diff options
Diffstat (limited to '')
| -rw-r--r-- | security/keys/trusted-keys/trusted_tpm1.c | 1074 |
1 files changed, 1074 insertions, 0 deletions
diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c new file mode 100644 index 000000000..aa108bea6 --- /dev/null +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -0,0 +1,1074 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2010 IBM Corporation + * Copyright (c) 2019-2021, Linaro Limited + * + * See Documentation/security/keys/trusted-encrypted.rst + */ + +#include <crypto/hash_info.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/parser.h> +#include <linux/string.h> +#include <linux/err.h> +#include <keys/trusted-type.h> +#include <linux/key-type.h> +#include <linux/crypto.h> +#include <crypto/hash.h> +#include <crypto/sha1.h> +#include <linux/tpm.h> +#include <linux/tpm_command.h> + +#include <keys/trusted_tpm.h> + +static const char hmac_alg[] = "hmac(sha1)"; +static const char hash_alg[] = "sha1"; +static struct tpm_chip *chip; +static struct tpm_digest *digests; + +struct sdesc { + struct shash_desc shash; + char ctx[]; +}; + +static struct crypto_shash *hashalg; +static struct crypto_shash *hmacalg; + +static struct sdesc *init_sdesc(struct crypto_shash *alg) +{ + struct sdesc *sdesc; + int size; + + size = sizeof(struct shash_desc) + crypto_shash_descsize(alg); + sdesc = kmalloc(size, GFP_KERNEL); + if (!sdesc) + return ERR_PTR(-ENOMEM); + sdesc->shash.tfm = alg; + return sdesc; +} + +static int TSS_sha1(const unsigned char *data, unsigned int datalen, + unsigned char *digest) +{ + struct sdesc *sdesc; + int ret; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + + ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest); + kfree_sensitive(sdesc); + return ret; +} + +static int TSS_rawhmac(unsigned char *digest, const unsigned char *key, + unsigned int keylen, ...) +{ + struct sdesc *sdesc; + va_list argp; + unsigned int dlen; + unsigned char *data; + int ret; + + sdesc = init_sdesc(hmacalg); + if (IS_ERR(sdesc)) { + pr_info("can't alloc %s\n", hmac_alg); + return PTR_ERR(sdesc); + } + + ret = crypto_shash_setkey(hmacalg, key, keylen); + if (ret < 0) + goto out; + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + + va_start(argp, keylen); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + data = va_arg(argp, unsigned char *); + if (data == NULL) { + ret = -EINVAL; + break; + } + ret = crypto_shash_update(&sdesc->shash, data, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, digest); +out: + kfree_sensitive(sdesc); + return ret; +} + +/* + * calculate authorization info fields to send to TPM + */ +int TSS_authhmac(unsigned char *digest, const unsigned char *key, + unsigned int keylen, unsigned char *h1, + unsigned char *h2, unsigned int h3, ...) +{ + unsigned char paramdigest[SHA1_DIGEST_SIZE]; + struct sdesc *sdesc; + unsigned int dlen; + unsigned char *data; + unsigned char c; + int ret; + va_list argp; + + if (!chip) + return -ENODEV; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + + c = !!h3; + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + va_start(argp, h3); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + data = va_arg(argp, unsigned char *); + if (!data) { + ret = -EINVAL; + break; + } + ret = crypto_shash_update(&sdesc->shash, data, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, paramdigest); + if (!ret) + ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE, + paramdigest, TPM_NONCE_SIZE, h1, + TPM_NONCE_SIZE, h2, 1, &c, 0, 0); +out: + kfree_sensitive(sdesc); + return ret; +} +EXPORT_SYMBOL_GPL(TSS_authhmac); + +/* + * verify the AUTH1_COMMAND (Seal) result from TPM + */ +int TSS_checkhmac1(unsigned char *buffer, + const uint32_t command, + const unsigned char *ononce, + const unsigned char *key, + unsigned int keylen, ...) +{ + uint32_t bufsize; + uint16_t tag; + uint32_t ordinal; + uint32_t result; + unsigned char *enonce; + unsigned char *continueflag; + unsigned char *authdata; + unsigned char testhmac[SHA1_DIGEST_SIZE]; + unsigned char paramdigest[SHA1_DIGEST_SIZE]; + struct sdesc *sdesc; + unsigned int dlen; + unsigned int dpos; + va_list argp; + int ret; + + if (!chip) + return -ENODEV; + + bufsize = LOAD32(buffer, TPM_SIZE_OFFSET); + tag = LOAD16(buffer, 0); + ordinal = command; + result = LOAD32N(buffer, TPM_RETURN_OFFSET); + if (tag == TPM_TAG_RSP_COMMAND) + return 0; + if (tag != TPM_TAG_RSP_AUTH1_COMMAND) + return -EINVAL; + authdata = buffer + bufsize - SHA1_DIGEST_SIZE; + continueflag = authdata - 1; + enonce = continueflag - TPM_NONCE_SIZE; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result, + sizeof result); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal, + sizeof ordinal); + if (ret < 0) + goto out; + va_start(argp, keylen); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + dpos = va_arg(argp, unsigned int); + ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, paramdigest); + if (ret < 0) + goto out; + + ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest, + TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce, + 1, continueflag, 0, 0); + if (ret < 0) + goto out; + + if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE)) + ret = -EINVAL; +out: + kfree_sensitive(sdesc); + return ret; +} +EXPORT_SYMBOL_GPL(TSS_checkhmac1); + +/* + * verify the AUTH2_COMMAND (unseal) result from TPM + */ +static int TSS_checkhmac2(unsigned char *buffer, + const uint32_t command, + const unsigned char *ononce, + const unsigned char *key1, + unsigned int keylen1, + const unsigned char *key2, + unsigned int keylen2, ...) +{ + uint32_t bufsize; + uint16_t tag; + uint32_t ordinal; + uint32_t result; + unsigned char *enonce1; + unsigned char *continueflag1; + unsigned char *authdata1; + unsigned char *enonce2; + unsigned char *continueflag2; + unsigned char *authdata2; + unsigned char testhmac1[SHA1_DIGEST_SIZE]; + unsigned char testhmac2[SHA1_DIGEST_SIZE]; + unsigned char paramdigest[SHA1_DIGEST_SIZE]; + struct sdesc *sdesc; + unsigned int dlen; + unsigned int dpos; + va_list argp; + int ret; + + bufsize = LOAD32(buffer, TPM_SIZE_OFFSET); + tag = LOAD16(buffer, 0); + ordinal = command; + result = LOAD32N(buffer, TPM_RETURN_OFFSET); + + if (tag == TPM_TAG_RSP_COMMAND) + return 0; + if (tag != TPM_TAG_RSP_AUTH2_COMMAND) + return -EINVAL; + authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1 + + SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE); + authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE); + continueflag1 = authdata1 - 1; + continueflag2 = authdata2 - 1; + enonce1 = continueflag1 - TPM_NONCE_SIZE; + enonce2 = continueflag2 - TPM_NONCE_SIZE; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result, + sizeof result); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal, + sizeof ordinal); + if (ret < 0) + goto out; + + va_start(argp, keylen2); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + dpos = va_arg(argp, unsigned int); + ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, paramdigest); + if (ret < 0) + goto out; + + ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE, + paramdigest, TPM_NONCE_SIZE, enonce1, + TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0); + if (ret < 0) + goto out; + if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) { + ret = -EINVAL; + goto out; + } + ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE, + paramdigest, TPM_NONCE_SIZE, enonce2, + TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0); + if (ret < 0) + goto out; + if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE)) + ret = -EINVAL; +out: + kfree_sensitive(sdesc); + return ret; +} + +/* + * For key specific tpm requests, we will generate and send our + * own TPM command packets using the drivers send function. + */ +int trusted_tpm_send(unsigned char *cmd, size_t buflen) +{ + int rc; + + if (!chip) + return -ENODEV; + + dump_tpm_buf(cmd); + rc = tpm_send(chip, cmd, buflen); + dump_tpm_buf(cmd); + if (rc > 0) + /* Can't return positive return codes values to keyctl */ + rc = -EPERM; + return rc; +} +EXPORT_SYMBOL_GPL(trusted_tpm_send); + +/* + * Lock a trusted key, by extending a selected PCR. + * + * Prevents a trusted key that is sealed to PCRs from being accessed. + * This uses the tpm driver's extend function. + */ +static int pcrlock(const int pcrnum) +{ + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + return tpm_pcr_extend(chip, pcrnum, digests) ? -EINVAL : 0; +} + +/* + * Create an object specific authorisation protocol (OSAP) session + */ +static int osap(struct tpm_buf *tb, struct osapsess *s, + const unsigned char *key, uint16_t type, uint32_t handle) +{ + unsigned char enonce[TPM_NONCE_SIZE]; + unsigned char ononce[TPM_NONCE_SIZE]; + int ret; + + ret = tpm_get_random(chip, ononce, TPM_NONCE_SIZE); + if (ret < 0) + return ret; + + if (ret != TPM_NONCE_SIZE) + return -EIO; + + tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_OSAP); + tpm_buf_append_u16(tb, type); + tpm_buf_append_u32(tb, handle); + tpm_buf_append(tb, ononce, TPM_NONCE_SIZE); + + ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); + if (ret < 0) + return ret; + + s->handle = LOAD32(tb->data, TPM_DATA_OFFSET); + memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]), + TPM_NONCE_SIZE); + memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) + + TPM_NONCE_SIZE]), TPM_NONCE_SIZE); + return TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE, + enonce, TPM_NONCE_SIZE, ononce, 0, 0); +} + +/* + * Create an object independent authorisation protocol (oiap) session + */ +int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce) +{ + int ret; + + if (!chip) + return -ENODEV; + + tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_OIAP); + ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); + if (ret < 0) + return ret; + + *handle = LOAD32(tb->data, TPM_DATA_OFFSET); + memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)], + TPM_NONCE_SIZE); + return 0; +} +EXPORT_SYMBOL_GPL(oiap); + +struct tpm_digests { + unsigned char encauth[SHA1_DIGEST_SIZE]; + unsigned char pubauth[SHA1_DIGEST_SIZE]; + unsigned char xorwork[SHA1_DIGEST_SIZE * 2]; + unsigned char xorhash[SHA1_DIGEST_SIZE]; + unsigned char nonceodd[TPM_NONCE_SIZE]; +}; + +/* + * Have the TPM seal(encrypt) the trusted key, possibly based on + * Platform Configuration Registers (PCRs). AUTH1 for sealing key. + */ +static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, + uint32_t keyhandle, const unsigned char *keyauth, + const unsigned char *data, uint32_t datalen, + unsigned char *blob, uint32_t *bloblen, + const unsigned char *blobauth, + const unsigned char *pcrinfo, uint32_t pcrinfosize) +{ + struct osapsess sess; + struct tpm_digests *td; + unsigned char cont; + uint32_t ordinal; + uint32_t pcrsize; + uint32_t datsize; + int sealinfosize; + int encdatasize; + int storedsize; + int ret; + int i; + + /* alloc some work space for all the hashes */ + td = kmalloc(sizeof *td, GFP_KERNEL); + if (!td) + return -ENOMEM; + + /* get session for sealing key */ + ret = osap(tb, &sess, keyauth, keytype, keyhandle); + if (ret < 0) + goto out; + dump_sess(&sess); + + /* calculate encrypted authorization value */ + memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE); + memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE); + ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash); + if (ret < 0) + goto out; + + ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE); + if (ret < 0) + goto out; + + if (ret != TPM_NONCE_SIZE) { + ret = -EIO; + goto out; + } + + ordinal = htonl(TPM_ORD_SEAL); + datsize = htonl(datalen); + pcrsize = htonl(pcrinfosize); + cont = 0; + + /* encrypt data authorization key */ + for (i = 0; i < SHA1_DIGEST_SIZE; ++i) + td->encauth[i] = td->xorhash[i] ^ blobauth[i]; + + /* calculate authorization HMAC value */ + if (pcrinfosize == 0) { + /* no pcr info specified */ + ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE, + sess.enonce, td->nonceodd, cont, + sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE, + td->encauth, sizeof(uint32_t), &pcrsize, + sizeof(uint32_t), &datsize, datalen, data, 0, + 0); + } else { + /* pcr info specified */ + ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE, + sess.enonce, td->nonceodd, cont, + sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE, + td->encauth, sizeof(uint32_t), &pcrsize, + pcrinfosize, pcrinfo, sizeof(uint32_t), + &datsize, datalen, data, 0, 0); + } + if (ret < 0) + goto out; + + /* build and send the TPM request packet */ + tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_SEAL); + tpm_buf_append_u32(tb, keyhandle); + tpm_buf_append(tb, td->encauth, SHA1_DIGEST_SIZE); + tpm_buf_append_u32(tb, pcrinfosize); + tpm_buf_append(tb, pcrinfo, pcrinfosize); + tpm_buf_append_u32(tb, datalen); + tpm_buf_append(tb, data, datalen); + tpm_buf_append_u32(tb, sess.handle); + tpm_buf_append(tb, td->nonceodd, TPM_NONCE_SIZE); + tpm_buf_append_u8(tb, cont); + tpm_buf_append(tb, td->pubauth, SHA1_DIGEST_SIZE); + + ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); + if (ret < 0) + goto out; + + /* calculate the size of the returned Blob */ + sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t)); + encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) + + sizeof(uint32_t) + sealinfosize); + storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize + + sizeof(uint32_t) + encdatasize; + + /* check the HMAC in the response */ + ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret, + SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0, + 0); + + /* copy the returned blob to caller */ + if (!ret) { + memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize); + *bloblen = storedsize; + } +out: + kfree_sensitive(td); + return ret; +} + +/* + * use the AUTH2_COMMAND form of unseal, to authorize both key and blob + */ +static int tpm_unseal(struct tpm_buf *tb, + uint32_t keyhandle, const unsigned char *keyauth, + const unsigned char *blob, int bloblen, + const unsigned char *blobauth, + unsigned char *data, unsigned int *datalen) +{ + unsigned char nonceodd[TPM_NONCE_SIZE]; + unsigned char enonce1[TPM_NONCE_SIZE]; + unsigned char enonce2[TPM_NONCE_SIZE]; + unsigned char authdata1[SHA1_DIGEST_SIZE]; + unsigned char authdata2[SHA1_DIGEST_SIZE]; + uint32_t authhandle1 = 0; + uint32_t authhandle2 = 0; + unsigned char cont = 0; + uint32_t ordinal; + int ret; + + /* sessions for unsealing key and data */ + ret = oiap(tb, &authhandle1, enonce1); + if (ret < 0) { + pr_info("oiap failed (%d)\n", ret); + return ret; + } + ret = oiap(tb, &authhandle2, enonce2); + if (ret < 0) { + pr_info("oiap failed (%d)\n", ret); + return ret; + } + + ordinal = htonl(TPM_ORD_UNSEAL); + ret = tpm_get_random(chip, nonceodd, TPM_NONCE_SIZE); + if (ret < 0) + return ret; + + if (ret != TPM_NONCE_SIZE) { + pr_info("tpm_get_random failed (%d)\n", ret); + return -EIO; + } + ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE, + enonce1, nonceodd, cont, sizeof(uint32_t), + &ordinal, bloblen, blob, 0, 0); + if (ret < 0) + return ret; + ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE, + enonce2, nonceodd, cont, sizeof(uint32_t), + &ordinal, bloblen, blob, 0, 0); + if (ret < 0) + return ret; + + /* build and send TPM request packet */ + tpm_buf_reset(tb, TPM_TAG_RQU_AUTH2_COMMAND, TPM_ORD_UNSEAL); + tpm_buf_append_u32(tb, keyhandle); + tpm_buf_append(tb, blob, bloblen); + tpm_buf_append_u32(tb, authhandle1); + tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE); + tpm_buf_append_u8(tb, cont); + tpm_buf_append(tb, authdata1, SHA1_DIGEST_SIZE); + tpm_buf_append_u32(tb, authhandle2); + tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE); + tpm_buf_append_u8(tb, cont); + tpm_buf_append(tb, authdata2, SHA1_DIGEST_SIZE); + + ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); + if (ret < 0) { + pr_info("authhmac failed (%d)\n", ret); + return ret; + } + + *datalen = LOAD32(tb->data, TPM_DATA_OFFSET); + ret = TSS_checkhmac2(tb->data, ordinal, nonceodd, + keyauth, SHA1_DIGEST_SIZE, + blobauth, SHA1_DIGEST_SIZE, + sizeof(uint32_t), TPM_DATA_OFFSET, + *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0, + 0); + if (ret < 0) { + pr_info("TSS_checkhmac2 failed (%d)\n", ret); + return ret; + } + memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen); + return 0; +} + +/* + * Have the TPM seal(encrypt) the symmetric key + */ +static int key_seal(struct trusted_key_payload *p, + struct trusted_key_options *o) +{ + struct tpm_buf tb; + int ret; + + ret = tpm_buf_init(&tb, 0, 0); + if (ret) + return ret; + + /* include migratable flag at end of sealed key */ + p->key[p->key_len] = p->migratable; + + ret = tpm_seal(&tb, o->keytype, o->keyhandle, o->keyauth, + p->key, p->key_len + 1, p->blob, &p->blob_len, + o->blobauth, o->pcrinfo, o->pcrinfo_len); + if (ret < 0) + pr_info("srkseal failed (%d)\n", ret); + + tpm_buf_destroy(&tb); + return ret; +} + +/* + * Have the TPM unseal(decrypt) the symmetric key + */ +static int key_unseal(struct trusted_key_payload *p, + struct trusted_key_options *o) +{ + struct tpm_buf tb; + int ret; + + ret = tpm_buf_init(&tb, 0, 0); + if (ret) + return ret; + + ret = tpm_unseal(&tb, o->keyhandle, o->keyauth, p->blob, p->blob_len, + o->blobauth, p->key, &p->key_len); + if (ret < 0) + pr_info("srkunseal failed (%d)\n", ret); + else + /* pull migratable flag out of sealed key */ + p->migratable = p->key[--p->key_len]; + + tpm_buf_destroy(&tb); + return ret; +} + +enum { + Opt_err, + Opt_keyhandle, Opt_keyauth, Opt_blobauth, + Opt_pcrinfo, Opt_pcrlock, Opt_migratable, + Opt_hash, + Opt_policydigest, + Opt_policyhandle, +}; + +static const match_table_t key_tokens = { + {Opt_keyhandle, "keyhandle=%s"}, + {Opt_keyauth, "keyauth=%s"}, + {Opt_blobauth, "blobauth=%s"}, + {Opt_pcrinfo, "pcrinfo=%s"}, + {Opt_pcrlock, "pcrlock=%s"}, + {Opt_migratable, "migratable=%s"}, + {Opt_hash, "hash=%s"}, + {Opt_policydigest, "policydigest=%s"}, + {Opt_policyhandle, "policyhandle=%s"}, + {Opt_err, NULL} +}; + +/* can have zero or more token= options */ +static int getoptions(char *c, struct trusted_key_payload *pay, + struct trusted_key_options *opt) +{ + substring_t args[MAX_OPT_ARGS]; + char *p = c; + int token; + int res; + unsigned long handle; + unsigned long lock; + unsigned long token_mask = 0; + unsigned int digest_len; + int i; + int tpm2; + + tpm2 = tpm_is_tpm2(chip); + if (tpm2 < 0) + return tpm2; + + opt->hash = tpm2 ? HASH_ALGO_SHA256 : HASH_ALGO_SHA1; + + if (!c) + return 0; + + while ((p = strsep(&c, " \t"))) { + if (*p == '\0' || *p == ' ' || *p == '\t') + continue; + token = match_token(p, key_tokens, args); + if (test_and_set_bit(token, &token_mask)) + return -EINVAL; + + switch (token) { + case Opt_pcrinfo: + opt->pcrinfo_len = strlen(args[0].from) / 2; + if (opt->pcrinfo_len > MAX_PCRINFO_SIZE) + return -EINVAL; + res = hex2bin(opt->pcrinfo, args[0].from, + opt->pcrinfo_len); + if (res < 0) + return -EINVAL; + break; + case Opt_keyhandle: + res = kstrtoul(args[0].from, 16, &handle); + if (res < 0) + return -EINVAL; + opt->keytype = SEAL_keytype; + opt->keyhandle = handle; + break; + case Opt_keyauth: + if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE) + return -EINVAL; + res = hex2bin(opt->keyauth, args[0].from, + SHA1_DIGEST_SIZE); + if (res < 0) + return -EINVAL; + break; + case Opt_blobauth: + /* + * TPM 1.2 authorizations are sha1 hashes passed in as + * hex strings. TPM 2.0 authorizations are simple + * passwords (although it can take a hash as well) + */ + opt->blobauth_len = strlen(args[0].from); + + if (opt->blobauth_len == 2 * TPM_DIGEST_SIZE) { + res = hex2bin(opt->blobauth, args[0].from, + TPM_DIGEST_SIZE); + if (res < 0) + return -EINVAL; + + opt->blobauth_len = TPM_DIGEST_SIZE; + break; + } + + if (tpm2 && opt->blobauth_len <= sizeof(opt->blobauth)) { + memcpy(opt->blobauth, args[0].from, + opt->blobauth_len); + break; + } + + return -EINVAL; + + break; + + case Opt_migratable: + if (*args[0].from == '0') + pay->migratable = 0; + else if (*args[0].from != '1') + return -EINVAL; + break; + case Opt_pcrlock: + res = kstrtoul(args[0].from, 10, &lock); + if (res < 0) + return -EINVAL; + opt->pcrlock = lock; + break; + case Opt_hash: + if (test_bit(Opt_policydigest, &token_mask)) + return -EINVAL; + for (i = 0; i < HASH_ALGO__LAST; i++) { + if (!strcmp(args[0].from, hash_algo_name[i])) { + opt->hash = i; + break; + } + } + if (i == HASH_ALGO__LAST) + return -EINVAL; + if (!tpm2 && i != HASH_ALGO_SHA1) { + pr_info("TPM 1.x only supports SHA-1.\n"); + return -EINVAL; + } + break; + case Opt_policydigest: + digest_len = hash_digest_size[opt->hash]; + if (!tpm2 || strlen(args[0].from) != (2 * digest_len)) + return -EINVAL; + res = hex2bin(opt->policydigest, args[0].from, + digest_len); + if (res < 0) + return -EINVAL; + opt->policydigest_len = digest_len; + break; + case Opt_policyhandle: + if (!tpm2) + return -EINVAL; + res = kstrtoul(args[0].from, 16, &handle); + if (res < 0) + return -EINVAL; + opt->policyhandle = handle; + break; + default: + return -EINVAL; + } + } + return 0; +} + +static struct trusted_key_options *trusted_options_alloc(void) +{ + struct trusted_key_options *options; + int tpm2; + + tpm2 = tpm_is_tpm2(chip); + if (tpm2 < 0) + return NULL; + + options = kzalloc(sizeof *options, GFP_KERNEL); + if (options) { + /* set any non-zero defaults */ + options->keytype = SRK_keytype; + + if (!tpm2) + options->keyhandle = SRKHANDLE; + } + return options; +} + +static int trusted_tpm_seal(struct trusted_key_payload *p, char *datablob) +{ + struct trusted_key_options *options = NULL; + int ret = 0; + int tpm2; + + tpm2 = tpm_is_tpm2(chip); + if (tpm2 < 0) + return tpm2; + + options = trusted_options_alloc(); + if (!options) + return -ENOMEM; + + ret = getoptions(datablob, p, options); + if (ret < 0) + goto out; + dump_options(options); + + if (!options->keyhandle && !tpm2) { + ret = -EINVAL; + goto out; + } + + if (tpm2) + ret = tpm2_seal_trusted(chip, p, options); + else + ret = key_seal(p, options); + if (ret < 0) { + pr_info("key_seal failed (%d)\n", ret); + goto out; + } + + if (options->pcrlock) { + ret = pcrlock(options->pcrlock); + if (ret < 0) { + pr_info("pcrlock failed (%d)\n", ret); + goto out; + } + } +out: + kfree_sensitive(options); + return ret; +} + +static int trusted_tpm_unseal(struct trusted_key_payload *p, char *datablob) +{ + struct trusted_key_options *options = NULL; + int ret = 0; + int tpm2; + + tpm2 = tpm_is_tpm2(chip); + if (tpm2 < 0) + return tpm2; + + options = trusted_options_alloc(); + if (!options) + return -ENOMEM; + + ret = getoptions(datablob, p, options); + if (ret < 0) + goto out; + dump_options(options); + + if (!options->keyhandle && !tpm2) { + ret = -EINVAL; + goto out; + } + + if (tpm2) + ret = tpm2_unseal_trusted(chip, p, options); + else + ret = key_unseal(p, options); + if (ret < 0) + pr_info("key_unseal failed (%d)\n", ret); + + if (options->pcrlock) { + ret = pcrlock(options->pcrlock); + if (ret < 0) { + pr_info("pcrlock failed (%d)\n", ret); + goto out; + } + } +out: + kfree_sensitive(options); + return ret; +} + +static int trusted_tpm_get_random(unsigned char *key, size_t key_len) +{ + return tpm_get_random(chip, key, key_len); +} + +static void trusted_shash_release(void) +{ + if (hashalg) + crypto_free_shash(hashalg); + if (hmacalg) + crypto_free_shash(hmacalg); +} + +static int __init trusted_shash_alloc(void) +{ + int ret; + + hmacalg = crypto_alloc_shash(hmac_alg, 0, 0); + if (IS_ERR(hmacalg)) { + pr_info("could not allocate crypto %s\n", + hmac_alg); + return PTR_ERR(hmacalg); + } + + hashalg = crypto_alloc_shash(hash_alg, 0, 0); + if (IS_ERR(hashalg)) { + pr_info("could not allocate crypto %s\n", + hash_alg); + ret = PTR_ERR(hashalg); + goto hashalg_fail; + } + + return 0; + +hashalg_fail: + crypto_free_shash(hmacalg); + return ret; +} + +static int __init init_digests(void) +{ + int i; + + digests = kcalloc(chip->nr_allocated_banks, sizeof(*digests), + GFP_KERNEL); + if (!digests) + return -ENOMEM; + + for (i = 0; i < chip->nr_allocated_banks; i++) + digests[i].alg_id = chip->allocated_banks[i].alg_id; + + return 0; +} + +static int __init trusted_tpm_init(void) +{ + int ret; + + chip = tpm_default_chip(); + if (!chip) + return -ENODEV; + + ret = init_digests(); + if (ret < 0) + goto err_put; + ret = trusted_shash_alloc(); + if (ret < 0) + goto err_free; + ret = register_key_type(&key_type_trusted); + if (ret < 0) + goto err_release; + return 0; +err_release: + trusted_shash_release(); +err_free: + kfree(digests); +err_put: + put_device(&chip->dev); + return ret; +} + +static void trusted_tpm_exit(void) +{ + if (chip) { + put_device(&chip->dev); + kfree(digests); + trusted_shash_release(); + unregister_key_type(&key_type_trusted); + } +} + +struct trusted_key_ops trusted_key_tpm_ops = { + .migratable = 1, /* migratable by default */ + .init = trusted_tpm_init, + .seal = trusted_tpm_seal, + .unseal = trusted_tpm_unseal, + .get_random = trusted_tpm_get_random, + .exit = trusted_tpm_exit, +}; |