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 48D42C433F1 for ; Mon, 20 Jul 2020 15:59:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 21D07206E9 for ; Mon, 20 Jul 2020 15:59:22 +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="u/gfBau8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731368AbgGTP7V (ORCPT ); Mon, 20 Jul 2020 11:59:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731124AbgGTP7U (ORCPT ); Mon, 20 Jul 2020 11:59:20 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6456FC0619D2; Mon, 20 Jul 2020 08:59:20 -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=21w+ZovXtzUYFHjW7zAcq/SvhfaPcQNA2bBLjzfA85I=; b=u/gfBau8lfBl8lCv/Gjz5NsubZ w76/+yxGcjwLvwMSvoOVhBh357tz0mSTy69IR9y8hDVWFW/VNrIddpJx7RF/2fl0YDli5vygc3D3I 6Uv7PzkrJvlSKg1P928YG718uNYPTBiJ4rGfGxgd+ZgIypimlndFBFETTjU8VD9QLoB2aIq8cpQJe jfSFW4o73TyyRghGylTJKHYNUQwqkQfWAV/NdI4TOEIIYgoSzib0yCH2mOc6FsyfHl2Cn6DlS7st7 EKqLf7SWQx4XotdhdHsIFPk9kpmozwvQPuymN7USpIXdOEGw8DXMecs6eD9FKIGiJso2ObI/JZhOG q7Pda19g==; 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 1jxYCB-0007oM-UG; Mon, 20 Jul 2020 15:59:16 +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 08/24] fs: add a kern_access helper Date: Mon, 20 Jul 2020 17:58:46 +0200 Message-Id: <20200720155902.181712-9-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-api-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org Add a simple helper for a access 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_access. Signed-off-by: Christoph Hellwig --- fs/open.c | 37 +++++++++++++++++++++++++------------ include/linux/fs.h | 1 + include/linux/syscalls.h | 7 ------- init/main.c | 3 +-- 4 files changed, 27 insertions(+), 21 deletions(-) diff --git a/fs/open.c b/fs/open.c index 424db905da5f18..2a9457a16b2be2 100644 --- a/fs/open.c +++ b/fs/open.c @@ -394,19 +394,19 @@ static const struct cred *access_override_creds(void) return old_cred; } -long do_faccessat(int dfd, const char __user *filename, int mode, int flags) +static int do_faccessat(int dfd, struct filename *name, int mode, int flags) { struct path path; struct inode *inode; - int res; + int res = -EINVAL; unsigned int lookup_flags = LOOKUP_FOLLOW; const struct cred *old_cred = NULL; if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ - return -EINVAL; + goto out_putname; if (flags & ~(AT_EACCESS | AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) - return -EINVAL; + goto out_putname; if (flags & AT_SYMLINK_NOFOLLOW) lookup_flags &= ~LOOKUP_FOLLOW; @@ -414,15 +414,16 @@ long do_faccessat(int dfd, const char __user *filename, int mode, int flags) lookup_flags |= LOOKUP_EMPTY; if (!(flags & AT_EACCESS)) { + res = -ENOMEM; old_cred = access_override_creds(); if (!old_cred) - return -ENOMEM; + goto out_putname; } retry: - res = user_path_at(dfd, filename, lookup_flags, &path); + res = filename_lookup(dfd, name, lookup_flags, &path, NULL); if (res) - goto out; + goto out_revert_creds; inode = d_backing_inode(path.dentry); @@ -459,27 +460,39 @@ long do_faccessat(int dfd, const char __user *filename, int mode, int flags) lookup_flags |= LOOKUP_REVAL; goto retry; } -out: + putname(name); +out_revert_creds: if (old_cred) revert_creds(old_cred); - return res; +out_putname: + if (!IS_ERR(name)) + putname(name); + return res; +} + +int __init kern_access(const char __user *filename, int mode) +{ + return do_faccessat(AT_FDCWD, getname_kernel(filename), mode, 0); } SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode) { - return do_faccessat(dfd, filename, mode, 0); + return do_faccessat(dfd, getname(filename), mode, 0); } SYSCALL_DEFINE4(faccessat2, int, dfd, const char __user *, filename, int, mode, int, flags) { - return do_faccessat(dfd, filename, mode, flags); + unsigned int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; + struct filename *name = getname_flags(filename, lookup_flags, NULL); + + return do_faccessat(dfd, name, mode, flags); } SYSCALL_DEFINE2(access, const char __user *, filename, int, mode) { - return do_faccessat(AT_FDCWD, filename, mode, 0); + return do_faccessat(AT_FDCWD, getname(filename), mode, 0); } static int do_chdir(struct filename *name) diff --git a/include/linux/fs.h b/include/linux/fs.h index 0205355bffb1bc..0c7672d3f1172f 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3673,5 +3673,6 @@ static inline int inode_drain_writes(struct inode *inode) int kern_chdir(const char *filename); int kern_chroot(const char *filename); +int __init kern_access(const char *filename, int mode); #endif /* _LINUX_FS_H */ diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index a3176d1a521467..b387e3700c68c5 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -1326,13 +1326,6 @@ static inline int ksys_chmod(const char __user *filename, umode_t mode) return do_fchmodat(AT_FDCWD, filename, mode); } -long do_faccessat(int dfd, const char __user *filename, int mode, int flags); - -static inline long ksys_access(const char __user *filename, int mode) -{ - return do_faccessat(AT_FDCWD, filename, mode, 0); -} - extern int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group, int flag); diff --git a/init/main.c b/init/main.c index c2c9143db96795..880f195b61abe1 100644 --- a/init/main.c +++ b/init/main.c @@ -1514,8 +1514,7 @@ static noinline void __init kernel_init_freeable(void) * check if there is an early userspace init. If yes, let it do all * the work */ - if (ksys_access((const char __user *) - ramdisk_execute_command, 0) != 0) { + if (kern_access(ramdisk_execute_command, 0) != 0) { ramdisk_execute_command = NULL; prepare_namespace(); } -- 2.27.0