[v2.6.34-stable 018/213] HID: pantherlord: validate output report details

[Paul Gortmaker]

From: Kees Cook <keescook@xxxxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit 412f30105ec6735224535791eed5cdc02888ecb4 upstream.

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@xxxxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 drivers/hid/hid-pl.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-pl.c b/drivers/hid/hid-pl.c
index 9f41e2bd8483..427f3a57aa23 100644
--- a/drivers/hid/hid-pl.c
+++ b/drivers/hid/hid-pl.c
@@ -129,8 +129,14 @@ 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];
-- 
1.8.5.2

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