HID: hiddev: validate num_values for HIDIOCGUSAGES, HIDIOCSUSAGES commands (CVE-2016-5829)

debian/changelog

@@ -1,5 +1,6 @@
 linux (4.6.3-1) UNRELEASED; urgency=medium
 
+  [ Ben Hutchings ]
   * New upstream stable update:
     https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.6.3
     - scsi_lib: correctly retry failed zero length REQ_TYPE_FS commands
@@ -67,6 +68,10 @@ linux (4.6.3-1) UNRELEASED; urgency=medium
     - [x86] Revert "drm/i915: Exit cherryview_irq_handler() after one pass"
     - gpio: make sure gpiod_to_irq() returns negative on NULL desc
 
+  [ Salvatore Bonaccorso ]
+  * HID: hiddev: validate num_values for HIDIOCGUSAGES, HIDIOCSUSAGES commands
+    (CVE-2016-5829)
+
  -- Ben Hutchings <ben@decadent.org.uk>  Mon, 27 Jun 2016 00:31:11 +0200
 
 linux (4.6.2-2) unstable; urgency=medium

debian/patches/bugfix/all/HID-hiddev-validate-num_values-for-HIDIOCGUSAGES-HID.patch

@@ -0,0 +1,44 @@
+From: Scott Bauer <sbauer@plzdonthack.me>
+Date: Thu, 23 Jun 2016 08:59:47 -0600
+Subject: HID: hiddev: validate num_values for HIDIOCGUSAGES, HIDIOCSUSAGES
+ commands
+Origin: https://git.kernel.org/linus/93a2001bdfd5376c3dc2158653034c20392d15c5
+
+This patch validates the num_values parameter from userland during the
+HIDIOCGUSAGES and HIDIOCSUSAGES commands. Previously, if the report id was set
+to HID_REPORT_ID_UNKNOWN, we would fail to validate the num_values parameter
+leading to a heap overflow.
+
+Cc: stable@vger.kernel.org
+Signed-off-by: Scott Bauer <sbauer@plzdonthack.me>
+Signed-off-by: Jiri Kosina <jkosina@suse.cz>
+---
+ drivers/hid/usbhid/hiddev.c | 10 +++++-----
+ 1 file changed, 5 insertions(+), 5 deletions(-)
+
+diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c
+index 2f1ddca..700145b 100644
+--- a/drivers/hid/usbhid/hiddev.c
++++ b/drivers/hid/usbhid/hiddev.c
+@@ -516,13 +516,13 @@ static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd,
+ 					goto inval;
+ 			} else if (uref->usage_index >= field->report_count)
+ 				goto inval;
+-
+-			else if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
+-				 (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
+-				  uref->usage_index + uref_multi->num_values > field->report_count))
+-				goto inval;
+ 		}
+ 
++		if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
++		    (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
++		     uref->usage_index + uref_multi->num_values > field->report_count))
++			goto inval;
++
+ 		switch (cmd) {
+ 		case HIDIOCGUSAGE:
+ 			uref->value = field->value[uref->usage_index];
+-- 
+2.8.1
+

debian/patches/series

@@ -113,6 +113,7 @@ bugfix/all/percpu-fix-synchronization-between-chunk-map_extend_.patch
 bugfix/all/percpu-fix-synchronization-between-synchronous-map-e.patch
 bugfix/all/posix_acl-add-set_posix_acl.patch
 bugfix/all/nfsd-check-permissions-when-setting-acls.patch
+bugfix/all/HID-hiddev-validate-num_values-for-HIDIOCGUSAGES-HID.patch
 
 # ABI maintenance
 debian/mips-siginfo-fix-abi-change-in-4.6.2.patch