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KEYS: trusted: Fix incorrect handling of tpm_get_random()

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When tpm_get_random() was introduced, it defined the following API for the
return value:

1. A positive value tells how many bytes of random data was generated.
2. A negative value on error.

However, in the call sites the API was used incorrectly, i.e. as it would
only return negative values and otherwise zero. Returning he positive read
counts to the user space does not make any possible sense.

Fix this by returning -EIO when tpm_get_random() returns a positive value.

Fixes: 41ab999c80 ("tpm: Move tpm_get_random api into the TPM device driver")
Cc: stable@vger.kernel.org
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Kent Yoder <key@linux.vnet.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
This commit is contained in:
Jarkko Sakkinen 2021-01-29 01:56:19 +02:00
parent 90cba8d20f
commit 5df16caada
1 changed files with 17 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
security/keys/trusted-keys/trusted_tpm1.c
View File

@ -403,9 +403,12 @@ static int osap(struct tpm_buf *tb, struct osapsess *s,
int ret;
ret = tpm_get_random(chip, ononce, TPM_NONCE_SIZE);
if (ret != 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);
@ -496,8 +499,12 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
goto out;
ret = tpm_get_random(chip, td->nonceodd, TPM_NONCE_SIZE);
if (ret < 0)
return ret;
if (ret != TPM_NONCE_SIZE)
goto out;
return -EIO;
ordinal = htonl(TPM_ORD_SEAL);
datsize = htonl(datalen);
pcrsize = htonl(pcrinfosize);
@ -601,9 +608,12 @@ static int tpm_unseal(struct tpm_buf *tb,
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("trusted_key: tpm_get_random failed (%d)\n", ret);
return ret;
return -EIO;
}
ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE,
enonce1, nonceodd, cont, sizeof(uint32_t),
@ -1013,8 +1023,12 @@ static int trusted_instantiate(struct key *key,
case Opt_new:
key_len = payload->key_len;
ret = tpm_get_random(chip, payload->key, key_len);
if (ret < 0)
goto out;
if (ret != key_len) {
pr_info("trusted_key: key_create failed (%d)\n", ret);
ret = -EIO;
goto out;
}
if (tpm2)