| Message ID | 20191130093317.31352-1-wenyang@linux.alibaba.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | UBI: fix use after free in ubi_remove_volume() | expand |
Reviewed-by: Hou Tao <houtao1@huawei.com> On 2019/11/30 17:33, Wen Yang wrote: > We can't use "vol" after it has been freed. > > Fixes: 493cfaeaa0c9 ("mtd: utilize new cdev_device_add helper function") > Signed-off-by: Wen Yang <wenyang@linux.alibaba.com> > Cc: Richard Weinberger <richard@nod.at> > Cc: Miquel Raynal <miquel.raynal@bootlin.com> > Cc: Vignesh Raghavendra <vigneshr@ti.com> > Cc: linux-mtd@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > --- > drivers/mtd/ubi/vmt.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c > index 139ee13..8ff1478 100644 > --- a/drivers/mtd/ubi/vmt.c > +++ b/drivers/mtd/ubi/vmt.c > @@ -375,7 +375,6 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl) > } > > cdev_device_del(&vol->cdev, &vol->dev); > - put_device(&vol->dev); > > spin_lock(&ubi->volumes_lock); > ubi->rsvd_pebs -= reserved_pebs; > @@ -388,6 +387,8 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl) > if (!no_vtbl) > self_check_volumes(ubi); > > + put_device(&vol->dev); > + > return 0; > > out_err: >
Hi, On 2019/12/3 21:13, Hou Tao wrote: > Reviewed-by: Hou Tao <houtao1@huawei.com> > Sorry for my early conclusion. The reference of ubi_volume had already been increased in ubi_open_volume() in ubi_cdev_ioctl(), so this reference dropped in ubi_remove_volume() will not be the last one, and there will no use-after-free problem. Regards, Tao > On 2019/11/30 17:33, Wen Yang wrote: >> We can't use "vol" after it has been freed. >> >> Fixes: 493cfaeaa0c9 ("mtd: utilize new cdev_device_add helper function") >> Signed-off-by: Wen Yang <wenyang@linux.alibaba.com> >> Cc: Richard Weinberger <richard@nod.at> >> Cc: Miquel Raynal <miquel.raynal@bootlin.com> >> Cc: Vignesh Raghavendra <vigneshr@ti.com> >> Cc: linux-mtd@lists.infradead.org >> Cc: linux-kernel@vger.kernel.org >> --- >> drivers/mtd/ubi/vmt.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c >> index 139ee13..8ff1478 100644 >> --- a/drivers/mtd/ubi/vmt.c >> +++ b/drivers/mtd/ubi/vmt.c >> @@ -375,7 +375,6 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl) >> } >> >> cdev_device_del(&vol->cdev, &vol->dev); >> - put_device(&vol->dev); >> >> spin_lock(&ubi->volumes_lock); >> ubi->rsvd_pebs -= reserved_pebs; >> @@ -388,6 +387,8 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl) >> if (!no_vtbl) >> self_check_volumes(ubi); >> >> + put_device(&vol->dev); >> + >> return 0; >> >> out_err: >> > > > ______________________________________________________ > Linux MTD discussion mailing list > http://lists.infradead.org/mailman/listinfo/linux-mtd/ > >
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c index 139ee13..8ff1478 100644 --- a/drivers/mtd/ubi/vmt.c +++ b/drivers/mtd/ubi/vmt.c @@ -375,7 +375,6 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl) } cdev_device_del(&vol->cdev, &vol->dev); - put_device(&vol->dev); spin_lock(&ubi->volumes_lock); ubi->rsvd_pebs -= reserved_pebs; @@ -388,6 +387,8 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl) if (!no_vtbl) self_check_volumes(ubi); + put_device(&vol->dev); + return 0; out_err:
We can't use "vol" after it has been freed. Fixes: 493cfaeaa0c9 ("mtd: utilize new cdev_device_add helper function") Signed-off-by: Wen Yang <wenyang@linux.alibaba.com> Cc: Richard Weinberger <richard@nod.at> Cc: Miquel Raynal <miquel.raynal@bootlin.com> Cc: Vignesh Raghavendra <vigneshr@ti.com> Cc: linux-mtd@lists.infradead.org Cc: linux-kernel@vger.kernel.org --- drivers/mtd/ubi/vmt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)