From 007c3ff11f38d83cc95b0f402e432cbf484e3c31 Mon Sep 17 00:00:00 2001 From: Ahmad Fatoum Date: Fri, 13 May 2022 16:57:02 +0200 Subject: [PATCH] crypto: caam - add in-kernel interface for blob generator The NXP Cryptographic Acceleration and Assurance Module (CAAM) can be used to protect user-defined data across system reboot: - When the system is fused and boots into secure state, the master key is a unique never-disclosed device-specific key - random key is encrypted by key derived from master key - data is encrypted using the random key - encrypted data and its encrypted random key are stored alongside - This blob can now be safely stored in non-volatile memory On next power-on: - blob is loaded into CAAM - CAAM writes decrypted data either into memory or key register Add functions to realize encrypting and decrypting into memory alongside the CAAM driver. They will be used in a later commit as a source for the trusted key seal/unseal mechanism. Reviewed-by: David Gstir Reviewed-by: Pankaj Gupta Tested-by: Tim Harvey Tested-by: Matthias Schiffer Tested-by: Pankaj Gupta Tested-by: Michael Walle # on ls1028a (non-E and E) Tested-by: John Ernberg # iMX8QXP Signed-off-by: Steffen Trumtrar Signed-off-by: Ahmad Fatoum Signed-off-by: Jarkko Sakkinen --- drivers/crypto/caam/Kconfig | 3 + drivers/crypto/caam/Makefile | 1 + drivers/crypto/caam/blob_gen.c | 182 +++++++++++++++++++++++++++++++++ include/soc/fsl/caam-blob.h | 103 +++++++++++++++++++ 4 files changed, 289 insertions(+) create mode 100644 drivers/crypto/caam/blob_gen.c create mode 100644 include/soc/fsl/caam-blob.h diff --git a/drivers/crypto/caam/Kconfig b/drivers/crypto/caam/Kconfig index 84ea7cba5ee5..ea9f8b1ae981 100644 --- a/drivers/crypto/caam/Kconfig +++ b/drivers/crypto/caam/Kconfig @@ -151,6 +151,9 @@ config CRYPTO_DEV_FSL_CAAM_RNG_API Selecting this will register the SEC4 hardware rng to the hw_random API for supplying the kernel entropy pool. +config CRYPTO_DEV_FSL_CAAM_BLOB_GEN + bool + endif # CRYPTO_DEV_FSL_CAAM_JR endif # CRYPTO_DEV_FSL_CAAM diff --git a/drivers/crypto/caam/Makefile b/drivers/crypto/caam/Makefile index 3570286eb9ce..25f7ae5a4642 100644 --- a/drivers/crypto/caam/Makefile +++ b/drivers/crypto/caam/Makefile @@ -21,6 +21,7 @@ caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API_QI) += caamalg_qi.o caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_AHASH_API) += caamhash.o caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_API) += caamrng.o caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_PKC_API) += caampkc.o pkc_desc.o +caam_jr-$(CONFIG_CRYPTO_DEV_FSL_CAAM_BLOB_GEN) += blob_gen.o caam-$(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API_QI) += qi.o ifneq ($(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API_QI),) diff --git a/drivers/crypto/caam/blob_gen.c b/drivers/crypto/caam/blob_gen.c new file mode 100644 index 000000000000..6345c7269eb0 --- /dev/null +++ b/drivers/crypto/caam/blob_gen.c @@ -0,0 +1,182 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2015 Pengutronix, Steffen Trumtrar + * Copyright (C) 2021 Pengutronix, Ahmad Fatoum + */ + +#define pr_fmt(fmt) "caam blob_gen: " fmt + +#include +#include + +#include "compat.h" +#include "desc_constr.h" +#include "desc.h" +#include "error.h" +#include "intern.h" +#include "jr.h" +#include "regs.h" + +#define CAAM_BLOB_DESC_BYTES_MAX \ + /* Command to initialize & stating length of descriptor */ \ + (CAAM_CMD_SZ + \ + /* Command to append the key-modifier + key-modifier data */ \ + CAAM_CMD_SZ + CAAM_BLOB_KEYMOD_LENGTH + \ + /* Command to include input key + pointer to the input key */ \ + CAAM_CMD_SZ + CAAM_PTR_SZ_MAX + \ + /* Command to include output key + pointer to the output key */ \ + CAAM_CMD_SZ + CAAM_PTR_SZ_MAX + \ + /* Command describing the operation to perform */ \ + CAAM_CMD_SZ) + +struct caam_blob_priv { + struct device jrdev; +}; + +struct caam_blob_job_result { + int err; + struct completion completion; +}; + +static void caam_blob_job_done(struct device *dev, u32 *desc, u32 err, void *context) +{ + struct caam_blob_job_result *res = context; + int ecode = 0; + + dev_dbg(dev, "%s %d: err 0x%x\n", __func__, __LINE__, err); + + if (err) + ecode = caam_jr_strstatus(dev, err); + + res->err = ecode; + + /* + * Upon completion, desc points to a buffer containing a CAAM job + * descriptor which encapsulates data into an externally-storable + * blob. + */ + complete(&res->completion); +} + +int caam_process_blob(struct caam_blob_priv *priv, + struct caam_blob_info *info, bool encap) +{ + struct caam_blob_job_result testres; + struct device *jrdev = &priv->jrdev; + dma_addr_t dma_in, dma_out; + int op = OP_PCLID_BLOB; + size_t output_len; + u32 *desc; + int ret; + + if (info->key_mod_len > CAAM_BLOB_KEYMOD_LENGTH) + return -EINVAL; + + if (encap) { + op |= OP_TYPE_ENCAP_PROTOCOL; + output_len = info->input_len + CAAM_BLOB_OVERHEAD; + } else { + op |= OP_TYPE_DECAP_PROTOCOL; + output_len = info->input_len - CAAM_BLOB_OVERHEAD; + } + + desc = kzalloc(CAAM_BLOB_DESC_BYTES_MAX, GFP_KERNEL | GFP_DMA); + if (!desc) + return -ENOMEM; + + dma_in = dma_map_single(jrdev, info->input, info->input_len, + DMA_TO_DEVICE); + if (dma_mapping_error(jrdev, dma_in)) { + dev_err(jrdev, "unable to map input DMA buffer\n"); + ret = -ENOMEM; + goto out_free; + } + + dma_out = dma_map_single(jrdev, info->output, output_len, + DMA_FROM_DEVICE); + if (dma_mapping_error(jrdev, dma_out)) { + dev_err(jrdev, "unable to map output DMA buffer\n"); + ret = -ENOMEM; + goto out_unmap_in; + } + + /* + * A data blob is encrypted using a blob key (BK); a random number. + * The BK is used as an AES-CCM key. The initial block (B0) and the + * initial counter (Ctr0) are generated automatically and stored in + * Class 1 Context DWords 0+1+2+3. The random BK is stored in the + * Class 1 Key Register. Operation Mode is set to AES-CCM. + */ + + init_job_desc(desc, 0); + append_key_as_imm(desc, info->key_mod, info->key_mod_len, + info->key_mod_len, CLASS_2 | KEY_DEST_CLASS_REG); + append_seq_in_ptr_intlen(desc, dma_in, info->input_len, 0); + append_seq_out_ptr_intlen(desc, dma_out, output_len, 0); + append_operation(desc, op); + + print_hex_dump_debug("data@"__stringify(__LINE__)": ", + DUMP_PREFIX_ADDRESS, 16, 1, info->input, + info->input_len, false); + print_hex_dump_debug("jobdesc@"__stringify(__LINE__)": ", + DUMP_PREFIX_ADDRESS, 16, 1, desc, + desc_bytes(desc), false); + + testres.err = 0; + init_completion(&testres.completion); + + ret = caam_jr_enqueue(jrdev, desc, caam_blob_job_done, &testres); + if (ret == -EINPROGRESS) { + wait_for_completion(&testres.completion); + ret = testres.err; + print_hex_dump_debug("output@"__stringify(__LINE__)": ", + DUMP_PREFIX_ADDRESS, 16, 1, info->output, + output_len, false); + } + + if (ret == 0) + info->output_len = output_len; + + dma_unmap_single(jrdev, dma_out, output_len, DMA_FROM_DEVICE); +out_unmap_in: + dma_unmap_single(jrdev, dma_in, info->input_len, DMA_TO_DEVICE); +out_free: + kfree(desc); + + return ret; +} +EXPORT_SYMBOL(caam_process_blob); + +struct caam_blob_priv *caam_blob_gen_init(void) +{ + struct caam_drv_private *ctrlpriv; + struct device *jrdev; + + /* + * caam_blob_gen_init() may expectedly fail with -ENODEV, e.g. when + * CAAM driver didn't probe or when SoC lacks BLOB support. An + * error would be harsh in this case, so we stick to info level. + */ + + jrdev = caam_jr_alloc(); + if (IS_ERR(jrdev)) { + pr_info("job ring requested, but none currently available\n"); + return ERR_PTR(-ENODEV); + } + + ctrlpriv = dev_get_drvdata(jrdev->parent); + if (!ctrlpriv->blob_present) { + dev_info(jrdev, "no hardware blob generation support\n"); + caam_jr_free(jrdev); + return ERR_PTR(-ENODEV); + } + + return container_of(jrdev, struct caam_blob_priv, jrdev); +} +EXPORT_SYMBOL(caam_blob_gen_init); + +void caam_blob_gen_exit(struct caam_blob_priv *priv) +{ + caam_jr_free(&priv->jrdev); +} +EXPORT_SYMBOL(caam_blob_gen_exit); diff --git a/include/soc/fsl/caam-blob.h b/include/soc/fsl/caam-blob.h new file mode 100644 index 000000000000..937cac52f36d --- /dev/null +++ b/include/soc/fsl/caam-blob.h @@ -0,0 +1,103 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2020 Pengutronix, Ahmad Fatoum + */ + +#ifndef __CAAM_BLOB_GEN +#define __CAAM_BLOB_GEN + +#include +#include + +#define CAAM_BLOB_KEYMOD_LENGTH 16 +#define CAAM_BLOB_OVERHEAD (32 + 16) +#define CAAM_BLOB_MAX_LEN 4096 + +struct caam_blob_priv; + +/** + * struct caam_blob_info - information for CAAM blobbing + * @input: pointer to input buffer (must be DMAable) + * @input_len: length of @input buffer in bytes. + * @output: pointer to output buffer (must be DMAable) + * @output_len: length of @output buffer in bytes. + * @key_mod: key modifier + * @key_mod_len: length of @key_mod in bytes. + * May not exceed %CAAM_BLOB_KEYMOD_LENGTH + */ +struct caam_blob_info { + void *input; + size_t input_len; + + void *output; + size_t output_len; + + const void *key_mod; + size_t key_mod_len; +}; + +/** + * caam_blob_gen_init - initialize blob generation + * Return: pointer to new &struct caam_blob_priv instance on success + * and ``ERR_PTR(-ENODEV)`` if CAAM has no hardware blobbing support + * or no job ring could be allocated. + */ +struct caam_blob_priv *caam_blob_gen_init(void); + +/** + * caam_blob_gen_exit - free blob generation resources + * @priv: instance returned by caam_blob_gen_init() + */ +void caam_blob_gen_exit(struct caam_blob_priv *priv); + +/** + * caam_process_blob - encapsulate or decapsulate blob + * @priv: instance returned by caam_blob_gen_init() + * @info: pointer to blobbing info describing key, blob and + * key modifier buffers. + * @encap: true for encapsulation, false for decapsulation + * + * Return: %0 and sets ``info->output_len`` on success and a negative + * error code otherwise. + */ +int caam_process_blob(struct caam_blob_priv *priv, + struct caam_blob_info *info, bool encap); + +/** + * caam_encap_blob - encapsulate blob + * @priv: instance returned by caam_blob_gen_init() + * @info: pointer to blobbing info describing input key, + * output blob and key modifier buffers. + * + * Return: %0 and sets ``info->output_len`` on success and + * a negative error code otherwise. + */ +static inline int caam_encap_blob(struct caam_blob_priv *priv, + struct caam_blob_info *info) +{ + if (info->output_len < info->input_len + CAAM_BLOB_OVERHEAD) + return -EINVAL; + + return caam_process_blob(priv, info, true); +} + +/** + * caam_decap_blob - decapsulate blob + * @priv: instance returned by caam_blob_gen_init() + * @info: pointer to blobbing info describing output key, + * input blob and key modifier buffers. + * + * Return: %0 and sets ``info->output_len`` on success and + * a negative error code otherwise. + */ +static inline int caam_decap_blob(struct caam_blob_priv *priv, + struct caam_blob_info *info) +{ + if (info->input_len < CAAM_BLOB_OVERHEAD || + info->output_len < info->input_len - CAAM_BLOB_OVERHEAD) + return -EINVAL; + + return caam_process_blob(priv, info, false); +} + +#endif