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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: linux-integrity@vger.kernel.org
Cc: linux-security-module@vger.kernel.org,
	James Bottomley <James.Bottomley@HansenPartnership.com>,
	Tomas Winkler <tomas.winkler@intel.com>,
	Tadeusz Struk <tadeusz.struk@intel.com>,
	Stefan Berger <stefanb@linux.vnet.ibm.com>,
	Nayna Jain <nayna@linux.ibm.com>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	stable@vger.kernel.org, Peter Huewe <peterhuewe@gmx.de>,
	Jason Gunthorpe <jgg@ziepe.ca>, Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v6 04/17] tpm: call tpm2_flush_space() on error in tpm_try_transmit()
Date: Tue, 13 Nov 2018 14:25:53 +0200	[thread overview]
Message-ID: <20181113122609.21643-5-jarkko.sakkinen@linux.intel.com> (raw)
In-Reply-To: <20181113122609.21643-1-jarkko.sakkinen@linux.intel.com>

Always call tpm2_flush_space() on failure in tpm_try_transmit() so that
the volatile memory of the TPM gets cleared. If /dev/tpm0 does not have
sufficient permissions (usually it has), this could lead to the leakage
of TPM objects. Through /dev/tpmrm0 this issue does not raise any new
security concerns.

Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: stable@vger.kernel.org
Fixes: 745b361e989a ("tpm:tpm: infrastructure for TPM spaces")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
---
 drivers/char/tpm/tpm-interface.c | 33 +++++++++++++++-----------------
 drivers/char/tpm/tpm.h           |  1 +
 drivers/char/tpm/tpm2-space.c    |  2 +-
 3 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 64510ed81b46..c9efd1b9fd2c 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -224,14 +224,14 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 
 	rc = tpm2_prepare_space(chip, space, ordinal, buf);
 	if (rc)
-		goto out;
+		goto out_idle;
 
 	rc = chip->ops->send(chip, buf, count);
 	if (rc < 0) {
 		if (rc != -EPIPE)
 			dev_err(&chip->dev,
 				"%s: tpm_send: error %d\n", __func__, rc);
-		goto out;
+		goto out_space;
 	}
 
 	if (chip->flags & TPM_CHIP_FLAG_IRQ)
@@ -247,7 +247,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 		if (chip->ops->req_canceled(chip, status)) {
 			dev_err(&chip->dev, "Operation Canceled\n");
 			rc = -ECANCELED;
-			goto out;
+			goto out_space;
 		}
 
 		tpm_msleep(TPM_TIMEOUT_POLL);
@@ -257,30 +257,27 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 	chip->ops->cancel(chip);
 	dev_err(&chip->dev, "Operation Timed out\n");
 	rc = -ETIME;
-	goto out;
+	goto out_space;
 
 out_recv:
 	len = chip->ops->recv(chip, buf, bufsiz);
 	if (len < 0) {
 		rc = len;
-		dev_err(&chip->dev,
-			"tpm_transmit: tpm_recv: error %d\n", rc);
-		goto out;
-	} else if (len < TPM_HEADER_SIZE) {
+		dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc);
+	} else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length))
 		rc = -EFAULT;
-		goto out;
-	}
 
-	if (len != be32_to_cpu(header->length)) {
-		rc = -EFAULT;
-		goto out;
+out_space:
+	if (rc) {
+		tpm2_flush_space(chip);
+	} else {
+		rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
+		if (rc)
+			dev_err(&chip->dev, "tpm2_commit_space: error %d\n",
+				rc);
 	}
 
-	rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
-	if (rc)
-		dev_err(&chip->dev, "tpm2_commit_space: error %d\n", rc);
-
-out:
+out_idle:
 	/* may fail but do not override previous error value in rc */
 	tpm_go_idle(chip, flags);
 
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 49bca4d1e786..229ac42b644e 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -579,6 +579,7 @@ int tpm2_probe(struct tpm_chip *chip);
 int tpm2_find_cc(struct tpm_chip *chip, u32 cc);
 int tpm2_init_space(struct tpm_space *space);
 void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space);
+void tpm2_flush_space(struct tpm_chip *chip);
 int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
 		       u8 *cmd);
 int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 1131a8e7b79b..d53c882268ff 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -162,7 +162,7 @@ static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
 	return 0;
 }
 
-static void tpm2_flush_space(struct tpm_chip *chip)
+void tpm2_flush_space(struct tpm_chip *chip)
 {
 	struct tpm_space *space = &chip->work_space;
 	int i;
-- 
2.19.1


  parent reply	other threads:[~2018-11-13 12:26 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-13 12:25 [PATCH v6 00/17] Removed nested TPM operations Jarkko Sakkinen
2018-11-13 12:25 ` [PATCH v6 01/17] tpm: use tpm_buf in tpm_transmit_cmd() as the IO parameter Jarkko Sakkinen
2018-11-13 12:25 ` [PATCH v6 02/17] tpm: fix invalid return value in pubek_show() Jarkko Sakkinen
2018-11-13 12:25 ` [PATCH v6 03/17] tpm: return 0 from pcrs_show() when tpm1_pcr_read() fails Jarkko Sakkinen
2018-11-13 12:25 ` Jarkko Sakkinen [this message]
2018-11-13 12:25 ` [PATCH v6 05/17] tpm: print tpm2_commit_space() error inside tpm2_commit_space() Jarkko Sakkinen
2018-11-13 12:25 ` [PATCH v6 06/17] tpm: clean up tpm_try_transmit() error handling flow Jarkko Sakkinen
2018-11-13 12:25 ` [PATCH v6 07/17] tpm: declare struct tpm_header Jarkko Sakkinen
2018-11-13 12:25 ` [PATCH v6 08/17] tpm: access command header through struct in tpm_try_transmit() Jarkko Sakkinen
2018-11-13 12:25 ` [PATCH v6 09/17] tpm: move tpm_validate_commmand() to tpm2-space.c Jarkko Sakkinen
2018-11-13 12:25 ` [PATCH v6 10/17] tpm: encapsulate tpm_dev_transmit() Jarkko Sakkinen
2018-11-13 12:26 ` [PATCH v6 11/17] tpm: move TPM space code out of tpm_transmit() Jarkko Sakkinen
2018-11-13 12:26 ` [PATCH v6 12/17] tpm: remove @space from tpm_transmit() Jarkko Sakkinen
2018-11-13 12:26 ` [PATCH v6 13/17] tpm: use tpm_try_get_ops() in tpm-sysfs.c Jarkko Sakkinen
2018-11-13 12:26 ` [PATCH v6 14/17] tpm: remove TPM_TRANSMIT_UNLOCKED flag Jarkko Sakkinen
2018-11-13 12:26 ` [PATCH v6 15/17] tpm: introduce tpm_chip_start() and tpm_chip_stop() Jarkko Sakkinen
2018-11-13 12:26 ` [PATCH v6 16/17] tpm: take TPM chip power gating out of tpm_transmit() Jarkko Sakkinen
2018-11-13 12:26 ` [PATCH v6 17/17] tpm: remove @flags from tpm_transmit() Jarkko Sakkinen
2018-11-13 12:30 ` [PATCH v6 00/17] Removed nested TPM operations Winkler, Tomas
2018-11-13 16:55   ` Jarkko Sakkinen

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