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[PATCH 01/14] xfs: Convert uids and gids in xfs acls to/from kuids and k

To: <linux-fsdevel@xxxxxxxxxxxxxxx>
Subject: [PATCH 01/14] xfs: Convert uids and gids in xfs acls to/from kuids and kgids
From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Date: Wed, 13 Mar 2013 15:23:02 -0700
Cc: Linux Containers <containers@xxxxxxxxxxxxxxxxxxxxxxxxxx>, "Serge E. Hallyn" <serge@xxxxxxxxxx>, xfs@xxxxxxxxxxx, Ben Myers <bpm@xxxxxxx>, Alex Elder <elder@xxxxxxxxxx>, Dave Chinner <david@xxxxxxxxxxxxx>, "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <87boan3prc.fsf@xxxxxxxxxxxx>
References: <87boan3prc.fsf@xxxxxxxxxxxx>
From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>

- When reading from disk convert on disk uids and gids to kuids and kgids
- When writing to the disk convert in memory kuids and kgids to uids and gids.
- Don't write e_id as that field only exists when user namespace
  support is disabled.
- Use uid_eq when testing to see if current_fsuid() is allowed to set the
  acls for a file.

Cc: Ben Myers <bpm@xxxxxxx>
Cc: Alex Elder <elder@xxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
 fs/xfs/xfs_acl.c |   23 +++++++++++++++++++----
 1 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index 1d32f1d..ca2aade 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -64,14 +64,17 @@ xfs_acl_from_disk(struct xfs_acl *aclp)
 
                switch (acl_e->e_tag) {
                case ACL_USER:
+                       acl_e->e_uid = make_kuid(&init_user_ns,
+                                                be32_to_cpu(ace->ae_id));
+                       break;
                case ACL_GROUP:
-                       acl_e->e_id = be32_to_cpu(ace->ae_id);
+                       acl_e->e_gid = make_kgid(&init_user_ns,
+                                                be32_to_cpu(ace->ae_id));
                        break;
                case ACL_USER_OBJ:
                case ACL_GROUP_OBJ:
                case ACL_MASK:
                case ACL_OTHER:
-                       acl_e->e_id = ACL_UNDEFINED_ID;
                        break;
                default:
                        goto fail;
@@ -97,8 +100,20 @@ xfs_acl_to_disk(struct xfs_acl *aclp, const struct 
posix_acl *acl)
                acl_e = &acl->a_entries[i];
 
                ace->ae_tag = cpu_to_be32(acl_e->e_tag);
-               ace->ae_id = cpu_to_be32(acl_e->e_id);
                ace->ae_perm = cpu_to_be16(acl_e->e_perm);
+               switch(acl_e->e_tag) {
+               case ACL_USER:
+                       ace->ae_id = cpu_to_be32(
+                               from_kuid(&init_user_ns, acl_e->e_uid));
+                       break;
+               case ACL_GROUP:
+                       ace->ae_id = cpu_to_be32(
+                               from_kgid(&init_user_ns, acl_e->e_gid));
+                       break;
+               default:
+                       ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
+                       break;
+               }
        }
 }
 
@@ -355,7 +370,7 @@ xfs_xattr_acl_set(struct dentry *dentry, const char *name,
                return -EINVAL;
        if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
                return value ? -EACCES : 0;
-       if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
+       if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_FOWNER))
                return -EPERM;
 
        if (!value)
-- 
1.7.5.4

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