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>
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 8121268..841c287 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -347,16 +347,17 @@
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;
}