This implements SOCK_DESTROY for TCP sockets. It causes all
blocking calls on the socket to fail fast with ECONNABORTED and
causes a protocol close of the socket. It informs the other end
of the connection by sending a RST, i.e., initiating a TCP ABORT
as per RFC 793. ECONNABORTED was chosen for consistency with
FreeBSD.
Signed-off-by: Lorenzo Colitti <lore...@google.com>
---
net/ipv4/Kconfig | 13 +++++++++++++
net/ipv4/tcp_diag.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
net/ipv4/tcp_output.c | 1 +
3 files changed, 60 insertions(+)
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 416dfa0..31c4496 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -436,6 +436,19 @@ config INET_UDP_DIAG
Support for UDP socket monitoring interface used by the ss tool.
If unsure, say Y.
+config INET_DIAG_DESTROY
+ bool "INET: allow privileged process to administratively close sockets"
+ depends on INET_DIAG && (IPV6 || IPV6=n)
+ default n
+ ---help---
+ Provides a SOCK_DESTROY operation that allows privileged processes
+ (e.g., a connection manager or a network administration tool such as
+ ss) to close sockets opened by other processes. Closing a socket in
+ this way interrupts any blocking read/writes/connect operations on
+ the socket and causes future socket calls to behave as if the socket
+ had been disconnected.
+ If unsure, say N.
+
menuconfig TCP_CONG_ADVANCED
bool "TCP: advanced congestion control"
---help---
diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
index b316040..31d3e0c 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -10,6 +10,7 @@
*/
#include <linux/module.h>
+#include <linux/net.h>
#include <linux/inet_diag.h>
#include <linux/tcp.h>
@@ -46,12 +47,57 @@ static int tcp_diag_dump_one(struct sk_buff *in_skb, const
struct nlmsghdr *nlh,
return inet_diag_dump_one_icsk(&tcp_hashinfo, in_skb, nlh, req);
}
+#if IS_ENABLED(CONFIG_INET_DIAG_DESTROY)
+static int tcp_diag_destroy(struct sk_buff *in_skb,
+ const struct inet_diag_req_v2 *req)
+{
+ struct sock *sk;
+ struct net *net = sock_net(in_skb->sk);
+
+ if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
+ return -EPERM;
+
+ sk = inet_diag_find_one_icsk(net, &tcp_hashinfo, req);
+ if (IS_ERR(sk))
+ return PTR_ERR(sk);
+
+ if (!sk_fullsock(sk)) {
+ sock_gen_put(sk);
+ return -EOPNOTSUPP;
+ }
+
+ /* Don't race with userspace socket closes such as tcp_close. */
+ lock_sock(sk);
+
+ /* Don't race with BH socket closes such as inet_csk_listen_stop. */
+ local_bh_disable();
+ bh_lock_sock(sk);
+
+ if (!sock_flag(sk, SOCK_DEAD)) {
+ smp_wmb(); /* Be consistent with tcp_reset */
+ sk->sk_err = ECONNABORTED;
+ sk->sk_error_report(sk);
+ tcp_send_active_reset(sk, GFP_ATOMIC);
+ tcp_done(sk);
+ }
+
+ bh_unlock_sock(sk);
+ local_bh_enable();
+ release_sock(sk);
+ sock_put(sk);
+ return 0;
+}
+#endif
+
static const struct inet_diag_handler tcp_diag_handler = {
.dump = tcp_diag_dump,
.dump_one = tcp_diag_dump_one,
.idiag_get_info = tcp_diag_get_info,
.idiag_type = IPPROTO_TCP,
.idiag_info_size = sizeof(struct tcp_info),
+#if IS_ENABLED(CONFIG_INET_DIAG_DESTROY)
+ .destroy = tcp_diag_destroy,
+#endif
};
static int __init tcp_diag_init(void)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index cb7ca56..754a537 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2894,6 +2894,7 @@ void tcp_send_active_reset(struct sock *sk, gfp_t
priority)
TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTRSTS);
}
+EXPORT_SYMBOL_GPL(tcp_send_active_reset);
/* Send a crossed SYN-ACK during socket establishment.
* WARNING: This routine must only be called when we have already sent
--
2.6.0.rc2.230.g3dd15c0
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