From: Dan Carpenter dan.carpenter@oracle.com

stable inclusion from stable-v4.19.209 commit 66f74ba9be9daf9c47fface6af3677f602774f6b category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4M2 CVE: CVE-2021-47361

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit 25a1433216489de4abc889910f744e952cb6dbae upstream.

There are two bugs: 1) If ida_simple_get() fails then this code calls put_device(carrier) but we haven't yet called get_device(carrier) and probably that leads to a use after free. 2) After device_initialize() then we need to use put_device() to release the bus. This will free the internal resources tied to the device and call mcb_free_bus() which will free the rest.

Fixes: 5d9e2ab9fea4 ("mcb: Implement bus->dev.release callback") Fixes: 18d288198099 ("mcb: Correctly initialize the bus's device") Cc: stable@vger.kernel.org Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Johannes Thumshirn jth@kernel.org Link: https://lore.kernel.org/r/32e160cf6864ce77f9d62948338e24db9fd8ead9.163093131... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Hui Tang tanghui20@huawei.com --- drivers/mcb/mcb-core.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/mcb/mcb-core.c b/drivers/mcb/mcb-core.c index cee4f28baf95..4a2002ba2e23 100644 --- a/drivers/mcb/mcb-core.c +++ b/drivers/mcb/mcb-core.c @@ -280,8 +280,8 @@ struct mcb_bus *mcb_alloc_bus(struct device *carrier)

bus_nr = ida_simple_get(&mcb_ida, 0, 0, GFP_KERNEL); if (bus_nr < 0) { - rc = bus_nr; - goto err_free; + kfree(bus); + return ERR_PTR(bus_nr); }

bus->bus_nr = bus_nr; @@ -296,12 +296,12 @@ struct mcb_bus *mcb_alloc_bus(struct device *carrier) dev_set_name(&bus->dev, "mcb:%d", bus_nr); rc = device_add(&bus->dev); if (rc) - goto err_free; + goto err_put;

return bus; -err_free: - put_device(carrier); - kfree(bus); + +err_put: + put_device(&bus->dev); return ERR_PTR(rc); } EXPORT_SYMBOL_GPL(mcb_alloc_bus);