Revert "(namespace) Revert "UBUNTU: SAUCE: fs: Don't remove suid for CAP_FSETID in...

BugLink: https://bugs.launchpad.net/bugs/1644165
This reverts commit e47ad83f3ed90397c83577a17ebda2cf0f789552.

The kernel fix for bug #1634964 breaks LXD userspace, in particular the
following commits:

ac7f3f73cb39 (namespace) vfs: Don't modify inodes with a uid or gid unknown to the vfs
ca52383ad6a6 (namespace) vfs: Don't create inodes with a uid or gid unknown to the vfs

LXD 2.0.6 will include changes to support these kernel changes, but it isn't
available yet on xenial, so for now we just revert these commits.

Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/fs/inode.c b/fs/inode.c
index 07453fb3c88d6efc0029170cdd50895a36e4c0b3..91cf406b2b5cf59c68dd4938c2559a996364d302 100644 (file)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1691,7 +1691,8 @@ int should_remove_suid(struct dentry *dentry)
        if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
                kill |= ATTR_KILL_SGID;
 
-       if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode)))
+       if (unlikely(kill && !ns_capable(dentry->d_sb->s_user_ns, CAP_FSETID) &&
+                    S_ISREG(mode)))
                return kill;
 
        return 0;