| Message ID | 20211123114227.3124056-2-brauner@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Extend and tweak mapping support | expand |
On Tue, Nov 23, 2021 at 2:18 PM Christian Brauner <brauner@kernel.org> wrote: > > From: Christian Brauner <christian.brauner@ubuntu.com> > > Multiple places open-code the same check to determine whether a given > mount is idmapped. Introduce a simple helper function that can be used > instead. This allows us to get rid of the fragile open-coding. We will > later change the check that is used to determine whether a given mount > is idmapped. Introducing a helper allows us to do this in a single > place instead of doing it for multiple places. > > Cc: Seth Forshee <sforshee@digitalocean.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Al Viro <viro@zeniv.linux.org.uk> > CC: linux-fsdevel@vger.kernel.org > Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> > --- > fs/cachefiles/bind.c | 2 +- > fs/ecryptfs/main.c | 2 +- > fs/namespace.c | 2 +- > fs/nfsd/export.c | 2 +- > fs/overlayfs/super.c | 2 +- > fs/proc_namespace.c | 2 +- > include/linux/fs.h | 14 ++++++++++++++ > 7 files changed, 20 insertions(+), 6 deletions(-) > > diff --git a/fs/cachefiles/bind.c b/fs/cachefiles/bind.c > index d463d89f5db8..8130142d89c2 100644 > --- a/fs/cachefiles/bind.c > +++ b/fs/cachefiles/bind.c > @@ -117,7 +117,7 @@ static int cachefiles_daemon_add_cache(struct cachefiles_cache *cache) > root = path.dentry; > > ret = -EINVAL; > - if (mnt_user_ns(path.mnt) != &init_user_ns) { > + if (is_mapped_mnt(path.mnt)) { > pr_warn("File cache on idmapped mounts not supported"); > goto error_unsupported; > } > diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c > index d66bbd2df191..331ac3a59515 100644 > --- a/fs/ecryptfs/main.c > +++ b/fs/ecryptfs/main.c > @@ -537,7 +537,7 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags > goto out_free; > } > > - if (mnt_user_ns(path.mnt) != &init_user_ns) { > + if (is_mapped_mnt(path.mnt)) { > rc = -EINVAL; > printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n"); > goto out_free; > diff --git a/fs/namespace.c b/fs/namespace.c > index 659a8f39c61a..7d7b80b375a4 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -3936,7 +3936,7 @@ static int can_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt) > * mapping. It makes things simpler and callers can just create > * another bind-mount they can idmap if they want to. > */ > - if (mnt_user_ns(m) != &init_user_ns) > + if (is_mapped_mnt(m)) > return -EPERM; > > /* The underlying filesystem doesn't support idmapped mounts yet. */ > diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c > index 9421dae22737..292bde9e1eb3 100644 > --- a/fs/nfsd/export.c > +++ b/fs/nfsd/export.c > @@ -427,7 +427,7 @@ static int check_export(struct path *path, int *flags, unsigned char *uuid) > return -EINVAL; > } > > - if (mnt_user_ns(path->mnt) != &init_user_ns) { > + if (is_mapped_mnt(path->mnt)) { > dprintk("exp_export: export of idmapped mounts not yet supported.\n"); > return -EINVAL; > } > diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c > index 265181c110ae..113575fc6155 100644 > --- a/fs/overlayfs/super.c > +++ b/fs/overlayfs/super.c > @@ -873,7 +873,7 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path) > pr_err("filesystem on '%s' not supported\n", name); > goto out_put; > } > - if (mnt_user_ns(path->mnt) != &init_user_ns) { > + if (is_mapped_mnt(path->mnt)) { > pr_err("idmapped layers are currently not supported\n"); > goto out_put; > } > diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c > index 392ef5162655..788c687bb052 100644 > --- a/fs/proc_namespace.c > +++ b/fs/proc_namespace.c > @@ -80,7 +80,7 @@ static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) > seq_puts(m, fs_infop->str); > } > > - if (mnt_user_ns(mnt) != &init_user_ns) > + if (is_mapped_mnt(mnt)) > seq_puts(m, ",idmapped"); > } > > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 1cb616fc1105..192242476b2b 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -2725,6 +2725,20 @@ static inline struct user_namespace *file_mnt_user_ns(struct file *file) > { > return mnt_user_ns(file->f_path.mnt); > } > + > +/** > + * is_mapped_mnt - check whether a mount is mapped > + * @mnt: the mount to check > + * > + * If @mnt has an idmapping attached to it @mnt is mapped. > + * > + * Return: true if mount is mapped, false if not. > + */ > +static inline bool is_mapped_mnt(const struct vfsmount *mnt) > +{ > + return mnt_user_ns(mnt) != &init_user_ns; > +} > + Maybe is_idmapped_mnt? Thanks, Amir.
On Tue, Nov 30, 2021 at 08:25:40AM +0200, Amir Goldstein wrote: > On Tue, Nov 23, 2021 at 2:18 PM Christian Brauner <brauner@kernel.org> wrote: > > > > From: Christian Brauner <christian.brauner@ubuntu.com> > > > > Multiple places open-code the same check to determine whether a given > > mount is idmapped. Introduce a simple helper function that can be used > > instead. This allows us to get rid of the fragile open-coding. We will > > later change the check that is used to determine whether a given mount > > is idmapped. Introducing a helper allows us to do this in a single > > place instead of doing it for multiple places. > > > > Cc: Seth Forshee <sforshee@digitalocean.com> > > Cc: Christoph Hellwig <hch@lst.de> > > Cc: Al Viro <viro@zeniv.linux.org.uk> > > CC: linux-fsdevel@vger.kernel.org > > Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> > > --- > > fs/cachefiles/bind.c | 2 +- > > fs/ecryptfs/main.c | 2 +- > > fs/namespace.c | 2 +- > > fs/nfsd/export.c | 2 +- > > fs/overlayfs/super.c | 2 +- > > fs/proc_namespace.c | 2 +- > > include/linux/fs.h | 14 ++++++++++++++ > > 7 files changed, 20 insertions(+), 6 deletions(-) > > > > diff --git a/fs/cachefiles/bind.c b/fs/cachefiles/bind.c > > index d463d89f5db8..8130142d89c2 100644 > > --- a/fs/cachefiles/bind.c > > +++ b/fs/cachefiles/bind.c > > @@ -117,7 +117,7 @@ static int cachefiles_daemon_add_cache(struct cachefiles_cache *cache) > > root = path.dentry; > > > > ret = -EINVAL; > > - if (mnt_user_ns(path.mnt) != &init_user_ns) { > > + if (is_mapped_mnt(path.mnt)) { > > pr_warn("File cache on idmapped mounts not supported"); > > goto error_unsupported; > > } > > diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c > > index d66bbd2df191..331ac3a59515 100644 > > --- a/fs/ecryptfs/main.c > > +++ b/fs/ecryptfs/main.c > > @@ -537,7 +537,7 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags > > goto out_free; > > } > > > > - if (mnt_user_ns(path.mnt) != &init_user_ns) { > > + if (is_mapped_mnt(path.mnt)) { > > rc = -EINVAL; > > printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n"); > > goto out_free; > > diff --git a/fs/namespace.c b/fs/namespace.c > > index 659a8f39c61a..7d7b80b375a4 100644 > > --- a/fs/namespace.c > > +++ b/fs/namespace.c > > @@ -3936,7 +3936,7 @@ static int can_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt) > > * mapping. It makes things simpler and callers can just create > > * another bind-mount they can idmap if they want to. > > */ > > - if (mnt_user_ns(m) != &init_user_ns) > > + if (is_mapped_mnt(m)) > > return -EPERM; > > > > /* The underlying filesystem doesn't support idmapped mounts yet. */ > > diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c > > index 9421dae22737..292bde9e1eb3 100644 > > --- a/fs/nfsd/export.c > > +++ b/fs/nfsd/export.c > > @@ -427,7 +427,7 @@ static int check_export(struct path *path, int *flags, unsigned char *uuid) > > return -EINVAL; > > } > > > > - if (mnt_user_ns(path->mnt) != &init_user_ns) { > > + if (is_mapped_mnt(path->mnt)) { > > dprintk("exp_export: export of idmapped mounts not yet supported.\n"); > > return -EINVAL; > > } > > diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c > > index 265181c110ae..113575fc6155 100644 > > --- a/fs/overlayfs/super.c > > +++ b/fs/overlayfs/super.c > > @@ -873,7 +873,7 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path) > > pr_err("filesystem on '%s' not supported\n", name); > > goto out_put; > > } > > - if (mnt_user_ns(path->mnt) != &init_user_ns) { > > + if (is_mapped_mnt(path->mnt)) { > > pr_err("idmapped layers are currently not supported\n"); > > goto out_put; > > } > > diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c > > index 392ef5162655..788c687bb052 100644 > > --- a/fs/proc_namespace.c > > +++ b/fs/proc_namespace.c > > @@ -80,7 +80,7 @@ static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) > > seq_puts(m, fs_infop->str); > > } > > > > - if (mnt_user_ns(mnt) != &init_user_ns) > > + if (is_mapped_mnt(mnt)) > > seq_puts(m, ",idmapped"); > > } > > > > diff --git a/include/linux/fs.h b/include/linux/fs.h > > index 1cb616fc1105..192242476b2b 100644 > > --- a/include/linux/fs.h > > +++ b/include/linux/fs.h > > @@ -2725,6 +2725,20 @@ static inline struct user_namespace *file_mnt_user_ns(struct file *file) > > { > > return mnt_user_ns(file->f_path.mnt); > > } > > + > > +/** > > + * is_mapped_mnt - check whether a mount is mapped > > + * @mnt: the mount to check > > + * > > + * If @mnt has an idmapping attached to it @mnt is mapped. > > + * > > + * Return: true if mount is mapped, false if not. > > + */ > > +static inline bool is_mapped_mnt(const struct vfsmount *mnt) > > +{ > > + return mnt_user_ns(mnt) != &init_user_ns; > > +} > > + > > Maybe is_idmapped_mnt? Fine by me!
diff --git a/fs/cachefiles/bind.c b/fs/cachefiles/bind.c index d463d89f5db8..8130142d89c2 100644 --- a/fs/cachefiles/bind.c +++ b/fs/cachefiles/bind.c @@ -117,7 +117,7 @@ static int cachefiles_daemon_add_cache(struct cachefiles_cache *cache) root = path.dentry; ret = -EINVAL; - if (mnt_user_ns(path.mnt) != &init_user_ns) { + if (is_mapped_mnt(path.mnt)) { pr_warn("File cache on idmapped mounts not supported"); goto error_unsupported; } diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c index d66bbd2df191..331ac3a59515 100644 --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -537,7 +537,7 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags goto out_free; } - if (mnt_user_ns(path.mnt) != &init_user_ns) { + if (is_mapped_mnt(path.mnt)) { rc = -EINVAL; printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n"); goto out_free; diff --git a/fs/namespace.c b/fs/namespace.c index 659a8f39c61a..7d7b80b375a4 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3936,7 +3936,7 @@ static int can_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt) * mapping. It makes things simpler and callers can just create * another bind-mount they can idmap if they want to. */ - if (mnt_user_ns(m) != &init_user_ns) + if (is_mapped_mnt(m)) return -EPERM; /* The underlying filesystem doesn't support idmapped mounts yet. */ diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c index 9421dae22737..292bde9e1eb3 100644 --- a/fs/nfsd/export.c +++ b/fs/nfsd/export.c @@ -427,7 +427,7 @@ static int check_export(struct path *path, int *flags, unsigned char *uuid) return -EINVAL; } - if (mnt_user_ns(path->mnt) != &init_user_ns) { + if (is_mapped_mnt(path->mnt)) { dprintk("exp_export: export of idmapped mounts not yet supported.\n"); return -EINVAL; } diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 265181c110ae..113575fc6155 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -873,7 +873,7 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path) pr_err("filesystem on '%s' not supported\n", name); goto out_put; } - if (mnt_user_ns(path->mnt) != &init_user_ns) { + if (is_mapped_mnt(path->mnt)) { pr_err("idmapped layers are currently not supported\n"); goto out_put; } diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c index 392ef5162655..788c687bb052 100644 --- a/fs/proc_namespace.c +++ b/fs/proc_namespace.c @@ -80,7 +80,7 @@ static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) seq_puts(m, fs_infop->str); } - if (mnt_user_ns(mnt) != &init_user_ns) + if (is_mapped_mnt(mnt)) seq_puts(m, ",idmapped"); } diff --git a/include/linux/fs.h b/include/linux/fs.h index 1cb616fc1105..192242476b2b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2725,6 +2725,20 @@ static inline struct user_namespace *file_mnt_user_ns(struct file *file) { return mnt_user_ns(file->f_path.mnt); } + +/** + * is_mapped_mnt - check whether a mount is mapped + * @mnt: the mount to check + * + * If @mnt has an idmapping attached to it @mnt is mapped. + * + * Return: true if mount is mapped, false if not. + */ +static inline bool is_mapped_mnt(const struct vfsmount *mnt) +{ + return mnt_user_ns(mnt) != &init_user_ns; +} + extern long vfs_truncate(const struct path *, loff_t); int do_truncate(struct user_namespace *, struct dentry *, loff_t start, unsigned int time_attrs, struct file *filp);