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From 84513107dc8602c675ec871b616128b49c6e259e Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Sat, 7 Oct 2017 11:07:47 -0700
Subject: Input: ims-psu - check if CDC union descriptor is sane
[ Upstream commit ea04efee7635c9120d015dcdeeeb6988130cb67a ]
Before trying to use CDC union descriptor, try to validate whether that it
is sane by checking that intf->altsetting->extra is big enough and that
descriptor bLength is not too big and not too small.
Upstream-Status: Backport [https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/drivers/input/misc/ims-pcu.c?h=linux-4.1.y&id=84513107dc8602c675ec871b616128b49c6e259e]
CVE: CVE-2017-16645
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Adrian Stratulat <adrian.stratulat@enea.com>
---
drivers/input/misc/ims-pcu.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
(limited to 'drivers/input/misc/ims-pcu.c')
diff --git a/drivers/input/misc/ims-pcu.c b/drivers/input/misc/ims-pcu.c
index f4e8fbec6a94..b5304e264881 100644
--- a/drivers/input/misc/ims-pcu.c
+++ b/drivers/input/misc/ims-pcu.c
@@ -1635,13 +1635,25 @@ ims_pcu_get_cdc_union_desc(struct usb_interface *intf)
return NULL;
}
- while (buflen > 0) {
+ while (buflen >= sizeof(*union_desc)) {
union_desc = (struct usb_cdc_union_desc *)buf;
+ if (union_desc->bLength > buflen) {
+ dev_err(&intf->dev, "Too large descriptor\n");
+ return NULL;
+ }
+
if (union_desc->bDescriptorType == USB_DT_CS_INTERFACE &&
union_desc->bDescriptorSubType == USB_CDC_UNION_TYPE) {
dev_dbg(&intf->dev, "Found union header\n");
- return union_desc;
+
+ if (union_desc->bLength >= sizeof(*union_desc))
+ return union_desc;
+
+ dev_err(&intf->dev,
+ "Union descriptor to short (%d vs %zd\n)",
+ union_desc->bLength, sizeof(*union_desc));
+ return NULL;
}
buflen -= union_desc->bLength;
--
cgit 1.2-0.3.lf.el7
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