From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B2D0C4167B for ; Tue, 22 Nov 2022 02:16:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232577AbiKVCQg (ORCPT ); Mon, 21 Nov 2022 21:16:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42600 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232526AbiKVCQc (ORCPT ); Mon, 21 Nov 2022 21:16:32 -0500 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F61CE3D3A for ; Mon, 21 Nov 2022 18:16:06 -0800 (PST) Received: by mail-yb1-xb4a.google.com with SMTP id y82-20020a253255000000b006e7a04f3824so11779260yby.19 for ; Mon, 21 Nov 2022 18:16:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=w2q3Pe5xMPw4X/9LVfd4DivdDutjiK3KnsX8KQ2N8hg=; b=aTBA/4JqNfwuIeF/z6qbwtHTisSmHirpljRg/jqvop/zWE55jxwONCGDNplDOvHIUW EdpMWtBWdM/Q73DKy22ZiPzuWMZIje8JjbI6oo1SzHSUA74BDWub9IHwW0c1jTUAMbyG qOkCaE9aSL9MCjO6dYMB9PFb0aSX8Hfbqe2UBhcL5iq8ZkRxKNPjQ5ioSBSVeFYk0Qqm Z6DISHRrhTLBKncu7nRqFeA8S3zpz179cTjAmXPcklE8oU9QjNuSHkGrM1Ep/EIROqyT +Xu7VQDk/YnBsHGQZGJERKD3mSGCPFH4bds3NFKtzGnpePnm86694b/7JnzRw2PKb2tW dKoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=w2q3Pe5xMPw4X/9LVfd4DivdDutjiK3KnsX8KQ2N8hg=; b=l+3wr9SpGpMpYHJah+h09HhPuKFUOETZBJCsfJPsN5Vox71xfWOr/Urx45cwy7bm/N Y7EBqxtnGWc6xgiiIz/bSUkdFMBrIpSXqAKU6g/AjOUu7fDEPVm+99X7pw5KD5VtcVnh lwBwWQFF1wEfPtYAY8RvrA0QU4RROGXr/bB0qiLFv3fLnDD2ZcbkiPaRplvVKH0rdd90 TtE5BlwCHHfYW8fw835EIjWAl4pYaX7cNPt2hLk/D60dvcmcN7xcHDtRBdsfna+DEopP OSQxFfsjXyEbjfdqbnI++xy9ct0B0qFtoM9BOkuNKac3Q0rN/g8oxSM/5Y+pkngZTk+B mkcQ== X-Gm-Message-State: ANoB5pnG37vyfuW+NIsGmpaLRzwMLjaGkXeuioz8Ulb/FM4ogYvUy8zq 1/xex6ZXB4LsD2faFd4RQ1+quGkpA44= X-Google-Smtp-Source: AA0mqf56By5tkbMPbE3+8HlVejJa2CcHXpyOQFp8e5Hw5P5xL8vmWpfR7zoKgiNxYfs8ibJqKjx+X/YrEyo= X-Received: from drosen.mtv.corp.google.com ([2620:15c:211:200:8539:aadd:13be:6e82]) (user=drosen job=sendgmr) by 2002:a81:47c2:0:b0:388:7d2:587b with SMTP id u185-20020a8147c2000000b0038807d2587bmr3633337ywa.416.1669083365933; Mon, 21 Nov 2022 18:16:05 -0800 (PST) Date: Mon, 21 Nov 2022 18:15:20 -0800 In-Reply-To: <20221122021536.1629178-1-drosen@google.com> Mime-Version: 1.0 References: <20221122021536.1629178-1-drosen@google.com> X-Mailer: git-send-email 2.38.1.584.g0f3c55d4c2-goog Message-ID: <20221122021536.1629178-6-drosen@google.com> Subject: [RFC PATCH v2 05/21] fuse-bpf: Add ioctl interface for /dev/fuse From: Daniel Rosenberg To: Miklos Szeredi Cc: Amir Goldstein , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org, bpf@vger.kernel.org, kernel-team@android.com, Daniel Rosenberg Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org This introduces an alternative method of responding to fuse requests. Lookups supplying a backing fd or bpf will need to call through the ioctl to ensure there can be no attempts to fool priveledged processes into inadvertantly performing other actions. Signed-off-by: Daniel Rosenberg --- fs/fuse/dev.c | 56 ++++++++++++++++++++++++++++++++------- fs/fuse/fuse_i.h | 1 + include/uapi/linux/fuse.h | 1 + 3 files changed, 48 insertions(+), 10 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 79d2fb6adc83..fbc519c37e66 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1013,18 +1013,19 @@ static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) /* Copy the fuse-bpf lookup args and verify them */ #ifdef CONFIG_FUSE_BPF -static int fuse_copy_lookup(struct fuse_copy_state *cs, void *val, unsigned size) +static int fuse_copy_lookup(struct fuse_copy_state *cs, unsigned via_ioctl, void *val, unsigned size) { struct fuse_bpf_entry_out *fbeo = (struct fuse_bpf_entry_out *)val; struct fuse_bpf_entry *feb = container_of(fbeo, struct fuse_bpf_entry, out[0]); int num_entries = size / sizeof(*fbeo); int err; - if (size && size % sizeof(*fbeo) != 0) + if (size && (size % sizeof(*fbeo) != 0 || !via_ioctl)) return -EINVAL; if (num_entries > FUSE_BPF_MAX_ENTRIES) return -EINVAL; + err = fuse_copy_one(cs, val, size); if (err) return err; @@ -1033,7 +1034,7 @@ static int fuse_copy_lookup(struct fuse_copy_state *cs, void *val, unsigned size return err; } #else -static int fuse_copy_lookup(struct fuse_copy_state *cs, void *val, unsigned size) +static int fuse_copy_lookup(struct fuse_copy_state *cs, unsigned via_ioctl, void *val, unsigned size) { return fuse_copy_one(cs, val, size); } @@ -1042,7 +1043,7 @@ static int fuse_copy_lookup(struct fuse_copy_state *cs, void *val, unsigned size /* Copy request arguments to/from userspace buffer */ static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, unsigned argpages, struct fuse_arg *args, - int zeroing, unsigned is_lookup) + int zeroing, unsigned is_lookup, unsigned via_ioct) { int err = 0; unsigned i; @@ -1052,7 +1053,7 @@ static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, if (i == numargs - 1 && argpages) err = fuse_copy_pages(cs, arg->size, zeroing); else if (i == numargs - 1 && is_lookup) - err = fuse_copy_lookup(cs, arg->value, arg->size); + err = fuse_copy_lookup(cs, via_ioct, arg->value, arg->size); else err = fuse_copy_one(cs, arg->value, arg->size); } @@ -1330,7 +1331,7 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h)); if (!err) err = fuse_copy_args(cs, args->in_numargs, args->in_pages, - (struct fuse_arg *) args->in_args, 0, 0); + (struct fuse_arg *) args->in_args, 0, 0, 0); fuse_copy_finish(cs); spin_lock(&fpq->lock); clear_bit(FR_LOCKED, &req->flags); @@ -1869,7 +1870,8 @@ static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args, lastarg->size -= diffsize; } return fuse_copy_args(cs, args->out_numargs, args->out_pages, - args->out_args, args->page_zeroing, args->is_lookup); + args->out_args, args->page_zeroing, args->is_lookup, + args->via_ioctl); } /* @@ -1879,7 +1881,7 @@ static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args, * it from the list and copy the rest of the buffer to the request. * The request is finished by calling fuse_request_end(). */ -static ssize_t fuse_dev_do_write(struct fuse_dev *fud, +static ssize_t fuse_dev_do_write(struct fuse_dev *fud, bool from_ioctl, struct fuse_copy_state *cs, size_t nbytes) { int err; @@ -1951,6 +1953,7 @@ static ssize_t fuse_dev_do_write(struct fuse_dev *fud, if (!req->args->page_replace) cs->move_pages = 0; + req->args->via_ioctl = from_ioctl; if (oh.error) err = nbytes != sizeof(oh) ? -EINVAL : 0; else @@ -1989,7 +1992,7 @@ static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from) fuse_copy_init(&cs, 0, from); - return fuse_dev_do_write(fud, &cs, iov_iter_count(from)); + return fuse_dev_do_write(fud, false, &cs, iov_iter_count(from)); } static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, @@ -2070,7 +2073,7 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, if (flags & SPLICE_F_MOVE) cs.move_pages = 1; - ret = fuse_dev_do_write(fud, &cs, len); + ret = fuse_dev_do_write(fud, false, &cs, len); pipe_lock(pipe); out_free: @@ -2283,6 +2286,33 @@ static int fuse_device_clone(struct fuse_conn *fc, struct file *new) return 0; } +// Provides an alternate means to respond to a fuse request +static int fuse_handle_ioc_response(struct fuse_dev *dev, void *buff, uint32_t size) +{ + struct fuse_copy_state cs; + struct iovec *iov = NULL; + struct iov_iter iter; + int res; + + if (size > PAGE_SIZE) + return -EINVAL; + iov = (struct iovec *) __get_free_page(GFP_KERNEL); + if (!iov) + return -ENOMEM; + + iov->iov_base = buff; + iov->iov_len = size; + + iov_iter_init(&iter, READ, iov, 1, size); + fuse_copy_init(&cs, 0, &iter); + + + res = fuse_dev_do_write(dev, true, &cs, size); + free_page((unsigned long) iov); + + return res; +} + static long fuse_dev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -2316,6 +2346,12 @@ static long fuse_dev_ioctl(struct file *file, unsigned int cmd, } break; default: + if (_IOC_TYPE(cmd) == FUSE_DEV_IOC_MAGIC + && _IOC_NR(cmd) == _IOC_NR(FUSE_DEV_IOC_BPF_RESPONSE(0)) + && _IOC_DIR(cmd) == _IOC_WRITE) { + res = fuse_handle_ioc_response(fuse_get_dev(file), (void *) arg, _IOC_SIZE(cmd)); + break; + } res = -ENOTTY; break; } diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index d67325af5e72..3452530aba94 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -314,6 +314,7 @@ struct fuse_args { bool page_replace:1; bool may_block:1; bool is_lookup:1; + bool via_ioctl:1; struct fuse_in_arg in_args[3]; struct fuse_arg out_args[2]; void (*end)(struct fuse_mount *fm, struct fuse_args *args, int error); diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index 0e19076729d9..e49e5a8e044c 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -972,6 +972,7 @@ struct fuse_notify_retrieve_in { /* Device ioctls: */ #define FUSE_DEV_IOC_MAGIC 229 #define FUSE_DEV_IOC_CLONE _IOR(FUSE_DEV_IOC_MAGIC, 0, uint32_t) +#define FUSE_DEV_IOC_BPF_RESPONSE(N) _IOW(FUSE_DEV_IOC_MAGIC, 125, char[N]) struct fuse_lseek_in { uint64_t fh; -- 2.38.1.584.g0f3c55d4c2-goog