From: "Jan Beulich" <JBeulich@suse.com>
To: "Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>
Cc: "Olaf Hering" <olaf@aepfle.de>, "Jens Axboe" <axboe@kernel.dk>,
"xen-devel" <xen-devel@lists.xen.org>,
<linux-kernel@vger.kernel.org>
Subject: [PATCH] xen-blkback: do not leak mode property
Date: Thu, 20 Dec 2012 10:31:11 +0000 [thread overview]
Message-ID: <50D2F6FF02000078000B1BC5@nat28.tlf.novell.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 3113 bytes --]
"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 <olaf@aepfle.de>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
drivers/block/xen-blkback/xenbus.c | 49 ++++++++++++++++++-------------------
1 file changed, 24 insertions(+), 25 deletions(-)
--- 3.7/drivers/block/xen-blkback/xenbus.c
+++ 3.7-xen-blkback-mode-leak/drivers/block/xen-blkback/xenbus.c
@@ -366,6 +366,7 @@ static int xen_blkbk_remove(struct xenbu
be->blkif = NULL;
}
+ kfree(be->mode);
kfree(be);
dev_set_drvdata(&dev->dev, NULL);
return 0;
@@ -501,6 +502,7 @@ static void backend_changed(struct xenbu
= container_of(watch, struct backend_info, backend_watch);
struct xenbus_device *dev = be->dev;
int cdrom = 0;
+ unsigned long handle;
char *device_type;
DPRINTK("");
@@ -520,10 +522,10 @@ static void backend_changed(struct xenbu
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;
}
@@ -541,36 +543,33 @@ static void backend_changed(struct xenbu
kfree(device_type);
}
- if (be->major == 0 && be->minor == 0) {
- /* Front end dir is a number, which is used as the handle. */
+ /* Front end dir is a number, which is used as the handle. */
+ err = strict_strtoul(strrchr(dev->otherend, '/') + 1, 0, &handle);
+ if (err)
+ return;
- char *p = strrchr(dev->otherend, '/') + 1;
- long handle;
- err = strict_strtoul(p, 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);
}
[-- Attachment #2: linux-3.7-xen-blkback-mode-leak.patch --]
[-- Type: text/plain, Size: 3149 bytes --]
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 <olaf@aepfle.de>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
drivers/block/xen-blkback/xenbus.c | 49 ++++++++++++++++++-------------------
1 file changed, 24 insertions(+), 25 deletions(-)
--- 3.7/drivers/block/xen-blkback/xenbus.c
+++ 3.7-xen-blkback-mode-leak/drivers/block/xen-blkback/xenbus.c
@@ -366,6 +366,7 @@ static int xen_blkbk_remove(struct xenbu
be->blkif = NULL;
}
+ kfree(be->mode);
kfree(be);
dev_set_drvdata(&dev->dev, NULL);
return 0;
@@ -501,6 +502,7 @@ static void backend_changed(struct xenbu
= container_of(watch, struct backend_info, backend_watch);
struct xenbus_device *dev = be->dev;
int cdrom = 0;
+ unsigned long handle;
char *device_type;
DPRINTK("");
@@ -520,10 +522,10 @@ static void backend_changed(struct xenbu
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;
}
@@ -541,36 +543,33 @@ static void backend_changed(struct xenbu
kfree(device_type);
}
- if (be->major == 0 && be->minor == 0) {
- /* Front end dir is a number, which is used as the handle. */
+ /* Front end dir is a number, which is used as the handle. */
+ err = strict_strtoul(strrchr(dev->otherend, '/') + 1, 0, &handle);
+ if (err)
+ return;
- char *p = strrchr(dev->otherend, '/') + 1;
- long handle;
- err = strict_strtoul(p, 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);
}
next reply other threads:[~2012-12-20 10:31 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-20 10:31 Jan Beulich [this message]
2013-01-11 17:36 ` Konrad Rzeszutek Wilk
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