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authorEric Dumazet <edumazet@google.com>2015-04-16 18:10:35 -0700
committerDavid S. Miller <davem@davemloft.net>2015-04-17 13:28:31 -0400
commit521f1cf1dbb9d5ad858dca5dc75d1b45f64b6589 (patch)
tree2c6276958f5d7348616d887f4a64f5b78ec6b9ef /net/ipv4/inet_diag.c
parenttcp: tcp_get_info() should fetch socket fields once (diff)
downloadlinux-dev-521f1cf1dbb9d5ad858dca5dc75d1b45f64b6589.tar.xz
linux-dev-521f1cf1dbb9d5ad858dca5dc75d1b45f64b6589.zip
inet_diag: fix access to tcp cc information
Two different problems are fixed here : 1) inet_sk_diag_fill() might be called without socket lock held. icsk->icsk_ca_ops can change under us and module be unloaded. -> Access to freed memory. Fix this using rcu_read_lock() to prevent module unload. 2) Some TCP Congestion Control modules provide information but again this is not safe against icsk->icsk_ca_ops change and nla_put() errors were ignored. Some sockets could not get the additional info if skb was almost full. Fix this by returning a status from get_info() handlers and using rcu protection as well. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/inet_diag.c')
-rw-r--r--net/ipv4/inet_diag.c28
1 files changed, 22 insertions, 6 deletions
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 70e8b3c308ec..bb77ebdae3b3 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -111,6 +111,7 @@ int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk,
const struct nlmsghdr *unlh)
{
const struct inet_sock *inet = inet_sk(sk);
+ const struct tcp_congestion_ops *ca_ops;
const struct inet_diag_handler *handler;
int ext = req->idiag_ext;
struct inet_diag_msg *r;
@@ -208,16 +209,31 @@ int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk,
info = nla_data(attr);
}
- if ((ext & (1 << (INET_DIAG_CONG - 1))) && icsk->icsk_ca_ops)
- if (nla_put_string(skb, INET_DIAG_CONG,
- icsk->icsk_ca_ops->name) < 0)
+ if (ext & (1 << (INET_DIAG_CONG - 1))) {
+ int err = 0;
+
+ rcu_read_lock();
+ ca_ops = READ_ONCE(icsk->icsk_ca_ops);
+ if (ca_ops)
+ err = nla_put_string(skb, INET_DIAG_CONG, ca_ops->name);
+ rcu_read_unlock();
+ if (err < 0)
goto errout;
+ }
handler->idiag_get_info(sk, r, info);
- if (sk->sk_state < TCP_TIME_WAIT &&
- icsk->icsk_ca_ops && icsk->icsk_ca_ops->get_info)
- icsk->icsk_ca_ops->get_info(sk, ext, skb);
+ if (sk->sk_state < TCP_TIME_WAIT) {
+ int err = 0;
+
+ rcu_read_lock();
+ ca_ops = READ_ONCE(icsk->icsk_ca_ops);
+ if (ca_ops && ca_ops->get_info)
+ err = ca_ops->get_info(sk, ext, skb);
+ rcu_read_unlock();
+ if (err < 0)
+ goto errout;
+ }
out:
nlmsg_end(skb, nlh);