From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 102153D8916; Tue, 13 Oct 2026 12:10:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791893431; cv=none; b=EfpJ8NDbWYXyVB6iWXWos7GgTA5Jor0Khjx9HKQ1rpI03vs8NiC89HxcXzZCUtHjWt+doOpaecCh2e+mwAltZqN5Q2djVEIfmMHggVotM1pmnvnH40wbOSEcBrJS/sAeKt2srYN0tcNAFc9a44iAnyzxo+u4w//zGSLh+ncAEaY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791893431; c=relaxed/simple; bh=ul7japmomYbmDLLqGjI6zRWSBY8ogjQu6GxG5e+sIC4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=EAVNB4vOjcVd83nlohtNO/7BGz3IUPHdLJv3rXUa3heWqbFM6pWIHKUvBOrQbGJCfQdqfW5l/KH+EWOxoljrncechLM8IZzsy0tsUu9r9j0aMIeoKiD4/yYEBw2KAD7S0TdIdN24razsW1y9gK37vFaySFzEUhj/2JVaqCMrWS4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=A7kt/Xth; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="A7kt/Xth" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68E831F000FF; Tue, 13 Oct 2026 12:10:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791893430; bh=umN1ogk2f++mLjp9t+Z776YgFC/yW06fkcqsfkWaDLA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=A7kt/XthS92ab5+dvdt/w4sQ1rjoqbSEv4UnST/Bc8nmx3e9HpKxLVbFX9i9XrTig 7Wfjz18q1cc2RdRqJ5wj7nnPYmLNWkxhYFWwK8SZqjzeYuJVTEMnbPaE0Akbx+nM43 q0v54mEatFrTBC+bPzneNXyu7qh3t7/dvplaGm10= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+706f5eb79044e686c794@syzkaller.appspotmail.com, Remi Denis-Courmont , Morduan Zang , zhanjun , =?UTF-8?q?R=C3=A9mi=20Denis-Courmont?= , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 223/621] net: phonet: do not BUG_ON() in pn_socket_autobind() on failed bind Date: Tue, 13 Oct 2026 13:33:38 +0200 Message-ID: <20261013112926.150712124@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261013112920.855194808@linuxfoundation.org> References: <20261013112920.855194808@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Morduan Zang [ Upstream commit 5b0c911bcdbd982f7748d11c0b39ec5808eae2de ] syzbot reported a kernel BUG triggered from pn_socket_sendmsg() via pn_socket_autobind(): kernel BUG at net/phonet/socket.c:213! RIP: 0010:pn_socket_autobind net/phonet/socket.c:213 [inline] RIP: 0010:pn_socket_sendmsg+0x240/0x250 net/phonet/socket.c:421 Call Trace: sock_sendmsg_nosec+0x112/0x150 net/socket.c:797 __sock_sendmsg net/socket.c:812 [inline] __sys_sendto+0x402/0x590 net/socket.c:2280 ... pn_socket_autobind() calls pn_socket_bind() with port 0 and, on -EINVAL, assumes the socket was already bound and asserts that the port is non-zero: err = pn_socket_bind(sock, ..., sizeof(struct sockaddr_pn)); if (err != -EINVAL) return err; BUG_ON(!pn_port(pn_sk(sock->sk)->sobject)); return 0; /* socket was already bound */ However pn_socket_bind() also returns -EINVAL when sk->sk_state is not TCP_CLOSE, even when the socket has never been bound and pn_port() is still 0. In that case the BUG_ON() fires and panics the kernel from a user-triggerable path. Treat the "bind returned -EINVAL but pn_port() is still 0" case as a regular error and propagate -EINVAL to the caller instead of crashing. Existing callers already translate a non-zero return from pn_socket_autobind() into -ENOBUFS/-EAGAIN, so returning -EINVAL here only changes behaviour from panic to a normal errno. Fixes: ba113a94b750 ("Phonet: common socket glue") Reported-by: syzbot+706f5eb79044e686c794@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=706f5eb79044e686c794 Suggested-by: Remi Denis-Courmont Signed-off-by: Morduan Zang Signed-off-by: zhanjun Acked-by: Rémi Denis-Courmont Link: https://patch.msgid.link/87A8960A2045AF3C+20260423010557.138124-1-zhangdandan@uniontech.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/phonet/socket.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/phonet/socket.c b/net/phonet/socket.c index db2d552e9b32e..f0e2a8bf8fdc7 100644 --- a/net/phonet/socket.c +++ b/net/phonet/socket.c @@ -208,9 +208,15 @@ static int pn_socket_autobind(struct socket *sock) sa.spn_family = AF_PHONET; err = pn_socket_bind(sock, (struct sockaddr *)&sa, sizeof(struct sockaddr_pn)); - if (err != -EINVAL) + /* + * pn_socket_bind() also returns -EINVAL when sk_state != TCP_CLOSE + * without a prior bind, so -EINVAL alone is not sufficient to infer + * that the socket was already bound. Only treat it as "already + * bound" when the port is non-zero; otherwise propagate the error + * instead of crashing the kernel. + */ + if (err != -EINVAL || unlikely(!pn_port(pn_sk(sock->sk)->sobject))) return err; - BUG_ON(!pn_port(pn_sk(sock->sk)->sobject)); return 0; /* socket was already bound */ } -- 2.53.0