diff options
| -rw-r--r-- | crypto/asymmetric_keys/asym_tpm.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/crypto/asymmetric_keys/asym_tpm.c b/crypto/asymmetric_keys/asym_tpm.c index 6a2d33014ecc..e893b5212222 100644 --- a/crypto/asymmetric_keys/asym_tpm.c +++ b/crypto/asymmetric_keys/asym_tpm.c @@ -18,8 +18,10 @@ #define TPM_ORD_FLUSHSPECIFIC 186 #define TPM_ORD_LOADKEY2 65 +#define TPM_ORD_UNBIND 30 #define TPM_LOADKEY2_SIZE 59 #define TPM_FLUSHSPECIFIC_SIZE 18 +#define TPM_UNBIND_SIZE 63 #define TPM_RT_KEY 0x00000001 @@ -107,6 +109,86 @@ static int tpm_flushspecific(struct tpm_buf *tb, uint32_t handle) } /* + * 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 */ + INIT_BUF(tb); + store16(tb, TPM_TAG_RQU_AUTH1_COMMAND); + store32(tb, TPM_UNBIND_SIZE + bloblen); + store32(tb, TPM_ORD_UNBIND); + store32(tb, keyhandle); + store32(tb, bloblen); + storebytes(tb, blob, bloblen); + store32(tb, authhandle); + storebytes(tb, nonceodd, TPM_NONCE_SIZE); + store8(tb, cont); + storebytes(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; +} + +/* * 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 |