3.13.11-ckt17 -stable review patch. If anyone has any objections, please let
me know.
------------------
From: Daniel Borkmann <dbork...@redhat.com>
commit 3f2ab135946dcd4eb6af92a53d6d4bd35e7526ca upstream.
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 <dbork...@redhat.com>
Acked-by: Jiri Pirko <j...@resnulli.us>
Acked-by: Alexei Starovoitov <a...@plumgrid.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Kamal Mostafa <ka...@canonical.com>
---
net/sched/cls_bpf.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
index 520b1a4..7181cf5 100644
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -237,15 +237,21 @@ static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp,
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)
+
+ if (unlikely(i == 0)) {
pr_err("Insufficient number of handles\n");
+ handle = 0;
+ } else {
+ handle = head->hgen;
+ }
- return i;
+ return handle;
}
static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
--
1.9.1
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