fib, fib6: reject invalid feature bits

Feature bits that are invalid should not be accepted by the kernel,
only the lower 4 bits may be configured, but not the remaining ones.
Even from these 4, 2 of them are unused.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 4 deletions

diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index 0d3d3cc43356..702024769c74 100644
--- a/include/uapi/linux/rtnetlink.h
+++ b/include/uapi/linux/rtnetlink.h
@@ -418,10 +418,13 @@ enum {
 
 #define RTAX_MAX (__RTAX_MAX - 1)
 
-#define RTAX_FEATURE_ECN        0x00000001
-#define RTAX_FEATURE_SACK       0x00000002
-#define RTAX_FEATURE_TIMESTAMP  0x00000004
-#define RTAX_FEATURE_ALLFRAG    0x00000008
+#define RTAX_FEATURE_ECN        (1 << 0)
+#define RTAX_FEATURE_SACK       (1 << 1)
+#define RTAX_FEATURE_TIMESTAMP  (1 << 2)
+#define RTAX_FEATURE_ALLFRAG    (1 << 3)
+
+#define RTAX_FEATURE_MASK       (RTAX_FEATURE_ECN | RTAX_FEATURE_SACK | \
+                                 RTAX_FEATURE_TIMESTAMP | RTAX_FEATURE_ALLFRAG)
 
 struct rta_session {
         __u8    proto;