From patchwork Tue Feb 11 16:57:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 11375995 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7A4D614E3 for ; Tue, 11 Feb 2020 17:00:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5B5A520848 for ; Tue, 11 Feb 2020 17:00:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728537AbgBKRAr (ORCPT ); Tue, 11 Feb 2020 12:00:47 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:53429 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730097AbgBKQ7h (ORCPT ); Tue, 11 Feb 2020 11:59:37 -0500 Received: from ip5f5bf7ec.dynamic.kabel-deutschland.de ([95.91.247.236] helo=wittgenstein.fritz.box) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1j1YsV-00014T-FV; Tue, 11 Feb 2020 16:59:15 +0000 From: Christian Brauner To: =?utf-8?q?St=C3=A9phane_Graber?= , "Eric W. Biederman" , Aleksa Sarai , Jann Horn Cc: smbarber@chromium.org, Alexander Viro , Alexey Dobriyan , Serge Hallyn , James Morris , Kees Cook , Jonathan Corbet , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, containers@lists.linux-foundation.org, linux-security-module@vger.kernel.org, linux-api@vger.kernel.org, Christian Brauner Subject: [PATCH 10/24] stat: handle fsid mappings Date: Tue, 11 Feb 2020 17:57:39 +0100 Message-Id: <20200211165753.356508-11-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200211165753.356508-1-christian.brauner@ubuntu.com> References: <20200211165753.356508-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Switch attribute functions looking up fsids to them up in the fsid mappings. If no fsid mappings are setup the behavior is unchanged, i.e. fsids are looked up in the id mappings. Filesystems that share a superblock in all user namespaces they are mounted in will retain their old semantics even with the introduction of fsidmappings. Signed-off-by: Christian Brauner --- fs/stat.c | 48 +++++++++++++++++++++++++++++++++++--------- include/linux/stat.h | 1 + 2 files changed, 39 insertions(+), 10 deletions(-) diff --git a/fs/stat.c b/fs/stat.c index c38e4c2e1221..1cced54e79d4 100644 --- a/fs/stat.c +++ b/fs/stat.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -77,6 +78,8 @@ int vfs_getattr_nosec(const struct path *path, struct kstat *stat, if (IS_AUTOMOUNT(inode)) stat->attributes |= STATX_ATTR_AUTOMOUNT; + stat->userns_visible = is_userns_visible(inode->i_sb->s_iflags); + if (inode->i_op->getattr) return inode->i_op->getattr(path, stat, request_mask, query_flags); @@ -229,8 +232,13 @@ static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * sta tmp.st_nlink = stat->nlink; if (tmp.st_nlink != stat->nlink) return -EOVERFLOW; - SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); - SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); + if (stat->userns_visible) { + SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); + SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); + } else { + SET_UID(tmp.st_uid, from_kfsuid_munged(current_user_ns(), stat->uid)); + SET_GID(tmp.st_gid, from_kfsgid_munged(current_user_ns(), stat->gid)); + } tmp.st_rdev = old_encode_dev(stat->rdev); #if BITS_PER_LONG == 32 if (stat->size > MAX_NON_LFS) @@ -317,8 +325,13 @@ static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) tmp.st_nlink = stat->nlink; if (tmp.st_nlink != stat->nlink) return -EOVERFLOW; - SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); - SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); + if (stat->userns_visible) { + SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); + SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); + } else { + SET_UID(tmp.st_uid, from_kfsuid_munged(current_user_ns(), stat->uid)); + SET_GID(tmp.st_gid, from_kfsgid_munged(current_user_ns(), stat->gid)); + } tmp.st_rdev = encode_dev(stat->rdev); tmp.st_size = stat->size; tmp.st_atime = stat->atime.tv_sec; @@ -461,8 +474,13 @@ static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) #endif tmp.st_mode = stat->mode; tmp.st_nlink = stat->nlink; - tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid); - tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid); + if (stat->userns_visible) { + tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid); + tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid); + } else { + tmp.st_uid, from_kfsuid_munged(current_user_ns(), stat->uid); + tmp.st_gid, from_kfsgid_munged(current_user_ns(), stat->gid); + } tmp.st_atime = stat->atime.tv_sec; tmp.st_atime_nsec = stat->atime.tv_nsec; tmp.st_mtime = stat->mtime.tv_sec; @@ -534,8 +552,13 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer) tmp.stx_blksize = stat->blksize; tmp.stx_attributes = stat->attributes; tmp.stx_nlink = stat->nlink; - tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid); - tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid); + if (stat->userns_visible) { + tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid); + tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid); + } else { + tmp.stx_uid = from_kfsuid_munged(current_user_ns(), stat->uid); + tmp.stx_gid = from_kfsgid_munged(current_user_ns(), stat->gid); + } tmp.stx_mode = stat->mode; tmp.stx_ino = stat->ino; tmp.stx_size = stat->size; @@ -605,8 +628,13 @@ static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf) tmp.st_nlink = stat->nlink; if (tmp.st_nlink != stat->nlink) return -EOVERFLOW; - SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); - SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); + if (stat->userns_visible) { + SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); + SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); + } else { + SET_UID(tmp.st_uid, from_kfsuid_munged(current_user_ns(), stat->uid)); + SET_GID(tmp.st_gid, from_kfsgid_munged(current_user_ns(), stat->gid)); + } tmp.st_rdev = old_encode_dev(stat->rdev); if ((u64) stat->size > MAX_NON_LFS) return -EOVERFLOW; diff --git a/include/linux/stat.h b/include/linux/stat.h index 528c4baad091..e6d4ba73a970 100644 --- a/include/linux/stat.h +++ b/include/linux/stat.h @@ -47,6 +47,7 @@ struct kstat { struct timespec64 ctime; struct timespec64 btime; /* File creation time */ u64 blocks; + bool userns_visible; }; #endif