Patch "net/sched: cls_u32: fix cls_u32 on filter replace" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

net/sched: cls_u32: fix cls_u32 on filter replace

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     net-sched-cls_u32-fix-cls_u32-on-filter-replace.patch

and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ivan Vecera <[email protected]>
Date: Thu, 8 Feb 2018 16:10:39 +0100
Subject: net/sched: cls_u32: fix cls_u32 on filter replace

From: Ivan Vecera <[email protected]>

[ Upstream commit eb53f7af6f15285e2f6ada97285395343ce9f433 ]

The following sequence is currently broken:

 # tc qdisc add dev foo ingress
 # tc filter replace dev foo protocol all ingress \
   u32 match u8 0 0 action mirred egress mirror dev bar1
 # tc filter replace dev foo protocol all ingress \
   handle 800::800 pref 49152 \
   u32 match u8 0 0 action mirred egress mirror dev bar2
 Error: cls_u32: Key node flags do not match passed flags.
 We have an error talking to the kernel, -1

The error comes from u32_change() when comparing new and existing flags. The existing ones always contains one of TCA_CLS_FLAGS_{,NOT}_IN_HW flag depending on offloading state. These flags cannot be passed from userspace so the condition (n->flags != flags) in u32_change() always fails.

Fix the condition so the flags TCA_CLS_FLAGS_NOT_IN_HW and TCA_CLS_FLAGS_IN_HW are not taken into account.

---
 net/sched/cls_u32.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -928,7 +928,8 @@ static int u32_change(struct net *net, s
 		if (TC_U32_KEY(n->handle) == 0)
 			return -EINVAL;
 
-		if (n->flags != flags)
+		if ((n->flags ^ flags) &
+		    ~(TCA_CLS_FLAGS_IN_HW | TCA_CLS_FLAGS_NOT_IN_HW))
 			return -EINVAL;
 
 		new = u32_init_knode(tp, n);

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/net-sched-cls_u32-fix-cls_u32-on-filter-replace.patch