zebra: fix logging of MPLS labels

* use %u instead of %d, we don't want to print negative labels;
* increase the size of label_buf to accommodate the worst case scenarios;
* use strlcat() instead of strcat() as a security best practice.

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

diff --git a/zebra/rt_netlink.c b/zebra/rt_netlink.c
index a939dde8d521e446895ceaeff4820389a77a5625..3b2d22fa952f676f9ac8a69ad6495391507bfa74 100644 (file)
--- a/zebra/rt_netlink.c
+++ b/zebra/rt_netlink.c
@@ -845,7 +845,7 @@ static void _netlink_route_build_singlepath(const char *routedesc, int bytelen,
 {
        struct nexthop_label *nh_label;
        mpls_lse_t out_lse[MPLS_MAX_LABELS];
-       char label_buf[100];
+       char label_buf[256];
 
        /*
         * label_buf is *only* currently used within debugging.
@@ -876,12 +876,13 @@ static void _netlink_route_build_singlepath(const char *routedesc, int bytelen,
                                                             0, 0, bos);
                                if (IS_ZEBRA_DEBUG_KERNEL) {
                                        if (!num_labels)
-                                               sprintf(label_buf, "label %d",
+                                               sprintf(label_buf, "label %u",
                                                        nh_label->label[i]);
                                        else {
-                                               sprintf(label_buf1, "/%d",
+                                               sprintf(label_buf1, "/%u",
                                                        nh_label->label[i]);
-                                               strcat(label_buf, label_buf1);
+                                               strlcat(label_buf, label_buf1,
+                                                       sizeof(label_buf));
                                        }
                                }
                                num_labels++;
@@ -1044,7 +1045,7 @@ static void _netlink_route_build_multipath(const char *routedesc, int bytelen,
 {
        struct nexthop_label *nh_label;
        mpls_lse_t out_lse[MPLS_MAX_LABELS];
-       char label_buf[100];
+       char label_buf[256];
 
        rtnh->rtnh_len = sizeof(*rtnh);
        rtnh->rtnh_flags = 0;
@@ -1080,12 +1081,13 @@ static void _netlink_route_build_multipath(const char *routedesc, int bytelen,
                                                             0, 0, bos);
                                if (IS_ZEBRA_DEBUG_KERNEL) {
                                        if (!num_labels)
-                                               sprintf(label_buf, "label %d",
+                                               sprintf(label_buf, "label %u",
                                                        nh_label->label[i]);
                                        else {
-                                               sprintf(label_buf1, "/%d",
+                                               sprintf(label_buf1, "/%u",
                                                        nh_label->label[i]);
-                                               strcat(label_buf, label_buf1);
+                                               strlcat(label_buf, label_buf1,
+                                                       sizeof(label_buf));
                                        }
                                }
                                num_labels++;