KEYS: asym_tpm: Implement tpm_sign [ver #2]
Signed-off-by: Denis Kenzior <denkenz@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: James Morris <james.morris@microsoft.com>
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@ -20,9 +20,11 @@
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#define TPM_ORD_FLUSHSPECIFIC 186
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#define TPM_ORD_FLUSHSPECIFIC 186
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#define TPM_ORD_LOADKEY2 65
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#define TPM_ORD_LOADKEY2 65
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#define TPM_ORD_UNBIND 30
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#define TPM_ORD_UNBIND 30
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#define TPM_ORD_SIGN 60
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#define TPM_LOADKEY2_SIZE 59
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#define TPM_LOADKEY2_SIZE 59
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#define TPM_FLUSHSPECIFIC_SIZE 18
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#define TPM_FLUSHSPECIFIC_SIZE 18
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#define TPM_UNBIND_SIZE 63
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#define TPM_UNBIND_SIZE 63
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#define TPM_SIGN_SIZE 63
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#define TPM_RT_KEY 0x00000001
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#define TPM_RT_KEY 0x00000001
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@ -189,6 +191,91 @@ static int tpm_unbind(struct tpm_buf *tb,
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return datalen;
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return datalen;
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}
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}
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/*
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* Sign a blob provided by userspace (that has had the hash function applied)
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* using a specific key handle. The handle is assumed to have been previously
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* loaded by e.g. LoadKey2.
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*
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* Note that the key signature scheme of the used key should be set to
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* TPM_SS_RSASSAPKCS1v15_DER. This allows the hashed input to be of any size
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* up to key_length_in_bytes - 11 and not be limited to size 20 like the
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* TPM_SS_RSASSAPKCS1v15_SHA1 signature scheme.
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*/
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static int tpm_sign(struct tpm_buf *tb,
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uint32_t keyhandle, unsigned char *keyauth,
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const unsigned char *blob, uint32_t bloblen,
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void *out, uint32_t outlen)
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{
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unsigned char nonceodd[TPM_NONCE_SIZE];
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unsigned char enonce[TPM_NONCE_SIZE];
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unsigned char authdata[SHA1_DIGEST_SIZE];
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uint32_t authhandle = 0;
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unsigned char cont = 0;
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uint32_t ordinal;
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uint32_t datalen;
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int ret;
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ordinal = htonl(TPM_ORD_SIGN);
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datalen = htonl(bloblen);
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/* session for loading the key */
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ret = oiap(tb, &authhandle, enonce);
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if (ret < 0) {
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pr_info("oiap failed (%d)\n", ret);
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return ret;
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}
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/* generate odd nonce */
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ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE);
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if (ret < 0) {
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pr_info("tpm_get_random failed (%d)\n", ret);
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return ret;
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}
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/* calculate authorization HMAC value */
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ret = TSS_authhmac(authdata, keyauth, SHA1_DIGEST_SIZE, enonce,
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nonceodd, cont, sizeof(uint32_t), &ordinal,
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sizeof(uint32_t), &datalen,
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bloblen, blob, 0, 0);
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if (ret < 0)
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return ret;
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/* build the request buffer */
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INIT_BUF(tb);
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store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
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store32(tb, TPM_SIGN_SIZE + bloblen);
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store32(tb, TPM_ORD_SIGN);
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store32(tb, keyhandle);
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store32(tb, bloblen);
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storebytes(tb, blob, bloblen);
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store32(tb, authhandle);
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storebytes(tb, nonceodd, TPM_NONCE_SIZE);
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store8(tb, cont);
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storebytes(tb, authdata, SHA1_DIGEST_SIZE);
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ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
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if (ret < 0) {
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pr_info("authhmac failed (%d)\n", ret);
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return ret;
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}
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datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
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ret = TSS_checkhmac1(tb->data, ordinal, nonceodd,
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keyauth, SHA1_DIGEST_SIZE,
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sizeof(uint32_t), TPM_DATA_OFFSET,
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datalen, TPM_DATA_OFFSET + sizeof(uint32_t),
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0, 0);
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if (ret < 0) {
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pr_info("TSS_checkhmac1 failed (%d)\n", ret);
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return ret;
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}
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memcpy(out, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t),
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min(datalen, outlen));
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return datalen;
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}
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/*
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/*
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* Maximum buffer size for the BER/DER encoded public key. The public key
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* Maximum buffer size for the BER/DER encoded public key. The public key
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* is of the form SEQUENCE { INTEGER n, INTEGER e } where n is a maximum 2048
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* is of the form SEQUENCE { INTEGER n, INTEGER e } where n is a maximum 2048
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