@@ -1053,6 +1053,7 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
struct nlattr *tb[IFLA_MAX+1];
u32 ext_filter_mask = 0;
int err;
+ int hdrlen;
s_h = cb->args[0];
s_idx = cb->args[1];
@@ -1060,8 +1061,17 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
rcu_read_lock();
cb->seq = net->dev_base_seq;
- if (nlmsg_parse(cb->nlh, sizeof(struct ifinfomsg), tb, IFLA_MAX,
- ifla_policy) >= 0) {
+ /* A hack to preserve kernel<->userspace interface.
+ * The correct header is ifinfomsg. It is consistent with rtnl_getlink.
+ * However, before Linux v3.9 the code here assumed rtgenmsg and that's
+ * what iproute2 < v3.9.0 used.
+ * We can detect the old iproute2. Even including the IFLA_EXT_MASK
+ * attribute, its netlink message is shorter than struct ifinfomsg.
+ */
+ hdrlen = nlmsg_len(cb->nlh) < sizeof(struct ifinfomsg) ?
+ sizeof(struct rtgenmsg) : sizeof(struct ifinfomsg);
+
+ if (nlmsg_parse(cb->nlh, hdrlen, tb, IFLA_MAX, ifla_policy) >= 0) {
if (tb[IFLA_EXT_MASK])
ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]);
@@ -1925,9 +1935,13 @@ static u16 rtnl_calcit(struct sk_buff *skb, struct nlmsghdr *nlh)
struct nlattr *tb[IFLA_MAX+1];
u32 ext_filter_mask = 0;
u16 min_ifinfo_dump_size = 0;
+ int hdrlen;
+
+ /* Same kernel<->userspace interface hack as in rtnl_dump_ifinfo. */
+ hdrlen = nlmsg_len(nlh) < sizeof(struct ifinfomsg) ?
+ sizeof(struct rtgenmsg) : sizeof(struct ifinfomsg);
- if (nlmsg_parse(nlh, sizeof(struct ifinfomsg), tb, IFLA_MAX,
- ifla_policy) >= 0) {
+ if (nlmsg_parse(nlh, hdrlen, tb, IFLA_MAX, ifla_policy) >= 0) {
if (tb[IFLA_EXT_MASK])
ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]);
}
This is a note to let you know that I have just added a patch titled rtnetlink: fix userspace API breakage for iproute2 < v3.9.0 to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.11.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 789606f064e17586b4a4ba03efe3ff236e491354 Mon Sep 17 00:00:00 2001 From: Michal Schmidt <mschmidt@redhat.com> Date: Wed, 28 May 2014 14:15:19 +0200 Subject: rtnetlink: fix userspace API breakage for iproute2 < v3.9.0 commit e5eca6d41f53db48edd8cf88a3f59d2c30227f8e upstream. When running RHEL6 userspace on a current upstream kernel, "ip link" fails to show VF information. The reason is a kernel<->userspace API change introduced by commit 88c5b5ce5cb57 ("rtnetlink: Call nlmsg_parse() with correct header length"), after which the kernel does not see iproute2's IFLA_EXT_MASK attribute in the netlink request. iproute2 adjusted for the API change in its commit 63338dca4513 ("libnetlink: Use ifinfomsg instead of rtgenmsg in rtnl_wilddump_req_filter"). The problem has been noticed before: http://marc.info/?l=linux-netdev&m=136692296022182&w=2 (Subject: Re: getting VF link info seems to be broken in 3.9-rc8) We can do better than tell those with old userspace to upgrade. We can recognize the old iproute2 in the kernel by checking the netlink message length. Even when including the IFLA_EXT_MASK attribute, its netlink message is shorter than struct ifinfomsg. With this patch "ip link" shows VF information in both old and new iproute2 versions. Signed-off-by: Michal Schmidt <mschmidt@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> [ luis: backported to 3.11: adjusted context ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- net/core/rtnetlink.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) -- 1.9.1