This is a note to let you know that I've just added the patch titled
USB: fix out-of-bounds in usb_set_configuration
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From bd7a3fe770ebd8391d1c7d072ff88e9e76d063eb Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Date: Tue, 19 Sep 2017 15:07:17 +0200
Subject: USB: fix out-of-bounds in usb_set_configuration
Andrey Konovalov reported a possible out-of-bounds problem for a USB interface
association descriptor. He writes:
It seems there's no proper size check of a USB_DT_INTERFACE_ASSOCIATION
descriptor. It's only checked that the size is >= 2 in
usb_parse_configuration(), so find_iad() might do out-of-bounds access
to intf_assoc->bInterfaceCount.
And he's right, we don't check for crazy descriptors of this type very well, so
resolve this problem. Yet another issue found by syzkaller...
Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Tested-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/core/config.c | 14 +++++++++++---
include/uapi/linux/usb/ch9.h | 1 +
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 854c8d66cfbe..68b54bd88d1e 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -643,15 +643,23 @@ static int usb_parse_configuration(struct usb_device *dev, int cfgidx,
} else if (header->bDescriptorType ==
USB_DT_INTERFACE_ASSOCIATION) {
+ struct usb_interface_assoc_descriptor *d;
+
+ d = (struct usb_interface_assoc_descriptor *)header;
+ if (d->bLength < USB_DT_INTERFACE_ASSOCIATION_SIZE) {
+ dev_warn(ddev,
+ "config %d has an invalid interface association descriptor of length %d, skipping\n",
+ cfgno, d->bLength);
+ continue;
+ }
+
if (iad_num == USB_MAXIADS) {
dev_warn(ddev, "found more Interface "
"Association Descriptors "
"than allocated for in "
"configuration %d\n", cfgno);
} else {
- config->intf_assoc[iad_num] =
- (struct usb_interface_assoc_descriptor
- *)header;
+ config->intf_assoc[iad_num] = d;
iad_num++;
}
diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h
index ce1169af39d7..2a5d63040a0b 100644
--- a/include/uapi/linux/usb/ch9.h
+++ b/include/uapi/linux/usb/ch9.h
@@ -780,6 +780,7 @@ struct usb_interface_assoc_descriptor {
__u8 iFunction;
} __attribute__ ((packed));
+#define USB_DT_INTERFACE_ASSOCIATION_SIZE 8
/*-------------------------------------------------------------------------*/
--
2.14.1