exfat: add ioctls for accessing attributes

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@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

fs/exfat/dir.c

@@ -287,7 +287,7 @@ static int exfat_iterate(struct file *file, struct dir_context *ctx)
 
 	mutex_unlock(&EXFAT_SB(sb)->s_lock);
 	if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
-			(de.attr & ATTR_SUBDIR) ? DT_DIR : DT_REG))
+			(de.attr & EXFAT_ATTR_SUBDIR) ? DT_DIR : DT_REG))
 		goto out;
 	ctx->pos = cpos;
 	goto get_new;
@@ -359,7 +359,7 @@ unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
 		if (ep->type == EXFAT_VOLUME)
 			return TYPE_VOLUME;
 		if (ep->type == EXFAT_FILE) {
-			if (le16_to_cpu(ep->dentry.file.attr) & ATTR_SUBDIR)
+			if (le16_to_cpu(ep->dentry.file.attr) & EXFAT_ATTR_SUBDIR)
 				return TYPE_DIR;
 			return TYPE_FILE;
 		}
@@ -410,10 +410,10 @@ static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
 		ep->type = EXFAT_VOLUME;
 	} else if (type == TYPE_DIR) {
 		ep->type = EXFAT_FILE;
-		ep->dentry.file.attr = cpu_to_le16(ATTR_SUBDIR);
+		ep->dentry.file.attr = cpu_to_le16(EXFAT_ATTR_SUBDIR);
 	} else if (type == TYPE_FILE) {
 		ep->type = EXFAT_FILE;
-		ep->dentry.file.attr = cpu_to_le16(ATTR_ARCHIVE);
+		ep->dentry.file.attr = cpu_to_le16(EXFAT_ATTR_ARCHIVE);
 	}
 }
 

fs/exfat/exfat_fs.h

@@ -357,10 +357,10 @@ static inline int exfat_mode_can_hold_ro(struct inode *inode)
 static inline mode_t exfat_make_mode(struct exfat_sb_info *sbi,
 		unsigned short attr, mode_t mode)
 {
-	if ((attr & ATTR_READONLY) && !(attr & ATTR_SUBDIR))
+	if ((attr & EXFAT_ATTR_READONLY) && !(attr & EXFAT_ATTR_SUBDIR))
 		mode &= ~0222;
 
-	if (attr & ATTR_SUBDIR)
+	if (attr & EXFAT_ATTR_SUBDIR)
 		return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
 
 	return (mode & ~sbi->options.fs_fmask) | S_IFREG;
@@ -372,18 +372,18 @@ static inline unsigned short exfat_make_attr(struct inode *inode)
 	unsigned short attr = EXFAT_I(inode)->attr;
 
 	if (S_ISDIR(inode->i_mode))
-		attr |= ATTR_SUBDIR;
+		attr |= EXFAT_ATTR_SUBDIR;
 	if (exfat_mode_can_hold_ro(inode) && !(inode->i_mode & 0222))
-		attr |= ATTR_READONLY;
+		attr |= EXFAT_ATTR_READONLY;
 	return attr;
 }
 
 static inline void exfat_save_attr(struct inode *inode, unsigned short attr)
 {
 	if (exfat_mode_can_hold_ro(inode))
-		EXFAT_I(inode)->attr = attr & (ATTR_RWMASK | ATTR_READONLY);
+		EXFAT_I(inode)->attr = attr & (EXFAT_ATTR_RWMASK | EXFAT_ATTR_READONLY);
 	else
-		EXFAT_I(inode)->attr = attr & ATTR_RWMASK;
+		EXFAT_I(inode)->attr = attr & EXFAT_ATTR_RWMASK;
 }
 
 static inline bool exfat_is_last_sector_in_cluster(struct exfat_sb_info *sbi,

fs/exfat/exfat_raw.h

@@ -64,15 +64,16 @@
 #define CS_DEFAULT		2
 
 /* file attributes */
-#define ATTR_READONLY		0x0001
-#define ATTR_HIDDEN		0x0002
-#define ATTR_SYSTEM		0x0004
-#define ATTR_VOLUME		0x0008
-#define ATTR_SUBDIR		0x0010
-#define ATTR_ARCHIVE		0x0020
-
-#define ATTR_RWMASK		(ATTR_HIDDEN | ATTR_SYSTEM | ATTR_VOLUME | \
-				 ATTR_SUBDIR | ATTR_ARCHIVE)
+#define EXFAT_ATTR_READONLY	0x0001
+#define EXFAT_ATTR_HIDDEN	0x0002
+#define EXFAT_ATTR_SYSTEM	0x0004
+#define EXFAT_ATTR_VOLUME	0x0008
+#define EXFAT_ATTR_SUBDIR	0x0010
+#define EXFAT_ATTR_ARCHIVE	0x0020
+
+#define EXFAT_ATTR_RWMASK	(EXFAT_ATTR_HIDDEN | EXFAT_ATTR_SYSTEM | \
+				 EXFAT_ATTR_VOLUME | EXFAT_ATTR_SUBDIR | \
+				 EXFAT_ATTR_ARCHIVE)
 
 #define BOOTSEC_JUMP_BOOT_LEN		3
 #define BOOTSEC_FS_NAME_LEN		8

fs/exfat/file.c

@@ -8,6 +8,9 @@
 #include <linux/cred.h>
 #include <linux/buffer_head.h>
 #include <linux/blkdev.h>
+#include <linux/fsnotify.h>
+#include <linux/security.h>
+#include <linux/msdos_fs.h>
 
 #include "exfat_raw.h"
 #include "exfat_fs.h"
@@ -144,7 +147,7 @@ int __exfat_truncate(struct inode *inode)
 	}
 
 	if (ei->type == TYPE_FILE)
-		ei->attr |= ATTR_ARCHIVE;
+		ei->attr |= EXFAT_ATTR_ARCHIVE;
 
 	/*
 	 * update the directory entry
@@ -315,6 +318,93 @@ 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 &= (EXFAT_ATTR_READONLY | EXFAT_ATTR_HIDDEN | EXFAT_ATTR_SYSTEM |
+		 EXFAT_ATTR_ARCHIVE);
+	attr |= (is_dir ? EXFAT_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 != EXFAT_ATTR_SUBDIR) {
+		err = -EINVAL;
+		goto out_unlock_inode;
+	}
+
+	if (((attr | oldattr) & EXFAT_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;
@@ -345,8 +435,13 @@ 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 FAT_IOCTL_GET_ATTRIBUTES:
+		return exfat_ioctl_get_attributes(inode, user_attr);
+	case FAT_IOCTL_SET_ATTRIBUTES:
+		return exfat_ioctl_set_attributes(filp, user_attr);
 	case FITRIM:
 		return exfat_ioctl_fitrim(inode, arg);
 	default:

fs/exfat/inode.c

@@ -400,9 +400,9 @@ static int exfat_write_end(struct file *file, struct address_space *mapping,
 	if (err < len)
 		exfat_write_failed(mapping, pos+len);
 
-	if (!(err < 0) && !(ei->attr & ATTR_ARCHIVE)) {
+	if (!(err < 0) && !(ei->attr & EXFAT_ATTR_ARCHIVE)) {
 		inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
-		ei->attr |= ATTR_ARCHIVE;
+		ei->attr |= EXFAT_ATTR_ARCHIVE;
 		mark_inode_dirty(inode);
 	}
 
@@ -550,7 +550,7 @@ static int exfat_fill_inode(struct inode *inode, struct exfat_dir_entry *info)
 	inode_inc_iversion(inode);
 	inode->i_generation = get_random_u32();
 
-	if (info->attr & ATTR_SUBDIR) { /* directory */
+	if (info->attr & EXFAT_ATTR_SUBDIR) { /* directory */
 		inode->i_generation &= ~1;
 		inode->i_mode = exfat_make_mode(sbi, info->attr, 0777);
 		inode->i_op = &exfat_dir_inode_operations;

fs/exfat/namei.c

@@ -534,12 +534,12 @@ static int exfat_add_entry(struct inode *inode, const char *path,
 	info->type = type;
 
 	if (type == TYPE_FILE) {
-		info->attr = ATTR_ARCHIVE;
+		info->attr = EXFAT_ATTR_ARCHIVE;
 		info->start_clu = EXFAT_EOF_CLUSTER;
 		info->size = 0;
 		info->num_subdirs = 0;
 	} else {
-		info->attr = ATTR_SUBDIR;
+		info->attr = EXFAT_ATTR_SUBDIR;
 		info->start_clu = start_clu;
 		info->size = clu_size;
 		info->num_subdirs = EXFAT_MIN_SUBDIR;
@@ -1033,8 +1033,8 @@ static int exfat_rename_file(struct inode *inode, struct exfat_chain *p_dir,
 
 		*epnew = *epold;
 		if (exfat_get_entry_type(epnew) == TYPE_FILE) {
-			epnew->dentry.file.attr |= cpu_to_le16(ATTR_ARCHIVE);
-			ei->attr |= ATTR_ARCHIVE;
+			epnew->dentry.file.attr |= cpu_to_le16(EXFAT_ATTR_ARCHIVE);
+			ei->attr |= EXFAT_ATTR_ARCHIVE;
 		}
 		exfat_update_bh(new_bh, sync);
 		brelse(old_bh);
@@ -1065,8 +1065,8 @@ static int exfat_rename_file(struct inode *inode, struct exfat_chain *p_dir,
 		ei->entry = newentry;
 	} else {
 		if (exfat_get_entry_type(epold) == TYPE_FILE) {
-			epold->dentry.file.attr |= cpu_to_le16(ATTR_ARCHIVE);
-			ei->attr |= ATTR_ARCHIVE;
+			epold->dentry.file.attr |= cpu_to_le16(EXFAT_ATTR_ARCHIVE);
+			ei->attr |= EXFAT_ATTR_ARCHIVE;
 		}
 		exfat_update_bh(old_bh, sync);
 		brelse(old_bh);
@@ -1114,8 +1114,8 @@ static int exfat_move_file(struct inode *inode, struct exfat_chain *p_olddir,
 
 	*epnew = *epmov;
 	if (exfat_get_entry_type(epnew) == TYPE_FILE) {
-		epnew->dentry.file.attr |= cpu_to_le16(ATTR_ARCHIVE);
-		ei->attr |= ATTR_ARCHIVE;
+		epnew->dentry.file.attr |= cpu_to_le16(EXFAT_ATTR_ARCHIVE);
+		ei->attr |= EXFAT_ATTR_ARCHIVE;
 	}
 	exfat_update_bh(new_bh, IS_DIRSYNC(inode));
 	brelse(mov_bh);

fs/exfat/super.c

@@ -360,7 +360,7 @@ static int exfat_read_root(struct inode *inode)
 	inode->i_gid = sbi->options.fs_gid;
 	inode_inc_iversion(inode);
 	inode->i_generation = 0;
-	inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);
+	inode->i_mode = exfat_make_mode(sbi, EXFAT_ATTR_SUBDIR, 0777);
 	inode->i_op = &exfat_dir_inode_operations;
 	inode->i_fop = &exfat_dir_operations;
 
@@ -369,7 +369,7 @@ static int exfat_read_root(struct inode *inode)
 	ei->i_size_aligned = i_size_read(inode);
 	ei->i_size_ondisk = i_size_read(inode);
 
-	exfat_save_attr(inode, ATTR_SUBDIR);
+	exfat_save_attr(inode, EXFAT_ATTR_SUBDIR);
 	ei->i_crtime = simple_inode_init_ts(inode);
 	exfat_truncate_inode_atime(inode);
 	return 0;