net: Use nlmsg_payload in rtnetlink file

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/20250417-nlmsg_v3-v1-2-9b09d9d7e61d@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index ea2e15de8d997407bb7c18728ad39f2cf279ad93..8a914b37ef6e88b18e7d13c33c74eb3fadf975d3 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2390,12 +2390,12 @@ static int rtnl_valid_dump_ifinfo_req(const struct nlmsghdr *nlh,
        if (strict_check) {
                struct ifinfomsg *ifm;
 
-               if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifm))) {
+               ifm = nlmsg_payload(nlh, sizeof(*ifm));
+               if (!ifm) {
                        NL_SET_ERR_MSG(extack, "Invalid header for link dump");
                        return -EINVAL;
                }
 
-               ifm = nlmsg_data(nlh);
                if (ifm->__ifi_pad || ifm->ifi_type || ifm->ifi_flags ||
                    ifm->ifi_change) {
                        NL_SET_ERR_MSG(extack, "Invalid values in header for link dump request");
@@ -4084,7 +4084,8 @@ static int rtnl_valid_getlink_req(struct sk_buff *skb,
        struct ifinfomsg *ifm;
        int i, err;
 
-       if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifm))) {
+       ifm = nlmsg_payload(nlh, sizeof(*ifm));
+       if (!ifm) {
                NL_SET_ERR_MSG(extack, "Invalid header for get link");
                return -EINVAL;
        }
@@ -4093,7 +4094,6 @@ static int rtnl_valid_getlink_req(struct sk_buff *skb,
                return nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFLA_MAX,
                                              ifla_policy, extack);
 
-       ifm = nlmsg_data(nlh);
        if (ifm->__ifi_pad || ifm->ifi_type || ifm->ifi_flags ||
            ifm->ifi_change) {
                NL_SET_ERR_MSG(extack, "Invalid values in header for get link request");
@@ -5052,12 +5052,12 @@ static int valid_fdb_get_strict(const struct nlmsghdr *nlh,
        struct ndmsg *ndm;
        int err, i;
 
-       if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ndm))) {
+       ndm = nlmsg_payload(nlh, sizeof(*ndm));
+       if (!ndm) {
                NL_SET_ERR_MSG(extack, "Invalid header for fdb get request");
                return -EINVAL;
        }
 
-       ndm = nlmsg_data(nlh);
        if (ndm->ndm_pad1  || ndm->ndm_pad2  || ndm->ndm_state ||
            ndm->ndm_type) {
                NL_SET_ERR_MSG(extack, "Invalid values in header for fdb get request");
@@ -5324,12 +5324,12 @@ static int valid_bridge_getlink_req(const struct nlmsghdr *nlh,
        if (strict_check) {
                struct ifinfomsg *ifm;
 
-               if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifm))) {
+               ifm = nlmsg_payload(nlh, sizeof(*ifm));
+               if (!ifm) {
                        NL_SET_ERR_MSG(extack, "Invalid header for bridge link dump");
                        return -EINVAL;
                }
 
-               ifm = nlmsg_data(nlh);
                if (ifm->__ifi_pad || ifm->ifi_type || ifm->ifi_flags ||
                    ifm->ifi_change || ifm->ifi_index) {
                        NL_SET_ERR_MSG(extack, "Invalid values in header for bridge link dump request");
@@ -6221,7 +6221,8 @@ static int rtnl_valid_stats_req(const struct nlmsghdr *nlh, bool strict_check,
 {
        struct if_stats_msg *ifsm;
 
-       if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifsm))) {
+       ifsm = nlmsg_payload(nlh, sizeof(*ifsm));
+       if (!ifsm) {
                NL_SET_ERR_MSG(extack, "Invalid header for stats dump");
                return -EINVAL;
        }
@@ -6229,8 +6230,6 @@ static int rtnl_valid_stats_req(const struct nlmsghdr *nlh, bool strict_check,
        if (!strict_check)
                return 0;
 
-       ifsm = nlmsg_data(nlh);
-
        /* only requests using strict checks can pass data to influence
         * the dump. The legacy exception is filter_mask.
         */
@@ -6458,12 +6457,12 @@ static int rtnl_mdb_valid_dump_req(const struct nlmsghdr *nlh,
 {
        struct br_port_msg *bpm;
 
-       if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*bpm))) {
+       bpm = nlmsg_payload(nlh, sizeof(*bpm));
+       if (!bpm) {
                NL_SET_ERR_MSG(extack, "Invalid header for mdb dump request");
                return -EINVAL;
        }
 
-       bpm = nlmsg_data(nlh);
        if (bpm->ifindex) {
                NL_SET_ERR_MSG(extack, "Filtering by device index is not supported for mdb dump request");
                return -EINVAL;