Re: Use-after-free access in j1939_session_deactivate

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.

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Marc