net: fib_rules: Use nlmsg_payload in fib_valid_dumprule_req

Leverage the new nlmsg_payload() helper to avoid checking for message
size and then reading the nlmsg data.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250414-nlmsg-v2-9-3d90cb42c6af@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 4bc64d9..6a7a28b 100644 (file)
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -1238,12 +1238,12 @@ static int fib_valid_dumprule_req(const struct nlmsghdr *nlh,
 {
        struct fib_rule_hdr *frh;
 
-       if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
+       frh = nlmsg_payload(nlh, sizeof(*frh));
+       if (!frh) {
                NL_SET_ERR_MSG(extack, "Invalid header for fib rule dump request");
                return -EINVAL;
        }
 
-       frh = nlmsg_data(nlh);
        if (frh->dst_len || frh->src_len || frh->tos || frh->table ||
            frh->res1 || frh->res2 || frh->action || frh->flags) {
                NL_SET_ERR_MSG(extack,