iplink: forbid negative ifindex and modifying ifindex

Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

diff --git a/ip/iplink.c b/ip/iplink.c
index ea06871b7c815024bf6c6e5957da66e03a1472ba..a8a19dd6725a09d912d7c93c8a51d66760863604 100644 (file)
--- a/ip/iplink.c
+++ b/ip/iplink.c
@@ -400,6 +400,8 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req,
                } else if (strcmp(*argv, "index") == 0) {
                        NEXT_ARG();
                        *index = atoi(*argv);
+                       if (*index < 0)
+                               invarg("Invalid \"index\" value", *argv);
                } else if (matches(*argv, "link") == 0) {
                        NEXT_ARG();
                        *link = *argv;
@@ -607,7 +609,7 @@ static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv)
        char *name = NULL;
        char *link = NULL;
        char *type = NULL;
-       int index = 0;
+       int index = -1;
        int group;
        struct link_util *lu = NULL;
        struct iplink_req req;
@@ -658,6 +660,11 @@ static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv)
                                        "argument is required.\n");
                        exit(-1);
                }
+               if (cmd == RTM_NEWLINK && index != -1) {
+                       fprintf(stderr, "index can be used only when "
+                                       "creating devices.\n");
+                       exit(-1);
+               }
 
                req.i.ifi_index = ll_name_to_index(dev);
                if (req.i.ifi_index == 0) {