From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Date: Tue, 20 Jun 2017 09:38:02 +0000 (+0200)
Subject: tpm: fix a kernel memory leak in tpm-sysfs.c
X-Git-Tag: v3.2.94~39
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dc66bea5b05e9081b3b5bf1639cc7cd541f0c670;p=thirdparty%2Fkernel%2Fstable.git

tpm: fix a kernel memory leak in tpm-sysfs.c

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>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index f7395c438a006..2c71cc4f30392 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -879,9 +879,10 @@ ssize_t tpm_show_pubek(struct device *dev, struct device_attribute *attr,
 	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");