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=1794590674; b=j/VcN0z4abDGd56iRjpIABIcqHEnv3HGQgmp58dxp8xyRyZNm+Iz7k2oACvBUf/9neAC 7tXZEBDK8lQMDwgeDJYG8fcZX4u/mxx8zUuKidtxft82LfMoW8cqPpi9kAQYxl8QAtvGU B3XRLCFkPLa1oeqsudSF4sut8s7fvJhFgDeFHLhmkg27xgWNYJ9V+PAkzw1duCim8nZIR I1y/FzT2IcGjD0EczQhJAXOZ2pUeCpzb/BipW5M5gVmRbCb9l/kdYEe8lN9y/bfAuv/BQ bYoEvE/tLa9/eaF6PVlEkQ+sPazw/MwrfUCNNozdxqoJGUfoaIOEKCBrShz1WRyBAVg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590674; 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=DskPNIRZ2ciIgNFu1atw5tCEm9BjI6JeU6DzkiEP+QE=; b=dTfq91sTj1QIgVNvj6q33QD4CKiHAY8WHHo/gjkBzY14TkeHOa0TKXYPspu9PoppY8XE MYbBt9G5caZKqsOdWht2o+n7W7hKU84oyiAZ3u7Ih6JoZgge/oqNrZPUKTHd7qpPs4FkT lrhnKy13612XrX6Pa+ccSN5SQZC+oB7lDPOTF29zYhPMPwjzEoqK16k3uGWyX+fI4QJC9 5NjqjfllNc6ijossm4UN7A1blpRQSjC9X9WKVsF4UqRlkyp3shG0LjOhU7tbgUx2ixEeg ClvV2yeswyTK6q0aS+Vnk9xcF2Ol+dn8lBLNA5+xB3ah6zplgVXjpLuQRE42jYEe0Cw== 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=QfNazaLe; 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 33167606B223; Fri, 13 Nov 2026 17:24:34 +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=QfNazaLe Received: by smtp.kernel.org (Postfix) with ESMTPSA id D41A21F000C4; Fri, 13 Nov 2026 17:24:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590674; bh=DskPNIRZ2ciIgNFu1atw5tCEm9BjI6JeU6DzkiEP+QE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QfNazaLeHwIsqDcZuwcVp6RM94n9MhcAe3avixWMI/JTlZPvG/3eOHlZ05GrADAYN GQweMdHxFQdaE0tYjp6K5Ilo5lZBoXLyQbqKc+/WGZs01lKksoejEM4HuBXAIUogNX oOfFWWaaEqvFR+97ChMW9RHWQgJ9a+ezrtSvZgZg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yuto Ohnuki , Stefan Hajnoczi , Miklos Szeredi , Sasha Levin Subject: [PATCH 6.18 588/686] virtiofs: add FUSE protocol validation Date: Fri, 13 Nov 2026 10:52:01 -0500 Message-ID: <20261113153841.739867657@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: Yuto Ohnuki [ Upstream commit 68b69fa0edb241a946cd4c850110990f30705164 ] Add virtio_fs_verify_response() to validate that the server properly follows the FUSE protocol by checking: - Response length is at least sizeof(struct fuse_out_header). - oh.len matches the actual response length. - oh.unique matches the request's unique identifier. On validation failure, set error to -EIO and normalize oh.len to prevent underflow in copy_args_from_argbuf(). Addresses the TODO comment in virtio_fs_request_complete(). Signed-off-by: Yuto Ohnuki Reviewed-by: Stefan Hajnoczi Signed-off-by: Miklos Szeredi Stable-dep-of: 5364d081125a ("virtiofs: validate fixed-output response length") Signed-off-by: Sasha Levin --- fs/fuse/virtio_fs.c | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-) diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index e475f7f9e83d4..33962e1ad8c12 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -755,6 +755,27 @@ static void copy_args_from_argbuf(struct fuse_args *args, struct fuse_req *req) req->argbuf = NULL; } +/* Verify that the server properly follows the FUSE protocol */ +static bool virtio_fs_verify_response(struct fuse_req *req, unsigned int len) +{ + struct fuse_out_header *oh = &req->out.h; + + if (len < sizeof(*oh)) { + pr_warn("virtio-fs: response too short (%u)\n", len); + return false; + } + if (oh->len != len) { + pr_warn("virtio-fs: oh.len mismatch (%u != %u)\n", oh->len, len); + return false; + } + if (oh->unique != req->in.h.unique) { + pr_warn("virtio-fs: oh.unique mismatch (%llu != %llu)\n", + oh->unique, req->in.h.unique); + return false; + } + return true; +} + /* Work function for request completion */ static void virtio_fs_request_complete(struct fuse_req *req, struct virtio_fs_vq *fsvq) @@ -764,10 +785,6 @@ static void virtio_fs_request_complete(struct fuse_req *req, unsigned int len, i, thislen; struct folio *folio; - /* - * TODO verify that server properly follows FUSE protocol - * (oh.uniq, oh.len) - */ args = req->args; copy_args_from_argbuf(args, req); @@ -821,6 +838,10 @@ static void virtio_fs_requests_done_work(struct work_struct *work) virtqueue_disable_cb(vq); while ((req = virtqueue_get_buf(vq, &len)) != NULL) { + if (!virtio_fs_verify_response(req, len)) { + req->out.h.error = -EIO; + req->out.h.len = sizeof(struct fuse_out_header); + } spin_lock(&fpq->lock); list_move_tail(&req->list, &reqs); spin_unlock(&fpq->lock); -- 2.53.0