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

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.

Cc: stable@vger.kernel.org
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>

diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index 938d03ce30fe00a1232441dbf15c92367564012f..86f38d239476ab00a70db97640e0ff843c7dd3de 100644 (file)
--- 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,