From b0cd38c7f54c9176f78cce2e2b23e1513bf5a224 Mon Sep 17 00:00:00 2001
From: "Ernesto A. Fernandez" <ernesto.mnd.fernandez@gmail.com>
Date: Tue, 6 Feb 2018 15:49:02 -0800
Subject: [PATCH] hfsplus: honor setgid flag on directories

When creating a file inside a directory that has the setgid flag set, give
the new file the group ID of the parent, and also the setgid flag if it is
a directory itself.

Link: http://lkml.kernel.org/r/20171204192705.GA6101@debian.home
Signed-off-by: Ernesto A. Fernandez <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 fs/hfsplus/dir.c        | 4 ++--
 fs/hfsplus/hfsplus_fs.h | 3 ++-
 fs/hfsplus/inode.c      | 7 +++----
 fs/hfsplus/super.c      | 2 +-
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index e8120a282435d..15e06fb552da0 100644
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -444,7 +444,7 @@ static int hfsplus_symlink(struct inode *dir, struct dentry *dentry,
 	int res = -ENOMEM;
 
 	mutex_lock(&sbi->vh_mutex);
-	inode = hfsplus_new_inode(dir->i_sb, S_IFLNK | S_IRWXUGO);
+	inode = hfsplus_new_inode(dir->i_sb, dir, S_IFLNK | S_IRWXUGO);
 	if (!inode)
 		goto out;
 
@@ -486,7 +486,7 @@ static int hfsplus_mknod(struct inode *dir, struct dentry *dentry,
 	int res = -ENOMEM;
 
 	mutex_lock(&sbi->vh_mutex);
-	inode = hfsplus_new_inode(dir->i_sb, mode);
+	inode = hfsplus_new_inode(dir->i_sb, dir, mode);
 	if (!inode)
 		goto out;
 
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index a015044daa053..d9255abafb81f 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -478,7 +478,8 @@ extern const struct address_space_operations hfsplus_aops;
 extern const struct address_space_operations hfsplus_btree_aops;
 extern const struct dentry_operations hfsplus_dentry_operations;
 
-struct inode *hfsplus_new_inode(struct super_block *sb, umode_t mode);
+struct inode *hfsplus_new_inode(struct super_block *sb, struct inode *dir,
+				umode_t mode);
 void hfsplus_delete_inode(struct inode *inode);
 void hfsplus_inode_read_fork(struct inode *inode,
 			     struct hfsplus_fork_raw *fork);
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index 190c60efbc998..c0c8d433864f1 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -354,7 +354,8 @@ static const struct file_operations hfsplus_file_operations = {
 	.unlocked_ioctl = hfsplus_ioctl,
 };
 
-struct inode *hfsplus_new_inode(struct super_block *sb, umode_t mode)
+struct inode *hfsplus_new_inode(struct super_block *sb, struct inode *dir,
+				umode_t mode)
 {
 	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 	struct inode *inode = new_inode(sb);
@@ -364,9 +365,7 @@ struct inode *hfsplus_new_inode(struct super_block *sb, umode_t mode)
 		return NULL;
 
 	inode->i_ino = sbi->next_cnid++;
-	inode->i_mode = mode;
-	inode->i_uid = current_fsuid();
-	inode->i_gid = current_fsgid();
+	inode_init_owner(inode, dir, mode);
 	set_nlink(inode, 1);
 	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
 
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 1d458b7169572..513c357c734b0 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -549,7 +549,7 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 
 		if (!sbi->hidden_dir) {
 			mutex_lock(&sbi->vh_mutex);
-			sbi->hidden_dir = hfsplus_new_inode(sb, S_IFDIR);
+			sbi->hidden_dir = hfsplus_new_inode(sb, root, S_IFDIR);
 			if (!sbi->hidden_dir) {
 				mutex_unlock(&sbi->vh_mutex);
 				err = -ENOMEM;
-- 
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