Re: [PATCH for-rc] RDMA/siw: Fix shift-out-of-bounds when call roundup_pow_of_two()

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Dec 07, 2020 at 11:37:28AM +0200, Kamal Heib wrote:
> When running the blktests over siw the following shift-out-of-bounds is
> reported, this is happening because the passed IRD or ORD from the ulp
> could be zero which will lead to unexpected behavior when calling
> roundup_pow_of_two(), fix that by blocking zero values of ORD or IRD.
> 
> UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13
> shift exponent 64 is too large for 64-bit type 'long unsigned int'
> CPU: 20 PID: 3957 Comm: kworker/u64:13 Tainted: G S     5.10.0-rc6 #2
> Hardware name: Dell Inc. PowerEdge R630/02C2CP, BIOS 2.1.5 04/11/2016
> Workqueue: iw_cm_wq cm_work_handler [iw_cm]
> Call Trace:
>  dump_stack+0x99/0xcb
>  ubsan_epilogue+0x5/0x40
>  __ubsan_handle_shift_out_of_bounds.cold.11+0xb4/0xf3
>  ? down_write+0x183/0x3d0
>  siw_qp_modify.cold.8+0x2d/0x32 [siw]
>  ? __local_bh_enable_ip+0xa5/0xf0
>  siw_accept+0x906/0x1b60 [siw]
>  ? xa_load+0x147/0x1f0
>  ? siw_connect+0x17a0/0x17a0 [siw]
>  ? lock_downgrade+0x700/0x700
>  ? siw_get_base_qp+0x1c2/0x340 [siw]
>  ? _raw_spin_unlock_irqrestore+0x39/0x40
>  iw_cm_accept+0x1f4/0x430 [iw_cm]
>  rdma_accept+0x3fa/0xb10 [rdma_cm]
>  ? check_flush_dependency+0x410/0x410
>  ? cma_rep_recv+0x570/0x570 [rdma_cm]
>  nvmet_rdma_queue_connect+0x1a62/0x2680 [nvmet_rdma]
>  ? nvmet_rdma_alloc_cmds+0xce0/0xce0 [nvmet_rdma]
>  ? lock_release+0x56e/0xcc0
>  ? lock_downgrade+0x700/0x700
>  ? lock_downgrade+0x700/0x700
>  ? __xa_alloc_cyclic+0xef/0x350
>  ? __xa_alloc+0x2d0/0x2d0
>  ? rdma_restrack_add+0xbe/0x2c0 [ib_core]
>  ? __ww_mutex_die+0x190/0x190
>  cma_cm_event_handler+0xf2/0x500 [rdma_cm]
>  iw_conn_req_handler+0x910/0xcb0 [rdma_cm]
>  ? _raw_spin_unlock_irqrestore+0x39/0x40
>  ? trace_hardirqs_on+0x1c/0x150
>  ? cma_ib_handler+0x8a0/0x8a0 [rdma_cm]
>  ? __kasan_kmalloc.constprop.7+0xc1/0xd0
>  cm_work_handler+0x121c/0x17a0 [iw_cm]
>  ? iw_cm_reject+0x190/0x190 [iw_cm]
>  ? trace_hardirqs_on+0x1c/0x150
>  process_one_work+0x8fb/0x16c0
>  ? pwq_dec_nr_in_flight+0x320/0x320
>  worker_thread+0x87/0xb40
>  ? __kthread_parkme+0xd1/0x1a0
>  ? process_one_work+0x16c0/0x16c0
>  kthread+0x35f/0x430
>  ? kthread_mod_delayed_work+0x180/0x180
>  ret_from_fork+0x22/0x30
> 
> Fixes: 6c52fdc244b5 ("rdma/siw: connection management")
> Signed-off-by: Kamal Heib <kamalheib1@gmail.com>
>  drivers/infiniband/sw/siw/siw_cm.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/sw/siw/siw_cm.c b/drivers/infiniband/sw/siw/siw_cm.c
> index 66764f7ef072..dff0b00cc55d 100644
> +++ b/drivers/infiniband/sw/siw/siw_cm.c
> @@ -1571,7 +1571,8 @@ int siw_accept(struct iw_cm_id *id, struct iw_cm_conn_param *params)
>  		qp->tx_ctx.gso_seg_limit = 0;
>  	}
>  	if (params->ord > sdev->attrs.max_ord ||
> -	    params->ird > sdev->attrs.max_ird) {
> +	    params->ird > sdev->attrs.max_ird ||
> +	    !params->ord || !params->ird) {
>  		siw_dbg_cep(

Are you sure this is the right place for this? Why not higher up? It
looks like the other iwarp drivers have the same problem

Jason