(curve->n, curve->g.ndigits);
/* Check that N is included in Table 1 of FIPS 186-4, section 6.1.1 */
if (nbits < 160 || curve->g.ndigits > ARRAY_SIZE(priv))
return -EINVAL;
/*
* FIPS 186-4 recommends that the private key should be obtained from a
* RBG with a security strength equal to or greater than the security
* strength associated with N.
*
* The maximum security strength identified by NIST SP800-57pt1r4 for
* ECC is 256 (N >= 512).
*
* This condition is met by the default RNG because it selects a favored
* DRBG with a security strength of 256.
*/
if (crypto_get_default_rng())
return -EFAULT;
rc = crypto_rng_get_bytes(crypto_default_rng, (u8 *)priv, nbytes);
crypto_put_default_rng();
if (rc)
goto cleanup;
rc = kmb_ecc_is_key_valid(curve, priv, nbytes);
if (rc)
goto cleanup;
ecc_swap_digits(priv, privkey, curve->g.ndigits);
cleanup:
memzero_explicit(&priv, sizeof(priv));
return rc;
}
static int kmb_ocs_ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
unsigned int len)
{
struct ocs_ecc_ctx *tctx = kpp_tfm_ctx(tfm);
struct ecdh params;
int rc = 0;
rc = crypto_ecdh_decode_key(buf, len, &params);
if (rc)
goto cleanup;
/* Ensure key size is not bigger then expected. */
if (params.key_size > digits_to_bytes(tctx->curve->g.ndigits)) {
rc = -EINVAL;
goto cleanup;
}
/* Auto-generate private key is not provided. */
if (!params.key || !params.key_size) {
rc = kmb_ecc_gen_privkey(tctx->curve, tctx->private_key);
goto cleanup;
}
rc = kmb_ecc_is_key_valid(tctx->curve, (const u64 *)params.key,
params.key_size);
if (rc)
goto cleanup;
ecc_swap_digits((const u64 *)params.key, tctx->private_key,
tctx->curve->g.ndigits);
cleanup:
memzero_explicit(&params, sizeof(params));
if (rc)
tctx->curve = NULL;
return rc;
}
/* Compute shared secret. */
static int kmb_ecc_do_shared_secret(struct ocs_ecc_ctx *tctx,
struct kpp_request *req)
{
struct ocs_ecc_dev *ecc_dev = tctx->ecc_dev;
const struct ecc_curve *curve = tctx->curve;
u64 shared_secret[KMB_ECC_VLI_MAX_DIGITS];
u64 pubk_buf[KMB_ECC_VLI_MAX_DIGITS * 2];
size_t copied, nbytes, pubk_len;
struct ecc_point *pk, *result;
int rc;
nbytes = digits_to_bytes(curve->g.ndigits);
/* Public key is a point, thus it has two coordinates */
pubk_len = 2 * nbytes;
/* Copy public key from SG list to pubk_buf. */
copied = sg_copy_to_buffer(req->src,
sg_nents_for_len(req->src, pubk_len),
pubk_buf, pubk_len);
if (copied != pubk_len)
return -EINVAL;
/* Allocate and initialize public key point. */
pk = ecc_alloc_point(curve->g.ndigits);
if (!pk)
return -ENOMEM;
ecc_swap_digits(pubk_buf, pk->x, curve->g.ndigits);
ecc_swap_digits(&pubk_buf[curve->g.ndigits], pk->y, curve->g.ndigits);
/*
* Check the public key for following
* Check 1: Verify key is not the zero point.
* Check 2: Verify key is in the range [1, p-1].
* Check 3: Verify that y^2 == (x^3 + a·x + b) mod p
*/
rc = kmb_ocs_ecc_is_pubkey_valid_partial(ecc_dev, curve, pk);
if (rc)
goto exit_free_pk;
/* Allocate point for storing computed shared secret. */
result = ecc_alloc_point(pk->ndigits);
if (!result) {
rc = -ENOMEM;
goto exit_free_pk;
}
/* Calculate the shared secret.*/
rc = kmb_ecc_point_mult(ecc_dev, result, pk, tctx->private_key, curve);
if (rc)
goto exit_free_result;
if (ecc_point_is_zero(result)) {
rc = -EFAULT;
goto exit_free_result;
}
/* Copy shared secret from point to buffer. */
ecc_swap_digits(result->x, shared_secret, result->ndigits);
/* Request might ask for less bytes than what we have. */
nbytes = min_t(size_t, nbytes, req->dst_len);
copied = sg_copy_from_buffer(req->dst,
sg_nents_for_len(req->dst, nbytes),
shared_secret, nbytes);
if (copied != nbytes)
rc = -EINVAL;
memzero_explicit(shared_secret, sizeof(shared_secret));
exit_free_result:
ecc_free_point(result);
exit_free_pk:
ecc_free_point(pk);
return rc;
}
/* Compute public key. */
static int kmb_ecc_do_public_key(struct ocs_ecc_ctx *tctx,
struct kpp_request *req)
{
const struct ecc_curve *curve = tctx->curve;
u64 pubk_buf[KMB_ECC_VLI_MAX_DIGITS * 2];
struct ecc_point *pk;
size_t pubk_len;
size_t copied;
int rc;
/* Public key is a point, so it has double the digits. */
pubk_len = 2 * digits_to_bytes(curve->g.ndigits);
pk = ecc_alloc_point(curve->g.ndigits);
if (!pk)
return -ENOMEM;
/* Public Key(pk) = priv * G. */
rc = kmb_ecc_point_mult(tctx->ecc_dev, pk, &curve->g, tctx->private_key,
curve);
if (rc)
goto exit;
/* SP800-56A rev 3 5.6.2.1.3 key check */
if (kmb_ocs_ecc_is_pubkey_valid_full(tctx->ecc_dev, curve, pk)) {
rc = -EAGAIN;
goto exit;
}
/* Copy public key from point to buffer. */
ecc_swap_digits(pk->x, pubk_buf, pk->ndigits);
ecc_swap_digits(pk->y, &pubk_buf[pk->ndigits], pk->ndigits);
/* Copy public key to req->dst. */
copied = sg_copy_from_buffer(req->dst,
sg_nents_for_len(req->dst, pubk_len),
pubk_buf, pubk_len);
if (copied != pubk_len)
rc = -EINVAL;
exit:
ecc_free_point(pk);
return rc;
}
static int kmb_ocs_ecc_do_one_request(struct crypto_engine *engine,
void *areq)
{
struct kpp_request *req = container_of(areq, struct kpp_request, base);
struct ocs_ecc_ctx *tctx = kmb_ocs_ecc_tctx(req);
struct ocs_ecc_dev *ecc_dev = tctx->ecc_dev;
int rc;
if (req->src)
rc = kmb_ecc_do_shared_secret(tctx, req);
else
rc = kmb_ecc_do_public_key(tctx, req);
crypto_finalize_kpp_request(ecc_dev->engine, req, rc);
return 0;
}
static int kmb_ocs_ecdh_generate_public_key(struct kpp_request *req)
{
struct ocs_ecc_ctx *tctx = kmb_ocs_ecc_tctx(req);
const struct ecc_curve *curve = tctx->curve;
/* Ensure kmb_ocs_ecdh_set_secret() has been successfully called. */
if (!tctx->curve)
return -EINVAL;
/* Ensure dst is present. */
if (!req->dst)
return -EINVAL;
/* Check the request dst is big enough to hold the public key. */
if (req->dst_len < (2 * digits_to_bytes(curve->g.ndigits)))
return -EINVAL;
/* 'src' is not supposed to be present when generate pubk is called. */
if (req->src)
return -EINVAL;
return crypto_transfer_kpp_request_to_engine(tctx->ecc_dev->engine,
req);
}
static int kmb_ocs_ecdh_compute_shared_secret(struct kpp_request *req)
{
struct ocs_ecc_ctx *tctx = kmb_ocs_ecc_tctx(req);
const struct ecc_curve *curve = tctx->curve;
/* Ensure kmb_ocs_ecdh_set_secret() has been successfully called. */
if (!tctx->curve)
return -EINVAL;
/* Ensure dst is present. */
if (!req->dst)
return -EINVAL;
/* Ensure src is present. */
if (!req->src)
return -EINVAL;
/*
* req->src is expected to the (other-side) public key, so its length
* must be 2 * coordinate size (in bytes).
*/
if (req->src_len != 2 * digits_to_bytes(curve->g.ndigits))
return -EINVAL;
return crypto_transfer_kpp_request_to_engine(tctx->ecc_dev->engine,
req);
}
static int kmb_ecc_tctx_init(struct ocs_ecc_ctx *tctx, unsigned int curve_id)
{
memset(tctx, 0, sizeof(*tctx));
tctx->ecc_dev = kmb_ocs_ecc_find_dev(tctx);
if (IS_ERR(tctx->ecc_dev)) {
pr_err("Failed to find the device : %ld\n",
PTR_ERR(tctx->ecc_dev));
return PTR_ERR(tctx->ecc_dev);
}
tctx->curve = ecc_get_curve(curve_id);
if (!tctx->curve)
return -EOPNOTSUPP;
tctx->engine_ctx.op.prepare_request = NULL;
tctx->engine_ctx.op.do_one_request = kmb_ocs_ecc_do_one_request;
tctx->engine_ctx.op.unprepare_request = NULL;
return 0;
}
static int kmb_ocs_ecdh_nist_p256_init_tfm(struct crypto_kpp *tfm)
{
struct ocs_ecc_ctx *tctx = kpp_tfm_ctx(tfm);
return kmb_ecc_tctx_init(tctx, ECC_CURVE_NIST_P256);
}
static int kmb_ocs_ecdh_nist_p384_init_tfm(struct crypto_kpp *tfm)
{
struct ocs_ecc_ctx *tctx = kpp_tfm_ctx(tfm);
return kmb_ecc_tctx_init(tctx, ECC_CURVE_NIST_P384);
}
static void kmb_ocs_ecdh_exit_tfm(struct crypto_kpp *tfm)
{
struct ocs_ecc_ctx *tctx = kpp_tfm_ctx(tfm);
memzero_explicit(tctx->private_key, sizeof(*tctx->private_key));
}
static unsigned int kmb_ocs_ecdh_max_size(struct crypto_kpp *tfm)
{
struct ocs_ecc_ctx *tctx = kpp_tfm_ctx(tfm);
/* Public key is made of two coordinates, so double the digits. */
return digits_to_bytes(tctx->curve->g.ndigits) * 2;
}
static struct kpp_alg ocs_ecdh_p256 = {
.set_secret = kmb_ocs_ecdh_set_secret,
.generate_public_key = kmb_ocs_ecdh_generate_public_key,
.compute_shared_secret = kmb_ocs_ecdh_compute_shared_secret,
.init = kmb_ocs_ecdh_nist_p256_init_tfm,
.exit = kmb_ocs_ecdh_exit_tfm,
.max_size = kmb_ocs_ecdh_max_size,
.base = {
.cra_name = "ecdh-nist-p256",
.cra_driver_name = "ecdh-nist-p256-keembay-ocs",
.cra_priority = KMB_OCS_ECC_PRIORITY,
.cra_module = THIS_MODULE,
.cra_ctxsize = sizeof(struct ocs_ecc_ctx),
},
};
static struct kpp_alg ocs_ecdh_p384 = {
.set_secret = kmb_ocs_ecdh_set_secret,
.generate_public_key = kmb_ocs_ecdh_generate_public_key,
.compute_shared_secret = kmb_ocs_ecdh_compute_shared_secret,
.init = kmb_ocs_ecdh_nist_p384_init_tfm,
.exit = kmb_ocs_ecdh_exit_tfm,
.max_size = kmb_ocs_ecdh_max_size,
.base = {
.cra_name = "ecdh-nist-p384",
.cra_driver_name = "ecdh-nist-p384-keembay-ocs",
.cra_priority = KMB_OCS_ECC_PRIORITY,
.cra_module = THIS_MODULE,
.cra_ctxsize = sizeof(struct ocs_ecc_ctx),
},
};
static irqreturn_t ocs_ecc_irq_handler(int irq, void *dev_id)
{
struct ocs_ecc_dev *ecc_dev = dev_id;
u32 status;
/*
* Read the status register and write it back to clear the
* DONE_INT_STATUS bit.
*/
status = ioread32(ecc_dev->base_reg + HW_OFFS_OCS_ECC_ISR);
iowrite32(status, ecc_dev->base_reg + HW_OFFS_OCS_ECC_ISR);
if (!(status & HW_OCS_ECC_ISR_INT_STATUS_DONE))
return IRQ_NONE;
complete(&ecc_dev->irq_done);
return IRQ_HANDLED;
}
static int kmb_ocs_ecc_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct ocs_ecc_dev *ecc_dev;
int rc;
ecc_dev = devm_kzalloc(dev, sizeof(*ecc_dev), GFP_KERNEL);
if (!ecc_dev)
return -ENOMEM;
ecc_dev->dev = dev;
platform_set_drvdata(pdev, ecc_dev);
INIT_LIST_HEAD(&ecc_dev->list);
init_completion(&ecc_dev->irq_done);
/* Get base register address. */
ecc_dev->base_reg = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(ecc_dev->base_reg)) {
dev_err(dev, "Failed to get base address\n");
rc = PTR_ERR(ecc_dev->base_reg);
goto list_del;
}
/* Get and request IRQ */
ecc_dev->irq = platform_get_irq(pdev, 0);
if (ecc_dev->irq < 0) {
rc = ecc_dev->irq;
goto list_del;
}
rc = devm_request_threaded_irq(dev, ecc_dev->irq, ocs_ecc_irq_handler,
NULL, 0, "keembay-ocs-ecc", ecc_dev);
if (rc < 0) {
dev_err(dev, "Could not request IRQ\n");
goto list_del;
}
/* Add device to the list of OCS ECC devices. */
spin_lock(&ocs_ecc.lock);
list_add_tail(&ecc_dev->list, &ocs_ecc.dev_list);
spin_unlock(&ocs_ecc.lock);
/* Initialize crypto engine. */
ecc_dev->engine = crypto_engine_alloc_init(dev, 1);
if (!ecc_dev->engine) {
dev_err(dev, "Could not allocate crypto engine\n");
rc = -ENOMEM;
goto list_del;
}
rc = crypto_engine_start(ecc_dev->engine);
if (rc) {
dev_err(dev, "Could not start crypto engine\n");
goto cleanup;
}
/* Register the KPP algo. */
rc = crypto_register_kpp(&ocs_ecdh_p256);
if (rc) {
dev_err(dev,
"Could not register OCS algorithms with Crypto API\n");
goto cleanup;
}
rc = crypto_register_kpp(&ocs_ecdh_p384);
if (rc) {
dev_err(dev,
"Could not register OCS algorithms with Crypto API\n");
goto ocs_ecdh_p384_error;
}
return 0;
ocs_ecdh_p384_error:
crypto_unregister_kpp(&ocs_ecdh_p256);
cleanup:
crypto_engine_exit(ecc_dev->engine);
list_del:
spin_lock(&ocs_ecc.lock);
list_del(&ecc_dev->list);
spin_unlock(&ocs_ecc.lock);
return rc;
}
static int kmb_ocs_ecc_remove(struct platform_device *pdev)
{
struct ocs_ecc_dev *ecc_dev;
ecc_dev = platform_get_drvdata(pdev);
if (!ecc_dev)
return -ENODEV;
crypto_unregister_kpp(&ocs_ecdh_p384);
crypto_unregister_kpp(&ocs_ecdh_p256);
spin_lock(&ocs_ecc.lock);
list_del(&ecc_dev->list);
spin_unlock(&ocs_ecc.lock);
crypto_engine_exit(ecc_dev->engine);
return 0;
}
/* Device tree driver match. */
static const struct of_device_id kmb_ocs_ecc_of_match[] = {
{
.compatible = "intel,keembay-ocs-ecc",
},
{}
};
/* The OCS driver is a platform device. */
static struct platform_driver kmb_ocs_ecc_driver = {
.probe = kmb_ocs_ecc_probe,
.remove = kmb_ocs_ecc_remove,
.driver = {
.name = DRV_NAME,
.of_match_table = kmb_ocs_ecc_of_match,
},
};
module_platform_driver(kmb_ocs_ecc_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Intel Keem Bay OCS ECC Driver");
MODULE_ALIAS_CRYPTO("ecdh-nist-p256");
MODULE_ALIAS_CRYPTO("ecdh-nist-p384");
MODULE_ALIAS_CRYPTO("ecdh-nist-p256-keembay-ocs");
MODULE_ALIAS_CRYPTO("ecdh-nist-p384-keembay-ocs");