linux-kernel - [06/27] UBI: fix use-after-free on error path

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20120123234202.200082801@clark.kroah.org>
Date:	Mon, 23 Jan 2012 15:40:52 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk,
	Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
Subject: [06/27] UBI: fix use-after-free on error path

2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------

From: Artem Bityutskiy <artem.bityutskiy@...ux.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@...il.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.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 */
 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/