Register ECDH and X25519 kpp algorithms using the CMH PKE core. Supports P-256, P-384, and Curve25519 for key agreement.
Signed-off-by: Alex Ousherovitch <[email protected]> Co-developed-by: Saravanakrishnan Krishnamoorthy <[email protected]> Signed-off-by: Saravanakrishnan Krishnamoorthy <[email protected]> --- drivers/crypto/cmh/Makefile | 3 +- drivers/crypto/cmh/cmh_main.c | 8 + drivers/crypto/cmh/cmh_pke_ecdh.c | 802 ++++++++++++++++++++++++++++++ 3 files changed, 812 insertions(+), 1 deletion(-) create mode 100644 drivers/crypto/cmh/cmh_pke_ecdh.c diff --git a/drivers/crypto/cmh/Makefile b/drivers/crypto/cmh/Makefile index ae1f74a93e99..da420d0ec1fe 100644 --- a/drivers/crypto/cmh/Makefile +++ b/drivers/crypto/cmh/Makefile @@ -32,7 +32,8 @@ cmh-y := \ cmh_rng.o \ cmh_pke_common.o \ cmh_pke_rsa.o \ - cmh_pke_ecdsa.o + cmh_pke_ecdsa.o \ + cmh_pke_ecdh.o # Management ioctl device (/dev/cmh_mgmt): key lifecycle, PKE, PQC ioctls. cmh-$(CONFIG_CRYPTO_DEV_CMH_MGMT) += \ diff --git a/drivers/crypto/cmh/cmh_main.c b/drivers/crypto/cmh/cmh_main.c index b5b12f56a68e..93d939e8fc4e 100644 --- a/drivers/crypto/cmh/cmh_main.c +++ b/drivers/crypto/cmh/cmh_main.c @@ -297,6 +297,11 @@ static int cmh_probe(struct platform_device *pdev) if (ret) goto err_pke_ecdsa_register; + /* Register PKE ECDH/X25519 kpp */ + ret = cmh_pke_ecdh_register(); + if (ret) + goto err_pke_ecdh_register; + /* Register key management device (/dev/cmh_mgmt) */ ret = cmh_mgmt_register(); if (ret) @@ -307,6 +312,8 @@ static int cmh_probe(struct platform_device *pdev) return 0; err_mgmt_register: + cmh_pke_ecdh_unregister(); +err_pke_ecdh_register: cmh_pke_ecdsa_unregister(); err_pke_ecdsa_register: cmh_pke_rsa_unregister(); @@ -367,6 +374,7 @@ static void cmh_remove(struct platform_device *pdev) cfg = &dev->config; cmh_mgmt_unregister(); + cmh_pke_ecdh_unregister(); cmh_pke_ecdsa_unregister(); cmh_pke_rsa_unregister(); cmh_ccp_poly_unregister(); diff --git a/drivers/crypto/cmh/cmh_pke_ecdh.c b/drivers/crypto/cmh/cmh_pke_ecdh.c new file mode 100644 index 000000000000..2264fea1facb --- /dev/null +++ b/drivers/crypto/cmh/cmh_pke_ecdh.c @@ -0,0 +1,802 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2026 Cryptography Research, Inc. (CRI). + * CMH LKM -- ECDH / X25519 kpp Driver + * + * Registers "ecdh-nist-p256", "ecdh-nist-p384", and "curve25519" + * kpp algorithms with priority 300. + * + * - set_secret: decodes private key from kpp_secret + ecdh struct + * (NIST curves) or raw 32-byte scalar (Curve25519). + * Stores in cmh_key_ctx: raw keys written via SYS_REF_TEMP. + * Datastore-referenced keys are only reachable through the ioctl + * path (cmh_mgmt.c). + * + * - generate_public_key: PKE_CMD_ECDH_KEYGEN -> outputs X coordinate + * (NIST Weierstrass) or full public key (Edwards/Montgomery). + * For NIST curves, we generate X||Y by calling ECDSA_PUBGEN instead, + * matching the kernel ecdh.c pattern that outputs uncompressed X||Y. + * + * - compute_shared_secret: PKE_CMD_ECDH -> shared secret X coordinate. + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/scatterlist.h> +#include <linux/mutex.h> +#include <crypto/kpp.h> +#include <crypto/ecdh.h> +#include <crypto/internal/kpp.h> +#include <crypto/internal/ecc.h> + +#include "cmh_pke.h" +#include "cmh_sys.h" +#include "cmh_sys_abi.h" +#include "cmh_txn.h" +#include "cmh_dma.h" +#include "cmh_key.h" + +/* + * ECDH key format: kpp_secret header + key_size(u16) + key data. + * We decode this inline to avoid depending on CONFIG_CRYPTO_ECDH. + */ +#define ECDH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + sizeof(unsigned short)) + +struct cmh_ecdh_tfm_ctx { + struct cmh_key_ctx key; + u32 curve; /* PKE_CURVE_* */ + u32 clen; /* coordinate length in bytes */ +}; + +static inline struct cmh_ecdh_tfm_ctx *cmh_ecdh_ctx(struct crypto_kpp *tfm) +{ + return kpp_tfm_ctx(tfm); +} + +/* + * Per-request context for ECDH/X25519 operations. + * + * generate_public_key and compute_shared_secret are both single-phase + * async VCQs. compute_shared_secret writes the private key into a + * per-mailbox scratch datastore object and targets SYS_REF_TEMP for the + * shared secret (see cmh_ecdh_key_scratch below). + */ +struct cmh_ecdh_reqctx { + /* Buffers */ + u8 *pk_buf; /* keygen: output public key */ + u8 *peer_buf; /* compute: peer public key */ + u8 *ss_buf; /* compute: shared secret output */ + /* DMA handles */ + dma_addr_t pk_dma; + dma_addr_t peer_dma; + dma_addr_t ss_dma; + /* Sizes and params */ + u32 out_len; /* keygen: public key size */ + u32 clen; + u32 peer_len; +}; + +/* + * Per-mailbox scratch datastore object holding the private key for + * compute_shared_secret. + * + * The CMH ECDH command writes its shared secret into a datastore object, + * not directly to host DMA. Allocating that object per request via + * SYS_CMD_NEW permanently consumes a slot every call, because the eSW + * datastore is a bump allocator with no per-object free. + * + * Instead we sys_write the private key into a persistent per-mailbox + * object (owned by that mailbox) and target SYS_REF_TEMP for the shared + * secret, which the eSW reclaims when sys_data reads it back. One object + * per mailbox preserves the round-robin PKE dispatch; the eSW runs a VCQ + * and its children to completion per mailbox, so concurrent requests on + * the same mailbox never observe each other's key in the shared object. + * + * Created on the first key set (deferred from register) and scrubbed at + * unregister, so a bring-up that never keys ECDH leaves the datastore + * empty for a DS import. Indexed by mbx_idx; entries for mailboxes + * without a PKE instance stay zero. + */ +static u64 *cmh_ecdh_key_scratch; +static u32 cmh_ecdh_scratch_count; +static bool cmh_ecdh_scratch_ready; /* DS objects created (one-shot) */ +static DEFINE_MUTEX(cmh_ecdh_scratch_lock); + +static int cmh_ecdh_scratch_ensure(void); + +/* + * cmh_ecdh_commit_key() - Ensure the key scratch exists, then stash the raw + * private key. Deferring scratch creation to the first key set keeps the + * datastore empty until ECDH is actually used. + */ +static int cmh_ecdh_commit_key(struct cmh_ecdh_tfm_ctx *ctx, + const u8 *key, u32 len) +{ + int ret = cmh_ecdh_scratch_ensure(); + + if (ret) + return ret; + return cmh_key_setkey_raw(&ctx->key, key, len, CORE_ID_PKE); +} + +/* + * set_secret: NIST curves decode kpp_secret + u16 key_size + raw scalar. + * Curve25519 uses raw 32-byte scalar directly. + */ +static int cmh_ecdh_set_secret_nist(struct crypto_kpp *tfm, + const void *buf, unsigned int len) +{ + struct cmh_ecdh_tfm_ctx *ctx = cmh_ecdh_ctx(tfm); + const u8 *ptr = buf; + struct kpp_secret secret; + unsigned short key_size; + int ret; + + if (!buf || len < ECDH_KPP_SECRET_MIN_SIZE) + return -EINVAL; + + memcpy(&secret, ptr, sizeof(secret)); + ptr += sizeof(secret); + + if (secret.type != CRYPTO_KPP_SECRET_TYPE_ECDH) + return -EINVAL; + if (len < secret.len) + return -EINVAL; + + memcpy(&key_size, ptr, sizeof(key_size)); + ptr += sizeof(key_size); + + if (key_size == 0) { + /* + * key_size == 0: generate a validated random private key. + * Uses the kernel ECC library (FIPS 186-5 A.2.2) to ensure + * the scalar is in the valid range [2, n-3] for the curve. + */ + u64 priv[ECC_MAX_DIGITS]; + unsigned int ndigits = ctx->clen / sizeof(u64); + unsigned int curve_id; + u8 *rnd; + + if (secret.len != ECDH_KPP_SECRET_MIN_SIZE) + return -EINVAL; + if (ndigits > ECC_MAX_DIGITS) + return -EINVAL; + /* Reject non-limb-aligned clen to prevent ndigits truncation */ + if (ctx->clen % sizeof(u64)) + return -EINVAL; + + if (ctx->curve == PKE_CURVE_P256) + curve_id = ECC_CURVE_NIST_P256; + else if (ctx->curve == PKE_CURVE_P384) + curve_id = ECC_CURVE_NIST_P384; + else + return -EINVAL; + + ret = ecc_gen_privkey(curve_id, ndigits, priv); + if (ret) { + memzero_explicit(priv, sizeof(priv)); + return ret; + } + + rnd = kmalloc(ctx->clen, GFP_KERNEL); + if (!rnd) { + memzero_explicit(priv, sizeof(priv)); + return -ENOMEM; + } + + /* Convert VLI (native LE-digit-order) to big-endian bytes */ + ecc_swap_digits(priv, (u64 *)rnd, ndigits); + memzero_explicit(priv, sizeof(priv)); + + ret = cmh_ecdh_commit_key(ctx, rnd, ctx->clen); + kfree_sensitive(rnd); + return ret; + } + + if (key_size != ctx->clen) + return -EINVAL; + + if (secret.len != ECDH_KPP_SECRET_MIN_SIZE + key_size) + return -EINVAL; + + /* + * Validate the raw NIST scalar is in range for the curve, matching the + * key_size==0 path (which uses ecc_gen_privkey). Rejects degenerate / + * out-of-range keys the HW might otherwise accept. + */ + { + u64 priv[ECC_MAX_DIGITS]; + unsigned int ndigits = ctx->clen / sizeof(u64); + unsigned int curve_id; + + if (ctx->clen % sizeof(u64) || ndigits > ECC_MAX_DIGITS) + return -EINVAL; + if (ctx->curve == PKE_CURVE_P256) + curve_id = ECC_CURVE_NIST_P256; + else if (ctx->curve == PKE_CURVE_P384) + curve_id = ECC_CURVE_NIST_P384; + else + return -EINVAL; + + ecc_digits_from_bytes(ptr, key_size, priv, ndigits); + ret = ecc_is_key_valid(curve_id, ndigits, priv, key_size); + memzero_explicit(priv, sizeof(priv)); + if (ret) + return ret; + } + + return cmh_ecdh_commit_key(ctx, ptr, key_size); +} + +static int cmh_ecdh_set_secret_x25519(struct crypto_kpp *tfm, + const void *buf, unsigned int len) +{ + struct cmh_ecdh_tfm_ctx *ctx = cmh_ecdh_ctx(tfm); + + if (len != pke_curve_clen(PKE_CURVE_25519)) + return -EINVAL; + + return cmh_ecdh_commit_key(ctx, buf, len); +} + +static void cmh_ecdh_keygen_complete(void *data, int error) +{ + struct kpp_request *req = data; + struct cmh_ecdh_reqctx *rctx = kpp_request_ctx(req); + + if (error == -EINPROGRESS) { + cmh_complete(&req->base, error); + return; + } + + if (!cmh_dma_map_error(rctx->pk_dma)) + cmh_dma_unmap_single(rctx->pk_dma, rctx->out_len, + DMA_FROM_DEVICE); + + if (!error) { + int nents; + + nents = sg_nents_for_len(req->dst, rctx->out_len); + if (nents < 0 || + sg_copy_from_buffer(req->dst, nents, + rctx->pk_buf, + rctx->out_len) != rctx->out_len) + error = -EINVAL; + else + req->dst_len = rctx->out_len; + } + + kfree(rctx->pk_buf); + rctx->pk_buf = NULL; + cmh_complete(&req->base, error); +} + +/* + * generate_public_key: For NIST ECDH, use ECDH_KEYGEN which outputs + * the public key X-coordinate. But the kernel kpp interface expects + * uncompressed X||Y, so we use ECDSA_PUBGEN which gives us (X,Y). + * For Curve25519, ECDH_KEYGEN gives us the Montgomery u-coordinate + * which is the full public key. + */ +static int cmh_ecdh_generate_public_key(struct kpp_request *req) +{ + struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); + struct cmh_ecdh_tfm_ctx *ctx = cmh_ecdh_ctx(tfm); + struct cmh_ecdh_reqctx *rctx = kpp_request_ctx(req); + u32 clen = ctx->clen; + bool is_25519 = (ctx->curve == PKE_CURVE_25519); + u32 out_len = is_25519 ? clen : 2 * clen; + struct vcq_cmd vcq[PKE_VCQ_CMDS_MAX]; + struct core_dispatch dd; + u32 swap, dma_swap; + int ret, idx; + gfp_t gfp; + + if (ctx->key.mode != CMH_KEY_RAW) + return -EINVAL; + if (req->dst_len < out_len) + return -EINVAL; + + gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? + GFP_KERNEL : GFP_ATOMIC; + + memset(rctx, 0, sizeof(*rctx)); + rctx->out_len = out_len; + rctx->pk_dma = DMA_MAPPING_ERROR; + + rctx->pk_buf = kzalloc(out_len, gfp); + if (!rctx->pk_buf) + return -ENOMEM; + + rctx->pk_dma = cmh_dma_map_single(rctx->pk_buf, out_len, + DMA_FROM_DEVICE); + if (cmh_dma_map_error(rctx->pk_dma)) { + ret = -ENOMEM; + goto out_free; + } + + /* + * The SYS_REF_TEMP key write uses per-curve dma_swap (0 for the + * little-endian Curve25519 secret), but the PKE compute command + * itself takes PKE_SWAP_FLAGS for every curve: the HW emits the + * public-key / shared-secret coordinate in the order PKE_SWAP_FLAGS + * maps to the expected encoding (the mgmt ECDH keygen does the same + * and matches RFC 7748). Do NOT switch the command to dma_swap. + */ + swap = PKE_SWAP_FLAGS; + dma_swap = pke_swap_flags(ctx->curve); + + dd = cmh_core_select_instance(CMH_CORE_PKE); + + vcq_set_header(&vcq[0], PKE_VCQ_CMDS_MAX); + idx = 1; + vcq_add_sys_write(&vcq[idx], SYS_REF_TEMP, ctx->key.raw.dma, + SYS_REF_NONE, ctx->key.raw.len, + ctx->key.raw.sys_type); + vcq[idx].id |= dma_swap; + idx++; + if (is_25519) + vcq_add_pke_ecdh_keygen(&vcq[idx++], dd.core_id, ctx->curve, + clen, rctx->pk_dma, SYS_REF_TEMP, + swap); + else + vcq_add_pke_ecdsa_pubgen(&vcq[idx++], dd.core_id, + ctx->curve, clen, rctx->pk_dma, + SYS_REF_TEMP, swap); + vcq_add_pke_flush(&vcq[idx++], dd.core_id); + + ret = cmh_tm_submit_async(vcq, PKE_VCQ_CMDS_MAX, 1, dd.mbx_idx, + cmh_ecdh_keygen_complete, req, + !!(req->base.flags & + CRYPTO_TFM_REQ_MAY_BACKLOG), 0); + if (ret == -EBUSY) + return -EBUSY; + if (!ret) + return -EINPROGRESS; + + if (!cmh_dma_map_error(rctx->pk_dma)) + cmh_dma_unmap_single(rctx->pk_dma, out_len, + DMA_FROM_DEVICE); + +out_free: + kfree(rctx->pk_buf); + return ret; +} + +static void cmh_ecdh_ss_complete(void *data, int error) +{ + struct kpp_request *req = data; + struct cmh_ecdh_reqctx *rctx = kpp_request_ctx(req); + + if (error == -EINPROGRESS) { + cmh_complete(&req->base, error); + return; + } + + if (!cmh_dma_map_error(rctx->peer_dma)) + cmh_dma_unmap_single(rctx->peer_dma, rctx->peer_len, + DMA_TO_DEVICE); + if (!cmh_dma_map_error(rctx->ss_dma)) + cmh_dma_unmap_single(rctx->ss_dma, rctx->clen, + DMA_FROM_DEVICE); + + if (!error) { + int nents; + + nents = sg_nents_for_len(req->dst, rctx->clen); + if (nents < 0 || + sg_copy_from_buffer(req->dst, nents, + rctx->ss_buf, + rctx->clen) != rctx->clen) + error = -EINVAL; + else + req->dst_len = rctx->clen; + } + + kfree(rctx->peer_buf); + rctx->peer_buf = NULL; + kfree_sensitive(rctx->ss_buf); + rctx->ss_buf = NULL; + cmh_complete(&req->base, error); +} + +/* + * compute_shared_secret: PKE_CMD_ECDH. + * + * req->src = peer public key (X||Y for NIST, raw 32B for Curve25519). + * Output = shared secret X coordinate (clen bytes). + * + * The CMH ECDH command stores the shared secret in a datastore object. + * We write the private key into the per-mailbox scratch object, run the + * ECDH with the shared secret targeting SYS_REF_TEMP, and read it back + * with SYS_CMD_DATA in the same VCQ -- the eSW reclaims the temp store on + * read, so no datastore slot leaks per request. + */ +static int cmh_ecdh_compute_shared_secret(struct kpp_request *req) +{ + struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); + struct cmh_ecdh_tfm_ctx *ctx = cmh_ecdh_ctx(tfm); + struct cmh_ecdh_reqctx *rctx = kpp_request_ctx(req); + u32 clen = ctx->clen; + bool is_25519 = (ctx->curve == PKE_CURVE_25519); + u32 peer_len = is_25519 ? clen : 2 * clen; + u32 ss_type = SYS_TYPE_SET(SYS_TYPE_FLAG_PT, CORE_ID_PKE); + struct vcq_cmd vcq[6]; + struct core_dispatch dd; + u64 key_ref; + u32 swap, dma_swap; + int ret, idx, nents; + gfp_t gfp; + + if (ctx->key.mode != CMH_KEY_RAW) + return -EINVAL; + if (req->src_len < peer_len || req->dst_len < clen) + return -EINVAL; + + gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? + GFP_KERNEL : GFP_ATOMIC; + + memset(rctx, 0, sizeof(*rctx)); + rctx->clen = clen; + rctx->peer_len = peer_len; + rctx->pk_dma = DMA_MAPPING_ERROR; + rctx->peer_dma = DMA_MAPPING_ERROR; + rctx->ss_dma = DMA_MAPPING_ERROR; + + rctx->peer_buf = kmalloc(peer_len, gfp); + rctx->ss_buf = kzalloc(clen, gfp); + if (!rctx->peer_buf || !rctx->ss_buf) { + ret = -ENOMEM; + goto out_free; + } + + nents = sg_nents_for_len(req->src, peer_len); + if (nents < 0 || + sg_pcopy_to_buffer(req->src, nents, rctx->peer_buf, + peer_len, 0) != peer_len) { + ret = -EINVAL; + goto out_free; + } + + rctx->peer_dma = cmh_dma_map_single(rctx->peer_buf, peer_len, + DMA_TO_DEVICE); + rctx->ss_dma = cmh_dma_map_single(rctx->ss_buf, clen, + DMA_FROM_DEVICE); + + if (cmh_dma_map_error(rctx->peer_dma) || + cmh_dma_map_error(rctx->ss_dma)) { + ret = -ENOMEM; + goto out_unmap; + } + + dd = cmh_core_select_instance(CMH_CORE_PKE); + if (dd.mbx_idx < 0 || (u32)dd.mbx_idx >= cmh_ecdh_scratch_count || + !cmh_ecdh_key_scratch[dd.mbx_idx]) { + ret = -EIO; + goto out_unmap; + } + key_ref = cmh_ecdh_key_scratch[dd.mbx_idx]; + + /* + * The private-key write uses per-curve dma_swap (0 for the + * little-endian Curve25519 secret), but the PKE compute command + * itself takes PKE_SWAP_FLAGS for every curve: the HW emits the + * shared-secret coordinate in the order PKE_SWAP_FLAGS maps to the + * expected encoding (the mgmt ECDH path does the same and matches + * RFC 7748). Do NOT switch the command to dma_swap. + */ + swap = PKE_SWAP_FLAGS; + dma_swap = pke_swap_flags(ctx->curve); + + vcq_set_header(&vcq[0], 6); + idx = 1; + vcq_add_sys_write(&vcq[idx], key_ref, ctx->key.raw.dma, + SYS_REF_NONE, ctx->key.raw.len, + ctx->key.raw.sys_type); + vcq[idx].id |= dma_swap; + idx++; + vcq_add_pke_ecdh(&vcq[idx++], dd.core_id, ctx->curve, clen, + clen, ss_type, rctx->peer_dma, + key_ref, SYS_REF_TEMP, swap); + vcq_add_pke_flush(&vcq[idx++], dd.core_id); + vcq_add_sys_data(&vcq[idx], SYS_REF_TEMP, rctx->ss_dma, clen); + vcq[idx].id |= dma_swap; + idx++; + vcq_add_sys_flush(&vcq[idx++]); + + ret = cmh_tm_submit_async(vcq, 6, 1, dd.mbx_idx, + cmh_ecdh_ss_complete, req, + !!(req->base.flags & + CRYPTO_TFM_REQ_MAY_BACKLOG), 0); + if (ret == -EBUSY) + return -EBUSY; + if (!ret) + return -EINPROGRESS; + +out_unmap: + if (!cmh_dma_map_error(rctx->ss_dma)) + cmh_dma_unmap_single(rctx->ss_dma, clen, + DMA_FROM_DEVICE); + if (!cmh_dma_map_error(rctx->peer_dma)) + cmh_dma_unmap_single(rctx->peer_dma, peer_len, + DMA_TO_DEVICE); + +out_free: + kfree_sensitive(rctx->ss_buf); + kfree(rctx->peer_buf); + return ret; +} + +static unsigned int cmh_ecdh_max_size(struct crypto_kpp *tfm) +{ + struct cmh_ecdh_tfm_ctx *ctx = cmh_ecdh_ctx(tfm); + + /* Max output = X||Y for generate_public_key (NIST) */ + return 2 * ctx->clen; +} + +static unsigned int cmh_x25519_max_size(struct crypto_kpp *tfm) +{ + return pke_curve_clen(PKE_CURVE_25519); /* single coordinate */ +} + +static int cmh_ecdh_p256_init(struct crypto_kpp *tfm) +{ + struct cmh_ecdh_tfm_ctx *ctx = cmh_ecdh_ctx(tfm); + + memset(ctx, 0, sizeof(*ctx)); + ctx->curve = PKE_CURVE_P256; + ctx->clen = pke_curve_clen(PKE_CURVE_P256); + tfm->reqsize = sizeof(struct cmh_ecdh_reqctx); + return 0; +} + +static int cmh_ecdh_p384_init(struct crypto_kpp *tfm) +{ + struct cmh_ecdh_tfm_ctx *ctx = cmh_ecdh_ctx(tfm); + + memset(ctx, 0, sizeof(*ctx)); + ctx->curve = PKE_CURVE_P384; + ctx->clen = pke_curve_clen(PKE_CURVE_P384); + tfm->reqsize = sizeof(struct cmh_ecdh_reqctx); + return 0; +} + +static int cmh_x25519_init(struct crypto_kpp *tfm) +{ + struct cmh_ecdh_tfm_ctx *ctx = cmh_ecdh_ctx(tfm); + + memset(ctx, 0, sizeof(*ctx)); + ctx->curve = PKE_CURVE_25519; + ctx->clen = pke_curve_clen(PKE_CURVE_25519); + tfm->reqsize = sizeof(struct cmh_ecdh_reqctx); + return 0; +} + +static void cmh_ecdh_exit(struct crypto_kpp *tfm) +{ + struct cmh_ecdh_tfm_ctx *ctx = cmh_ecdh_ctx(tfm); + + cmh_key_destroy(&ctx->key); +} + +static struct kpp_alg cmh_ecdh_algs[] = { + { + .set_secret = cmh_ecdh_set_secret_nist, + .generate_public_key = cmh_ecdh_generate_public_key, + .compute_shared_secret = cmh_ecdh_compute_shared_secret, + .max_size = cmh_ecdh_max_size, + .init = cmh_ecdh_p256_init, + .exit = cmh_ecdh_exit, + .base = { + .cra_name = "ecdh-nist-p256", + .cra_driver_name = "rambus-cmh-ecdh-nist-p256", + .cra_priority = 300, + .cra_flags = CRYPTO_ALG_ASYNC, + .cra_module = THIS_MODULE, + .cra_ctxsize = sizeof(struct cmh_ecdh_tfm_ctx), + }, + }, + { + .set_secret = cmh_ecdh_set_secret_nist, + .generate_public_key = cmh_ecdh_generate_public_key, + .compute_shared_secret = cmh_ecdh_compute_shared_secret, + .max_size = cmh_ecdh_max_size, + .init = cmh_ecdh_p384_init, + .exit = cmh_ecdh_exit, + .base = { + .cra_name = "ecdh-nist-p384", + .cra_driver_name = "rambus-cmh-ecdh-nist-p384", + .cra_priority = 300, + .cra_flags = CRYPTO_ALG_ASYNC, + .cra_module = THIS_MODULE, + .cra_ctxsize = sizeof(struct cmh_ecdh_tfm_ctx), + }, + }, + { + .set_secret = cmh_ecdh_set_secret_x25519, + .generate_public_key = cmh_ecdh_generate_public_key, + .compute_shared_secret = cmh_ecdh_compute_shared_secret, + .max_size = cmh_x25519_max_size, + .init = cmh_x25519_init, + .exit = cmh_ecdh_exit, + .base = { + .cra_name = "curve25519", + .cra_driver_name = "rambus-cmh-curve25519", + .cra_priority = 300, + .cra_flags = CRYPTO_ALG_ASYNC, + .cra_module = THIS_MODULE, + .cra_ctxsize = sizeof(struct cmh_ecdh_tfm_ctx), + }, + }, +}; + +/* + * cmh_ecdh_scratch_free() - Scrub and release the per-mailbox key scratch + * + * Best-effort: sys_grant with no access wipes the key bytes and clears the + * CID on each object (the datastore stack space is only reclaimed by a full + * reset). The grant runs on the owning mailbox so the eSW access check + * passes. + */ +static void cmh_ecdh_scratch_free(void) +{ + u32 i; + + if (!cmh_ecdh_key_scratch) + return; + + for (i = 0; i < cmh_ecdh_scratch_count; i++) { + struct vcq_cmd vcq[3]; + + if (!cmh_ecdh_key_scratch[i]) + continue; + + vcq_set_header(&vcq[0], 3); + vcq_add_sys_grant(&vcq[1], cmh_ecdh_key_scratch[i], 0, 0, 0); + vcq_add_sys_flush(&vcq[2]); + cmh_tm_submit_sync_mbx(vcq, 3, 1, (s32)i); + cmh_ecdh_key_scratch[i] = 0; + } + + kfree(cmh_ecdh_key_scratch); + cmh_ecdh_key_scratch = NULL; + cmh_ecdh_scratch_count = 0; + cmh_ecdh_scratch_ready = false; +} + +/* + * cmh_ecdh_scratch_ensure() - Create the per-PKE-mailbox key scratch on the + * first keyed use. + * + * Deferred from register time so that a bring-up which never sets an ECDH + * key leaves the datastore empty (a DS import requires an empty store). + * Idempotent and safe against concurrent set_secret callers; on failure it + * leaves cmh_ecdh_scratch_ready clear and any objects already created in + * place, so the next key set retries and skips them. Runs in process + * context (set_secret), so the synchronous submit may sleep. + */ +static int cmh_ecdh_scratch_ensure(void) +{ + u32 key_len = pke_curve_clen(PKE_CURVE_P384); + u32 n_pke = cmh_core_num_instances(CMH_CORE_PKE); + u64 *ref_buf; + u32 i; + int ret = 0; + + mutex_lock(&cmh_ecdh_scratch_lock); + if (cmh_ecdh_scratch_ready) + goto out; + + ref_buf = kzalloc_obj(u64, GFP_KERNEL); + if (!ref_buf) { + ret = -ENOMEM; + goto out; + } + + for (i = 0; i < n_pke; i++) { + struct core_dispatch d = cmh_core_get_instance(CMH_CORE_PKE, i); + struct vcq_cmd vcq[3]; + dma_addr_t ref_dma; + + if (d.mbx_idx < 0 || (u32)d.mbx_idx >= cmh_ecdh_scratch_count) { + ret = -EINVAL; + goto out_free; + } + if (cmh_ecdh_key_scratch[d.mbx_idx]) + continue; + + *ref_buf = 0; + ref_dma = cmh_dma_map_single(ref_buf, sizeof(*ref_buf), + DMA_FROM_DEVICE); + if (cmh_dma_map_error(ref_dma)) { + ret = -ENOMEM; + goto out_free; + } + + vcq_set_header(&vcq[0], 3); + vcq_add_sys_new(&vcq[1], 0, ref_dma, key_len); + vcq_add_sys_flush(&vcq[2]); + ret = cmh_tm_submit_sync_mbx(vcq, 3, 1, d.mbx_idx); + if (!ret) { + cmh_dma_sync_for_cpu(ref_dma, sizeof(*ref_buf), + DMA_FROM_DEVICE); + cmh_ecdh_key_scratch[d.mbx_idx] = *ref_buf; + } + cmh_dma_unmap_single(ref_dma, sizeof(*ref_buf), + DMA_FROM_DEVICE); + if (ret) + goto out_free; + if (!cmh_ecdh_key_scratch[d.mbx_idx]) { + ret = -EIO; + goto out_free; + } + } + + cmh_ecdh_scratch_ready = true; +out_free: + kfree(ref_buf); +out: + mutex_unlock(&cmh_ecdh_scratch_lock); + return ret; +} + +/** + * cmh_pke_ecdh_register() - Register ECDH kpp algorithms with the crypto framework + * + * Return: 0 on success, negative errno on failure. + */ +int cmh_pke_ecdh_register(void) +{ + u32 n_mbx = cmh_tm_mbx_count(); + int ret, i; + + if (!cmh_core_present(CMH_CORE_PKE)) + return 0; + + /* + * Host-side index array only; the per-mailbox datastore objects are + * created lazily on the first key set (cmh_ecdh_scratch_ensure) so a + * bring-up that never keys ECDH leaves the datastore empty for a DS + * import. + */ + cmh_ecdh_key_scratch = kcalloc(n_mbx, sizeof(*cmh_ecdh_key_scratch), + GFP_KERNEL); + if (!cmh_ecdh_key_scratch) + return -ENOMEM; + cmh_ecdh_scratch_count = n_mbx; + + for (i = 0; i < ARRAY_SIZE(cmh_ecdh_algs); i++) { + ret = crypto_register_kpp(&cmh_ecdh_algs[i]); + if (ret) { + dev_err(cmh_dev(), "cmh: failed to register %s (%d)\n", + cmh_ecdh_algs[i].base.cra_name, ret); + goto err_unregister; + } + } + + return 0; + +err_unregister: + while (i--) + crypto_unregister_kpp(&cmh_ecdh_algs[i]); + cmh_ecdh_scratch_free(); + return ret; +} + +/** + * cmh_pke_ecdh_unregister() - Unregister ECDH kpp algorithms from the crypto framework + */ +void cmh_pke_ecdh_unregister(void) +{ + int i = ARRAY_SIZE(cmh_ecdh_algs); + + if (!cmh_core_present(CMH_CORE_PKE)) + return; + + while (i--) + crypto_unregister_kpp(&cmh_ecdh_algs[i]); + + cmh_ecdh_scratch_free(); +} -- 2.43.7
