| Message ID | 20231220024619.2138625-1-wangzhaolong1@huawei.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [V4] mtd: Fix gluebi NULL pointer dereference caused by ftl notifier | expand |
On Wed, 2023-12-20 at 02:46:19 UTC, ZhaoLong Wang wrote: > 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@nod.at/ [2] > Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com> > Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com> > Acked-by: Richard Weinberger <richard@nod.at> Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks. Miquel
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c index ff18636e0889..5bc32108ca03 100644 --- a/drivers/mtd/mtd_blkdevs.c +++ b/drivers/mtd/mtd_blkdevs.c @@ -463,7 +463,7 @@ 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) @@ -503,7 +503,7 @@ int register_mtd_blktrans(struct mtd_blktrans_ops *tr) mutex_lock(&mtd_table_mutex); 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); return 0;
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@nod.at/ [2] Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com> Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com> Acked-by: Richard Weinberger <richard@nod.at> --- drivers/mtd/mtd_blkdevs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)