From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A2E973AD538; Mon, 23 Mar 2026 13:55:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774274158; cv=none; b=VJoPP6fDwPUFT96omW8bU1lryHG6DH2IvRnzhjvPbOjhBm5NHpmtEEWW5MZf/2H+tvTvq7TxPKqrId+EKswkbMhYBTNLpv0IM1GbTtiYlzXvVEbatZHYJaqbRFdEOPY/UnXniKz/F/+fSm+doulrIPwxLOBJQXL2v7x1IX81nBQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774274158; c=relaxed/simple; bh=C95JoYdPGjnVZnXTm6kT/rmuAcJkGUM5qG+9A19YVBw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FX0sb6DriroZqcotd3iJK2iaTKkAz7Z4Bytc1MOqexLamps3Yi+GCpPo4gF+qgX0cO7QVVrLL5X4Od0KRFA1MslIKrW8Ca9PcKA9oZxNeFm5GiWsArl06dyiPiDoxaBYF7RL86DLgXYh5Go7r51s/lCG3MlNEdqpSOwWNgTsCSk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qpnYZyMU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qpnYZyMU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1BF8EC4CEF7; Mon, 23 Mar 2026 13:55:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774274158; bh=C95JoYdPGjnVZnXTm6kT/rmuAcJkGUM5qG+9A19YVBw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qpnYZyMUIj6byl+L3cRKw5zUrtDKw/TB16Kp/7qkmzPxBNQgab4Movo6BJooYjoHC JUZqjntlmZxSaPA4Aq1UHtyL4QH6lbUfqwVDhB3ksUl0VgEr0Fs61u+EypKG6IAJje 2F1nhQEVN1Mg9kfmIuj9BYebKD6XFQBUut6habv8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+d00f90e0af54102fb271@syzkaller.appspotmail.com, Eric Dumazet , Jiayuan Chen , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.19 129/220] net/rose: fix NULL pointer dereference in rose_transmit_link on reconnect Date: Mon, 23 Mar 2026 14:45:06 +0100 Message-ID: <20260323134508.662891355@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134504.575022936@linuxfoundation.org> References: <20260323134504.575022936@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiayuan Chen [ Upstream commit e1f0a18c9564cdb16523c802e2c6fe5874e3d944 ] syzkaller reported a bug [1], and the reproducer is available at [2]. ROSE sockets use four sk->sk_state values: TCP_CLOSE, TCP_LISTEN, TCP_SYN_SENT, and TCP_ESTABLISHED. rose_connect() already rejects calls for TCP_ESTABLISHED (-EISCONN) and TCP_CLOSE with SS_CONNECTING (-ECONNREFUSED), but lacks a check for TCP_SYN_SENT. When rose_connect() is called a second time while the first connection attempt is still in progress (TCP_SYN_SENT), it overwrites rose->neighbour via rose_get_neigh(). If that returns NULL, the socket is left with rose->state == ROSE_STATE_1 but rose->neighbour == NULL. When the socket is subsequently closed, rose_release() sees ROSE_STATE_1 and calls rose_write_internal() -> rose_transmit_link(skb, NULL), causing a NULL pointer dereference. Per connect(2), a second connect() while a connection is already in progress should return -EALREADY. Add this missing check for TCP_SYN_SENT to complete the state validation in rose_connect(). [1] https://syzkaller.appspot.com/bug?extid=d00f90e0af54102fb271 [2] https://gist.github.com/mrpre/9e6779e0d13e2c66779b1653fef80516 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+d00f90e0af54102fb271@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69694d6f.050a0220.58bed.0027.GAE@google.com/T/ Suggested-by: Eric Dumazet Signed-off-by: Jiayuan Chen Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260311070611.76913-1-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/rose/af_rose.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c index c0f5a515a8ce5..de18af4e40660 100644 --- a/net/rose/af_rose.c +++ b/net/rose/af_rose.c @@ -811,6 +811,11 @@ static int rose_connect(struct socket *sock, struct sockaddr_unsized *uaddr, int goto out_release; } + if (sk->sk_state == TCP_SYN_SENT) { + err = -EALREADY; + goto out_release; + } + sk->sk_state = TCP_CLOSE; sock->state = SS_UNCONNECTED; -- 2.51.0