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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-05-19 01:13:42 (GMT)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-06-16 07:52:33 (GMT)
commit14450abb38eb72e5a37743cb0e67cd005173d9a0 (patch)
tree23cc51ec5f5b22ee618a13ad3084e451e068418b
parent8da07ee9e433f3af74f126c5bfd1a1a44d0aaeef (diff)
usbip: vhci_sysfs: fix potential Spectre v1
commit a0d6ec88090d7b1b008429c44532a388e29bb1bd upstream. pdev_nr and rhport can be 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/usb/usbip/vhci_sysfs.c:238 detach_store() warn: potential spectre issue 'vhcis' drivers/usb/usbip/vhci_sysfs.c:328 attach_store() warn: potential spectre issue 'vhcis' drivers/usb/usbip/vhci_sysfs.c:338 attach_store() warn: potential spectre issue 'vhci->vhci_hcd_ss->vdev' drivers/usb/usbip/vhci_sysfs.c:340 attach_store() warn: potential spectre issue 'vhci->vhci_hcd_hs->vdev' Fix this by sanitizing pdev_nr and rhport before using them to index vhcis and vhci->vhci_hcd_ss->vdev respectively. 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: Gustavo A. R. Silva <gustavo@embeddedor.com> Acked-by: Shuah Khan (Samsung OSG) <shuah@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/usbip/vhci_sysfs.c24
1 files changed, 16 insertions, 8 deletions
diff --git a/drivers/usb/usbip/vhci_sysfs.c b/drivers/usb/usbip/vhci_sysfs.c
index c287ccc..e8a008d 100644
--- a/drivers/usb/usbip/vhci_sysfs.c
+++ b/drivers/usb/usbip/vhci_sysfs.c
@@ -24,6 +24,9 @@
#include <linux/platform_device.h>
#include <linux/slab.h>
+/* Hardening for Spectre-v1 */
+#include <linux/nospec.h>
+
#include "usbip_common.h"
#include "vhci.h"
@@ -181,16 +184,20 @@ static int vhci_port_disconnect(struct vhci_hcd *vhci, __u32 rhport)
return 0;
}
-static int valid_port(__u32 pdev_nr, __u32 rhport)
+static int valid_port(__u32 *pdev_nr, __u32 *rhport)
{
- if (pdev_nr >= vhci_num_controllers) {
- pr_err("pdev %u\n", pdev_nr);
+ if (*pdev_nr >= vhci_num_controllers) {
+ pr_err("pdev %u\n", *pdev_nr);
return 0;
}
- if (rhport >= VHCI_HC_PORTS) {
- pr_err("rhport %u\n", rhport);
+ *pdev_nr = array_index_nospec(*pdev_nr, vhci_num_controllers);
+
+ if (*rhport >= VHCI_HC_PORTS) {
+ pr_err("rhport %u\n", *rhport);
return 0;
}
+ *rhport = array_index_nospec(*rhport, VHCI_HC_PORTS);
+
return 1;
}
@@ -207,7 +214,7 @@ static ssize_t store_detach(struct device *dev, struct device_attribute *attr,
pdev_nr = port_to_pdev_nr(port);
rhport = port_to_rhport(port);
- if (!valid_port(pdev_nr, rhport))
+ if (!valid_port(&pdev_nr, &rhport))
return -EINVAL;
hcd = platform_get_drvdata(*(vhci_pdevs + pdev_nr));
@@ -226,7 +233,8 @@ static ssize_t store_detach(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR(detach, S_IWUSR, NULL, store_detach);
-static int valid_args(__u32 pdev_nr, __u32 rhport, enum usb_device_speed speed)
+static int valid_args(__u32 *pdev_nr, __u32 *rhport,
+ enum usb_device_speed speed)
{
if (!valid_port(pdev_nr, rhport)) {
return 0;
@@ -288,7 +296,7 @@ static ssize_t store_attach(struct device *dev, struct device_attribute *attr,
sockfd, devid, speed);
/* check received parameters */
- if (!valid_args(pdev_nr, rhport, speed))
+ if (!valid_args(&pdev_nr, &rhport, speed))
return -EINVAL;
hcd = platform_get_drvdata(*(vhci_pdevs + pdev_nr));