iproute: fix printing resolved localhost

format_host_rta_r might return a cached hostname
via its return value and not use the input buffer.

Before:

$ ip -resolve -6 route
 dev lo proto kernel metric 256 pref medium

After:

$ ip/ip -resolve -6 route
localhost dev lo proto kernel metric 256 pref medium

Bug-Debian: https://bugs.debian.org/983591

Reported-by: Axel Scheepers <axel.scheepers76@gmail.com>
Signed-off-by: Luca Boccassi <bluca@debian.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/ip/iproute.c b/ip/iproute.c
index 291f1a584009c12295bcd83aa847ea18a39ff861..5853f026259358ec76710356e4f5b6f4416fc862 100644 (file)
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -796,9 +796,10 @@ int print_route(struct nlmsghdr *n, void *arg)
                                 "%s/%u", rt_addr_n2a_rta(family, tb[RTA_DST]),
                                 r->rtm_dst_len);
                } else {
-                       format_host_rta_r(family, tb[RTA_DST],
+                       const char *hostname = format_host_rta_r(family, tb[RTA_DST],
                                          b1, sizeof(b1));
-
+                       if (hostname)
+                               strncpy(b1, hostname, sizeof(b1) - 1);
                }
        } else if (r->rtm_dst_len) {
                snprintf(b1, sizeof(b1), "0/%d ", r->rtm_dst_len);
@@ -818,8 +819,10 @@ int print_route(struct nlmsghdr *n, void *arg)
                                 rt_addr_n2a_rta(family, tb[RTA_SRC]),
                                 r->rtm_src_len);
                } else {
-                       format_host_rta_r(family, tb[RTA_SRC],
+                       const char *hostname = format_host_rta_r(family, tb[RTA_SRC],
                                          b1, sizeof(b1));
+                       if (hostname)
+                               strncpy(b1, hostname, sizeof(b1) - 1);
                }
                print_color_string(PRINT_ANY, color,
                                   "from", "from %s ", b1);