All of lore.kernel.org
 help / color / mirror / Atom feed
From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: linux-integrity@vger.kernel.org
Cc: Jarkko Sakkinen <jarkko@kernel.org>,
	keyrings@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH 08/12] tpm: add hmac checks to tpm2_pcr_extend()
Date: Thu, 16 Feb 2023 15:14:06 -0500	[thread overview]
Message-ID: <20230216201410.15010-9-James.Bottomley@HansenPartnership.com> (raw)
In-Reply-To: <20230216201410.15010-1-James.Bottomley@HansenPartnership.com>

We use tpm2_pcr_extend() in trusted keys to extend a PCR to prevent a
key from being re-loaded until the next reboot.  To use this
functionality securely, that extend must be protected by a session
hmac.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---
 drivers/char/tpm/tpm2-cmd.c | 27 ++++++++++-----------------
 1 file changed, 10 insertions(+), 17 deletions(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 056dad3dd5c9..ef038cc71f9c 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -216,13 +216,6 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 	return rc;
 }
 
-struct tpm2_null_auth_area {
-	__be32  handle;
-	__be16  nonce_size;
-	u8  attributes;
-	__be16  auth_size;
-} __packed;
-
 /**
  * tpm2_pcr_extend() - extend a PCR value
  *
@@ -236,24 +229,22 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 		    struct tpm_digest *digests)
 {
 	struct tpm_buf buf;
-	struct tpm2_null_auth_area auth_area;
 	int rc;
 	int i;
 
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
+	rc = tpm2_start_auth_session(chip);
 	if (rc)
 		return rc;
 
-	tpm_buf_append_u32(&buf, pcr_idx);
+	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
+	if (rc) {
+		tpm2_end_auth_session(chip);
+		return rc;
+	}
 
-	auth_area.handle = cpu_to_be32(TPM2_RS_PW);
-	auth_area.nonce_size = 0;
-	auth_area.attributes = 0;
-	auth_area.auth_size = 0;
+	tpm_buf_append_name(chip, &buf, pcr_idx, NULL);
+	tpm_buf_append_hmac_session(chip, &buf, 0, NULL, 0);
 
-	tpm_buf_append_u32(&buf, sizeof(struct tpm2_null_auth_area));
-	tpm_buf_append(&buf, (const unsigned char *)&auth_area,
-		       sizeof(auth_area));
 	tpm_buf_append_u32(&buf, chip->nr_allocated_banks);
 
 	for (i = 0; i < chip->nr_allocated_banks; i++) {
@@ -262,7 +253,9 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 			       chip->allocated_banks[i].digest_size);
 	}
 
+	tpm_buf_fill_hmac_session(chip, &buf);
 	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting extend a PCR value");
+	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
 
 	tpm_buf_destroy(&buf);
 
-- 
2.35.3


  parent reply	other threads:[~2023-02-16 20:18 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-16 20:13 [PATCH 00/12] add integrity and security to TPM2 transactions James Bottomley
2023-02-16 20:13 ` [PATCH 01/12] crypto: lib - implement library version of AES in CFB mode James Bottomley
2023-02-27  7:47   ` Jarkko Sakkinen
2023-02-16 20:14 ` [PATCH 02/12] tpm: move buffer handling from static inlines to real functions James Bottomley
2023-02-27  8:18   ` Jarkko Sakkinen
2023-02-16 20:14 ` [PATCH 03/12] tpm: add buffer handling for TPM2B types James Bottomley
2023-02-27  8:31   ` Jarkko Sakkinen
2023-03-28 19:42     ` James Bottomley
2023-02-16 20:14 ` [PATCH 04/12] tpm: add cursor based buffer functions for response parsing James Bottomley
2023-02-27  8:34   ` Jarkko Sakkinen
2023-02-16 20:14 ` [PATCH 05/12] tpm: add buffer function to point to returned parameters James Bottomley
2023-02-27  8:36   ` Jarkko Sakkinen
2023-02-16 20:14 ` [PATCH 06/12] tpm: export the context save and load commands James Bottomley
2023-02-27  8:37   ` Jarkko Sakkinen
2023-04-03 16:54     ` James Bottomley
2023-02-16 20:14 ` [PATCH 07/12] tpm: Add full HMAC and encrypt/decrypt session handling code James Bottomley
2023-02-16 23:37   ` kernel test robot
2023-02-17 11:30   ` kernel test robot
2023-02-17 14:22     ` James Bottomley
2023-02-17 14:23       ` Ard Biesheuvel
2023-02-16 20:14 ` James Bottomley [this message]
2023-02-27  9:16   ` [PATCH 08/12] tpm: add hmac checks to tpm2_pcr_extend() Jarkko Sakkinen
2023-02-16 20:14 ` [PATCH 09/12] tpm: add session encryption protection to tpm2_get_random() James Bottomley
2023-02-16 20:14 ` [PATCH 10/12] KEYS: trusted: Add session encryption protection to the seal/unseal path James Bottomley
2023-02-16 20:40 ` [PATCH 11/12] tpm: add the null key name as a sysfs export James Bottomley
2023-02-17 10:59   ` kernel test robot
2023-02-16 20:41 ` [PATCH 12/12] Documentation: add tpm-security.rst James Bottomley
2023-02-17 22:43 ` [PATCH 00/12] add integrity and security to TPM2 transactions Jarkko Sakkinen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20230216201410.15010-9-James.Bottomley@HansenPartnership.com \
    --to=james.bottomley@hansenpartnership.com \
    --cc=ardb@kernel.org \
    --cc=jarkko@kernel.org \
    --cc=keyrings@vger.kernel.org \
    --cc=linux-integrity@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.