4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: ZhaoLong Wang <wangzhaolong1@xxxxxxxxxx>
[ Upstream commit a43bdc376deab5fff1ceb93dca55bcab8dbdc1d6 ]
If both ftl.ko and gluebi.ko are loaded, the notifier of ftl
triggers NULL pointer dereference when trying to access
‘gluebi->desc’ in gluebi_read().
ubi_gluebi_init
ubi_register_volume_notifier
ubi_enumerate_volumes
ubi_notify_all
gluebi_notify nb->notifier_call()
gluebi_create
mtd_device_register
mtd_device_parse_register
add_mtd_device
blktrans_notify_add not->add()
ftl_add_mtd tr->add_mtd()
scan_header
mtd_read
mtd_read_oob
mtd_read_oob_std
gluebi_read mtd->read()
gluebi->desc - NULL
Detailed reproduction information available at the Link [1],
In the normal case, obtain gluebi->desc in the gluebi_get_device(),
and access gluebi->desc in the gluebi_read(). However,
gluebi_get_device() is not executed in advance in the
ftl_add_mtd() process, which leads to NULL pointer dereference.
The solution for the gluebi module is to run jffs2 on the UBI
volume without considering working with ftl or mtdblock [2].
Therefore, this problem can be avoided by preventing gluebi from
creating the mtdblock device after creating mtd partition of the
type MTD_UBIVOLUME.
Fixes: 2ba3d76a1e29 ("UBI: make gluebi a separate module")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217992 [1]
Link: https://lore.kernel.org/lkml/441107100.23734.1697904580252.JavaMail.zimbra@xxxxxx/ [2]
Signed-off-by: ZhaoLong Wang <wangzhaolong1@xxxxxxxxxx>
Reviewed-by: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
Acked-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Link: https://lore.kernel.org/linux-mtd/20231220024619.2138625-1-wangzhaolong1@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/mtd/mtd_blkdevs.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 6a41dfa3c36b..a9aa1b518d81 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -521,7 +521,7 @@ static void blktrans_notify_add(struct mtd_info *mtd)
{
struct mtd_blktrans_ops *tr;
- if (mtd->type == MTD_ABSENT)
+ if (mtd->type == MTD_ABSENT || mtd->type == MTD_UBIVOLUME)
return;
list_for_each_entry(tr, &blktrans_majors, list)
@@ -564,7 +564,7 @@ int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
list_add(&tr->list, &blktrans_majors);
mtd_for_each_device(mtd)
- if (mtd->type != MTD_ABSENT)
+ if (mtd->type != MTD_ABSENT && mtd->type != MTD_UBIVOLUME)
tr->add_mtd(tr, mtd);
mutex_unlock(&mtd_table_mutex);
--
2.43.0
