fs: merge xattr_acl.c into posix_acl.c

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 173 insertions, 7 deletions

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 8bd2135b7f82..359d70b0e947 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -1,10 +1,8 @@
 /*
- * linux/fs/posix_acl.c
+ * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org>
  *
- *  Copyright (C) 2002 by Andreas Gruenbacher <a.gruenbacher@computer.org>
- *
- *  Fixes from William Schumacher incorporated on 15 March 2001.
- *     (Reported by Charles Bertsch, <CBertsch@microtest.com>).
+ * Fixes from William Schumacher incorporated on 15 March 2001.
+ *    (Reported by Charles Bertsch, <CBertsch@microtest.com>).
  */
 
 /*
@@ -18,9 +16,9 @@
 #include <linux/fs.h>
 #include <linux/sched.h>
 #include <linux/posix_acl.h>
+#include <linux/posix_acl_xattr.h>
 #include <linux/export.h>
-
-#include <linux/errno.h>
+#include <linux/user_namespace.h>
 
 EXPORT_SYMBOL(posix_acl_init);
 EXPORT_SYMBOL(posix_acl_alloc);
@@ -418,3 +416,171 @@ posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
         return err;
 }
 EXPORT_SYMBOL(posix_acl_chmod);
+
+/*
+ * Fix up the uids and gids in posix acl extended attributes in place.
+ */
+static void posix_acl_fix_xattr_userns(
+        struct user_namespace *to, struct user_namespace *from,
+        void *value, size_t size)
+{
+        posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
+        posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
+        int count;
+        kuid_t uid;
+        kgid_t gid;
+
+        if (!value)
+                return;
+        if (size < sizeof(posix_acl_xattr_header))
+                return;
+        if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
+                return;
+
+        count = posix_acl_xattr_count(size);
+        if (count < 0)
+                return;
+        if (count == 0)
+                return;
+
+        for (end = entry + count; entry != end; entry++) {
+                switch(le16_to_cpu(entry->e_tag)) {
+                case ACL_USER:
+                        uid = make_kuid(from, le32_to_cpu(entry->e_id));
+                        entry->e_id = cpu_to_le32(from_kuid(to, uid));
+                        break;
+                case ACL_GROUP:
+                        gid = make_kgid(from, le32_to_cpu(entry->e_id));
+                        entry->e_id = cpu_to_le32(from_kgid(to, gid));
+                        break;
+                default:
+                        break;
+                }
+        }
+}
+
+void posix_acl_fix_xattr_from_user(void *value, size_t size)
+{
+        struct user_namespace *user_ns = current_user_ns();
+        if (user_ns == &init_user_ns)
+                return;
+        posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
+}
+
+void posix_acl_fix_xattr_to_user(void *value, size_t size)
+{
+        struct user_namespace *user_ns = current_user_ns();
+        if (user_ns == &init_user_ns)
+                return;
+        posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
+}
+
+/*
+ * Convert from extended attribute to in-memory representation.
+ */
+struct posix_acl *
+posix_acl_from_xattr(struct user_namespace *user_ns,
+                     const void *value, size_t size)
+{
+        posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
+        posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
+        int count;
+        struct posix_acl *acl;
+        struct posix_acl_entry *acl_e;
+
+        if (!value)
+                return NULL;
+        if (size < sizeof(posix_acl_xattr_header))
+                 return ERR_PTR(-EINVAL);
+        if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
+                return ERR_PTR(-EOPNOTSUPP);
+
+        count = posix_acl_xattr_count(size);
+        if (count < 0)
+                return ERR_PTR(-EINVAL);
+        if (count == 0)
+                return NULL;
+        
+        acl = posix_acl_alloc(count, GFP_NOFS);
+        if (!acl)
+                return ERR_PTR(-ENOMEM);
+        acl_e = acl->a_entries;
+        
+        for (end = entry + count; entry != end; acl_e++, entry++) {
+                acl_e->e_tag  = le16_to_cpu(entry->e_tag);
+                acl_e->e_perm = le16_to_cpu(entry->e_perm);
+
+                switch(acl_e->e_tag) {
+                        case ACL_USER_OBJ:
+                        case ACL_GROUP_OBJ:
+                        case ACL_MASK:
+                        case ACL_OTHER:
+                                break;
+
+                        case ACL_USER:
+                                acl_e->e_uid =
+                                        make_kuid(user_ns,
+                                                  le32_to_cpu(entry->e_id));
+                                if (!uid_valid(acl_e->e_uid))
+                                        goto fail;
+                                break;
+                        case ACL_GROUP:
+                                acl_e->e_gid =
+                                        make_kgid(user_ns,
+                                                  le32_to_cpu(entry->e_id));
+                                if (!gid_valid(acl_e->e_gid))
+                                        goto fail;
+                                break;
+
+                        default:
+                                goto fail;
+                }
+        }
+        return acl;
+
+fail:
+        posix_acl_release(acl);
+        return ERR_PTR(-EINVAL);
+}
+EXPORT_SYMBOL (posix_acl_from_xattr);
+
+/*
+ * Convert from in-memory to extended attribute representation.
+ */
+int
+posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
+                   void *buffer, size_t size)
+{
+        posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
+        posix_acl_xattr_entry *ext_entry = ext_acl->a_entries;
+        int real_size, n;
+
+        real_size = posix_acl_xattr_size(acl->a_count);
+        if (!buffer)
+                return real_size;
+        if (real_size > size)
+                return -ERANGE;
+        
+        ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
+
+        for (n=0; n < acl->a_count; n++, ext_entry++) {
+                const struct posix_acl_entry *acl_e = &acl->a_entries[n];
+                ext_entry->e_tag  = cpu_to_le16(acl_e->e_tag);
+                ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
+                switch(acl_e->e_tag) {
+                case ACL_USER:
+                        ext_entry->e_id =
+                                cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
+                        break;
+                case ACL_GROUP:
+                        ext_entry->e_id =
+                                cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
+                        break;
+                default:
+                        ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
+                        break;
+                }
+        }
+        return real_size;
+}
+EXPORT_SYMBOL (posix_acl_to_xattr);