diff options
author | Roman Kapl <code@rkapl.cz> | 2018-02-19 21:32:51 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-08 22:47:35 -0800 |
commit | f156028765387fbdb0bb2360fabb89aed27e9201 (patch) | |
tree | 9d8e13f97480c5cdd963f5aef51b592d0982ac7a /net | |
parent | 70ecf3334923d2bf26fecdd9ef90202fb64cb660 (diff) |
net: sched: report if filter is too large to dump
[ Upstream commit 5ae437ad5a2ed573b1ebb04e0afa70b8869f88dd ]
So far, if the filter was too large to fit in the allocated skb, the
kernel did not return any error and stopped dumping. Modify the dumper
so that it returns -EMSGSIZE when a filter fails to dump and it is the
first filter in the skb. If we are not first, we will get a next chance
with more room.
I understand this is pretty near to being an API change, but the
original design (silent truncation) can be considered a bug.
Note: The error case can happen pretty easily if you create a filter
with 32 actions and have 4kb pages. Also recent versions of iproute try
to be clever with their buffer allocation size, which in turn leads to
Signed-off-by: Roman Kapl <code@rkapl.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r-- | net/sched/cls_api.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index e6b853f0ee4f..2e437bbd3358 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -1054,13 +1054,18 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb) nla_get_u32(tca[TCA_CHAIN]) != chain->index) continue; if (!tcf_chain_dump(chain, q, parent, skb, cb, - index_start, &index)) + index_start, &index)) { + err = -EMSGSIZE; break; + } } cb->args[0] = index; out: + /* If we did no progress, the error (EMSGSIZE) is real */ + if (skb->len == 0 && err) + return err; return skb->len; } |