From 369cf77a6a3e41b1110506ddf43d45804103bfde Mon Sep 17 00:00:00 2001 From: Thomas Graf <tgraf@infradead.org> Date: Thu, 11 Nov 2010 15:47:59 +0000 Subject: [PATCH] rtnetlink: Fix message size calculation for link messages nlmsg_total_size() calculates the length of a netlink message including header and alignment. nla_total_size() calculates the space an individual attribute consumes which was meant to be used in this context. Also, ensure to account for the attribute header for the IFLA_INFO_XSTATS attribute as implementations of get_xstats_size() seem to assume that we do so. The addition of two message headers minus the missing attribute header resulted in a calculated message size that was larger than required. Therefore we never risked running out of skb tailroom. Signed-off-by: Thomas Graf <tgraf@infradead.org> Acked-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net> --- net/core/rtnetlink.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 8121268ddbddfc..841c287ef40a47 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -347,16 +347,17 @@ static size_t rtnl_link_get_size(const struct net_device *dev) if (!ops) return 0; - size = nlmsg_total_size(sizeof(struct nlattr)) + /* IFLA_LINKINFO */ - nlmsg_total_size(strlen(ops->kind) + 1); /* IFLA_INFO_KIND */ + size = nla_total_size(sizeof(struct nlattr)) + /* IFLA_LINKINFO */ + nla_total_size(strlen(ops->kind) + 1); /* IFLA_INFO_KIND */ if (ops->get_size) /* IFLA_INFO_DATA + nested data */ - size += nlmsg_total_size(sizeof(struct nlattr)) + + size += nla_total_size(sizeof(struct nlattr)) + ops->get_size(dev); if (ops->get_xstats_size) - size += ops->get_xstats_size(dev); /* IFLA_INFO_XSTATS */ + /* IFLA_INFO_XSTATS */ + size += nla_total_size(ops->get_xstats_size(dev)); return size; } -- GitLab