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>
diff --git a/net/ipv4/tcp_illinois.c b/net/ipv4/tcp_illinois.c
index 1d5a30a..67476f0 100644
--- a/net/ipv4/tcp_illinois.c
+++ b/net/ipv4/tcp_illinois.c
@@ -300,8 +300,7 @@
}
/* Extract info for Tcp socket info provided via netlink. */
-static void tcp_illinois_info(struct sock *sk, u32 ext,
- struct sk_buff *skb)
+static int tcp_illinois_info(struct sock *sk, u32 ext, struct sk_buff *skb)
{
const struct illinois *ca = inet_csk_ca(sk);
@@ -318,8 +317,9 @@
do_div(t, info.tcpv_rttcnt);
info.tcpv_rtt = t;
}
- nla_put(skb, INET_DIAG_VEGASINFO, sizeof(info), &info);
+ return nla_put(skb, INET_DIAG_VEGASINFO, sizeof(info), &info);
}
+ return 0;
}
static struct tcp_congestion_ops tcp_illinois __read_mostly = {