fs: split fileattr related helpers into separate file

This patch moves function related to file extended attributes
manipulations to separate file. Refactoring only.

Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
Link: https://lore.kernel.org/20250630-xattrat-syscall-v6-1-c4e3bc35227b@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Andrey Albershteyn 2025-06-30 18:20:11 +02:00 committed by Christian Brauner
parent 19272b37aa
commit 2f952c9e8f
No known key found for this signature in database
GPG key ID: 91C61BC06578DCA2
4 changed files with 325 additions and 310 deletions

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@ -15,7 +15,8 @@ obj-y := open.o read_write.o file_table.o super.o \
pnode.o splice.o sync.o utimes.o d_path.o \ pnode.o splice.o sync.o utimes.o d_path.o \
stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \ stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \
fs_types.o fs_context.o fs_parser.o fsopen.o init.o \ fs_types.o fs_context.o fs_parser.o fsopen.o init.o \
kernel_read_file.o mnt_idmapping.o remap_range.o pidfs.o kernel_read_file.o mnt_idmapping.o remap_range.o pidfs.o \
file_attr.o
obj-$(CONFIG_BUFFER_HEAD) += buffer.o mpage.o obj-$(CONFIG_BUFFER_HEAD) += buffer.o mpage.o
obj-$(CONFIG_PROC_FS) += proc_namespace.o obj-$(CONFIG_PROC_FS) += proc_namespace.o

319
fs/file_attr.c Normal file
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@ -0,0 +1,319 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/fscrypt.h>
#include <linux/fileattr.h>
#include <linux/export.h>
/**
* fileattr_fill_xflags - initialize fileattr with xflags
* @fa: fileattr pointer
* @xflags: FS_XFLAG_* flags
*
* Set ->fsx_xflags, ->fsx_valid and ->flags (translated xflags). All
* other fields are zeroed.
*/
void fileattr_fill_xflags(struct fileattr *fa, u32 xflags)
{
memset(fa, 0, sizeof(*fa));
fa->fsx_valid = true;
fa->fsx_xflags = xflags;
if (fa->fsx_xflags & FS_XFLAG_IMMUTABLE)
fa->flags |= FS_IMMUTABLE_FL;
if (fa->fsx_xflags & FS_XFLAG_APPEND)
fa->flags |= FS_APPEND_FL;
if (fa->fsx_xflags & FS_XFLAG_SYNC)
fa->flags |= FS_SYNC_FL;
if (fa->fsx_xflags & FS_XFLAG_NOATIME)
fa->flags |= FS_NOATIME_FL;
if (fa->fsx_xflags & FS_XFLAG_NODUMP)
fa->flags |= FS_NODUMP_FL;
if (fa->fsx_xflags & FS_XFLAG_DAX)
fa->flags |= FS_DAX_FL;
if (fa->fsx_xflags & FS_XFLAG_PROJINHERIT)
fa->flags |= FS_PROJINHERIT_FL;
}
EXPORT_SYMBOL(fileattr_fill_xflags);
/**
* fileattr_fill_flags - initialize fileattr with flags
* @fa: fileattr pointer
* @flags: FS_*_FL flags
*
* Set ->flags, ->flags_valid and ->fsx_xflags (translated flags).
* All other fields are zeroed.
*/
void fileattr_fill_flags(struct fileattr *fa, u32 flags)
{
memset(fa, 0, sizeof(*fa));
fa->flags_valid = true;
fa->flags = flags;
if (fa->flags & FS_SYNC_FL)
fa->fsx_xflags |= FS_XFLAG_SYNC;
if (fa->flags & FS_IMMUTABLE_FL)
fa->fsx_xflags |= FS_XFLAG_IMMUTABLE;
if (fa->flags & FS_APPEND_FL)
fa->fsx_xflags |= FS_XFLAG_APPEND;
if (fa->flags & FS_NODUMP_FL)
fa->fsx_xflags |= FS_XFLAG_NODUMP;
if (fa->flags & FS_NOATIME_FL)
fa->fsx_xflags |= FS_XFLAG_NOATIME;
if (fa->flags & FS_DAX_FL)
fa->fsx_xflags |= FS_XFLAG_DAX;
if (fa->flags & FS_PROJINHERIT_FL)
fa->fsx_xflags |= FS_XFLAG_PROJINHERIT;
}
EXPORT_SYMBOL(fileattr_fill_flags);
/**
* vfs_fileattr_get - retrieve miscellaneous file attributes
* @dentry: the object to retrieve from
* @fa: fileattr pointer
*
* Call i_op->fileattr_get() callback, if exists.
*
* Return: 0 on success, or a negative error on failure.
*/
int vfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
{
struct inode *inode = d_inode(dentry);
if (!inode->i_op->fileattr_get)
return -ENOIOCTLCMD;
return inode->i_op->fileattr_get(dentry, fa);
}
EXPORT_SYMBOL(vfs_fileattr_get);
/**
* copy_fsxattr_to_user - copy fsxattr to userspace.
* @fa: fileattr pointer
* @ufa: fsxattr user pointer
*
* Return: 0 on success, or -EFAULT on failure.
*/
int copy_fsxattr_to_user(const struct fileattr *fa, struct fsxattr __user *ufa)
{
struct fsxattr xfa;
memset(&xfa, 0, sizeof(xfa));
xfa.fsx_xflags = fa->fsx_xflags;
xfa.fsx_extsize = fa->fsx_extsize;
xfa.fsx_nextents = fa->fsx_nextents;
xfa.fsx_projid = fa->fsx_projid;
xfa.fsx_cowextsize = fa->fsx_cowextsize;
if (copy_to_user(ufa, &xfa, sizeof(xfa)))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL(copy_fsxattr_to_user);
static int copy_fsxattr_from_user(struct fileattr *fa,
struct fsxattr __user *ufa)
{
struct fsxattr xfa;
if (copy_from_user(&xfa, ufa, sizeof(xfa)))
return -EFAULT;
fileattr_fill_xflags(fa, xfa.fsx_xflags);
fa->fsx_extsize = xfa.fsx_extsize;
fa->fsx_nextents = xfa.fsx_nextents;
fa->fsx_projid = xfa.fsx_projid;
fa->fsx_cowextsize = xfa.fsx_cowextsize;
return 0;
}
/*
* Generic function to check FS_IOC_FSSETXATTR/FS_IOC_SETFLAGS values and reject
* any invalid configurations.
*
* Note: must be called with inode lock held.
*/
static int fileattr_set_prepare(struct inode *inode,
const struct fileattr *old_ma,
struct fileattr *fa)
{
int err;
/*
* The IMMUTABLE and APPEND_ONLY flags can only be changed by
* the relevant capability.
*/
if ((fa->flags ^ old_ma->flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) &&
!capable(CAP_LINUX_IMMUTABLE))
return -EPERM;
err = fscrypt_prepare_setflags(inode, old_ma->flags, fa->flags);
if (err)
return err;
/*
* Project Quota ID state is only allowed to change from within the init
* namespace. Enforce that restriction only if we are trying to change
* the quota ID state. Everything else is allowed in user namespaces.
*/
if (current_user_ns() != &init_user_ns) {
if (old_ma->fsx_projid != fa->fsx_projid)
return -EINVAL;
if ((old_ma->fsx_xflags ^ fa->fsx_xflags) &
FS_XFLAG_PROJINHERIT)
return -EINVAL;
} else {
/*
* Caller is allowed to change the project ID. If it is being
* changed, make sure that the new value is valid.
*/
if (old_ma->fsx_projid != fa->fsx_projid &&
!projid_valid(make_kprojid(&init_user_ns, fa->fsx_projid)))
return -EINVAL;
}
/* Check extent size hints. */
if ((fa->fsx_xflags & FS_XFLAG_EXTSIZE) && !S_ISREG(inode->i_mode))
return -EINVAL;
if ((fa->fsx_xflags & FS_XFLAG_EXTSZINHERIT) &&
!S_ISDIR(inode->i_mode))
return -EINVAL;
if ((fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) &&
!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
return -EINVAL;
/*
* It is only valid to set the DAX flag on regular files and
* directories on filesystems.
*/
if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
return -EINVAL;
/* Extent size hints of zero turn off the flags. */
if (fa->fsx_extsize == 0)
fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT);
if (fa->fsx_cowextsize == 0)
fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;
return 0;
}
/**
* vfs_fileattr_set - change miscellaneous file attributes
* @idmap: idmap of the mount
* @dentry: the object to change
* @fa: fileattr pointer
*
* After verifying permissions, call i_op->fileattr_set() callback, if
* exists.
*
* Verifying attributes involves retrieving current attributes with
* i_op->fileattr_get(), this also allows initializing attributes that have
* not been set by the caller to current values. Inode lock is held
* thoughout to prevent racing with another instance.
*
* Return: 0 on success, or a negative error on failure.
*/
int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry,
struct fileattr *fa)
{
struct inode *inode = d_inode(dentry);
struct fileattr old_ma = {};
int err;
if (!inode->i_op->fileattr_set)
return -ENOIOCTLCMD;
if (!inode_owner_or_capable(idmap, inode))
return -EPERM;
inode_lock(inode);
err = vfs_fileattr_get(dentry, &old_ma);
if (!err) {
/* initialize missing bits from old_ma */
if (fa->flags_valid) {
fa->fsx_xflags |= old_ma.fsx_xflags & ~FS_XFLAG_COMMON;
fa->fsx_extsize = old_ma.fsx_extsize;
fa->fsx_nextents = old_ma.fsx_nextents;
fa->fsx_projid = old_ma.fsx_projid;
fa->fsx_cowextsize = old_ma.fsx_cowextsize;
} else {
fa->flags |= old_ma.flags & ~FS_COMMON_FL;
}
err = fileattr_set_prepare(inode, &old_ma, fa);
if (!err)
err = inode->i_op->fileattr_set(idmap, dentry, fa);
}
inode_unlock(inode);
return err;
}
EXPORT_SYMBOL(vfs_fileattr_set);
int ioctl_getflags(struct file *file, unsigned int __user *argp)
{
struct fileattr fa = { .flags_valid = true }; /* hint only */
int err;
err = vfs_fileattr_get(file->f_path.dentry, &fa);
if (!err)
err = put_user(fa.flags, argp);
return err;
}
EXPORT_SYMBOL(ioctl_getflags);
int ioctl_setflags(struct file *file, unsigned int __user *argp)
{
struct mnt_idmap *idmap = file_mnt_idmap(file);
struct dentry *dentry = file->f_path.dentry;
struct fileattr fa;
unsigned int flags;
int err;
err = get_user(flags, argp);
if (!err) {
err = mnt_want_write_file(file);
if (!err) {
fileattr_fill_flags(&fa, flags);
err = vfs_fileattr_set(idmap, dentry, &fa);
mnt_drop_write_file(file);
}
}
return err;
}
EXPORT_SYMBOL(ioctl_setflags);
int ioctl_fsgetxattr(struct file *file, void __user *argp)
{
struct fileattr fa = { .fsx_valid = true }; /* hint only */
int err;
err = vfs_fileattr_get(file->f_path.dentry, &fa);
if (!err)
err = copy_fsxattr_to_user(&fa, argp);
return err;
}
EXPORT_SYMBOL(ioctl_fsgetxattr);
int ioctl_fssetxattr(struct file *file, void __user *argp)
{
struct mnt_idmap *idmap = file_mnt_idmap(file);
struct dentry *dentry = file->f_path.dentry;
struct fileattr fa;
int err;
err = copy_fsxattr_from_user(&fa, argp);
if (!err) {
err = mnt_want_write_file(file);
if (!err) {
err = vfs_fileattr_set(idmap, dentry, &fa);
mnt_drop_write_file(file);
}
}
return err;
}
EXPORT_SYMBOL(ioctl_fssetxattr);

View file

@ -453,315 +453,6 @@ out:
return ret; return ret;
} }
/**
* fileattr_fill_xflags - initialize fileattr with xflags
* @fa: fileattr pointer
* @xflags: FS_XFLAG_* flags
*
* Set ->fsx_xflags, ->fsx_valid and ->flags (translated xflags). All
* other fields are zeroed.
*/
void fileattr_fill_xflags(struct fileattr *fa, u32 xflags)
{
memset(fa, 0, sizeof(*fa));
fa->fsx_valid = true;
fa->fsx_xflags = xflags;
if (fa->fsx_xflags & FS_XFLAG_IMMUTABLE)
fa->flags |= FS_IMMUTABLE_FL;
if (fa->fsx_xflags & FS_XFLAG_APPEND)
fa->flags |= FS_APPEND_FL;
if (fa->fsx_xflags & FS_XFLAG_SYNC)
fa->flags |= FS_SYNC_FL;
if (fa->fsx_xflags & FS_XFLAG_NOATIME)
fa->flags |= FS_NOATIME_FL;
if (fa->fsx_xflags & FS_XFLAG_NODUMP)
fa->flags |= FS_NODUMP_FL;
if (fa->fsx_xflags & FS_XFLAG_DAX)
fa->flags |= FS_DAX_FL;
if (fa->fsx_xflags & FS_XFLAG_PROJINHERIT)
fa->flags |= FS_PROJINHERIT_FL;
}
EXPORT_SYMBOL(fileattr_fill_xflags);
/**
* fileattr_fill_flags - initialize fileattr with flags
* @fa: fileattr pointer
* @flags: FS_*_FL flags
*
* Set ->flags, ->flags_valid and ->fsx_xflags (translated flags).
* All other fields are zeroed.
*/
void fileattr_fill_flags(struct fileattr *fa, u32 flags)
{
memset(fa, 0, sizeof(*fa));
fa->flags_valid = true;
fa->flags = flags;
if (fa->flags & FS_SYNC_FL)
fa->fsx_xflags |= FS_XFLAG_SYNC;
if (fa->flags & FS_IMMUTABLE_FL)
fa->fsx_xflags |= FS_XFLAG_IMMUTABLE;
if (fa->flags & FS_APPEND_FL)
fa->fsx_xflags |= FS_XFLAG_APPEND;
if (fa->flags & FS_NODUMP_FL)
fa->fsx_xflags |= FS_XFLAG_NODUMP;
if (fa->flags & FS_NOATIME_FL)
fa->fsx_xflags |= FS_XFLAG_NOATIME;
if (fa->flags & FS_DAX_FL)
fa->fsx_xflags |= FS_XFLAG_DAX;
if (fa->flags & FS_PROJINHERIT_FL)
fa->fsx_xflags |= FS_XFLAG_PROJINHERIT;
}
EXPORT_SYMBOL(fileattr_fill_flags);
/**
* vfs_fileattr_get - retrieve miscellaneous file attributes
* @dentry: the object to retrieve from
* @fa: fileattr pointer
*
* Call i_op->fileattr_get() callback, if exists.
*
* Return: 0 on success, or a negative error on failure.
*/
int vfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
{
struct inode *inode = d_inode(dentry);
if (!inode->i_op->fileattr_get)
return -ENOIOCTLCMD;
return inode->i_op->fileattr_get(dentry, fa);
}
EXPORT_SYMBOL(vfs_fileattr_get);
/**
* copy_fsxattr_to_user - copy fsxattr to userspace.
* @fa: fileattr pointer
* @ufa: fsxattr user pointer
*
* Return: 0 on success, or -EFAULT on failure.
*/
int copy_fsxattr_to_user(const struct fileattr *fa, struct fsxattr __user *ufa)
{
struct fsxattr xfa;
memset(&xfa, 0, sizeof(xfa));
xfa.fsx_xflags = fa->fsx_xflags;
xfa.fsx_extsize = fa->fsx_extsize;
xfa.fsx_nextents = fa->fsx_nextents;
xfa.fsx_projid = fa->fsx_projid;
xfa.fsx_cowextsize = fa->fsx_cowextsize;
if (copy_to_user(ufa, &xfa, sizeof(xfa)))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL(copy_fsxattr_to_user);
static int copy_fsxattr_from_user(struct fileattr *fa,
struct fsxattr __user *ufa)
{
struct fsxattr xfa;
if (copy_from_user(&xfa, ufa, sizeof(xfa)))
return -EFAULT;
fileattr_fill_xflags(fa, xfa.fsx_xflags);
fa->fsx_extsize = xfa.fsx_extsize;
fa->fsx_nextents = xfa.fsx_nextents;
fa->fsx_projid = xfa.fsx_projid;
fa->fsx_cowextsize = xfa.fsx_cowextsize;
return 0;
}
/*
* Generic function to check FS_IOC_FSSETXATTR/FS_IOC_SETFLAGS values and reject
* any invalid configurations.
*
* Note: must be called with inode lock held.
*/
static int fileattr_set_prepare(struct inode *inode,
const struct fileattr *old_ma,
struct fileattr *fa)
{
int err;
/*
* The IMMUTABLE and APPEND_ONLY flags can only be changed by
* the relevant capability.
*/
if ((fa->flags ^ old_ma->flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) &&
!capable(CAP_LINUX_IMMUTABLE))
return -EPERM;
err = fscrypt_prepare_setflags(inode, old_ma->flags, fa->flags);
if (err)
return err;
/*
* Project Quota ID state is only allowed to change from within the init
* namespace. Enforce that restriction only if we are trying to change
* the quota ID state. Everything else is allowed in user namespaces.
*/
if (current_user_ns() != &init_user_ns) {
if (old_ma->fsx_projid != fa->fsx_projid)
return -EINVAL;
if ((old_ma->fsx_xflags ^ fa->fsx_xflags) &
FS_XFLAG_PROJINHERIT)
return -EINVAL;
} else {
/*
* Caller is allowed to change the project ID. If it is being
* changed, make sure that the new value is valid.
*/
if (old_ma->fsx_projid != fa->fsx_projid &&
!projid_valid(make_kprojid(&init_user_ns, fa->fsx_projid)))
return -EINVAL;
}
/* Check extent size hints. */
if ((fa->fsx_xflags & FS_XFLAG_EXTSIZE) && !S_ISREG(inode->i_mode))
return -EINVAL;
if ((fa->fsx_xflags & FS_XFLAG_EXTSZINHERIT) &&
!S_ISDIR(inode->i_mode))
return -EINVAL;
if ((fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) &&
!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
return -EINVAL;
/*
* It is only valid to set the DAX flag on regular files and
* directories on filesystems.
*/
if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
return -EINVAL;
/* Extent size hints of zero turn off the flags. */
if (fa->fsx_extsize == 0)
fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT);
if (fa->fsx_cowextsize == 0)
fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;
return 0;
}
/**
* vfs_fileattr_set - change miscellaneous file attributes
* @idmap: idmap of the mount
* @dentry: the object to change
* @fa: fileattr pointer
*
* After verifying permissions, call i_op->fileattr_set() callback, if
* exists.
*
* Verifying attributes involves retrieving current attributes with
* i_op->fileattr_get(), this also allows initializing attributes that have
* not been set by the caller to current values. Inode lock is held
* thoughout to prevent racing with another instance.
*
* Return: 0 on success, or a negative error on failure.
*/
int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry,
struct fileattr *fa)
{
struct inode *inode = d_inode(dentry);
struct fileattr old_ma = {};
int err;
if (!inode->i_op->fileattr_set)
return -ENOIOCTLCMD;
if (!inode_owner_or_capable(idmap, inode))
return -EPERM;
inode_lock(inode);
err = vfs_fileattr_get(dentry, &old_ma);
if (!err) {
/* initialize missing bits from old_ma */
if (fa->flags_valid) {
fa->fsx_xflags |= old_ma.fsx_xflags & ~FS_XFLAG_COMMON;
fa->fsx_extsize = old_ma.fsx_extsize;
fa->fsx_nextents = old_ma.fsx_nextents;
fa->fsx_projid = old_ma.fsx_projid;
fa->fsx_cowextsize = old_ma.fsx_cowextsize;
} else {
fa->flags |= old_ma.flags & ~FS_COMMON_FL;
}
err = fileattr_set_prepare(inode, &old_ma, fa);
if (!err)
err = inode->i_op->fileattr_set(idmap, dentry, fa);
}
inode_unlock(inode);
return err;
}
EXPORT_SYMBOL(vfs_fileattr_set);
static int ioctl_getflags(struct file *file, unsigned int __user *argp)
{
struct fileattr fa = { .flags_valid = true }; /* hint only */
int err;
err = vfs_fileattr_get(file->f_path.dentry, &fa);
if (!err)
err = put_user(fa.flags, argp);
return err;
}
static int ioctl_setflags(struct file *file, unsigned int __user *argp)
{
struct mnt_idmap *idmap = file_mnt_idmap(file);
struct dentry *dentry = file->f_path.dentry;
struct fileattr fa;
unsigned int flags;
int err;
err = get_user(flags, argp);
if (!err) {
err = mnt_want_write_file(file);
if (!err) {
fileattr_fill_flags(&fa, flags);
err = vfs_fileattr_set(idmap, dentry, &fa);
mnt_drop_write_file(file);
}
}
return err;
}
static int ioctl_fsgetxattr(struct file *file, void __user *argp)
{
struct fileattr fa = { .fsx_valid = true }; /* hint only */
int err;
err = vfs_fileattr_get(file->f_path.dentry, &fa);
if (!err)
err = copy_fsxattr_to_user(&fa, argp);
return err;
}
static int ioctl_fssetxattr(struct file *file, void __user *argp)
{
struct mnt_idmap *idmap = file_mnt_idmap(file);
struct dentry *dentry = file->f_path.dentry;
struct fileattr fa;
int err;
err = copy_fsxattr_from_user(&fa, argp);
if (!err) {
err = mnt_want_write_file(file);
if (!err) {
err = vfs_fileattr_set(idmap, dentry, &fa);
mnt_drop_write_file(file);
}
}
return err;
}
static int ioctl_getfsuuid(struct file *file, void __user *argp) static int ioctl_getfsuuid(struct file *file, void __user *argp)
{ {
struct super_block *sb = file_inode(file)->i_sb; struct super_block *sb = file_inode(file)->i_sb;

View file

@ -55,5 +55,9 @@ static inline bool fileattr_has_fsx(const struct fileattr *fa)
int vfs_fileattr_get(struct dentry *dentry, struct fileattr *fa); int vfs_fileattr_get(struct dentry *dentry, struct fileattr *fa);
int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry, int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry,
struct fileattr *fa); struct fileattr *fa);
int ioctl_getflags(struct file *file, unsigned int __user *argp);
int ioctl_setflags(struct file *file, unsigned int __user *argp);
int ioctl_fsgetxattr(struct file *file, void __user *argp);
int ioctl_fssetxattr(struct file *file, void __user *argp);
#endif /* _LINUX_FILEATTR_H */ #endif /* _LINUX_FILEATTR_H */