"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 <zhud...@huawei.com>
---
/* v1 */
Link: https://lore.kernel.org/netdev/20201019101555.64b9f723/
/* v2 */
- Jakub Kicinski <k...@kernel.org>
- sorted the variable declarations from longest to shortest.
- use size_t for the local variable in rtnl_calcit().
- update commit message
---
include/linux/netlink.h | 2 +-
net/core/rtnetlink.c | 10 +++++-----
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 666cd0390699..9f118771e248 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -240,7 +240,7 @@ struct netlink_dump_control {
int (*done)(struct netlink_callback *);
void *data;
struct module *module;
- u16 min_dump_alloc;
+ u32 min_dump_alloc;
};
int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 68e0682450c6..d2154a2a4ab4 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. */
@@ -3735,7 +3735,7 @@ 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,
+ min_ifinfo_dump_size = max(min_ifinfo_dump_size,
if_nlmsg_size(dev,
ext_filter_mask));
}
@@ -5494,7 +5494,7 @@ 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) {
--
2.23.0
