summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorDavid S. Miller <davem@davemloft.net>2021-02-11 18:30:55 -0800
committerDavid S. Miller <davem@davemloft.net>2021-02-11 18:30:55 -0800
commit9c899aa6ac6ba1e28feac82871d44af0b0e7e05c (patch)
tree9f2d7cd1390816aa185fa6c8e42446c3fa2e117b
parent4c0d2e96ba055bd8911bb8287def4f8ebbad15b6 (diff)
parentd09d818ec2ed31bce94fdcfcc4700233e01f8498 (diff)
downloadlwn-9c899aa6ac6ba1e28feac82871d44af0b0e7e05c.tar.gz
lwn-9c899aa6ac6ba1e28feac82871d44af0b0e7e05c.zip
Merge branch 'mptcp-Miscellaneous-fixes'
Mat Martineau says: ==================== mptcp: Miscellaneous fixes Here are some MPTCP fixes for the -net tree, addressing various issues we have seen thanks to syzkaller and other testing: Patch 1 correctly propagates errors at connection time and for TCP fallback connections. Patch 2 sets the expected poll() events on SEND_SHUTDOWN. Patch 3 fixes a retranmit crash and unneeded retransmissions. Patch 4 fixes possible uninitialized data on the error path during socket creation. Patch 5 addresses a problem with MPTCP window updates. Patch 6 fixes a case where MPTCP retransmission can get stuck. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat
-rw-r--r--net/mptcp/options.c10
-rw-r--r--net/mptcp/protocol.c55
-rw-r--r--net/mptcp/protocol.h18
-rw-r--r--net/mptcp/subflow.c83
4 files changed, 107 insertions, 59 deletions
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index e0d21c0607e5..8fec3dabe109 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -498,8 +498,8 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+ u64 snd_data_fin_enable, ack_seq;
unsigned int dss_size = 0;
- u64 snd_data_fin_enable;
struct mptcp_ext *mpext;
unsigned int ack_size;
bool ret = false;
@@ -531,13 +531,14 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
return ret;
}
+ ack_seq = READ_ONCE(msk->ack_seq);
if (READ_ONCE(msk->use_64bit_ack)) {
ack_size = TCPOLEN_MPTCP_DSS_ACK64;
- opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq);
+ opts->ext_copy.data_ack = ack_seq;
opts->ext_copy.ack64 = 1;
} else {
ack_size = TCPOLEN_MPTCP_DSS_ACK32;
- opts->ext_copy.data_ack32 = (uint32_t)READ_ONCE(msk->ack_seq);
+ opts->ext_copy.data_ack32 = (uint32_t)ack_seq;
opts->ext_copy.ack64 = 0;
}
opts->ext_copy.use_ack = 1;
@@ -879,8 +880,7 @@ static void ack_update_msk(struct mptcp_sock *msk,
msk->wnd_end = new_wnd_end;
/* this assumes mptcp_incoming_options() is invoked after tcp_ack() */
- if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt)) &&
- sk_stream_memory_free(ssk))
+ if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt)))
__mptcp_check_push(sk, ssk);
if (after64(new_snd_una, old_snd_una)) {
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index f998a077c7dd..06da6ad31c87 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -364,8 +364,6 @@ static void mptcp_check_data_fin_ack(struct sock *sk)
/* Look for an acknowledged DATA_FIN */
if (mptcp_pending_data_fin_ack(sk)) {
- mptcp_stop_timer(sk);
-
WRITE_ONCE(msk->snd_data_fin_enable, 0);
switch (sk->sk_state) {
@@ -459,7 +457,18 @@ static bool mptcp_subflow_cleanup_rbuf(struct sock *ssk)
static void mptcp_cleanup_rbuf(struct mptcp_sock *msk)
{
struct sock *ack_hint = READ_ONCE(msk->ack_hint);
+ int old_space = READ_ONCE(msk->old_wspace);
struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ bool cleanup;
+
+ /* this is a simple superset of what tcp_cleanup_rbuf() implements
+ * so that we don't have to acquire the ssk socket lock most of the time
+ * to do actually nothing
+ */
+ cleanup = __mptcp_space(sk) - old_space >= max(0, old_space);
+ if (!cleanup)
+ return;
/* if the hinted ssk is still active, try to use it */
if (likely(ack_hint)) {
@@ -1573,6 +1582,9 @@ out:
mptcp_set_timeout(sk, ssk);
tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
info.size_goal);
+ if (!mptcp_timer_pending(sk))
+ mptcp_reset_timer(sk);
+
if (msk->snd_data_fin_enable &&
msk->snd_nxt + 1 == msk->write_seq)
mptcp_schedule_work(sk);
@@ -1867,7 +1879,7 @@ static void __mptcp_splice_receive_queue(struct sock *sk)
skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
}
-static bool __mptcp_move_skbs(struct mptcp_sock *msk, unsigned int rcv)
+static bool __mptcp_move_skbs(struct mptcp_sock *msk)
{
struct sock *sk = (struct sock *)msk;
unsigned int moved = 0;
@@ -1887,13 +1899,10 @@ static bool __mptcp_move_skbs(struct mptcp_sock *msk, unsigned int rcv)
slowpath = lock_sock_fast(ssk);
mptcp_data_lock(sk);
+ __mptcp_update_rmem(sk);
done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
mptcp_data_unlock(sk);
- if (moved && rcv) {
- WRITE_ONCE(msk->rmem_pending, min(rcv, moved));
- tcp_cleanup_rbuf(ssk, 1);
- WRITE_ONCE(msk->rmem_pending, 0);
- }
+ tcp_cleanup_rbuf(ssk, moved);
unlock_sock_fast(ssk, slowpath);
} while (!done);
@@ -1906,6 +1915,7 @@ static bool __mptcp_move_skbs(struct mptcp_sock *msk, unsigned int rcv)
ret |= __mptcp_ofo_queue(msk);
__mptcp_splice_receive_queue(sk);
mptcp_data_unlock(sk);
+ mptcp_cleanup_rbuf(msk);
}
if (ret)
mptcp_check_data_fin((struct sock *)msk);
@@ -1935,7 +1945,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
while (copied < len) {
- int bytes_read, old_space;
+ int bytes_read;
bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied);
if (unlikely(bytes_read < 0)) {
@@ -1946,14 +1956,11 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
copied += bytes_read;
- if (skb_queue_empty(&msk->receive_queue) &&
- __mptcp_move_skbs(msk, len - copied))
- continue;
-
/* be sure to advertise window change */
- old_space = READ_ONCE(msk->old_wspace);
- if ((tcp_space(sk) - old_space) >= old_space)
- mptcp_cleanup_rbuf(msk);
+ mptcp_cleanup_rbuf(msk);
+
+ if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))
+ continue;
/* only the master socket status is relevant here. The exit
* conditions mirror closely tcp_recvmsg()
@@ -1981,7 +1988,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
/* race breaker: the shutdown could be after the
* previous receive queue check
*/
- if (__mptcp_move_skbs(msk, len - copied))
+ if (__mptcp_move_skbs(msk))
continue;
break;
}
@@ -2014,7 +2021,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
/* .. race-breaker: ssk might have gotten new data
* after last __mptcp_move_skbs() returned false.
*/
- if (unlikely(__mptcp_move_skbs(msk, 0)))
+ if (unlikely(__mptcp_move_skbs(msk)))
set_bit(MPTCP_DATA_READY, &msk->flags);
} else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) {
/* data to read but mptcp_wait_data() cleared DATA_READY */
@@ -2299,6 +2306,7 @@ static void mptcp_worker(struct work_struct *work)
if (!test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
goto unlock;
+ __mptcp_clean_una(sk);
dfrag = mptcp_rtx_head(sk);
if (!dfrag)
goto unlock;
@@ -2959,6 +2967,8 @@ static void mptcp_release_cb(struct sock *sk)
mptcp_push_pending(sk, 0);
spin_lock_bh(&sk->sk_lock.slock);
}
+ if (test_and_clear_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags))
+ __mptcp_error_report(sk);
/* clear any wmem reservation and errors */
__mptcp_update_wmem(sk);
@@ -3319,7 +3329,7 @@ static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
struct sock *sk = (struct sock *)msk;
if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
- return 0;
+ return EPOLLOUT | EPOLLWRNORM;
if (sk_stream_is_writeable(sk))
return EPOLLOUT | EPOLLWRNORM;
@@ -3352,9 +3362,16 @@ static __poll_t mptcp_poll(struct file *file, struct socket *sock,
mask |= mptcp_check_readable(msk);
mask |= mptcp_check_writeable(msk);
}
+ if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
+ mask |= EPOLLHUP;
if (sk->sk_shutdown & RCV_SHUTDOWN)
mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
+ /* This barrier is coupled with smp_wmb() in tcp_reset() */
+ smp_rmb();
+ if (sk->sk_err)
+ mask |= EPOLLERR;
+
return mask;
}
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index d67de793d363..8d9f0ff10cb8 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -95,6 +95,7 @@
#define MPTCP_WORK_CLOSE_SUBFLOW 5
#define MPTCP_PUSH_PENDING 6
#define MPTCP_CLEAN_UNA 7
+#define MPTCP_ERROR_REPORT 8
static inline bool before64(__u64 seq1, __u64 seq2)
{
@@ -233,7 +234,6 @@ struct mptcp_sock {
u64 wnd_end;
unsigned long timer_ival;
u32 token;
- int rmem_pending;
int rmem_released;
unsigned long flags;
bool can_ack;
@@ -292,7 +292,7 @@ static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
static inline int __mptcp_space(const struct sock *sk)
{
- return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_pending);
+ return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_released);
}
static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
@@ -325,20 +325,13 @@ static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
}
-static inline struct mptcp_data_frag *mptcp_rtx_tail(const struct sock *sk)
+static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
- if (!before64(msk->snd_nxt, READ_ONCE(msk->snd_una)))
+ if (msk->snd_una == READ_ONCE(msk->snd_nxt))
return NULL;
- return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
-}
-
-static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk)
-{
- struct mptcp_sock *msk = mptcp_sk(sk);
-
return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
}
@@ -414,6 +407,7 @@ struct mptcp_subflow_context {
void (*tcp_data_ready)(struct sock *sk);
void (*tcp_state_change)(struct sock *sk);
void (*tcp_write_space)(struct sock *sk);
+ void (*tcp_error_report)(struct sock *sk);
struct rcu_head rcu;
};
@@ -478,6 +472,7 @@ static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
sk->sk_data_ready = ctx->tcp_data_ready;
sk->sk_state_change = ctx->tcp_state_change;
sk->sk_write_space = ctx->tcp_write_space;
+ sk->sk_error_report = ctx->tcp_error_report;
inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
}
@@ -505,6 +500,7 @@ bool mptcp_finish_join(struct sock *sk);
bool mptcp_schedule_work(struct sock *sk);
void __mptcp_check_push(struct sock *sk, struct sock *ssk);
void __mptcp_data_acked(struct sock *sk);
+void __mptcp_error_report(struct sock *sk);
void mptcp_subflow_eof(struct sock *sk);
bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
void __mptcp_flush_join_list(struct mptcp_sock *msk);
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 278cbe3e539e..8b2338dfdc80 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -92,7 +92,7 @@ static struct mptcp_sock *subflow_token_join_request(struct request_sock *req,
return msk;
}
-static int __subflow_init_req(struct request_sock *req, const struct sock *sk_listener)
+static void subflow_init_req(struct request_sock *req, const struct sock *sk_listener)
{
struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
@@ -100,16 +100,6 @@ static int __subflow_init_req(struct request_sock *req, const struct sock *sk_li
subflow_req->mp_join = 0;
subflow_req->msk = NULL;
mptcp_token_init_request(req);
-
-#ifdef CONFIG_TCP_MD5SIG
- /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
- * TCP option space.
- */
- if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info))
- return -EINVAL;
-#endif
-
- return 0;
}
/* Init mptcp request socket.
@@ -117,20 +107,23 @@ static int __subflow_init_req(struct request_sock *req, const struct sock *sk_li
* 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)
+static int subflow_check_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);
struct mptcp_options_received mp_opt;
- int ret;
pr_debug("subflow_req=%p, listener=%p", subflow_req, listener);
- ret = __subflow_init_req(req, sk_listener);
- if (ret)
- return 0;
+#ifdef CONFIG_TCP_MD5SIG
+ /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
+ * TCP option space.
+ */
+ if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info))
+ return -EINVAL;
+#endif
mptcp_get_options(skb, &mp_opt);
@@ -205,10 +198,7 @@ int mptcp_subflow_init_cookie_req(struct request_sock *req,
struct mptcp_options_received mp_opt;
int err;
- err = __subflow_init_req(req, sk_listener);
- if (err)
- return err;
-
+ subflow_init_req(req, sk_listener);
mptcp_get_options(skb, &mp_opt);
if (mp_opt.mp_capable && mp_opt.mp_join)
@@ -248,12 +238,13 @@ static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
int err;
tcp_rsk(req)->is_mptcp = 1;
+ subflow_init_req(req, sk);
dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req);
if (!dst)
return NULL;
- err = subflow_init_req(req, sk, skb);
+ err = subflow_check_req(req, sk, skb);
if (err == 0)
return dst;
@@ -273,12 +264,13 @@ static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
int err;
tcp_rsk(req)->is_mptcp = 1;
+ subflow_init_req(req, sk);
dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req);
if (!dst)
return NULL;
- err = subflow_init_req(req, sk, skb);
+ err = subflow_check_req(req, sk, skb);
if (err == 0)
return dst;
@@ -1043,6 +1035,46 @@ static void subflow_write_space(struct sock *ssk)
/* we take action in __mptcp_clean_una() */
}
+void __mptcp_error_report(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ int err = sock_error(ssk);
+
+ if (!err)
+ continue;
+
+ /* only propagate errors on fallen-back sockets or
+ * on MPC connect
+ */
+ if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk))
+ continue;
+
+ inet_sk_state_store(sk, inet_sk_state_load(ssk));
+ sk->sk_err = -err;
+
+ /* This barrier is coupled with smp_rmb() in mptcp_poll() */
+ smp_wmb();
+ sk->sk_error_report(sk);
+ break;
+ }
+}
+
+static void subflow_error_report(struct sock *ssk)
+{
+ struct sock *sk = mptcp_subflow_ctx(ssk)->conn;
+
+ mptcp_data_lock(sk);
+ if (!sock_owned_by_user(sk))
+ __mptcp_error_report(sk);
+ else
+ set_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags);
+ mptcp_data_unlock(sk);
+}
+
static struct inet_connection_sock_af_ops *
subflow_default_af_ops(struct sock *sk)
{
@@ -1352,9 +1384,11 @@ static int subflow_ulp_init(struct sock *sk)
ctx->tcp_data_ready = sk->sk_data_ready;
ctx->tcp_state_change = sk->sk_state_change;
ctx->tcp_write_space = sk->sk_write_space;
+ ctx->tcp_error_report = sk->sk_error_report;
sk->sk_data_ready = subflow_data_ready;
sk->sk_write_space = subflow_write_space;
sk->sk_state_change = subflow_state_change;
+ sk->sk_error_report = subflow_error_report;
out:
return err;
}
@@ -1407,6 +1441,7 @@ static void subflow_ulp_clone(const struct request_sock *req,
new_ctx->tcp_data_ready = old_ctx->tcp_data_ready;
new_ctx->tcp_state_change = old_ctx->tcp_state_change;
new_ctx->tcp_write_space = old_ctx->tcp_write_space;
+ new_ctx->tcp_error_report = old_ctx->tcp_error_report;
new_ctx->rel_write_seq = 1;
new_ctx->tcp_sock = newsk;