diff options
| -rw-r--r-- | Documentation/filesystems/locking.rst | 11 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.rst | 15 | ||||
| -rw-r--r-- | fs/ioctl.c | 325 | ||||
| -rw-r--r-- | include/linux/fileattr.h | 59 | ||||
| -rw-r--r-- | include/linux/fs.h | 4 |
5 files changed, 411 insertions, 3 deletions
diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index b7dcc86c92a4..729ce492b662 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -80,13 +80,16 @@ prototypes:: struct file *, unsigned open_flag, umode_t create_mode); int (*tmpfile) (struct inode *, struct dentry *, umode_t); + int (*fileattr_set)(struct user_namespace *mnt_userns, + struct dentry *dentry, struct fileattr *fa); + int (*fileattr_get)(struct dentry *dentry, struct fileattr *fa); locking rules: all may block -============ ============================================= +============= ============================================= ops i_rwsem(inode) -============ ============================================= +============= ============================================= lookup: shared create: exclusive link: exclusive (both) @@ -107,7 +110,9 @@ fiemap: no update_time: no atomic_open: shared (exclusive if O_CREAT is set in open flags) tmpfile: no -============ ============================================= +fileattr_get: no or exclusive +fileattr_set: exclusive +============= ============================================= Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_rwsem diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index 2049bbf5e388..14c31eced416 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -441,6 +441,9 @@ As of kernel 2.6.22, the following members are defined: unsigned open_flag, umode_t create_mode); int (*tmpfile) (struct user_namespace *, struct inode *, struct dentry *, umode_t); int (*set_acl)(struct user_namespace *, struct inode *, struct posix_acl *, int); + int (*fileattr_set)(struct user_namespace *mnt_userns, + struct dentry *dentry, struct fileattr *fa); + int (*fileattr_get)(struct dentry *dentry, struct fileattr *fa); }; Again, all methods are called without any locks being held, unless @@ -588,6 +591,18 @@ otherwise noted. atomically creating, opening and unlinking a file in given directory. +``fileattr_get`` + called on ioctl(FS_IOC_GETFLAGS) and ioctl(FS_IOC_FSGETXATTR) to + retrieve miscellaneous file flags and attributes. Also called + before the relevant SET operation to check what is being changed + (in this case with i_rwsem locked exclusive). If unset, then + fall back to f_op->ioctl(). + +``fileattr_set`` + called on ioctl(FS_IOC_SETFLAGS) and ioctl(FS_IOC_FSSETXATTR) to + change miscellaneous file flags and attributes. Callers hold + i_rwsem exclusive. If unset, then fall back to f_op->ioctl(). + The Address Space Object ======================== diff --git a/fs/ioctl.c b/fs/ioctl.c index 4e6cc0a7d69c..1e2204fa9963 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -19,6 +19,9 @@ #include <linux/falloc.h> #include <linux/sched/signal.h> #include <linux/fiemap.h> +#include <linux/mount.h> +#include <linux/fscrypt.h> +#include <linux/fileattr.h> #include "internal.h" @@ -657,6 +660,307 @@ out: 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; + } + + /* 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 + * @mnt_userns: user namespace 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 user_namespace *mnt_userns, 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(mnt_userns, 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(mnt_userns, 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 user_namespace *mnt_userns = file_mnt_user_ns(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(mnt_userns, 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 user_namespace *mnt_userns = file_mnt_user_ns(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(mnt_userns, dentry, &fa); + mnt_drop_write_file(file); + } + } + return err; +} + /* * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d. * It's just a simple helper for sys_ioctl and compat_sys_ioctl. @@ -727,6 +1031,18 @@ static int do_vfs_ioctl(struct file *filp, unsigned int fd, return put_user(i_size_read(inode) - filp->f_pos, (int __user *)argp); + case FS_IOC_GETFLAGS: + return ioctl_getflags(filp, argp); + + case FS_IOC_SETFLAGS: + return ioctl_setflags(filp, argp); + + case FS_IOC_FSGETXATTR: + return ioctl_fsgetxattr(filp, argp); + + case FS_IOC_FSSETXATTR: + return ioctl_fssetxattr(filp, argp); + default: if (S_ISREG(inode->i_mode)) return file_ioctl(filp, cmd, argp); @@ -828,6 +1144,15 @@ COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, #endif /* + * These access 32-bit values anyway so no further handling is + * necessary. + */ + case FS_IOC32_GETFLAGS: + case FS_IOC32_SETFLAGS: + cmd = (cmd == FS_IOC32_GETFLAGS) ? + FS_IOC_GETFLAGS : FS_IOC_SETFLAGS; + fallthrough; + /* * everything else in do_vfs_ioctl() takes either a compatible * pointer argument or no argument -- call it with a modified * argument. diff --git a/include/linux/fileattr.h b/include/linux/fileattr.h new file mode 100644 index 000000000000..9e37e063ac69 --- /dev/null +++ b/include/linux/fileattr.h @@ -0,0 +1,59 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _LINUX_FILEATTR_H +#define _LINUX_FILEATTR_H + +/* Flags shared betwen flags/xflags */ +#define FS_COMMON_FL \ + (FS_SYNC_FL | FS_IMMUTABLE_FL | FS_APPEND_FL | \ + FS_NODUMP_FL | FS_NOATIME_FL | FS_DAX_FL | \ + FS_PROJINHERIT_FL) + +#define FS_XFLAG_COMMON \ + (FS_XFLAG_SYNC | FS_XFLAG_IMMUTABLE | FS_XFLAG_APPEND | \ + FS_XFLAG_NODUMP | FS_XFLAG_NOATIME | FS_XFLAG_DAX | \ + FS_XFLAG_PROJINHERIT) + +/* + * Merged interface for miscellaneous file attributes. 'flags' originates from + * ext* and 'fsx_flags' from xfs. There's some overlap between the two, which + * is handled by the VFS helpers, so filesystems are free to implement just one + * or both of these sub-interfaces. + */ +struct fileattr { + u32 flags; /* flags (FS_IOC_GETFLAGS/FS_IOC_SETFLAGS) */ + /* struct fsxattr: */ + u32 fsx_xflags; /* xflags field value (get/set) */ + u32 fsx_extsize; /* extsize field value (get/set)*/ + u32 fsx_nextents; /* nextents field value (get) */ + u32 fsx_projid; /* project identifier (get/set) */ + u32 fsx_cowextsize; /* CoW extsize field value (get/set)*/ + /* selectors: */ + bool flags_valid:1; + bool fsx_valid:1; +}; + +int copy_fsxattr_to_user(const struct fileattr *fa, struct fsxattr __user *ufa); + +void fileattr_fill_xflags(struct fileattr *fa, u32 xflags); +void fileattr_fill_flags(struct fileattr *fa, u32 flags); + +/** + * fileattr_has_fsx - check for extended flags/attributes + * @fa: fileattr pointer + * + * Return: true if any attributes are present that are not represented in + * ->flags. + */ +static inline bool fileattr_has_fsx(const struct fileattr *fa) +{ + return fa->fsx_valid && + ((fa->fsx_xflags & ~FS_XFLAG_COMMON) || fa->fsx_extsize != 0 || + fa->fsx_projid != 0 || fa->fsx_cowextsize != 0); +} + +int vfs_fileattr_get(struct dentry *dentry, struct fileattr *fa); +int vfs_fileattr_set(struct user_namespace *mnt_userns, struct dentry *dentry, + struct fileattr *fa); + +#endif /* _LINUX_FILEATTR_H */ diff --git a/include/linux/fs.h b/include/linux/fs.h index ec8f3ddf4a6a..156b78f42a28 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -70,6 +70,7 @@ struct fsverity_info; struct fsverity_operations; struct fs_context; struct fs_parameter_spec; +struct fileattr; extern void __init inode_init(void); extern void __init inode_init_early(void); @@ -1963,6 +1964,9 @@ struct inode_operations { struct dentry *, umode_t); int (*set_acl)(struct user_namespace *, struct inode *, struct posix_acl *, int); + int (*fileattr_set)(struct user_namespace *mnt_userns, + struct dentry *dentry, struct fileattr *fa); + int (*fileattr_get)(struct dentry *dentry, struct fileattr *fa); } ____cacheline_aligned; static inline ssize_t call_read_iter(struct file *file, struct kiocb *kio, |