reiserfs: Switch to security_inode_init_security()

In preparation for removing security_old_inode_init_security(), switch to
security_inode_init_security(). Commit 572302af1258 ("reiserfs: Add missing
calls to reiserfs_security_free()") fixed possible memory leaks and another
issue related to adding an xattr at inode creation time.

Define the initxattrs callback reiserfs_initxattrs(), to populate the
name/value/len triple in the reiserfs_security_handle() with the first
xattr provided by LSMs. Make a copy of the xattr value, as
security_inode_init_security() frees it.

After the call to security_inode_init_security(), remove the check for
returning -EOPNOTSUPP, as security_inode_init_security() changes it to
zero.

Multiple xattrs are currently not supported, as the
reiserfs_security_handle structure is exported to user space. As a
consequence, even if EVM is invoked, it will not provide an xattr (if it
is not the first to set it, its xattr will be discarded; if it is the
first, it does not have xattrs to calculate the HMAC on).

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/fs/reiserfs/xattr_security.c b/fs/reiserfs/xattr_security.c
index 41c0ea8..6bffdf9 100644 (file)
--- a/fs/reiserfs/xattr_security.c
+++ b/fs/reiserfs/xattr_security.c
@@ -39,6 +39,22 @@ static bool security_list(struct dentry *dentry)
        return !IS_PRIVATE(d_inode(dentry));
 }
 
+static int
+reiserfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+                   void *fs_info)
+{
+       struct reiserfs_security_handle *sec = fs_info;
+
+       sec->value = kmemdup(xattr_array->value, xattr_array->value_len,
+                            GFP_KERNEL);
+       if (!sec->value)
+               return -ENOMEM;
+
+       sec->name = xattr_array->name;
+       sec->length = xattr_array->value_len;
+       return 0;
+}
+
 /* Initializes the security context for a new inode and returns the number
  * of blocks needed for the transaction. If successful, reiserfs_security
  * must be released using reiserfs_security_free when the caller is done. */
@@ -56,12 +72,9 @@ int reiserfs_security_init(struct inode *dir, struct inode *inode,
        if (IS_PRIVATE(dir))
                return 0;
 
-       error = security_old_inode_init_security(inode, dir, qstr, &sec->name,
-                                                &sec->value, &sec->length);
+       error = security_inode_init_security(inode, dir, qstr,
+                                            &reiserfs_initxattrs, sec);
        if (error) {
-               if (error == -EOPNOTSUPP)
-                       error = 0;
-
                sec->name = NULL;
                sec->value = NULL;
                sec->length = 0;