From patchwork Mon Feb 24 16:27:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Eric W. Biederman" X-Patchwork-Id: 11400953 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 AB0B913A4 for ; Mon, 24 Feb 2020 16:29:36 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id E5B9A2080D for ; Mon, 24 Feb 2020 16:29:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5B9A2080D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=xmission.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-17893-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 20476 invoked by uid 550); 24 Feb 2020 16:29:34 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 20434 invoked from network); 24 Feb 2020 16:29:33 -0000 From: ebiederm@xmission.com (Eric W. Biederman) To: Linus Torvalds Cc: Al Viro , LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module , Akinobu Mita , Alexey Dobriyan , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Oleg Nesterov , Solar Designer , Alexey Gladkov References: <20200210150519.538333-8-gladkov.alexey@gmail.com> <87v9odlxbr.fsf@x220.int.ebiederm.org> <20200212144921.sykucj4mekcziicz@comp-core-i7-2640m-0182e6> <87tv3vkg1a.fsf@x220.int.ebiederm.org> <87v9obipk9.fsf@x220.int.ebiederm.org> <20200212200335.GO23230@ZenIV.linux.org.uk> <20200212203833.GQ23230@ZenIV.linux.org.uk> <20200212204124.GR23230@ZenIV.linux.org.uk> <87lfp7h422.fsf@x220.int.ebiederm.org> <87pnejf6fz.fsf@x220.int.ebiederm.org> <871rqpaswu.fsf_-_@x220.int.ebiederm.org> <871rqk2brn.fsf_-_@x220.int.ebiederm.org> Date: Mon, 24 Feb 2020 10:27:17 -0600 In-Reply-To: <871rqk2brn.fsf_-_@x220.int.ebiederm.org> (Eric W. Biederman's message of "Mon, 24 Feb 2020 10:25:16 -0600") Message-ID: <87pne40x3u.fsf_-_@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 X-XM-SPF: eid=1j6Gbg-0007qC-Jo;;;mid=<87pne40x3u.fsf_-_@x220.int.ebiederm.org>;;;hst=in01.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1/UflptKI2kFaz4P7DX3c7LedTcEBcQNz8= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on sa07.xmission.com X-Spam-Level: * X-Spam-Status: No, score=1.0 required=8.0 tests=ALL_TRUSTED,BAYES_50, DCC_CHECK_NEGATIVE,T_TooManySym_01,XMGappySubj_01,XMSubLong autolearn=disabled version=3.4.2 X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.5000] * 0.5 XMGappySubj_01 Very gappy subject * 0.7 XMSubLong Long Subject * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa07 1397; Body=1 Fuz1=81] * 0.0 T_TooManySym_01 4+ unique symbols in subject X-Spam-DCC: XMission; sa07 1397; Body=1 Fuz1=81 X-Spam-Combo: *;Linus Torvalds X-Spam-Relay-Country: X-Spam-Timing: total 344 ms - load_scoreonly_sql: 0.06 (0.0%), signal_user_changed: 2.9 (0.9%), b_tie_ro: 1.99 (0.6%), parse: 1.07 (0.3%), extract_message_metadata: 12 (3.4%), get_uri_detail_list: 1.86 (0.5%), tests_pri_-1000: 15 (4.3%), tests_pri_-950: 1.27 (0.4%), tests_pri_-900: 1.07 (0.3%), tests_pri_-90: 28 (8.1%), check_bayes: 26 (7.7%), b_tokenize: 11 (3.2%), b_tok_get_all: 7 (2.1%), b_comp_prob: 2.1 (0.6%), b_tok_touch_all: 3.7 (1.1%), b_finish: 0.66 (0.2%), tests_pri_0: 271 (78.8%), check_dkim_signature: 0.63 (0.2%), check_dkim_adsp: 2.2 (0.6%), poll_dns_idle: 0.68 (0.2%), tests_pri_10: 2.1 (0.6%), tests_pri_500: 7 (2.1%), rewrite_mail: 0.00 (0.0%) Subject: [PATCH v2 2/6] proc: Generalize proc_sys_prune_dcache into proc_prune_siblings_dcache X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) This prepares the way for allowing the pid part of proc to use this dcache pruning code as well. Signed-off-by: Eric W. Biederman --- fs/proc/inode.c | 38 ++++++++++++++++++++++++++++++++++++++ fs/proc/internal.h | 1 + fs/proc/proc_sysctl.c | 35 +---------------------------------- 3 files changed, 40 insertions(+), 34 deletions(-) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index bdae442d5262..74ce4a8d05eb 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -103,6 +103,44 @@ void __init proc_init_kmemcache(void) BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE); } +void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock) +{ + struct inode *inode; + struct proc_inode *ei; + struct hlist_node *node; + struct super_block *sb; + + rcu_read_lock(); + for (;;) { + node = hlist_first_rcu(inodes); + if (!node) + break; + ei = hlist_entry(node, struct proc_inode, sibling_inodes); + spin_lock(lock); + hlist_del_init_rcu(&ei->sibling_inodes); + spin_unlock(lock); + + inode = &ei->vfs_inode; + sb = inode->i_sb; + if (!atomic_inc_not_zero(&sb->s_active)) + continue; + inode = igrab(inode); + rcu_read_unlock(); + if (unlikely(!inode)) { + deactivate_super(sb); + rcu_read_lock(); + continue; + } + + d_prune_aliases(inode); + iput(inode); + deactivate_super(sb); + + rcu_read_lock(); + } + rcu_read_unlock(); +} + static int proc_show_options(struct seq_file *seq, struct dentry *root) { struct super_block *sb = root->d_sb; diff --git a/fs/proc/internal.h b/fs/proc/internal.h index 366cd3aa690b..ba9a991824a5 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -210,6 +210,7 @@ extern const struct inode_operations proc_pid_link_inode_operations; extern const struct super_operations proc_sops; void proc_init_kmemcache(void); +void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock); void set_proc_pid_nlink(void); extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *); extern void proc_entry_rundown(struct proc_dir_entry *); diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 42fbb7f3c587..5da9d7f7ae34 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -269,40 +269,7 @@ static void unuse_table(struct ctl_table_header *p) static void proc_sys_prune_dcache(struct ctl_table_header *head) { - struct inode *inode; - struct proc_inode *ei; - struct hlist_node *node; - struct super_block *sb; - - rcu_read_lock(); - for (;;) { - node = hlist_first_rcu(&head->inodes); - if (!node) - break; - ei = hlist_entry(node, struct proc_inode, sibling_inodes); - spin_lock(&sysctl_lock); - hlist_del_init_rcu(&ei->sibling_inodes); - spin_unlock(&sysctl_lock); - - inode = &ei->vfs_inode; - sb = inode->i_sb; - if (!atomic_inc_not_zero(&sb->s_active)) - continue; - inode = igrab(inode); - rcu_read_unlock(); - if (unlikely(!inode)) { - deactivate_super(sb); - rcu_read_lock(); - continue; - } - - d_prune_aliases(inode); - iput(inode); - deactivate_super(sb); - - rcu_read_lock(); - } - rcu_read_unlock(); + proc_prune_siblings_dcache(&head->inodes, &sysctl_lock); } /* called under sysctl_lock, will reacquire if has to wait */