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    RDMA/cma: Ensure rdma_addr_cancel() happens before issuing more requests · 8edf695c
    Jason Gunthorpe 提交于
    mainline inclusion
    from mainline-v5.15-rc4
    commit 305d568b
    category: bugfix
    bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6X49E
    CVE: CVE-2023-2176
    
    Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=305d568b72f17f674155a2a8275f865f207b3808
    
    ---------------------------
    
    The FSM can run in a circle allowing rdma_resolve_ip() to be called twice
    on the same id_priv. While this cannot happen without going through the
    work, it violates the invariant that the same address resolution
    background request cannot be active twice.
    
           CPU 1                                  CPU 2
    
    rdma_resolve_addr():
      RDMA_CM_IDLE -> RDMA_CM_ADDR_QUERY
      rdma_resolve_ip(addr_handler)  #1
    
    			 process_one_req(): for #1
                              addr_handler():
                                RDMA_CM_ADDR_QUERY -> RDMA_CM_ADDR_BOUND
                                mutex_unlock(&id_priv->handler_mutex);
                                [.. handler still running ..]
    
    rdma_resolve_addr():
      RDMA_CM_ADDR_BOUND -> RDMA_CM_ADDR_QUERY
      rdma_resolve_ip(addr_handler)
        !! two requests are now on the req_list
    
    rdma_destroy_id():
     destroy_id_handler_unlock():
      _destroy_id():
       cma_cancel_operation():
        rdma_addr_cancel()
    
                              // process_one_req() self removes it
    		          spin_lock_bh(&lock);
                               cancel_delayed_work(&req->work);
    	                   if (!list_empty(&req->list)) == true
    
          ! rdma_addr_cancel() returns after process_on_req #1 is done
    
       kfree(id_priv)
    
    			 process_one_req(): for #2
                              addr_handler():
    	                    mutex_lock(&id_priv->handler_mutex);
                                !! Use after free on id_priv
    
    rdma_addr_cancel() expects there to be one req on the list and only
    cancels the first one. The self-removal behavior of the work only happens
    after the handler has returned. This yields a situations where the
    req_list can have two reqs for the same "handle" but rdma_addr_cancel()
    only cancels the first one.
    
    The second req remains active beyond rdma_destroy_id() and will
    use-after-free id_priv once it inevitably triggers.
    
    Fix this by remembering if the id_priv has called rdma_resolve_ip() and
    always cancel before calling it again. This ensures the req_list never
    gets more than one item in it and doesn't cost anything in the normal flow
    that never uses this strange error path.
    
    Link: https://lore.kernel.org/r/0-v1-3bc675b8006d+22-syz_cancel_uaf_jgg@nvidia.com
    Cc: stable@vger.kernel.org
    Fixes: e51060f0 ("IB: IP address based RDMA connection manager")
    Reported-by: syzbot+dc3dfba010d7671e05f5@syzkaller.appspotmail.com
    Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
    (cherry picked from commit 305d568b)
    Signed-off-by: NLiu Jian <liujian56@huawei.com>
    
    Conflicts:
    	drivers/infiniband/core/cma_priv.h
    Reviewed-by: NYue Haibing <yuehaibing@huawei.com>
    Reviewed-by: NWang Weiyang <wangweiyang2@huawei.com>
    Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>
    8edf695c
cma_priv.h 3.7 KB