[PATCH nft] datatype: do not assert when value exceeds 255

[Florian Westphal <fw@strlen.de>]

Before:
nft list ruleset
chain c {
   ip protocol & nft: src/gmputil.c:77: mpz_get_uint8: Assertion `cnt <= 1' failed.
Aborted (core dumped)

After:
table ip t {
        chain c {
                ip protocol & 18446739675663040512 . th dport 0 . 0
	}
}

Note that nft should not have allowed to add such rule in the first
place, input is:

ip protocol . th dport { tcp / 22,  }'

... which should be rejected, but is currently allowed.
The decoding is incorrect too (as seen by 0 . 0).

But technically a 'direct nfnetlink user' could create this too
and decoding should work in all cases.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 src/datatype.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/datatype.c b/src/datatype.c
index 86d55a524269..5abfd978a39b 100644
--- a/src/datatype.c
+++ b/src/datatype.c
@@ -715,7 +715,8 @@ const struct datatype ip6addr_type = {
 static void inet_protocol_type_print(const struct expr *expr,
 				      struct output_ctx *octx)
 {
-	if (!nft_output_numeric_proto(octx)) {
+	if (!nft_output_numeric_proto(octx) &&
+	    mpz_cmp_ui(expr->value, UINT_MAX) <= 0) {
 		char name[NFT_PROTONAME_MAXSIZE];
 
 		if (nft_getprotobynumber(mpz_get_uint8(expr->value), name, sizeof(name))) {
-- 
2.41.0