123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914915916917918919920921922923924925926927928929930931932933934935936937938939940941942943944945946947948949950951952953954955956957 |
- // SPDX-License-Identifier: GPL-2.0
- #define pr_fmt(fmt) "ASYM-TPM: "fmt
- #include <linux/slab.h>
- #include <linux/module.h>
- #include <linux/export.h>
- #include <linux/kernel.h>
- #include <linux/seq_file.h>
- #include <linux/scatterlist.h>
- #include <linux/tpm.h>
- #include <linux/tpm_command.h>
- #include <crypto/akcipher.h>
- #include <crypto/hash.h>
- #include <crypto/sha.h>
- #include <asm/unaligned.h>
- #include <keys/asymmetric-subtype.h>
- #include <keys/trusted_tpm.h>
- #include <crypto/asym_tpm_subtype.h>
- #include <crypto/public_key.h>
- #define TPM_ORD_FLUSHSPECIFIC 186
- #define TPM_ORD_LOADKEY2 65
- #define TPM_ORD_UNBIND 30
- #define TPM_ORD_SIGN 60
- #define TPM_RT_KEY 0x00000001
- /*
- * Load a TPM key from the blob provided by userspace
- */
- static int tpm_loadkey2(struct tpm_buf *tb,
- uint32_t keyhandle, unsigned char *keyauth,
- const unsigned char *keyblob, int keybloblen,
- uint32_t *newhandle)
- {
- unsigned char nonceodd[TPM_NONCE_SIZE];
- unsigned char enonce[TPM_NONCE_SIZE];
- unsigned char authdata[SHA1_DIGEST_SIZE];
- uint32_t authhandle = 0;
- unsigned char cont = 0;
- uint32_t ordinal;
- int ret;
- ordinal = htonl(TPM_ORD_LOADKEY2);
- /* session for loading the key */
- ret = oiap(tb, &authhandle, enonce);
- if (ret < 0) {
- pr_info("oiap failed (%d)\n", ret);
- return ret;
- }
- /* generate odd nonce */
- ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE);
- if (ret < 0) {
- pr_info("tpm_get_random failed (%d)\n", ret);
- return ret;
- }
- /* calculate authorization HMAC value */
- ret = TSS_authhmac(authdata, keyauth, SHA1_DIGEST_SIZE, enonce,
- nonceodd, cont, sizeof(uint32_t), &ordinal,
- keybloblen, keyblob, 0, 0);
- if (ret < 0)
- return ret;
- /* build the request buffer */
- tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_LOADKEY2);
- tpm_buf_append_u32(tb, keyhandle);
- tpm_buf_append(tb, keyblob, keybloblen);
- tpm_buf_append_u32(tb, authhandle);
- tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
- tpm_buf_append_u8(tb, cont);
- tpm_buf_append(tb, authdata, SHA1_DIGEST_SIZE);
- ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
- if (ret < 0) {
- pr_info("authhmac failed (%d)\n", ret);
- return ret;
- }
- ret = TSS_checkhmac1(tb->data, ordinal, nonceodd, keyauth,
- SHA1_DIGEST_SIZE, 0, 0);
- if (ret < 0) {
- pr_info("TSS_checkhmac1 failed (%d)\n", ret);
- return ret;
- }
- *newhandle = LOAD32(tb->data, TPM_DATA_OFFSET);
- return 0;
- }
- /*
- * Execute the FlushSpecific TPM command
- */
- static int tpm_flushspecific(struct tpm_buf *tb, uint32_t handle)
- {
- tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_FLUSHSPECIFIC);
- tpm_buf_append_u32(tb, handle);
- tpm_buf_append_u32(tb, TPM_RT_KEY);
- return trusted_tpm_send(tb->data, MAX_BUF_SIZE);
- }
- /*
- * Decrypt a blob provided by userspace using a specific key handle.
- * The handle is a well known handle or previously loaded by e.g. LoadKey2
- */
- static int tpm_unbind(struct tpm_buf *tb,
- uint32_t keyhandle, unsigned char *keyauth,
- const unsigned char *blob, uint32_t bloblen,
- void *out, uint32_t outlen)
- {
- unsigned char nonceodd[TPM_NONCE_SIZE];
- unsigned char enonce[TPM_NONCE_SIZE];
- unsigned char authdata[SHA1_DIGEST_SIZE];
- uint32_t authhandle = 0;
- unsigned char cont = 0;
- uint32_t ordinal;
- uint32_t datalen;
- int ret;
- ordinal = htonl(TPM_ORD_UNBIND);
- datalen = htonl(bloblen);
- /* session for loading the key */
- ret = oiap(tb, &authhandle, enonce);
- if (ret < 0) {
- pr_info("oiap failed (%d)\n", ret);
- return ret;
- }
- /* generate odd nonce */
- ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE);
- if (ret < 0) {
- pr_info("tpm_get_random failed (%d)\n", ret);
- return ret;
- }
- /* calculate authorization HMAC value */
- ret = TSS_authhmac(authdata, keyauth, SHA1_DIGEST_SIZE, enonce,
- nonceodd, cont, sizeof(uint32_t), &ordinal,
- sizeof(uint32_t), &datalen,
- bloblen, blob, 0, 0);
- if (ret < 0)
- return ret;
- /* build the request buffer */
- tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_UNBIND);
- tpm_buf_append_u32(tb, keyhandle);
- tpm_buf_append_u32(tb, bloblen);
- tpm_buf_append(tb, blob, bloblen);
- tpm_buf_append_u32(tb, authhandle);
- tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
- tpm_buf_append_u8(tb, cont);
- tpm_buf_append(tb, authdata, 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_checkhmac1(tb->data, ordinal, nonceodd,
- keyauth, SHA1_DIGEST_SIZE,
- sizeof(uint32_t), TPM_DATA_OFFSET,
- datalen, TPM_DATA_OFFSET + sizeof(uint32_t),
- 0, 0);
- if (ret < 0) {
- pr_info("TSS_checkhmac1 failed (%d)\n", ret);
- return ret;
- }
- memcpy(out, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t),
- min(outlen, datalen));
- return datalen;
- }
- /*
- * Sign a blob provided by userspace (that has had the hash function applied)
- * using a specific key handle. The handle is assumed to have been previously
- * loaded by e.g. LoadKey2.
- *
- * Note that the key signature scheme of the used key should be set to
- * TPM_SS_RSASSAPKCS1v15_DER. This allows the hashed input to be of any size
- * up to key_length_in_bytes - 11 and not be limited to size 20 like the
- * TPM_SS_RSASSAPKCS1v15_SHA1 signature scheme.
- */
- static int tpm_sign(struct tpm_buf *tb,
- uint32_t keyhandle, unsigned char *keyauth,
- const unsigned char *blob, uint32_t bloblen,
- void *out, uint32_t outlen)
- {
- unsigned char nonceodd[TPM_NONCE_SIZE];
- unsigned char enonce[TPM_NONCE_SIZE];
- unsigned char authdata[SHA1_DIGEST_SIZE];
- uint32_t authhandle = 0;
- unsigned char cont = 0;
- uint32_t ordinal;
- uint32_t datalen;
- int ret;
- ordinal = htonl(TPM_ORD_SIGN);
- datalen = htonl(bloblen);
- /* session for loading the key */
- ret = oiap(tb, &authhandle, enonce);
- if (ret < 0) {
- pr_info("oiap failed (%d)\n", ret);
- return ret;
- }
- /* generate odd nonce */
- ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE);
- if (ret < 0) {
- pr_info("tpm_get_random failed (%d)\n", ret);
- return ret;
- }
- /* calculate authorization HMAC value */
- ret = TSS_authhmac(authdata, keyauth, SHA1_DIGEST_SIZE, enonce,
- nonceodd, cont, sizeof(uint32_t), &ordinal,
- sizeof(uint32_t), &datalen,
- bloblen, blob, 0, 0);
- if (ret < 0)
- return ret;
- /* build the request buffer */
- tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_SIGN);
- tpm_buf_append_u32(tb, keyhandle);
- tpm_buf_append_u32(tb, bloblen);
- tpm_buf_append(tb, blob, bloblen);
- tpm_buf_append_u32(tb, authhandle);
- tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
- tpm_buf_append_u8(tb, cont);
- tpm_buf_append(tb, authdata, 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_checkhmac1(tb->data, ordinal, nonceodd,
- keyauth, SHA1_DIGEST_SIZE,
- sizeof(uint32_t), TPM_DATA_OFFSET,
- datalen, TPM_DATA_OFFSET + sizeof(uint32_t),
- 0, 0);
- if (ret < 0) {
- pr_info("TSS_checkhmac1 failed (%d)\n", ret);
- return ret;
- }
- memcpy(out, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t),
- min(datalen, outlen));
- return datalen;
- }
- /* 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)
- /*
- * Provide a part of a description of the key for /proc/keys.
- */
- static void asym_tpm_describe(const struct key *asymmetric_key,
- struct seq_file *m)
- {
- struct tpm_key *tk = asymmetric_key->payload.data[asym_crypto];
- if (!tk)
- return;
- seq_printf(m, "TPM1.2/Blob");
- }
- static void asym_tpm_destroy(void *payload0, void *payload3)
- {
- struct tpm_key *tk = payload0;
- if (!tk)
- return;
- kfree(tk->blob);
- tk->blob_len = 0;
- kfree(tk);
- }
- /* How many bytes will it take to encode the length */
- static inline uint32_t definite_length(uint32_t len)
- {
- if (len <= 127)
- return 1;
- if (len <= 255)
- return 2;
- return 3;
- }
- static inline uint8_t *encode_tag_length(uint8_t *buf, uint8_t tag,
- uint32_t 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 uint32_t derive_pub_key(const void *pub_key, uint32_t len, uint8_t *buf)
- {
- uint8_t *cur = buf;
- uint32_t n_len = definite_length(len) + 1 + len + 1;
- uint32_t e_len = definite_length(3) + 1 + 3;
- uint8_t e[3] = { 0x01, 0x00, 0x01 };
- /* SEQUENCE */
- cur = encode_tag_length(cur, 0x30, n_len + e_len);
- /* INTEGER n */
- cur = encode_tag_length(cur, 0x02, len + 1);
- cur[0] = 0x00;
- memcpy(cur + 1, pub_key, len);
- cur += len + 1;
- cur = encode_tag_length(cur, 0x02, sizeof(e));
- memcpy(cur, e, sizeof(e));
- cur += sizeof(e);
- /* Zero parameters to satisfy set_pub_key ABI. */
- memzero_explicit(cur, SETKEY_PARAMS_SIZE);
- return cur - buf;
- }
- /*
- * Determine the crypto algorithm name.
- */
- static int determine_akcipher(const char *encoding, const char *hash_algo,
- char alg_name[CRYPTO_MAX_ALG_NAME])
- {
- if (strcmp(encoding, "pkcs1") == 0) {
- if (!hash_algo) {
- strcpy(alg_name, "pkcs1pad(rsa)");
- return 0;
- }
- if (snprintf(alg_name, CRYPTO_MAX_ALG_NAME, "pkcs1pad(rsa,%s)",
- hash_algo) >= CRYPTO_MAX_ALG_NAME)
- return -EINVAL;
- return 0;
- }
- if (strcmp(encoding, "raw") == 0) {
- strcpy(alg_name, "rsa");
- return 0;
- }
- return -ENOPKG;
- }
- /*
- * Query information about a key.
- */
- static int tpm_key_query(const struct kernel_pkey_params *params,
- struct kernel_pkey_query *info)
- {
- struct tpm_key *tk = params->key->payload.data[asym_crypto];
- int ret;
- char alg_name[CRYPTO_MAX_ALG_NAME];
- struct crypto_akcipher *tfm;
- uint8_t der_pub_key[PUB_KEY_BUF_SIZE];
- uint32_t der_pub_key_len;
- int len;
- /* TPM only works on private keys, public keys still done in software */
- 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_key, tk->pub_key_len,
- der_pub_key);
- ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len);
- if (ret < 0)
- goto error_free_tfm;
- len = crypto_akcipher_maxsize(tfm);
- info->key_size = tk->key_len;
- info->max_data_size = tk->key_len / 8;
- info->max_sig_size = len;
- info->max_enc_size = len;
- info->max_dec_size = tk->key_len / 8;
- info->supported_ops = KEYCTL_SUPPORTS_ENCRYPT |
- KEYCTL_SUPPORTS_DECRYPT |
- KEYCTL_SUPPORTS_VERIFY |
- KEYCTL_SUPPORTS_SIGN;
- ret = 0;
- error_free_tfm:
- crypto_free_akcipher(tfm);
- pr_devel("<==%s() = %d\n", __func__, ret);
- return ret;
- }
- /*
- * Encryption operation is performed with the public key. Hence it is done
- * in software
- */
- static int tpm_key_encrypt(struct tpm_key *tk,
- struct kernel_pkey_params *params,
- const void *in, void *out)
- {
- char alg_name[CRYPTO_MAX_ALG_NAME];
- struct crypto_akcipher *tfm;
- struct akcipher_request *req;
- struct crypto_wait cwait;
- struct scatterlist in_sg, out_sg;
- uint8_t der_pub_key[PUB_KEY_BUF_SIZE];
- uint32_t der_pub_key_len;
- int ret;
- pr_devel("==>%s()\n", __func__);
- 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_key, tk->pub_key_len,
- der_pub_key);
- ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len);
- if (ret < 0)
- goto error_free_tfm;
- ret = -ENOMEM;
- req = akcipher_request_alloc(tfm, GFP_KERNEL);
- if (!req)
- goto error_free_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);
- ret = crypto_akcipher_encrypt(req);
- ret = crypto_wait_req(ret, &cwait);
- if (ret == 0)
- ret = req->dst_len;
- akcipher_request_free(req);
- error_free_tfm:
- crypto_free_akcipher(tfm);
- pr_devel("<==%s() = %d\n", __func__, ret);
- return ret;
- }
- /*
- * Decryption operation is performed with the private key in the TPM.
- */
- static int tpm_key_decrypt(struct tpm_key *tk,
- struct kernel_pkey_params *params,
- const void *in, void *out)
- {
- struct tpm_buf tb;
- uint32_t keyhandle;
- uint8_t srkauth[SHA1_DIGEST_SIZE];
- uint8_t keyauth[SHA1_DIGEST_SIZE];
- int r;
- pr_devel("==>%s()\n", __func__);
- if (params->hash_algo)
- return -ENOPKG;
- if (strcmp(params->encoding, "pkcs1"))
- return -ENOPKG;
- r = tpm_buf_init(&tb, 0, 0);
- if (r)
- return r;
- /* TODO: Handle a non-all zero SRK authorization */
- memset(srkauth, 0, sizeof(srkauth));
- r = tpm_loadkey2(&tb, SRKHANDLE, srkauth,
- tk->blob, tk->blob_len, &keyhandle);
- if (r < 0) {
- pr_devel("loadkey2 failed (%d)\n", r);
- goto error;
- }
- /* TODO: Handle a non-all zero key authorization */
- memset(keyauth, 0, sizeof(keyauth));
- r = tpm_unbind(&tb, keyhandle, keyauth,
- in, params->in_len, out, params->out_len);
- if (r < 0)
- pr_devel("tpm_unbind failed (%d)\n", r);
- if (tpm_flushspecific(&tb, keyhandle) < 0)
- pr_devel("flushspecific failed (%d)\n", r);
- error:
- tpm_buf_destroy(&tb);
- pr_devel("<==%s() = %d\n", __func__, r);
- return r;
- }
- /*
- * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
- */
- static const u8 digest_info_md5[] = {
- 0x30, 0x20, 0x30, 0x0c, 0x06, 0x08,
- 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* OID */
- 0x05, 0x00, 0x04, 0x10
- };
- static const u8 digest_info_sha1[] = {
- 0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
- 0x2b, 0x0e, 0x03, 0x02, 0x1a,
- 0x05, 0x00, 0x04, 0x14
- };
- static const u8 digest_info_rmd160[] = {
- 0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
- 0x2b, 0x24, 0x03, 0x02, 0x01,
- 0x05, 0x00, 0x04, 0x14
- };
- static const u8 digest_info_sha224[] = {
- 0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
- 0x05, 0x00, 0x04, 0x1c
- };
- static const u8 digest_info_sha256[] = {
- 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
- 0x05, 0x00, 0x04, 0x20
- };
- static const u8 digest_info_sha384[] = {
- 0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
- 0x05, 0x00, 0x04, 0x30
- };
- static const u8 digest_info_sha512[] = {
- 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
- 0x05, 0x00, 0x04, 0x40
- };
- static const struct asn1_template {
- const char *name;
- const u8 *data;
- size_t size;
- } asn1_templates[] = {
- #define _(X) { #X, digest_info_##X, sizeof(digest_info_##X) }
- _(md5),
- _(sha1),
- _(rmd160),
- _(sha256),
- _(sha384),
- _(sha512),
- _(sha224),
- { NULL }
- #undef _
- };
- static const struct asn1_template *lookup_asn1(const char *name)
- {
- const struct asn1_template *p;
- for (p = asn1_templates; p->name; p++)
- if (strcmp(name, p->name) == 0)
- return p;
- return NULL;
- }
- /*
- * Sign operation is performed with the private key in the TPM.
- */
- static int tpm_key_sign(struct tpm_key *tk,
- struct kernel_pkey_params *params,
- const void *in, void *out)
- {
- struct tpm_buf tb;
- uint32_t keyhandle;
- uint8_t srkauth[SHA1_DIGEST_SIZE];
- uint8_t keyauth[SHA1_DIGEST_SIZE];
- void *asn1_wrapped = NULL;
- uint32_t in_len = params->in_len;
- int r;
- pr_devel("==>%s()\n", __func__);
- if (strcmp(params->encoding, "pkcs1"))
- return -ENOPKG;
- if (params->hash_algo) {
- const struct asn1_template *asn1 =
- lookup_asn1(params->hash_algo);
- if (!asn1)
- return -ENOPKG;
- /* request enough space for the ASN.1 template + input hash */
- asn1_wrapped = kzalloc(in_len + asn1->size, GFP_KERNEL);
- if (!asn1_wrapped)
- return -ENOMEM;
- /* 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;
- }
- if (in_len > tk->key_len / 8 - 11) {
- r = -EOVERFLOW;
- goto error_free_asn1_wrapped;
- }
- r = tpm_buf_init(&tb, 0, 0);
- if (r)
- goto error_free_asn1_wrapped;
- /* TODO: Handle a non-all zero SRK authorization */
- memset(srkauth, 0, sizeof(srkauth));
- r = tpm_loadkey2(&tb, SRKHANDLE, srkauth,
- tk->blob, tk->blob_len, &keyhandle);
- if (r < 0) {
- pr_devel("loadkey2 failed (%d)\n", r);
- goto error_free_tb;
- }
- /* TODO: Handle a non-all zero key authorization */
- memset(keyauth, 0, sizeof(keyauth));
- r = tpm_sign(&tb, keyhandle, keyauth, in, in_len, out, params->out_len);
- if (r < 0)
- pr_devel("tpm_sign failed (%d)\n", r);
- if (tpm_flushspecific(&tb, keyhandle) < 0)
- pr_devel("flushspecific failed (%d)\n", r);
- error_free_tb:
- tpm_buf_destroy(&tb);
- error_free_asn1_wrapped:
- kfree(asn1_wrapped);
- pr_devel("<==%s() = %d\n", __func__, r);
- return r;
- }
- /*
- * Do encryption, decryption and signing ops.
- */
- static int tpm_key_eds_op(struct kernel_pkey_params *params,
- const void *in, void *out)
- {
- struct tpm_key *tk = params->key->payload.data[asym_crypto];
- int ret = -EOPNOTSUPP;
- /* Perform the encryption calculation. */
- switch (params->op) {
- case kernel_pkey_encrypt:
- ret = tpm_key_encrypt(tk, params, in, out);
- break;
- case kernel_pkey_decrypt:
- ret = tpm_key_decrypt(tk, params, in, out);
- break;
- case kernel_pkey_sign:
- ret = tpm_key_sign(tk, params, in, out);
- break;
- default:
- BUG();
- }
- return ret;
- }
- /*
- * Verify a signature using a public key.
- */
- static int tpm_key_verify_signature(const struct key *key,
- const struct public_key_signature *sig)
- {
- const struct tpm_key *tk = key->payload.data[asym_crypto];
- struct crypto_wait cwait;
- struct crypto_akcipher *tfm;
- struct akcipher_request *req;
- struct scatterlist src_sg[2];
- char alg_name[CRYPTO_MAX_ALG_NAME];
- uint8_t der_pub_key[PUB_KEY_BUF_SIZE];
- uint32_t der_pub_key_len;
- int ret;
- pr_devel("==>%s()\n", __func__);
- BUG_ON(!tk);
- BUG_ON(!sig);
- BUG_ON(!sig->s);
- if (!sig->digest)
- return -ENOPKG;
- ret = determine_akcipher(sig->encoding, sig->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_key, tk->pub_key_len,
- der_pub_key);
- ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len);
- if (ret < 0)
- goto error_free_tfm;
- ret = -ENOMEM;
- req = akcipher_request_alloc(tfm, GFP_KERNEL);
- if (!req)
- goto error_free_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);
- ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
- akcipher_request_free(req);
- error_free_tfm:
- crypto_free_akcipher(tfm);
- pr_devel("<==%s() = %d\n", __func__, ret);
- if (WARN_ON_ONCE(ret > 0))
- ret = -EINVAL;
- return ret;
- }
- /*
- * Parse enough information out of TPM_KEY structure:
- * TPM_STRUCT_VER -> 4 bytes
- * TPM_KEY_USAGE -> 2 bytes
- * TPM_KEY_FLAGS -> 4 bytes
- * TPM_AUTH_DATA_USAGE -> 1 byte
- * TPM_KEY_PARMS -> variable
- * UINT32 PCRInfoSize -> 4 bytes
- * BYTE* -> PCRInfoSize bytes
- * TPM_STORE_PUBKEY
- * UINT32 encDataSize;
- * BYTE* -> encDataSize;
- *
- * TPM_KEY_PARMS:
- * TPM_ALGORITHM_ID -> 4 bytes
- * TPM_ENC_SCHEME -> 2 bytes
- * TPM_SIG_SCHEME -> 2 bytes
- * UINT32 parmSize -> 4 bytes
- * BYTE* -> variable
- */
- static int extract_key_parameters(struct tpm_key *tk)
- {
- const void *cur = tk->blob;
- uint32_t len = tk->blob_len;
- const void *pub_key;
- uint32_t sz;
- uint32_t key_len;
- if (len < 11)
- return -EBADMSG;
- /* Ensure this is a legacy key */
- if (get_unaligned_be16(cur + 4) != 0x0015)
- return -EBADMSG;
- /* Skip to TPM_KEY_PARMS */
- cur += 11;
- len -= 11;
- if (len < 12)
- return -EBADMSG;
- /* Make sure this is an RSA key */
- if (get_unaligned_be32(cur) != 0x00000001)
- return -EBADMSG;
- /* Make sure this is TPM_ES_RSAESPKCSv15 encoding scheme */
- if (get_unaligned_be16(cur + 4) != 0x0002)
- return -EBADMSG;
- /* Make sure this is TPM_SS_RSASSAPKCS1v15_DER signature scheme */
- if (get_unaligned_be16(cur + 6) != 0x0003)
- return -EBADMSG;
- sz = get_unaligned_be32(cur + 8);
- if (len < sz + 12)
- return -EBADMSG;
- /* Move to TPM_RSA_KEY_PARMS */
- len -= 12;
- cur += 12;
- /* Grab the RSA key length */
- key_len = get_unaligned_be32(cur);
- switch (key_len) {
- case 512:
- case 1024:
- case 1536:
- case 2048:
- break;
- default:
- return -EINVAL;
- }
- /* Move just past TPM_KEY_PARMS */
- cur += sz;
- len -= sz;
- if (len < 4)
- return -EBADMSG;
- sz = get_unaligned_be32(cur);
- if (len < 4 + sz)
- return -EBADMSG;
- /* Move to TPM_STORE_PUBKEY */
- cur += 4 + sz;
- len -= 4 + sz;
- /* Grab the size of the public key, it should jive with the key size */
- sz = get_unaligned_be32(cur);
- if (sz > 256)
- return -EINVAL;
- pub_key = cur + 4;
- tk->key_len = key_len;
- tk->pub_key = pub_key;
- tk->pub_key_len = sz;
- return 0;
- }
- /* Given the blob, parse it and load it into the TPM */
- struct tpm_key *tpm_key_create(const void *blob, uint32_t blob_len)
- {
- int r;
- struct tpm_key *tk;
- r = tpm_is_tpm2(NULL);
- if (r < 0)
- goto error;
- /* We don't support TPM2 yet */
- if (r > 0) {
- r = -ENODEV;
- goto error;
- }
- r = -ENOMEM;
- tk = kzalloc(sizeof(struct tpm_key), GFP_KERNEL);
- if (!tk)
- goto error;
- tk->blob = kmemdup(blob, blob_len, GFP_KERNEL);
- if (!tk->blob)
- goto error_memdup;
- tk->blob_len = blob_len;
- r = extract_key_parameters(tk);
- if (r < 0)
- goto error_extract;
- return tk;
- error_extract:
- kfree(tk->blob);
- tk->blob_len = 0;
- error_memdup:
- kfree(tk);
- error:
- return ERR_PTR(r);
- }
- EXPORT_SYMBOL_GPL(tpm_key_create);
- /*
- * TPM-based asymmetric key subtype
- */
- struct asymmetric_key_subtype asym_tpm_subtype = {
- .owner = THIS_MODULE,
- .name = "asym_tpm",
- .name_len = sizeof("asym_tpm") - 1,
- .describe = asym_tpm_describe,
- .destroy = asym_tpm_destroy,
- .query = tpm_key_query,
- .eds_op = tpm_key_eds_op,
- .verify_signature = tpm_key_verify_signature,
- };
- EXPORT_SYMBOL_GPL(asym_tpm_subtype);
- MODULE_DESCRIPTION("TPM based asymmetric key subtype");
- MODULE_AUTHOR("Intel Corporation");
- MODULE_LICENSE("GPL v2");
|