[PATCH 4.4 13/52] net: ieee802154: handle iftypes as u32

From: Alexander Aring <aahringo@redhat.com>

[ Upstream commit 451dc48c806a7ce9fbec5e7a24ccf4b2c936e834 ]

This patch fixes an issue that an u32 netlink value is handled as a
signed enum value which doesn't fit into the range of u32 netlink type.
If it's handled as -1 value some BIT() evaluation ends in a
shift-out-of-bounds issue. To solve the issue we set the to u32 max which
is s32 "-1" value to keep backwards compatibility and let the followed enum
values start counting at 0. This brings the compiler to never handle the
enum as signed and a check if the value is above NL802154_IFTYPE_MAX should
filter -1 out.

Fixes: f3ea5e44231a ("ieee802154: add new interface command")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20211112030916.685793-1-aahringo@redhat.com (local)
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/net/nl802154.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/net/nl802154.h b/include/net/nl802154.h
index 32cb3e591e07b..53f140fc1983c 100644
--- a/include/net/nl802154.h
+++ b/include/net/nl802154.h

@@ -19,6 +19,8 @@
  *
  */
 
+#include <linux/types.h>
+
 #define NL802154_GENL_NAME "nl802154"
 
 enum nl802154_commands {

@@ -143,10 +145,9 @@ enum nl802154_attrs {
 };
 
 enum nl802154_iftype {
-	/* for backwards compatibility TODO */
-	NL802154_IFTYPE_UNSPEC = -1,
+	NL802154_IFTYPE_UNSPEC = (~(__u32)0),
 
-	NL802154_IFTYPE_NODE,
+	NL802154_IFTYPE_NODE = 0,
 	NL802154_IFTYPE_MONITOR,
 	NL802154_IFTYPE_COORD,
 

-- 
2.33.0