Re: [PATCH v3 for-rc] RDMA/siw: Enforce IB_ACCESS_REMOTE_READ for read responses

[sashiko-bot@kernel.org]

> When generating an RDMA READ response (SIW_OP_READ_RESPONSE),
> siw_check_sgl_tx() unconditionally passes 0 as the required permission
> mask:
> 
>     /* Reference memory to be tx'd w/o checking access for LOCAL_READ */
>     rv = siw_check_sgl_tx(qp->pd, wqe, 0);
> 
> Because perms is 0, siw_check_mem()'s authorization test:
>     if ((mem->perms & perms) < perms)
> evaluates to (mem->perms & 0) < 0, which is always false. Consequently,
> an untrusted remote peer can issue an RDMA Read targeting any valid
> STag in the Protection Domain, even if the memory was registered strictly
> as write-only (IB_ACCESS_REMOTE_WRITE) without IB_ACCESS_REMOTE_READ.
> 
> Enforce that the target memory region was granted IB_ACCESS_REMOTE_READ
> when answering SIW_OP_READ_RESPONSE work queue entries, while preserving
> perms = 0 for standard local sends.
> 
> Fixes: b9be6f18cf9e ("rdma/siw: transmit path")
> Cc: stable@vger.kernel.org
> Signed-off-by: Haitam Lazaar <haitam@lazaarsec.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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