Add GET and SET attributes ioctls to enable attribute modification. We already do this in FAT and a few userspace utils made for it would benefit from this also working on exFAT, namely fatattr. Signed-off-by: Jan Cincera <hcincera@xxxxxxxxx> --- Changes in v2: - Removed irrelevant comments. - Now masking reserved fields. fs/exfat/exfat_fs.h | 6 +++ fs/exfat/file.c | 93 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 99 insertions(+) diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index 729ada9e26e8..ebe8c4b928f4 100644 --- a/fs/exfat/exfat_fs.h +++ b/fs/exfat/exfat_fs.h @@ -149,6 +149,12 @@ enum { #define DIR_CACHE_SIZE \ (DIV_ROUND_UP(EXFAT_DEN_TO_B(ES_MAX_ENTRY_NUM), SECTOR_SIZE) + 1) +/* + * attribute ioctls, same as their FAT equivalents. + */ +#define EXFAT_IOCTL_GET_ATTRIBUTES _IOR('r', 0x10, __u32) +#define EXFAT_IOCTL_SET_ATTRIBUTES _IOW('r', 0x11, __u32) + struct exfat_dentry_namebuf { char *lfn; int lfnbuf_len; /* usually MAX_UNINAME_BUF_SIZE */ diff --git a/fs/exfat/file.c b/fs/exfat/file.c index 3cbd270e0cba..b31ce0868ddd 100644 --- a/fs/exfat/file.c +++ b/fs/exfat/file.c @@ -8,6 +8,8 @@ #include <linux/cred.h> #include <linux/buffer_head.h> #include <linux/blkdev.h> +#include <linux/fsnotify.h> +#include <linux/security.h> #include "exfat_raw.h" #include "exfat_fs.h" @@ -316,6 +318,92 @@ int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry, return error; } +/* + * modified ioctls from fat/file.c by Welmer Almesberger + */ +static int exfat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr) +{ + u32 attr; + + inode_lock_shared(inode); + attr = exfat_make_attr(inode); + inode_unlock_shared(inode); + + return put_user(attr, user_attr); +} + +static int exfat_ioctl_set_attributes(struct file *file, u32 __user *user_attr) +{ + struct inode *inode = file_inode(file); + struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb); + int is_dir = S_ISDIR(inode->i_mode); + u32 attr, oldattr; + struct iattr ia; + int err; + + err = get_user(attr, user_attr); + if (err) + goto out; + + err = mnt_want_write_file(file); + if (err) + goto out; + inode_lock(inode); + + oldattr = exfat_make_attr(inode); + + /* + * Mask attributes so we don't set reserved fields. + */ + attr &= (ATTR_READONLY | ATTR_HIDDEN | ATTR_SYSTEM | ATTR_ARCHIVE); + attr |= (is_dir ? ATTR_SUBDIR : 0); + + /* Equivalent to a chmod() */ + ia.ia_valid = ATTR_MODE | ATTR_CTIME; + ia.ia_ctime = current_time(inode); + if (is_dir) + ia.ia_mode = exfat_make_mode(sbi, attr, 0777); + else + ia.ia_mode = exfat_make_mode(sbi, attr, 0666 | (inode->i_mode & 0111)); + + /* The root directory has no attributes */ + if (inode->i_ino == EXFAT_ROOT_INO && attr != ATTR_SUBDIR) { + err = -EINVAL; + goto out_unlock_inode; + } + + if (((attr | oldattr) & ATTR_SYSTEM) && + !capable(CAP_LINUX_IMMUTABLE)) { + err = -EPERM; + goto out_unlock_inode; + } + + /* + * The security check is questionable... We single + * out the RO attribute for checking by the security + * module, just because it maps to a file mode. + */ + err = security_inode_setattr(file_mnt_idmap(file), + file->f_path.dentry, &ia); + if (err) + goto out_unlock_inode; + + /* This MUST be done before doing anything irreversible... */ + err = exfat_setattr(file_mnt_idmap(file), file->f_path.dentry, &ia); + if (err) + goto out_unlock_inode; + + fsnotify_change(file->f_path.dentry, ia.ia_valid); + + exfat_save_attr(inode, attr); + mark_inode_dirty(inode); +out_unlock_inode: + inode_unlock(inode); + mnt_drop_write_file(file); +out: + return err; +} + static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg) { struct fstrim_range range; @@ -346,8 +434,13 @@ static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg) long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = file_inode(filp); + u32 __user *user_attr = (u32 __user *)arg; switch (cmd) { + case EXFAT_IOCTL_GET_ATTRIBUTES: + return exfat_ioctl_get_attributes(inode, user_attr); + case EXFAT_IOCTL_SET_ATTRIBUTES: + return exfat_ioctl_set_attributes(filp, user_attr); case FITRIM: return exfat_ioctl_fitrim(inode, arg); default: -- 2.40.1