From: Jarkko Sakkinen <jarkko@kernel.org>
To: linux-integrity@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Jarkko Sakkinen <jarkko@kernel.org>,
James Bottomley <James.Bottomley@HansenPartnership.com>,
William Roberts <bill.c.roberts@gmail.com>,
Stefan Berger <stefanb@linux.ibm.com>,
David Howells <dhowells@redhat.com>,
Jason Gunthorpe <jgg@ziepe.ca>, Mimi Zohar <zohar@linux.ibm.com>,
Mario Limonciello <mario.limonciello@amd.com>,
Jerry Snitselaar <jsnitsel@redhat.com>,
Peter Huewe <peterhuewe@gmx.de>,
James Bottomley <jejb@linux.ibm.com>,
Paul Moore <paul@paul-moore.com>,
James Morris <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
Julien Gomes <julien@arista.com>
Subject: [PATCH v4 8/8] KEYS: trusted: tpm2: Use struct tpm_buf for sized buffers
Date: Tue, 21 Nov 2023 23:17:17 +0200 [thread overview]
Message-ID: <20231121211717.31681-9-jarkko@kernel.org> (raw)
In-Reply-To: <20231121211717.31681-1-jarkko@kernel.org>
Take advantage of the new sized buffer (TPM2B) mode of struct tpm_buf in
tpm2_seal_trusted(). This allows to add robustness to the command
construction without requiring to calculate buffer sizes manually.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v3 [2023-11-21]: A boundary error check as response for the feeedback
from Mario Limenciello:
https://lore.kernel.org/linux-integrity/3f9086f6-935f-48a7-889b-c71398422fa1@amd.com/
v2: Use tpm_buf_read_*
---
security/keys/trusted-keys/trusted_tpm2.c | 54 +++++++++++++----------
1 file changed, 31 insertions(+), 23 deletions(-)
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index bc700f85f80b..97b1dfca2dba 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -228,8 +228,9 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
struct trusted_key_payload *payload,
struct trusted_key_options *options)
{
+ off_t offset = TPM_HEADER_SIZE;
+ struct tpm_buf buf, sized;
int blob_len = 0;
- struct tpm_buf buf;
u32 hash;
u32 flags;
int i;
@@ -258,6 +259,14 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
return rc;
}
+ rc = tpm_buf_init_sized(&sized);
+ if (rc) {
+ tpm_buf_destroy(&buf);
+ tpm_put_ops(chip);
+ return rc;
+ }
+
+ tpm_buf_reset(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
tpm_buf_append_u32(&buf, options->keyhandle);
tpm2_buf_append_auth(&buf, TPM2_RS_PW,
NULL /* nonce */, 0,
@@ -266,36 +275,36 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
TPM_DIGEST_SIZE);
/* sensitive */
- tpm_buf_append_u16(&buf, 4 + options->blobauth_len + payload->key_len);
+ tpm_buf_append_u16(&sized, options->blobauth_len);
- tpm_buf_append_u16(&buf, options->blobauth_len);
if (options->blobauth_len)
- tpm_buf_append(&buf, options->blobauth, options->blobauth_len);
+ tpm_buf_append(&sized, options->blobauth, options->blobauth_len);
- tpm_buf_append_u16(&buf, payload->key_len);
- tpm_buf_append(&buf, payload->key, payload->key_len);
+ tpm_buf_append_u16(&sized, payload->key_len);
+ tpm_buf_append(&sized, payload->key, payload->key_len);
+ tpm_buf_append(&buf, sized.data, sized.length);
/* public */
- tpm_buf_append_u16(&buf, 14 + options->policydigest_len);
- tpm_buf_append_u16(&buf, TPM_ALG_KEYEDHASH);
- tpm_buf_append_u16(&buf, hash);
+ tpm_buf_reset_sized(&sized);
+ tpm_buf_append_u16(&sized, TPM_ALG_KEYEDHASH);
+ tpm_buf_append_u16(&sized, hash);
/* key properties */
flags = 0;
flags |= options->policydigest_len ? 0 : TPM2_OA_USER_WITH_AUTH;
- flags |= payload->migratable ? 0 : (TPM2_OA_FIXED_TPM |
- TPM2_OA_FIXED_PARENT);
- tpm_buf_append_u32(&buf, flags);
+ flags |= payload->migratable ? 0 : (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT);
+ tpm_buf_append_u32(&sized, flags);
/* policy */
- tpm_buf_append_u16(&buf, options->policydigest_len);
+ tpm_buf_append_u16(&sized, options->policydigest_len);
if (options->policydigest_len)
- tpm_buf_append(&buf, options->policydigest,
- options->policydigest_len);
+ tpm_buf_append(&sized, options->policydigest, options->policydigest_len);
/* public parameters */
- tpm_buf_append_u16(&buf, TPM_ALG_NULL);
- tpm_buf_append_u16(&buf, 0);
+ tpm_buf_append_u16(&sized, TPM_ALG_NULL);
+ tpm_buf_append_u16(&sized, 0);
+
+ tpm_buf_append(&buf, sized.data, sized.length);
/* outside info */
tpm_buf_append_u16(&buf, 0);
@@ -312,21 +321,20 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
if (rc)
goto out;
- blob_len = be32_to_cpup((__be32 *) &buf.data[TPM_HEADER_SIZE]);
- if (blob_len > MAX_BLOB_SIZE) {
+ blob_len = tpm_buf_read_u32(&buf, &offset);
+ if (blob_len > MAX_BLOB_SIZE || buf.flags & TPM_BUF_BOUNDARY_ERROR) {
rc = -E2BIG;
goto out;
}
- if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 4 + blob_len) {
+ if (buf.length - offset < blob_len) {
rc = -EFAULT;
goto out;
}
- blob_len = tpm2_key_encode(payload, options,
- &buf.data[TPM_HEADER_SIZE + 4],
- blob_len);
+ blob_len = tpm2_key_encode(payload, options, &buf.data[offset], blob_len);
out:
+ tpm_buf_destroy(&sized);
tpm_buf_destroy(&buf);
if (rc > 0) {
--
2.42.1
prev parent reply other threads:[~2023-11-21 21:17 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-21 21:17 [PATCH v4 0/8] Extend struct tpm_buf to support sized buffers (TPM2B) Jarkko Sakkinen
2023-11-21 21:17 ` [PATCH v4 1/8] tpm: Remove unused tpm_buf_tag() Jarkko Sakkinen
2023-11-21 21:17 ` [PATCH v4 2/8] tpm: Remove tpm_send() Jarkko Sakkinen
2023-11-21 21:17 ` [PATCH v4 3/8] tpm: Move buffer handling from static inlines to real functions Jarkko Sakkinen
2023-11-21 21:17 ` [PATCH v4 4/8] tpm: Update &tpm_buf documentation Jarkko Sakkinen
2023-11-21 21:17 ` [PATCH v4 5/8] tpm: Store the length of the tpm_buf data separately Jarkko Sakkinen
2023-11-21 21:17 ` [PATCH v4 6/8] tpm: TPM2B formatted buffers Jarkko Sakkinen
2023-11-21 21:17 ` [PATCH v4 7/8] tpm: Add tpm_buf_read_{u8,u16,u32} Jarkko Sakkinen
2023-11-21 21:17 ` Jarkko Sakkinen [this message]
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