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usb: Use well-known descriptor sizes when parsing configuration

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The existing USB configuration parsing code relies on the descriptors'
own length values when reading through the configuration blob. Since the
size of those descriptors is always well-defined, we should rather use
the known sizes instead of trusting device-provided values to be
correct. Also adds some safety to potential out-of-order descriptors.

Change-Id: I16f69dfdd6793aa0fe930b5148d4521f3e5c3090
Signed-off-by: Julius Werner <jwerner@chromium.org>
master
Julius Werner 11 years ago committed by Marek Vasut
parent 1572eadfbc
commit eaf3e613ea
2 changed files with 75 additions and 26 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 87
      common/usb.c
  2. 14
      common/usb_hub.c

87
common/usb.c
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@ -323,6 +323,7 @@ static int usb_set_maxpacket(struct usb_device *dev)
/*******************************************************************************
* Parse the config, located in buffer, and fills the dev->config structure.
* Note that all little/big endian swapping are done automatically.
* (wTotalLength has already been swapped and sanitized when it was read.)
*/
static int usb_parse_config(struct usb_device *dev,
unsigned char *buffer, int cfgno)
@ -343,24 +344,43 @@ static int usb_parse_config(struct usb_device *dev,
head->bDescriptorType);
return -1;
}
memcpy(&dev->config, buffer, buffer[0]);
le16_to_cpus(&(dev->config.desc.wTotalLength));
if (head->bLength != USB_DT_CONFIG_SIZE) {
printf("ERROR: Invalid USB CFG length (%d)\n", head->bLength);
return -1;
}
memcpy(&dev->config, head, USB_DT_CONFIG_SIZE);
dev->config.no_of_if = 0;
index = dev->config.desc.bLength;
/* Ok the first entry must be a configuration entry,
* now process the others */
head = (struct usb_descriptor_header *) &buffer[index];
while (index + 1 < dev->config.desc.wTotalLength) {
while (index + 1 < dev->config.desc.wTotalLength && head->bLength) {
switch (head->bDescriptorType) {
case USB_DT_INTERFACE:
if (head->bLength != USB_DT_INTERFACE_SIZE) {
printf("ERROR: Invalid USB IF length (%d)\n",
head->bLength);
break;
}
if (index + USB_DT_INTERFACE_SIZE >
dev->config.desc.wTotalLength) {
puts("USB IF descriptor overflowed buffer!\n");
break;
}
if (((struct usb_interface_descriptor *) \
&buffer[index])->bInterfaceNumber != curr_if_num) {
head)->bInterfaceNumber != curr_if_num) {
/* this is a new interface, copy new desc */
ifno = dev->config.no_of_if;
if (ifno >= USB_MAXINTERFACES) {
puts("Too many USB interfaces!\n");
/* try to go on with what we have */
return 1;
}
if_desc = &dev->config.if_desc[ifno];
dev->config.no_of_if++;
memcpy(if_desc, &buffer[index], buffer[index]);
memcpy(if_desc, head,
USB_DT_INTERFACE_SIZE);
if_desc->no_of_ep = 0;
if_desc->num_altsetting = 1;
curr_if_num =
@ -374,12 +394,31 @@ static int usb_parse_config(struct usb_device *dev,
}
break;
case USB_DT_ENDPOINT:
if (head->bLength != USB_DT_ENDPOINT_SIZE) {
printf("ERROR: Invalid USB EP length (%d)\n",
head->bLength);
break;
}
if (index + USB_DT_ENDPOINT_SIZE >
dev->config.desc.wTotalLength) {
puts("USB EP descriptor overflowed buffer!\n");
break;
}
if (ifno < 0) {
puts("Endpoint descriptor out of order!\n");
break;
}
epno = dev->config.if_desc[ifno].no_of_ep;
if_desc = &dev->config.if_desc[ifno];
if (epno > USB_MAXENDPOINTS) {
printf("Interface %d has too many endpoints!\n",
if_desc->desc.bInterfaceNumber);
return 1;
}
/* found an endpoint */
if_desc->no_of_ep++;
memcpy(&if_desc->ep_desc[epno],
&buffer[index], buffer[index]);
memcpy(&if_desc->ep_desc[epno], head,
USB_DT_ENDPOINT_SIZE);
ep_wMaxPacketSize = get_unaligned(&dev->config.\
if_desc[ifno].\
ep_desc[epno].\
@ -392,9 +431,23 @@ static int usb_parse_config(struct usb_device *dev,
debug("if %d, ep %d\n", ifno, epno);
break;
case USB_DT_SS_ENDPOINT_COMP:
if (head->bLength != USB_DT_SS_EP_COMP_SIZE) {
printf("ERROR: Invalid USB EPC length (%d)\n",
head->bLength);
break;
}
if (index + USB_DT_SS_EP_COMP_SIZE >
dev->config.desc.wTotalLength) {
puts("USB EPC descriptor overflowed buffer!\n");
break;
}
if (ifno < 0 || epno < 0) {
puts("EPC descriptor out of order!\n");
break;
}
if_desc = &dev->config.if_desc[ifno];
memcpy(&if_desc->ss_ep_comp_desc[epno],
&buffer[index], buffer[index]);
memcpy(&if_desc->ss_ep_comp_desc[epno], head,
USB_DT_SS_EP_COMP_SIZE);
break;
default:
if (head->bLength == 0)
@ -473,7 +526,7 @@ int usb_get_configuration_no(struct usb_device *dev,
unsigned char *buffer, int cfgno)
{
int result;
unsigned int tmp;
unsigned int length;
struct usb_config_descriptor *config;
config = (struct usb_config_descriptor *)&buffer[0];
@ -487,16 +540,18 @@ int usb_get_configuration_no(struct usb_device *dev,
"(expected %i, got %i)\n", 9, result);
return -1;
}
tmp = le16_to_cpu(config->wTotalLength);
length = le16_to_cpu(config->wTotalLength);
if (tmp > USB_BUFSIZ) {
printf("usb_get_configuration_no: failed to get " \
"descriptor - too long: %d\n", tmp);
if (length > USB_BUFSIZ) {
printf("%s: failed to get descriptor - too long: %d\n",
__func__, length);
return -1;
}
result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno, buffer, tmp);
debug("get_conf_no %d Result %d, wLength %d\n", cfgno, result, tmp);
result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno, buffer, length);
debug("get_conf_no %d Result %d, wLength %d\n", cfgno, result, length);
config->wTotalLength = length; /* validated, with CPU byte order */
return result;
}

14
common/usb_hub.c
Unescape View File

@ -306,7 +306,7 @@ void usb_hub_port_connect_change(struct usb_device *dev, int port)
static int usb_hub_configure(struct usb_device *dev)
{
int i;
int i, length;
ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, USB_BUFSIZ);
unsigned char *bitmap;
short hubCharacteristics;
@ -327,20 +327,14 @@ static int usb_hub_configure(struct usb_device *dev)
}
descriptor = (struct usb_hub_descriptor *)buffer;
/* silence compiler warning if USB_BUFSIZ is > 256 [= sizeof(char)] */
i = descriptor->bLength;
if (i > USB_BUFSIZ) {
debug("usb_hub_configure: failed to get hub " \
"descriptor - too long: %d\n", descriptor->bLength);
return -1;
}
length = min(descriptor->bLength, sizeof(struct usb_hub_descriptor));
if (usb_get_hub_descriptor(dev, buffer, descriptor->bLength) < 0) {
if (usb_get_hub_descriptor(dev, buffer, length) < 0) {
debug("usb_hub_configure: failed to get hub " \
"descriptor 2nd giving up %lX\n", dev->status);
return -1;
}
memcpy((unsigned char *)&hub->desc, buffer, descriptor->bLength);
memcpy((unsigned char *)&hub->desc, buffer, length);
/* adjust 16bit values */
put_unaligned(le16_to_cpu(get_unaligned(
&descriptor->wHubCharacteristics)),

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