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>

diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index 0d3d3cc..7020247 100644 (file)
--- 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;

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 88afbae..115a08e 100644 (file)
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -908,6 +908,8 @@ fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
                        val = 65535 - 40;
                if (type == RTAX_MTU && val > 65535 - 15)
                        val = 65535 - 15;
+               if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
+                       return -EINVAL;
                fi->fib_metrics[type - 1] = val;
        }
 

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 0261b72..8771530 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1728,6 +1728,8 @@ static int ip6_convert_metrics(struct mx6_config *mxc,
                } else {
                        val = nla_get_u32(nla);
                }
+               if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
+                       goto err;
 
                mp[type - 1] = val;
                __set_bit(type - 1, mxc->mx_valid);