From ddb3712552c8807c75576fb4fbdbb16f0d48b161 Mon Sep 17 00:00:00 2001 From: Richard Alpe Date: Thu, 3 Mar 2016 14:20:42 +0100 Subject: [PATCH] tipc: safely copy UDP netlink data from user The netlink policy for TIPC_NLA_UDP_LOCAL and TIPC_NLA_UDP_REMOTE is of type binary with a defined length. This causes the policy framework to threat the defined length as maximum length. There is however no protection against a user sending a smaller amount of data. Prior to this patch this wasn't handled which could result in a partially incomplete sockaddr_storage struct containing uninitialized data. In this patch we use nla_memcpy() when copying the user data. This ensures a potential gap at the end is cleared out properly. This was found by Julia with Coccinelle tool. Reported-by: Daniel Borkmann Reported-by: Julia Lawall Signed-off-by: Richard Alpe Acked-by: Jon Maloy Reviewed-by: Erik Hugne Signed-off-by: David S. Miller --- net/tipc/udp_media.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c index f22a5bb169c9..6fe8740a226f 100644 --- a/net/tipc/udp_media.c +++ b/net/tipc/udp_media.c @@ -276,7 +276,7 @@ static int parse_options(struct nlattr *attrs[], struct udp_bearer *ub, struct udp_media_addr *remote) { struct nlattr *opts[TIPC_NLA_UDP_MAX + 1]; - struct sockaddr_storage *sa_local, *sa_remote; + struct sockaddr_storage sa_local, sa_remote; if (!attrs[TIPC_NLA_BEARER_UDP_OPTS]) goto err; @@ -285,41 +285,43 @@ static int parse_options(struct nlattr *attrs[], struct udp_bearer *ub, tipc_nl_udp_policy)) goto err; if (opts[TIPC_NLA_UDP_LOCAL] && opts[TIPC_NLA_UDP_REMOTE]) { - sa_local = nla_data(opts[TIPC_NLA_UDP_LOCAL]); - sa_remote = nla_data(opts[TIPC_NLA_UDP_REMOTE]); + nla_memcpy(&sa_local, opts[TIPC_NLA_UDP_LOCAL], + sizeof(sa_local)); + nla_memcpy(&sa_remote, opts[TIPC_NLA_UDP_REMOTE], + sizeof(sa_remote)); } else { err: pr_err("Invalid UDP bearer configuration"); return -EINVAL; } - if ((sa_local->ss_family & sa_remote->ss_family) == AF_INET) { + if ((sa_local.ss_family & sa_remote.ss_family) == AF_INET) { struct sockaddr_in *ip4; - ip4 = (struct sockaddr_in *)sa_local; + ip4 = (struct sockaddr_in *)&sa_local; local->proto = htons(ETH_P_IP); local->udp_port = ip4->sin_port; local->ipv4.s_addr = ip4->sin_addr.s_addr; - ip4 = (struct sockaddr_in *)sa_remote; + ip4 = (struct sockaddr_in *)&sa_remote; remote->proto = htons(ETH_P_IP); remote->udp_port = ip4->sin_port; remote->ipv4.s_addr = ip4->sin_addr.s_addr; return 0; #if IS_ENABLED(CONFIG_IPV6) - } else if ((sa_local->ss_family & sa_remote->ss_family) == AF_INET6) { + } else if ((sa_local.ss_family & sa_remote.ss_family) == AF_INET6) { struct sockaddr_in6 *ip6; - ip6 = (struct sockaddr_in6 *)sa_local; + ip6 = (struct sockaddr_in6 *)&sa_local; local->proto = htons(ETH_P_IPV6); local->udp_port = ip6->sin6_port; - local->ipv6 = ip6->sin6_addr; + memcpy(&local->ipv6, &ip6->sin6_addr, sizeof(struct in6_addr)); ub->ifindex = ip6->sin6_scope_id; - ip6 = (struct sockaddr_in6 *)sa_remote; + ip6 = (struct sockaddr_in6 *)&sa_remote; remote->proto = htons(ETH_P_IPV6); remote->udp_port = ip6->sin6_port; - remote->ipv6 = ip6->sin6_addr; + memcpy(&remote->ipv6, &ip6->sin6_addr, sizeof(struct in6_addr)); return 0; #endif } -- 2.11.0