[PATCH RFC] ubi: gluebi: Fix NULL pointer dereference caused by ftl notifier
ZhaoLong Wang
wangzhaolong1 at huawei.com
Thu Oct 12 04:31:18 PDT 2023
Friendly ping ...
> If both flt.ko and gluebi.ko are loaded, the notiier of ftl
> triggers NULL pointer dereference when trying to visit
> ‘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
> mtd_read_oob
> 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 accesses 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.
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