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Message-ID: <1426027533.11398.18.camel@edumazet-glaptop2.roam.corp.google.com>
Date: Tue, 10 Mar 2015 15:45:33 -0700
From: Eric Dumazet <eric.dumazet@...il.com>
To: David Miller <davem@...emloft.net>
Cc: netdev <netdev@...r.kernel.org>, Eric Salo <salo@...gle.com>
Subject: [PATCH net-next] net: add real socket cookies
From: Eric Dumazet <edumazet@...gle.com>
A long standing problem in netlink socket dumps is the use
of kernel socket addresses as cookies.
1) It is a security concern.
2) Sockets can be reused quite quickly, so there is
no guarantee a cookie is used once and identify
a flow.
3) request sock, establish sock, and timewait socks
for a given flow have different cookies.
Part of our effort to bring better TCP statistics requires
to switch to a different allocator.
In this patch, I chose to use a per network namespace 64bit generator,
and to use it only in the case a socket needs to be dumped to netlink.
Note that I tried to carry cookies from request sock, to establish sock,
then timewait sockets.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Cc: Eric Salo <salo@...gle.com>
---
include/linux/sock_diag.h | 4 +--
include/net/inet_sock.h | 2 +
include/net/inet_timewait_sock.h | 1
include/net/net_namespace.h | 2 +
include/net/sock.h | 3 ++
net/core/sock.c | 1
net/core/sock_diag.c | 37 +++++++++++++++++++++--------
net/dccp/ipv4.c | 2 +
net/ipv4/inet_connection_sock.c | 3 +-
net/ipv4/inet_diag.c | 14 +++++++---
net/ipv4/inet_timewait_sock.c | 1
net/ipv4/syncookies.c | 1
net/ipv4/tcp_input.c | 2 +
13 files changed, 55 insertions(+), 18 deletions(-)
diff --git a/include/linux/sock_diag.h b/include/linux/sock_diag.h
index b5ad7d35a636..083ac388098e 100644
--- a/include/linux/sock_diag.h
+++ b/include/linux/sock_diag.h
@@ -19,8 +19,8 @@ void sock_diag_unregister(const struct sock_diag_handler *h);
void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh));
void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh));
-int sock_diag_check_cookie(void *sk, const __u32 *cookie);
-void sock_diag_save_cookie(void *sk, __u32 *cookie);
+int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie);
+void sock_diag_save_cookie(struct sock *sk, __u32 *cookie);
int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attr);
int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk,
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index eb16c7beed1e..e565afdc14ad 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -77,6 +77,8 @@ struct inet_request_sock {
#define ir_v6_rmt_addr req.__req_common.skc_v6_daddr
#define ir_v6_loc_addr req.__req_common.skc_v6_rcv_saddr
#define ir_iif req.__req_common.skc_bound_dev_if
+#define ir_cookie req.__req_common.skc_cookie
+#define ireq_net req.__req_common.skc_net
kmemcheck_bitfield_begin(flags);
u16 snd_wscale : 4,
diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h
index 6c566034e26d..b7ce1003c429 100644
--- a/include/net/inet_timewait_sock.h
+++ b/include/net/inet_timewait_sock.h
@@ -122,6 +122,7 @@ struct inet_timewait_sock {
#define tw_v6_rcv_saddr __tw_common.skc_v6_rcv_saddr
#define tw_dport __tw_common.skc_dport
#define tw_num __tw_common.skc_num
+#define tw_cookie __tw_common.skc_cookie
int tw_timeout;
volatile unsigned char tw_substate;
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 2cb9acb618e9..e086f4030dd2 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -56,6 +56,8 @@ struct net {
#endif
spinlock_t rules_mod_lock;
+ atomic64_t cookie_gen;
+
struct list_head list; /* list of network namespaces */
struct list_head cleanup_list; /* namespaces on death row */
struct list_head exit_list; /* Use only net_mutex */
diff --git a/include/net/sock.h b/include/net/sock.h
index 250822cc1e02..d996c633bec2 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -199,6 +199,8 @@ struct sock_common {
struct in6_addr skc_v6_rcv_saddr;
#endif
+ atomic64_t skc_cookie;
+
/*
* fields between dontcopy_begin/dontcopy_end
* are not copied in sock_copy()
@@ -329,6 +331,7 @@ struct sock {
#define sk_net __sk_common.skc_net
#define sk_v6_daddr __sk_common.skc_v6_daddr
#define sk_v6_rcv_saddr __sk_common.skc_v6_rcv_saddr
+#define sk_cookie __sk_common.skc_cookie
socket_lock_t sk_lock;
struct sk_buff_head sk_receive_queue;
diff --git a/net/core/sock.c b/net/core/sock.c
index 726e1f99aa8d..a9a9c2ff9260 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1538,6 +1538,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
newsk->sk_err = 0;
newsk->sk_priority = 0;
newsk->sk_incoming_cpu = raw_smp_processor_id();
+ atomic64_set(&newsk->sk_cookie, 0);
/*
* Before updating sk_refcnt, we must commit prior changes to memory
* (Documentation/RCU/rculist_nulls.txt for details)
diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index 96e70ee05a8d..74dddf84adcd 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -13,22 +13,39 @@ static const struct sock_diag_handler *sock_diag_handlers[AF_MAX];
static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh);
static DEFINE_MUTEX(sock_diag_table_mutex);
-int sock_diag_check_cookie(void *sk, const __u32 *cookie)
+static u64 sock_gen_cookie(struct sock *sk)
{
- if ((cookie[0] != INET_DIAG_NOCOOKIE ||
- cookie[1] != INET_DIAG_NOCOOKIE) &&
- ((u32)(unsigned long)sk != cookie[0] ||
- (u32)((((unsigned long)sk) >> 31) >> 1) != cookie[1]))
- return -ESTALE;
- else
+ while (1) {
+ u64 res = atomic64_read(&sk->sk_cookie);
+
+ if (res)
+ return res;
+ res = atomic64_inc_return(&sock_net(sk)->cookie_gen);
+ atomic64_cmpxchg(&sk->sk_cookie, 0, res);
+ }
+}
+
+int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie)
+{
+ u64 res;
+
+ if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE)
return 0;
+
+ res = sock_gen_cookie(sk);
+ if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1])
+ return -ESTALE;
+
+ return 0;
}
EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
-void sock_diag_save_cookie(void *sk, __u32 *cookie)
+void sock_diag_save_cookie(struct sock *sk, __u32 *cookie)
{
- cookie[0] = (u32)(unsigned long)sk;
- cookie[1] = (u32)(((unsigned long)sk >> 31) >> 1);
+ u64 res = sock_gen_cookie(sk);
+
+ cookie[0] = (u32)res;
+ cookie[1] = (u32)(res >> 32);
}
EXPORT_SYMBOL_GPL(sock_diag_save_cookie);
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index e45b968613a4..207281ae3536 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -641,6 +641,8 @@ int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
ireq = inet_rsk(req);
ireq->ir_loc_addr = ip_hdr(skb)->daddr;
ireq->ir_rmt_addr = ip_hdr(skb)->saddr;
+ ireq->ireq_net = sock_net(sk);
+ atomic64_set(&ireq->ir_cookie, 0);
/*
* Step 3: Process LISTEN state
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 14d02ea905b6..a097ae38b639 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -678,7 +678,8 @@ struct sock *inet_csk_clone_lock(const struct sock *sk,
newsk->sk_write_space = sk_stream_write_space;
newsk->sk_mark = inet_rsk(req)->ir_mark;
-
+ atomic64_cmpxchg(&newsk->sk_cookie, 0,
+ atomic64_read(&inet_rsk(req)->ir_cookie));
newicsk->icsk_retransmits = 0;
newicsk->icsk_backoff = 0;
newicsk->icsk_probes_out = 0;
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index ac3bfb458afd..29317ff4a007 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -221,12 +221,13 @@ static int inet_csk_diag_fill(struct sock *sk,
user_ns, portid, seq, nlmsg_flags, unlh);
}
-static int inet_twsk_diag_fill(struct inet_timewait_sock *tw,
+static int inet_twsk_diag_fill(struct sock *sk,
struct sk_buff *skb,
const struct inet_diag_req_v2 *req,
u32 portid, u32 seq, u16 nlmsg_flags,
const struct nlmsghdr *unlh)
{
+ struct inet_timewait_sock *tw = inet_twsk(sk);
struct inet_diag_msg *r;
struct nlmsghdr *nlh;
s32 tmo;
@@ -247,7 +248,7 @@ static int inet_twsk_diag_fill(struct inet_timewait_sock *tw,
r->idiag_retrans = 0;
r->id.idiag_if = tw->tw_bound_dev_if;
- sock_diag_save_cookie(tw, r->id.idiag_cookie);
+ sock_diag_save_cookie(sk, r->id.idiag_cookie);
r->id.idiag_sport = tw->tw_sport;
r->id.idiag_dport = tw->tw_dport;
@@ -283,7 +284,7 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
const struct nlmsghdr *unlh)
{
if (sk->sk_state == TCP_TIME_WAIT)
- return inet_twsk_diag_fill(inet_twsk(sk), skb, r, portid, seq,
+ return inet_twsk_diag_fill(sk, skb, r, portid, seq,
nlmsg_flags, unlh);
return inet_csk_diag_fill(sk, skb, r, user_ns, portid, seq,
@@ -675,7 +676,7 @@ static int inet_twsk_diag_dump(struct sock *sk,
if (!inet_diag_bc_sk(bc, sk))
return 0;
- return inet_twsk_diag_fill(inet_twsk(sk), skb, r,
+ return inet_twsk_diag_fill(sk, skb, r,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, NLM_F_MULTI, cb->nlh);
}
@@ -734,7 +735,10 @@ static int inet_diag_fill_req(struct sk_buff *skb, struct sock *sk,
r->idiag_retrans = req->num_retrans;
r->id.idiag_if = sk->sk_bound_dev_if;
- sock_diag_save_cookie(req, r->id.idiag_cookie);
+
+ BUILD_BUG_ON(offsetof(struct inet_request_sock, ir_cookie) !=
+ offsetof(struct sock, sk_cookie));
+ sock_diag_save_cookie((struct sock *)ireq, r->id.idiag_cookie);
tmo = req->expires - jiffies;
if (tmo < 0)
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 6d592f8555fb..2bd980526631 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -195,6 +195,7 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, const int stat
tw->tw_ipv6only = 0;
tw->tw_transparent = inet->transparent;
tw->tw_prot = sk->sk_prot_creator;
+ atomic64_set(&tw->tw_cookie, atomic64_read(&sk->sk_cookie));
twsk_net_set(tw, hold_net(sock_net(sk)));
/*
* Because we use RCU lookups, we should not set tw_refcnt
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 45fe60c5238e..ece31b426013 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -346,6 +346,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
req->ts_recent = tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0;
treq->snt_synack = tcp_opt.saw_tstamp ? tcp_opt.rcv_tsecr : 0;
treq->listener = NULL;
+ ireq->ireq_net = sock_net(sk);
/* We throwed the options of the initial SYN away, so we hope
* the ACK carries the same options again (see RFC1122 4.2.3.8)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index fb4cf8b8e121..d7045f5f6ebf 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5965,6 +5965,8 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
tcp_openreq_init(req, &tmp_opt, skb, sk);
+ inet_rsk(req)->ireq_net = sock_net(sk);
+ atomic64_set(&inet_rsk(req)->ir_cookie, 0);
af_ops->init_req(req, sk, skb);
--
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