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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
        syzbot <syzkaller@googlegroups.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 44/86] ipv4: raw: lock the socket in raw_bind()
Date:   Mon,  7 Feb 2022 12:06:07 +0100
Message-Id: <20220207103758.989908777@linuxfoundation.org>
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From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 153a0d187e767c68733b8e9f46218eb1f41ab902 ]

For some reason, raw_bind() forgot to lock the socket.

BUG: KCSAN: data-race in __ip4_datagram_connect / raw_bind

write to 0xffff8881170d4308 of 4 bytes by task 5466 on cpu 0:
 raw_bind+0x1b0/0x250 net/ipv4/raw.c:739
 inet_bind+0x56/0xa0 net/ipv4/af_inet.c:443
 __sys_bind+0x14b/0x1b0 net/socket.c:1697
 __do_sys_bind net/socket.c:1708 [inline]
 __se_sys_bind net/socket.c:1706 [inline]
 __x64_sys_bind+0x3d/0x50 net/socket.c:1706
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881170d4308 of 4 bytes by task 5468 on cpu 1:
 __ip4_datagram_connect+0xb7/0x7b0 net/ipv4/datagram.c:39
 ip4_datagram_connect+0x2a/0x40 net/ipv4/datagram.c:89
 inet_dgram_connect+0x107/0x190 net/ipv4/af_inet.c:576
 __sys_connect_file net/socket.c:1900 [inline]
 __sys_connect+0x197/0x1b0 net/socket.c:1917
 __do_sys_connect net/socket.c:1927 [inline]
 __se_sys_connect net/socket.c:1924 [inline]
 __x64_sys_connect+0x3d/0x50 net/socket.c:1924
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000 -> 0x0003007f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5468 Comm: syz-executor.5 Not tainted 5.17.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ipv4/raw.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 21800979ed621..8cae691c3c9f4 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -725,6 +725,7 @@ static int raw_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 	int ret = -EINVAL;
 	int chk_addr_ret;
 
+	lock_sock(sk);
 	if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_in))
 		goto out;
 
@@ -744,7 +745,9 @@ static int raw_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 		inet->inet_saddr = 0;  /* Use device */
 	sk_dst_reset(sk);
 	ret = 0;
-out:	return ret;
+out:
+	release_sock(sk);
+	return ret;
 }
 
 /*
-- 
2.34.1