From patchwork Sat May 18 21:36:25 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 13667715 X-Patchwork-Delegate: herbert@gondor.apana.org.au Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C19606CDA3; Sat, 18 May 2024 21:37:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716068266; cv=none; b=LwJCdOlNDWAljq8X8txpcKouK7DPOFsZyzEvTniotGxm4S/hFeh3DOm10nBrMYf9WrnQoYRvMUjpROkTTg9Yy2UgHf7KUKX/OpX/b/aQOdfbcyOqpGe4awZV19I+HeWoldgf/Ufs6y/jg2vJPP9kYoGiXweAxRxUxlDzPkI0eFE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716068266; c=relaxed/simple; bh=R2SZeE+P5GdD5yWwmn4/xrJZ3ND6iUZHLjBTx0bcb6g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZycYMy3OsVwy1BNXoh6i3BPu+pmOjWho1eS+3MDZp/6sDL9m0kiXkxciehZ8OupSmHiXXKWfsN5aoAsysewiVnwtO3jCuDaIEafwKzL9BSBXGS5tyqs86ZBn3Xe5/YMndmMCjfbBGRtWi2kSYw1UuBaHMCXaquIiCsD9ghl5hHc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OtIFinNO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OtIFinNO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D42AC113CC; Sat, 18 May 2024 21:37:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716068266; bh=R2SZeE+P5GdD5yWwmn4/xrJZ3ND6iUZHLjBTx0bcb6g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OtIFinNOX0kCH+VULG9GRBPKgigsAsbX8OhqUdD6kFj+HtAxWi7c1Fg43+LpZuY7h BZJNyzgUweifFVBmXtcUsRPUfSFix7dDa5EkmIJ0/jD4+44m8PAwkYc66HYK1Laecr 2r52U2OEFnmwJapxTqUVVj5Im6gFOqGXaLg0BQc+EOinOUIspQHgz2Ff22dx+7vFNu StsmUIlj2ksuR+FY3csvZtD9abCQV1YB/BJvtBrhh2OaAg5OJkLq0p+emwgiZ5GW5W jHbfIftJEh/Xk1WpWxpoUJijMMXroj/JkCNrRgkZ++WpXvgnCCsFV2TZB+m2R2yrAB WKuTnpIkmLokA== From: Jarkko Sakkinen To: Herbert Xu Cc: linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, Andreas.Fuchs@infineon.com, James Prestwood , David Woodhouse , Jarkko Sakkinen , David Howells , "David S. Miller" , Peter Huewe , Jason Gunthorpe , James Bottomley , Stefan Berger , Ard Biesheuvel , Mario Limonciello , linux-crypto@vger.kernel.org (open list:CRYPTO API), linux-kernel@vger.kernel.org (open list) Subject: [PATCH RFC 5/5] keys: asymmetric: ASYMMETRIC_TPM2_KEY_RSA_SUBTYPE Date: Sun, 19 May 2024 00:36:25 +0300 Message-ID: <20240518213700.5960-6-jarkko@kernel.org> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240518213700.5960-1-jarkko@kernel.org> References: <20240518213700.5960-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: James Prestwood Based on earlier work by James Prestwood. Add ASN.1 compatible asymmetric TPM2 RSA key subtype: 1. Signing and decryption (with the private key) is handled by TPM2_RSA_Decrypt. 2. Encryption (with the public key) is handled by the kernel RSA implementation. Link: https://lore.kernel.org/all/20200518172704.29608-1-prestwoj@gmail.com/ Signed-off-by: James Prestwood Co-developed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- crypto/asymmetric_keys/Kconfig | 12 + crypto/asymmetric_keys/Makefile | 1 + crypto/asymmetric_keys/tpm2_key_rsa.c | 648 ++++++++++++++++++++++++++ drivers/char/tpm/tpm2_key.c | 11 + include/crypto/tpm2_key.h | 3 + include/linux/tpm.h | 1 + 6 files changed, 676 insertions(+) create mode 100644 crypto/asymmetric_keys/tpm2_key_rsa.c diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig index e1345b8f39f1..0ccbc0e80aa2 100644 --- a/crypto/asymmetric_keys/Kconfig +++ b/crypto/asymmetric_keys/Kconfig @@ -23,6 +23,18 @@ config ASYMMETRIC_PUBLIC_KEY_SUBTYPE appropriate hash algorithms (such as SHA-1) must be available. ENOPKG will be reported if the requisite algorithm is unavailable. +config ASYMMETRIC_TPM2_KEY_RSA_SUBTYPE + tristate "Asymmetric TPM2 RSA crypto algorithm subtype" + depends on TCG_TPM && TCG_TPM2_HAMC + select CRYPTO_RSA + select CRYPTO_SHA256 + select CRYPTO_HASH_INFO + help + This option provides support for asymmetric TPM2 key type handling. + If signature generation and/or verification are to be used, + appropriate hash algorithms (such as SHA-256) must be available. + ENOPKG will be reported if the requisite algorithm is unavailable. + config X509_CERTIFICATE_PARSER tristate "X.509 certificate parser" depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile index bc65d3b98dcb..f9730b39f008 100644 --- a/crypto/asymmetric_keys/Makefile +++ b/crypto/asymmetric_keys/Makefile @@ -11,6 +11,7 @@ asymmetric_keys-y := \ signature.o obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += public_key.o +obj-$(CONFIG_ASYMMETRIC_TPM2_KEY_SUBTYPE) += tpm2_key_rsa.o # # X.509 Certificate handling diff --git a/crypto/asymmetric_keys/tpm2_key_rsa.c b/crypto/asymmetric_keys/tpm2_key_rsa.c new file mode 100644 index 000000000000..8f245dd1b8b0 --- /dev/null +++ b/crypto/asymmetric_keys/tpm2_key_rsa.c @@ -0,0 +1,648 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* TPM2 asymmetric public-key crypto subtype + * + * See Documentation/crypto/asymmetric-keys.rst + * + * Copyright (c) 2020 Intel Corporation + */ + +#define pr_fmt(fmt) "tpm2_key: "fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* Room to fit two u32 zeros for algo id and parameters length. */ +#define SETKEY_PARAMS_SIZE (sizeof(u32) * 2) + +/* + * Maximum buffer size for the BER/DER encoded public key. The public key + * is of the form SEQUENCE { INTEGER n, INTEGER e } where n is a maximum 2048 + * bit key and e is usually 65537 + * The encoding overhead is: + * - max 4 bytes for SEQUENCE + * - max 4 bytes for INTEGER n type/length + * - 257 bytes of n + * - max 2 bytes for INTEGER e type/length + * - 3 bytes of e + * - 4+4 of zeros for set_pub_key parameters (SETKEY_PARAMS_SIZE) + */ +#define PUB_KEY_BUF_SIZE (4 + 4 + 257 + 2 + 3 + SETKEY_PARAMS_SIZE) + +static int tpm2_rsa_decrypt(struct tpm_chip *chip, u32 parent, + const unsigned char *keyblob, size_t bloblen, + const void *data, size_t len, void *out) +{ + unsigned int private_len; + unsigned int public_len; + unsigned int parsed_len; + unsigned int offset = 0; + u32 blob_handle = 0; + u32 key_handle = 0; + struct tpm_buf buf; + u16 decrypted_len; + u8 *pos; + int ret; + + private_len = be16_to_cpup((__be16 *)&keyblob[0]); + if (private_len > (bloblen - 2)) + return -EINVAL; + + public_len = be16_to_cpup((__be16 *)&keyblob[2 + private_len]); + parsed_len = private_len + public_len + 4; + if (parsed_len > bloblen) + return -EINVAL; + + chip = tpm_find_get_ops(chip); + if (!chip) + return -ENODEV; + + ret = tpm2_start_auth_session(chip); + if (ret) + goto err_ops; + + if (parent == TPM2_RH_NULL) { + ret = tpm2_load_context(chip, chip->null_key_context, &offset, + &key_handle); + if (ret) { + ret = -EIO; + goto err_auth; + } + } else { + key_handle = parent; + } + + ret = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD); + if (ret < 0) + goto err_key; + + tpm_buf_append_name(chip, &buf, key_handle, NULL); + tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_CONTINUE_SESSION | + TPM2_SA_ENCRYPT, NULL, 0); + tpm_buf_append(&buf, keyblob, bloblen); + + if (buf.flags & TPM_BUF_OVERFLOW) { + ret = -E2BIG; + goto err_buf; + } + + tpm_buf_fill_hmac_session(chip, &buf); + ret = tpm_transmit_cmd(chip, &buf, 4, "loading blob"); + ret = tpm_buf_check_hmac_response(chip, &buf, ret); + if (ret) { + ret = -EIO; + goto err_buf; + } + + blob_handle = be32_to_cpup((__be32 *)&buf.data[TPM_HEADER_SIZE]); + + tpm_buf_reset(&buf, TPM2_ST_SESSIONS, TPM2_CC_RSA_DECRYPT); + + tpm_buf_append_name(chip, &buf, blob_handle, NULL); + tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT, NULL, 0); + + tpm_buf_append_u16(&buf, len); + tpm_buf_append(&buf, data, len); + tpm_buf_append_u16(&buf, TPM_ALG_NULL); + tpm_buf_append_u16(&buf, 0); + + tpm_buf_fill_hmac_session(chip, &buf); + ret = tpm_transmit_cmd(chip, &buf, 4, "decrypting RSA"); + ret = tpm_buf_check_hmac_response(chip, &buf, ret); + if (ret) { + ret = -EIO; + goto err_blob; + } + + pos = buf.data + TPM_HEADER_SIZE + 4; + decrypted_len = be16_to_cpup((__be16 *)pos); + pos += 2; + + memcpy(out, pos, decrypted_len); + ret = decrypted_len; + +err_blob: + tpm2_flush_context(chip, blob_handle); + +err_buf: + tpm_buf_destroy(&buf); + +err_key: + tpm2_flush_context(chip, key_handle); + +err_auth: + if (ret < 0) + tpm2_end_auth_session(chip); + +err_ops: + tpm_put_ops(chip); + return ret; +} + +/* + * PKCS1 padding (type 1) + */ +static int __maybe_unused tpm2_pad_pkcs1(const u8 *m, unsigned int mlen, + u8 *em, unsigned int em_len) +{ + unsigned int ps_len = em_len - mlen - 3; + + if (mlen > em_len - 11) + return -EBADMSG; + + em[0] = 0; + em[1] = 1; + + memset(em + 2, 0xff, ps_len); + + em[2 + ps_len] = 0; + memcpy(em + 2 + ps_len + 1, m, mlen); + + return 0; +} + +/* + * RFC 3447 - Section 7.2.2 + */ +static const u8 *tpm2_unpad_pkcs1(const u8 *data, unsigned int len, + unsigned int *out_len) +{ + unsigned int i; + + /* + * Size of input data should be checked against public key size by + * caller. + */ + if (data[0] != 0 || data[1] != 2) + return NULL; + + i = 2; + + while (data[i] != 0 && i < len) + i++; + + if (i == len) + return NULL; + + *out_len = len - i - 1; + + return data + i + 1; +} + +/* + * Outputs the cipher algorithm name on success, and retuns -ENOPKG + * on failure. + */ +static int tpm2_key_get_akcipher(const char *encoding, const char *hash_algo, + char *cipher) +{ + ssize_t ret; + + if (strcmp(encoding, "pkcs1") == 0) { + if (!hash_algo) { + strscpy(cipher, "pkcs1pad(rsa)"); + return 0; + } + + ret = snprintf(cipher, CRYPTO_MAX_ALG_NAME, + "pkcs1pad(rsa,%s)", + hash_algo); + if (ret >= CRYPTO_MAX_ALG_NAME) + return -ENOPKG; + + return 0; + } + + if (strcmp(encoding, "raw") == 0) { + strscpy(cipher, "rsa"); + return 0; + } + + return -ENOPKG; +} + +static inline u8 *tpm2_key_append_tag(u8 *buf, u8 tag, u32 len) +{ + *buf++ = tag; + + if (len <= 127) { + buf[0] = len; + return buf + 1; + } + + if (len <= 255) { + buf[0] = 0x81; + buf[1] = len; + return buf + 2; + } + + buf[0] = 0x82; + put_unaligned_be16(len, buf + 1); + return buf + 3; +} + +static inline u32 tpm2_key_definite_length(u32 len) +{ + if (len <= 127) + return 1; + if (len <= 255) + return 2; + return 3; +} + +static u32 tpm2_key_to_der(const void *pub_key, u32 len, u8 *buf) +{ + u8 *cur = buf; + u32 n_len = tpm2_key_definite_length(len) + 1 + len + 1; + u32 e_len = tpm2_key_definite_length(3) + 1 + 3; + u8 e[3] = { 0x01, 0x00, 0x01 }; + + /* SEQUENCE */ + cur = tpm2_key_append_tag(cur, 0x30, n_len + e_len); + /* INTEGER n */ + cur = tpm2_key_append_tag(cur, 0x02, len + 1); + cur[0] = 0x00; + memcpy(cur + 1, pub_key, len); + cur += len + 1; + cur = tpm2_key_append_tag(cur, 0x02, sizeof(e)); + memcpy(cur, e, sizeof(e)); + cur += sizeof(e); + /* Zero parameters to satisfy set_pub_key ABI. */ + memset(cur, 0, SETKEY_PARAMS_SIZE); + + return cur - buf; +} + +/* + * Encryption operation is performed with the public key. Hence it is done + * in software + */ +static int tpm2_key_rsa_encrypt(struct tpm2_key *key, + struct kernel_pkey_params *params, + const void *in, void *out) +{ + char cipher[CRYPTO_MAX_ALG_NAME]; + struct scatterlist in_sg, out_sg; + u8 der_pub_key[PUB_KEY_BUF_SIZE]; + struct akcipher_request *req; + struct crypto_akcipher *tfm; + struct crypto_wait cwait; + u32 der_pub_key_len; + int rc; + + rc = tpm2_key_get_akcipher(params->encoding, params->hash_algo, cipher); + if (rc < 0) + return rc; + + tfm = crypto_alloc_akcipher(cipher, 0, 0); + if (IS_ERR(tfm)) + return PTR_ERR(tfm); + + der_pub_key_len = tpm2_key_to_der(key->pub, key->pub_len, der_pub_key); + + rc = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len); + if (rc < 0) + goto err_tfm; + + req = akcipher_request_alloc(tfm, GFP_KERNEL); + if (!req) { + rc = -ENOMEM; + goto err_tfm; + } + + sg_init_one(&in_sg, in, params->in_len); + sg_init_one(&out_sg, out, params->out_len); + akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len, + params->out_len); + + crypto_init_wait(&cwait); + akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | + CRYPTO_TFM_REQ_MAY_SLEEP, + crypto_req_done, &cwait); + + rc = crypto_akcipher_encrypt(req); + rc = crypto_wait_req(rc, &cwait); + + if (!rc) + rc = req->dst_len; + + akcipher_request_free(req); + +err_tfm: + crypto_free_akcipher(tfm); + + return rc; +} + +/* + * Decryption operation is performed with the private key in the TPM. + */ +static int tpm2_key_rsa_decrypt(struct tpm_chip *chip, struct tpm2_key *key, + size_t in_len, const void *in, void *out) +{ + unsigned int unpadded_len; + const u8 *unpadded; + u8 *decrypted; + int rc; + + decrypted = kmalloc(key->pub_len, GFP_KERNEL); + + rc = tpm2_rsa_decrypt(chip, key->parent, key->blob, key->blob_len, in, + in_len, decrypted); + if (rc < 0) + return rc; + + unpadded = tpm2_unpad_pkcs1(decrypted, rc, &unpadded_len); + if (!unpadded) + return -EINVAL; + + memcpy(out, unpadded, unpadded_len); + return unpadded_len; +} + +/* + * Sign operation is an encryption using the TPM's private key. With RSA the + * only difference between encryption and decryption is where the padding goes. + * Since own padding can be used, TPM2_RSA_Decrypt can be repurposed to do + * encryption. + */ +static int tpm2_key_rsa_sign(struct tpm_chip *chip, struct tpm2_key *key, + struct kernel_pkey_params *params, + const void *in, void *out) +{ + const struct rsa_asn1_template *asn1; + u32 in_len = params->in_len; + void *asn1_wrapped = NULL; + u8 *padded; + int rc; + + if (strcmp(params->encoding, "pkcs1")) { + rc = -ENOPKG; + goto done; + } + + if (params->hash_algo) { + asn1 = rsa_lookup_asn1(params->hash_algo); + if (!asn1) { + rc = -ENOPKG; + goto done; + } + + /* Request enough space for the ASN.1 template + input hash */ + asn1_wrapped = kzalloc(in_len + asn1->size, GFP_KERNEL); + if (!asn1_wrapped) { + rc = -ENOMEM; + goto done; + } + + /* Copy ASN.1 template, then the input */ + memcpy(asn1_wrapped, asn1->data, asn1->size); + memcpy(asn1_wrapped + asn1->size, in, in_len); + + in = asn1_wrapped; + in_len += asn1->size; + } + + /* + * Using the TPM's decrypt call to sign (aka encrypt). This + * requires pre-padding the data with PKCS1. + */ + padded = kmalloc(key->pub_len, GFP_KERNEL); + tpm2_pad_pkcs1(in, in_len, padded, key->pub_len); + + rc = tpm2_rsa_decrypt(chip, key->parent, key->blob, key->blob_len, + padded, key->pub_len, out); + + kfree(padded); +done: + kfree(asn1_wrapped); + return rc; +} + +static void tpm2_key_rsa_describe(const struct key *asymmetric_key, + struct seq_file *m) +{ + struct tpm2_key *key = asymmetric_key->payload.data[asym_crypto]; + + if (!key) { + pr_err("key is empty"); + return; + } + + seq_puts(m, "TPM2/RSA"); +} + +static void tpm2_key_rsa_destroy(void *payload0, void *payload3) +{ + struct tpm2_key *key = payload0; + + if (!key) + return; + + tpm2_key_destroy(key); +} + +static int tpm2_key_rsa_eds_op(struct kernel_pkey_params *params, + const void *in, void *out) +{ + struct tpm2_key *tk = params->key->payload.data[asym_crypto]; + struct tpm_chip *chip = tpm_default_chip(); + int rc = -EOPNOTSUPP; + + if (!chip) + return -ENODEV; + + switch (params->op) { + case kernel_pkey_encrypt: + rc = tpm2_key_encrypt(tk, params, in, out); + break; + case kernel_pkey_decrypt: + rc = tpm2_key_decrypt(tk, chip, params, in, out); + break; + case kernel_pkey_sign: + rc = tpm2_key_sign(tk, chip, params, in, out); + break; + default: + return -EINVAL; + } + + return rc; +} + +static int tpm2_key_rsa_verify(const struct key *key, + const struct public_key_signature *sig) +{ + const struct tpm2_key *tk = key->payload.data[asym_crypto]; + char alg_name[CRYPTO_MAX_ALG_NAME]; + u8 der_pub_key[PUB_KEY_BUF_SIZE]; + struct akcipher_request *req; + struct scatterlist src_sg[2]; + struct crypto_akcipher *tfm; + struct crypto_wait cwait; + u32 der_pub_key_len; + int rc; + + if (WARN_ON(!tk || !sig || !sig->s)) + return -EINVAL; + + if (!sig->digest) + return -ENOPKG; + + rc = determine_akcipher(sig->encoding, sig->hash_algo, alg_name); + if (rc < 0) + return rc; + + tfm = crypto_alloc_akcipher(alg_name, 0, 0); + if (IS_ERR(tfm)) + return PTR_ERR(tfm); + + der_pub_key_len = derive_pub_key(tk->pub, tk->pub_len, + der_pub_key); + + rc = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len); + if (rc < 0) + goto err_tfm; + + rc = -ENOMEM; + req = akcipher_request_alloc(tfm, GFP_KERNEL); + if (!req) + goto err_tfm; + + sg_init_table(src_sg, 2); + sg_set_buf(&src_sg[0], sig->s, sig->s_size); + sg_set_buf(&src_sg[1], sig->digest, sig->digest_size); + akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size, + sig->digest_size); + crypto_init_wait(&cwait); + akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | + CRYPTO_TFM_REQ_MAY_SLEEP, + crypto_req_done, &cwait); + rc = crypto_wait_req(crypto_akcipher_verify(req), &cwait); + + akcipher_request_free(req); +err_tfm: + crypto_free_akcipher(tfm); + pr_devel("<=%s() = %d\n", __func__, rc); + if (WARN_ON_ONCE(rc > 0)) + rc = -EINVAL; + return rc; +} + +static int tpm2_key_query(const struct kernel_pkey_params *params, + struct kernel_pkey_query *info) +{ + struct tpm2_key *tk = params->key->payload.data[asym_crypto]; + char alg_name[CRYPTO_MAX_ALG_NAME]; + u8 der_pub_key[PUB_KEY_BUF_SIZE]; + struct crypto_akcipher *tfm; + u32 der_pub_key_len = 0; + unsigned int len; + int ret; + + ret = determine_akcipher(params->encoding, params->hash_algo, alg_name); + if (ret < 0) + return ret; + + tfm = crypto_alloc_akcipher(alg_name, 0, 0); + if (IS_ERR(tfm)) + return PTR_ERR(tfm); + + der_pub_key_len = derive_pub_key(tk->pub, tk->pub_len, + der_pub_key); + + ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len); + if (ret < 0) + goto err_tfm; + + len = crypto_akcipher_maxsize(tfm); + + info->key_size = tk->pub_len * 8; + info->max_data_size = tk->pub_len; + info->max_sig_size = len; + info->max_enc_size = len; + info->max_dec_size = tk->pub_len; + + info->supported_ops = KEYCTL_SUPPORTS_ENCRYPT | + KEYCTL_SUPPORTS_DECRYPT | + KEYCTL_SUPPORTS_VERIFY | + KEYCTL_SUPPORTS_SIGN; + +err_tfm: + crypto_free_akcipher(tfm); + return ret; +} + +/* + * Asymmetric TPM2 RSA key. Signs and decrypts with TPM. + */ +struct asymmetric_key_subtype tpm2_key_rsa_subtype = { + .owner = THIS_MODULE, + .name = "tpm2_key_rsa", + .name_len = sizeof("tpm2_key_rsa") - 1, + .describe = tpm2_key_rsa_describe, + .destroy = tpm2_key_rsa_destroy, + .query = tpm2_key_rsa_query, + .eds_op = tpm2_key_rsa_eds_op, + .verify_signature = tpm2_key_rsa_verify, +}; +EXPORT_SYMBOL_GPL(tpm2_key_rsa_subtype); + +/* + * Attempt to parse a data blob for a key as a TPM private key blob. + */ +static int tpm2_key_preparse(struct key_preparsed_payload *prep) +{ + struct tpm2_key key; + int ret; + + memset(&key, 0, sizeof(key)); + + /* + * TPM 2.0 RSA keys are recommended to be 2048 bits long. Assume the + * blob is no more than 4x that. + */ + if (prep->datalen > 256 * 4) + return -EMSGSIZE; + + ret = tpm2_key_decode(prep->data, prep->data_len, &key, MAX_BLOB_SIZE); + if (ret) + return ret; + + prep->payload.data[asym_subtype] = &tpm2_key_rsa_subtype; + prep->payload.data[asym_key_ids] = NULL; + prep->payload.data[asym_crypto] = tk; + prep->payload.data[asym_auth] = NULL; + prep->quotalen = 100; + + return 0; +} + +static struct asymmetric_key_parser tpm2_key_rsa_parser = { + .owner = THIS_MODULE, + .name = "tpm2_key_rsa_parser", + .parse = tpm2_key_preparse, +}; + +static int __init tpm2_key_rsa_init(void) +{ + return register_asymmetric_key_parser(&tpm2_key_parser); +} + +static void __exit tpm2_key_rsa_exit(void) +{ + unregister_asymmetric_key_parser(&tpm2_key_parser); +} + +module_init(tpm2_key_rsa_init); +module_exit(tpm2_key_rsa_exit); + +MODULE_DESCRIPTION("Asymmetric TPM2 RSA key"); +MODULE_LICENSE("GPL"); diff --git a/drivers/char/tpm/tpm2_key.c b/drivers/char/tpm/tpm2_key.c index e09441efb0f0..0d125b53de0e 100644 --- a/drivers/char/tpm/tpm2_key.c +++ b/drivers/char/tpm/tpm2_key.c @@ -175,6 +175,17 @@ int tpm2_key_decode(const u8 *src, u32 src_len, struct tpm2_key *key, return -ENOMEM; } + ctx.blob_len = ctx.priv_len + ctx.pub_len; + ctx.blob = kmalloc(ctx.priv_len + ctx.pub_len, GFP_KERNEL); + if (!ctx.blob) { + kfree(ctx.pub); + kfree(ctx.priv); + return -ENOMEM; + } + + memcpy((void *)ctx.blob, ctx.priv, ctx.priv_len); + memcpy((void *)ctx.blob + ctx.priv_len, ctx.pub, ctx.pub_len); + memcpy(key, &ctx, sizeof(ctx)); return 0; } diff --git a/include/crypto/tpm2_key.h b/include/crypto/tpm2_key.h index e5d3330afef5..7b5c5ec6bed5 100644 --- a/include/crypto/tpm2_key.h +++ b/include/crypto/tpm2_key.h @@ -13,6 +13,8 @@ struct tpm2_key { u32 pub_len; const u8 *priv; u32 priv_len; + const u8 *blob; + u32 blob_len; }; int tpm2_key_encode(u8 *blob, u32 blob_auth_len, u32 key_handle, u8 *src); @@ -27,6 +29,7 @@ static inline void tpm2_key_destroy(struct tpm2_key *key) { kfree(key->priv); kfree(key->pub); + kfree(key->blob); memset(key, 0, sizeof(*key)); } diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 2f25ca07127b..238814ee5c6f 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -271,6 +271,7 @@ enum tpm2_command_codes { TPM2_CC_NV_READ = 0x014E, TPM2_CC_CREATE = 0x0153, TPM2_CC_LOAD = 0x0157, + TPM2_CC_RSA_DECRYPT = 0x0159, TPM2_CC_SEQUENCE_UPDATE = 0x015C, TPM2_CC_UNSEAL = 0x015E, TPM2_CC_CONTEXT_LOAD = 0x0161,