userns: Convert extN to support kuids and kgids in posix acls

Convert ext2, ext3, and ext4 to fully support the posix acl changes,
using e_uid e_gid instead e_id.

Enabled building with posix acls enabled, all filesystems supporting
user namespaces, now also support posix acls when user namespaces are enabled.

Cc: Theodore Tso <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

1 files changed, 20 insertions, 8 deletions

diff --git a/fs/ext3/acl.c b/fs/ext3/acl.c
index 2cf6a8044c80..dbb5ad59a7fc 100644
--- a/fs/ext3/acl.c
+++ b/fs/ext3/acl.c
@@ -48,16 +48,23 @@ ext3_acl_from_disk(const void *value, size_t size)
                         case ACL_OTHER:
                                 value = (char *)value +
                                         sizeof(ext3_acl_entry_short);
-                                acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
                                 break;
 
                         case ACL_USER:
+                                value = (char *)value + sizeof(ext3_acl_entry);
+                                if ((char *)value > end)
+                                        goto fail;
+                                acl->a_entries[n].e_uid =
+                                        make_kuid(&init_user_ns,
+                                                  le32_to_cpu(entry->e_id));
+                                break;
                         case ACL_GROUP:
                                 value = (char *)value + sizeof(ext3_acl_entry);
                                 if ((char *)value > end)
                                         goto fail;
-                                acl->a_entries[n].e_id =
-                                        le32_to_cpu(entry->e_id);
+                                acl->a_entries[n].e_gid =
+                                        make_kgid(&init_user_ns,
+                                                  le32_to_cpu(entry->e_id));
                                 break;
 
                         default:
@@ -91,14 +98,19 @@ ext3_acl_to_disk(const struct posix_acl *acl, size_t *size)
         ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
         e = (char *)ext_acl + sizeof(ext3_acl_header);
         for (n=0; n < acl->a_count; n++) {
+                const struct posix_acl_entry *acl_e = &acl->a_entries[n];
                 ext3_acl_entry *entry = (ext3_acl_entry *)e;
-                entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
-                entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
-                switch(acl->a_entries[n].e_tag) {
+                entry->e_tag  = cpu_to_le16(acl_e->e_tag);
+                entry->e_perm = cpu_to_le16(acl_e->e_perm);
+                switch(acl_e->e_tag) {
                         case ACL_USER:
+                                entry->e_id = cpu_to_le32(
+                                        from_kuid(&init_user_ns, acl_e->e_uid));
+                                e += sizeof(ext3_acl_entry);
+                                break;
                         case ACL_GROUP:
-                                entry->e_id =
-                                        cpu_to_le32(acl->a_entries[n].e_id);
+                                entry->e_id = cpu_to_le32(
+                                        from_kgid(&init_user_ns, acl_e->e_gid));
                                 e += sizeof(ext3_acl_entry);
                                 break;