From d0440029831bcb21ceb89a3dbcadc7d6dca0a39a Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Fri, 18 Jan 2019 10:46:20 -0800 Subject: [PATCH] net: ipv4: ipmr: perform strict checks also for doit handlers Make RTM_GETROUTE's doit handler use strict checks when NETLINK_F_STRICT_CHK is set. v2: - improve extack messages (DaveA). Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller --- net/ipv4/ipmr.c | 61 +++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 56 insertions(+), 5 deletions(-) diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index ddbf8c9a1abb..fb99002c3d4e 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -2467,6 +2467,61 @@ errout: rtnl_set_sk_err(net, RTNLGRP_IPV4_MROUTE_R, -ENOBUFS); } +static int ipmr_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 multicast 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_tos || rtm->rtm_table || rtm->rtm_protocol || + rtm->rtm_scope || rtm->rtm_type || rtm->rtm_flags) { + NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for multicast 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_SRC: + case RTA_DST: + case RTA_TABLE: + break; + default: + NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in multicast route get request"); + return -EINVAL; + } + } + + return 0; +} + static int ipmr_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, struct netlink_ext_ack *extack) { @@ -2475,18 +2530,14 @@ static int ipmr_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, struct sk_buff *skb = NULL; struct mfc_cache *cache; struct mr_table *mrt; - struct rtmsg *rtm; __be32 src, grp; u32 tableid; int err; - err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, - rtm_ipv4_policy, extack); + err = ipmr_rtm_valid_getroute_req(in_skb, nlh, tb, extack); if (err < 0) goto errout; - rtm = nlmsg_data(nlh); - src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; grp = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; tableid = tb[RTA_TABLE] ? nla_get_u32(tb[RTA_TABLE]) : 0; -- 2.30.2