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Commit 3caea515 authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by Greg Kroah-Hartman
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net: cxgb3_main: fix potential Spectre v1 

commit 676bcfece19f83621e905aa55b5ed2d45cc4f2d3 upstream.

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@vger.kernel.org
Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d8530e89

drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c

+2 −0
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ 
#include <linux/sched.h>

#include <linux/slab.h>

#include <linux/uaccess.h>

#include <linux/nospec.h>



#include "common.h"

#include "cxgb3_ioctl.h"
@@ -2268,6 +2269,7 @@ static int cxgb_extension_ioctl(struct net_device *dev, void __user *useraddr) 


		if (t.qset_idx >= nqsets)

			return -EINVAL;

		t.qset_idx = array_index_nospec(t.qset_idx, nqsets);



		q = &adapter->params.sge.qset[q1 + t.qset_idx];

		t.rspq_size = q->rspq_size;