[PATCH 4.18 015/135] net: sched: Add policy validation for tc attributes

Greg Kroah-Hartman
2018-10-16T17:10:45Z

From: David Ahern <dsahern@gmail.com>

[ Upstream commit 8b4c3cdd9dd8290343ce959a132d3b334062c5b9 ]

A number of TC attributes are processed without proper validation
(e.g., length checks). Add a tca policy for all input attributes and use
when invoking nlmsg_parse.

The 2 Fixes tags below cover the latest additions. The other attributes
are a string (KIND), nested attribute (OPTIONS which does seem to have
validation in most cases), for dumps only or a flag.

Fixes: 5bc1701881e39 ("net: sched: introduce multichain support for filters")
Fixes: d47a6b0e7c492 ("net: sched: introduce ingress/egress block index attributes for qdisc")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/sched/sch_api.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)

--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1304,6 +1304,18 @@ check_loop_fn(struct Qdisc *q, unsigned
* Delete/get qdisc.
*/

+const struct nla_policy rtm_tca_policy[TCA_MAX + 1] = {
+ [TCA_KIND] = { .type = NLA_STRING },
+ [TCA_OPTIONS] = { .type = NLA_NESTED },
+ [TCA_RATE] = { .type = NLA_BINARY,
+ .len = sizeof(struct tc_estimator) },
+ [TCA_STAB] = { .type = NLA_NESTED },
+ [TCA_DUMP_INVISIBLE] = { .type = NLA_FLAG },
+ [TCA_CHAIN] = { .type = NLA_U32 },
+ [TCA_INGRESS_BLOCK] = { .type = NLA_U32 },
+ [TCA_EGRESS_BLOCK] = { .type = NLA_U32 },
+};
+
static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
struct netlink_ext_ack *extack)
{
@@ -1320,7 +1332,8 @@ static int tc_get_qdisc(struct sk_buff *
!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
return -EPERM;

- err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, NULL, extack);
+ err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, rtm_tca_policy,
+ extack);
if (err < 0)
return err;

@@ -1404,7 +1417,8 @@ static int tc_modify_qdisc(struct sk_buf

replay:
/* Reinit, just in case something touches this. */
- err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, NULL, extack);
+ err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, rtm_tca_policy,
+ extack);
if (err < 0)
return err;

@@ -1638,7 +1652,8 @@ static int tc_dump_qdisc(struct sk_buff
idx = 0;
ASSERT_RTNL();

- err = nlmsg_parse(nlh, sizeof(struct tcmsg), tca, TCA_MAX, NULL, NULL);
+ err = nlmsg_parse(nlh, sizeof(struct tcmsg), tca, TCA_MAX,
+ rtm_tca_policy, NULL);
if (err < 0)
return err;

@@ -1857,7 +1872,8 @@ static int tc_ctl_tclass(struct sk_buff
!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
return -EPERM;

- err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, NULL, extack);
+ err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, rtm_tca_policy,
+ extack);
if (err < 0)
return err;