From a00302b60777077a428473b8e132756e5d4f48d4 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Fri, 18 Jan 2019 10:46:19 -0800 Subject: net: ipv4: route: perform strict checks also for doit handlers Make RTM_GETROUTE's doit handler use strict checks when NETLINK_F_STRICT_CHK is set. v2: - new patch (DaveA). Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller --- net/ipv4/route.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 70 insertions(+), 2 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/route.c b/net/ipv4/route.c index ce92f73cf104..99be68b15da0 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2763,6 +2763,75 @@ static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst, return skb; } +static int inet_rtm_valid_getroute_req(struct sk_buff *skb, + const struct nlmsghdr *nlh, + struct nlattr **tb, + struct netlink_ext_ack *extack) +{ + struct rtmsg *rtm; + int i, err; + + if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) { + NL_SET_ERR_MSG(extack, + "ipv4: Invalid header for route get request"); + return -EINVAL; + } + + if (!netlink_strict_get_check(skb)) + return nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, + rtm_ipv4_policy, extack); + + rtm = nlmsg_data(nlh); + if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) || + (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) || + rtm->rtm_table || rtm->rtm_protocol || + rtm->rtm_scope || rtm->rtm_type) { + NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request"); + return -EINVAL; + } + + if (rtm->rtm_flags & ~(RTM_F_NOTIFY | + RTM_F_LOOKUP_TABLE | + RTM_F_FIB_MATCH)) { + NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request"); + return -EINVAL; + } + + err = nlmsg_parse_strict(nlh, sizeof(*rtm), tb, RTA_MAX, + rtm_ipv4_policy, extack); + if (err) + return err; + + if ((tb[RTA_SRC] && !rtm->rtm_src_len) || + (tb[RTA_DST] && !rtm->rtm_dst_len)) { + NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4"); + return -EINVAL; + } + + for (i = 0; i <= RTA_MAX; i++) { + if (!tb[i]) + continue; + + switch (i) { + case RTA_IIF: + case RTA_OIF: + case RTA_SRC: + case RTA_DST: + case RTA_IP_PROTO: + case RTA_SPORT: + case RTA_DPORT: + case RTA_MARK: + case RTA_UID: + break; + default: + NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request"); + return -EINVAL; + } + } + + return 0; +} + static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, struct netlink_ext_ack *extack) { @@ -2783,8 +2852,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err; int mark; - err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy, - extack); + err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack); if (err < 0) return err; -- cgit v1.2.3-59-g8ed1b