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 B122C29D27A; Mon, 13 Apr 2026 16:28:58 +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=1776097738; cv=none; b=tsIjTHGi3e8b4n+jlNlqGjQwR34Vpys885mWrSmAyPuO7u9oxZk6oXEFKlQp5OPy4EO//HbBM2iFWw4WZjTHBVuVd2EBJMdgkLvLdI1aOPW1WpDIQ6OICDXkr5mHTokoM0qWtzvOWzACGg41NasNOpSaY9Y1Q8NiudH4rWyhB3A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776097738; c=relaxed/simple; bh=AIb3bK47fgl0ePukb+sMUXobAEeD6BfJB89u+nAnHQw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hAYbDajwrn33wuFw665SHTOTEf6gVB9hUqdlLkYvn2vfWoaZ7Uc8nNiectdvPJ54MEMoTawSTBLnoZQv+vrTGQkKA5cnvVAzvCJRrWYj7P2nxmDvOaj/EYJI7kuBGEHAzkQ1SPksbQm6ZsuISk4+SA8Jeb4pSyNQoIEqUj5DprE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=04wOMS3x; 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="04wOMS3x" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 478EFC2BCAF; Mon, 13 Apr 2026 16:28:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776097738; bh=AIb3bK47fgl0ePukb+sMUXobAEeD6BfJB89u+nAnHQw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=04wOMS3xdisDV0pr0YmcPEmM9X7DExVf7B6GIcimj4QlGeWXaLc/2+5mEkyMuK0td E/qvaqCIki551UuVeTy8zNB/RnO87iOHk4yFjIWN1u2u0LbwBAsLbDsh4E/giO9L5U ZREbkervSXh8zbJEj0P7qaT4qFL2f+cBGqDhijHU= 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 5.15 253/570] net/rose: fix NULL pointer dereference in rose_transmit_link on reconnect Date: Mon, 13 Apr 2026 17:56:24 +0200 Message-ID: <20260413155839.943405726@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260413155830.386096114@linuxfoundation.org> References: <20260413155830.386096114@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 5.15-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 04173c85d92b5..0130c13f73552 100644 --- a/net/rose/af_rose.c +++ b/net/rose/af_rose.c @@ -808,6 +808,11 @@ static int rose_connect(struct socket *sock, struct sockaddr *uaddr, int addr_le 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