File 0021-usb-Avoid-possible-out-of-bound-accesses-caused-by-m.patch of Package grub2.19555
From b2329244be7fbd3e5404d9a0cfa56c4ce01086ec Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Fri, 11 Dec 2020 19:19:21 +0100
Subject: [PATCH 21/45] usb: Avoid possible out-of-bound accesses caused by
malicious devices
The maximum number of configurations and interfaces are fixed but there is
no out-of-bound checking to prevent a malicious USB device to report large
values for these and cause accesses outside the arrays' memory.
Fixes: CVE-2020-25647
Reported-by: Joseph Tartaro (IOActive)
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/bus/usb/usb.c | 15 ++++++++++++---
include/grub/usb.h | 10 +++++++---
2 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/grub-core/bus/usb/usb.c b/grub-core/bus/usb/usb.c
index 8da5e4c74..7cb3cc230 100644
--- a/grub-core/bus/usb/usb.c
+++ b/grub-core/bus/usb/usb.c
@@ -75,6 +75,9 @@ grub_usb_controller_iterate (grub_usb_controller_iterate_hook_t hook,
grub_usb_err_t
grub_usb_clear_halt (grub_usb_device_t dev, int endpoint)
{
+ if (endpoint >= GRUB_USB_MAX_TOGGLE)
+ return GRUB_USB_ERR_BADDEVICE;
+
dev->toggle[endpoint] = 0;
return grub_usb_control_msg (dev, (GRUB_USB_REQTYPE_OUT
| GRUB_USB_REQTYPE_STANDARD
@@ -134,10 +137,10 @@ grub_usb_device_initialize (grub_usb_device_t dev)
return err;
descdev = &dev->descdev;
- for (i = 0; i < 8; i++)
+ for (i = 0; i < GRUB_USB_MAX_CONF; i++)
dev->config[i].descconf = NULL;
- if (descdev->configcnt == 0)
+ if (descdev->configcnt == 0 || descdev->configcnt > GRUB_USB_MAX_CONF)
{
err = GRUB_USB_ERR_BADDEVICE;
goto fail;
@@ -172,6 +175,12 @@ grub_usb_device_initialize (grub_usb_device_t dev)
/* Skip the configuration descriptor. */
pos = dev->config[i].descconf->length;
+ if (dev->config[i].descconf->numif > GRUB_USB_MAX_IF)
+ {
+ err = GRUB_USB_ERR_BADDEVICE;
+ goto fail;
+ }
+
/* Read all interfaces. */
for (currif = 0; currif < dev->config[i].descconf->numif; currif++)
{
@@ -217,7 +226,7 @@ grub_usb_device_initialize (grub_usb_device_t dev)
fail:
- for (i = 0; i < 8; i++)
+ for (i = 0; i < GRUB_USB_MAX_CONF; i++)
grub_free (dev->config[i].descconf);
return err;
diff --git a/include/grub/usb.h b/include/grub/usb.h
index 512ae1dd0..6475c552f 100644
--- a/include/grub/usb.h
+++ b/include/grub/usb.h
@@ -23,6 +23,10 @@
#include <grub/usbdesc.h>
#include <grub/usbtrans.h>
+#define GRUB_USB_MAX_CONF 8
+#define GRUB_USB_MAX_IF 32
+#define GRUB_USB_MAX_TOGGLE 256
+
typedef struct grub_usb_device *grub_usb_device_t;
typedef struct grub_usb_controller *grub_usb_controller_t;
typedef struct grub_usb_controller_dev *grub_usb_controller_dev_t;
@@ -167,7 +171,7 @@ struct grub_usb_configuration
struct grub_usb_desc_config *descconf;
/* Interfaces associated to this configuration. */
- struct grub_usb_interface interf[32];
+ struct grub_usb_interface interf[GRUB_USB_MAX_IF];
};
struct grub_usb_hub_port
@@ -191,7 +195,7 @@ struct grub_usb_device
struct grub_usb_controller controller;
/* Device configurations (after opening the device). */
- struct grub_usb_configuration config[8];
+ struct grub_usb_configuration config[GRUB_USB_MAX_CONF];
/* Device address. */
int addr;
@@ -203,7 +207,7 @@ struct grub_usb_device
int initialized;
/* Data toggle values (used for bulk transfers only). */
- int toggle[256];
+ int toggle[GRUB_USB_MAX_TOGGLE];
/* Used by libusb wrapper. Schedulded for removal. */
void *data;
--
2.26.2