This is a note to let you know that I've just added the patch titled
usb: gadget: storage: Fix Spectre v1 vulnerability
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-gadget-storage-fix-spectre-v1-vulnerability.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9ae24af3669111d418242caec8dd4ebd9ba26860 Mon Sep 17 00:00:00 2001
From: "Gustavo A. R. Silva" <gustavo@xxxxxxxxxxxxxx>
Date: Tue, 16 Oct 2018 12:16:45 +0200
Subject: usb: gadget: storage: Fix Spectre v1 vulnerability
From: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
commit 9ae24af3669111d418242caec8dd4ebd9ba26860 upstream.
num 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/usb/gadget/function/f_mass_storage.c:3177 fsg_lun_make() warn:
potential spectre issue 'fsg_opts->common->luns' [r] (local cap)
Fix this by sanitizing num before using it to index
fsg_opts->common->luns
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>
Acked-by: Felipe Balbi <felipe.balbi@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/function/f_mass_storage.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -220,6 +220,8 @@
#include <linux/usb/gadget.h>
#include <linux/usb/composite.h>
+#include <linux/nospec.h>
+
#include "configfs.h"
@@ -3260,6 +3262,7 @@ static struct config_group *fsg_lun_make
fsg_opts = to_fsg_opts(&group->cg_item);
if (num >= FSG_MAX_LUNS)
return ERR_PTR(-ERANGE);
+ num = array_index_nospec(num, FSG_MAX_LUNS);
mutex_lock(&fsg_opts->lock);
if (fsg_opts->refcnt || fsg_opts->common->luns[num]) {
Patches currently in stable-queue which might be from gustavo@xxxxxxxxxxxxxx are
queue-4.4/video-fbdev-pxa3xx_gcu-fix-error-return-code-in-pxa3.patch
queue-4.4/spi-bcm63xx-fix-error-return-code-in-bcm63xx_spi_pro.patch
queue-4.4/usb-imx21-hcd-fix-error-return-code-in-imx21_probe.patch
queue-4.4/spi-xlp-fix-error-return-code-in-xlp_spi_probe.patch
queue-4.4/gpio-msic-fix-error-return-code-in-platform_msic_gpi.patch
queue-4.4/usb-ehci-omap-fix-error-return-code-in-ehci_hcd_omap.patch
queue-4.4/gpu-host1x-fix-error-return-code-in-host1x_probe.patch
queue-4.4/ptp-fix-spectre-v1-vulnerability.patch
queue-4.4/tty-serial-sprd-fix-error-return-code-in-sprd_probe.patch
queue-4.4/rdma-ucma-fix-spectre-v1-vulnerability.patch
queue-4.4/usb-gadget-storage-fix-spectre-v1-vulnerability.patch
queue-4.4/ib-ucm-fix-spectre-v1-vulnerability.patch
queue-4.4/usb-dwc3-omap-fix-error-return-code-in-dwc3_omap_pro.patch
queue-4.4/spi-bcm63xx-hspi-fix-error-return-code-in-bcm63xx_hs.patch
