Its possible to end up with prefix expressions that have a symbolic expression, e.g.: table t { set s { type inet_service flags interval elements = { 0-1024, 8080-8082, 10000-40000 } elements = { 172.16.0.0/16 } } set s { type inet_service flags interval elements = { 0-1024, 8080-8082, 10000-40000 } } } Without this change, nft will crash. We end up in setelem_expr_to_range() with prefix "/16" for the symbolic expression "172.16.0.0". We than pass invalid mpz_t pointer into libgmp. This isn't the right fix (see next patch), but instead of blindly assuming that the attached expression has a gmp value die with at least some info. Its possible there are more ways than one to feed such "symbol-with-prefix" down into the interval code, so also add this assertion. Signed-off-by: Florian Westphal <fw@xxxxxxxxx> --- src/intervals.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/intervals.c b/src/intervals.c index 85de0199c373..6849b221df2c 100644 --- a/src/intervals.c +++ b/src/intervals.c @@ -26,6 +26,9 @@ static void setelem_expr_to_range(struct expr *expr) case EXPR_RANGE: break; case EXPR_PREFIX: + if (expr->key->prefix->etype != EXPR_VALUE) + BUG("Prefix for unexpected type %d", expr->key->prefix->etype); + mpz_init(rop); mpz_bitmask(rop, expr->key->len - expr->key->prefix_len); if (expr_basetype(expr)->type == TYPE_STRING) -- 2.41.0