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usb: Avoid possible out-of-bound accesses caused by malicious devices

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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 <joseph.tartaro@ioactive.com>
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>
This commit is contained in:
Javier Martinez Canillas 2020-12-11 19:19:21 +01:00 committed by Daniel Kiper
parent 7630ec5397
commit 128c16a682
2 changed files with 19 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
grub-core/bus/usb/usb.c
View File

@ -75,6 +75,9 @@ grub_usb_controller_iterate (grub_usb_controller_iterate_hook_t hook,
grub_usb_err_t grub_usb_err_t
grub_usb_clear_halt (grub_usb_device_t dev, int endpoint) 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; dev->toggle[endpoint] = 0;
return grub_usb_control_msg (dev, (GRUB_USB_REQTYPE_OUT return grub_usb_control_msg (dev, (GRUB_USB_REQTYPE_OUT
| GRUB_USB_REQTYPE_STANDARD | GRUB_USB_REQTYPE_STANDARD
@ -134,10 +137,10 @@ grub_usb_device_initialize (grub_usb_device_t dev)
return err; return err;
descdev = &dev->descdev; descdev = &dev->descdev;
for (i = 0; i < 8; i++) for (i = 0; i < GRUB_USB_MAX_CONF; i++)
dev->config[i].descconf = NULL; dev->config[i].descconf = NULL;
if (descdev->configcnt == 0) if (descdev->configcnt == 0 || descdev->configcnt > GRUB_USB_MAX_CONF)
{ {
err = GRUB_USB_ERR_BADDEVICE; err = GRUB_USB_ERR_BADDEVICE;
goto fail; goto fail;
@ -172,6 +175,12 @@ grub_usb_device_initialize (grub_usb_device_t dev)
/* Skip the configuration descriptor. */ /* Skip the configuration descriptor. */
pos = dev->config[i].descconf->length; 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. */ /* Read all interfaces. */
for (currif = 0; currif < dev->config[i].descconf->numif; currif++) for (currif = 0; currif < dev->config[i].descconf->numif; currif++)
{ {
@ -217,7 +226,7 @@ grub_usb_device_initialize (grub_usb_device_t dev)
fail: fail:
for (i = 0; i < 8; i++) for (i = 0; i < GRUB_USB_MAX_CONF; i++)
grub_free (dev->config[i].descconf); grub_free (dev->config[i].descconf);
return err; return err;

10
include/grub/usb.h
View File

@ -23,6 +23,10 @@
#include <grub/usbdesc.h> #include <grub/usbdesc.h>
#include <grub/usbtrans.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_device *grub_usb_device_t;
typedef struct grub_usb_controller *grub_usb_controller_t; typedef struct grub_usb_controller *grub_usb_controller_t;
typedef struct grub_usb_controller_dev *grub_usb_controller_dev_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; struct grub_usb_desc_config *descconf;
/* Interfaces associated to this configuration. */ /* 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 struct grub_usb_hub_port
@ -191,7 +195,7 @@ struct grub_usb_device
struct grub_usb_controller controller; struct grub_usb_controller controller;
/* Device configurations (after opening the device). */ /* Device configurations (after opening the device). */
struct grub_usb_configuration config[8]; struct grub_usb_configuration config[GRUB_USB_MAX_CONF];
/* Device address. */ /* Device address. */
int addr; int addr;
@ -203,7 +207,7 @@ struct grub_usb_device
int initialized; int initialized;
/* Data toggle values (used for bulk transfers only). */ /* Data toggle values (used for bulk transfers only). */
int toggle[256]; int toggle[GRUB_USB_MAX_TOGGLE];
/* Used by libusb wrapper. Schedulded for removal. */ /* Used by libusb wrapper. Schedulded for removal. */
void *data; void *data;