[PATCH net 0/4] mptcp: Fix IPv6 reqsk ops and some netlink error codes

[PATCH net 0/4] mptcp: Fix IPv6 reqsk ops and some netlink error codes

[Mat Martineau]

Patch 1 adds some missing error status values for MPTCP path management
netlink commands with invalid attributes.

Patches 2-4 make IPv6 subflows use the correct request_sock_ops
structure and IPv6-specific destructor. The first patch in this group is
a prerequisite change that simplifies the last two patches.


Matthieu Baerts (3):
  mptcp: remove MPTCP 'ifdef' in TCP SYN cookies
  mptcp: dedicated request sock for subflow in v6
  mptcp: use proper req destructor for IPv6

Wei Yongjun (1):
  mptcp: netlink: fix some error return code

 include/net/mptcp.h      | 12 ++++++--
 net/ipv4/syncookies.c    |  7 ++---
 net/mptcp/pm_userspace.c |  4 +++
 net/mptcp/subflow.c      | 61 +++++++++++++++++++++++++++++++++-------
 4 files changed, 68 insertions(+), 16 deletions(-)


base-commit: 01de1123322e4fe1bbd0fcdf0982511b55519c03
-- 
2.38.1

[PATCH net 1/4] mptcp: netlink: fix some error return code

[Mat Martineau]

From: Wei Yongjun <weiyongjun1@huawei.com>

Fix to return negative error code -EINVAL from some error handling
case instead of 0, as done elsewhere in those functions.

Fixes: 9ab4807c84a4 ("mptcp: netlink: Add MPTCP_PM_CMD_ANNOUNCE")
Fixes: 702c2f646d42 ("mptcp: netlink: allow userspace-driven subflow establishment")
Cc: stable@vger.kernel.org
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm_userspace.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index 9e82250cbb70..0430415357ba 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -156,6 +156,7 @@ int mptcp_nl_cmd_announce(struct sk_buff *skb, struct genl_info *info)
 
 	if (addr_val.addr.id == 0 || !(addr_val.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
 		GENL_SET_ERR_MSG(info, "invalid addr id or flags");
+		err = -EINVAL;
 		goto announce_err;
 	}
 
@@ -282,6 +283,7 @@ int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info)
 
 	if (addr_l.id == 0) {
 		NL_SET_ERR_MSG_ATTR(info->extack, laddr, "missing local addr id");
+		err = -EINVAL;
 		goto create_err;
 	}
 
@@ -395,11 +397,13 @@ int mptcp_nl_cmd_sf_destroy(struct sk_buff *skb, struct genl_info *info)
 
 	if (addr_l.family != addr_r.family) {
 		GENL_SET_ERR_MSG(info, "address families do not match");
+		err = -EINVAL;
 		goto destroy_err;
 	}
 
 	if (!addr_l.port || !addr_r.port) {
 		GENL_SET_ERR_MSG(info, "missing local or remote port");
+		err = -EINVAL;
 		goto destroy_err;
 	}
 
-- 
2.38.1

[PATCH net 2/4] mptcp: remove MPTCP 'ifdef' in TCP SYN cookies

[Mat Martineau]

From: Matthieu Baerts <matthieu.baerts@tessares.net>

To ease the maintenance, it is often recommended to avoid having #ifdef
preprocessor conditions.

Here the section related to CONFIG_MPTCP was quite short but the next
commit needs to add more code around. It is then cleaner to move
specific MPTCP code to functions located in net/mptcp directory.

Now that mptcp_subflow_request_sock_ops structure can be static, it can
also be marked as "read only after init".

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 include/net/mptcp.h   | 12 ++++++++++--
 net/ipv4/syncookies.c |  7 +++----
 net/mptcp/subflow.c   | 12 +++++++++++-
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 412479ebf5ad..3c5c68618fcc 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -97,8 +97,6 @@ struct mptcp_out_options {
 };
 
 #ifdef CONFIG_MPTCP
-extern struct request_sock_ops mptcp_subflow_request_sock_ops;
-
 void mptcp_init(void);
 
 static inline bool sk_is_mptcp(const struct sock *sk)
@@ -188,6 +186,9 @@ void mptcp_seq_show(struct seq_file *seq);
 int mptcp_subflow_init_cookie_req(struct request_sock *req,
 				  const struct sock *sk_listener,
 				  struct sk_buff *skb);
+struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
+					       struct sock *sk_listener,
+					       bool attach_listener);
 
 __be32 mptcp_get_reset_option(const struct sk_buff *skb);
 
@@ -274,6 +275,13 @@ static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
 	return 0; /* TCP fallback */
 }
 
+static inline struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
+							     struct sock *sk_listener,
+							     bool attach_listener)
+{
+	return NULL;
+}
+
 static inline __be32 mptcp_reset_option(const struct sk_buff *skb)  { return htonl(0u); }
 #endif /* CONFIG_MPTCP */
 
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 942d2dfa1115..26fb97d1d4d9 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -288,12 +288,11 @@ struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops,
 	struct tcp_request_sock *treq;
 	struct request_sock *req;
 
-#ifdef CONFIG_MPTCP
 	if (sk_is_mptcp(sk))
-		ops = &mptcp_subflow_request_sock_ops;
-#endif
+		req = mptcp_subflow_reqsk_alloc(ops, sk, false);
+	else
+		req = inet_reqsk_alloc(ops, sk, false);
 
-	req = inet_reqsk_alloc(ops, sk, false);
 	if (!req)
 		return NULL;
 
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 2159b5f9988f..3f670f2d5c5c 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -529,7 +529,7 @@ static int subflow_v6_rebuild_header(struct sock *sk)
 }
 #endif
 
-struct request_sock_ops mptcp_subflow_request_sock_ops;
+static struct request_sock_ops mptcp_subflow_request_sock_ops __ro_after_init;
 static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops __ro_after_init;
 
 static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
@@ -582,6 +582,16 @@ static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 }
 #endif
 
+struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
+					       struct sock *sk_listener,
+					       bool attach_listener)
+{
+	ops = &mptcp_subflow_request_sock_ops;
+
+	return inet_reqsk_alloc(ops, sk_listener, attach_listener);
+}
+EXPORT_SYMBOL(mptcp_subflow_reqsk_alloc);
+
 /* validate hmac received in third ACK */
 static bool subflow_hmac_valid(const struct request_sock *req,
 			       const struct mptcp_options_received *mp_opt)
-- 
2.38.1

[PATCH net 3/4] mptcp: dedicated request sock for subflow in v6

[Mat Martineau]

From: Matthieu Baerts <matthieu.baerts@tessares.net>

tcp_request_sock_ops structure is specific to IPv4. It should then not
be used with MPTCP subflows on top of IPv6.

For example, it contains the 'family' field, initialised to AF_INET.
This 'family' field is used by TCP FastOpen code to generate the cookie
but also by TCP Metrics, SELinux and SYN Cookies. Using the wrong family
will not lead to crashes but displaying/using/checking wrong things.

Note that 'send_reset' callback from request_sock_ops structure is used
in some error paths. It is then also important to use the correct one
for IPv4 or IPv6.

The slab name can also be different in IPv4 and IPv6, it will be used
when printing some log messages. The slab pointer will anyway be the
same because the object size is the same for both v4 and v6. A
BUILD_BUG_ON() has also been added to make sure this size is the same.

Fixes: cec37a6e41aa ("mptcp: Handle MP_CAPABLE options for outgoing connections")
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---

Note: One original author of cec37a6e41aa is not cc'd due to inactive
email address.

---
 net/mptcp/subflow.c | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 3f670f2d5c5c..30524dd7d0ec 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -529,7 +529,7 @@ static int subflow_v6_rebuild_header(struct sock *sk)
 }
 #endif
 
-static struct request_sock_ops mptcp_subflow_request_sock_ops __ro_after_init;
+static struct request_sock_ops mptcp_subflow_v4_request_sock_ops __ro_after_init;
 static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops __ro_after_init;
 
 static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
@@ -542,7 +542,7 @@ static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 	if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
 		goto drop;
 
-	return tcp_conn_request(&mptcp_subflow_request_sock_ops,
+	return tcp_conn_request(&mptcp_subflow_v4_request_sock_ops,
 				&subflow_request_sock_ipv4_ops,
 				sk, skb);
 drop:
@@ -551,6 +551,7 @@ static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 }
 
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static struct request_sock_ops mptcp_subflow_v6_request_sock_ops __ro_after_init;
 static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops __ro_after_init;
 static struct inet_connection_sock_af_ops subflow_v6_specific __ro_after_init;
 static struct inet_connection_sock_af_ops subflow_v6m_specific __ro_after_init;
@@ -573,7 +574,7 @@ static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 		return 0;
 	}
 
-	return tcp_conn_request(&mptcp_subflow_request_sock_ops,
+	return tcp_conn_request(&mptcp_subflow_v6_request_sock_ops,
 				&subflow_request_sock_ipv6_ops, sk, skb);
 
 drop:
@@ -586,7 +587,12 @@ struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *op
 					       struct sock *sk_listener,
 					       bool attach_listener)
 {
-	ops = &mptcp_subflow_request_sock_ops;
+	if (ops->family == AF_INET)
+		ops = &mptcp_subflow_v4_request_sock_ops;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	else if (ops->family == AF_INET6)
+		ops = &mptcp_subflow_v6_request_sock_ops;
+#endif
 
 	return inet_reqsk_alloc(ops, sk_listener, attach_listener);
 }
@@ -1914,7 +1920,6 @@ static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = {
 static int subflow_ops_init(struct request_sock_ops *subflow_ops)
 {
 	subflow_ops->obj_size = sizeof(struct mptcp_subflow_request_sock);
-	subflow_ops->slab_name = "request_sock_subflow";
 
 	subflow_ops->slab = kmem_cache_create(subflow_ops->slab_name,
 					      subflow_ops->obj_size, 0,
@@ -1931,9 +1936,10 @@ static int subflow_ops_init(struct request_sock_ops *subflow_ops)
 
 void __init mptcp_subflow_init(void)
 {
-	mptcp_subflow_request_sock_ops = tcp_request_sock_ops;
-	if (subflow_ops_init(&mptcp_subflow_request_sock_ops) != 0)
-		panic("MPTCP: failed to init subflow request sock ops\n");
+	mptcp_subflow_v4_request_sock_ops = tcp_request_sock_ops;
+	mptcp_subflow_v4_request_sock_ops.slab_name = "request_sock_subflow_v4";
+	if (subflow_ops_init(&mptcp_subflow_v4_request_sock_ops) != 0)
+		panic("MPTCP: failed to init subflow v4 request sock ops\n");
 
 	subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops;
 	subflow_request_sock_ipv4_ops.route_req = subflow_v4_route_req;
@@ -1948,6 +1954,18 @@ void __init mptcp_subflow_init(void)
 	tcp_prot_override.release_cb = tcp_release_cb_override;
 
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	/* In struct mptcp_subflow_request_sock, we assume the TCP request sock
+	 * structures for v4 and v6 have the same size. It should not changed in
+	 * the future but better to make sure to be warned if it is no longer
+	 * the case.
+	 */
+	BUILD_BUG_ON(sizeof(struct tcp_request_sock) != sizeof(struct tcp6_request_sock));
+
+	mptcp_subflow_v6_request_sock_ops = tcp6_request_sock_ops;
+	mptcp_subflow_v6_request_sock_ops.slab_name = "request_sock_subflow_v6";
+	if (subflow_ops_init(&mptcp_subflow_v6_request_sock_ops) != 0)
+		panic("MPTCP: failed to init subflow v6 request sock ops\n");
+
 	subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops;
 	subflow_request_sock_ipv6_ops.route_req = subflow_v6_route_req;
 
-- 
2.38.1

[PATCH net 4/4] mptcp: use proper req destructor for IPv6

[Mat Martineau]

From: Matthieu Baerts <matthieu.baerts@tessares.net>

Before, only the destructor from TCP request sock in IPv4 was called
even if the subflow was IPv6.

It is important to use the right destructor to avoid memory leaks with
some advanced IPv6 features, e.g. when the request socks contain
specific IPv6 options.

Fixes: 79c0949e9a09 ("mptcp: Add key generation and token tree")
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---

Note: One original author of 79c0949e9a09 is not cc'd due to inactive
email address.

---
 net/mptcp/subflow.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 30524dd7d0ec..613f515fedf0 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -45,7 +45,6 @@ static void subflow_req_destructor(struct request_sock *req)
 		sock_put((struct sock *)subflow_req->msk);
 
 	mptcp_token_destroy_request(req);
-	tcp_request_sock_ops.destructor(req);
 }
 
 static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
@@ -550,6 +549,12 @@ static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 	return 0;
 }
 
+static void subflow_v4_req_destructor(struct request_sock *req)
+{
+	subflow_req_destructor(req);
+	tcp_request_sock_ops.destructor(req);
+}
+
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 static struct request_sock_ops mptcp_subflow_v6_request_sock_ops __ro_after_init;
 static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops __ro_after_init;
@@ -581,6 +586,12 @@ static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 	tcp_listendrop(sk);
 	return 0; /* don't send reset */
 }
+
+static void subflow_v6_req_destructor(struct request_sock *req)
+{
+	subflow_req_destructor(req);
+	tcp6_request_sock_ops.destructor(req);
+}
 #endif
 
 struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
@@ -1929,8 +1940,6 @@ static int subflow_ops_init(struct request_sock_ops *subflow_ops)
 	if (!subflow_ops->slab)
 		return -ENOMEM;
 
-	subflow_ops->destructor = subflow_req_destructor;
-
 	return 0;
 }
 
@@ -1938,6 +1947,8 @@ void __init mptcp_subflow_init(void)
 {
 	mptcp_subflow_v4_request_sock_ops = tcp_request_sock_ops;
 	mptcp_subflow_v4_request_sock_ops.slab_name = "request_sock_subflow_v4";
+	mptcp_subflow_v4_request_sock_ops.destructor = subflow_v4_req_destructor;
+
 	if (subflow_ops_init(&mptcp_subflow_v4_request_sock_ops) != 0)
 		panic("MPTCP: failed to init subflow v4 request sock ops\n");
 
@@ -1963,6 +1974,8 @@ void __init mptcp_subflow_init(void)
 
 	mptcp_subflow_v6_request_sock_ops = tcp6_request_sock_ops;
 	mptcp_subflow_v6_request_sock_ops.slab_name = "request_sock_subflow_v6";
+	mptcp_subflow_v6_request_sock_ops.destructor = subflow_v6_req_destructor;
+
 	if (subflow_ops_init(&mptcp_subflow_v6_request_sock_ops) != 0)
 		panic("MPTCP: failed to init subflow v6 request sock ops\n");
 
-- 
2.38.1

Re: [PATCH net 0/4] mptcp: Fix IPv6 reqsk ops and some netlink error codes

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Fri,  9 Dec 2022 16:28:06 -0800 you wrote:
> Patch 1 adds some missing error status values for MPTCP path management
> netlink commands with invalid attributes.
> 
> Patches 2-4 make IPv6 subflows use the correct request_sock_ops
> structure and IPv6-specific destructor. The first patch in this group is
> a prerequisite change that simplifies the last two patches.
> 
> [...]

Here is the summary with links:
  - [net,1/4] mptcp: netlink: fix some error return code
    https://git.kernel.org/netdev/net/c/e0fe1123ab2b
  - [net,2/4] mptcp: remove MPTCP 'ifdef' in TCP SYN cookies
    https://git.kernel.org/netdev/net/c/3fff88186f04
  - [net,3/4] mptcp: dedicated request sock for subflow in v6
    https://git.kernel.org/netdev/net/c/34b21d1ddc8a
  - [net,4/4] mptcp: use proper req destructor for IPv6
    https://git.kernel.org/netdev/net/c/d3295fee3c75

You are awesome, thank you!
-- 
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