| Message ID | 20250210-work-overlayfs-v2-1-ed2a949b674b@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | ovl: allow O_PATH file descriptor when specifying layers | expand |
On Mon, Feb 10, 2025 at 1:39 PM Christian Brauner <brauner@kernel.org> wrote: > > Let FSCONFIG_SET_FD handle O_PATH file descriptors. This is particularly > useful in the context of overlayfs where layers can be specified via > file descriptors instead of paths. But userspace must currently use > non-O_PATH file desriptors which is often pointless especially if > the file descriptors have been created via open_tree(OPEN_TREE_CLONE). > > Fixes: a08557d19ef41 ("ovl: specify layers via file descriptors") > Signed-off-by: Christian Brauner <brauner@kernel.org> > --- > fs/autofs/autofs_i.h | 2 ++ > fs/fsopen.c | 2 +- > 2 files changed, 3 insertions(+), 1 deletion(-) > > diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h > index 77c7991d89aa..23cea74f9933 100644 > --- a/fs/autofs/autofs_i.h > +++ b/fs/autofs/autofs_i.h > @@ -218,6 +218,8 @@ void autofs_clean_ino(struct autofs_info *); > > static inline int autofs_check_pipe(struct file *pipe) > { > + if (pipe->f_mode & FMODE_PATH) > + return -EINVAL; > if (!(pipe->f_mode & FMODE_CAN_WRITE)) > return -EINVAL; I thought you said the above check is redundant due to the lower check. In any case feel free to add Reviewed-by: Amir Goldstein <amir73il@gmail.com> > if (!S_ISFIFO(file_inode(pipe)->i_mode)) > diff --git a/fs/fsopen.c b/fs/fsopen.c > index 094a7f510edf..1aaf4cb2afb2 100644 > --- a/fs/fsopen.c > +++ b/fs/fsopen.c > @@ -453,7 +453,7 @@ SYSCALL_DEFINE5(fsconfig, > case FSCONFIG_SET_FD: > param.type = fs_value_is_file; > ret = -EBADF; > - param.file = fget(aux); > + param.file = fget_raw(aux); > if (!param.file) > goto out_key; > param.dirfd = aux; > > -- > 2.47.2 >
On Mon, Feb 10, 2025 at 02:26:56PM +0100, Amir Goldstein wrote: > On Mon, Feb 10, 2025 at 1:39 PM Christian Brauner <brauner@kernel.org> wrote: > > > > Let FSCONFIG_SET_FD handle O_PATH file descriptors. This is particularly > > useful in the context of overlayfs where layers can be specified via > > file descriptors instead of paths. But userspace must currently use > > non-O_PATH file desriptors which is often pointless especially if > > the file descriptors have been created via open_tree(OPEN_TREE_CLONE). > > > > Fixes: a08557d19ef41 ("ovl: specify layers via file descriptors") > > Signed-off-by: Christian Brauner <brauner@kernel.org> > > --- > > fs/autofs/autofs_i.h | 2 ++ > > fs/fsopen.c | 2 +- > > 2 files changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h > > index 77c7991d89aa..23cea74f9933 100644 > > --- a/fs/autofs/autofs_i.h > > +++ b/fs/autofs/autofs_i.h > > @@ -218,6 +218,8 @@ void autofs_clean_ino(struct autofs_info *); > > > > static inline int autofs_check_pipe(struct file *pipe) > > { > > + if (pipe->f_mode & FMODE_PATH) > > + return -EINVAL; > > if (!(pipe->f_mode & FMODE_CAN_WRITE)) > > return -EINVAL; > > I thought you said the above check is redundant due to the lower check. It is but that's only obvious to people quite familiar with VFS code. So I like the explicitly check here. > > In any case feel free to add > > Reviewed-by: Amir Goldstein <amir73il@gmail.com> > > > if (!S_ISFIFO(file_inode(pipe)->i_mode)) > > diff --git a/fs/fsopen.c b/fs/fsopen.c > > index 094a7f510edf..1aaf4cb2afb2 100644 > > --- a/fs/fsopen.c > > +++ b/fs/fsopen.c > > @@ -453,7 +453,7 @@ SYSCALL_DEFINE5(fsconfig, > > case FSCONFIG_SET_FD: > > param.type = fs_value_is_file; > > ret = -EBADF; > > - param.file = fget(aux); > > + param.file = fget_raw(aux); > > if (!param.file) > > goto out_key; > > param.dirfd = aux; > > > > -- > > 2.47.2 > >
diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h index 77c7991d89aa..23cea74f9933 100644 --- a/fs/autofs/autofs_i.h +++ b/fs/autofs/autofs_i.h @@ -218,6 +218,8 @@ void autofs_clean_ino(struct autofs_info *); static inline int autofs_check_pipe(struct file *pipe) { + if (pipe->f_mode & FMODE_PATH) + return -EINVAL; if (!(pipe->f_mode & FMODE_CAN_WRITE)) return -EINVAL; if (!S_ISFIFO(file_inode(pipe)->i_mode)) diff --git a/fs/fsopen.c b/fs/fsopen.c index 094a7f510edf..1aaf4cb2afb2 100644 --- a/fs/fsopen.c +++ b/fs/fsopen.c @@ -453,7 +453,7 @@ SYSCALL_DEFINE5(fsconfig, case FSCONFIG_SET_FD: param.type = fs_value_is_file; ret = -EBADF; - param.file = fget(aux); + param.file = fget_raw(aux); if (!param.file) goto out_key; param.dirfd = aux;
Let FSCONFIG_SET_FD handle O_PATH file descriptors. This is particularly useful in the context of overlayfs where layers can be specified via file descriptors instead of paths. But userspace must currently use non-O_PATH file desriptors which is often pointless especially if the file descriptors have been created via open_tree(OPEN_TREE_CLONE). Fixes: a08557d19ef41 ("ovl: specify layers via file descriptors") Signed-off-by: Christian Brauner <brauner@kernel.org> --- fs/autofs/autofs_i.h | 2 ++ fs/fsopen.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-)