From patchwork Tue Jul 28 16:34:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11689535 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 7981614E3 for ; Tue, 28 Jul 2020 16:35:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B4C2207F5 for ; Tue, 28 Jul 2020 16:35:51 +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="cYH+YcQ8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731692AbgG1Qeq (ORCPT ); Tue, 28 Jul 2020 12:34:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731666AbgG1Qep (ORCPT ); Tue, 28 Jul 2020 12:34:45 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 30A5FC061794; Tue, 28 Jul 2020 09:34:45 -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=/T5H0GjNVGfpRThj07mo+lYP7Tftb5ckql4lMF97imo=; b=cYH+YcQ8/Wy9tfCepfhgOCT1Le ZED6WGyxpTBMOSi+Zt/UTRB7g+dQ4evoH9AIa0zSoSOwmBGR8fe/AroJ7rA7POLVDshZZWndl4LbI w+LoCKoYvwo3yfMV5HGr8k1VITcCMGJqLt1WVyekuqBmm5GMubfwiclDj5kD3hCvG/zcEqvRSqGdS 7sv/w0hJvV1UnZjAqMVIhhjeNneXh4EUCcuV8aT018bG+BYcLu3qqLl2157GX0/3tG2uhOqylq2AP ZjuOudsEseuS+ka1Q0ktBKhLgg0C0PUYiSm6f1OuQhz4cLLcjHcnEyclQlHrDzAxgVT4WhOEl8MJ+ Gm0+zblQ==; Received: from [2001:4bb8:180:6102:fd04:50d8:4827:5508] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1k0SYo-0006zw-Dr; Tue, 28 Jul 2020 16:34:39 +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 12/23] init: add an init_chdir helper Date: Tue, 28 Jul 2020 18:34:05 +0200 Message-Id: <20200728163416.556521-13-hch@lst.de> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200728163416.556521-1-hch@lst.de> References: <20200728163416.556521-1-hch@lst.de> MIME-Version: 1.0 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 to chdir with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_chdir. Signed-off-by: Christoph Hellwig --- drivers/base/devtmpfs.c | 2 +- fs/init.c | 16 ++++++++++++++++ fs/open.c | 7 +------ include/linux/init_syscalls.h | 1 + include/linux/syscalls.h | 1 - init/do_mounts.c | 2 +- init/do_mounts_initrd.c | 8 ++++---- 7 files changed, 24 insertions(+), 13 deletions(-) diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 32af6cb987b428..e48aaba3166b5d 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -412,7 +412,7 @@ static int __init devtmpfs_setup(void *p) err = init_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, NULL); if (err) goto out; - ksys_chdir("/.."); /* will traverse into overmounted root */ + init_chdir("/.."); /* will traverse into overmounted root */ ksys_chroot("."); out: *(int *)p = err; diff --git a/fs/init.c b/fs/init.c index eabd9ed2b51092..64d4e12eba9339 100644 --- a/fs/init.c +++ b/fs/init.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include "internal.h" @@ -38,6 +39,21 @@ int __init init_umount(const char *name, int flags) return path_umount(&path, flags); } +int __init init_chdir(const char *filename) +{ + struct path path; + int error; + + error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path); + if (error) + return error; + error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); + if (!error) + set_fs_pwd(current->fs, &path); + path_put(&path); + return error; +} + int __init init_unlink(const char *pathname) { return do_unlinkat(AT_FDCWD, getname_kernel(pathname)); diff --git a/fs/open.c b/fs/open.c index b316dd6a86a8b9..723e0ac898935e 100644 --- a/fs/open.c +++ b/fs/open.c @@ -482,7 +482,7 @@ SYSCALL_DEFINE2(access, const char __user *, filename, int, mode) return do_faccessat(AT_FDCWD, filename, mode, 0); } -int ksys_chdir(const char __user *filename) +SYSCALL_DEFINE1(chdir, const char __user *, filename) { struct path path; int error; @@ -508,11 +508,6 @@ int ksys_chdir(const char __user *filename) return error; } -SYSCALL_DEFINE1(chdir, const char __user *, filename) -{ - return ksys_chdir(filename); -} - SYSCALL_DEFINE1(fchdir, unsigned int, fd) { struct fd f = fdget_raw(fd); diff --git a/include/linux/init_syscalls.h b/include/linux/init_syscalls.h index abf3af563c0b3a..1e845910ae56e9 100644 --- a/include/linux/init_syscalls.h +++ b/include/linux/init_syscalls.h @@ -3,5 +3,6 @@ int __init init_mount(const char *dev_name, const char *dir_name, const char *type_page, unsigned long flags, void *data_page); int __init init_umount(const char *name, int flags); +int __init init_chdir(const char *filename); int __init init_unlink(const char *pathname); int __init init_rmdir(const char *pathname); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index a7b14258d245e2..31fa67fb9894b3 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 83db87b6e5d1e0..a7581c6e85f268 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"); + init_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 8b44dd017842a8..04627fd22a921f 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"); + init_chdir("/root"); init_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"); + init_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"); + init_chdir("/old"); return; } - ksys_chdir("/"); + init_chdir("/"); ROOT_DEV = new_decode_dev(real_root_dev); mount_root();