On 10/15/2015 08:01 AM, Matan Barak wrote:
> When using ifup/ifdown while executing enum_netdev_ipv4_ips,
> ifa could become invalid and cause use after free error.
> Fixing it by protecting with RCU lock.
>
> Fixes: 03db3a2d81e6 ('IB/core: Add RoCE GID table management')
> Signed-off-by: Matan Barak <matanb@xxxxxxxxxxxx>
This is in my tree for -rc. Thanks.
> ---
>
> Hi Doug,
>
> This patch fixes a bug in RoCE GID table implementation. Under stress conditions
> where ifup/ifdown are used, the ifa pointer could become invalid. Using a
> RCU lock in order to avoid freeing the ifa node (as done in other inet functions
> (for example, inet_addr_onlink).
>
> Our QA team verified that this patch fixes this issue.
>
> Thanks,
> Matan
>
> drivers/infiniband/core/roce_gid_mgmt.c | 35 +++++++++++++++++++++++++--------
> 1 file changed, 27 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/infiniband/core/roce_gid_mgmt.c b/drivers/infiniband/core/roce_gid_mgmt.c
> index 6b24cba..178f984 100644
> --- a/drivers/infiniband/core/roce_gid_mgmt.c
> +++ b/drivers/infiniband/core/roce_gid_mgmt.c
> @@ -250,25 +250,44 @@ static void enum_netdev_ipv4_ips(struct ib_device *ib_dev,
> u8 port, struct net_device *ndev)
> {
> struct in_device *in_dev;
> + struct sin_list {
> + struct list_head list;
> + struct sockaddr_in ip;
> + };
> + struct sin_list *sin_iter;
> + struct sin_list *sin_temp;
>
> + LIST_HEAD(sin_list);
> if (ndev->reg_state >= NETREG_UNREGISTERING)
> return;
>
> - in_dev = in_dev_get(ndev);
> - if (!in_dev)
> + rcu_read_lock();
> + in_dev = __in_dev_get_rcu(ndev);
> + if (!in_dev) {
> + rcu_read_unlock();
> return;
> + }
>
> for_ifa(in_dev) {
> - struct sockaddr_in ip;
> + struct sin_list *entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
>
> - ip.sin_family = AF_INET;
> - ip.sin_addr.s_addr = ifa->ifa_address;
> - update_gid_ip(GID_ADD, ib_dev, port, ndev,
> - (struct sockaddr *)&ip);
> + if (!entry) {
> + pr_warn("roce_gid_mgmt: couldn't allocate entry for IPv4 update\n");
> + continue;
> + }
> + entry->ip.sin_family = AF_INET;
> + entry->ip.sin_addr.s_addr = ifa->ifa_address;
> + list_add_tail(&entry->list, &sin_list);
> }
> endfor_ifa(in_dev);
> + rcu_read_unlock();
>
> - in_dev_put(in_dev);
> + list_for_each_entry_safe(sin_iter, sin_temp, &sin_list, list) {
> + update_gid_ip(GID_ADD, ib_dev, port, ndev,
> + (struct sockaddr *)&sin_iter->ip);
> + list_del(&sin_iter->list);
> + kfree(sin_iter);
> + }
> }
>
> static void enum_netdev_ipv6_ips(struct ib_device *ib_dev,
>
--
Doug Ledford <dledford@xxxxxxxxxx>
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