From patchwork Sat Apr 8 19:37:44 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Deepa Dinamani X-Patchwork-Id: 748662 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3w0mxG476xz9s76 for ; Sun, 9 Apr 2017 05:39:46 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="k09Ue+jJ"; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752379AbdDHTjQ (ORCPT ); Sat, 8 Apr 2017 15:39:16 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:34268 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752317AbdDHTjM (ORCPT ); Sat, 8 Apr 2017 15:39:12 -0400 Received: by mail-pf0-f193.google.com with SMTP id o126so4569511pfb.1; Sat, 08 Apr 2017 12:39:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=etsA1awauJgHyqLllgJ2xjRcgg5RcYCudkQmO71BzAk=; b=k09Ue+jJAHE4H7503d4eZvJD00llJZ0/Xm+zcb3Z1KaSyOMAXOmNBW3LDaXBCvrufX uFnhg4YvIALgJUPArxPQtGZdSprMeZnA+oDQArW7RoLqtyc0w8ajdrWrPMC+z3WGWPu2 VFekzcUF/irDnLlUx1FTnC+yFgt0HjDQJK5uXfB3vXyHnUhqNec6bBZJD0iSbyE5KF+s 5YvSS0HaGzheaBAMH8xS4cKZpaannLv7Suz9R1dYDxZPyvJOfeimJtMJ9nEqtaS/nihx Q1gUVdKg/dzL7rCq8DdnbItpwtlwZE61/vq1NdqsR2hiL5pQqptleZVwPym1DHKM7MFK pQCw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=etsA1awauJgHyqLllgJ2xjRcgg5RcYCudkQmO71BzAk=; b=amiGl/02KNE8YW4D6DtKyMzGel2XVKeuaCu/RKmPHAo+uy5xJdxf4rG2JdudLpJEw4 cFa3DZUD2QUzdXHAx/xkFq9EhboroX4hmr89qcNui6DCFtCT3J9WA2JspzpP22clTGlm ZwUOC1b5fkjX+jjFqy4qJ86Vz/zqzaE0+CpUi8CSIba83jsnLGdEqzOmKYPr83Qa2ML7 3mymgTrOlYaHbCgZjd6ROfO3rOEiS0w0qPwUx48q5ryraBdwx/TnGLXz7TxluVlcgzAm I5T9CTeicEMS9xe4QH8XPLu+lpKOr0xuwu47TtxG658z2kKy32vnhQ65i3ICNWp3BOg8 /Bcw== X-Gm-Message-State: AFeK/H0l21CYH+yM0X/FHRrvtBULhrB2TsNTMdlL0N7QpklNlb9BOFx4w5LK/w6YFmScwQ== X-Received: by 10.98.73.15 with SMTP id w15mr46589380pfa.218.1491680351654; Sat, 08 Apr 2017 12:39:11 -0700 (PDT) Received: from deepa-ubuntu.hsd1.ca.comcast.net ([2601:647:5000:6620:b9e0:ac:e01a:86f8]) by smtp.gmail.com with ESMTPSA id t12sm16328627pfg.14.2017.04.08.12.39.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sat, 08 Apr 2017 12:39:11 -0700 (PDT) From: Deepa Dinamani To: viro@zeniv.linux.org.uk, tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org Cc: torvalds@linux-foundation.org, tglx@linutronix.de, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, arnd@arndb.de, y2038@lists.linaro.org Subject: [PATCH v5 2/5] vfs: Add checks for filesystem timestamp limits Date: Sat, 8 Apr 2017 12:37:44 -0700 Message-Id: <1491680267-11171-3-git-send-email-deepa.kernel@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1491680267-11171-1-git-send-email-deepa.kernel@gmail.com> References: <1491680267-11171-1-git-send-email-deepa.kernel@gmail.com> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Allow read only mounts for filesystems that do not have maximum timestamps beyond the y2038 expiry timestamp. Also, allow a sysctl override to all such filesystems to be mounted with write permissions. A boot param supports initial override of these checks from the early boot without recompilation. Suggested-by: Arnd Bergmann Signed-off-by: Deepa Dinamani --- Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++ fs/inode.c | 15 +++++++++++++++ fs/internal.h | 2 ++ fs/namespace.c | 12 ++++++++++++ fs/super.c | 7 +++++++ include/linux/fs.h | 1 + include/linux/time64.h | 4 ++++ include/uapi/linux/fs.h | 6 +++++- kernel/sysctl.c | 7 +++++++ 9 files changed, 61 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index c2f220d..57f4a50 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1193,6 +1193,14 @@ can be changed at run time by the max_graph_depth file in the tracefs tracing directory. default: 0 (no limit) + fstimestampcheck + Enable checking of max filesystem time supported + at mount time. The value is checked against y2038 + date: Mon Jan 18 19:14:07 PST 2038. The option + disables rw mount of filesystems that are not able + to represent times beyond y2038 time mentioned above. + This check is off by default. + gamecon.map[2|3]= [HW,JOY] Multisystem joystick and NES/SNES/PSX pad support via parallel port (up to 5 devices per port) diff --git a/fs/inode.c b/fs/inode.c index a9caf53..a0c1522 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -75,6 +75,21 @@ static DEFINE_PER_CPU(unsigned long, nr_unused); static struct kmem_cache *inode_cachep __read_mostly; +struct vfs_max_timestamp_check timestamp_check = { + .timestamp_supported = Y2038_EXPIRY_TIMESTAMP, + .check_on = 0, +}; + +static int __init setup_timestamp_check(char *str) +{ + if (*str) + return 0; + timestamp_check.check_on = 1; + return 1; +} + +__setup("fstimestampcheck", setup_timestamp_check); + static long get_nr_inodes(void) { int i; diff --git a/fs/internal.h b/fs/internal.h index cef253a..76fbcde 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -67,6 +67,8 @@ extern int finish_automount(struct vfsmount *, struct path *); extern int sb_prepare_remount_readonly(struct super_block *); +extern bool sb_file_times_updatable(struct super_block *sb); + extern void __init mnt_init(void); extern int __mnt_want_write(struct vfsmount *); diff --git a/fs/namespace.c b/fs/namespace.c index 6b81c20..fd6e479 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -538,6 +538,18 @@ static void __mnt_unmake_readonly(struct mount *mnt) unlock_mount_hash(); } +bool sb_file_times_updatable(struct super_block *sb) +{ + + if (!timestamp_check.check_on) + return true; + + if (sb->s_time_max > timestamp_check.timestamp_supported) + return true; + + return false; +} + int sb_prepare_remount_readonly(struct super_block *sb) { struct mount *mnt; diff --git a/fs/super.c b/fs/super.c index f9c2241..4e7577b 100644 --- a/fs/super.c +++ b/fs/super.c @@ -1245,6 +1245,13 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data) WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to " "negative value (%lld)\n", type->name, sb->s_maxbytes); + if (!(sb->s_flags & MS_RDONLY) && !sb_file_times_updatable(sb)) { + WARN(1, "File times cannot be updated on the filesystem.\n"); + WARN(1, "Retry mounting the filesystem readonly.\n"); + error = -EROFS; + goto out_sb; + } + up_write(&sb->s_umount); free_secdata(secdata); return root; diff --git a/include/linux/fs.h b/include/linux/fs.h index 63f83440..a39dc8e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -68,6 +68,7 @@ extern struct inodes_stat_t inodes_stat; extern int leases_enable, lease_break_time; extern int sysctl_protected_symlinks; extern int sysctl_protected_hardlinks; +extern struct vfs_max_timestamp_check timestamp_check; struct buffer_head; typedef int (get_block_t)(struct inode *inode, sector_t iblock, diff --git a/include/linux/time64.h b/include/linux/time64.h index 25433b18..906e0b3 100644 --- a/include/linux/time64.h +++ b/include/linux/time64.h @@ -43,6 +43,10 @@ struct itimerspec64 { #define KTIME_MAX ((s64)~((u64)1 << 63)) #define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC) +/* Timestamps on boundary */ +#define Y2038_EXPIRY_TIMESTAMP S32_MAX /* 2147483647 */ +#define Y2106_EXPIRY_TIMESTAMP U32_MAX /* 4294967295 */ + #if __BITS_PER_LONG == 64 static inline struct timespec timespec64_to_timespec(const struct timespec64 ts64) diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 048a85e..125e4ae 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -91,6 +91,11 @@ struct files_stat_struct { unsigned long max_files; /* tunable */ }; +struct vfs_max_timestamp_check { + time64_t timestamp_supported; + int check_on; +}; + struct inodes_stat_t { long nr_inodes; long nr_unused; @@ -100,7 +105,6 @@ struct inodes_stat_t { #define NR_FILE 8192 /* this can well be larger on a larger system */ - /* * These are the fs-independent mount-flags: up to 32 flags are supported */ diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 60474df..d88487c 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1668,6 +1668,13 @@ static struct ctl_table fs_table[] = { .proc_handler = proc_doulongvec_minmax, }, { + .procname = "fs-timestamp-check-on", + .data = ×tamp_check.check_on, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { .procname = "nr_open", .data = &sysctl_nr_open, .maxlen = sizeof(unsigned int),