From cc6b54aa54bf40b762cab45a9fc8aa81653146eb Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Wed, 11 Sep 2013 21:56:57 +0200 Subject: [PATCH] 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 Acked-by: Kees Cook Signed-off-by: Jiri Kosina --- drivers/hid/hid-core.c | 16 +++++++--------- drivers/hid/hid-input.c | 11 ++++++++++- 2 files changed, 17 insertions(+), 10 deletions(-) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index be52c06dbe30..b8470b1a10fe 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -94,7 +94,6 @@ EXPORT_SYMBOL_GPL(hid_register_report); 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 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned 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 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign { 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 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign 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 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign 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 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, int size, 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; diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index b420f4a0fd28..8741d953dcc8 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -485,6 +485,10 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel 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) { @@ -1236,7 +1240,11 @@ static void report_features(struct hid_device *hid) 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++) { /* Verify if Battery Strength feature is available */ hidinput_setup_battery(hid, HID_FEATURE_REPORT, rep->field[i]); @@ -1245,6 +1253,7 @@ static void report_features(struct hid_device *hid) drv->feature_mapping(hid, rep->field[i], rep->field[i]->usage + j); } + } } static struct hid_input *hidinput_allocate(struct hid_device *hid) -- 2.39.5