6.1-stable review patch. If anyone has any objections, please let me know.
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From: Namjae Jeon linkinjeon@kernel.org
commit 15a9605f8d69dc85005b1a00c31a050b8625e1aa upstream.
In multichannel mode, UAF issue can occur in session_deregister when the second channel sets up a session through the connection of the first channel. session that is freed through the global session table can be accessed again through ->sessions of connection.
Cc: stable@vger.kernel.org Reported-by: Norbert Szetei norbert@doyensec.com Tested-by: Norbert Szetei norbert@doyensec.com Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/smb/server/mgmt/user_session.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/fs/smb/server/mgmt/user_session.c +++ b/fs/smb/server/mgmt/user_session.c @@ -229,6 +229,9 @@ void ksmbd_sessions_deregister(struct ks if (!ksmbd_chann_del(conn, sess) && xa_empty(&sess->ksmbd_chann_list)) { hash_del(&sess->hlist); + down_write(&conn->session_lock); + xa_erase(&conn->sessions, sess->id); + up_write(&conn->session_lock); ksmbd_session_destroy(sess); } }