This is a note to let you know that I've just added the patch titled nfc: Avoid endless loops caused by repeated llcp_sock_connect() to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nfc-avoid-endless-loops-caused-by-repeated-llcp_sock_connect.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 4b5db93e7f2afbdfe3b78e37879a85290187e6f1 Mon Sep 17 00:00:00 2001 From: Xiaoming Ni <nixiaoming@xxxxxxxxxx> Date: Thu, 25 Mar 2021 11:51:13 +0800 Subject: nfc: Avoid endless loops caused by repeated llcp_sock_connect() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Xiaoming Ni <nixiaoming@xxxxxxxxxx> 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@xxxxxxxxxxx> Link: https://www.openwall.com/lists/oss-security/2020/11/01/1 Cc: <stable@xxxxxxxxxxxxxxx> #v3.11 Signed-off-by: Xiaoming Ni <nixiaoming@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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) { Patches currently in stable-queue which might be from nixiaoming@xxxxxxxxxx are queue-4.9/nfc-avoid-endless-loops-caused-by-repeated-llcp_sock_connect.patch queue-4.9/nfc-fix-memory-leak-in-llcp_sock_connect.patch queue-4.9/nfc-fix-refcount-leak-in-llcp_sock_bind.patch queue-4.9/nfc-fix-refcount-leak-in-llcp_sock_connect.patch