3.2.52-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
commit cc6b54aa54bf40b762cab45a9fc8aa81653146eb upstream.
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
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
[bwh: Backported to 3.2:
- Drop inapplicable changes to hid_usage::usage_index initialisation and
to hid_report_raw_event()
- Adjust context in report_features()
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -218,9 +218,9 @@ static int hid_add_field(struct hid_pars
{
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) {
@@ -239,7 +239,8 @@ static int hid_add_field(struct hid_pars
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)
@@ -250,7 +251,7 @@ static int hid_add_field(struct hid_pars
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;
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -284,6 +284,10 @@ static void hidinput_configure_usage(str
if (field->flags & HID_MAIN_ITEM_CONSTANT)
goto ignore;
+ /* Ignore if report count is out of bounds. */
+ if (field->report_count < 1)
+ goto ignore;
+
/* only LED usages are supported in output fields */
if (field->report_type == HID_OUTPUT_REPORT &&
(usage->hid & HID_USAGE_PAGE) != HID_UP_LED) {
@@ -887,10 +891,15 @@ static void report_features(struct hid_d
rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
list_for_each_entry(rep, &rep_enum->report_list, list)
- for (i = 0; i < rep->maxfield; i++)
+ for (i = 0; i < rep->maxfield; i++) {
+ /* Ignore if report count is out of bounds. */
+ if (rep->field[i]->report_count < 1)
+ continue;
+
for (j = 0; j < rep->field[i]->maxusage; j++)
drv->feature_mapping(hid, rep->field[i],
rep->field[i]->usage + j);
+ }
}
/*
--
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