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 9BF1233E36A; Wed, 3 Dec 2025 16:38:24 +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=1764779904; cv=none; b=Ugi7ofy6AfTA2qpcBqdLtUBg9+PvunKPmma2ef5XPNqDGepbvdQijEZlGsfGViqluAzMbiWND1Z8OjDaoUGoLH9xnIm8OR3GzWIW4utSpbuKqFcgDHq0dMtTkBo9sAsNzWvQGROzI0V26Rcy3f/HgPHsPryIAdvqGAeSYJsmK38= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764779904; c=relaxed/simple; bh=YuutO9no87joUamNLX3hgFkeV71TaZwIprJU1T1TdaQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MVStltO83YaGoqrQdITIWDLj/5oQ8cpsH3ua8XY6V9SY1tp3yH/9cAMNQrf3D1psyYvoUXOFubZSy8nGDqXsie9QwZ269jAgeUK8FyEUdy8Qr8PT+ZVfzi0G27SX4sq/3zqbqScPzECYK1MdIdgyBX6IWggEqF7OoPwlIyv4eYg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=OATzdd43; 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="OATzdd43" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 04DDCC4CEF5; Wed, 3 Dec 2025 16:38:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1764779904; bh=YuutO9no87joUamNLX3hgFkeV71TaZwIprJU1T1TdaQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OATzdd431RiwuwvaZD0kkAhYl8bBVTf0qRmVsYU70pGnQIJ+L3qZE5C1zCFWLmF0D cSIGrT+Td9ofpQGsyeYF2jXk78W+LtiruPkxaCkrXcSvmQp2IcBEDoWNWEugNgf3yU GQXLFR9iS+slsFqRI2lFjOWl50Pkg7EBdYZoXFMI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Joshua Rogers , Namjae Jeon , Steve French Subject: [PATCH 6.1 398/568] ksmbd: close accepted socket when per-IP limit rejects connection Date: Wed, 3 Dec 2025 16:26:40 +0100 Message-ID: <20251203152455.268985788@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251203152440.645416925@linuxfoundation.org> References: <20251203152440.645416925@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-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Joshua Rogers commit 98a5fd31cbf72d46bf18e50b3ab0ce86d5f319a9 upstream. When the per-IP connection limit is exceeded in ksmbd_kthread_fn(), the code sets ret = -EAGAIN and continues the accept loop without closing the just-accepted socket. That leaks one socket per rejected attempt from a single IP and enables a trivial remote DoS. Release client_sk before continuing. This bug was found with ZeroPath. Cc: stable@vger.kernel.org Signed-off-by: Joshua Rogers Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/smb/server/transport_tcp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/fs/smb/server/transport_tcp.c +++ b/fs/smb/server/transport_tcp.c @@ -282,8 +282,11 @@ static int ksmbd_kthread_fn(void *p) } } up_read(&conn_list_lock); - if (ret == -EAGAIN) + if (ret == -EAGAIN) { + /* Per-IP limit hit: release the just-accepted socket. */ + sock_release(client_sk); continue; + } skip_max_ip_conns_limit: if (server_conf.max_connections &&