| Message ID | 20240521031645.17008-7-jarkko@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KEYS: asymmetric: tpm2_key_rsa | expand |
> -----Original Message----- > From: Jarkko Sakkinen <jarkko@kernel.org> > Sent: Tuesday, May 21, 2024 8:47 AM > To: Herbert Xu <herbert@gondor.apana.org.au> > Cc: linux-integrity@vger.kernel.org; keyrings@vger.kernel.org; > Andreas.Fuchs@infineon.com; James Prestwood <prestwoj@gmail.com>; > David Woodhouse <dwmw2@infradead.org>; Eric Biggers > <ebiggers@kernel.org>; James Bottomley > <James.Bottomley@hansenpartnership.com>; Jarkko Sakkinen > <jarkko@kernel.org>; David S. Miller <davem@davemloft.net>; open > list:CRYPTO API <linux-crypto@vger.kernel.org>; open list <linux- > kernel@vger.kernel.org>; David Howells <dhowells@redhat.com>; James > Bottomley <James.Bottomley@HansenPartnership.com>; Stefan Berger > <stefanb@linux.ibm.com>; Ard Biesheuvel <ardb@kernel.org>; Mario > Limonciello <mario.limonciello@amd.com> > Subject: [EXTERNAL] [PATCH v2 6/6] keys: asymmetric: > ASYMMETRIC_TPM2_KEY_RSA_SUBTYPE > > ---------------------------------------------------------------------- > From: James Prestwood <prestwoj@gmail.com> > > 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://urldefense.proofpoint.com/v2/url?u=https- > 3A__lore.kernel.org_all_20200518172704.29608-2D1-2Dprestwoj- > 40gmail.com_&d=DwIDAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=PAAlWswPe7d8 > gHlGbCLmy2YezyK7O3Hv_t2heGnouBw&m=OMixrhGWcekpXpja15IeSeghOU > 4mBNCZOSB2Vgtzbn7xcodoWU_Hnnpzp_eZh- > XR&s=pKVMCPyvi19wJur3Bzq2xo3MtPHsEicDLBGr--NWRjs&e= > Signed-off-by: James Prestwood <prestwoj@gmail.com> > Co-developed-by: Jarkko Sakkinen <jarkko@kernel.org> > Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> > --- > v2: > * Remove two spurios pr_info() messsages that I forgot to remove. > * Clean up padding functions and add additional checks for length > also in tpm2_unpad_pcks1(). > * Add the missing success check kzalloc() in tpm2_key_rsa_decrypt(). > * Check that params->out_len for capacity before copying the result. > --- > crypto/asymmetric_keys/Kconfig | 16 + > crypto/asymmetric_keys/Makefile | 1 + > crypto/asymmetric_keys/tpm2_key_rsa.c | 698 > ++++++++++++++++++++++++++ > include/linux/tpm.h | 2 + > 4 files changed, 717 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..4d14bb0c346e 100644 > --- a/crypto/asymmetric_keys/Kconfig > +++ b/crypto/asymmetric_keys/Kconfig > @@ -15,6 +15,7 @@ config ASYMMETRIC_PUBLIC_KEY_SUBTYPE > select MPILIB > select CRYPTO_HASH_INFO > select CRYPTO_AKCIPHER > + select CRYPTO_RSA > select CRYPTO_SIG > select CRYPTO_HASH > help > @@ -23,6 +24,21 @@ 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 > + select TCG_TPM2_HMAC > + select CRYPTO_RSA > + select CRYPTO_SHA256 > + select CRYPTO_HASH_INFO > + select ASN1 > + select ASN1_ENCODER > + 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..c6da84607824 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_RSA_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..32250ff38268 > --- /dev/null > +++ b/crypto/asymmetric_keys/tpm2_key_rsa.c > @@ -0,0 +1,698 @@ > +// 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 > + */ > + > +#include <asm/unaligned.h> > +#include <crypto/akcipher.h> > +#include <crypto/public_key.h> > +#include <crypto/rsa-pkcs1pad.h> > +#include <crypto/tpm2_key.h> > +#include <keys/asymmetric-parser.h> > +#include <keys/asymmetric-subtype.h> > +#include <keys/trusted-type.h> > +#include <linux/asn1_encoder.h> > +#include <linux/keyctl.h> > +#include <linux/module.h> > +#include <linux/scatterlist.h> > +#include <linux/slab.h> > +#include <linux/tpm.h> > + > +#undef pr_fmt > +#define pr_fmt(fmt) "tpm2_key_rsa: "fmt > + > +#define PUB_KEY_BUF_SIZE 512 > + > +struct tpm2_key_rsa { > + struct tpm2_key key; > + const u8 *pub; > + int pub_len; > +}; > + > +static const int PKCS1_PAD_MIN_SIZE = 11; > + > +/* > + * Fill the data with PKCS#1 v1.5 padding. > + */ > +static int tpm2_pad_pkcs1(const u8 *in, int in_len, u8 *out, int out_len) > +{ > + unsigned int prefix_len = out_len - in_len - 3; > + > + if (in_len > out_len - PKCS1_PAD_MIN_SIZE) > + return -EBADMSG; > + > + /* prefix */ > + out[0] = 0; > + out[1] = 1; > + memset(&out[2], 0xff, prefix_len); > + out[2 + prefix_len] = 0; > + /* payload */ > + memcpy(&out[2 + prefix_len + 1], in, in_len); > + > + return 0; > +} > + > +/* > + * RFC 3447 - Section 7.2.2 > + * Size of the input data should be checked against public key size by > + * the caller. > + */ > +static const u8 *tpm2_unpad_pkcs1(const u8 *in, int in_len, int *out_len) > +{ > + int i; > + > + if (in[0] != 0 || in[1] != 2) > + return NULL; > + > + i = 2; > + while (in[i] != 0 && i < in_len) > + i++; > + > + if (i == in_len || i < (PKCS1_PAD_MIN_SIZE - 1)) > + return NULL; > + > + *out_len = in_len - i - 1; > + return in + 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) { > + strcpy(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) { > + strcpy(cipher, "rsa"); > + return 0; > + } > + > + return -ENOPKG; > +} > + > +static int tpm2_key_rsa_extract_pub(struct tpm2_key_rsa *key_rsa) > +{ > + struct tpm2_key *key = &key_rsa->key; > + struct tpm_buf buf; > + off_t offset = 2; > + u16 policy_len; > + u32 attr; > + u16 bits; > + u16 type; > + u16 len; > + u16 alg; > + u32 exp; > + > + buf.flags = TPM_BUF_TPM2B; > + buf.length = key->pub_len; > + buf.data = (void *)key->pub; > + > + if (get_unaligned_be16(key->pub) != buf.length - 2) > + return -EINVAL; > + > + type = tpm_buf_read_u16(&buf, &offset); > + pr_debug("pub type: 0x%04x\n", type); > + if (type != TPM_ALG_RSA) > + return -EINVAL; > + > + alg = tpm_buf_read_u16(&buf, &offset); > + pr_debug("pub name alg: 0x%04x\n", alg); > + attr = tpm_buf_read_u32(&buf, &offset); > + pr_debug("pub attributes: 0x%08x\n", attr); > + policy_len = tpm_buf_read_u16(&buf, &offset); > + pr_debug("pub policy length: %u bytes\n", policy_len); > + offset += policy_len; > + > + alg = tpm_buf_read_u16(&buf, &offset); > + pr_debug("pub symmetric: 0x%04x\n", alg); > + if (alg != TPM_ALG_NULL) > + return -EINVAL; > + > + alg = tpm_buf_read_u16(&buf, &offset); > + pr_debug("pub symmetric scheme: 0x%04x\n", alg); > + if (alg != TPM_ALG_NULL) > + return -EINVAL; > + > + bits = tpm_buf_read_u16(&buf, &offset); > + pr_debug("pub bits: %u\n", bits); > + > + exp = tpm_buf_read_u32(&buf, &offset); > + pr_debug("pub exponent: 0x%08x\n", exp); > + if (exp != 0x00000000 && exp != 0x00010001) > + return -EINVAL; > + > + len = tpm_buf_read_u16(&buf, &offset); > + pr_debug("pub modulus: %u bytes\n", len); > + key_rsa->pub = key->pub + offset; > + key_rsa->pub_len = len; > + > + return buf.flags & TPM_BUF_BOUNDARY_ERROR ? -EIO : 0; > +} > + > +static int tpm2_key_rsa_encode(const struct tpm2_key_rsa *key, u8 *buf) > +{ > + const int SCRATCH_SIZE = PAGE_SIZE; > + const u8 exp[3] = {1, 0, 1}; > + u8 *scratch, *work, *work1, *end_work; > + int pub_len = key->pub_len; > + const u8 *pub = key->pub; > + int ret; > + > + scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL); > + if (!scratch) > + return -ENOMEM; > + > + work = scratch; > + end_work = &scratch[SCRATCH_SIZE]; > + > + work = asn1_encode_integer(work, end_work, pub, pub_len); > + if (IS_ERR(work)) { > + ret = PTR_ERR(work); > + goto err; > + } > + > + work = asn1_encode_integer(work, end_work, exp, 3); > + if (IS_ERR(work)) { > + ret = PTR_ERR(work); > + goto err; > + } > + > + work1 = buf; > + work1 = asn1_encode_sequence(work1, > &work1[PUB_KEY_BUF_SIZE], > + scratch, work - scratch); > + if (IS_ERR(work1)) { > + ret = PTR_ERR(work1); > + goto err; > + } > + > + memset(work1, 0, 8); > + > + kfree(scratch); > + return work1 - buf; > + > +err: > + kfree(scratch); > + return ret; > +} > + > +/* > + * Encryption operation is performed with the public key. Hence it is done > + * in software > + */ > +static int tpm2_key_rsa_encrypt(struct tpm2_key_rsa *key, > + struct kernel_pkey_params *params, > + const void *in, void *out) > +{ > + char cipher[CRYPTO_MAX_ALG_NAME]; > + struct scatterlist in_sg, out_sg; > + u8 enc_pub_key[PUB_KEY_BUF_SIZE]; > + struct akcipher_request *req; > + struct crypto_akcipher *tfm; > + struct crypto_wait cwait; > + 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); > + > + rc = tpm2_key_rsa_encode(key, enc_pub_key); > + if (rc < 0) > + goto err_tfm; > + > + rc = crypto_akcipher_set_pub_key(tfm, enc_pub_key, rc); > + 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); > + Few Minor comments, Extra line here > + if (!rc) > + rc = req->dst_len; > + > + akcipher_request_free(req); > + > +err_tfm: > + crypto_free_akcipher(tfm); > + > + return rc; > +} > + > +static int __tpm2_key_rsa_decrypt(struct tpm_chip *chip, > + struct tpm2_key_rsa *key, > + struct kernel_pkey_params *params, > + const void *in, int in_len, void *out) > +{ > + unsigned int offset = 0; > + u32 key_handle = 0; > + struct tpm_buf buf; > + u16 decrypted_len; > + u32 parent; > + u8 *pos; > + int ret; > + > + ret = tpm_try_get_ops(chip); > + if (ret) > + return ret; > + > + ret = tpm2_start_auth_session(chip); > + if (ret) > + goto err_ops; > + > + if (key->key.parent == TPM2_RH_NULL) { > + ret = tpm2_load_context(chip, chip->null_key_context, > &offset, > + &parent); > + if (ret) { > + ret = -EIO; > + goto err_auth; > + } > + } else { > + parent = key->key.parent; > + } Do we need braces here? > + > + ret = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD); > + if (ret < 0) > + goto err_parent; > + > + tpm_buf_append_name(chip, &buf, parent, NULL); > + tpm_buf_append_hmac_session(chip, &buf, > TPM2_SA_CONTINUE_SESSION | > + TPM2_SA_ENCRYPT, NULL, 0); > + tpm_buf_append(&buf, key->key.blob, key->key.blob_len); > + 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, "RSA key loading"); > + ret = tpm_buf_check_hmac_response(chip, &buf, ret); > + if (ret) { > + ret = -EIO; > + goto err_buf; > + } > + key_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, key_handle, NULL); > + tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT, > NULL, 0); > + tpm_buf_append_u16(&buf, in_len); > + tpm_buf_append(&buf, in, in_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, "RSA key decrypting"); > + 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; > + > + if (params->out_len < decrypted_len) { > + ret = -EMSGSIZE; > + goto err_blob; > + } > + > + memcpy(out, pos, decrypted_len); > + ret = decrypted_len; > + > +err_blob: > + tpm2_flush_context(chip, key_handle); > + > +err_buf: > + tpm_buf_destroy(&buf); > + > +err_parent: > + if (key->key.parent == TPM2_RH_NULL) > + tpm2_flush_context(chip, parent); > + > +err_auth: > + if (ret < 0) > + tpm2_end_auth_session(chip); > + > +err_ops: > + tpm_put_ops(chip); > + return ret; > +} > + > +static int tpm2_key_rsa_decrypt(struct tpm_chip *chip, struct tpm2_key_rsa > *key, > + struct kernel_pkey_params *params, > + const void *in, void *out) > +{ > + const u8 *ptr; > + int out_len; > + u8 *work; > + int ret; > + > + work = kzalloc(params->out_len, GFP_KERNEL); > + if (!work) > + return -ENOMEM; Maybe use ERR_PTR() here and couple of more places > + > + ret = __tpm2_key_rsa_decrypt(chip, key, params, in, params->in_len, > + work); > + if (ret < 0) > + goto err; > + > + ptr = tpm2_unpad_pkcs1(work, ret, &out_len); > + if (!ptr) { > + ret = -EINVAL; > + goto err; > + } > + > + if (out_len > params->out_len) { > + ret = -EMSGSIZE; > + goto err; > + } > + > + memcpy(out, ptr, out_len); > + kfree(work); > + return out_len; > + > +err: > + kfree(work); > + return ret; > +} > + > +/* > + * 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_rsa > *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; > + int pub_len = key->pub_len; > + u8 *padded; > + int ret; > + > + if (strcmp(params->encoding, "pkcs1") != 0) { > + ret = -ENOPKG; > + goto err; > + } > + > + if (params->hash_algo) { > + asn1 = rsa_lookup_asn1(params->hash_algo); > + if (!asn1) { > + ret = -ENOPKG; > + goto err; > + } > + > + /* Request enough space for the ASN.1 template + input hash > */ > + asn1_wrapped = kzalloc(in_len + asn1->size, GFP_KERNEL); > + if (!asn1_wrapped) { > + ret = -ENOMEM; > + goto err; > + } > + > + /* 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; > + } > + > + /* with padding: */ > + padded = kmalloc(pub_len, GFP_KERNEL); > + tpm2_pad_pkcs1(in, in_len, padded, pub_len); > + ret = __tpm2_key_rsa_decrypt(chip, key, params, padded, pub_len, > out); > + kfree(padded); > + > +err: > + kfree(asn1_wrapped); > + return ret; > +} > + > +static void tpm2_key_rsa_describe(const struct key *asymmetric_key, > + struct seq_file *m) > +{ > + struct tpm2_key_rsa *key = asymmetric_key- > >payload.data[asym_crypto]; > + > + if (!key) { > + pr_err("key blob missing"); > + 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); > + kfree(key); > +} > + > +static int tpm2_key_rsa_eds_op(struct kernel_pkey_params *params, > + const void *in, void *out) > +{ > + struct tpm2_key_rsa *key = params->key- > >payload.data[asym_crypto]; > + struct tpm_chip *chip = tpm_default_chip(); > + > + if (!chip) > + return -ENODEV; > + > + switch (params->op) { > + case kernel_pkey_encrypt: > + return tpm2_key_rsa_encrypt(key, params, in, out); > + case kernel_pkey_decrypt: > + return tpm2_key_rsa_decrypt(chip, key, params, in, out); > + case kernel_pkey_sign: > + return tpm2_key_rsa_sign(chip, key, params, in, out); > + default: > + return -EOPNOTSUPP; > + } > +} > + > +static int tpm2_key_rsa_verify(const struct key *key, > + const struct public_key_signature *sig) > +{ > + const struct tpm2_key_rsa *tpm2_key = key- > >payload.data[asym_crypto]; > + char alg_name[CRYPTO_MAX_ALG_NAME]; > + u8 enc_pub_key[PUB_KEY_BUF_SIZE]; > + struct akcipher_request *req; > + struct scatterlist src_sg[2]; > + struct crypto_akcipher *tfm; > + struct crypto_wait cwait; > + int rc; > + > + if (!sig->digest) > + return -ENOPKG; > + > + rc = tpm2_key_get_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); > + > + rc = tpm2_key_rsa_encode(tpm2_key, enc_pub_key); > + if (rc < 0) > + goto err_tfm; > + > + rc = crypto_akcipher_set_pub_key(tfm, enc_pub_key, rc); > + 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); > + return rc; > +} > + > +static int tpm2_key_rsa_query(const struct kernel_pkey_params *params, > + struct kernel_pkey_query *info) > +{ > + struct tpm2_key_rsa *tk = params->key->payload.data[asym_crypto]; > + char alg_name[CRYPTO_MAX_ALG_NAME]; > + u8 enc_pub_key[PUB_KEY_BUF_SIZE]; > + struct crypto_akcipher *tfm; > + unsigned int len; > + int ret; > + > + ret = tpm2_key_get_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); > + > + ret = tpm2_key_rsa_encode(tk, enc_pub_key); > + if (ret < 0) > + goto err_tfm; > + > + ret = crypto_akcipher_set_pub_key(tfm, enc_pub_key, ret); > + 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_rsa *key; > + int ret; > + > + key = kzalloc(sizeof(*key), GFP_KERNEL); > + if (!key) > + return -ENOMEM; > + > + /* > + * 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) { > + kfree(key); > + return -EMSGSIZE; > + } > + > + ret = tpm2_key_decode(prep->data, prep->datalen, &key->key, > PAGE_SIZE); > + if (ret) { > + kfree(key); > + return ret; > + } > + > + if (key->key.oid != OID_TPMLoadableKey) { > + tpm2_key_destroy(&key->key); > + kfree(key); > + return -EINVAL; > + } > + > + ret = tpm2_key_rsa_extract_pub(key); > + if (ret < 0) { > + tpm2_key_destroy(&key->key); > + kfree(key); > + return ret; > + } > + > + prep->payload.data[asym_subtype] = &tpm2_key_rsa_subtype; > + prep->payload.data[asym_key_ids] = NULL; > + prep->payload.data[asym_crypto] = key; > + 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_rsa_parser); > +} > + > +static void __exit tpm2_key_rsa_exit(void) > +{ > + unregister_asymmetric_key_parser(&tpm2_key_rsa_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/include/linux/tpm.h b/include/linux/tpm.h > index 2f25ca07127b..8161758da19a 100644 > --- a/include/linux/tpm.h > +++ b/include/linux/tpm.h > @@ -43,6 +43,7 @@ enum tpm2_session_types { > /* if you add a new hash to this, increment TPM_MAX_HASHES below */ > enum tpm_algorithms { > TPM_ALG_ERROR = 0x0000, > + TPM_ALG_RSA = 0x0001, > TPM_ALG_SHA1 = 0x0004, > TPM_ALG_AES = 0x0006, > TPM_ALG_KEYEDHASH = 0x0008, > @@ -271,6 +272,7 @@ 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, > -- > 2.45.1 >
On Tue May 21, 2024 at 10:25 AM EEST, Bharat Bhushan wrote: > > + rc = crypto_akcipher_encrypt(req); > > + rc = crypto_wait_req(rc, &cwait); > > + > > Few Minor comments, > Extra line here Yeah, makes sense. > > + if (!rc) > > + rc = req->dst_len; > > + > > + akcipher_request_free(req); > > + > > +err_tfm: > > + crypto_free_akcipher(tfm); > > + > > + return rc; > > +} > > + > > +static int __tpm2_key_rsa_decrypt(struct tpm_chip *chip, > > + struct tpm2_key_rsa *key, > > + struct kernel_pkey_params *params, > > + const void *in, int in_len, void *out) > > +{ > > + unsigned int offset = 0; > > + u32 key_handle = 0; > > + struct tpm_buf buf; > > + u16 decrypted_len; > > + u32 parent; > > + u8 *pos; > > + int ret; > > + > > + ret = tpm_try_get_ops(chip); > > + if (ret) > > + return ret; > > + > > + ret = tpm2_start_auth_session(chip); > > + if (ret) > > + goto err_ops; > > + > > + if (key->key.parent == TPM2_RH_NULL) { > > + ret = tpm2_load_context(chip, chip->null_key_context, > > &offset, > > + &parent); > > + if (ret) { > > + ret = -EIO; > > + goto err_auth; > > + } > > + } else { > > + parent = key->key.parent; > > + } > > Do we need braces here? I think I added them because checkpatch complained me about not having them. So I guess the rule is that if any branch has braces, all of them should have... > > > + > > + ret = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD); > > + if (ret < 0) > > + goto err_parent; > > + > > + tpm_buf_append_name(chip, &buf, parent, NULL); > > + tpm_buf_append_hmac_session(chip, &buf, > > TPM2_SA_CONTINUE_SESSION | > > + TPM2_SA_ENCRYPT, NULL, 0); > > + tpm_buf_append(&buf, key->key.blob, key->key.blob_len); > > + 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, "RSA key loading"); > > + ret = tpm_buf_check_hmac_response(chip, &buf, ret); > > + if (ret) { > > + ret = -EIO; > > + goto err_buf; > > + } > > + key_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, key_handle, NULL); > > + tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT, > > NULL, 0); > > + tpm_buf_append_u16(&buf, in_len); > > + tpm_buf_append(&buf, in, in_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, "RSA key decrypting"); > > + 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; > > + > > + if (params->out_len < decrypted_len) { > > + ret = -EMSGSIZE; > > + goto err_blob; > > + } > > + > > + memcpy(out, pos, decrypted_len); > > + ret = decrypted_len; > > + > > +err_blob: > > + tpm2_flush_context(chip, key_handle); > > + > > +err_buf: > > + tpm_buf_destroy(&buf); > > + > > +err_parent: > > + if (key->key.parent == TPM2_RH_NULL) > > + tpm2_flush_context(chip, parent); > > + > > +err_auth: > > + if (ret < 0) > > + tpm2_end_auth_session(chip); > > + > > +err_ops: > > + tpm_put_ops(chip); > > + return ret; > > +} > > + > > +static int tpm2_key_rsa_decrypt(struct tpm_chip *chip, struct tpm2_key_rsa > > *key, > > + struct kernel_pkey_params *params, > > + const void *in, void *out) > > +{ > > + const u8 *ptr; > > + int out_len; > > + u8 *work; > > + int ret; > > + > > + work = kzalloc(params->out_len, GFP_KERNEL); > > + if (!work) > > + return -ENOMEM; > > Maybe use ERR_PTR() here and couple of more places Hmm... but the function returns 'int'? BR, Jarkko
diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig index e1345b8f39f1..4d14bb0c346e 100644 --- a/crypto/asymmetric_keys/Kconfig +++ b/crypto/asymmetric_keys/Kconfig @@ -15,6 +15,7 @@ config ASYMMETRIC_PUBLIC_KEY_SUBTYPE select MPILIB select CRYPTO_HASH_INFO select CRYPTO_AKCIPHER + select CRYPTO_RSA select CRYPTO_SIG select CRYPTO_HASH help @@ -23,6 +24,21 @@ 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 + select TCG_TPM2_HMAC + select CRYPTO_RSA + select CRYPTO_SHA256 + select CRYPTO_HASH_INFO + select ASN1 + select ASN1_ENCODER + 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..c6da84607824 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_RSA_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..32250ff38268 --- /dev/null +++ b/crypto/asymmetric_keys/tpm2_key_rsa.c @@ -0,0 +1,698 @@ +// 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 + */ + +#include <asm/unaligned.h> +#include <crypto/akcipher.h> +#include <crypto/public_key.h> +#include <crypto/rsa-pkcs1pad.h> +#include <crypto/tpm2_key.h> +#include <keys/asymmetric-parser.h> +#include <keys/asymmetric-subtype.h> +#include <keys/trusted-type.h> +#include <linux/asn1_encoder.h> +#include <linux/keyctl.h> +#include <linux/module.h> +#include <linux/scatterlist.h> +#include <linux/slab.h> +#include <linux/tpm.h> + +#undef pr_fmt +#define pr_fmt(fmt) "tpm2_key_rsa: "fmt + +#define PUB_KEY_BUF_SIZE 512 + +struct tpm2_key_rsa { + struct tpm2_key key; + const u8 *pub; + int pub_len; +}; + +static const int PKCS1_PAD_MIN_SIZE = 11; + +/* + * Fill the data with PKCS#1 v1.5 padding. + */ +static int tpm2_pad_pkcs1(const u8 *in, int in_len, u8 *out, int out_len) +{ + unsigned int prefix_len = out_len - in_len - 3; + + if (in_len > out_len - PKCS1_PAD_MIN_SIZE) + return -EBADMSG; + + /* prefix */ + out[0] = 0; + out[1] = 1; + memset(&out[2], 0xff, prefix_len); + out[2 + prefix_len] = 0; + /* payload */ + memcpy(&out[2 + prefix_len + 1], in, in_len); + + return 0; +} + +/* + * RFC 3447 - Section 7.2.2 + * Size of the input data should be checked against public key size by + * the caller. + */ +static const u8 *tpm2_unpad_pkcs1(const u8 *in, int in_len, int *out_len) +{ + int i; + + if (in[0] != 0 || in[1] != 2) + return NULL; + + i = 2; + while (in[i] != 0 && i < in_len) + i++; + + if (i == in_len || i < (PKCS1_PAD_MIN_SIZE - 1)) + return NULL; + + *out_len = in_len - i - 1; + return in + 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) { + strcpy(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) { + strcpy(cipher, "rsa"); + return 0; + } + + return -ENOPKG; +} + +static int tpm2_key_rsa_extract_pub(struct tpm2_key_rsa *key_rsa) +{ + struct tpm2_key *key = &key_rsa->key; + struct tpm_buf buf; + off_t offset = 2; + u16 policy_len; + u32 attr; + u16 bits; + u16 type; + u16 len; + u16 alg; + u32 exp; + + buf.flags = TPM_BUF_TPM2B; + buf.length = key->pub_len; + buf.data = (void *)key->pub; + + if (get_unaligned_be16(key->pub) != buf.length - 2) + return -EINVAL; + + type = tpm_buf_read_u16(&buf, &offset); + pr_debug("pub type: 0x%04x\n", type); + if (type != TPM_ALG_RSA) + return -EINVAL; + + alg = tpm_buf_read_u16(&buf, &offset); + pr_debug("pub name alg: 0x%04x\n", alg); + attr = tpm_buf_read_u32(&buf, &offset); + pr_debug("pub attributes: 0x%08x\n", attr); + policy_len = tpm_buf_read_u16(&buf, &offset); + pr_debug("pub policy length: %u bytes\n", policy_len); + offset += policy_len; + + alg = tpm_buf_read_u16(&buf, &offset); + pr_debug("pub symmetric: 0x%04x\n", alg); + if (alg != TPM_ALG_NULL) + return -EINVAL; + + alg = tpm_buf_read_u16(&buf, &offset); + pr_debug("pub symmetric scheme: 0x%04x\n", alg); + if (alg != TPM_ALG_NULL) + return -EINVAL; + + bits = tpm_buf_read_u16(&buf, &offset); + pr_debug("pub bits: %u\n", bits); + + exp = tpm_buf_read_u32(&buf, &offset); + pr_debug("pub exponent: 0x%08x\n", exp); + if (exp != 0x00000000 && exp != 0x00010001) + return -EINVAL; + + len = tpm_buf_read_u16(&buf, &offset); + pr_debug("pub modulus: %u bytes\n", len); + key_rsa->pub = key->pub + offset; + key_rsa->pub_len = len; + + return buf.flags & TPM_BUF_BOUNDARY_ERROR ? -EIO : 0; +} + +static int tpm2_key_rsa_encode(const struct tpm2_key_rsa *key, u8 *buf) +{ + const int SCRATCH_SIZE = PAGE_SIZE; + const u8 exp[3] = {1, 0, 1}; + u8 *scratch, *work, *work1, *end_work; + int pub_len = key->pub_len; + const u8 *pub = key->pub; + int ret; + + scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL); + if (!scratch) + return -ENOMEM; + + work = scratch; + end_work = &scratch[SCRATCH_SIZE]; + + work = asn1_encode_integer(work, end_work, pub, pub_len); + if (IS_ERR(work)) { + ret = PTR_ERR(work); + goto err; + } + + work = asn1_encode_integer(work, end_work, exp, 3); + if (IS_ERR(work)) { + ret = PTR_ERR(work); + goto err; + } + + work1 = buf; + work1 = asn1_encode_sequence(work1, &work1[PUB_KEY_BUF_SIZE], + scratch, work - scratch); + if (IS_ERR(work1)) { + ret = PTR_ERR(work1); + goto err; + } + + memset(work1, 0, 8); + + kfree(scratch); + return work1 - buf; + +err: + kfree(scratch); + return ret; +} + +/* + * Encryption operation is performed with the public key. Hence it is done + * in software + */ +static int tpm2_key_rsa_encrypt(struct tpm2_key_rsa *key, + struct kernel_pkey_params *params, + const void *in, void *out) +{ + char cipher[CRYPTO_MAX_ALG_NAME]; + struct scatterlist in_sg, out_sg; + u8 enc_pub_key[PUB_KEY_BUF_SIZE]; + struct akcipher_request *req; + struct crypto_akcipher *tfm; + struct crypto_wait cwait; + 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); + + rc = tpm2_key_rsa_encode(key, enc_pub_key); + if (rc < 0) + goto err_tfm; + + rc = crypto_akcipher_set_pub_key(tfm, enc_pub_key, rc); + 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; +} + +static int __tpm2_key_rsa_decrypt(struct tpm_chip *chip, + struct tpm2_key_rsa *key, + struct kernel_pkey_params *params, + const void *in, int in_len, void *out) +{ + unsigned int offset = 0; + u32 key_handle = 0; + struct tpm_buf buf; + u16 decrypted_len; + u32 parent; + u8 *pos; + int ret; + + ret = tpm_try_get_ops(chip); + if (ret) + return ret; + + ret = tpm2_start_auth_session(chip); + if (ret) + goto err_ops; + + if (key->key.parent == TPM2_RH_NULL) { + ret = tpm2_load_context(chip, chip->null_key_context, &offset, + &parent); + if (ret) { + ret = -EIO; + goto err_auth; + } + } else { + parent = key->key.parent; + } + + ret = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD); + if (ret < 0) + goto err_parent; + + tpm_buf_append_name(chip, &buf, parent, NULL); + tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_CONTINUE_SESSION | + TPM2_SA_ENCRYPT, NULL, 0); + tpm_buf_append(&buf, key->key.blob, key->key.blob_len); + 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, "RSA key loading"); + ret = tpm_buf_check_hmac_response(chip, &buf, ret); + if (ret) { + ret = -EIO; + goto err_buf; + } + key_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, key_handle, NULL); + tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT, NULL, 0); + tpm_buf_append_u16(&buf, in_len); + tpm_buf_append(&buf, in, in_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, "RSA key decrypting"); + 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; + + if (params->out_len < decrypted_len) { + ret = -EMSGSIZE; + goto err_blob; + } + + memcpy(out, pos, decrypted_len); + ret = decrypted_len; + +err_blob: + tpm2_flush_context(chip, key_handle); + +err_buf: + tpm_buf_destroy(&buf); + +err_parent: + if (key->key.parent == TPM2_RH_NULL) + tpm2_flush_context(chip, parent); + +err_auth: + if (ret < 0) + tpm2_end_auth_session(chip); + +err_ops: + tpm_put_ops(chip); + return ret; +} + +static int tpm2_key_rsa_decrypt(struct tpm_chip *chip, struct tpm2_key_rsa *key, + struct kernel_pkey_params *params, + const void *in, void *out) +{ + const u8 *ptr; + int out_len; + u8 *work; + int ret; + + work = kzalloc(params->out_len, GFP_KERNEL); + if (!work) + return -ENOMEM; + + ret = __tpm2_key_rsa_decrypt(chip, key, params, in, params->in_len, + work); + if (ret < 0) + goto err; + + ptr = tpm2_unpad_pkcs1(work, ret, &out_len); + if (!ptr) { + ret = -EINVAL; + goto err; + } + + if (out_len > params->out_len) { + ret = -EMSGSIZE; + goto err; + } + + memcpy(out, ptr, out_len); + kfree(work); + return out_len; + +err: + kfree(work); + return ret; +} + +/* + * 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_rsa *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; + int pub_len = key->pub_len; + u8 *padded; + int ret; + + if (strcmp(params->encoding, "pkcs1") != 0) { + ret = -ENOPKG; + goto err; + } + + if (params->hash_algo) { + asn1 = rsa_lookup_asn1(params->hash_algo); + if (!asn1) { + ret = -ENOPKG; + goto err; + } + + /* Request enough space for the ASN.1 template + input hash */ + asn1_wrapped = kzalloc(in_len + asn1->size, GFP_KERNEL); + if (!asn1_wrapped) { + ret = -ENOMEM; + goto err; + } + + /* 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; + } + + /* with padding: */ + padded = kmalloc(pub_len, GFP_KERNEL); + tpm2_pad_pkcs1(in, in_len, padded, pub_len); + ret = __tpm2_key_rsa_decrypt(chip, key, params, padded, pub_len, out); + kfree(padded); + +err: + kfree(asn1_wrapped); + return ret; +} + +static void tpm2_key_rsa_describe(const struct key *asymmetric_key, + struct seq_file *m) +{ + struct tpm2_key_rsa *key = asymmetric_key->payload.data[asym_crypto]; + + if (!key) { + pr_err("key blob missing"); + 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); + kfree(key); +} + +static int tpm2_key_rsa_eds_op(struct kernel_pkey_params *params, + const void *in, void *out) +{ + struct tpm2_key_rsa *key = params->key->payload.data[asym_crypto]; + struct tpm_chip *chip = tpm_default_chip(); + + if (!chip) + return -ENODEV; + + switch (params->op) { + case kernel_pkey_encrypt: + return tpm2_key_rsa_encrypt(key, params, in, out); + case kernel_pkey_decrypt: + return tpm2_key_rsa_decrypt(chip, key, params, in, out); + case kernel_pkey_sign: + return tpm2_key_rsa_sign(chip, key, params, in, out); + default: + return -EOPNOTSUPP; + } +} + +static int tpm2_key_rsa_verify(const struct key *key, + const struct public_key_signature *sig) +{ + const struct tpm2_key_rsa *tpm2_key = key->payload.data[asym_crypto]; + char alg_name[CRYPTO_MAX_ALG_NAME]; + u8 enc_pub_key[PUB_KEY_BUF_SIZE]; + struct akcipher_request *req; + struct scatterlist src_sg[2]; + struct crypto_akcipher *tfm; + struct crypto_wait cwait; + int rc; + + if (!sig->digest) + return -ENOPKG; + + rc = tpm2_key_get_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); + + rc = tpm2_key_rsa_encode(tpm2_key, enc_pub_key); + if (rc < 0) + goto err_tfm; + + rc = crypto_akcipher_set_pub_key(tfm, enc_pub_key, rc); + 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); + return rc; +} + +static int tpm2_key_rsa_query(const struct kernel_pkey_params *params, + struct kernel_pkey_query *info) +{ + struct tpm2_key_rsa *tk = params->key->payload.data[asym_crypto]; + char alg_name[CRYPTO_MAX_ALG_NAME]; + u8 enc_pub_key[PUB_KEY_BUF_SIZE]; + struct crypto_akcipher *tfm; + unsigned int len; + int ret; + + ret = tpm2_key_get_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); + + ret = tpm2_key_rsa_encode(tk, enc_pub_key); + if (ret < 0) + goto err_tfm; + + ret = crypto_akcipher_set_pub_key(tfm, enc_pub_key, ret); + 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_rsa *key; + int ret; + + key = kzalloc(sizeof(*key), GFP_KERNEL); + if (!key) + return -ENOMEM; + + /* + * 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) { + kfree(key); + return -EMSGSIZE; + } + + ret = tpm2_key_decode(prep->data, prep->datalen, &key->key, PAGE_SIZE); + if (ret) { + kfree(key); + return ret; + } + + if (key->key.oid != OID_TPMLoadableKey) { + tpm2_key_destroy(&key->key); + kfree(key); + return -EINVAL; + } + + ret = tpm2_key_rsa_extract_pub(key); + if (ret < 0) { + tpm2_key_destroy(&key->key); + kfree(key); + return ret; + } + + prep->payload.data[asym_subtype] = &tpm2_key_rsa_subtype; + prep->payload.data[asym_key_ids] = NULL; + prep->payload.data[asym_crypto] = key; + 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_rsa_parser); +} + +static void __exit tpm2_key_rsa_exit(void) +{ + unregister_asymmetric_key_parser(&tpm2_key_rsa_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/include/linux/tpm.h b/include/linux/tpm.h index 2f25ca07127b..8161758da19a 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -43,6 +43,7 @@ enum tpm2_session_types { /* if you add a new hash to this, increment TPM_MAX_HASHES below */ enum tpm_algorithms { TPM_ALG_ERROR = 0x0000, + TPM_ALG_RSA = 0x0001, TPM_ALG_SHA1 = 0x0004, TPM_ALG_AES = 0x0006, TPM_ALG_KEYEDHASH = 0x0008, @@ -271,6 +272,7 @@ 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,