HID: validate feature and input report details
When dealing with usage_index, be sure to properly use unsigned instead of
int to avoid overflows.
When working on report fields, always validate that their report_counts are
in bounds.
Without this, a HID device could report a malicious feature report that
could trick the driver into a heap overflow:
[ 634.885003] usb 1-1: New USB device found, idVendor=0596, idProduct=0500
...
[ 676.469629] BUG kmalloc-192 (Tainted: G W ): Redzone overwritten
CVE-2013-2897
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index be52c06..b8470b1 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -94,7 +94,6 @@
static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
{
struct hid_field *field;
- int i;
if (report->maxfield == HID_MAX_FIELDS) {
hid_err(report->device, "too many fields in report\n");
@@ -113,9 +112,6 @@
field->value = (s32 *)(field->usage + usages);
field->report = report;
- for (i = 0; i < usages; i++)
- field->usage[i].usage_index = i;
-
return field;
}
@@ -226,9 +222,9 @@
{
struct hid_report *report;
struct hid_field *field;
- int usages;
+ unsigned usages;
unsigned offset;
- int i;
+ unsigned i;
report = hid_register_report(parser->device, report_type, parser->global.report_id);
if (!report) {
@@ -255,7 +251,8 @@
if (!parser->local.usage_index) /* Ignore padding fields */
return 0;
- usages = max_t(int, parser->local.usage_index, parser->global.report_count);
+ usages = max_t(unsigned, parser->local.usage_index,
+ parser->global.report_count);
field = hid_register_field(report, usages, parser->global.report_count);
if (!field)
@@ -266,13 +263,14 @@
field->application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);
for (i = 0; i < usages; i++) {
- int j = i;
+ unsigned j = i;
/* Duplicate the last usage we parsed if we have excess values */
if (i >= parser->local.usage_index)
j = parser->local.usage_index - 1;
field->usage[i].hid = parser->local.usage[j];
field->usage[i].collection_index =
parser->local.collection_index[j];
+ field->usage[i].usage_index = i;
}
field->maxusage = usages;
@@ -1354,7 +1352,7 @@
goto out;
}
- if (hid->claimed != HID_CLAIMED_HIDRAW) {
+ if (hid->claimed != HID_CLAIMED_HIDRAW && report->maxfield) {
for (a = 0; a < report->maxfield; a++)
hid_input_field(hid, report->field[a], cdata, interrupt);
hdrv = hid->driver;