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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-08-16 14:06:46 -0500
committerBjorn Helgaas <bhelgaas@google.com>2018-09-11 08:47:40 -0500
commit46feb6b495f7628a6dbf36c4e6d80faf378372d4 (patch)
treea4118efdd6112248604eab81f3e8930bb0d69601 /drivers/pci
parent50ca031b51106b1b46162d4e9ecccb7edc95682f (diff)
switchtec: Fix Spectre v1 vulnerability
p.port can is 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/pci/switch/switchtec.c:912 ioctl_port_to_pff() warn: potential spectre issue 'pcfg->dsp_pff_inst_id' [r] Fix this by sanitizing p.port before using it to index pcfg->dsp_pff_inst_id 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 Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Logan Gunthorpe <logang@deltatee.com> Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/switch/switchtec.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
index 9940cc70f38b..54a8b30dda38 100644
--- a/drivers/pci/switch/switchtec.c
+++ b/drivers/pci/switch/switchtec.c
@@ -14,6 +14,8 @@
#include <linux/poll.h>
#include <linux/wait.h>
+#include <linux/nospec.h>
+
MODULE_DESCRIPTION("Microsemi Switchtec(tm) PCIe Management Driver");
MODULE_VERSION("0.1");
MODULE_LICENSE("GPL");
@@ -909,6 +911,8 @@ static int ioctl_port_to_pff(struct switchtec_dev *stdev,
default:
if (p.port > ARRAY_SIZE(pcfg->dsp_pff_inst_id))
return -EINVAL;
+ p.port = array_index_nospec(p.port,
+ ARRAY_SIZE(pcfg->dsp_pff_inst_id) + 1);
p.pff = ioread32(&pcfg->dsp_pff_inst_id[p.port - 1]);
break;
}