From patchwork Fri Feb 5 21:33:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Kalesh Singh X-Patchwork-Id: 12070979 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 DA71CC433E0 for ; Fri, 5 Feb 2021 21:36:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE7EC64FC5 for ; Fri, 5 Feb 2021 21:36:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229795AbhBEVfc (ORCPT ); Fri, 5 Feb 2021 16:35:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229725AbhBEVev (ORCPT ); Fri, 5 Feb 2021 16:34:51 -0500 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E3266C06178B for ; Fri, 5 Feb 2021 13:33:58 -0800 (PST) Received: by mail-qk1-x749.google.com with SMTP id m9so6955141qka.22 for ; Fri, 05 Feb 2021 13:33:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:cc :content-transfer-encoding; bh=w382r+buQ4Tx8FdN/ryZgjV6D4PrxeZkE7hCNPLCCTk=; b=Do3cLKKgATj9Sj1wczzer7FsQYo2BGJLV+dlolkVMaamGTbvNtGFsx8B9cjDusaoJ6 PH//GMgsuQfTvFJGb504gwHqFYmglx5t8ajCSi0wjHfPg87LkbKyWXkwy6n6pjLVT7L6 obdgNsN/V1Pbj2Yfog3ATINTeISlKX2QmY91sGRAEa+7Ut5frVD33da8olSv64KKgmTY 1hfq4LWBjd1MWAK9SODnWt6hywEnmqIQ9gB8knT+0X0lqaJGvPZa3hK48Wot+TTQB7uC NQhQRopKwh3fC+Dq4ymwIfzENFP3dBEcffQ9JT2loQ6otxhuzTDLJkfWRqu59R79ZTtA e7IQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :cc:content-transfer-encoding; bh=w382r+buQ4Tx8FdN/ryZgjV6D4PrxeZkE7hCNPLCCTk=; b=Nci/mUdIZdFNQ8tzRcC6eHHqTAhUWubQSJK52/dqrdZUh85Eo6a9pPSPXGsrD0odEB BKRlUXa6FaGeDB8u3D7NnltJqpj+xjs2mhwmEYdJ4noELnugjORGOM6ftQhh1s72cfPo XIkiMpFq/xZjRh5195+xcnjAtfd19yRFkqQ46FeNkL5jGL0YUmI1f+QrGw7DA1UXXUdm XADxRv6Z3aZOk88JfV59hPQlrlPqgtALKrGVB00KLzHQF9zwoNyTYoZ5fztc6h1Xt1Bl HCxPmRegM+/vnCmR0h+InlFL5Z7MUn3QGo0PR6n7kwXgXZ3sIJQz9Q8agKVQ43vvSViR Og6A== X-Gm-Message-State: AOAM532ubtE9jRHzqhcA1s+ZqMswr8QI62jtroVgJ4IFyWMwT6JoZFf0 dc7d3WJP6r6dF2Rrc/M7P/M+FsQO9d4xUueU6A== X-Google-Smtp-Source: ABdhPJwJT6nr2aaCz5tonDuWMfRWbCDh0aV8dUQFJumYEjyZC6Qyyu+a1DDqD8I8jK3xt7QsBX2BA6k1mXXISmy/sA== Sender: "kaleshsingh via sendgmr" X-Received: from kaleshsingh.c.googlers.com ([fda3:e722:ac3:10:14:4d90:c0a8:2145]) (user=kaleshsingh job=sendgmr) by 2002:a0c:8365:: with SMTP id j92mr6362202qva.19.1612560837960; Fri, 05 Feb 2021 13:33:57 -0800 (PST) Date: Fri, 5 Feb 2021 21:33:43 +0000 Message-Id: <20210205213353.669122-1-kaleshsingh@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.30.0.478.g8a0d178c01-goog Subject: [PATCH v4 1/2] procfs: Allow reading fdinfo with PTRACE_MODE_READ From: Kalesh Singh Cc: jannh@google.com, jeffv@google.com, keescook@chromium.org, surenb@google.com, minchan@kernel.org, hridya@google.com, rdunlap@infradead.org, christian.koenig@amd.com, kernel-team@android.com, Kalesh Singh , Alexey Dobriyan , Jonathan Corbet , Mauro Carvalho Chehab , Andrew Morton , Michal Hocko , Alexey Gladkov , NeilBrown , Szabolcs Nagy , "Eric W. Biederman" , Michel Lespinasse , Bernd Edlinger , Andrei Vagin , Yafang Shao , Christian Brauner , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Android captures per-process system memory state when certain low memory events (e.g a foreground app kill) occur, to identify potential memory hoggers. In order to measure how much memory a process actually consumes, it is necessary to include the DMA buffer sizes for that process in the memory accounting. Since the handle to DMA buffers are raw FDs, it is important to be able to identify which processes have FD references to a DMA buffer. Currently, DMA buffer FDs can be accounted using /proc//fd/* and /proc//fdinfo -- both are only readable by the process owner, as follows: 1. Do a readlink on each FD. 2. If the target path begins with "/dmabuf", then the FD is a dmabuf FD. 3. stat the file to get the dmabuf inode number. 4. Read/ proc//fdinfo/, to get the DMA buffer size. Accessing other processes’ fdinfo requires root privileges. This limits the use of the interface to debugging environments and is not suitable for production builds. Granting root privileges even to a system process increases the attack surface and is highly undesirable. Since fdinfo doesn't permit reading process memory and manipulating process state, allow accessing fdinfo under PTRACE_MODE_READ_FSCRED. Suggested-by: Jann Horn Signed-off-by: Kalesh Singh --- Changes in v2: - Update patch description fs/proc/base.c | 4 ++-- fs/proc/fd.c | 15 ++++++++++++++- 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index b3422cda2a91..a37f9de7103f 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3160,7 +3160,7 @@ static const struct pid_entry tgid_base_stuff[] = { DIR("task", S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations), DIR("fd", S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations), DIR("map_files", S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations), - DIR("fdinfo", S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations), + DIR("fdinfo", S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations), DIR("ns", S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations), #ifdef CONFIG_NET DIR("net", S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations), @@ -3504,7 +3504,7 @@ static const struct inode_operations proc_tid_comm_inode_operations = { */ static const struct pid_entry tid_base_stuff[] = { DIR("fd", S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations), - DIR("fdinfo", S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations), + DIR("fdinfo", S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations), DIR("ns", S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations), #ifdef CONFIG_NET DIR("net", S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations), diff --git a/fs/proc/fd.c b/fs/proc/fd.c index cb51763ed554..585e213301f9 100644 --- a/fs/proc/fd.c +++ b/fs/proc/fd.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -72,6 +73,18 @@ static int seq_show(struct seq_file *m, void *v) static int seq_fdinfo_open(struct inode *inode, struct file *file) { + bool allowed = false; + struct task_struct *task = get_proc_task(inode); + + if (!task) + return -ESRCH; + + allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS); + put_task_struct(task); + + if (!allowed) + return -EACCES; + return single_open(file, seq_show, inode); } @@ -307,7 +320,7 @@ static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry, struct proc_inode *ei; struct inode *inode; - inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUSR); + inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUGO); if (!inode) return ERR_PTR(-ENOENT); From patchwork Fri Feb 5 21:33:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kalesh Singh X-Patchwork-Id: 12070977 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 8CE1AC433DB for ; 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Fri, 05 Feb 2021 13:34:08 -0800 (PST) Date: Fri, 5 Feb 2021 21:33:44 +0000 In-Reply-To: <20210205213353.669122-1-kaleshsingh@google.com> Message-Id: <20210205213353.669122-2-kaleshsingh@google.com> Mime-Version: 1.0 References: <20210205213353.669122-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.30.0.478.g8a0d178c01-goog Subject: [PATCH v4 2/2] dmabuf: Add dmabuf inode number to /proc/*/fdinfo From: Kalesh Singh Cc: jannh@google.com, jeffv@google.com, keescook@chromium.org, surenb@google.com, minchan@kernel.org, hridya@google.com, rdunlap@infradead.org, christian.koenig@amd.com, kernel-team@android.com, Kalesh Singh , Alexey Dobriyan , Jonathan Corbet , Andrew Morton , Mauro Carvalho Chehab , Michal Hocko , Alexey Gladkov , NeilBrown , "Eric W. Biederman" , Michel Lespinasse , Bernd Edlinger , Andrei Vagin , Yafang Shao , Christian Brauner , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org And 'inode_no' field to /proc//fdinfo/ and /proc//task//fdinfo/. The inode numbers can be used to uniquely identify DMA buffers in user space and avoids a dependency on /proc//fd/* when accounting per-process DMA buffer sizes. Signed-off-by: Kalesh Singh Acked-by: Randy Dunlap --- Changes in v4: - Add inode number as common field in fdinfo, per Christian Changes in v3: - Add documentation in proc.rst, per Randy Changes in v2: - Update patch description Documentation/filesystems/proc.rst | 37 +++++++++++++++++++++++++----- fs/proc/fd.c | 5 ++-- 2 files changed, 34 insertions(+), 8 deletions(-) diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index 2fa69f710e2a..db46da32230c 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -1902,18 +1902,20 @@ if precise results are needed. 3.8 /proc//fdinfo/ - Information about opened file --------------------------------------------------------------- This file provides information associated with an opened file. The regular -files have at least three fields -- 'pos', 'flags' and 'mnt_id'. The 'pos' -represents the current offset of the opened file in decimal form [see lseek(2) -for details], 'flags' denotes the octal O_xxx mask the file has been -created with [see open(2) for details] and 'mnt_id' represents mount ID of -the file system containing the opened file [see 3.5 /proc//mountinfo -for details]. +files have at least four fields -- 'pos', 'flags', 'mnt_id' and 'inode_no'. +The 'pos' represents the current offset of the opened file in decimal +form [see lseek(2) for details], 'flags' denotes the octal O_xxx mask the +file has been created with [see open(2) for details] and 'mnt_id' represents +mount ID of the file system containing the opened file [see 3.5 +/proc//mountinfo for details]. 'inode_no' represents the inode number +of the file. A typical output is:: pos: 0 flags: 0100002 mnt_id: 19 + inode_no: 63107 All locks associated with a file descriptor are shown in its fdinfo too:: @@ -1930,6 +1932,7 @@ Eventfd files pos: 0 flags: 04002 mnt_id: 9 + inode_no: 63107 eventfd-count: 5a where 'eventfd-count' is hex value of a counter. @@ -1942,6 +1945,7 @@ Signalfd files pos: 0 flags: 04002 mnt_id: 9 + inode_no: 63107 sigmask: 0000000000000200 where 'sigmask' is hex value of the signal mask associated @@ -1955,6 +1959,7 @@ Epoll files pos: 0 flags: 02 mnt_id: 9 + inode_no: 63107 tfd: 5 events: 1d data: ffffffffffffffff pos:0 ino:61af sdev:7 where 'tfd' is a target file descriptor number in decimal form, @@ -1971,6 +1976,8 @@ For inotify files the format is the following:: pos: 0 flags: 02000000 + mnt_id: 9 + inode_no: 63107 inotify wd:3 ino:9e7e sdev:800013 mask:800afce ignored_mask:0 fhandle-bytes:8 fhandle-type:1 f_handle:7e9e0000640d1b6d where 'wd' is a watch descriptor in decimal form, i.e. a target file @@ -1993,6 +2000,7 @@ For fanotify files the format is:: pos: 0 flags: 02 mnt_id: 9 + inode_no: 63107 fanotify flags:10 event-flags:0 fanotify mnt_id:12 mflags:40 mask:38 ignored_mask:40000003 fanotify ino:4f969 sdev:800013 mflags:0 mask:3b ignored_mask:40000000 fhandle-bytes:8 fhandle-type:1 f_handle:69f90400c275b5b4 @@ -2017,6 +2025,7 @@ Timerfd files pos: 0 flags: 02 mnt_id: 9 + inode_no: 63107 clockid: 0 ticks: 0 settime flags: 01 @@ -2031,6 +2040,22 @@ details]. 'it_value' is remaining time until the timer expiration. with TIMER_ABSTIME option which will be shown in 'settime flags', but 'it_value' still exhibits timer's remaining time. +DMA Buffer files +~~~~~~~~~~~~~~~~ + +:: + + pos: 0 + flags: 04002 + mnt_id: 9 + inode_no: 63107 + size: 32768 + count: 2 + exp_name: system-heap + +where 'size' is the size of the DMA buffer in bytes. 'count' is the file count of +the DMA buffer file. 'exp_name' is the name of the DMA buffer exporter. + 3.9 /proc//map_files - Information about memory mapped files --------------------------------------------------------------------- This directory contains symbolic links which represent memory mapped files diff --git a/fs/proc/fd.c b/fs/proc/fd.c index 585e213301f9..2c25909bf9d1 100644 --- a/fs/proc/fd.c +++ b/fs/proc/fd.c @@ -54,9 +54,10 @@ static int seq_show(struct seq_file *m, void *v) if (ret) return ret; - seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\n", + seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\ninode_no:\t%lu\n", (long long)file->f_pos, f_flags, - real_mount(file->f_path.mnt)->mnt_id); + real_mount(file->f_path.mnt)->mnt_id, + file_inode(file)->i_ino); /* show_fd_locks() never deferences files so a stale value is safe */ show_fd_locks(m, file, files);