Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933263AbbLGVaW (ORCPT ); Mon, 7 Dec 2015 16:30:22 -0500 Received: from mail-io0-f174.google.com ([209.85.223.174]:36606 "EHLO mail-io0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932984AbbLGVXc (ORCPT ); Mon, 7 Dec 2015 16:23:32 -0500 From: Seth Forshee To: "Eric W. Biederman" , Alexander Viro Cc: Serge Hallyn , Richard Weinberger , Austin S Hemmelgarn , Miklos Szeredi , linux-bcache@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, fuse-devel@lists.sourceforge.net, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov, Seth Forshee Subject: [PATCH v2 09/18] fs: Refuse uid/gid changes which don't map into s_user_ns Date: Mon, 7 Dec 2015 15:21:18 -0600 Message-Id: <1449523289-144238-10-git-send-email-seth.forshee@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1449523289-144238-1-git-send-email-seth.forshee@canonical.com> References: <1449523289-144238-1-git-send-email-seth.forshee@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1306 Lines: 40 Add checks to inode_change_ok to verify that uid and gid changes will map into the superblock's user namespace. If they do not fail with -EOVERFLOW. This cannot be overriden with ATTR_FORCE. Signed-off-by: Seth Forshee Acked-by: Serge Hallyn --- fs/attr.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/attr.c b/fs/attr.c index 6530ced19697..55b46e3aa888 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -42,6 +42,17 @@ int inode_change_ok(const struct inode *inode, struct iattr *attr) return error; } + /* + * Verify that uid/gid changes are valid in the target namespace + * of the superblock. This cannot be overriden using ATTR_FORCE. + */ + if (ia_valid & ATTR_UID && + from_kuid(inode->i_sb->s_user_ns, attr->ia_uid) == (uid_t)-1) + return -EOVERFLOW; + if (ia_valid & ATTR_GID && + from_kgid(inode->i_sb->s_user_ns, attr->ia_gid) == (gid_t)-1) + return -EOVERFLOW; + /* If force is set do it anyway. */ if (ia_valid & ATTR_FORCE) return 0; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/