Patch "hfsplus: Don't clear SGID when inheriting ACLs" has been added to the 4.12-stable tree

This is a note to let you know that I've just added the patch titled

hfsplus: Don't clear SGID when inheriting ACLs

to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
hfsplus-don-t-clear-sgid-when-inheriting-acls.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jan Kara <[email protected]>
Date: Wed, 21 Jun 2017 15:02:47 +0200
Subject: hfsplus: Don't clear SGID when inheriting ACLs

From: Jan Kara <[email protected]>

commit 84969465ddc4f8aeb3b993123b571aa01c5f2683 upstream.

When new directory 'DIR1' is created in a directory 'DIR0' with SGID bit set, DIR1 is expected to have SGID bit set (and owning group equal to the owning group of 'DIR0'). However when 'DIR0' also has some default ACLs that 'DIR1' inherits, setting these ACLs will result in SGID bit on 'DIR1' to get cleared if user is not member of the owning group.

Fix the problem by creating __hfsplus_set_posix_acl() function that does not call posix_acl_update_mode() and use it when inheriting ACLs. That prevents SGID bit clearing and the mode has been properly set by posix_acl_create() anyway.

---
 fs/hfsplus/posix_acl.c |   30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

@@ -51,8 +51,8 @@ struct posix_acl *hfsplus_get_posix_acl(
 	return acl;
 }
 
-int hfsplus_set_posix_acl(struct inode *inode, struct posix_acl *acl,
-		int type)
+static int __hfsplus_set_posix_acl(struct inode *inode, struct posix_acl *acl,
+				   int type)
 {
 	int err;
 	char *xattr_name;

@@ -64,12 +64,6 @@ int hfsplus_set_posix_acl(struct inode *
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		xattr_name = XATTR_NAME_POSIX_ACL_ACCESS;
-		if (acl) {
-			err = posix_acl_update_mode(inode, &inode->i_mode, &acl);
-			if (err)
-				return err;
-		}
-		err = 0;
 		break;
 
 	case ACL_TYPE_DEFAULT:

@@ -105,6 +99,18 @@ end_set_acl:
 	return err;
 }
 
+int hfsplus_set_posix_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+	int err;
+
+	if (type == ACL_TYPE_ACCESS && acl) {
+		err = posix_acl_update_mode(inode, &inode->i_mode, &acl);
+		if (err)
+			return err;
+	}
+	return __hfsplus_set_posix_acl(inode, acl, type);
+}
+
 int hfsplus_init_posix_acl(struct inode *inode, struct inode *dir)
 {
 	int err = 0;

@@ -122,15 +128,15 @@ int hfsplus_init_posix_acl(struct inode
 		return err;
 
 	if (default_acl) {
-		err = hfsplus_set_posix_acl(inode, default_acl,
-					    ACL_TYPE_DEFAULT);
+		err = __hfsplus_set_posix_acl(inode, default_acl,
+					      ACL_TYPE_DEFAULT);
 		posix_acl_release(default_acl);
 	}
 
 	if (acl) {
 		if (!err)
-			err = hfsplus_set_posix_acl(inode, acl,
-						    ACL_TYPE_ACCESS);
+			err = __hfsplus_set_posix_acl(inode, acl,
+						      ACL_TYPE_ACCESS);
 		posix_acl_release(acl);
 	}
 	return err;

Patches currently in stable-queue which might be from [email protected] are

queue-4.12/f2fs-don-t-clear-sgid-when-inheriting-acls.patch queue-4.12/ext2-don-t-clear-sgid-when-inheriting-acls.patch queue-4.12/scsi-avoid-that-scsi_exit_rq-triggers-a-use-after-free.patch queue-4.12/hfsplus-don-t-clear-sgid-when-inheriting-acls.patch queue-4.12/btrfs-don-t-clear-sgid-when-inheriting-acls.patch queue-4.12/xfs-don-t-clear-sgid-when-inheriting-acls.patch queue-4.12/udf-fix-races-with-i_size-changes-during-readpage.patch queue-4.12/udf-fix-deadlock-between-writeback-and-udf_setsize.patch