Messages in this thread Patch in this message | | | Date | Mon, 23 Jan 2012 15:40:52 -0800 | From | Greg KH <> | Subject | [06/27] UBI: fix use-after-free on error path |
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2.6.32-longterm review patch. If anyone has any objections, please let me know.
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From: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
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 <re.emese@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/mtd/ubi/wl.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
--- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -1036,7 +1036,6 @@ static int erase_worker(struct ubi_devic 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_devic 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 */
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