Re: [PATCH] net: cxgb3_main: fix potential Spectre v1

[David Miller]

From: "Gustavo A. R. Silva" <gustavo@xxxxxxxxxxxxxx>
Date: Mon, 16 Jul 2018 20:59:58 -0500

> t.qset_idx 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/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2286 cxgb_extension_ioctl()
> warn: potential spectre issue 'adapter->msix_info'
> 
> Fix this by sanitizing t.qset_idx before using it to index
> adapter->msix_info
> 
> 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] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>

Applied, thanks.