@@ -30,6 +30,7 @@ struct trusted_key_options {
uint16_t keytype;
uint32_t keyhandle;
unsigned char keyauth[TPM_DIGEST_SIZE];
+ uint32_t blobauth_len;
unsigned char blobauth[TPM_DIGEST_SIZE];
uint32_t pcrinfo_len;
unsigned char pcrinfo[MAX_PCRINFO_SIZE];
@@ -781,13 +781,34 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
return -EINVAL;
break;
case Opt_blobauth:
- if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
- return -EINVAL;
- res = hex2bin(opt->blobauth, args[0].from,
- SHA1_DIGEST_SIZE);
- if (res < 0)
- return -EINVAL;
+ /*
+ * 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;
+ return 0;
+ }
+
+ if (tpm2 &&
+ opt->blobauth_len <= sizeof(opt->blobauth)) {
+ memcpy(opt->blobauth, args[0].from,
+ opt->blobauth_len);
+ return 0;
+ }
+
+ return -EINVAL;
+
break;
+
case Opt_migratable:
if (*args[0].from == '0')
pay->migratable = 0;
@@ -91,10 +91,13 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
TPM_DIGEST_SIZE);
/* sensitive */
- tpm_buf_append_u16(&buf, 4 + TPM_DIGEST_SIZE + payload->key_len + 1);
+ tpm_buf_append_u16(&buf, 4 + options->blobauth_len +
+ payload->key_len + 1);
+
+ tpm_buf_append_u16(&buf, options->blobauth_len);
+ if (options->blobauth_len)
+ tpm_buf_append(&buf, options->blobauth, options->blobauth_len);
- tpm_buf_append_u16(&buf, TPM_DIGEST_SIZE);
- tpm_buf_append(&buf, options->blobauth, TPM_DIGEST_SIZE);
tpm_buf_append_u16(&buf, payload->key_len + 1);
tpm_buf_append(&buf, payload->key, payload->key_len);
tpm_buf_append_u8(&buf, payload->migratable);
@@ -258,7 +261,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
NULL /* nonce */, 0,
TPM2_SA_CONTINUE_SESSION,
options->blobauth /* hmac */,
- TPM_DIGEST_SIZE);
+ options->blobauth_len);
rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
if (rc > 0)
In TPM 1.2 an authorization was a 20 byte number. The spec actually recommended you to hash variable length passwords and use the sha1 hash as the authorization. Because the spec doesn't require this hashing, the current authorization for trusted keys is a 40 digit hex number. For TPM 2.0 the spec allows the passing in of variable length passwords and passphrases directly, so we should allow that in trusted keys for ease of use. Update the 'blobauth' parameter to take this into account, so we can now use plain text passwords for the keys. so before keyctl add trusted kmk "new 32 blobauth=f572d396fae9206628714fb2ce00f72e94f2258f keyhandle=81000001" @u after we will accept both the old hex sha1 form as well as a new directly supplied password: keyctl add trusted kmk "new 32 blobauth=hello keyhandle=81000001" @u Since a sha1 hex code must be exactly 40 bytes long and a direct password must be 20 or less, we use the length as the discriminator for which form is input. Note this is both and enhancement and a potential bug fix. The TPM 2.0 spec requires us to strip leading zeros, meaning empyty authorization is a zero length HMAC whereas we're currently passing in 20 bytes of zeros. A lot of TPMs simply accept this as OK, but the Microsoft TPM emulator rejects it with TPM_RC_BAD_AUTH, so this patch makes the Microsoft TPM emulator work with trusted keys. Fixes: 0fe5480303a1 ("keys, trusted: seal/unseal with TPM 2.0 chips") Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> --- v6: change comment, eliminate else clauses and add fixes tag v7: fixes before signoff v10: wrap some lines --- include/keys/trusted-type.h | 1 + security/keys/trusted-keys/trusted_tpm1.c | 33 ++++++++++++++++++----- security/keys/trusted-keys/trusted_tpm2.c | 11 +++++--- 3 files changed, 35 insertions(+), 10 deletions(-)