From ebfe3c5183733f784264450a41646a482f964e5e Mon Sep 17 00:00:00 2001 From: Di Zhu Date: Wed, 21 Oct 2020 10:00:53 +0800 Subject: rtnetlink: fix data overflow in rtnl_calcit() "ip addr show" command execute error when we have a physical network card with a large number of VFs The return value of if_nlmsg_size() in rtnl_calcit() will exceed range of u16 data type when any network cards has a larger number of VFs. rtnl_vfinfo_size() will significant increase needed dump size when the value of num_vfs is larger. Eventually we get a wrong value of min_ifinfo_dump_size because of overflow which decides the memory size needed by netlink dump and netlink_dump() will return -EMSGSIZE because of not enough memory was allocated. So fix it by promoting min_dump_alloc data type to u32 to avoid whole netlink message size overflow and it's also align with the data type of struct netlink_callback{}.min_dump_alloc which is assigned by return value of rtnl_calcit() Signed-off-by: Di Zhu Link: https://lore.kernel.org/r/20201021020053.1401-1-zhudi21@huawei.com Signed-off-by: Jakub Kicinski --- net/core/rtnetlink.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'net') diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 68e0682450c6..7d7223691783 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3709,13 +3709,13 @@ static int rtnl_dellinkprop(struct sk_buff *skb, struct nlmsghdr *nlh, return rtnl_linkprop(RTM_DELLINKPROP, skb, nlh, extack); } -static u16 rtnl_calcit(struct sk_buff *skb, struct nlmsghdr *nlh) +static u32 rtnl_calcit(struct sk_buff *skb, struct nlmsghdr *nlh) { struct net *net = sock_net(skb->sk); - struct net_device *dev; + size_t min_ifinfo_dump_size = 0; struct nlattr *tb[IFLA_MAX+1]; u32 ext_filter_mask = 0; - u16 min_ifinfo_dump_size = 0; + struct net_device *dev; int hdrlen; /* Same kernel<->userspace interface hack as in rtnl_dump_ifinfo. */ @@ -3735,9 +3735,8 @@ static u16 rtnl_calcit(struct sk_buff *skb, struct nlmsghdr *nlh) */ rcu_read_lock(); for_each_netdev_rcu(net, dev) { - min_ifinfo_dump_size = max_t(u16, min_ifinfo_dump_size, - if_nlmsg_size(dev, - ext_filter_mask)); + min_ifinfo_dump_size = max(min_ifinfo_dump_size, + if_nlmsg_size(dev, ext_filter_mask)); } rcu_read_unlock(); @@ -5494,7 +5493,7 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) { struct sock *rtnl; rtnl_dumpit_func dumpit; - u16 min_dump_alloc = 0; + u32 min_dump_alloc = 0; link = rtnl_get_link(family, type); if (!link || !link->dumpit) { -- cgit v1.2.3-59-g8ed1b