From 128c16a682034263eb519c89bc0934eeb6fa8cfa Mon Sep 17 00:00:00 2001 From: Javier Martinez Canillas Date: Fri, 11 Dec 2020 19:19:21 +0100 Subject: [PATCH] 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 Reported-by: Ilja Van Sprundel Signed-off-by: Javier Martinez Canillas Reviewed-by: Daniel Kiper Signed-off-by: Stefan Sørensen --- 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 8da5e4c..7cb3cc2 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 512ae1d..6475c55 100644 --- a/include/grub/usb.h +++ b/include/grub/usb.h @@ -23,6 +23,10 @@ #include #include +#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; -- 2.14.2