From 41dd9596d6b239a125c3d19f9d0ca90bdbfbf876 Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@strlen.de>
Date: Mon, 30 Nov 2020 16:36:29 +0100
Subject: [PATCH 1/3] security: add const qualifier to struct sock in various
places
A followup change to tcp_request_sock_op would have to drop the 'const'
qualifier from the 'route_req' function as the
'security_inet_conn_request' call is moved there - and that function
expects a 'struct sock *'.
However, it turns out its also possible to add a const qualifier to
security_inet_conn_request instead.
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
include/linux/lsm_audit.h | 2 +-
include/linux/lsm_hook_defs.h | 2 +-
include/linux/security.h | 4 ++--
security/apparmor/include/net.h | 2 +-
security/apparmor/lsm.c | 2 +-
security/apparmor/net.c | 6 +++---
security/lsm_audit.c | 4 ++--
security/security.c | 2 +-
security/selinux/hooks.c | 2 +-
security/smack/smack_lsm.c | 4 ++--
10 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
index 28f23b341c1c..cd23355d2271 100644
--- a/include/linux/lsm_audit.h
+++ b/include/linux/lsm_audit.h
@@ -26,7 +26,7 @@
struct lsm_network_audit {
int netif;
- struct sock *sk;
+ const struct sock *sk;
u16 family;
__be16 dport;
__be16 sport;
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 32a940117e7a..acc0494cceba 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -301,7 +301,7 @@ LSM_HOOK(void, LSM_RET_VOID, sk_clone_security, const struct sock *sk,
struct sock *newsk)
LSM_HOOK(void, LSM_RET_VOID, sk_getsecid, struct sock *sk, u32 *secid)
LSM_HOOK(void, LSM_RET_VOID, sock_graft, struct sock *sk, struct socket *parent)
-LSM_HOOK(int, 0, inet_conn_request, struct sock *sk, struct sk_buff *skb,
+LSM_HOOK(int, 0, inet_conn_request, const struct sock *sk, struct sk_buff *skb,
struct request_sock *req)
LSM_HOOK(void, LSM_RET_VOID, inet_csk_clone, struct sock *newsk,
const struct request_sock *req)
diff --git a/include/linux/security.h b/include/linux/security.h
index bc2725491560..0df62735651b 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1358,7 +1358,7 @@ void security_sk_clone(const struct sock *sk, struct sock *newsk);
void security_sk_classify_flow(struct sock *sk, struct flowi *fl);
void security_req_classify_flow(const struct request_sock *req, struct flowi *fl);
void security_sock_graft(struct sock*sk, struct socket *parent);
-int security_inet_conn_request(struct sock *sk,
+int security_inet_conn_request(const struct sock *sk,
struct sk_buff *skb, struct request_sock *req);
void security_inet_csk_clone(struct sock *newsk,
const struct request_sock *req);
@@ -1519,7 +1519,7 @@ static inline void security_sock_graft(struct sock *sk, struct socket *parent)
{
}
-static inline int security_inet_conn_request(struct sock *sk,
+static inline int security_inet_conn_request(const struct sock *sk,
struct sk_buff *skb, struct request_sock *req)
{
return 0;
diff --git a/security/apparmor/include/net.h b/security/apparmor/include/net.h
index 2431c011800d..aadb4b29fb66 100644
--- a/security/apparmor/include/net.h
+++ b/security/apparmor/include/net.h
@@ -107,6 +107,6 @@ int aa_sock_file_perm(struct aa_label *label, const char *op, u32 request,
struct socket *sock);
int apparmor_secmark_check(struct aa_label *label, char *op, u32 request,
- u32 secid, struct sock *sk);
+ u32 secid, const struct sock *sk);
#endif /* __AA_NET_H */
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index ffeaee5ed968..1b0aba8eb723 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -1147,7 +1147,7 @@ static void apparmor_sock_graft(struct sock *sk, struct socket *parent)
}
#ifdef CONFIG_NETWORK_SECMARK
-static int apparmor_inet_conn_request(struct sock *sk, struct sk_buff *skb,
+static int apparmor_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
struct request_sock *req)
{
struct aa_sk_ctx *ctx = SK_CTX(sk);
diff --git a/security/apparmor/net.c b/security/apparmor/net.c
index fa0e85568450..e0c1b50d6edd 100644
--- a/security/apparmor/net.c
+++ b/security/apparmor/net.c
@@ -211,7 +211,7 @@ static int apparmor_secmark_init(struct aa_secmark *secmark)
}
static int aa_secmark_perm(struct aa_profile *profile, u32 request, u32 secid,
- struct common_audit_data *sa, struct sock *sk)
+ struct common_audit_data *sa)
{
int i, ret;
struct aa_perms perms = { };
@@ -244,13 +244,13 @@ static int aa_secmark_perm(struct aa_profile *profile, u32 request, u32 secid,
}
int apparmor_secmark_check(struct aa_label *label, char *op, u32 request,
- u32 secid, struct sock *sk)
+ u32 secid, const struct sock *sk)
{
struct aa_profile *profile;
DEFINE_AUDIT_SK(sa, op, sk);
return fn_for_each_confined(label, profile,
aa_secmark_perm(profile, request, secid,
- &sa, sk));
+ &sa));
}
#endif
diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index 53d0d183db8f..078f9cdcd7f5 100644
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
@@ -183,7 +183,7 @@ int ipv6_skb_to_auditdata(struct sk_buff *skb,
static inline void print_ipv6_addr(struct audit_buffer *ab,
- struct in6_addr *addr, __be16 port,
+ const struct in6_addr *addr, __be16 port,
char *name1, char *name2)
{
if (!ipv6_addr_any(addr))
@@ -322,7 +322,7 @@ static void dump_common_audit_data(struct audit_buffer *ab,
}
case LSM_AUDIT_DATA_NET:
if (a->u.net->sk) {
- struct sock *sk = a->u.net->sk;
+ const struct sock *sk = a->u.net->sk;
struct unix_sock *u;
struct unix_address *addr;
int len = 0;
diff --git a/security/security.c b/security/security.c
index a28045dc9e7f..6509f95d203f 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2225,7 +2225,7 @@ void security_sock_graft(struct sock *sk, struct socket *parent)
}
EXPORT_SYMBOL(security_sock_graft);
-int security_inet_conn_request(struct sock *sk,
+int security_inet_conn_request(const struct sock *sk,
struct sk_buff *skb, struct request_sock *req)
{
return call_int_hook(inet_conn_request, 0, sk, skb, req);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 6b1826fc3658..6fa593006802 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5355,7 +5355,7 @@ static void selinux_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk,
selinux_netlbl_sctp_sk_clone(sk, newsk);
}
-static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
+static int selinux_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
struct request_sock *req)
{
struct sk_security_struct *sksec = sk->sk_security;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 5c90b9fa4d40..3a62d6aa74a6 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3864,7 +3864,7 @@ static inline struct smack_known *smack_from_skb(struct sk_buff *skb)
*
* Returns smack_known of the IP options or NULL if that won't work.
*/
-static struct smack_known *smack_from_netlbl(struct sock *sk, u16 family,
+static struct smack_known *smack_from_netlbl(const struct sock *sk, u16 family,
struct sk_buff *skb)
{
struct netlbl_lsm_secattr secattr;
@@ -4114,7 +4114,7 @@ static void smack_sock_graft(struct sock *sk, struct socket *parent)
* Returns 0 if a task with the packet label could write to
* the socket, otherwise an error code
*/
-static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
+static int smack_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
struct request_sock *req)
{
u16 family = sk->sk_family;
From 7ea851d19b23593d7601ecb8091d529f4f475bf5 Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@strlen.de>
Date: Mon, 30 Nov 2020 16:36:30 +0100
Subject: [PATCH 2/3] tcp: merge 'init_req' and 'route_req' functions
The Multipath-TCP standard (RFC 8684) says that an MPTCP host should send
a TCP reset if the token in a MP_JOIN request is unknown.
At this time we don't do this, the 3whs completes and the 'new subflow'
is reset afterwards. There are two ways to allow MPTCP to send the
reset.
1. override 'send_synack' callback and emit the rst from there.
The drawback is that the request socket gets inserted into the
listeners queue just to get removed again right away.
2. Send the reset from the 'route_req' function instead.
This avoids the 'add&remove request socket', but route_req lacks the
skb that is required to send the TCP reset.
Instead of just adding the skb to that function for MPTCP sake alone,
Paolo suggested to merge init_req and route_req functions.
This saves one indirection from syn processing path and provides the skb
to the merged function at the same time.
'send reset on unknown mptcp join token' is added in next patch.
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
include/net/tcp.h | 9 ++++-----
net/ipv4/tcp_input.c | 9 ++-------
net/ipv4/tcp_ipv4.c | 9 +++++++--
net/ipv6/tcp_ipv6.c | 9 +++++++--
net/mptcp/subflow.c | 36 ++++++++++++++++++++++++------------
5 files changed, 44 insertions(+), 28 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index d5d22c411918..4525d6256321 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2007,15 +2007,14 @@ struct tcp_request_sock_ops {
const struct sock *sk,
const struct sk_buff *skb);
#endif
- void (*init_req)(struct request_sock *req,
- const struct sock *sk_listener,
- struct sk_buff *skb);
#ifdef CONFIG_SYN_COOKIES
__u32 (*cookie_init_seq)(const struct sk_buff *skb,
__u16 *mss);
#endif
- struct dst_entry *(*route_req)(const struct sock *sk, struct flowi *fl,
- const struct request_sock *req);
+ struct dst_entry *(*route_req)(const struct sock *sk,
+ struct sk_buff *skb,
+ struct flowi *fl,
+ struct request_sock *req);
u32 (*init_seq)(const struct sk_buff *skb);
u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb);
int (*send_synack)(const struct sock *sk, struct dst_entry *dst,
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index fb3a7750f623..9e8a6c1aa019 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6799,18 +6799,13 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
/* Note: tcp_v6_init_req() might override ir_iif for link locals */
inet_rsk(req)->ir_iif = inet_request_bound_dev_if(sk, skb);
- af_ops->init_req(req, sk, skb);
-
- if (security_inet_conn_request(sk, skb, req))
+ dst = af_ops->route_req(sk, skb, &fl, req);
+ if (!dst)
goto drop_and_free;
if (tmp_opt.tstamp_ok)
tcp_rsk(req)->ts_off = af_ops->init_ts_off(net, skb);
- dst = af_ops->route_req(sk, &fl, req);
- if (!dst)
- goto drop_and_free;
-
if (!want_cookie && !isn) {
/* Kill the following clause, if you dislike this way. */
if (!net->ipv4.sysctl_tcp_syncookies &&
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index e4b31e70bd30..af2338294598 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1444,9 +1444,15 @@ static void tcp_v4_init_req(struct request_sock *req,
}
static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
+ struct sk_buff *skb,
struct flowi *fl,
- const struct request_sock *req)
+ struct request_sock *req)
{
+ tcp_v4_init_req(req, sk, skb);
+
+ if (security_inet_conn_request(sk, skb, req))
+ return NULL;
+
return inet_csk_route_req(sk, &fl->u.ip4, req);
}
@@ -1466,7 +1472,6 @@ const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
.req_md5_lookup = tcp_v4_md5_lookup,
.calc_md5_hash = tcp_v4_md5_hash_skb,
#endif
- .init_req = tcp_v4_init_req,
#ifdef CONFIG_SYN_COOKIES
.cookie_init_seq = cookie_v4_init_sequence,
#endif
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 992cbf3eb9e3..1a1510513739 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -828,9 +828,15 @@ static void tcp_v6_init_req(struct request_sock *req,
}
static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
+ struct sk_buff *skb,
struct flowi *fl,
- const struct request_sock *req)
+ struct request_sock *req)
{
+ tcp_v6_init_req(req, sk, skb);
+
+ if (security_inet_conn_request(sk, skb, req))
+ return NULL;
+
return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
}
@@ -851,7 +857,6 @@ const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
.req_md5_lookup = tcp_v6_md5_lookup,
.calc_md5_hash = tcp_v6_md5_hash_skb,
#endif
- .init_req = tcp_v6_init_req,
#ifdef CONFIG_SYN_COOKIES
.cookie_init_seq = cookie_v6_init_sequence,
#endif
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 023c856424b7..727e607f40d2 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -228,27 +228,39 @@ int mptcp_subflow_init_cookie_req(struct request_sock *req,
}
EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req);
-static void subflow_v4_init_req(struct request_sock *req,
- const struct sock *sk_listener,
- struct sk_buff *skb)
+static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
+ struct sk_buff *skb,
+ struct flowi *fl,
+ struct request_sock *req)
{
+ struct dst_entry *dst;
+
tcp_rsk(req)->is_mptcp = 1;
- tcp_request_sock_ipv4_ops.init_req(req, sk_listener, skb);
+ dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req);
+ if (!dst)
+ return NULL;
- subflow_init_req(req, sk_listener, skb);
+ subflow_init_req(req, sk, skb);
+ return dst;
}
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-static void subflow_v6_init_req(struct request_sock *req,
- const struct sock *sk_listener,
- struct sk_buff *skb)
+static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
+ struct sk_buff *skb,
+ struct flowi *fl,
+ struct request_sock *req)
{
+ struct dst_entry *dst;
+
tcp_rsk(req)->is_mptcp = 1;
- tcp_request_sock_ipv6_ops.init_req(req, sk_listener, skb);
+ dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req);
+ if (!dst)
+ return NULL;
- subflow_init_req(req, sk_listener, skb);
+ subflow_init_req(req, sk, skb);
+ return dst;
}
#endif
@@ -1388,7 +1400,7 @@ void __init mptcp_subflow_init(void)
panic("MPTCP: failed to init subflow request sock ops\n");
subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops;
- subflow_request_sock_ipv4_ops.init_req = subflow_v4_init_req;
+ subflow_request_sock_ipv4_ops.route_req = subflow_v4_route_req;
subflow_specific = ipv4_specific;
subflow_specific.conn_request = subflow_v4_conn_request;
@@ -1397,7 +1409,7 @@ void __init mptcp_subflow_init(void)
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops;
- subflow_request_sock_ipv6_ops.init_req = subflow_v6_init_req;
+ subflow_request_sock_ipv6_ops.route_req = subflow_v6_route_req;
subflow_v6_specific = ipv6_specific;
subflow_v6_specific.conn_request = subflow_v6_conn_request;
From 3ecfbe3e820997033beb4181c95d80d5c9ac6f85 Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@strlen.de>
Date: Mon, 30 Nov 2020 16:36:31 +0100
Subject: [PATCH 3/3] mptcp: emit tcp reset when a join request fails
RFC 8684 says:
If the token is unknown or the host wants to refuse subflow establishment
(for example, due to a limit on the number of subflows it will permit),
the receiver will send back a reset (RST) signal, analogous to an unknown
port in TCP, containing an MP_TCPRST option (Section 3.6) with an
"MPTCP specific error" reason code.
mptcp-next doesn't support MP_TCPRST yet, this can be added in another
change.
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
net/mptcp/subflow.c | 47 ++++++++++++++++++++++++++++++++++-----------
1 file changed, 36 insertions(+), 11 deletions(-)
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 727e607f40d2..5f5815a1665f 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -112,9 +112,14 @@ static int __subflow_init_req(struct request_sock *req, const struct sock *sk_li
return 0;
}
-static void subflow_init_req(struct request_sock *req,
- const struct sock *sk_listener,
- struct sk_buff *skb)
+/* Init mptcp request socket.
+ *
+ * Returns an error code if a JOIN has failed and a TCP reset
+ * should be sent.
+ */
+static int subflow_init_req(struct request_sock *req,
+ const struct sock *sk_listener,
+ struct sk_buff *skb)
{
struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener);
struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
@@ -125,7 +130,7 @@ static void subflow_init_req(struct request_sock *req,
ret = __subflow_init_req(req, sk_listener);
if (ret)
- return;
+ return 0;
mptcp_get_options(skb, &mp_opt);
@@ -133,7 +138,7 @@ static void subflow_init_req(struct request_sock *req,
SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE);
if (mp_opt.mp_join)
- return;
+ return 0;
} else if (mp_opt.mp_join) {
SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNRX);
}
@@ -157,7 +162,7 @@ again:
} else {
subflow_req->mp_capable = 1;
}
- return;
+ return 0;
}
err = mptcp_token_new_request(req);
@@ -175,7 +180,11 @@ again:
subflow_req->remote_nonce = mp_opt.nonce;
subflow_req->msk = subflow_token_join_request(req, skb);
- if (unlikely(req->syncookie) && subflow_req->msk) {
+ /* Can't fall back to TCP in this case. */
+ if (!subflow_req->msk)
+ return -EPERM;
+
+ if (unlikely(req->syncookie)) {
if (mptcp_can_accept_new_subflow(subflow_req->msk))
subflow_init_req_cookie_join_save(subflow_req, skb);
}
@@ -183,6 +192,8 @@ again:
pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token,
subflow_req->remote_nonce, subflow_req->msk);
}
+
+ return 0;
}
int mptcp_subflow_init_cookie_req(struct request_sock *req,
@@ -234,6 +245,7 @@ static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
struct request_sock *req)
{
struct dst_entry *dst;
+ int err;
tcp_rsk(req)->is_mptcp = 1;
@@ -241,8 +253,14 @@ static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
if (!dst)
return NULL;
- subflow_init_req(req, sk, skb);
- return dst;
+ err = subflow_init_req(req, sk, skb);
+ if (err == 0)
+ return dst;
+
+ dst_release(dst);
+ if (!req->syncookie)
+ tcp_request_sock_ops.send_reset(sk, skb);
+ return NULL;
}
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
@@ -252,6 +270,7 @@ static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
struct request_sock *req)
{
struct dst_entry *dst;
+ int err;
tcp_rsk(req)->is_mptcp = 1;
@@ -259,8 +278,14 @@ static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
if (!dst)
return NULL;
- subflow_init_req(req, sk, skb);
- return dst;
+ err = subflow_init_req(req, sk, skb);
+ if (err == 0)
+ return dst;
+
+ dst_release(dst);
+ if (!req->syncookie)
+ tcp6_request_sock_ops.send_reset(sk, skb);
+ return NULL;
}
#endif