From patchwork Sun Jul 16 16:23:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namjae Jeon X-Patchwork-Id: 13314842 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 E2947EB64DD for ; Sun, 16 Jul 2023 16:23:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229495AbjGPQXc (ORCPT ); Sun, 16 Jul 2023 12:23:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229461AbjGPQXc (ORCPT ); Sun, 16 Jul 2023 12:23:32 -0400 Received: from mail-pf1-f176.google.com (mail-pf1-f176.google.com [209.85.210.176]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC9FD116 for ; Sun, 16 Jul 2023 09:23:30 -0700 (PDT) Received: by mail-pf1-f176.google.com with SMTP id d2e1a72fcca58-66f3fc56ef4so2908564b3a.0 for ; Sun, 16 Jul 2023 09:23:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689524610; x=1692116610; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=DaiCL3REeO13M1Zgv3mn+JDPGhHQevpnhTnfyenMC1I=; b=HncQSG9KRrm4y+FzDXdYnpFPLp0M+ullXeeRTZo4KdPNizXfPIaLK+fdDa4xixHkQP lANX6IH5sYlL2ecxrcNq67FuJmoP+rjLFPSqQLWlc6P/at2HxL8eZKxcHKZylZ8k31ks rc+vfpA30NzZpvZsF4wnW+rtRjHYvgTi4JY9XBo2ifUnqktCBUT0g6OCrXGl+JHAD4i9 2HNITMim/bfLw5QAcYtIAgJSKz7IUFKuUA9Asas6uRIbAoF3LiThYw+2T6FlPoA7rSqG w/h0zjIrtIYKVesF2fQA/xa6zroF++8xW5/98WaKAJJEbeVkgwyolU26uwJW+izEYIjx CAcA== X-Gm-Message-State: ABy/qLZEzRnXAnk0ye4IoBJ1eMov3GTxphYRmYaultKCkfeooMCrt2Pc ckRrypWZD2JkYu+CjnQCBAgiwBZxtYw= X-Google-Smtp-Source: APBJJlF5loRTR7EkLtGxI3XXWFjVs+gTIs6v2QYYZxnMje7BZ4+PLra27llcTejOzYfBqIHXEwI3hA== X-Received: by 2002:a17:902:cece:b0:1ae:6947:e63b with SMTP id d14-20020a170902cece00b001ae6947e63bmr9529790plg.16.1689524610107; Sun, 16 Jul 2023 09:23:30 -0700 (PDT) Received: from localhost.localdomain ([211.49.23.9]) by smtp.gmail.com with ESMTPSA id l3-20020a170902cf8300b001b9ce2c3baesm11171821ply.143.2023.07.16.09.23.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 16 Jul 2023 09:23:29 -0700 (PDT) From: Namjae Jeon To: linux-cifs@vger.kernel.org Cc: smfrench@gmail.com, senozhatsky@chromium.org, tom@talpey.com, hyc.lee@gmail.com, atteh.mailbox@gmail.com, Namjae Jeon , Steve French Subject: [PATCH v2] ksmbd: check if a mount point is crossed during path lookup Date: Mon, 17 Jul 2023 01:23:13 +0900 Message-Id: <20230716162313.4642-1-linkinjeon@kernel.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Since commit 74d7970febf7 ("ksmbd: fix racy issue from using ->d_parent and ->d_name"), ksmbd can not lookup cross mount points. If last component is a cross mount point during path lookup, check if it is crossed to follow it down. And allow path lookup to cross a mount point when a crossmnt parameter is set to 'yes' in smb.conf. Fixes: 74d7970febf7 ("ksmbd: fix racy issue from using ->d_parent and ->d_name") Signed-off-by: Namjae Jeon Signed-off-by: Steve French --- v2: - allow path lookup to cross a mount point when a crossmnt parameter is set to 'yes' in smb.conf fs/smb/server/smb2pdu.c | 27 +++++++++++-------- fs/smb/server/vfs.c | 58 +++++++++++++++++++++++------------------ fs/smb/server/vfs.h | 4 +-- 3 files changed, 51 insertions(+), 38 deletions(-) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index cf8822103f50..ca276634fd58 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -2467,8 +2467,9 @@ static void smb2_update_xattrs(struct ksmbd_tree_connect *tcon, } } -static int smb2_creat(struct ksmbd_work *work, struct path *path, char *name, - int open_flags, umode_t posix_mode, bool is_dir) +static int smb2_creat(struct ksmbd_work *work, struct path *parent_path, + struct path *path, char *name, int open_flags, + umode_t posix_mode, bool is_dir) { struct ksmbd_tree_connect *tcon = work->tcon; struct ksmbd_share_config *share = tcon->share_conf; @@ -2495,7 +2496,7 @@ static int smb2_creat(struct ksmbd_work *work, struct path *path, char *name, return rc; } - rc = ksmbd_vfs_kern_path_locked(work, name, 0, path, 0); + rc = ksmbd_vfs_kern_path_locked(work, name, 0, parent_path, path, 0); if (rc) { pr_err("cannot get linux path (%s), err = %d\n", name, rc); @@ -2565,7 +2566,7 @@ int smb2_open(struct ksmbd_work *work) struct ksmbd_tree_connect *tcon = work->tcon; struct smb2_create_req *req; struct smb2_create_rsp *rsp; - struct path path; + struct path path, parent_path; struct ksmbd_share_config *share = tcon->share_conf; struct ksmbd_file *fp = NULL; struct file *filp = NULL; @@ -2786,7 +2787,8 @@ int smb2_open(struct ksmbd_work *work) goto err_out1; } - rc = ksmbd_vfs_kern_path_locked(work, name, LOOKUP_NO_SYMLINKS, &path, 1); + rc = ksmbd_vfs_kern_path_locked(work, name, LOOKUP_NO_SYMLINKS, + &parent_path, &path, 1); if (!rc) { file_present = true; @@ -2906,7 +2908,8 @@ int smb2_open(struct ksmbd_work *work) /*create file if not present */ if (!file_present) { - rc = smb2_creat(work, &path, name, open_flags, posix_mode, + rc = smb2_creat(work, &parent_path, &path, name, open_flags, + posix_mode, req->CreateOptions & FILE_DIRECTORY_FILE_LE); if (rc) { if (rc == -ENOENT) { @@ -3321,8 +3324,9 @@ int smb2_open(struct ksmbd_work *work) err_out: if (file_present || created) { - inode_unlock(d_inode(path.dentry->d_parent)); - dput(path.dentry); + inode_unlock(d_inode(parent_path.dentry)); + path_put(&path); + path_put(&parent_path); } ksmbd_revert_fsids(work); err_out1: @@ -5545,7 +5549,7 @@ static int smb2_create_link(struct ksmbd_work *work, struct nls_table *local_nls) { char *link_name = NULL, *target_name = NULL, *pathname = NULL; - struct path path; + struct path path, parent_path; bool file_present = false; int rc; @@ -5575,7 +5579,7 @@ static int smb2_create_link(struct ksmbd_work *work, ksmbd_debug(SMB, "target name is %s\n", target_name); rc = ksmbd_vfs_kern_path_locked(work, link_name, LOOKUP_NO_SYMLINKS, - &path, 0); + &parent_path, &path, 0); if (rc) { if (rc != -ENOENT) goto out; @@ -5605,8 +5609,9 @@ static int smb2_create_link(struct ksmbd_work *work, rc = -EINVAL; out: if (file_present) { - inode_unlock(d_inode(path.dentry->d_parent)); + inode_unlock(d_inode(parent_path.dentry)); path_put(&path); + path_put(&parent_path); } if (!IS_ERR(link_name)) kfree(link_name); diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c index e605ee96b0d0..3d5d652153a5 100644 --- a/fs/smb/server/vfs.c +++ b/fs/smb/server/vfs.c @@ -63,13 +63,13 @@ int ksmbd_vfs_lock_parent(struct dentry *parent, struct dentry *child) static int ksmbd_vfs_path_lookup_locked(struct ksmbd_share_config *share_conf, char *pathname, unsigned int flags, + struct path *parent_path, struct path *path) { struct qstr last; struct filename *filename; struct path *root_share_path = &share_conf->vfs_path; int err, type; - struct path parent_path; struct dentry *d; if (pathname[0] == '\0') { @@ -84,7 +84,7 @@ static int ksmbd_vfs_path_lookup_locked(struct ksmbd_share_config *share_conf, return PTR_ERR(filename); err = vfs_path_parent_lookup(filename, flags, - &parent_path, &last, &type, + parent_path, &last, &type, root_share_path); if (err) { putname(filename); @@ -92,13 +92,13 @@ static int ksmbd_vfs_path_lookup_locked(struct ksmbd_share_config *share_conf, } if (unlikely(type != LAST_NORM)) { - path_put(&parent_path); + path_put(parent_path); putname(filename); return -ENOENT; } - inode_lock_nested(parent_path.dentry->d_inode, I_MUTEX_PARENT); - d = lookup_one_qstr_excl(&last, parent_path.dentry, 0); + inode_lock_nested(parent_path->dentry->d_inode, I_MUTEX_PARENT); + d = lookup_one_qstr_excl(&last, parent_path->dentry, 0); if (IS_ERR(d)) goto err_out; @@ -108,15 +108,22 @@ static int ksmbd_vfs_path_lookup_locked(struct ksmbd_share_config *share_conf, } path->dentry = d; - path->mnt = share_conf->vfs_path.mnt; - path_put(&parent_path); - putname(filename); + path->mnt = mntget(parent_path->mnt); + + if (test_share_config_flag(share_conf, KSMBD_SHARE_FLAG_CROSSMNT)) { + err = follow_down(path, 0); + if (err < 0) { + path_put(path); + goto err_out; + } + } + putname(filename); return 0; err_out: - inode_unlock(parent_path.dentry->d_inode); - path_put(&parent_path); + inode_unlock(d_inode(parent_path->dentry)); + path_put(parent_path); putname(filename); return -ENOENT; } @@ -1195,14 +1202,14 @@ static int ksmbd_vfs_lookup_in_dir(const struct path *dir, char *name, * Return: 0 on success, otherwise error */ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name, - unsigned int flags, struct path *path, - bool caseless) + unsigned int flags, struct path *parent_path, + struct path *path, bool caseless) { struct ksmbd_share_config *share_conf = work->tcon->share_conf; int err; - struct path parent_path; - err = ksmbd_vfs_path_lookup_locked(share_conf, name, flags, path); + err = ksmbd_vfs_path_lookup_locked(share_conf, name, flags, parent_path, + path); if (!err) return 0; @@ -1217,10 +1224,10 @@ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name, path_len = strlen(filepath); remain_len = path_len; - parent_path = share_conf->vfs_path; - path_get(&parent_path); + *parent_path = share_conf->vfs_path; + path_get(parent_path); - while (d_can_lookup(parent_path.dentry)) { + while (d_can_lookup(parent_path->dentry)) { char *filename = filepath + path_len - remain_len; char *next = strchrnul(filename, '/'); size_t filename_len = next - filename; @@ -1229,7 +1236,7 @@ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name, if (filename_len == 0) break; - err = ksmbd_vfs_lookup_in_dir(&parent_path, filename, + err = ksmbd_vfs_lookup_in_dir(parent_path, filename, filename_len, work->conn->um); if (err) @@ -1246,8 +1253,8 @@ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name, goto out2; else if (is_last) goto out1; - path_put(&parent_path); - parent_path = *path; + path_put(parent_path); + *parent_path = *path; next[0] = '/'; remain_len -= filename_len + 1; @@ -1255,16 +1262,17 @@ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name, err = -EINVAL; out2: - path_put(&parent_path); + path_put(parent_path); out1: kfree(filepath); } if (!err) { - err = ksmbd_vfs_lock_parent(parent_path.dentry, path->dentry); - if (err) - dput(path->dentry); - path_put(&parent_path); + err = ksmbd_vfs_lock_parent(parent_path->dentry, path->dentry); + if (err) { + path_put(path); + path_put(parent_path); + } } return err; } diff --git a/fs/smb/server/vfs.h b/fs/smb/server/vfs.h index 80039312c255..72f9fb4b48d1 100644 --- a/fs/smb/server/vfs.h +++ b/fs/smb/server/vfs.h @@ -115,8 +115,8 @@ int ksmbd_vfs_xattr_stream_name(char *stream_name, char **xattr_stream_name, int ksmbd_vfs_remove_xattr(struct mnt_idmap *idmap, const struct path *path, char *attr_name); int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name, - unsigned int flags, struct path *path, - bool caseless); + unsigned int flags, struct path *parent_path, + struct path *path, bool caseless); struct dentry *ksmbd_vfs_kern_path_create(struct ksmbd_work *work, const char *name, unsigned int flags,