Re: [PATCH v2 net-next 16/23] net/neighbor: Update neightbl_dump_info for strict data checking
From: Christian Brauner <christian@brauner.io>
Date: 2018-10-08 17:59:13
On Sun, Oct 07, 2018 at 08:16:37PM -0700, David Ahern wrote:
From: David Ahern <redacted> Update neightbl_dump_info for strict data checking. If the flag is set, the dump request is expected to have an ndtmsg struct as the header. All elements of the struct are expected to be 0 and no attributes can be appended. Signed-off-by: David Ahern <redacted>
Acked-by: Christian Brauner <christian@brauner.io>
quoted hunk ↗ jump to hunk
--- net/core/neighbour.c | 38 +++++++++++++++++++++++++++++++++++--- 1 file changed, 35 insertions(+), 3 deletions(-)diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 7c8a3a0ee059..dc1389b8beb1 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c@@ -2164,15 +2164,47 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh, return err; } +static int neightbl_valid_dump_info(const struct nlmsghdr *nlh, + struct netlink_ext_ack *extack) +{ + struct ndtmsg *ndtm; + + if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ndtm))) { + NL_SET_ERR_MSG(extack, "Invalid header for neighbor table dump request"); + return -EINVAL; + } + + ndtm = nlmsg_data(nlh); + if (ndtm->ndtm_pad1 || ndtm->ndtm_pad2) { + NL_SET_ERR_MSG(extack, "Invalid values in header for neighbor table dump request"); + return -EINVAL; + } + + if (nlmsg_attrlen(nlh, sizeof(*ndtm))) { + NL_SET_ERR_MSG(extack, "Invalid data after header in neighbor table dump request"); + return -EINVAL; + } + + return 0; +} + static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb) { + const struct nlmsghdr *nlh = cb->nlh; struct net *net = sock_net(skb->sk); int family, tidx, nidx = 0; int tbl_skip = cb->args[0]; int neigh_skip = cb->args[1]; struct neigh_table *tbl; - family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family; + if (cb->strict_check) { + int err = neightbl_valid_dump_info(nlh, cb->extack); + + if (err < 0) + return err; + } + + family = ((struct rtgenmsg *)nlmsg_data(nlh))->rtgen_family; for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) { struct neigh_parms *p;@@ -2185,7 +2217,7 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb) continue; if (neightbl_fill_info(skb, tbl, NETLINK_CB(cb->skb).portid, - cb->nlh->nlmsg_seq, RTM_NEWNEIGHTBL, + nlh->nlmsg_seq, RTM_NEWNEIGHTBL, NLM_F_MULTI) < 0) break;@@ -2200,7 +2232,7 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb) if (neightbl_fill_param_info(skb, tbl, p, NETLINK_CB(cb->skb).portid, - cb->nlh->nlmsg_seq, + nlh->nlmsg_seq, RTM_NEWNEIGHTBL, NLM_F_MULTI) < 0) goto out;-- 2.11.0