From 2deeb4772971e56d5bdac0bd3375d5eadaa827fd Mon Sep 17 00:00:00 2001 From: Kaike Wan Date: Thu, 21 Jan 2016 08:41:31 -0500 Subject: IB/sa: Fix netlink local service GFP crash The rdma netlink local service registers a handler to handle RESOLVE response and another handler to handle SET_TIMEOUT request. The first thing these handlers do is to call netlink_capable() to check the access right of the received skb to make sure that the sender has root access. Under normal conditions, such responses and requests will be directly forwarded to the handlers without going through the netlink_dump pathway (see ibnl_rcv_msg() in drivers/infiniband/core/netlink.c). However, a user application could send a RESOLVE request (not response) to the local service, which will fall into the netlink_dump pathway, where a new skb will be created without initializing the control block. This new skb will be eventually forwarded to the local service RESOLVE response handler. Unfortunately, netlink_capable() will cause general protection fault if the skb's control block is not initialized. This patch will address the problem by checking the skb first. Signed-off-by: Kaike Wan Reported-by: Dmitry Vyukov Signed-off-by: Doug Ledford --- drivers/infiniband/core/sa_query.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'drivers/infiniband/core/sa_query.c') diff --git a/drivers/infiniband/core/sa_query.c b/drivers/infiniband/core/sa_query.c index 1f91b6ed7ce8..f334090bb612 100644 --- a/drivers/infiniband/core/sa_query.c +++ b/drivers/infiniband/core/sa_query.c @@ -717,7 +717,9 @@ static int ib_nl_handle_set_timeout(struct sk_buff *skb, struct nlattr *tb[LS_NLA_TYPE_MAX]; int ret; - if (!netlink_capable(skb, CAP_NET_ADMIN)) + if (!(nlh->nlmsg_flags & NLM_F_REQUEST) || + !(NETLINK_CB(skb).sk) || + !netlink_capable(skb, CAP_NET_ADMIN)) return -EPERM; ret = nla_parse(tb, LS_NLA_TYPE_MAX - 1, nlmsg_data(nlh), @@ -791,7 +793,9 @@ static int ib_nl_handle_resolve_resp(struct sk_buff *skb, int found = 0; int ret; - if (!netlink_capable(skb, CAP_NET_ADMIN)) + if ((nlh->nlmsg_flags & NLM_F_REQUEST) || + !(NETLINK_CB(skb).sk) || + !netlink_capable(skb, CAP_NET_ADMIN)) return -EPERM; spin_lock_irqsave(&ib_nl_request_lock, flags); -- cgit v1.2.3-59-g8ed1b