linux-kernel - [PATCH 3.2 36/74] tpm: fix a kernel memory leak in tpm-sysfs.c

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Message-ID: <lsq.1507552234.373365865@decadent.org.uk>
Date:   Mon, 09 Oct 2017 13:30:34 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "James Morris" <james.l.morris@...cle.com>,
        "Stefan Berger" <stefanb@...ux.vnet.ibm.com>,
        "Jarkko Sakkinen" <jarkko.sakkinen@...ux.intel.com>,
        "Jason Gunthorpe" <jgunthorpe@...idianresearch.com>
Subject: [PATCH 3.2 36/74] tpm: fix a kernel memory leak in tpm-sysfs.c

3.2.94-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>

commit 13b47cfcfc60495cde216eef4c01040d76174cbe upstream.

While cleaning up sysfs callback that prints EK we discovered a kernel
memory leak. This commit fixes the issue by zeroing the buffer used for
TPM command/response.

The leak happen when we use either tpm_vtpm_proxy, tpm_ibmvtpm or
xen-tpmfront.

Fixes: 0883743825e3 ("TPM: sysfs functions consolidation")
Reported-by: Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Tested-by: Stefan Berger <stefanb@...ux.vnet.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Signed-off-by: James Morris <james.l.morris@...cle.com>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/char/tpm/tpm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -879,9 +879,10 @@ ssize_t tpm_show_pubek(struct device *de
 	ssize_t err;
 	int i, rc;
 	char *str = buf;
-
 	struct tpm_chip *chip = dev_get_drvdata(dev);
 
+	memset(&tpm_cmd, 0, sizeof(tpm_cmd));
+
 	tpm_cmd.header.in = tpm_readpubek_header;
 	err = transmit_cmd(chip, &tpm_cmd, READ_PUBEK_RESULT_SIZE,
 			"attempting to read the PUBEK");