From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Date: Tue, 20 Jun 2017 11:38:02 +0200
Subject: [PATCH] tpm: fix a kernel memory leak in tpm-sysfs.c
References: bnc#1060662
Patch-mainline: 4.12.1
Git-commit: 13b47cfcfc60495cde216eef4c01040d76174cbe

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@obsidianresearch.com>
Tested-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/char/tpm/tpm-sysfs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index 59bd0b7b5959..c6fa9bef11cf 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -36,9 +36,10 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
 	ssize_t err;
 	int i, rc;
 	char *str = buf;
-
 	struct tpm_chip *chip = to_tpm_chip(dev);
 
+	memset(&tpm_cmd, 0, sizeof(tpm_cmd));
+
 	tpm_cmd.header.in = tpm_readpubek_header;
 	err = tpm_transmit_cmd(chip, NULL, &tpm_cmd, READ_PUBEK_RESULT_SIZE,
 			       READ_PUBEK_RESULT_MIN_BODY_SIZE, 0,
-- 
2.14.2