> From: Christian Brauner <christian.brauner@xxxxxxxxxx>
>
> It's great that the new in-kernel ksmbd server will support idmapped mounts out of the box! However,
> lookup is currently broken. Lookup helpers such as lookup_one_len() call inode_permission() internally
> to ensure that the caller is privileged over the inode of the base dentry they are trying to lookup
> under. So the permission checking here is currently wrong.
>
> Linux v5.15 will gain a new lookup helper lookup_one() that does take idmappings into account. I've
> added it as part of my patch series to make btrfs support idmapped mounts. The new helper is in linux-
> next as part of David's (Sterba) btrfs for-next branch as commit c972214c133b ("namei: add mapping
> aware lookup helper").
>
> I've said it before during one of my first reviews: I would very much recommend adding fstests to [1].
> It already seems to have very rudimentary cifs support. There is a completely generic idmapped mount
> testsuite that supports idmapped mounts.
>
> [1]: https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git/
> Cc: Steve French <stfrench@xxxxxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> Cc: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
> Cc: Hyunchul Lee <hyc.lee@xxxxxxxxx>
> Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> Cc: David Sterba <dsterba@xxxxxxxx>
> Cc: linux-cifs@xxxxxxxxxxxxxxx
> Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
> ---
Hi Christian,
> I merged David's for-next tree into cifsd-next to test this. I did only compile test this. If someone
> gives me a clear set of instructions how to test ksmbd on my local machine I can at least try to cut
> some time out of my week to do more reviews. (I'd especially like to see acl behavior with ksmbd.)
There is "How to run ksmbd" section in patch cover letter.
https://lkml.org/lkml/2021/8/5/54
Let me know if it doesn't work well even if you try to run it with this step.
And We will also check whether your patch work fine.
>
> One more thing, the tree for ksmbd was very hard to find. I had to do a lot archeology to end up at:
>
> git://git.samba.org/ksmbd.git
This is also in the patch cover letter. See "Mailing list and repositories" section.
I think that you can use :
https://github.com/namjaejeon/smb3-kernel/tree/ksmbd-v7-series
>
> Would be appreciated if this tree could be reflected in MAINTAINERS or somewhere else. The github
> repos with the broken out patches/module aren't really that helpful.
Okay, I will add git address of ksmbd in MAINTAINERS on next spin.
>
> Thanks!
> Christian
Really thanks for your review and I will apply this patch after checking it.
> ---
> fs/ksmbd/smb2pdu.c | 18 +++++++++++-------
> fs/ksmbd/vfs.c | 43 ++++++++++++++++++++++++-------------------
> fs/ksmbd/vfs.h | 3 ++-
> 3 files changed, 37 insertions(+), 27 deletions(-)
>
> diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c index 636570ecfa31..9a1a9a024714 100644
> --- a/fs/ksmbd/smb2pdu.c
> +++ b/fs/ksmbd/smb2pdu.c
> @@ -3539,9 +3539,9 @@ static int process_query_dir_entries(struct smb2_query_dir_private *priv)
> return -EINVAL;
>
> lock_dir(priv->dir_fp);
> - dent = lookup_one_len(priv->d_info->name,
> - priv->dir_fp->filp->f_path.dentry,
> - priv->d_info->name_len);
> + dent = lookup_one(user_ns, priv->d_info->name,
> + priv->dir_fp->filp->f_path.dentry,
> + priv->d_info->name_len);
> unlock_dir(priv->dir_fp);
>
> if (IS_ERR(dent)) {
> @@ -5242,7 +5242,9 @@ int smb2_echo(struct ksmbd_work *work)
> return 0;
> }
>
> -static int smb2_rename(struct ksmbd_work *work, struct ksmbd_file *fp,
> +static int smb2_rename(struct ksmbd_work *work,
> + struct ksmbd_file *fp,
> + struct user_namespace *user_ns,
> struct smb2_file_rename_info *file_info,
> struct nls_table *local_nls)
> {
> @@ -5306,7 +5308,7 @@ static int smb2_rename(struct ksmbd_work *work, struct ksmbd_file *fp,
> if (rc)
> goto out;
>
> - rc = ksmbd_vfs_setxattr(file_mnt_user_ns(fp->filp),
> + rc = ksmbd_vfs_setxattr(user_ns,
> fp->filp->f_path.dentry,
> xattr_stream_name,
> NULL, 0, 0);
> @@ -5620,6 +5622,7 @@ static int set_end_of_file_info(struct ksmbd_work *work, struct ksmbd_file *fp,
> static int set_rename_info(struct ksmbd_work *work, struct ksmbd_file *fp,
> char *buf)
> {
> + struct user_namespace *user_ns;
> struct ksmbd_file *parent_fp;
> struct dentry *parent;
> struct dentry *dentry = fp->filp->f_path.dentry; @@ -5633,8 +5636,9 @@ static int
> set_rename_info(struct ksmbd_work *work, struct ksmbd_file *fp,
> if (ksmbd_stream_fd(fp))
> goto next;
>
> + user_ns = file_mnt_user_ns(fp->filp);
> parent = dget_parent(dentry);
> - ret = ksmbd_vfs_lock_parent(parent, dentry);
> + ret = ksmbd_vfs_lock_parent(user_ns, parent, dentry);
> if (ret) {
> dput(parent);
> return ret;
> @@ -5651,7 +5655,7 @@ static int set_rename_info(struct ksmbd_work *work, struct ksmbd_file *fp,
> }
> }
> next:
> - return smb2_rename(work, fp,
> + return smb2_rename(work, fp, user_ns,
> (struct smb2_file_rename_info *)buf,
> work->sess->conn->local_nls);
> }
> diff --git a/fs/ksmbd/vfs.c b/fs/ksmbd/vfs.c index 612c52d7a01b..8000ea3ade10 100644
> --- a/fs/ksmbd/vfs.c
> +++ b/fs/ksmbd/vfs.c
> @@ -69,14 +69,15 @@ static void ksmbd_vfs_inherit_owner(struct ksmbd_work *work,
> *
> * the reference count of @parent isn't incremented.
> */
> -int ksmbd_vfs_lock_parent(struct dentry *parent, struct dentry *child)
> +int ksmbd_vfs_lock_parent(struct user_namespace *user_ns, struct dentry *parent,
> + struct dentry *child)
> {
> struct dentry *dentry;
> int ret = 0;
>
> inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
> - dentry = lookup_one_len(child->d_name.name, parent,
> - child->d_name.len);
> + dentry = lookup_one(user_ns, child->d_name.name, parent,
> + child->d_name.len);
> if (IS_ERR(dentry)) {
> ret = PTR_ERR(dentry);
> goto out_err;
> @@ -102,7 +103,7 @@ int ksmbd_vfs_may_delete(struct user_namespace *user_ns,
> int ret;
>
> parent = dget_parent(dentry);
> - ret = ksmbd_vfs_lock_parent(parent, dentry);
> + ret = ksmbd_vfs_lock_parent(user_ns, parent, dentry);
> if (ret) {
> dput(parent);
> return ret;
> @@ -137,7 +138,7 @@ int ksmbd_vfs_query_maximal_access(struct user_namespace *user_ns,
> *daccess |= FILE_EXECUTE_LE;
>
> parent = dget_parent(dentry);
> - ret = ksmbd_vfs_lock_parent(parent, dentry);
> + ret = ksmbd_vfs_lock_parent(user_ns, parent, dentry);
> if (ret) {
> dput(parent);
> return ret;
> @@ -197,6 +198,7 @@ int ksmbd_vfs_create(struct ksmbd_work *work, const char *name, umode_t mode)
> */
> int ksmbd_vfs_mkdir(struct ksmbd_work *work, const char *name, umode_t mode) {
> + struct user_namespace *user_ns;
> struct path path;
> struct dentry *dentry;
> int err;
> @@ -210,16 +212,16 @@ int ksmbd_vfs_mkdir(struct ksmbd_work *work, const char *name, umode_t mode)
> return err;
> }
>
> + user_ns = mnt_user_ns(path.mnt);
> mode |= S_IFDIR;
> - err = vfs_mkdir(mnt_user_ns(path.mnt), d_inode(path.dentry),
> - dentry, mode);
> + err = vfs_mkdir(user_ns, d_inode(path.dentry), dentry, mode);
> if (err) {
> goto out;
> } else if (d_unhashed(dentry)) {
> struct dentry *d;
>
> - d = lookup_one_len(dentry->d_name.name, dentry->d_parent,
> - dentry->d_name.len);
> + d = lookup_one(user_ns, dentry->d_name.name, dentry->d_parent,
> + dentry->d_name.len);
> if (IS_ERR(d)) {
> err = PTR_ERR(d);
> goto out;
> @@ -582,6 +584,7 @@ int ksmbd_vfs_fsync(struct ksmbd_work *work, u64 fid, u64 p_id)
> */
> int ksmbd_vfs_remove_file(struct ksmbd_work *work, char *name) {
> + struct user_namespace *user_ns;
> struct path path;
> struct dentry *parent;
> int err;
> @@ -601,8 +604,9 @@ int ksmbd_vfs_remove_file(struct ksmbd_work *work, char *name)
> return err;
> }
>
> + user_ns = mnt_user_ns(path.mnt);
> parent = dget_parent(path.dentry);
> - err = ksmbd_vfs_lock_parent(parent, path.dentry);
> + err = ksmbd_vfs_lock_parent(user_ns, parent, path.dentry);
> if (err) {
> dput(parent);
> path_put(&path);
> @@ -616,14 +620,12 @@ int ksmbd_vfs_remove_file(struct ksmbd_work *work, char *name)
> }
>
> if (S_ISDIR(d_inode(path.dentry)->i_mode)) {
> - err = vfs_rmdir(mnt_user_ns(path.mnt), d_inode(parent),
> - path.dentry);
> + err = vfs_rmdir(user_ns, d_inode(parent), path.dentry);
> if (err && err != -ENOTEMPTY)
> ksmbd_debug(VFS, "%s: rmdir failed, err %d\n", name,
> err);
> } else {
> - err = vfs_unlink(mnt_user_ns(path.mnt), d_inode(parent),
> - path.dentry, NULL);
> + err = vfs_unlink(user_ns, d_inode(parent), path.dentry, NULL);
> if (err)
> ksmbd_debug(VFS, "%s: unlink failed, err %d\n", name,
> err);
> @@ -748,7 +750,8 @@ static int __ksmbd_vfs_rename(struct ksmbd_work *work,
> if (ksmbd_override_fsids(work))
> return -ENOMEM;
>
> - dst_dent = lookup_one_len(dst_name, dst_dent_parent, strlen(dst_name));
> + dst_dent = lookup_one(dst_user_ns, dst_name, dst_dent_parent,
> + strlen(dst_name));
> err = PTR_ERR(dst_dent);
> if (IS_ERR(dst_dent)) {
> pr_err("lookup failed %s [%d]\n", dst_name, err); @@ -779,6 +782,7 @@ static int
> __ksmbd_vfs_rename(struct ksmbd_work *work, int ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct
> ksmbd_file *fp,
> char *newname)
> {
> + struct user_namespace *user_ns;
> struct path dst_path;
> struct dentry *src_dent_parent, *dst_dent_parent;
> struct dentry *src_dent, *trap_dent, *src_child; @@ -808,8 +812,9 @@ int
> ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct ksmbd_file *fp,
> trap_dent = lock_rename(src_dent_parent, dst_dent_parent);
> dget(src_dent);
> dget(dst_dent_parent);
> - src_child = lookup_one_len(src_dent->d_name.name, src_dent_parent,
> - src_dent->d_name.len);
> + user_ns = file_mnt_user_ns(fp->filp);
> + src_child = lookup_one(user_ns, src_dent->d_name.name, src_dent_parent,
> + src_dent->d_name.len);
> if (IS_ERR(src_child)) {
> err = PTR_ERR(src_child);
> goto out_lock;
> @@ -823,7 +828,7 @@ int ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct ksmbd_file *fp,
> dput(src_child);
>
> err = __ksmbd_vfs_rename(work,
> - file_mnt_user_ns(fp->filp),
> + user_ns,
> src_dent_parent,
> src_dent,
> mnt_user_ns(dst_path.mnt),
> @@ -1109,7 +1114,7 @@ int ksmbd_vfs_unlink(struct user_namespace *user_ns, {
> int err = 0;
>
> - err = ksmbd_vfs_lock_parent(dir, dentry);
> + err = ksmbd_vfs_lock_parent(user_ns, dir, dentry);
> if (err)
> return err;
> dget(dentry);
> diff --git a/fs/ksmbd/vfs.h b/fs/ksmbd/vfs.h index cb0cba0d5d07..85db50abdb24 100644
> --- a/fs/ksmbd/vfs.h
> +++ b/fs/ksmbd/vfs.h
> @@ -107,7 +107,8 @@ struct ksmbd_kstat {
> __le32 file_attributes;
> };
>
> -int ksmbd_vfs_lock_parent(struct dentry *parent, struct dentry *child);
> +int ksmbd_vfs_lock_parent(struct user_namespace *user_ns, struct dentry *parent,
> + struct dentry *child);
> int ksmbd_vfs_may_delete(struct user_namespace *user_ns, struct dentry *dentry); int
> ksmbd_vfs_query_maximal_access(struct user_namespace *user_ns,
> struct dentry *dentry, __le32 *daccess);
>
> base-commit: 456af438ad490bac7ed954cb929bcec1df7f0c82
> --
> 2.30.2
