From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794590037; b=ijnB3CvpLl5apO8tj8RDXkwxxBdIikRYYEBY0ePQXa9u6B/1XTfDZJNdHzPmF5DSKHuZ 3HhXuKDTrqhcnsuXcvUKxxPlA4ngmx3jwtlY8MmUjB7/Jow2Tvu+101vwOiwpmfOmglCJ r27IyW1OGhB2NQT9kpJf2TF3Dx7Y+PaXbIwETxgOHtb2ezloOPHpmkbOAeyhJiZI4rM42 G2y0p5G0aaI+CH9mJPWpX3hlxptoZt2qfPuv7Gvi7lE5YYclfaw9JgvWuUDglPWsKp7FU TyxMR/XVogYI4xTGC0vD6iVv5esnts7N5elZlaNc/Hcan3VUTe2JuaouL/ZjbFOw/Ag== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590037; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=FPZPiM8QH0BFMbq1HP3A2wAZZcsYUxor6LPxWAbA/Po=; b=fQk9uAj9bX72GCYySDGc6UvtDwijH/1MyyvGFw4htWS8EToAmoD/oLXlNxc49kHGT+8d zaUp7/ZdkKo9hJR435ktBLCfSfsiTrAWA8XhbkS/07r9TP0QfVh9E9Ya61ZMOslH3PfS8 bp9YblfAfVk5wrbjMmlTzfhIAfxNQtLO2HJQY8fBstGICpLr46uDC3gL9u+RMzjw9ps0j VB9sMJwSf1RA4ko4CXuk+HxLvvRPPQLF/I3NKWiuiyuQm3Nldk4ZcApBxBAmPnjUss2js RZ+8qnSQ5RIGZrbUJTtpjrwhFgkFZ2+HWmjdnEKCNopkqyaldK/XwFVCg1Lx0sFjLpA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=v4v4gADK; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 67276606A8BC; Fri, 13 Nov 2026 17:13:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=v4v4gADK Received: by smtp.kernel.org (Postfix) with ESMTPSA id 132831F000C5; Fri, 13 Nov 2026 17:13:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590037; bh=FPZPiM8QH0BFMbq1HP3A2wAZZcsYUxor6LPxWAbA/Po=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=v4v4gADKjpGHlOzytpegvqM3wb6xarzYejhT4LKcNCUg9sTrV/4ci0Q0yNKbqR6+8 CbJIuB3nAMiyqx0xBeRT6a4hAX0vcpqwXZTUr+vjGH00MMxgek/+WC3g4dupYR7Wmd U1iLZ1zBBQhxah+lEE7x7uIwiJYcIS3dhwlksw5s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+d5c77cabf7a3492aa650@syzkaller.appspotmail.com, Chuck Lever , Sasha Levin Subject: [PATCH 6.18 047/686] NFSD: Move the cld upcall message out of the callers stack frame Date: Fri, 13 Nov 2026 10:43:00 -0500 Message-ID: <20261113153822.555574261@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153820.902362109@linuxfoundation.org> References: <20261113153820.902362109@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chuck Lever [ Upstream commit c559b05610557fa3c6c30259261f6dae523b3f23 ] __cld_pipe_upcall() builds its struct rpc_pipe_msg on the stack and hands it to rpc_queue_upcall(), which links it into a list the pipe owns until the message is released. Only the completion rules keep that frame alive for as long as the pipe refers to it, and the peer that drives those rules is an untrusted userspace daemon. The gss and idmap upcalls do not take that on: each keeps the message in the object it already allocates. Do the same here and put the message in struct cld_upcall, beside the reply buffer it carries. cld_pipe_destroy_msg() then reaches the upcall from the message directly rather than through msg->data. Reported-by: syzbot+d5c77cabf7a3492aa650@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d5c77cabf7a3492aa650 Link: https://patch.msgid.link/20260901-alemi-v2-2-e163f94a3a6e@kernel.org Signed-off-by: Chuck Lever Stable-dep-of: 2a83fcb50f3c ("NFSD: Complete a cld upcall when the daemon closes the pipe") Signed-off-by: Sasha Levin --- fs/nfsd/nfs4recover.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index d04a7d3aabbc8..b001d3277b9f9 100644 --- a/fs/nfsd/nfs4recover.c +++ b/fs/nfsd/nfs4recover.c @@ -711,6 +711,7 @@ struct cld_upcall { struct completion cu_done; /* daemon has read the whole upcall; protected by cn_lock */ bool cu_inflight; + struct rpc_pipe_msg cu_pipe_msg; union { struct cld_msg_hdr cu_hdr; struct cld_msg cu_msg; @@ -722,22 +723,22 @@ static int __cld_pipe_upcall(struct rpc_pipe *pipe, void *cmsg, struct nfsd_net *nn) { int ret; - struct rpc_pipe_msg msg; struct cld_upcall *cup = container_of(cmsg, struct cld_upcall, cu_u); + struct rpc_pipe_msg *msg = &cup->cu_pipe_msg; - memset(&msg, 0, sizeof(msg)); - msg.data = cmsg; - msg.len = nn->client_tracking_ops->msglen; + memset(msg, 0, sizeof(*msg)); + msg->data = cmsg; + msg->len = nn->client_tracking_ops->msglen; - ret = rpc_queue_upcall(pipe, &msg); + ret = rpc_queue_upcall(pipe, msg); if (ret < 0) { goto out; } wait_for_completion(&cup->cu_done); - if (msg.errno < 0) - ret = msg.errno; + if (msg->errno < 0) + ret = msg->errno; out: return ret; } @@ -910,9 +911,8 @@ cld_pipe_downcall(struct file *filp, const char __user *src, size_t mlen) static void cld_pipe_destroy_msg(struct rpc_pipe_msg *msg) { - struct cld_msg *cmsg = msg->data; - struct cld_upcall *cup = container_of(cmsg, struct cld_upcall, - cu_u.cu_msg); + struct cld_upcall *cup = container_of(msg, struct cld_upcall, + cu_pipe_msg); struct cld_net *cn = cup->cu_net; /* -- 2.53.0