bpf: Verify flags in bpf_fib_lookup

Verify flags argument contains only known flags. Allows programs to probe
for support as more are added.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/net/core/filter.c b/net/core/filter.c
index 0ce93ed..81bd2e9 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4270,6 +4270,9 @@ BPF_CALL_4(bpf_xdp_fib_lookup, struct xdp_buff *, ctx,
        if (plen < sizeof(*params))
                return -EINVAL;
 
+       if (flags & ~(BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_OUTPUT))
+               return -EINVAL;
+
        switch (params->family) {
 #if IS_ENABLED(CONFIG_INET)
        case AF_INET:
@@ -4304,6 +4307,9 @@ BPF_CALL_4(bpf_skb_fib_lookup, struct sk_buff *, skb,
        if (plen < sizeof(*params))
                return -EINVAL;
 
+       if (flags & ~(BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_OUTPUT))
+               return -EINVAL;
+
        switch (params->family) {
 #if IS_ENABLED(CONFIG_INET)
        case AF_INET: