2010-07-29 11:59:39

by Dmitry Popov

Subject: [PATCH] tcp: cookie transactions setsockopt memory leak

From: Dmitry Popov <[email protected]>

There is a bug in do_tcp_setsockopt(net/ipv4/tcp.c),
TCP_COOKIE_TRANSACTIONS case.
In some cases (when tp->cookie_values == NULL) new tcp_cookie_values
structure can be allocated (at cvp), but not bound to
tp->cookie_values. So a memory leak occurs.

Signed-off-by: Dmitry Popov <[email protected]>
---
tp->cookie_values can be NULL if socket was initialized with
sysctl_tcp_cookie_size == 0 (tcp_v4_init_sock, net/ipv4/tcp_ipv4.c)
Buggy releases: 2.6.33+ (since commit e56fb50f2b7958b931c8a2fc0966061b3f3c8f3a)

?net/ipv4/tcp.c | ? ?7 +++++--
?1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 83d0213..9c490a1 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2179,6 +2179,8 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
GFP_KERNEL);
if (cvp == NULL)
return -ENOMEM;
+
+ kref_init(&cvp->kref);
}
lock_sock(sk);
tp->rx_opt.cookie_in_always =
@@ -2193,12 +2195,11 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
*/
kref_put(&tp->cookie_values->kref,
tcp_cookie_values_release);
- kref_init(&cvp->kref);
- tp->cookie_values = cvp;
} else {
cvp = tp->cookie_values;
}
}
+
if (cvp != NULL) {
cvp->cookie_desired = ctd.tcpct_cookie_desired;

@@ -2212,6 +2213,8 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
cvp->s_data_desired = ctd.tcpct_s_data_desired;
cvp->s_data_constant = 0; /* false */
}
+
+ tp->cookie_values = cvp;
}
release_sock(sk);
return err;

2010-07-31 06:05:09

by David Miller

Subject: Re: [PATCH] tcp: cookie transactions setsockopt memory leak

From: Dmitry Popov <[email protected]>
Date: Thu, 29 Jul 2010 15:59:36 +0400

> From: Dmitry Popov <[email protected]>
>
> There is a bug in do_tcp_setsockopt(net/ipv4/tcp.c),
> TCP_COOKIE_TRANSACTIONS case.
> In some cases (when tp->cookie_values == NULL) new tcp_cookie_values
> structure can be allocated (at cvp), but not bound to
> tp->cookie_values. So a memory leak occurs.
>
> Signed-off-by: Dmitry Popov <[email protected]>

Applied and queued up for -stable, thanks Dmitry.