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From d28f4336976d7994bca4de5d2eb3a4b6cc003be8 Mon Sep 17 00:00:00 2001
From: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Date: Thu, 5 Jan 2012 10:47:18 +0200
Subject: [PATCH 030/130] 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 <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(-)
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 277c429..0696e36 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -1052,7 +1052,6 @@ 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) {
@@ -1065,14 +1064,16 @@ 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 */
--
1.7.9.4
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