Re: [PATCH] RDMA/ucma: Fix Spectre v1 vulnerability

From: Doug Ledford
Date: Tue Oct 16 2018 - 12:49:49 EST

On Tue, 2018-10-16 at 16:59 +0200, Gustavo A. R. Silva wrote:
> hdr.cmd can be indirectly controlled by user-space, hence leading to
> a potential exploitation of the Spectre variant 1 vulnerability.
> This issue was detected with the help of Smatch:
> drivers/infiniband/core/ucma.c:1686 ucma_write() warn: potential
> spectre issue 'ucma_cmd_table' [r] (local cap)
> Fix this by sanitizing hdr.cmd before using it to index
> ucm_cmd_table.
> Notice that given that speculation windows are large, the policy is
> to kill the speculation on the first load and not worry if it can be
> completed with a dependent load/store [1].
> [1]
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>

Thanks, applied to for-rc.

Doug Ledford <dledford@xxxxxxxxxx>
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