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=1794591464; b=kLC9Oe4YPKZPya9uuzFYuNIsQYDcVCSub+04k9x5WsK0+9ffvfX0YN05GguDyDoEjCT5 4efaZbL0WtMOCBLa1SmXVzLejRu9eLBttHP5+r24/5L/KiLt3F5pu17i8v3iEkTqezpcD eOfawB1pt5Kwv9JO987j2m38R0F+cPqWjsdpoa/zjbV+T4ihj1tQ9nFmhf553WJFSW+ll DoQFZsc+SeXcE66o8U+aRLto2bazGoiGhtYJMxEbzaGmW5Hi2QQfmtv2pyhp3IHN0yvxv ZINwSAdOzAN8bLRmgqCwroFZocqiWbR0S/03xwbL5uVhsPXn8PjWYa+Yx5RDYu4UhXA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794591464; 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=U3Xhniee56dqMSVBEAd420wGEA87TgkdN1nDsvbHYWA=; b=zW17lrtVmCyBiYhTzdS4rolLRUc6Hme2HTz7IOmqXAoGkH8D84Tcxd8FSnKm36xghix7 in7pwxOYyB7vxOpADi6DWmUcHph2AIutNkyyNLLV6036mqutW4R853yw+9Lb9td1e0E8N Ny3vPAHvvyOiLFkSr2mG86lx5tMRRev6141UeU1xeBo2qozagA70ruKDbZ2QztrYR5TYh BCZHgcoZNKkxyuGPew2W45LGfrkp65te++Xo4GoFs/UX9k0mFespfSp9otVs0gzXTykyE 6y7nQfI3Hmro2hLHR5g5yaIUgp+KRTEH8QQYGppe7pXZtyxHhlapBO9zLFE882eoLGQ== 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=HotNc4yO; 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 CF9F4606E20B; Fri, 13 Nov 2026 17:37:44 +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=HotNc4yO Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7BDA51F000C4; Fri, 13 Nov 2026 17:37:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794591464; bh=U3Xhniee56dqMSVBEAd420wGEA87TgkdN1nDsvbHYWA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HotNc4yOMwfQwGUroN/6Z0gnrVvhuX7BpdCQDDsQOPMt3Mqd/U5sjV/5MeQwBLdcL E0Dsdi/fguP77lIM7OjjA3IWqBZlERoQ0mKlLGB3vX6kOHyRdmFLDYy3vQ8gFOx+Kt KHriD0Jvue28wNSCPs8zZd+5Pd4z2KrL5VbpNJOo= 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 6.12 549/670] virtiofs: add FUSE protocol validation Date: Fri, 13 Nov 2026 10:51:53 -0500 Message-ID: <20261113153830.491221235@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153811.177190860@linuxfoundation.org> References: <20261113153811.177190860@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 6.12-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 06e59b820ffa8..0d076cbd94237 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -749,6 +749,27 @@ 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) @@ -759,10 +780,6 @@ static void virtio_fs_request_complete(struct fuse_req *req, unsigned int len, i, thislen; struct page *page; - /* - * TODO verify that server properly follows FUSE protocol - * (oh.uniq, oh.len) - */ args = req->args; copy_args_from_argbuf(args, req); @@ -818,6 +835,10 @@ 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