From: Luca Boccassi <bluca@debian.org>
Date: Thu, 14 Feb 2019 23:29:18 +0000 (+0000)
Subject: ip route: get: allow zero-length subnet mask
X-Git-Tag: v5.0.0~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c2f9dc14c41f388764f7634d36c3d05e354f053a;p=thirdparty%2Fiproute2.git

ip route: get: allow zero-length subnet mask

A /0 subnet mask is theoretically valid, but ip route get doesn't allow
it:

$ ip route get 1.0.0.0/0
need at least a destination address

Change the check and remember whether we found an address or not, since
according to the documentation it's a mandatory parameter.

$ ip/ip route get 1.0.0.0/0
1.0.0.0 via 192.168.1.1 dev eth0 src 192.168.1.91 uid 1000
    cache

Reported-by: Clément Hertling <wxcafe@wxcafe.net>
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 5f58a3b34..cc02a3e1b 100644
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -1932,6 +1932,7 @@ static int iproute_get(int argc, char **argv)
 	int fib_match = 0;
 	int from_ok = 0;
 	unsigned int mark = 0;
+	bool address_found = false;
 
 	iproute_reset_filter(0);
 	filter.cloned = 2;
@@ -2037,11 +2038,12 @@ static int iproute_get(int argc, char **argv)
 				addattr_l(&req.n, sizeof(req),
 					  RTA_DST, &addr.data, addr.bytelen);
 			req.r.rtm_dst_len = addr.bitlen;
+			address_found = true;
 		}
 		argc--; argv++;
 	}
 
-	if (req.r.rtm_dst_len == 0) {
+	if (!address_found) {
 		fprintf(stderr, "need at least a destination address\n");
 		return -1;
 	}