From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35E01C433DF for ; Mon, 20 Jul 2020 16:28:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 150BA206E9 for ; Mon, 20 Jul 2020 16:28:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="rS5LCpJj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732240AbgGTP7b (ORCPT ); Mon, 20 Jul 2020 11:59:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42002 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730641AbgGTP7R (ORCPT ); Mon, 20 Jul 2020 11:59:17 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B0038C0619D2; Mon, 20 Jul 2020 08:59:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=wapfVARVdu2rPD3BwjJEB1KyGijoqrlGPwEotE0t0IY=; b=rS5LCpJj7ZaZb8gf7tdqf0ITny HIUK9sLiT6OVcFKzRaclbtvxUcg5v0Ve7yva7ffZOU0vt618YY0/E3bERcBB5Wp0cOh6mUvoGJEC6 UON0B6Cph6M/kd4i/jgP5wD8hKh2xKruQOFpXCh0/d88+xguXsMnnV8Vcnsubu8ZQhj4L5dK7SRCp djGwMhvpqxq/Sx1DkrJ/Wh+ZbQPkLdZKQZPgsi7GUvyUmKFU/y2IFYz5iNVXMUpopdu5Gjxp+rjpk R3A6d6qH2w1S9A3pimN/eEwxfsPzbGV38Aj86OtBF8/v48CFmJ20dpoqko65UGpqdeNg8UjetLEIK vcd8umiQ==; Received: from [2001:4bb8:105:4a81:db56:edb1:dbf2:5cc3] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jxYCA-0007nt-0H; Mon, 20 Jul 2020 15:59:14 +0000 From: Christoph Hellwig To: Al Viro , Linus Torvalds Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org Subject: [PATCH 07/24] fs: add a kern_chroot helper Date: Mon, 20 Jul 2020 17:58:45 +0200 Message-Id: <20200720155902.181712-8-hch@lst.de> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200720155902.181712-1-hch@lst.de> References: <20200720155902.181712-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a simple helper for a chroot with a kernelspace name and use it in the early init code instead of relying on the implicit set_fs(KERNEL_DS) there. Remove the now unused ksys_chroot. Signed-off-by: Christoph Hellwig --- drivers/base/devtmpfs.c | 2 +- fs/open.c | 15 ++++++++++----- include/linux/fs.h | 1 + include/linux/syscalls.h | 1 - init/do_mounts.c | 2 +- init/do_mounts_initrd.c | 4 ++-- 6 files changed, 15 insertions(+), 10 deletions(-) diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 2cedeb62706f18..a5126e7be34c8a 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -389,7 +389,7 @@ static int devtmpfs_setup(void *p) if (err) goto out; kern_chdir("/.."); /* will traverse into overmounted root */ - ksys_chroot("."); + kern_chroot("."); out: *(int *)p = err; complete(&setup_done); diff --git a/fs/open.c b/fs/open.c index 3d62f4d2604739..424db905da5f18 100644 --- a/fs/open.c +++ b/fs/open.c @@ -540,15 +540,15 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd) return error; } -int ksys_chroot(const char __user *filename) +static int do_chroot(struct filename *name) { struct path path; int error; unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY; retry: - error = user_path_at(AT_FDCWD, filename, lookup_flags, &path); + error = filename_lookup(AT_FDCWD, name, lookup_flags, &path, NULL); if (error) - goto out; + return error; error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); if (error) @@ -569,13 +569,18 @@ int ksys_chroot(const char __user *filename) lookup_flags |= LOOKUP_REVAL; goto retry; } -out: + putname(name); return error; } +int kern_chroot(const char *filename) +{ + return do_chroot(getname_kernel(filename)); +} + SYSCALL_DEFINE1(chroot, const char __user *, filename) { - return ksys_chroot(filename); + return do_chroot(getname(filename)); } static int chmod_common(const struct path *path, umode_t mode) diff --git a/include/linux/fs.h b/include/linux/fs.h index dccb37407e9bad..0205355bffb1bc 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3672,5 +3672,6 @@ static inline int inode_drain_writes(struct inode *inode) } int kern_chdir(const char *filename); +int kern_chroot(const char *filename); #endif /* _LINUX_FS_H */ diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index f2a181776b0409..a3176d1a521467 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -1236,7 +1236,6 @@ asmlinkage long sys_ni_syscall(void); * the ksys_xyzyyz() functions prototyped below. */ -int ksys_chroot(const char __user *filename); ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count); int ksys_fchown(unsigned int fd, uid_t user, gid_t group); ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count); diff --git a/init/do_mounts.c b/init/do_mounts.c index 8c3fca8e2d3c6e..31b8dedb189b57 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -629,7 +629,7 @@ void __init prepare_namespace(void) out: devtmpfs_mount(); do_kern_mount(".", "/", NULL, MS_MOVE, NULL); - ksys_chroot("."); + kern_chroot("."); } static bool is_tmpfs; diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c index 522554d703b785..1cbc9988d2e0ad 100644 --- a/init/do_mounts_initrd.c +++ b/init/do_mounts_initrd.c @@ -63,7 +63,7 @@ static int __init init_linuxrc(struct subprocess_info *info, struct cred *new) /* move initrd over / and chdir/chroot in initrd root */ kern_chdir("/root"); do_kern_mount(".", "/", NULL, MS_MOVE, NULL); - ksys_chroot("."); + kern_chroot("."); ksys_setsid(); return 0; } @@ -101,7 +101,7 @@ static void __init handle_initrd(void) /* move initrd to rootfs' /old */ do_kern_mount("..", ".", NULL, MS_MOVE, NULL); /* switch root and cwd back to / of rootfs */ - ksys_chroot(".."); + kern_chroot(".."); if (new_decode_dev(real_root_dev) == Root_RAM0) { kern_chdir("/old"); -- 2.27.0