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, 7 deletions

diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
index 42b95fccfb2f..d3c5b88fd89f 100644
--- a/fs/ext4/acl.c
+++ b/fs/ext4/acl.c
@@ -55,16 +55,23 @@ ext4_acl_from_disk(const void *value, size_t size)
                 case ACL_OTHER:
                         value = (char *)value +
                                 sizeof(ext4_acl_entry_short);
-                        acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
                         break;
 
                 case ACL_USER:
+                        value = (char *)value + sizeof(ext4_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(ext4_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:
@@ -98,13 +105,19 @@ ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
         ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
         e = (char *)ext_acl + sizeof(ext4_acl_header);
         for (n = 0; n < acl->a_count; n++) {
+                const struct posix_acl_entry *acl_e = &acl->a_entries[n];
                 ext4_acl_entry *entry = (ext4_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(ext4_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(ext4_acl_entry);
                         break;