bartoszek/zephyr
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

net: sockets: tcp: Fix possible race between connect/recv

Browse Source 
Installing recv callback with net_context_recv() after
net_context_connect() left an opening for a possible race - in case the
server send some data immediately after establishing TCP connection, and
Zephyr did not manage to install the callback on time, the data would be
lost, corrupting the stream.

This can be avoided, by installing the recv callback before the
connection is triggered. As net_context_recv() called w/o timeout only
registers the callback function, it should have no negative impact. The
only change on the TCP side is when the connection is closed - in case
TCP is in connect stage, do not call the recv callback (before this
change it'd be NULL at that point).

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
This commit is contained in:
Robert Lubos 2023-05-24 12:53:52 +02:00 committed by Anas Nashif
parent 5f68ea686d
commit 2c75070360
2 changed files with 11 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
subsys/net/ip/tcp.c
View File

@ -497,9 +497,7 @@ static int tcp_conn_close(struct tcp *conn, int status)
/* Make sure the connect_cb is only called once. */
conn->connect_cb = NULL;
}
}
if (conn->context->recv_cb) {
} else if (conn->context->recv_cb) {
conn->context->recv_cb(conn->context, NULL, NULL, NULL,
status, conn->recv_user_data);
}

21
subsys/net/lib/sockets/sockets.c
View File

@ -490,15 +490,12 @@ static void zsock_connected_cb(struct net_context *ctx, int status, void *user_d
if (status < 0) {
ctx->user_data = INT_TO_POINTER(-status);
sock_set_error(ctx);
} else if (status == 0) {
(void)net_context_recv(ctx, zsock_received_cb, K_NO_WAIT, ctx->user_data);
}
}
int zsock_connect_ctx(struct net_context *ctx, const struct sockaddr *addr,
socklen_t addrlen)
{
k_timeout_t timeout;
#if defined(CONFIG_SOCKS)
if (net_context_is_proxy_enabled(ctx)) {
@ -516,17 +513,19 @@ int zsock_connect_ctx(struct net_context *ctx, const struct sockaddr *addr,
} else {
SET_ERRNO(-EALREADY);
}
} else if (sock_is_nonblock(ctx)) {
timeout = K_NO_WAIT;
SET_ERRNO(net_context_connect(ctx, addr, addrlen,
zsock_connected_cb, timeout,
ctx->user_data));
} else {
timeout = K_MSEC(CONFIG_NET_SOCKETS_CONNECT_TIMEOUT);
SET_ERRNO(net_context_connect(ctx, addr, addrlen, NULL,
timeout, NULL));
k_timeout_t timeout = K_MSEC(CONFIG_NET_SOCKETS_CONNECT_TIMEOUT);
net_context_connect_cb_t cb = NULL;
if (sock_is_nonblock(ctx)) {
timeout = K_NO_WAIT;
cb = zsock_connected_cb;
}
SET_ERRNO(net_context_recv(ctx, zsock_received_cb, K_NO_WAIT,
ctx->user_data));
SET_ERRNO(net_context_connect(ctx, addr, addrlen, cb, timeout,
ctx->user_data));
}
return 0;