From: David Gibson Date: Thu, 24 Apr 2014 00:22:36 +0000 (+1000) Subject: rtnetlink: Only supply IFLA_VF_PORTS information when RTEXT_FILTER_VF is set X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=c53864fd60227de025cb79e05493b13f69843971;p=openwrt%2Fstaging%2Fblogic.git rtnetlink: Only supply IFLA_VF_PORTS information when RTEXT_FILTER_VF is set Since 115c9b81928360d769a76c632bae62d15206a94a (rtnetlink: Fix problem with buffer allocation), RTM_NEWLINK messages only contain the IFLA_VFINFO_LIST attribute if they were solicited by a GETLINK message containing an IFLA_EXT_MASK attribute with the RTEXT_FILTER_VF flag. That was done because some user programs broke when they received more data than expected - because IFLA_VFINFO_LIST contains information for each VF it can become large if there are many VFs. However, the IFLA_VF_PORTS attribute, supplied for devices which implement ndo_get_vf_port (currently the 'enic' driver only), has the same problem. It supplies per-VF information and can therefore become large, but it is not currently conditional on the IFLA_EXT_MASK value. Worse, it interacts badly with the existing EXT_MASK handling. When IFLA_EXT_MASK is not supplied, the buffer for netlink replies is fixed at NLMSG_GOODSIZE. If the information for IFLA_VF_PORTS exceeds this, then rtnl_fill_ifinfo() returns -EMSGSIZE on the first message in a packet. netlink_dump() will misinterpret this as having finished the listing and omit data for this interface and all subsequent ones. That can cause getifaddrs(3) to enter an infinite loop. This patch addresses the problem by only supplying IFLA_VF_PORTS when IFLA_EXT_MASK is supplied with the RTEXT_FILTER_VF flag set. Signed-off-by: David Gibson Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller --- diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 8db72ac88feb..9837bebf93ce 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -774,7 +774,8 @@ static inline int rtnl_vfinfo_size(const struct net_device *dev, return 0; } -static size_t rtnl_port_size(const struct net_device *dev) +static size_t rtnl_port_size(const struct net_device *dev, + u32 ext_filter_mask) { size_t port_size = nla_total_size(4) /* PORT_VF */ + nla_total_size(PORT_PROFILE_MAX) /* PORT_PROFILE */ @@ -790,7 +791,8 @@ static size_t rtnl_port_size(const struct net_device *dev) size_t port_self_size = nla_total_size(sizeof(struct nlattr)) + port_size; - if (!dev->netdev_ops->ndo_get_vf_port || !dev->dev.parent) + if (!dev->netdev_ops->ndo_get_vf_port || !dev->dev.parent || + !(ext_filter_mask & RTEXT_FILTER_VF)) return 0; if (dev_num_vf(dev->dev.parent)) return port_self_size + vf_ports_size + @@ -826,7 +828,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev, + nla_total_size(ext_filter_mask & RTEXT_FILTER_VF ? 4 : 0) /* IFLA_NUM_VF */ + rtnl_vfinfo_size(dev, ext_filter_mask) /* IFLA_VFINFO_LIST */ - + rtnl_port_size(dev) /* IFLA_VF_PORTS + IFLA_PORT_SELF */ + + rtnl_port_size(dev, ext_filter_mask) /* IFLA_VF_PORTS + IFLA_PORT_SELF */ + rtnl_link_get_size(dev) /* IFLA_LINKINFO */ + rtnl_link_get_af_size(dev) /* IFLA_AF_SPEC */ + nla_total_size(MAX_PHYS_PORT_ID_LEN); /* IFLA_PHYS_PORT_ID */ @@ -888,11 +890,13 @@ static int rtnl_port_self_fill(struct sk_buff *skb, struct net_device *dev) return 0; } -static int rtnl_port_fill(struct sk_buff *skb, struct net_device *dev) +static int rtnl_port_fill(struct sk_buff *skb, struct net_device *dev, + u32 ext_filter_mask) { int err; - if (!dev->netdev_ops->ndo_get_vf_port || !dev->dev.parent) + if (!dev->netdev_ops->ndo_get_vf_port || !dev->dev.parent || + !(ext_filter_mask & RTEXT_FILTER_VF)) return 0; err = rtnl_port_self_fill(skb, dev); @@ -1079,7 +1083,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev, nla_nest_end(skb, vfinfo); } - if (rtnl_port_fill(skb, dev)) + if (rtnl_port_fill(skb, dev, ext_filter_mask)) goto nla_put_failure; if (dev->rtnl_link_ops || rtnl_have_link_slave_info(dev)) {