| From 43622021d2e2b82ea03d883926605bdd0525e1d1 Mon Sep 17 00:00:00 2001 |
| From: Kees Cook <keescook@chromium.org> |
| Date: Wed, 28 Aug 2013 22:29:55 +0200 |
| Subject: HID: validate HID report id size |
| |
| From: Kees Cook <keescook@chromium.org> |
| |
| commit 43622021d2e2b82ea03d883926605bdd0525e1d1 upstream. |
| |
| The "Report ID" field of a HID report is used to build indexes of |
| reports. The kernel's index of these is limited to 256 entries, so any |
| malicious device that sets a Report ID greater than 255 will trigger |
| memory corruption on the host: |
| |
| [ 1347.156239] BUG: unable to handle kernel paging request at ffff88094958a878 |
| [ 1347.156261] IP: [<ffffffff813e4da0>] hid_register_report+0x2a/0x8b |
| |
| CVE-2013-2888 |
| |
| Signed-off-by: Kees Cook <keescook@chromium.org> |
| Signed-off-by: Jiri Kosina <jkosina@suse.cz> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/hid/hid-core.c | 10 +++++++--- |
| include/linux/hid.h | 4 +++- |
| 2 files changed, 10 insertions(+), 4 deletions(-) |
| |
| --- a/drivers/hid/hid-core.c |
| +++ b/drivers/hid/hid-core.c |
| @@ -63,6 +63,8 @@ struct hid_report *hid_register_report(s |
| struct hid_report_enum *report_enum = device->report_enum + type; |
| struct hid_report *report; |
| |
| + if (id >= HID_MAX_IDS) |
| + return NULL; |
| if (report_enum->report_id_hash[id]) |
| return report_enum->report_id_hash[id]; |
| |
| @@ -404,8 +406,10 @@ static int hid_parser_global(struct hid_ |
| |
| case HID_GLOBAL_ITEM_TAG_REPORT_ID: |
| parser->global.report_id = item_udata(item); |
| - if (parser->global.report_id == 0) { |
| - hid_err(parser->device, "report_id 0 is invalid\n"); |
| + if (parser->global.report_id == 0 || |
| + parser->global.report_id >= HID_MAX_IDS) { |
| + hid_err(parser->device, "report_id %u is invalid\n", |
| + parser->global.report_id); |
| return -1; |
| } |
| return 0; |
| @@ -575,7 +579,7 @@ static void hid_close_report(struct hid_ |
| for (i = 0; i < HID_REPORT_TYPES; i++) { |
| struct hid_report_enum *report_enum = device->report_enum + i; |
| |
| - for (j = 0; j < 256; j++) { |
| + for (j = 0; j < HID_MAX_IDS; j++) { |
| struct hid_report *report = report_enum->report_id_hash[j]; |
| if (report) |
| hid_free_report(report); |
| --- a/include/linux/hid.h |
| +++ b/include/linux/hid.h |
| @@ -393,10 +393,12 @@ struct hid_report { |
| struct hid_device *device; /* associated device */ |
| }; |
| |
| +#define HID_MAX_IDS 256 |
| + |
| struct hid_report_enum { |
| unsigned numbered; |
| struct list_head report_list; |
| - struct hid_report *report_id_hash[256]; |
| + struct hid_report *report_id_hash[HID_MAX_IDS]; |
| }; |
| |
| #define HID_REPORT_TYPES 3 |