netdev - [PATCH AUTOSEL 4.9 17/36] net: call sk_dst_reset when set SO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20190108193348.123880-17-sashal@kernel.org>
Date:   Tue,  8 Jan 2019 14:33:29 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     yupeng <yupeng0921@...il.com>,
        "David S . Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>, netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 4.9 17/36] net: call sk_dst_reset when set SO_DONTROUTE

From: yupeng <yupeng0921@...il.com>

[ Upstream commit 0fbe82e628c817e292ff588cd5847fc935e025f2 ]

after set SO_DONTROUTE to 1, the IP layer should not route packets if
the dest IP address is not in link scope. But if the socket has cached
the dst_entry, such packets would be routed until the sk_dst_cache
expires. So we should clean the sk_dst_cache when a user set
SO_DONTROUTE option. Below are server/client python scripts which
could reprodue this issue:

server side code:

==========================================================================
import socket
import struct
import time

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('0.0.0.0', 9000))
s.listen(1)
sock, addr = s.accept()
sock.setsockopt(socket.SOL_SOCKET, socket.SO_DONTROUTE, struct.pack('i', 1))
while True:
    sock.send(b'foo')
    time.sleep(1)
==========================================================================

client side code:
==========================================================================
import socket
import time

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('server_address', 9000))
while True:
    data = s.recv(1024)
    print(data)
==========================================================================

Signed-off-by: yupeng <yupeng0921@...il.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/core/sock.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/core/sock.c b/net/core/sock.c
index 1c4c43483b54..8566da877ec2 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -699,6 +699,7 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
 		break;
 	case SO_DONTROUTE:
 		sock_valbool_flag(sk, SOCK_LOCALROUTE, valbool);
+		sk_dst_reset(sk);
 		break;
 	case SO_BROADCAST:
 		sock_valbool_flag(sk, SOCK_BROADCAST, valbool);
-- 
2.19.1