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Message-Id: <20210415144413.747208914@linuxfoundation.org>
Date: Thu, 15 Apr 2021 16:47:00 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, =?UTF-8?q?kiyin ?= <kiyin@...cent.com>,
Xiaoming Ni <nixiaoming@...wei.com>,
"David S. Miller" <davem@...emloft.net>
Subject: [PATCH 4.9 08/47] nfc: Avoid endless loops caused by repeated llcp_sock_connect()
From: Xiaoming Ni <nixiaoming@...wei.com>
commit 4b5db93e7f2afbdfe3b78e37879a85290187e6f1 upstream.
When sock_wait_state() returns -EINPROGRESS, "sk->sk_state" is
LLCP_CONNECTING. In this case, llcp_sock_connect() is repeatedly invoked,
nfc_llcp_sock_link() will add sk to local->connecting_sockets twice.
sk->sk_node->next will point to itself, that will make an endless loop
and hang-up the system.
To fix it, check whether sk->sk_state is LLCP_CONNECTING in
llcp_sock_connect() to avoid repeated invoking.
Fixes: b4011239a08e ("NFC: llcp: Fix non blocking sockets connections")
Reported-by: "kiyin(尹亮)" <kiyin@...cent.com>
Link: https://www.openwall.com/lists/oss-security/2020/11/01/1
Cc: <stable@...r.kernel.org> #v3.11
Signed-off-by: Xiaoming Ni <nixiaoming@...wei.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
net/nfc/llcp_sock.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/net/nfc/llcp_sock.c
+++ b/net/nfc/llcp_sock.c
@@ -685,6 +685,10 @@ static int llcp_sock_connect(struct sock
ret = -EISCONN;
goto error;
}
+ if (sk->sk_state == LLCP_CONNECTING) {
+ ret = -EINPROGRESS;
+ goto error;
+ }
dev = nfc_get_device(addr->dev_idx);
if (dev == NULL) {
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