Xen/gnttab: handle p2m update errors on a per-slot basis
stable inclusion from linux-4.19.179 commit 1a999d25ef536a14f6a7c25778836857adfba3f8 CVE: CVE-2021-28038 -------------------------------- commit 8310b77b48c5558c140e7a57a702e7819e62f04e upstream. Bailing immediately from set_foreign_p2m_mapping() upon a p2m updating error leaves the full batch in an ambiguous state as far as the caller is concerned. Instead flags respective slots as bad, unmapping what was mapped there right away. HYPERVISOR_grant_table_op()'s return value and the individual unmap slots' status fields get used only for a one-time - there's not much we can do in case of a failure. Note that there's no GNTST_enomem or alike, so GNTST_general_error gets used. The map ops' handle fields get overwritten just to be on the safe side. This is part of XSA-367. Cc: <stable@vger.kernel.org> Signed-off-by:Jan Beulich <jbeulich@suse.com> Reviewed-by:
Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/96cccf5d-e756-5f53-b91a-ea269bfb9be0@suse.com Signed-off-by:
Juergen Gross <jgross@suse.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
Yang Yingliang <yangyingliang@huawei.com> Reviewed-by:
Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by:
Yang Yingliang <yangyingliang@huawei.com> Signed-off-by:
Cheng Jian <cj.chengjian@huawei.com>
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