From: Artem Bityutskiy Date: Thu, 5 Jan 2012 08:47:18 +0000 (+0200) Subject: UBI: fix use-after-free on error path X-Git-Tag: v2.6.32.55~22 X-Git-Url: https://git.fsl.cs.sunysb.edu/?a=commitdiff_plain;h=78771467f80f450962913dfabe495e4fb517f9b2;p=unionfs-2.6.39.y.git UBI: fix use-after-free on error path commit e57e0d8e818512047fe379157c3f77f1b9fabffb upstream. When we fail to erase a PEB, we free the corresponding erase entry object, but then re-schedule this object if the error code was something like -EAGAIN. Obviously, it is a bug to use the object after we have freed it. Reported-by: Emese Revfy Signed-off-by: Artem Bityutskiy Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c index 600c7229d5c..ca42c00ec85 100644 --- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -1036,7 +1036,6 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, ubi_err("failed to erase PEB %d, error %d", pnum, err); kfree(wl_wrk); - kmem_cache_free(ubi_wl_entry_slab, e); if (err == -EINTR || err == -ENOMEM || err == -EAGAIN || err == -EBUSY) { @@ -1049,14 +1048,16 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, goto out_ro; } return err; - } else if (err != -EIO) { + } + + kmem_cache_free(ubi_wl_entry_slab, e); + if (err != -EIO) /* * If this is not %-EIO, we have no idea what to do. Scheduling * this physical eraseblock for erasure again would cause * errors again and again. Well, lets switch to R/O mode. */ goto out_ro; - } /* It is %-EIO, the PEB went bad */