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: sta...@vger.kernel.org Signed-off-by: Gustavo A. R. Silva <gust...@embeddedor.com> --- drivers/usb/usbip/vhci_sysfs.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/usb/usbip/vhci_sysfs.c b/drivers/usb/usbip/vhci_sysfs.c index 4880838..9045888 100644 --- a/drivers/usb/usbip/vhci_sysfs.c +++ b/drivers/usb/usbip/vhci_sysfs.c @@ -10,6 +10,8 @@ #include <linux/platform_device.h> #include <linux/slab.h> +#include <linux/nospec.h> + #include "usbip_common.h" #include "vhci.h" @@ -235,6 +237,8 @@ static ssize_t detach_store(struct device *dev, struct device_attribute *attr, if (!valid_port(pdev_nr, rhport)) return -EINVAL; + pdev_nr = array_index_nospec(pdev_nr, vhci_num_controllers); + rhport = array_index_nospec(rhport, VHCI_HC_PORTS); hcd = platform_get_drvdata(vhcis[pdev_nr].pdev); if (hcd == NULL) { dev_err(dev, "port is not ready %u\n", port); @@ -325,6 +329,8 @@ static ssize_t attach_store(struct device *dev, struct device_attribute *attr, if (!valid_args(pdev_nr, rhport, speed)) return -EINVAL; + pdev_nr = array_index_nospec(pdev_nr, vhci_num_controllers); + rhport = array_index_nospec(rhport, VHCI_HC_PORTS); hcd = platform_get_drvdata(vhcis[pdev_nr].pdev); if (hcd == NULL) { dev_err(dev, "port %d is not ready\n", port); -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
