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authorAl Viro <viro@zeniv.linux.org.uk>2018-10-08 13:22:33 +0300
committerDavid S. Miller <davem@davemloft.net>2018-10-08 20:33:34 +0300
commitb44ef84542dd79aeacd09d43e073e25a1bb1f407 (patch)
tree2d4248a5d38f071d82adb8215f4208d01f1d67f1 /net/sched/cls_u32.c
parent67db8c3ebe92e74e138754162c78276fd263ee50 (diff)
downloadlinux-b44ef84542dd79aeacd09d43e073e25a1bb1f407.tar.xz
net: sched: cls_u32: mark root hnode explicitly
... and produce consistent error on attempt to delete such. Existing check in u32_delete() is inconsistent - after tc qdisc add dev eth0 ingress tc filter add dev eth0 parent ffff: protocol ip prio 100 handle 1: u32 \ divisor 1 tc filter add dev eth0 parent ffff: protocol ip prio 200 handle 2: u32 \ divisor 1 both tc filter delete dev eth0 parent ffff: protocol ip prio 100 handle 801: u32 and tc filter delete dev eth0 parent ffff: protocol ip prio 100 handle 800: u32 will fail (at least with refcounting fixes), but the former will complain about an attempt to remove a busy table, while the latter will recognize it as root and yield "Not allowed to delete root node" instead. The problem with the existing check is that several tcf_proto instances might share the same tp->data and handle-to-hnode lookup will be the same for all of them. So comparing an hnode to be deleted with tp->root won't catch the case when one tp is used to try deleting the root of another. Solution is trivial - mark the root hnodes explicitly upon allocation and check for that. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/cls_u32.c')
-rw-r--r--net/sched/cls_u32.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index f218ccf1e2d9..622f4657da94 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -84,6 +84,7 @@ struct tc_u_hnode {
int refcnt;
unsigned int divisor;
struct idr handle_idr;
+ bool is_root;
struct rcu_head rcu;
u32 flags;
/* The 'ht' field MUST be the last field in structure to allow for
@@ -377,6 +378,7 @@ static int u32_init(struct tcf_proto *tp)
root_ht->refcnt++;
root_ht->handle = tp_c ? gen_new_htid(tp_c, root_ht) : 0x80000000;
root_ht->prio = tp->prio;
+ root_ht->is_root = true;
idr_init(&root_ht->handle_idr);
if (tp_c == NULL) {
@@ -692,7 +694,7 @@ static int u32_delete(struct tcf_proto *tp, void *arg, bool *last,
goto out;
}
- if (root_ht == ht) {
+ if (ht->is_root) {
NL_SET_ERR_MSG_MOD(extack, "Not allowed to delete root node");
return -EINVAL;
}