HID: pantherlord: validate output report details

A HID device could send a malicious output report that would cause the
pantherlord HID driver to write beyond the output report allocation
during initialization, causing a heap overflow:

[  310.939483] usb 1-1: New USB device found, idVendor=0e8f, idProduct=0003
...
[  315.980774] BUG kmalloc-192 (Tainted: G        W   ): Redzone overwritten

CVE-2013-2892

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@kernel.org
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/hid/hid-pl.c b/drivers/hid/hid-pl.c
index d29112fa5cd5..2dcd7d98dbd6 100644
--- a/drivers/hid/hid-pl.c
+++ b/drivers/hid/hid-pl.c
@@ -132,8 +132,14 @@ static int plff_init(struct hid_device *hid)
                         strong = &report->field[0]->value[2];
                         weak = &report->field[0]->value[3];
                         debug("detected single-field device");
-                } else if (report->maxfield >= 4 && report->field[0]->maxusage == 1 &&
-                                report->field[0]->usage[0].hid == (HID_UP_LED | 0x43)) {
+                } else if (report->field[0]->maxusage == 1 &&
+                           report->field[0]->usage[0].hid ==
+                                (HID_UP_LED | 0x43) &&
+                           report->maxfield >= 4 &&
+                           report->field[0]->report_count >= 1 &&
+                           report->field[1]->report_count >= 1 &&
+                           report->field[2]->report_count >= 1 &&
+                           report->field[3]->report_count >= 1) {
                         report->field[0]->value[0] = 0x00;
                         report->field[1]->value[0] = 0x00;
                         strong = &report->field[2]->value[0];