From: Jakub Sitnicki <jkbs@redhat.com>
Date: Wed, 11 Apr 2018 09:43:11 +0000 (+0200)
Subject: iproute: Abort if nexthop cannot be parsed
X-Git-Tag: v4.17.0~30
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ee53b42fd8b0b0cdb857d0f5bf7467e22a3457d9;p=thirdparty%2Fiproute2.git

iproute: Abort if nexthop cannot be parsed

Attempt to add a multipath route where a nexthop definition refers to a
non-existent device causes 'ip' to crash and burn due to stack buffer
overflow:

  # ip -6 route add fd00::1/64 nexthop dev fake1
  Cannot find device "fake1"
  Cannot find device "fake1"
  Cannot find device "fake1"
  ...
  Segmentation fault (core dumped)

Don't ignore errors from the helper routine that parses the nexthop
definition, and abort immediately if parsing fails.

Signed-off-by: Jakub Sitnicki <jkbs@redhat.com>
---

diff --git a/ip/iproute.c b/ip/iproute.c
index 1d8fd8154..44351bc51 100644
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -1038,7 +1038,10 @@ static int parse_nexthops(struct nlmsghdr *n, struct rtmsg *r,
 		memset(rtnh, 0, sizeof(*rtnh));
 		rtnh->rtnh_len = sizeof(*rtnh);
 		rta->rta_len += rtnh->rtnh_len;
-		parse_one_nh(n, r, rta, rtnh, &argc, &argv);
+		if (parse_one_nh(n, r, rta, rtnh, &argc, &argv)) {
+			fprintf(stderr, "Error: cannot parse nexthop\n");
+			exit(-1);
+		}
 		rtnh = RTNH_NEXT(rtnh);
 	}