From b9e8ae1d8a424194b4e185359da4ded163f24f4e Mon Sep 17 00:00:00 2001 From: Mike Karels Date: Mon, 15 Jan 2024 15:14:54 -0600 Subject: [PATCH] route: error on IPv4 network routes with incorrect destination Route destinations like 10/8 are most likely intended as a shorthand for 10.0.0.0/8, but instead it means 0.0.0.10/8, which includes only bits in the host part of the mask, and hence adds a route to 0.0.0.0/8. In 12.x, there was code to "do what I mean", which was removed as part of a cleanup of old network class remnants. Given that we have gone this long without that code, do not restore that behavior. Instead, detect the issue and produce an error. Specifically, if there are no dots in a numeric IPv4 address, the mask is specified with CIDR notation (using a slash), and there are bits set in the host part, produce an error like this for 10/8: route: malformed address, bits set after mask; 10 means 0.0.0.10 PR: 258874 MFC after: 1 week Reviewed by: melifaro, emaste Differential Revision: https://reviews.freebsd.org/D43384 --- sbin/route/route.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/sbin/route/route.c b/sbin/route/route.c index c39a13b252bb..03844308fe84 100644 --- a/sbin/route/route.c +++ b/sbin/route/route.c @@ -1329,6 +1329,9 @@ getaddr(int idx, char *str, int nrflags) q = strchr(str,'/'); if (q != NULL && idx == RTAX_DST) { /* A.B.C.D/NUM */ + struct sockaddr_in *mask; + uint32_t mask_bits; + *q = '\0'; if (inet_aton(str, &sin->sin_addr) == 0) errx(EX_NOHOST, "bad address: %s", str); @@ -1338,6 +1341,20 @@ getaddr(int idx, char *str, int nrflags) errx(EX_NOHOST, "bad mask length: %s", q + 1); inet_makemask((struct sockaddr_in *)&so[RTAX_NETMASK],masklen); + + /* + * Check for bogus destination such as "10/8"; heuristic is + * that there are bits set in the host part, and no dot + * is present. + */ + mask = ((struct sockaddr_in *) &so[RTAX_NETMASK]); + mask_bits = ntohl(mask->sin_addr.s_addr); + if ((ntohl(sin->sin_addr.s_addr) & ~mask_bits) != 0 && + strchr(str, '.') == NULL) + errx(EX_NOHOST, + "malformed address, bits set after mask;" + " %s means %s", + str, inet_ntoa(sin->sin_addr)); return (0); } if (inet_aton(str, &sin->sin_addr) != 0)