Re: [PATCH 0/1] can: fix a potential UAF access in j1939_session_deactivate()

[Greg KH <greg@kroah.com>]

On Tue, Jul 13, 2021 at 01:21:44PM -0700, Xiaochen Zou wrote:
> 
> Xiaochen Zou (1):
>   can: fix a potential UAF access in j1939_session_deactivate(). Both
>     session and session->priv may be freed in
>     j1939_session_deactivate_locked(). It leads to potential UAF read
>     and write in j1939_session_list_unlock(). The free chain is
> 
> j1939_session_deactivate_locked()->j1939_session_put()->__j1939_session_release()->j1939_session_destroy().
>     To fix this bug, I moved j1939_session_put() behind
>     j1939_session_deactivate_locked(), and guarded it with a check of
>     active since the session would be freed only if active is true.
> 
>  net/can/j1939/transport.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> -- 
> 2.17.1


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