net: cls_bpf: fix auto generation of per list handles
When creating a bpf classifier in tc with priority collisions and
invoking automatic unique handle assignment, cls_bpf_grab_new_handle()
will return a wrong handle id which in fact is non-unique. Usually
altering of specific filters is being addressed over major id, but
in case of collisions we result in a filter chain, where handle ids
address individual cls_bpf_progs inside the classifier.
Issue is, in cls_bpf_grab_new_handle() we probe for head->hgen handle
in cls_bpf_get() and in case we found a free handle, we're supposed
to use exactly head->hgen. In case of insufficient numbers of handles,
we bail out later as handle id 0 is not allowed.
Fixes: 7d1d65cb84e1 ("net: sched: cls_bpf: add BPF-based classifier")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
index 49e5fa8..f59adf8 100644
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -220,15 +220,21 @@
struct cls_bpf_head *head)
{
unsigned int i = 0x80000000;
+ u32 handle;
do {
if (++head->hgen == 0x7FFFFFFF)
head->hgen = 1;
} while (--i > 0 && cls_bpf_get(tp, head->hgen));
- if (i == 0)
- pr_err("Insufficient number of handles\n");
- return i;
+ if (unlikely(i == 0)) {
+ pr_err("Insufficient number of handles\n");
+ handle = 0;
+ } else {
+ handle = head->hgen;
+ }
+
+ return handle;
}
static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,