From bf8b79e444a748963c71d2a58709e1ce5597e1b5 Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Fri, 4 Aug 2006 23:03:29 -0700 Subject: [PATCH] [NETLINK]: Convert core netlink handling to new netlink api Fixes a theoretical memory and locking leak when the size of the netlink header would exceed the skb tailroom. Signed-off-by: Thomas Graf Signed-off-by: David S. Miller --- net/netlink/af_netlink.c | 41 +++++++++++++++++++++------------------- 1 file changed, 22 insertions(+), 19 deletions(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 8b85036ba8e3..0f36ddc0b72d 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1147,7 +1147,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock, if (len > sk->sk_sndbuf - 32) goto out; err = -ENOBUFS; - skb = alloc_skb(len, GFP_KERNEL); + skb = nlmsg_new(len, GFP_KERNEL); if (skb==NULL) goto out; @@ -1341,19 +1341,18 @@ static int netlink_dump(struct sock *sk) struct netlink_callback *cb; struct sk_buff *skb; struct nlmsghdr *nlh; - int len; + int len, err = -ENOBUFS; skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL); if (!skb) - return -ENOBUFS; + goto errout; spin_lock(&nlk->cb_lock); cb = nlk->cb; if (cb == NULL) { - spin_unlock(&nlk->cb_lock); - kfree_skb(skb); - return -EINVAL; + err = -EINVAL; + goto errout_skb; } len = cb->dump(skb, cb); @@ -1365,8 +1364,12 @@ static int netlink_dump(struct sock *sk) return 0; } - nlh = NLMSG_NEW_ANSWER(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI); - memcpy(NLMSG_DATA(nlh), &len, sizeof(len)); + nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI); + if (!nlh) + goto errout_skb; + + memcpy(nlmsg_data(nlh), &len, sizeof(len)); + skb_queue_tail(&sk->sk_receive_queue, skb); sk->sk_data_ready(sk, skb->len); @@ -1378,8 +1381,11 @@ static int netlink_dump(struct sock *sk) netlink_destroy_callback(cb); return 0; -nlmsg_failure: - return -ENOBUFS; +errout_skb: + spin_unlock(&nlk->cb_lock); + kfree_skb(skb); +errout: + return err; } int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, @@ -1431,11 +1437,11 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) int size; if (err == 0) - size = NLMSG_SPACE(sizeof(struct nlmsgerr)); + size = nlmsg_total_size(sizeof(*errmsg)); else - size = NLMSG_SPACE(4 + NLMSG_ALIGN(nlh->nlmsg_len)); + size = nlmsg_total_size(sizeof(*errmsg) + nlmsg_len(nlh)); - skb = alloc_skb(size, GFP_KERNEL); + skb = nlmsg_new(size, GFP_KERNEL); if (!skb) { struct sock *sk; @@ -1451,16 +1457,15 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, NLMSG_ERROR, sizeof(struct nlmsgerr), 0); - errmsg = NLMSG_DATA(rep); + errmsg = nlmsg_data(rep); errmsg->error = err; - memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(struct nlmsghdr)); + memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh)); netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT); } static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, struct nlmsghdr *, int *)) { - unsigned int total_len; struct nlmsghdr *nlh; int err; @@ -1470,8 +1475,6 @@ static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) return 0; - total_len = min(NLMSG_ALIGN(nlh->nlmsg_len), skb->len); - if (cb(skb, nlh, &err) < 0) { /* Not an error, but we have to interrupt processing * here. Note: that in this case we do not pull @@ -1483,7 +1486,7 @@ static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, } else if (nlh->nlmsg_flags & NLM_F_ACK) netlink_ack(skb, nlh, 0); - skb_pull(skb, total_len); + netlink_queue_skip(nlh, skb); } return 0; -- 2.30.2