From patchwork Sat Feb 18 23:30:05 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Deepa Dinamani X-Patchwork-Id: 729477 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 3vQmQy48M7z9s7w for ; Sun, 19 Feb 2017 10:32:58 +1100 (AEDT) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="WRSqFz3n"; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751505AbdBRXc3 (ORCPT ); Sat, 18 Feb 2017 18:32:29 -0500 Received: from mail-pg0-f68.google.com ([74.125.83.68]:34071 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750816AbdBRXbJ (ORCPT ); Sat, 18 Feb 2017 18:31:09 -0500 Received: by mail-pg0-f68.google.com with SMTP id v184so8191536pgv.1; Sat, 18 Feb 2017 15:30:44 -0800 (PST) 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=R4SxVeZFdASBff2h0GYT/C7CYsxmaKOrvbk/RLPe/4k=; b=WRSqFz3nakXZG7veG51u77ZcqvfbS+babS4fGtegziP/3dCj+Zzp6Uz/JdPKyVceEf NSVKabScswNcaCiFTN+bDkdOARDjcXSDF6bgzsvEqBV3synqpUpwG5IwOuKSIFurGEBM ttAY2v228y1H7eywydkSnfiRsMkNRNRtoYOXc6FcikcL8NV7KV22oNZ7+9SFCW95oW6K eTL+v75PWEDWXYMqmFv6YS9384O6FWWMQBCb0sdIp4dVYJlVH+TY/hJhW9IhnSbJda12 PO0nh36QtfEBRzZK3uLXZtMkFdoMGBrMGNogSQ8vQnqSxPsy6FEkBDHilgro5CvgNftI yMtw== 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=R4SxVeZFdASBff2h0GYT/C7CYsxmaKOrvbk/RLPe/4k=; b=WX+HorkiGekq6OdjWO2zL5fei9HRU6K30iFubDiaToEMNGhg1AHCHNXpVQxfevhNAh q8EE7KHVu7feDdCrS87VWtPoItJU/MXjZUcryoM9/L//0yAsqsas5E8iPUdr3ykTsucU NAzXOHS1lpoQ46yaDc3vYRR+2sT5mx69NR8+fcY+99x/15Mqk9kiBLY7nP4yGWvlXx8C vWyswYljXe6jY8PxJt9oFdbaXBxo6Hjam46qrWQYYKmefqlkb47Kp2Rc01UO4ZA8QMFD 5Z65DANJ2WEaEq1qyyi/a8jv18nqhp2/fxYtDeweBS/V34SDAA5mGDx4qedS0fX/PCCx y5qA== X-Gm-Message-State: AMke39mx70nkejzSQFOPraDTmvi9APXhLxR2hUOmF4O6fih+JpjfHEGH6uPLr9zKPPtPrg== X-Received: by 10.84.225.18 with SMTP id t18mr21392876plj.154.1487460643539; Sat, 18 Feb 2017 15:30:43 -0800 (PST) Received: from deepa-ubuntu.hsd1.ca.comcast.net ([2601:647:5000:6620:e8a1:d9de:f814:c176]) by smtp.gmail.com with ESMTPSA id s24sm27278030pgo.25.2017.02.18.15.30.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sat, 18 Feb 2017 15:30:43 -0800 (PST) From: Deepa Dinamani To: viro@zeniv.linux.org.uk, tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, arnd@arndb.de, y2038@lists.linaro.org Subject: [PATCH v3 2/5] vfs: Add checks for filesystem timestamp limits Date: Sat, 18 Feb 2017 15:30:05 -0800 Message-Id: <1487460608-15697-3-git-send-email-deepa.kernel@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1487460608-15697-1-git-send-email-deepa.kernel@gmail.com> References: <1487460608-15697-1-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 --- fs/inode.c | 13 +++++++++++++ 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 +++++++ 8 files changed, 51 insertions(+), 1 deletion(-) diff --git a/fs/inode.c b/fs/inode.c index 0b3ee89..0573a3e 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -75,6 +75,19 @@ 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) +{ + timestamp_check.check_on = 1; + return 0; +} + +early_param("fstimestampcheck", setup_timestamp_check); + static long get_nr_inodes(void) { int i; diff --git a/fs/internal.h b/fs/internal.h index 11c6d89..4b3cb9e 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 8bfad42..dbf3f1c 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 ef55dfb..e12a32d 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 bb260ce..eda60d9 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1667,6 +1667,13 @@ 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),