[PATCH 4.17 062/101] net: cxgb3_main: fix potential Spectre v1
From: Greg Kroah-Hartman
Date: Fri Jul 20 2018 - 08:44:02 EST
4.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
@@ -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 n
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;