From a658c2e49f02eedafd3e1b6e30a8a9b173d7248b Mon Sep 17 00:00:00 2001 From: Kevin Darbyshire-Bryant Date: Mon, 17 Jun 2019 11:03:26 +0100 Subject: net: sched: act_ctinfo: fix action creation Use correct return value on action creation: ACT_P_CREATED. The use of incorrect return value could result in a situation where the system thought a ctinfo module was listening but actually wasn't instantiated correctly leading to an OOPS in tcf_generic_walker(). Confession time: Until very recently, development of this module has been done on 'net-next' tree to 'clean compile' level with run-time testing on backports to 4.14 & 4.19 kernels under openwrt. During the back & forward porting during development & testing, the critical ACT_P_CREATED return code got missed despite being in the 4.14 & 4.19 backports. I have now gone through the init functions, using act_csum as reference with a fine toothed comb. Bonus, no more OOPSes. I managed to also miss this issue till now due to the new strict nla_parse_nested function failing validation before action creation. As an inexperienced developer I've learned that copy/pasting/backporting/forward porting code correctly is hard. If I ever get to a developer conference I shall don the cone of shame. Signed-off-by: Kevin Darbyshire-Bryant Signed-off-by: David S. Miller --- net/sched/act_ctinfo.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/sched/act_ctinfo.c b/net/sched/act_ctinfo.c index a7d3679d7e2e..2c17f6843107 100644 --- a/net/sched/act_ctinfo.c +++ b/net/sched/act_ctinfo.c @@ -213,6 +213,7 @@ static int tcf_ctinfo_init(struct net *net, struct nlattr *nla, tcf_idr_cleanup(tn, actparm->index); return ret; } + ret = ACT_P_CREATED; } else if (err > 0) { if (bind) /* don't override defaults */ return 0; -- cgit v1.2.3 From c197d636275031aaacb6fa969221d2be22837067 Mon Sep 17 00:00:00 2001 From: Kevin Darbyshire-Bryant Date: Mon, 17 Jun 2019 11:03:27 +0100 Subject: net: sched: act_ctinfo: fix policy validation Fix nla_policy definition by specifying an exact length type attribute to CTINFO action paraneter block structure. Without this change, netlink parsing will fail validation and the action will not be instantiated. 8cb081746c03 ("netlink: make validation more configurable for future") introduced much stricter checking to attributes being passed via netlink. Existing actions were updated to use less restrictive deprecated versions of nla_parse_nested. As a new module, act_ctinfo should be designed to use the strict checking model otherwise, well, what was the point of implementing it. Confession time: Until very recently, development of this module has been done on 'net-next' tree to 'clean compile' level with run-time testing on backports to 4.14 & 4.19 kernels under openwrt. This is how I managed to miss the run-time impacts of the new strict nla_parse_nested function. I hopefully have learned something from this (glances toward laptop running a net-next kernel) There is however a still outstanding implication on iproute2 user space in that it needs to be told to pass nested netlink messages with the nested attribute actually set. So even with this kernel fix to do things correctly you still cannot instantiate a new 'strict' nla_parse_nested based action such as act_ctinfo with iproute2's tc. Signed-off-by: Kevin Darbyshire-Bryant Signed-off-by: David S. Miller --- net/sched/act_ctinfo.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/sched/act_ctinfo.c b/net/sched/act_ctinfo.c index 2c17f6843107..10eb2bb99861 100644 --- a/net/sched/act_ctinfo.c +++ b/net/sched/act_ctinfo.c @@ -141,7 +141,8 @@ out: } static const struct nla_policy ctinfo_policy[TCA_CTINFO_MAX + 1] = { - [TCA_CTINFO_ACT] = { .len = sizeof(struct + [TCA_CTINFO_ACT] = { .type = NLA_EXACT_LEN, + .len = sizeof(struct tc_ctinfo) }, [TCA_CTINFO_ZONE] = { .type = NLA_U16 }, [TCA_CTINFO_PARMS_DSCP_MASK] = { .type = NLA_U32 }, -- cgit v1.2.3