From 9d092603cc306ee6edfe917bf9ab8beb5f32d7bc Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Thu, 20 Dec 2012 10:31:11 +0000 Subject: [PATCH] xen-blkback: do not leak mode property "be->mode" is obtained from xenbus_read(), which does a kmalloc() for the message body. The short string is never released, so do it along with freeing "be" itself, and make sure the string isn't kept when backend_changed() doesn't complete successfully (which made it desirable to slightly re-structure that function, so that the error cleanup can be done in one place). Reported-by: Olaf Hering CC: stable@vger.kernel.org Signed-off-by: Jan Beulich Signed-off-by: Konrad Rzeszutek Wilk --- drivers/block/xen-blkback/xenbus.c | 49 +++++++++++++++--------------- 1 file changed, 24 insertions(+), 25 deletions(-) diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 63980722db41..5e237f630c47 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -367,6 +367,7 @@ static int xen_blkbk_remove(struct xenbus_device *dev) be->blkif = NULL; } + kfree(be->mode); kfree(be); dev_set_drvdata(&dev->dev, NULL); return 0; @@ -502,6 +503,7 @@ static void backend_changed(struct xenbus_watch *watch, = container_of(watch, struct backend_info, backend_watch); struct xenbus_device *dev = be->dev; int cdrom = 0; + unsigned long handle; char *device_type; DPRINTK(""); @@ -521,10 +523,10 @@ static void backend_changed(struct xenbus_watch *watch, return; } - if ((be->major || be->minor) && - ((be->major != major) || (be->minor != minor))) { - pr_warn(DRV_PFX "changing physical device (from %x:%x to %x:%x) not supported.\n", - be->major, be->minor, major, minor); + if (be->major | be->minor) { + if (be->major != major || be->minor != minor) + pr_warn(DRV_PFX "changing physical device (from %x:%x to %x:%x) not supported.\n", + be->major, be->minor, major, minor); return; } @@ -542,36 +544,33 @@ static void backend_changed(struct xenbus_watch *watch, kfree(device_type); } - if (be->major == 0 && be->minor == 0) { - /* Front end dir is a number, which is used as the handle. */ - - char *p = strrchr(dev->otherend, '/') + 1; - long handle; - err = strict_strtoul(p, 0, &handle); - if (err) - return; + /* Front end dir is a number, which is used as the handle. */ + err = strict_strtoul(strrchr(dev->otherend, '/') + 1, 0, &handle); + if (err) + return; - be->major = major; - be->minor = minor; + be->major = major; + be->minor = minor; - err = xen_vbd_create(be->blkif, handle, major, minor, - (NULL == strchr(be->mode, 'w')), cdrom); - if (err) { - be->major = 0; - be->minor = 0; - xenbus_dev_fatal(dev, err, "creating vbd structure"); - return; - } + err = xen_vbd_create(be->blkif, handle, major, minor, + !strchr(be->mode, 'w'), cdrom); + if (err) + xenbus_dev_fatal(dev, err, "creating vbd structure"); + else { err = xenvbd_sysfs_addif(dev); if (err) { xen_vbd_free(&be->blkif->vbd); - be->major = 0; - be->minor = 0; xenbus_dev_fatal(dev, err, "creating sysfs entries"); - return; } + } + if (err) { + kfree(be->mode); + be->mode = NULL; + be->major = 0; + be->minor = 0; + } else { /* We're potentially connected now */ xen_update_blkif_status(be->blkif); } -- 2.39.2