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 11894C433ED for ; Mon, 20 Jul 2020 15:59:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF764206E9 for ; Mon, 20 Jul 2020 15:59:20 +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="EPa66x/b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732197AbgGTP7U (ORCPT ); Mon, 20 Jul 2020 11:59:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42000 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732181AbgGTP7R (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 57F1AC061794; 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=l+JL70Ce+YaTVJ7gVRD4su4ckCiiydRxKQuxWuaqyks=; b=EPa66x/bR1568pFpWEopUxmjcd GUwQsYShf9hLiFPGrgBWNEYQcTJegnix6N3Gp5WbMr31VQ9B6Ja9IPYMYt4GgwUsVGoet0nnBES0R 7zD8BOvbTHW760MD3WXi2lgrrcoZH6FkCvCLliDVWlIq3OQDqarjsJxghdpyb5Ug7uz9S6h5sQoEe qFfVcp5JRoU8goKHOPrCY2LDnSzCxdwqh23z0uF1k4T24dgGpd0fpL8wstCeo+mu37j528nxn3/1J y0TNbNVUnM8fC/Lh1jyppQGrs4HXuu/rn5TzUo4pQz1+idlmuQgT9PitgcyPgg7lQozLu2fHQhUrj GmvzKPKA==; 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 1jxYC7-0007nV-Rf; Mon, 20 Jul 2020 15:59:12 +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 06/24] fs: add a kern_chdir helper Date: Mon, 20 Jul 2020 17:58:44 +0200 Message-Id: <20200720155902.181712-7-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-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Add a simple helper for a chdir 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_chdir. Signed-off-by: Christoph Hellwig --- drivers/base/devtmpfs.c | 2 +- fs/open.c | 15 ++++++++++----- include/linux/fs.h | 2 ++ include/linux/syscalls.h | 1 - init/do_mounts.c | 2 +- init/do_mounts_initrd.c | 8 ++++---- 6 files changed, 18 insertions(+), 12 deletions(-) diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 03221ca708c91c..2cedeb62706f18 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -388,7 +388,7 @@ static int devtmpfs_setup(void *p) err = do_kern_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, NULL); if (err) goto out; - ksys_chdir("/.."); /* will traverse into overmounted root */ + kern_chdir("/.."); /* will traverse into overmounted root */ ksys_chroot("."); out: *(int *)p = err; diff --git a/fs/open.c b/fs/open.c index b316dd6a86a8b9..3d62f4d2604739 100644 --- a/fs/open.c +++ b/fs/open.c @@ -482,15 +482,15 @@ SYSCALL_DEFINE2(access, const char __user *, filename, int, mode) return do_faccessat(AT_FDCWD, filename, mode, 0); } -int ksys_chdir(const char __user *filename) +static int do_chdir(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) @@ -504,13 +504,18 @@ int ksys_chdir(const char __user *filename) lookup_flags |= LOOKUP_REVAL; goto retry; } -out: + putname(name); return error; } +int kern_chdir(const char *filename) +{ + return do_chdir(getname_kernel(filename)); +} + SYSCALL_DEFINE1(chdir, const char __user *, filename) { - return ksys_chdir(filename); + return do_chdir(getname(filename)); } SYSCALL_DEFINE1(fchdir, unsigned int, fd) diff --git a/include/linux/fs.h b/include/linux/fs.h index fbeadaa1a185fb..dccb37407e9bad 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3671,4 +3671,6 @@ static inline int inode_drain_writes(struct inode *inode) return filemap_write_and_wait(inode->i_mapping); } +int kern_chdir(const char *filename); + #endif /* _LINUX_FS_H */ diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 3b1b8ebcda1d8c..f2a181776b0409 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -1238,7 +1238,6 @@ asmlinkage long sys_ni_syscall(void); int ksys_chroot(const char __user *filename); ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count); -int ksys_chdir(const char __user *filename); 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); void ksys_sync(void); diff --git a/init/do_mounts.c b/init/do_mounts.c index 2fef92a8ed3c15..8c3fca8e2d3c6e 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -408,7 +408,7 @@ static int __init do_mount_root(const char *name, const char *fs, if (ret) goto out; - ksys_chdir("/root"); + kern_chdir("/root"); s = current->fs->pwd.dentry->d_sb; ROOT_DEV = s->s_dev; printk(KERN_INFO diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c index d3858620707893..522554d703b785 100644 --- a/init/do_mounts_initrd.c +++ b/init/do_mounts_initrd.c @@ -61,7 +61,7 @@ static int __init init_linuxrc(struct subprocess_info *info, struct cred *new) ksys_unshare(CLONE_FS | CLONE_FILES); console_on_rootfs(); /* move initrd over / and chdir/chroot in initrd root */ - ksys_chdir("/root"); + kern_chdir("/root"); do_kern_mount(".", "/", NULL, MS_MOVE, NULL); ksys_chroot("."); ksys_setsid(); @@ -82,7 +82,7 @@ static void __init handle_initrd(void) /* mount initrd on rootfs' /root */ mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY); ksys_mkdir("/old", 0700); - ksys_chdir("/old"); + kern_chdir("/old"); /* * In case that a resume from disk is carried out by linuxrc or one of @@ -104,11 +104,11 @@ static void __init handle_initrd(void) ksys_chroot(".."); if (new_decode_dev(real_root_dev) == Root_RAM0) { - ksys_chdir("/old"); + kern_chdir("/old"); return; } - ksys_chdir("/"); + kern_chdir("/"); ROOT_DEV = new_decode_dev(real_root_dev); mount_root(); -- 2.27.0