From: Sergei Shtylyov <sergei.shtylyov@cogentembedded•com>
To: David Gibson <david@gibson•dropbear.id.au>, netdev@vger•kernel.org
Cc: ssujith@cisco•com, neepatel@cisco•com, benve@cisco•com,
davem@davemloft•net, ben@decadent•org.uk,
govindarajulu90@gmail•com, gregory.v.rose@intel•com
Subject: Re: [PATCH 1/2] rtnetlink: Warn when interface's information won't fit in our packet
Date: Wed, 23 Apr 2014 18:20:14 +0400 [thread overview]
Message-ID: <5357CC1E.6070609@cogentembedded.com> (raw)
In-Reply-To: <1398237665-26980-2-git-send-email-david@gibson.dropbear.id.au>
Hello.
On 23-04-2014 11:21, David Gibson wrote:
> Without IFLA_EXT_MASK specified, the information reported for a single
> interface in response to RTM_GETLINK is expected to fit within a netlink
> packet of NLMSG_GOODSIZE.
> If it doesn't, however, things will go badly wrong, When listing all
> interfaces, netlink_dump() will incorrectly treat -EMSGSIZE on the first
> message in a packet as the end of the listing and omit information for
> that interface and all subsequent ones. This can cause getifaddrs(3) to
> enter an infinite loop.
> This patch won't fix the problem, but it will WARN_ON() making it easier to
> track down what's going wrong.
> Signed-off-by: David Gibson <david@gibson•dropbear.id.au>
> ---
> net/core/rtnetlink.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index d4ff417..5331db2 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
[...]
> @@ -1218,11 +1219,16 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
> hlist_for_each_entry_rcu(dev, head, index_hlist) {
> if (idx < s_idx)
> goto cont;
> - if (rtnl_fill_ifinfo(skb, dev, RTM_NEWLINK,
> - NETLINK_CB(cb->skb).portid,
> - cb->nlh->nlmsg_seq, 0,
> - NLM_F_MULTI,
> - ext_filter_mask) <= 0)
> + err = rtnl_fill_ifinfo(skb, dev, RTM_NEWLINK,
> + NETLINK_CB(cb->skb).portid,
> + cb->nlh->nlmsg_seq, 0,
> + NLM_F_MULTI,
> + ext_filter_mask);
> + /* If we ran out of room on the first message,
> + * we're in trouble */
Hm, comment style... multi-line comments in the networking code should
look like this:
/* bla
* bla
*/
> + WARN_ON((err == -EMSGSIZE) && (skb->len == 0));
> +
> + if (err <= 0)
WBR, Sergei
next prev parent reply other threads:[~2014-04-23 14:20 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-23 7:21 [0/2] Fix problems with with IFLA_VF_PORTS David Gibson
2014-04-23 7:21 ` [PATCH 1/2] rtnetlink: Warn when interface's information won't fit in our packet David Gibson
2014-04-23 9:09 ` Jiri Pirko
2014-04-23 11:41 ` David Gibson
2014-04-23 11:51 ` Jiri Pirko
2014-04-23 14:20 ` Sergei Shtylyov [this message]
2014-04-23 7:21 ` [PATCH 2/2] rtnetlink: Only supply IFLA_VF_PORTS information when RTEXT_FILTER_VF is set David Gibson
2014-04-23 9:17 ` Jiri Pirko
2014-04-24 0:13 ` David Gibson
2014-04-23 15:14 ` [0/2] Fix problems with with IFLA_VF_PORTS Greg Rose
-- strict thread matches above, loose matches on Subject: below --
2014-04-24 0:22 [0/2] Fix problems with with IFLA_VF_PORTS (v2) David Gibson
2014-04-24 0:22 ` [PATCH 1/2] rtnetlink: Warn when interface's information won't fit in our packet David Gibson
2014-04-24 15:49 ` Jiri Pirko
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