From patchwork Tue May 28 21:08:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 800278 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 EF040180A77; Tue, 28 May 2024 21:08:44 +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=1716930525; cv=none; b=Q/zKKMSIvucqu0m/uXcOwo48UPY0e2eW+jYeQlMXL3r8VTLjqfxFHuJSipACR4IMtqJ1z/Sse+H3CLBUIdNP+LnW9MM+d/SYXrLzlOysekV2Dc7Y1IJ/IY7YcFeveKLcEBSJa+uHMkRZtoEtD/G3uYRHjULfLbSH0VEsVrId6kI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716930525; c=relaxed/simple; bh=HjejRQyXQOkUessmoO6+Yc8j3jipeT/V6wTG5u+1Yho=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SD9NGyR7FaeXIgzTCZYeKWuf/M3PEWr+cvh/iH8aDPZZW0zVBQs1S5wPMGLet/Gxl0VUZ8H5pWwZbH7FV7kMqGoeWwcahu3yVfPEnJarY0Zb47eZgzeIGAHPCB7Ydv3mVQpHoHvvphE27B++9u+npdF6dTVdkivWz1KShPso9Aw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CBQjl9hE; 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="CBQjl9hE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27921C3277B; Tue, 28 May 2024 21:08:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716930524; bh=HjejRQyXQOkUessmoO6+Yc8j3jipeT/V6wTG5u+1Yho=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CBQjl9hEk/VLwFseULqsMirEtppqiCtEmved6duidK/Yb25r6Bn4DK4e0Z3SjUphz cqRx2ty5nO35cABBhPVrjr7KIWY5ehxIxNRfUp8DYSk/8V2khgsCRrdKREWuh97HUE vop18eB3XSJcIVQ8WpxJBQd6OP62ByNLDJl4zNlKoWBxEj2X+4YcqAFaF0U7XBSbZn 2D4cQLK0yr6eIKqpptfl01cfvqoC8VTEN2KAmjcXibbQTuILWQyTnPTIYuyY7Mbu6n fidyQXXUKUUD4hrMlLqM9lc3hmo0Gm1oTxoFi42cyaWWMWsKB1KEw+RuXBWtM31zgn KOMgZTIUc1bBg== From: Jarkko Sakkinen To: Herbert Xu Cc: linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, Andreas.Fuchs@infineon.com, James Prestwood , David Woodhouse , Eric Biggers , James Bottomley , linux-crypto@vger.kernel.org, Stefan Berger , Lennart Poettering , Jarkko Sakkinen , "David S. Miller" , linux-kernel@vger.kernel.org (open list), James Bottomley , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , linux-security-module@vger.kernel.org (open list:SECURITY SUBSYSTEM) Subject: [PATCH v7 3/5] crypto: tpm2_key: Introduce a TPM2 key type Date: Wed, 29 May 2024 00:08:08 +0300 Message-ID: <20240528210823.28798-4-jarkko@kernel.org> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240528210823.28798-1-jarkko@kernel.org> References: <20240528210823.28798-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 TPM2 ASN.1 format is required for trusted keys and asymmetric keys. Move it to crypto in order to make it available for both. Implement validation with coverage of all TPMT_PUBLIC shared fields. Key type specific fields must be covered by the different subsystems using this. A Kconfig option CRYPTO_TPM2_KEY can be used to select the feature, which depends only crypto subsystem itself and ASN.1 parser. Signed-off-by: Jarkko Sakkinen --- v6: * Relocate to crypto. Validate the shared part and provide accessor functions. Use a fixed buffer size. v2: * Do not allocate blob twice. Use the one inside struct tpm2_key. --- crypto/Kconfig | 7 ++ crypto/Makefile | 6 + crypto/tpm2_key.asn1 | 11 ++ crypto/tpm2_key.c | 134 ++++++++++++++++++++ include/crypto/tpm2_key.h | 46 +++++++ security/keys/trusted-keys/Kconfig | 2 +- security/keys/trusted-keys/Makefile | 2 - security/keys/trusted-keys/tpm2key.asn1 | 11 -- security/keys/trusted-keys/trusted_tpm2.c | 141 +++++----------------- 9 files changed, 235 insertions(+), 125 deletions(-) create mode 100644 crypto/tpm2_key.asn1 create mode 100644 crypto/tpm2_key.c create mode 100644 include/crypto/tpm2_key.h delete mode 100644 security/keys/trusted-keys/tpm2key.asn1 diff --git a/crypto/Kconfig b/crypto/Kconfig index 5688d42a59c2..c8989bc71f57 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -5,6 +5,13 @@ config XOR_BLOCKS tristate +config CRYPTO_TPM2_KEY + bool + depends on CRYPTO + select ASN1 + select OID_REGISTRY + default n + # # async_tx api: hardware offloaded memory transfer/transform support # diff --git a/crypto/Makefile b/crypto/Makefile index edbbaa3ffef5..d932fdb72319 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -216,3 +216,9 @@ obj-$(CONFIG_CRYPTO_SIMD) += crypto_simd.o # Key derivation function # obj-$(CONFIG_CRYPTO_KDF800108_CTR) += kdf_sp800108.o + +ifdef CONFIG_CRYPTO_TPM2_KEY +$(obj)/tpm2_key.asn1.o: $(obj)/tpm2_key.asn1.h $(obj)/tpm2_key.asn1.c +$(obj)/tpm2_key.o: $(obj)/tpm2_key.asn1.h +obj-y += tpm2_key.o tpm2_key.asn1.o +endif diff --git a/crypto/tpm2_key.asn1 b/crypto/tpm2_key.asn1 new file mode 100644 index 000000000000..b235d02ab78e --- /dev/null +++ b/crypto/tpm2_key.asn1 @@ -0,0 +1,11 @@ +--- +--- ASN.1 for TPM 2.0 keys +--- + +TPMKey ::= SEQUENCE { + type OBJECT IDENTIFIER ({tpm2_key_get_type}), + emptyAuth [0] EXPLICIT BOOLEAN OPTIONAL, + parent INTEGER ({tpm2_key_get_parent}), + pubkey OCTET STRING ({tpm2_get_public}), + privkey OCTET STRING ({tpm2_get_private}) + } diff --git a/crypto/tpm2_key.c b/crypto/tpm2_key.c new file mode 100644 index 000000000000..78f55478d046 --- /dev/null +++ b/crypto/tpm2_key.c @@ -0,0 +1,134 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include +#include +#include +#include +#include "tpm2_key.asn1.h" + +#undef pr_fmt +#define pr_fmt(fmt) "tpm2_key: "fmt + +struct tpm2_key_decoder_context { + u32 parent; + const u8 *pub; + u32 pub_len; + const u8 *priv; + u32 priv_len; + enum OID oid; +}; + +int tpm2_key_get_parent(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2_key_decoder_context *decoder = context; + const u8 *v = value; + int i; + + decoder->parent = 0; + for (i = 0; i < vlen; i++) { + decoder->parent <<= 8; + decoder->parent |= v[i]; + } + + return 0; +} + +int tpm2_key_get_type(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2_key_decoder_context *decoder = context; + + decoder->oid = look_up_OID(value, vlen); + return 0; +} + +static inline bool tpm2_key_is_valid(const void *value, size_t vlen) +{ + if (vlen < 2 || vlen > TPM2_KEY_BYTES_MAX) + return false; + + if (get_unaligned_be16(value) != vlen - 2) + return false; + + return true; +} + +int tpm2_get_public(void *context, size_t hdrlen, unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2_key_decoder_context *decoder = context; + + if (!tpm2_key_is_valid(value, vlen)) + return -EBADMSG; + + if (sizeof(struct tpm2_key_desc) > vlen - 2) + return -EBADMSG; + + decoder->pub = value; + decoder->pub_len = vlen; + return 0; +} + +int tpm2_get_private(void *context, size_t hdrlen, unsigned char tag, + const void *value, size_t vlen) +{ + struct tpm2_key_decoder_context *decoder = context; + + if (!tpm2_key_is_valid(value, vlen)) + return -EBADMSG; + + decoder->priv = value; + decoder->priv_len = vlen; + return 0; +} + +/** + * tpm_key_decode() - Decode TPM2 ASN.1 key + * @src: ASN.1 source. + * @src_len: ASN.1 source length. + * + * Decodes the TPM2 ASN.1 key and validates that the public key data has all + * the shared fields of TPMT_PUBLIC. This is full coverage of the memory that + * can be validated before doing any key type specific validation. + * + * Return: + * - TPM2 ASN.1 key on success. + * - -EBADMSG when decoding fails. + * - -ENOMEM when OOM while allocating struct tpm2_key. + */ +struct tpm2_key *tpm2_key_decode(const u8 *src, u32 src_len) +{ + struct tpm2_key_decoder_context decoder; + struct tpm2_key *key; + u8 *data; + int ret; + + memset(&decoder, 0, sizeof(decoder)); + ret = asn1_ber_decoder(&tpm2_key_decoder, &decoder, src, src_len); + if (ret < 0) { + if (ret != -EBADMSG) + pr_info("Decoder error %d\n", ret); + + return ERR_PTR(-EBADMSG); + } + + key = kzalloc(sizeof(*key), GFP_KERNEL); + if (!key) + return ERR_PTR(-ENOMEM); + + data = &key->data[0]; + memcpy(&data[0], decoder.priv, decoder.priv_len); + memcpy(&data[decoder.priv_len], decoder.pub, decoder.pub_len); + + key->oid = decoder.oid; + key->priv_len = decoder.priv_len; + key->pub_len = decoder.pub_len; + key->parent = decoder.parent; + key->desc = (struct tpm2_key_desc *)&data[decoder.priv_len + 2]; + return key; +} +EXPORT_SYMBOL_GPL(tpm2_key_decode); diff --git a/include/crypto/tpm2_key.h b/include/crypto/tpm2_key.h new file mode 100644 index 000000000000..74debaf707bf --- /dev/null +++ b/include/crypto/tpm2_key.h @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef __LINUX_TPM2_KEY_H__ +#define __LINUX_TPM2_KEY_H__ + +#include +#include + +#define TPM2_KEY_BYTES_MAX 1024 + +/* TPM2 Structures 12.2.4: TPMT_PUBLIC */ +struct tpm2_key_desc { + __be16 type; + __be16 name_alg; + __be32 object_attributes; + __be16 policy_size; +} __packed; + +/* Decoded TPM2 ASN.1 key. */ +struct tpm2_key { + u8 data[2 * TPM2_KEY_BYTES_MAX]; + struct tpm2_key_desc *desc; + u16 priv_len; + u16 pub_len; + u32 parent; + enum OID oid; + char oid_str[64]; +}; + +struct tpm2_key *tpm2_key_decode(const u8 *src, u32 src_len); + +static inline const void *tpm2_key_data(const struct tpm2_key *key) +{ + return &key->data[0]; +} + +static inline u16 tpm2_key_type(const struct tpm2_key *key) +{ + return be16_to_cpu(key->desc->type); +} + +static inline int tpm2_key_policy_size(const struct tpm2_key *key) +{ + return be16_to_cpu(key->desc->policy_size); +} + +#endif /* __LINUX_TPM2_KEY_H__ */ diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig index 1fb8aa001995..00d9489384ac 100644 --- a/security/keys/trusted-keys/Kconfig +++ b/security/keys/trusted-keys/Kconfig @@ -9,9 +9,9 @@ config TRUSTED_KEYS_TPM select CRYPTO_HMAC select CRYPTO_SHA1 select CRYPTO_HASH_INFO + select CRYPTO_TPM2_KEY select ASN1_ENCODER select OID_REGISTRY - select ASN1 select HAVE_TRUSTED_KEYS help Enable use of the Trusted Platform Module (TPM) as trusted key diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile index f0f3b27f688b..2674d5c10fc9 100644 --- a/security/keys/trusted-keys/Makefile +++ b/security/keys/trusted-keys/Makefile @@ -7,9 +7,7 @@ obj-$(CONFIG_TRUSTED_KEYS) += trusted.o trusted-y += trusted_core.o trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm1.o -$(obj)/trusted_tpm2.o: $(obj)/tpm2key.asn1.h trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm2.o -trusted-$(CONFIG_TRUSTED_KEYS_TPM) += tpm2key.asn1.o trusted-$(CONFIG_TRUSTED_KEYS_TEE) += trusted_tee.o diff --git a/security/keys/trusted-keys/tpm2key.asn1 b/security/keys/trusted-keys/tpm2key.asn1 deleted file mode 100644 index f57f869ad600..000000000000 --- a/security/keys/trusted-keys/tpm2key.asn1 +++ /dev/null @@ -1,11 +0,0 @@ ---- ---- ASN.1 for TPM 2.0 keys ---- - -TPMKey ::= SEQUENCE { - type OBJECT IDENTIFIER ({tpm2_key_type}), - emptyAuth [0] EXPLICIT BOOLEAN OPTIONAL, - parent INTEGER ({tpm2_key_parent}), - pubkey OCTET STRING ({tpm2_key_pub}), - privkey OCTET STRING ({tpm2_key_priv}) - } diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 06c8fa7b21ae..b9e505e99e8c 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -13,11 +13,10 @@ #include #include +#include #include -#include "tpm2key.asn1.h" - static struct tpm2_hash tpm2_hash_map[] = { {HASH_ALGO_SHA1, TPM_ALG_SHA1}, {HASH_ALGO_SHA256, TPM_ALG_SHA256}, @@ -98,106 +97,6 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, return ret; } -struct tpm2_key_context { - u32 parent; - const u8 *pub; - u32 pub_len; - const u8 *priv; - u32 priv_len; -}; - -static int tpm2_key_decode(struct trusted_key_payload *payload, - struct trusted_key_options *options, - u8 **buf) -{ - int ret; - struct tpm2_key_context ctx; - u8 *blob; - - memset(&ctx, 0, sizeof(ctx)); - - ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob, - payload->blob_len); - if (ret < 0) - return ret; - - if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE) - return -E2BIG; - - blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL); - if (!blob) - return -ENOMEM; - - *buf = blob; - options->keyhandle = ctx.parent; - - memcpy(blob, ctx.priv, ctx.priv_len); - blob += ctx.priv_len; - - memcpy(blob, ctx.pub, ctx.pub_len); - - return 0; -} - -int tpm2_key_parent(void *context, size_t hdrlen, - unsigned char tag, - const void *value, size_t vlen) -{ - struct tpm2_key_context *ctx = context; - const u8 *v = value; - int i; - - ctx->parent = 0; - for (i = 0; i < vlen; i++) { - ctx->parent <<= 8; - ctx->parent |= v[i]; - } - - return 0; -} - -int tpm2_key_type(void *context, size_t hdrlen, - unsigned char tag, - const void *value, size_t vlen) -{ - enum OID oid = look_up_OID(value, vlen); - - if (oid != OID_TPMSealedData) { - char buffer[50]; - - sprint_oid(value, vlen, buffer, sizeof(buffer)); - pr_debug("OID is \"%s\" which is not TPMSealedData\n", - buffer); - return -EINVAL; - } - - return 0; -} - -int tpm2_key_pub(void *context, size_t hdrlen, - unsigned char tag, - const void *value, size_t vlen) -{ - struct tpm2_key_context *ctx = context; - - ctx->pub = value; - ctx->pub_len = vlen; - - return 0; -} - -int tpm2_key_priv(void *context, size_t hdrlen, - unsigned char tag, - const void *value, size_t vlen) -{ - struct tpm2_key_context *ctx = context; - - ctx->priv = value; - ctx->priv_len = vlen; - - return 0; -} - /** * tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer. * @@ -387,22 +286,43 @@ static int tpm2_load_cmd(struct tpm_chip *chip, struct trusted_key_options *options, u32 *blob_handle) { - struct tpm_buf buf; unsigned int private_len; unsigned int public_len; unsigned int blob_len; - u8 *blob, *pub; - int rc; + struct tpm2_key *key; + const u8 *blob, *pub; + struct tpm_buf buf; u32 attrs; + int rc; - rc = tpm2_key_decode(payload, options, &blob); - if (rc) { - /* old form */ + key = tpm2_key_decode(payload->blob, payload->blob_len); + if (IS_ERR(key)) { + /* Get the error code and reset the pointer to the key: */ + rc = PTR_ERR(key); + key = NULL; + + if (rc == -ENOMEM) + return -ENOMEM; + + /* A sanity check, as only -EBADMSG or -ENOMEM are expected: */ + if (rc != -EBADMSG) + pr_err("tpm2_key_decode(): spurious error code %d\n", rc); + + /* Fallback to the legacy format: */ blob = payload->blob; payload->old_format = 1; + } else { + blob = tpm2_key_data(key); + if (key->oid != OID_TPMSealedData) { + kfree(key); + return -EBADMSG; + } } - /* new format carries keyhandle but old format doesn't */ + /* + * Must be non-zero here, either extracted from the ASN.1 for the new + * format or specified on the command line for the old. + */ if (!options->keyhandle) return -EINVAL; @@ -464,8 +384,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip, (__be32 *) &buf.data[TPM_HEADER_SIZE]); out: - if (blob != payload->blob) - kfree(blob); + kfree(key); tpm_buf_destroy(&buf); if (rc > 0)