From patchwork Sat Feb 25 01:41:00 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Deepa Dinamani X-Patchwork-Id: 9591421 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2D59460471 for ; Sat, 25 Feb 2017 01:42:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1BE3228678 for ; Sat, 25 Feb 2017 01:42:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 10C5428655; Sat, 25 Feb 2017 01:42:26 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7EFF3275A2 for ; Sat, 25 Feb 2017 01:42:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751659AbdBYBmS (ORCPT ); Fri, 24 Feb 2017 20:42:18 -0500 Received: from mail-pg0-f67.google.com ([74.125.83.67]:35956 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751583AbdBYBmA (ORCPT ); Fri, 24 Feb 2017 20:42:00 -0500 Received: by mail-pg0-f67.google.com with SMTP id z128so4984248pgb.3; Fri, 24 Feb 2017 17:41:20 -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=0ikbFA0vlxs7Jvt821L0aYAvjr9WR/978WyftWWQ5TQ=; b=XMkDDehGd6OiMewLrjh3O0XuIyMrgc3Nua4vpkdhBn0PHOHGvlNXTBnKWgD/PLITZd LwT45hCu+PB9a1ZpWMHRf6G/dsXWBngGz5mVCeMTGK+MZmvd+Uf9Kqdd0KCYDSgPGqG4 x9F8PRvb+ZfBmZdCUzW89XDTrlNqHNkW+ZU41uejve2AjQbYg0O6SHx8v4ivd+3AClqW FiU5YFRualeL3h7AdSWwo630wbY/BP0y+FxMnXx3Ec2bcN6WcXs15OtFTRLTWZL8T/04 8IPCggxVZvWaUz4JEHbGBQ8QYBLmNrv1E5383+lOOkaDeKQFfxupchBQkA79Q6g62FIf Pf3Q== 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=0ikbFA0vlxs7Jvt821L0aYAvjr9WR/978WyftWWQ5TQ=; b=Egz+bAEeRmYw48lnOsHIgK59zH3SZJqwuuWb/ucxQE3RET/f03Kt5U/zo2mfMGFUD6 hFOf0xOd7THJ7Yc/AcExeuPh4C9qACQm2L46UcZF/vPn3zNg7NxY3nN7hY0nZqS7HpiV EFtfTnKMsv738jSKJkyFzaxeYOS43CEy//+Gy5CNEQlJkjM9wn419sE7TV9yvXtlzhhg 7Whkw/S/nmLUHQM5hu/hxZgH03u+i5bYMYPYzUkuzzdzURHQy48hlHqkLYpLwXbUftAu hkUpWpYISH9ZzWL8KB3FdFwrPbN4fW6caQuuPtMFoPE+gsmV9xJjk+d5WOBlzhfT6k65 dgtw== X-Gm-Message-State: AMke39mNRi+PBWnzMPGFlsvq7qRor0Rg2frXTHR7dKEixOZ9cTYoSrq6DmdKiTZz/fRFLw== X-Received: by 10.84.231.133 with SMTP id g5mr7958587plk.59.1487986879726; Fri, 24 Feb 2017 17:41:19 -0800 (PST) Received: from deepa-ubuntu.hsd1.ca.comcast.net ([2601:647:5000:6620:d459:bd54:9ed4:a3f5]) by smtp.gmail.com with ESMTPSA id o24sm17175001pfj.78.2017.02.24.17.41.18 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 24 Feb 2017 17:41:19 -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 v4 2/5] vfs: Add checks for filesystem timestamp limits Date: Fri, 24 Feb 2017 17:41:00 -0800 Message-Id: <1487986863-6005-3-git-send-email-deepa.kernel@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1487986863-6005-1-git-send-email-deepa.kernel@gmail.com> References: <1487986863-6005-1-git-send-email-deepa.kernel@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 | 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 +++++++ 8 files changed, 53 insertions(+), 1 deletion(-) diff --git a/fs/inode.c b/fs/inode.c index 0b3ee89..7967f9c 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 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),