On 7/13/21 9:30 AM, Xiaochen Zou wrote:

j1939_session_destroy() will free both session and session->priv. It
leads to multiple use-after-free read and write in
j1939_session_deactivate() when session was freed in
j1939_session_deactivate_locked(). 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.

Please include your Signed-off-by.
See
https://elixir.bootlin.com/linux/v5.12/source/Documentation/process/submitting-patches.rst#L356

Marc

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