7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christian Borntraeger commit f63eb4ee4a30fc5d8de07a229d92310e3c8d560c upstream. The cma_alloc bit as well as the response can contain old data. cma_release will not free the kmalloced memory in that case and the response code might leak kernel stack data to CAP_SYS_ADMIN users. Cc: stable@vger.kernel.org Signed-off-by: Christian Borntraeger Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman --- drivers/s390/char/vmcp.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/drivers/s390/char/vmcp.c +++ b/drivers/s390/char/vmcp.c @@ -104,13 +104,11 @@ static int vmcp_open(struct inode *inode if (!capable(CAP_SYS_ADMIN)) return -EPERM; - session = kmalloc_obj(*session); + session = kzalloc_obj(*session); if (!session) return -ENOMEM; session->bufsize = PAGE_SIZE; - session->response = NULL; - session->resp_size = 0; mutex_init(&session->mutex); file->private_data = session; return nonseekable_open(inode, file);