From patchwork Fri Mar 27 17:23:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Gladkov X-Patchwork-Id: 11462851 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 702EB13A4 for ; Fri, 27 Mar 2020 17:32:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 58E992073B for ; Fri, 27 Mar 2020 17:32:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727652AbgC0Rbn (ORCPT ); Fri, 27 Mar 2020 13:31:43 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:38818 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726275AbgC0Rbn (ORCPT ); Fri, 27 Mar 2020 13:31:43 -0400 X-Greylist: delayed 464 seconds by postgrey-1.27 at vger.kernel.org; Fri, 27 Mar 2020 13:31:41 EDT Received: from comp-core-i7-2640m-0182e6.redhat.com (ip-89-102-33-211.net.upcbroadband.cz [89.102.33.211]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by raptor.unsafe.ru (Postfix) with ESMTPSA id BEA84209C7; Fri, 27 Mar 2020 17:23:55 +0000 (UTC) From: Alexey Gladkov To: LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module Cc: Akinobu Mita , Alexander Viro , Alexey Dobriyan , Alexey Gladkov , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , "Eric W . Biederman" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Linus Torvalds , Oleg Nesterov Subject: [PATCH v10 1/9] proc: rename struct proc_fs_info to proc_fs_opts Date: Fri, 27 Mar 2020 18:23:23 +0100 Message-Id: <20200327172331.418878-2-gladkov.alexey@gmail.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200327172331.418878-1-gladkov.alexey@gmail.com> References: <20200327172331.418878-1-gladkov.alexey@gmail.com> MIME-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.1 (raptor.unsafe.ru [5.9.43.93]); Fri, 27 Mar 2020 17:23:56 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Reviewed-by: Alexey Dobriyan Signed-off-by: Alexey Gladkov --- fs/proc_namespace.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c index 273ee82d8aa9..9a8b624bc3db 100644 --- a/fs/proc_namespace.c +++ b/fs/proc_namespace.c @@ -37,23 +37,23 @@ static __poll_t mounts_poll(struct file *file, poll_table *wait) return res; } -struct proc_fs_info { +struct proc_fs_opts { int flag; const char *str; }; static int show_sb_opts(struct seq_file *m, struct super_block *sb) { - static const struct proc_fs_info fs_info[] = { + static const struct proc_fs_opts fs_opts[] = { { SB_SYNCHRONOUS, ",sync" }, { SB_DIRSYNC, ",dirsync" }, { SB_MANDLOCK, ",mand" }, { SB_LAZYTIME, ",lazytime" }, { 0, NULL } }; - const struct proc_fs_info *fs_infop; + const struct proc_fs_opts *fs_infop; - for (fs_infop = fs_info; fs_infop->flag; fs_infop++) { + for (fs_infop = fs_opts; fs_infop->flag; fs_infop++) { if (sb->s_flags & fs_infop->flag) seq_puts(m, fs_infop->str); } @@ -63,7 +63,7 @@ static int show_sb_opts(struct seq_file *m, struct super_block *sb) static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) { - static const struct proc_fs_info mnt_info[] = { + static const struct proc_fs_opts mnt_opts[] = { { MNT_NOSUID, ",nosuid" }, { MNT_NODEV, ",nodev" }, { MNT_NOEXEC, ",noexec" }, @@ -72,9 +72,9 @@ static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) { MNT_RELATIME, ",relatime" }, { 0, NULL } }; - const struct proc_fs_info *fs_infop; + const struct proc_fs_opts *fs_infop; - for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) { + for (fs_infop = mnt_opts; fs_infop->flag; fs_infop++) { if (mnt->mnt_flags & fs_infop->flag) seq_puts(m, fs_infop->str); } From patchwork Fri Mar 27 17:23:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Gladkov X-Patchwork-Id: 11462829 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 0D72B1667 for ; Fri, 27 Mar 2020 17:32:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E05CD208E4 for ; Fri, 27 Mar 2020 17:32:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727806AbgC0Rbx (ORCPT ); Fri, 27 Mar 2020 13:31:53 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:38856 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727742AbgC0Rbt (ORCPT ); Fri, 27 Mar 2020 13:31:49 -0400 Received: from comp-core-i7-2640m-0182e6.redhat.com (ip-89-102-33-211.net.upcbroadband.cz [89.102.33.211]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by raptor.unsafe.ru (Postfix) with ESMTPSA id 854FA20AA9; Fri, 27 Mar 2020 17:23:56 +0000 (UTC) From: Alexey Gladkov To: LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module Cc: Akinobu Mita , Alexander Viro , Alexey Dobriyan , Alexey Gladkov , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , "Eric W . Biederman" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Linus Torvalds , Oleg Nesterov Subject: [PATCH v10 2/9] proc: allow to mount many instances of proc in one pid namespace Date: Fri, 27 Mar 2020 18:23:24 +0100 Message-Id: <20200327172331.418878-3-gladkov.alexey@gmail.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200327172331.418878-1-gladkov.alexey@gmail.com> References: <20200327172331.418878-1-gladkov.alexey@gmail.com> MIME-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.1 (raptor.unsafe.ru [5.9.43.93]); Fri, 27 Mar 2020 17:23:57 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This patch allows to have multiple procfs instances inside the same pid namespace. The aim here is lightweight sandboxes, and to allow that we have to modernize procfs internals. 1) The main aim of this work is to have on embedded systems one supervisor for apps. Right now we have some lightweight sandbox support, however if we create pid namespacess we have to manages all the processes inside too, where our goal is to be able to run a bunch of apps each one inside its own mount namespace without being able to notice each other. We only want to use mount namespaces, and we want procfs to behave more like a real mount point. 2) Linux Security Modules have multiple ptrace paths inside some subsystems, however inside procfs, the implementation does not guarantee that the ptrace() check which triggers the security_ptrace_check() hook will always run. We have the 'hidepid' mount option that can be used to force the ptrace_may_access() check inside has_pid_permissions() to run. The problem is that 'hidepid' is per pid namespace and not attached to the mount point, any remount or modification of 'hidepid' will propagate to all other procfs mounts. This also does not allow to support Yama LSM easily in desktop and user sessions. Yama ptrace scope which restricts ptrace and some other syscalls to be allowed only on inferiors, can be updated to have a per-task context, where the context will be inherited during fork(), clone() and preserved across execve(). If we support multiple private procfs instances, then we may force the ptrace_may_access() on /proc// to always run inside that new procfs instances. This will allow to specifiy on user sessions if we should populate procfs with pids that the user can ptrace or not. By using Yama ptrace scope, some restricted users will only be able to see inferiors inside /proc, they won't even be able to see their other processes. Some software like Chromium, Firefox's crash handler, Wine and others are already using Yama to restrict which processes can be ptracable. With this change this will give the possibility to restrict /proc// but more importantly this will give desktop users a generic and usuable way to specifiy which users should see all processes and which users can not. Side notes: * This covers the lack of seccomp where it is not able to parse arguments, it is easy to install a seccomp filter on direct syscalls that operate on pids, however /proc// is a Linux ABI using filesystem syscalls. With this change LSMs should be able to analyze open/read/write/close... In the new patchset version I removed the 'newinstance' option as suggested by Eric W. Biederman. Reviewed-by: Alexey Dobriyan Signed-off-by: Alexey Gladkov --- fs/proc/base.c | 13 +++++++++---- fs/proc/inode.c | 4 ++-- fs/proc/root.c | 42 +++++++++++++++++++++++++---------------- fs/proc/self.c | 6 +++--- fs/proc/thread_self.c | 6 +++--- include/linux/proc_fs.h | 12 ++++++++++++ 6 files changed, 55 insertions(+), 28 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 74f948a6b621..3b9155a69ade 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3301,6 +3301,7 @@ struct dentry *proc_pid_lookup(struct dentry *dentry, unsigned int flags) { struct task_struct *task; unsigned tgid; + struct proc_fs_info *fs_info; struct pid_namespace *ns; struct dentry *result = ERR_PTR(-ENOENT); @@ -3308,7 +3309,8 @@ struct dentry *proc_pid_lookup(struct dentry *dentry, unsigned int flags) if (tgid == ~0U) goto out; - ns = dentry->d_sb->s_fs_info; + fs_info = proc_sb_info(dentry->d_sb); + ns = fs_info->pid_ns; rcu_read_lock(); task = find_task_by_pid_ns(tgid, ns); if (task) @@ -3372,6 +3374,7 @@ static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter ite int proc_pid_readdir(struct file *file, struct dir_context *ctx) { struct tgid_iter iter; + struct proc_fs_info *fs_info = proc_sb_info(file_inode(file)->i_sb); struct pid_namespace *ns = proc_pid_ns(file_inode(file)); loff_t pos = ctx->pos; @@ -3379,13 +3382,13 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx) return 0; if (pos == TGID_OFFSET - 2) { - struct inode *inode = d_inode(ns->proc_self); + struct inode *inode = d_inode(fs_info->proc_self); if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK)) return 0; ctx->pos = pos = pos + 1; } if (pos == TGID_OFFSET - 1) { - struct inode *inode = d_inode(ns->proc_thread_self); + struct inode *inode = d_inode(fs_info->proc_thread_self); if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK)) return 0; ctx->pos = pos = pos + 1; @@ -3599,6 +3602,7 @@ static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry struct task_struct *task; struct task_struct *leader = get_proc_task(dir); unsigned tid; + struct proc_fs_info *fs_info; struct pid_namespace *ns; struct dentry *result = ERR_PTR(-ENOENT); @@ -3609,7 +3613,8 @@ static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry if (tid == ~0U) goto out; - ns = dentry->d_sb->s_fs_info; + fs_info = proc_sb_info(dentry->d_sb); + ns = fs_info->pid_ns; rcu_read_lock(); task = find_task_by_pid_ns(tid, ns); if (task) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 1e730ea1dcd6..6e4c6728338b 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -167,8 +167,8 @@ void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock static int proc_show_options(struct seq_file *seq, struct dentry *root) { - struct super_block *sb = root->d_sb; - struct pid_namespace *pid = sb->s_fs_info; + struct proc_fs_info *fs_info = proc_sb_info(root->d_sb); + struct pid_namespace *pid = fs_info->pid_ns; if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID)) seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid)); diff --git a/fs/proc/root.c b/fs/proc/root.c index 2633f10446c3..b28adbb0b937 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -30,7 +30,7 @@ #include "internal.h" struct proc_fs_context { - struct pid_namespace *pid_ns; + struct proc_fs_info *fs_info; unsigned int mask; int hidepid; int gid; @@ -92,7 +92,8 @@ static void proc_apply_options(struct super_block *s, static int proc_fill_super(struct super_block *s, struct fs_context *fc) { - struct pid_namespace *pid_ns = get_pid_ns(s->s_fs_info); + struct proc_fs_context *ctx = fc->fs_private; + struct pid_namespace *pid_ns = get_pid_ns(ctx->fs_info->pid_ns); struct inode *root_inode; int ret; @@ -106,6 +107,7 @@ static int proc_fill_super(struct super_block *s, struct fs_context *fc) s->s_magic = PROC_SUPER_MAGIC; s->s_op = &proc_sops; s->s_time_gran = 1; + s->s_fs_info = ctx->fs_info; /* * procfs isn't actually a stacking filesystem; however, there is @@ -113,7 +115,7 @@ static int proc_fill_super(struct super_block *s, struct fs_context *fc) * top of it */ s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH; - + /* procfs dentries and inodes don't require IO to create */ s->s_shrink.seeks = 0; @@ -140,7 +142,8 @@ static int proc_fill_super(struct super_block *s, struct fs_context *fc) static int proc_reconfigure(struct fs_context *fc) { struct super_block *sb = fc->root->d_sb; - struct pid_namespace *pid = sb->s_fs_info; + struct proc_fs_info *fs_info = proc_sb_info(sb); + struct pid_namespace *pid = fs_info->pid_ns; sync_filesystem(sb); @@ -150,16 +153,14 @@ static int proc_reconfigure(struct fs_context *fc) static int proc_get_tree(struct fs_context *fc) { - struct proc_fs_context *ctx = fc->fs_private; - - return get_tree_keyed(fc, proc_fill_super, ctx->pid_ns); + return get_tree_nodev(fc, proc_fill_super); } static void proc_fs_context_free(struct fs_context *fc) { struct proc_fs_context *ctx = fc->fs_private; - put_pid_ns(ctx->pid_ns); + put_pid_ns(ctx->fs_info->pid_ns); kfree(ctx); } @@ -178,9 +179,15 @@ static int proc_init_fs_context(struct fs_context *fc) if (!ctx) return -ENOMEM; - ctx->pid_ns = get_pid_ns(task_active_pid_ns(current)); + ctx->fs_info = kzalloc(sizeof(struct proc_fs_info), GFP_KERNEL); + if (!ctx->fs_info) { + kfree(ctx); + return -ENOMEM; + } + + ctx->fs_info->pid_ns = get_pid_ns(task_active_pid_ns(current)); put_user_ns(fc->user_ns); - fc->user_ns = get_user_ns(ctx->pid_ns->user_ns); + fc->user_ns = get_user_ns(ctx->fs_info->pid_ns->user_ns); fc->fs_private = ctx; fc->ops = &proc_fs_context_ops; return 0; @@ -188,15 +195,18 @@ static int proc_init_fs_context(struct fs_context *fc) static void proc_kill_sb(struct super_block *sb) { - struct pid_namespace *ns; + struct proc_fs_info *fs_info = proc_sb_info(sb); + struct pid_namespace *ns = fs_info->pid_ns; + + if (fs_info->proc_self) + dput(fs_info->proc_self); + + if (fs_info->proc_thread_self) + dput(fs_info->proc_thread_self); - ns = (struct pid_namespace *)sb->s_fs_info; - if (ns->proc_self) - dput(ns->proc_self); - if (ns->proc_thread_self) - dput(ns->proc_thread_self); kill_anon_super(sb); put_pid_ns(ns); + kfree(fs_info); } static struct file_system_type proc_fs_type = { diff --git a/fs/proc/self.c b/fs/proc/self.c index 57c0a1047250..309301ac0136 100644 --- a/fs/proc/self.c +++ b/fs/proc/self.c @@ -36,10 +36,10 @@ static unsigned self_inum __ro_after_init; int proc_setup_self(struct super_block *s) { struct inode *root_inode = d_inode(s->s_root); - struct pid_namespace *ns = proc_pid_ns(root_inode); + struct proc_fs_info *fs_info = proc_sb_info(s); struct dentry *self; int ret = -ENOMEM; - + inode_lock(root_inode); self = d_alloc_name(s->s_root, "self"); if (self) { @@ -62,7 +62,7 @@ int proc_setup_self(struct super_block *s) if (ret) pr_err("proc_fill_super: can't allocate /proc/self\n"); else - ns->proc_self = self; + fs_info->proc_self = self; return ret; } diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c index f61ae53533f5..2493cbbdfa6f 100644 --- a/fs/proc/thread_self.c +++ b/fs/proc/thread_self.c @@ -36,7 +36,7 @@ static unsigned thread_self_inum __ro_after_init; int proc_setup_thread_self(struct super_block *s) { struct inode *root_inode = d_inode(s->s_root); - struct pid_namespace *ns = proc_pid_ns(root_inode); + struct proc_fs_info *fs_info = proc_sb_info(s); struct dentry *thread_self; int ret = -ENOMEM; @@ -60,9 +60,9 @@ int proc_setup_thread_self(struct super_block *s) inode_unlock(root_inode); if (ret) - pr_err("proc_fill_super: can't allocate /proc/thread_self\n"); + pr_err("proc_fill_super: can't allocate /proc/thread-self\n"); else - ns->proc_thread_self = thread_self; + fs_info->proc_thread_self = thread_self; return ret; } diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 40a7982b7285..5920a4ecd71b 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -27,6 +27,17 @@ struct proc_ops { unsigned long (*proc_get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); }; +struct proc_fs_info { + struct pid_namespace *pid_ns; + struct dentry *proc_self; /* For /proc/self */ + struct dentry *proc_thread_self; /* For /proc/thread-self */ +}; + +static inline struct proc_fs_info *proc_sb_info(struct super_block *sb) +{ + return sb->s_fs_info; +} + #ifdef CONFIG_PROC_FS typedef int (*proc_write_t)(struct file *, char *, size_t); @@ -161,6 +172,7 @@ int open_related_ns(struct ns_common *ns, /* get the associated pid namespace for a file in procfs */ static inline struct pid_namespace *proc_pid_ns(const struct inode *inode) { + return proc_sb_info(inode->i_sb)->pid_ns; return inode->i_sb->s_fs_info; } From patchwork Fri Mar 27 17:23:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Gladkov X-Patchwork-Id: 11462837 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 5C32913A4 for ; Fri, 27 Mar 2020 17:32:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3B82220848 for ; Fri, 27 Mar 2020 17:32:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727875AbgC0RcJ (ORCPT ); Fri, 27 Mar 2020 13:32:09 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:38848 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726275AbgC0Rbr (ORCPT ); Fri, 27 Mar 2020 13:31:47 -0400 Received: from comp-core-i7-2640m-0182e6.redhat.com (ip-89-102-33-211.net.upcbroadband.cz [89.102.33.211]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by raptor.unsafe.ru (Postfix) with ESMTPSA id A141C20AAC; Fri, 27 Mar 2020 17:23:57 +0000 (UTC) From: Alexey Gladkov To: LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module Cc: Akinobu Mita , Alexander Viro , Alexey Dobriyan , Alexey Gladkov , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , "Eric W . Biederman" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Linus Torvalds , Oleg Nesterov Subject: [PATCH v10 3/9] proc: move hide_pid, pid_gid from pid_namespace to proc_fs_info Date: Fri, 27 Mar 2020 18:23:25 +0100 Message-Id: <20200327172331.418878-4-gladkov.alexey@gmail.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200327172331.418878-1-gladkov.alexey@gmail.com> References: <20200327172331.418878-1-gladkov.alexey@gmail.com> MIME-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.1 (raptor.unsafe.ru [5.9.43.93]); Fri, 27 Mar 2020 17:23:58 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Move hide_pid and pid_gid parameters inside procfs fs_info struct instead of making them per pid namespace. Since we have a multiple procfs instances per pid namespace we need to make sure that all proc-specific parameters are also per-superblock. Reviewed-by: Alexey Dobriyan Signed-off-by: Alexey Gladkov --- fs/proc/base.c | 18 +++++++++--------- fs/proc/inode.c | 9 ++++----- fs/proc/root.c | 4 ++-- include/linux/pid_namespace.h | 8 -------- include/linux/proc_fs.h | 9 +++++++++ 5 files changed, 24 insertions(+), 24 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 3b9155a69ade..43a28907baf9 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -697,13 +697,13 @@ int proc_setattr(struct dentry *dentry, struct iattr *attr) * May current process learn task's sched/cmdline info (for hide_pid_min=1) * or euid/egid (for hide_pid_min=2)? */ -static bool has_pid_permissions(struct pid_namespace *pid, +static bool has_pid_permissions(struct proc_fs_info *fs_info, struct task_struct *task, int hide_pid_min) { - if (pid->hide_pid < hide_pid_min) + if (fs_info->hide_pid < hide_pid_min) return true; - if (in_group_p(pid->pid_gid)) + if (in_group_p(fs_info->pid_gid)) return true; return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS); } @@ -711,18 +711,18 @@ static bool has_pid_permissions(struct pid_namespace *pid, static int proc_pid_permission(struct inode *inode, int mask) { - struct pid_namespace *pid = proc_pid_ns(inode); + struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb); struct task_struct *task; bool has_perms; task = get_proc_task(inode); if (!task) return -ESRCH; - has_perms = has_pid_permissions(pid, task, HIDEPID_NO_ACCESS); + has_perms = has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS); put_task_struct(task); if (!has_perms) { - if (pid->hide_pid == HIDEPID_INVISIBLE) { + if (fs_info->hide_pid == HIDEPID_INVISIBLE) { /* * Let's make getdents(), stat(), and open() * consistent with each other. If a process @@ -1897,7 +1897,7 @@ int pid_getattr(const struct path *path, struct kstat *stat, u32 request_mask, unsigned int query_flags) { struct inode *inode = d_inode(path->dentry); - struct pid_namespace *pid = proc_pid_ns(inode); + struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb); struct task_struct *task; generic_fillattr(inode, stat); @@ -1907,7 +1907,7 @@ int pid_getattr(const struct path *path, struct kstat *stat, rcu_read_lock(); task = pid_task(proc_pid(inode), PIDTYPE_PID); if (task) { - if (!has_pid_permissions(pid, task, HIDEPID_INVISIBLE)) { + if (!has_pid_permissions(fs_info, task, HIDEPID_INVISIBLE)) { rcu_read_unlock(); /* * This doesn't prevent learning whether PID exists, @@ -3402,7 +3402,7 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx) unsigned int len; cond_resched(); - if (!has_pid_permissions(ns, iter.task, HIDEPID_INVISIBLE)) + if (!has_pid_permissions(fs_info, iter.task, HIDEPID_INVISIBLE)) continue; len = snprintf(name, sizeof(name), "%u", iter.tgid); diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 6e4c6728338b..91fe4896fa85 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -168,12 +168,11 @@ void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock static int proc_show_options(struct seq_file *seq, struct dentry *root) { struct proc_fs_info *fs_info = proc_sb_info(root->d_sb); - struct pid_namespace *pid = fs_info->pid_ns; - if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID)) - seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid)); - if (pid->hide_pid != HIDEPID_OFF) - seq_printf(seq, ",hidepid=%u", pid->hide_pid); + if (!gid_eq(fs_info->pid_gid, GLOBAL_ROOT_GID)) + seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid)); + if (fs_info->hide_pid != HIDEPID_OFF) + seq_printf(seq, ",hidepid=%u", fs_info->hide_pid); return 0; } diff --git a/fs/proc/root.c b/fs/proc/root.c index b28adbb0b937..616e8976185c 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -85,9 +85,9 @@ static void proc_apply_options(struct super_block *s, struct proc_fs_context *ctx = fc->fs_private; if (ctx->mask & (1 << Opt_gid)) - pid_ns->pid_gid = make_kgid(user_ns, ctx->gid); + ctx->fs_info->pid_gid = make_kgid(user_ns, ctx->gid); if (ctx->mask & (1 << Opt_hidepid)) - pid_ns->hide_pid = ctx->hidepid; + ctx->fs_info->hide_pid = ctx->hidepid; } static int proc_fill_super(struct super_block *s, struct fs_context *fc) diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h index 4956e362e55e..028d7ba242c6 100644 --- a/include/linux/pid_namespace.h +++ b/include/linux/pid_namespace.h @@ -17,12 +17,6 @@ struct fs_pin; -enum { /* definitions for pid_namespace's hide_pid field */ - HIDEPID_OFF = 0, - HIDEPID_NO_ACCESS = 1, - HIDEPID_INVISIBLE = 2, -}; - struct pid_namespace { struct kref kref; struct idr idr; @@ -41,8 +35,6 @@ struct pid_namespace { #endif struct user_namespace *user_ns; struct ucounts *ucounts; - kgid_t pid_gid; - int hide_pid; int reboot; /* group exit code if this pidns was rebooted */ struct ns_common ns; } __randomize_layout; diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 5920a4ecd71b..7d852dbca253 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -27,10 +27,19 @@ struct proc_ops { unsigned long (*proc_get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); }; +/* definitions for hide_pid field */ +enum { + HIDEPID_OFF = 0, + HIDEPID_NO_ACCESS = 1, + HIDEPID_INVISIBLE = 2, +}; + struct proc_fs_info { struct pid_namespace *pid_ns; struct dentry *proc_self; /* For /proc/self */ struct dentry *proc_thread_self; /* For /proc/thread-self */ + kgid_t pid_gid; + int hide_pid; }; static inline struct proc_fs_info *proc_sb_info(struct super_block *sb) From patchwork Fri Mar 27 17:23:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Gladkov X-Patchwork-Id: 11462847 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 DB6D51392 for ; Fri, 27 Mar 2020 17:32:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C560020774 for ; Fri, 27 Mar 2020 17:32:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727719AbgC0Rbo (ORCPT ); Fri, 27 Mar 2020 13:31:44 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:38826 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727509AbgC0Rbn (ORCPT ); Fri, 27 Mar 2020 13:31:43 -0400 Received: from comp-core-i7-2640m-0182e6.redhat.com (ip-89-102-33-211.net.upcbroadband.cz [89.102.33.211]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by raptor.unsafe.ru (Postfix) with ESMTPSA id 60FDC20AAE; Fri, 27 Mar 2020 17:23:58 +0000 (UTC) From: Alexey Gladkov To: LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module Cc: Akinobu Mita , Alexander Viro , Alexey Dobriyan , Alexey Gladkov , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , "Eric W . Biederman" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Linus Torvalds , Oleg Nesterov Subject: [PATCH v10 4/9] proc: instantiate only pids that we can ptrace on 'hidepid=4' mount option Date: Fri, 27 Mar 2020 18:23:26 +0100 Message-Id: <20200327172331.418878-5-gladkov.alexey@gmail.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200327172331.418878-1-gladkov.alexey@gmail.com> References: <20200327172331.418878-1-gladkov.alexey@gmail.com> MIME-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.1 (raptor.unsafe.ru [5.9.43.93]); Fri, 27 Mar 2020 17:23:59 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org If "hidepid=4" mount option is set then do not instantiate pids that we can not ptrace. "hidepid=4" means that procfs should only contain pids that the caller can ptrace. Cc: Kees Cook Cc: Andy Lutomirski Signed-off-by: Djalal Harouni Reviewed-by: Alexey Dobriyan Signed-off-by: Alexey Gladkov --- fs/proc/base.c | 15 +++++++++++++++ fs/proc/root.c | 13 ++++++++++--- include/linux/proc_fs.h | 1 + 3 files changed, 26 insertions(+), 3 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 43a28907baf9..1ebe9eba48ea 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -701,6 +701,14 @@ static bool has_pid_permissions(struct proc_fs_info *fs_info, struct task_struct *task, int hide_pid_min) { + /* + * If 'hidpid' mount option is set force a ptrace check, + * we indicate that we are using a filesystem syscall + * by passing PTRACE_MODE_READ_FSCREDS + */ + if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE) + return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS); + if (fs_info->hide_pid < hide_pid_min) return true; if (in_group_p(fs_info->pid_gid)) @@ -3319,7 +3327,14 @@ struct dentry *proc_pid_lookup(struct dentry *dentry, unsigned int flags) if (!task) goto out; + /* Limit procfs to only ptraceable tasks */ + if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE) { + if (!has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS)) + goto out_put_task; + } + result = proc_pid_instantiate(dentry, task, NULL); +out_put_task: put_task_struct(task); out: return result; diff --git a/fs/proc/root.c b/fs/proc/root.c index 616e8976185c..62eae22403d2 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -47,6 +47,14 @@ static const struct fs_parameter_spec proc_fs_parameters[] = { {} }; +static inline int valid_hidepid(unsigned int value) +{ + return (value == HIDEPID_OFF || + value == HIDEPID_NO_ACCESS || + value == HIDEPID_INVISIBLE || + value == HIDEPID_NOT_PTRACEABLE); +} + static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param) { struct proc_fs_context *ctx = fc->fs_private; @@ -63,10 +71,9 @@ static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param) break; case Opt_hidepid: + if (!valid_hidepid(result.uint_32)) + return invalf(fc, "proc: unknown value of hidepid.\n"); ctx->hidepid = result.uint_32; - if (ctx->hidepid < HIDEPID_OFF || - ctx->hidepid > HIDEPID_INVISIBLE) - return invalfc(fc, "hidepid value must be between 0 and 2.\n"); break; default: diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 7d852dbca253..21d19353fdc7 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -32,6 +32,7 @@ enum { HIDEPID_OFF = 0, HIDEPID_NO_ACCESS = 1, HIDEPID_INVISIBLE = 2, + HIDEPID_NOT_PTRACEABLE = 4, /* Limit pids to only ptraceable pids */ }; struct proc_fs_info { From patchwork Fri Mar 27 17:23:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Gladkov X-Patchwork-Id: 11462843 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 59D6B13A4 for ; Fri, 27 Mar 2020 17:32:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 38D0321556 for ; Fri, 27 Mar 2020 17:32:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727888AbgC0RcP (ORCPT ); Fri, 27 Mar 2020 13:32:15 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:38830 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727585AbgC0Rbo (ORCPT ); Fri, 27 Mar 2020 13:31:44 -0400 Received: from comp-core-i7-2640m-0182e6.redhat.com (ip-89-102-33-211.net.upcbroadband.cz [89.102.33.211]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by raptor.unsafe.ru (Postfix) with ESMTPSA id 2613120AB0; Fri, 27 Mar 2020 17:23:59 +0000 (UTC) From: Alexey Gladkov To: LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module Cc: Akinobu Mita , Alexander Viro , Alexey Dobriyan , Alexey Gladkov , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , "Eric W . Biederman" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Linus Torvalds , Oleg Nesterov Subject: [PATCH v10 5/9] proc: add option to mount only a pids subset Date: Fri, 27 Mar 2020 18:23:27 +0100 Message-Id: <20200327172331.418878-6-gladkov.alexey@gmail.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200327172331.418878-1-gladkov.alexey@gmail.com> References: <20200327172331.418878-1-gladkov.alexey@gmail.com> MIME-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.1 (raptor.unsafe.ru [5.9.43.93]); Fri, 27 Mar 2020 17:23:59 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This allows to hide all files and directories in the procfs that are not related to tasks. Reviewed-by: Alexey Dobriyan Signed-off-by: Alexey Gladkov --- fs/proc/generic.c | 9 +++++++++ fs/proc/inode.c | 6 ++++++ fs/proc/root.c | 33 +++++++++++++++++++++++++++++++++ include/linux/proc_fs.h | 7 +++++++ 4 files changed, 55 insertions(+) diff --git a/fs/proc/generic.c b/fs/proc/generic.c index 3faed94e4b65..ee5b6482009c 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -269,6 +269,11 @@ struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry, struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { + struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb); + + if (fs_info->pidonly == PROC_PIDONLY_ON) + return ERR_PTR(-ENOENT); + return proc_lookup_de(dir, dentry, PDE(dir)); } @@ -325,6 +330,10 @@ int proc_readdir_de(struct file *file, struct dir_context *ctx, int proc_readdir(struct file *file, struct dir_context *ctx) { struct inode *inode = file_inode(file); + struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb); + + if (fs_info->pidonly == PROC_PIDONLY_ON) + return 1; return proc_readdir_de(file, ctx, PDE(inode)); } diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 91fe4896fa85..e6577ce6027b 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -173,6 +173,8 @@ static int proc_show_options(struct seq_file *seq, struct dentry *root) seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid)); if (fs_info->hide_pid != HIDEPID_OFF) seq_printf(seq, ",hidepid=%u", fs_info->hide_pid); + if (fs_info->pidonly != PROC_PIDONLY_OFF) + seq_printf(seq, ",subset=pid"); return 0; } @@ -393,12 +395,16 @@ proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr, static int proc_reg_open(struct inode *inode, struct file *file) { + struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb); struct proc_dir_entry *pde = PDE(inode); int rv = 0; typeof_member(struct proc_ops, proc_open) open; typeof_member(struct proc_ops, proc_release) release; struct pde_opener *pdeo; + if (fs_info->pidonly == PROC_PIDONLY_ON) + return -ENOENT; + /* * Ensure that * 1) PDE's ->release hook will be called no matter what diff --git a/fs/proc/root.c b/fs/proc/root.c index 62eae22403d2..dbcd96f07c7a 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -34,16 +34,19 @@ struct proc_fs_context { unsigned int mask; int hidepid; int gid; + int pidonly; }; enum proc_param { Opt_gid, Opt_hidepid, + Opt_subset, }; static const struct fs_parameter_spec proc_fs_parameters[] = { fsparam_u32("gid", Opt_gid), fsparam_u32("hidepid", Opt_hidepid), + fsparam_string("subset", Opt_subset), {} }; @@ -55,6 +58,29 @@ static inline int valid_hidepid(unsigned int value) value == HIDEPID_NOT_PTRACEABLE); } +static int proc_parse_subset_param(struct fs_context *fc, char *value) +{ + struct proc_fs_context *ctx = fc->fs_private; + + while (value) { + char *ptr = strchr(value, ','); + + if (ptr != NULL) + *ptr++ = '\0'; + + if (*value != '\0') { + if (!strcmp(value, "pid")) { + ctx->pidonly = PROC_PIDONLY_ON; + } else { + return invalf(fc, "proc: unsupported subset option - %s\n", value); + } + } + value = ptr; + } + + return 0; +} + static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param) { struct proc_fs_context *ctx = fc->fs_private; @@ -76,6 +102,11 @@ static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param) ctx->hidepid = result.uint_32; break; + case Opt_subset: + if (proc_parse_subset_param(fc, param->string) < 0) + return -EINVAL; + break; + default: return -EINVAL; } @@ -95,6 +126,8 @@ static void proc_apply_options(struct super_block *s, ctx->fs_info->pid_gid = make_kgid(user_ns, ctx->gid); if (ctx->mask & (1 << Opt_hidepid)) ctx->fs_info->hide_pid = ctx->hidepid; + if (ctx->mask & (1 << Opt_subset)) + ctx->fs_info->pidonly = ctx->pidonly; } static int proc_fill_super(struct super_block *s, struct fs_context *fc) diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 21d19353fdc7..afd38cae2339 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -35,12 +35,19 @@ enum { HIDEPID_NOT_PTRACEABLE = 4, /* Limit pids to only ptraceable pids */ }; +/* definitions for proc mount option pidonly */ +enum { + PROC_PIDONLY_OFF = 0, + PROC_PIDONLY_ON = 1, +}; + struct proc_fs_info { struct pid_namespace *pid_ns; struct dentry *proc_self; /* For /proc/self */ struct dentry *proc_thread_self; /* For /proc/thread-self */ kgid_t pid_gid; int hide_pid; + int pidonly; }; static inline struct proc_fs_info *proc_sb_info(struct super_block *sb) From patchwork Fri Mar 27 17:23:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Gladkov X-Patchwork-Id: 11462821 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 4C69813A4 for ; Fri, 27 Mar 2020 17:31:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 34D5820848 for ; Fri, 27 Mar 2020 17:31:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727841AbgC0Rbx (ORCPT ); Fri, 27 Mar 2020 13:31:53 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:38852 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727749AbgC0Rbt (ORCPT ); Fri, 27 Mar 2020 13:31:49 -0400 Received: from comp-core-i7-2640m-0182e6.redhat.com (ip-89-102-33-211.net.upcbroadband.cz [89.102.33.211]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by raptor.unsafe.ru (Postfix) with ESMTPSA id E38B920AB2; Fri, 27 Mar 2020 17:23:59 +0000 (UTC) From: Alexey Gladkov To: LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module Cc: Akinobu Mita , Alexander Viro , Alexey Dobriyan , Alexey Gladkov , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , "Eric W . Biederman" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Linus Torvalds , Oleg Nesterov Subject: [PATCH v10 6/9] docs: proc: add documentation for "hidepid=4" and "subset=pid" options and new mount behavior Date: Fri, 27 Mar 2020 18:23:28 +0100 Message-Id: <20200327172331.418878-7-gladkov.alexey@gmail.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200327172331.418878-1-gladkov.alexey@gmail.com> References: <20200327172331.418878-1-gladkov.alexey@gmail.com> MIME-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.1 (raptor.unsafe.ru [5.9.43.93]); Fri, 27 Mar 2020 17:24:00 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Reviewed-by: Alexey Dobriyan Signed-off-by: Alexey Gladkov --- Documentation/filesystems/proc.txt | 53 ++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 99ca040e3f90..bd0e0ab85048 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -50,6 +50,8 @@ Table of Contents 4 Configuring procfs 4.1 Mount options + 5 Filesystem behavior + ------------------------------------------------------------------------------ Preface ------------------------------------------------------------------------------ @@ -2021,6 +2023,7 @@ The following mount options are supported: hidepid= Set /proc// access mode. gid= Set the group authorized to learn processes information. + subset= Show only the specified subset of procfs. hidepid=0 means classic mode - everybody may access all /proc// directories (default). @@ -2042,6 +2045,56 @@ information about running processes, whether some daemon runs with elevated privileges, whether other user runs some sensitive program, whether other users run any program at all, etc. +hidepid=4 means that procfs should only contain /proc// directories +that the caller can ptrace. + gid= defines a group authorized to learn processes information otherwise prohibited by hidepid=. If you use some daemon like identd which needs to learn information about processes information, just add identd to this group. + +subset=pid hides all top level files and directories in the procfs that +are not related to tasks. + +------------------------------------------------------------------------------ +5 Filesystem behavior +------------------------------------------------------------------------------ + +Originally, before the advent of pid namepsace, procfs was a global file +system. It means that there was only one procfs instance in the system. + +When pid namespace was added, a separate procfs instance was mounted in +each pid namespace. So, procfs mount options are global among all +mountpoints within the same namespace. + +# grep ^proc /proc/mounts +proc /proc proc rw,relatime,hidepid=2 0 0 + +# strace -e mount mount -o hidepid=1 -t proc proc /tmp/proc +mount("proc", "/tmp/proc", "proc", 0, "hidepid=1") = 0 ++++ exited with 0 +++ + +# grep ^proc /proc/mounts +proc /proc proc rw,relatime,hidepid=2 0 0 +proc /tmp/proc proc rw,relatime,hidepid=2 0 0 + +and only after remounting procfs mount options will change at all +mountpoints. + +# mount -o remount,hidepid=1 -t proc proc /tmp/proc + +# grep ^proc /proc/mounts +proc /proc proc rw,relatime,hidepid=1 0 0 +proc /tmp/proc proc rw,relatime,hidepid=1 0 0 + +This behavior is different from the behavior of other filesystems. + +The new procfs behavior is more like other filesystems. Each procfs mount +creates a new procfs instance. Mount options affect own procfs instance. +It means that it became possible to have several procfs instances +displaying tasks with different filtering options in one pid namespace. + +# mount -o hidepid=2 -t proc proc /proc +# mount -o hidepid=1 -t proc proc /tmp/proc +# grep ^proc /proc/mounts +proc /proc proc rw,relatime,hidepid=2 0 0 +proc /tmp/proc proc rw,relatime,hidepid=1 0 0 From patchwork Fri Mar 27 17:23:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Gladkov X-Patchwork-Id: 11462819 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 C976613A4 for ; Fri, 27 Mar 2020 17:31:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B218A2073B for ; Fri, 27 Mar 2020 17:31:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727801AbgC0Rbt (ORCPT ); Fri, 27 Mar 2020 13:31:49 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:38850 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727770AbgC0Rbs (ORCPT ); Fri, 27 Mar 2020 13:31:48 -0400 Received: from comp-core-i7-2640m-0182e6.redhat.com (ip-89-102-33-211.net.upcbroadband.cz [89.102.33.211]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by raptor.unsafe.ru (Postfix) with ESMTPSA id A172520AB4; Fri, 27 Mar 2020 17:24:00 +0000 (UTC) From: Alexey Gladkov To: LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module Cc: Akinobu Mita , Alexander Viro , Alexey Dobriyan , Alexey Gladkov , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , "Eric W . Biederman" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Linus Torvalds , Oleg Nesterov Subject: [PATCH v10 7/9] proc: move hidepid values to uapi as they are user interface to mount Date: Fri, 27 Mar 2020 18:23:29 +0100 Message-Id: <20200327172331.418878-8-gladkov.alexey@gmail.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200327172331.418878-1-gladkov.alexey@gmail.com> References: <20200327172331.418878-1-gladkov.alexey@gmail.com> MIME-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.1 (raptor.unsafe.ru [5.9.43.93]); Fri, 27 Mar 2020 17:24:01 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Suggested-by: Alexey Dobriyan Reviewed-by: Alexey Dobriyan Signed-off-by: Alexey Gladkov --- include/linux/proc_fs.h | 9 +-------- include/uapi/linux/proc_fs.h | 13 +++++++++++++ 2 files changed, 14 insertions(+), 8 deletions(-) create mode 100644 include/uapi/linux/proc_fs.h diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index afd38cae2339..d259817ec913 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -7,6 +7,7 @@ #include #include +#include struct proc_dir_entry; struct seq_file; @@ -27,14 +28,6 @@ struct proc_ops { unsigned long (*proc_get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); }; -/* definitions for hide_pid field */ -enum { - HIDEPID_OFF = 0, - HIDEPID_NO_ACCESS = 1, - HIDEPID_INVISIBLE = 2, - HIDEPID_NOT_PTRACEABLE = 4, /* Limit pids to only ptraceable pids */ -}; - /* definitions for proc mount option pidonly */ enum { PROC_PIDONLY_OFF = 0, diff --git a/include/uapi/linux/proc_fs.h b/include/uapi/linux/proc_fs.h new file mode 100644 index 000000000000..dc6d717aa6ec --- /dev/null +++ b/include/uapi/linux/proc_fs.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _UAPI_PROC_FS_H +#define _UAPI_PROC_FS_H + +/* definitions for hide_pid field */ +enum { + HIDEPID_OFF = 0, + HIDEPID_NO_ACCESS = 1, + HIDEPID_INVISIBLE = 2, + HIDEPID_NOT_PTRACEABLE = 4, +}; + +#endif From patchwork Fri Mar 27 17:23:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Gladkov X-Patchwork-Id: 11462817 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 343AA1392 for ; Fri, 27 Mar 2020 17:31:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1386B2073B for ; Fri, 27 Mar 2020 17:31:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727774AbgC0Rbp (ORCPT ); Fri, 27 Mar 2020 13:31:45 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:38822 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726738AbgC0Rbp (ORCPT ); Fri, 27 Mar 2020 13:31:45 -0400 Received: from comp-core-i7-2640m-0182e6.redhat.com (ip-89-102-33-211.net.upcbroadband.cz [89.102.33.211]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by raptor.unsafe.ru (Postfix) with ESMTPSA id 63CD020AB6; Fri, 27 Mar 2020 17:24:01 +0000 (UTC) From: Alexey Gladkov To: LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module Cc: Akinobu Mita , Alexander Viro , Alexey Dobriyan , Alexey Gladkov , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , "Eric W . Biederman" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Linus Torvalds , Oleg Nesterov Subject: [PATCH v10 8/9] proc: use human-readable values for hidehid Date: Fri, 27 Mar 2020 18:23:30 +0100 Message-Id: <20200327172331.418878-9-gladkov.alexey@gmail.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200327172331.418878-1-gladkov.alexey@gmail.com> References: <20200327172331.418878-1-gladkov.alexey@gmail.com> MIME-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.1 (raptor.unsafe.ru [5.9.43.93]); Fri, 27 Mar 2020 17:24:02 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The hidepid parameter values are becoming more and more and it becomes difficult to remember what each new magic number means. Suggested-by: Andy Lutomirski Reviewed-by: Alexey Dobriyan Signed-off-by: Alexey Gladkov --- Documentation/filesystems/proc.txt | 52 +++++++++++++++--------------- fs/proc/inode.c | 13 +++++++- fs/proc/root.c | 36 +++++++++++++++++++-- 3 files changed, 71 insertions(+), 30 deletions(-) diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index bd0e0ab85048..af47672cb2cb 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -2025,28 +2025,28 @@ The following mount options are supported: gid= Set the group authorized to learn processes information. subset= Show only the specified subset of procfs. -hidepid=0 means classic mode - everybody may access all /proc// directories -(default). - -hidepid=1 means users may not access any /proc// directories but their -own. Sensitive files like cmdline, sched*, status are now protected against -other users. This makes it impossible to learn whether any user runs -specific program (given the program doesn't reveal itself by its behaviour). -As an additional bonus, as /proc//cmdline is unaccessible for other users, -poorly written programs passing sensitive information via program arguments are -now protected against local eavesdroppers. - -hidepid=2 means hidepid=1 plus all /proc// will be fully invisible to other -users. It doesn't mean that it hides a fact whether a process with a specific -pid value exists (it can be learned by other means, e.g. by "kill -0 $PID"), -but it hides process' uid and gid, which may be learned by stat()'ing -/proc// otherwise. It greatly complicates an intruder's task of gathering -information about running processes, whether some daemon runs with elevated -privileges, whether other user runs some sensitive program, whether other users -run any program at all, etc. - -hidepid=4 means that procfs should only contain /proc// directories -that the caller can ptrace. +hidepid=off or hidepid=0 means classic mode - everybody may access all +/proc// directories (default). + +hidepid=noaccess or hidepid=1 means users may not access any /proc// +directories but their own. Sensitive files like cmdline, sched*, status are now +protected against other users. This makes it impossible to learn whether any +user runs specific program (given the program doesn't reveal itself by its +behaviour). As an additional bonus, as /proc//cmdline is unaccessible for +other users, poorly written programs passing sensitive information via program +arguments are now protected against local eavesdroppers. + +hidepid=invisible or hidepid=2 means hidepid=noaccess plus all /proc// will +be fully invisible to other users. It doesn't mean that it hides a fact whether +a process with a specific pid value exists (it can be learned by other means, +e.g. by "kill -0 $PID"), but it hides process' uid and gid, which may be learned +by stat()'ing /proc// otherwise. It greatly complicates an intruder's task +of gathering information about running processes, whether some daemon runs with +elevated privileges, whether other user runs some sensitive program, whether +other users run any program at all, etc. + +hidepid=ptraceable or hidepid=4 means that procfs should only contain +/proc// directories that the caller can ptrace. gid= defines a group authorized to learn processes information otherwise prohibited by hidepid=. If you use some daemon like identd which needs to learn @@ -2093,8 +2093,8 @@ creates a new procfs instance. Mount options affect own procfs instance. It means that it became possible to have several procfs instances displaying tasks with different filtering options in one pid namespace. -# mount -o hidepid=2 -t proc proc /proc -# mount -o hidepid=1 -t proc proc /tmp/proc +# mount -o hidepid=invisible -t proc proc /proc +# mount -o hidepid=noaccess -t proc proc /tmp/proc # grep ^proc /proc/mounts -proc /proc proc rw,relatime,hidepid=2 0 0 -proc /tmp/proc proc rw,relatime,hidepid=1 0 0 +proc /proc proc rw,relatime,hidepid=invisible 0 0 +proc /tmp/proc proc rw,relatime,hidepid=noaccess 0 0 diff --git a/fs/proc/inode.c b/fs/proc/inode.c index e6577ce6027b..f01fb4bed75c 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -165,6 +165,17 @@ void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock deactivate_super(old_sb); } +static inline const char *hidepid2str(int v) +{ + switch (v) { + case HIDEPID_OFF: return "off"; + case HIDEPID_NO_ACCESS: return "noaccess"; + case HIDEPID_INVISIBLE: return "invisible"; + case HIDEPID_NOT_PTRACEABLE: return "ptraceable"; + } + BUG(); +} + static int proc_show_options(struct seq_file *seq, struct dentry *root) { struct proc_fs_info *fs_info = proc_sb_info(root->d_sb); @@ -172,7 +183,7 @@ static int proc_show_options(struct seq_file *seq, struct dentry *root) if (!gid_eq(fs_info->pid_gid, GLOBAL_ROOT_GID)) seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid)); if (fs_info->hide_pid != HIDEPID_OFF) - seq_printf(seq, ",hidepid=%u", fs_info->hide_pid); + seq_printf(seq, ",hidepid=%s", hidepid2str(fs_info->hide_pid)); if (fs_info->pidonly != PROC_PIDONLY_OFF) seq_printf(seq, ",subset=pid"); diff --git a/fs/proc/root.c b/fs/proc/root.c index dbcd96f07c7a..ba782d6e6197 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -45,7 +45,7 @@ enum proc_param { static const struct fs_parameter_spec proc_fs_parameters[] = { fsparam_u32("gid", Opt_gid), - fsparam_u32("hidepid", Opt_hidepid), + fsparam_string("hidepid", Opt_hidepid), fsparam_string("subset", Opt_subset), {} }; @@ -58,6 +58,35 @@ static inline int valid_hidepid(unsigned int value) value == HIDEPID_NOT_PTRACEABLE); } +static int proc_parse_hidepid_param(struct fs_context *fc, struct fs_parameter *param) +{ + struct proc_fs_context *ctx = fc->fs_private; + struct fs_parameter_spec hidepid_u32_spec = fsparam_u32("hidepid", Opt_hidepid); + struct fs_parse_result result; + int base = (unsigned long)hidepid_u32_spec.data; + + if (param->type != fs_value_is_string) + return invalf(fc, "proc: unexpected type of hidepid value\n"); + + if (!kstrtouint(param->string, base, &result.uint_32)) { + ctx->hidepid = result.uint_32; + return 0; + } + + if (!strcmp(param->string, "off")) + ctx->hidepid = HIDEPID_OFF; + else if (!strcmp(param->string, "noaccess")) + ctx->hidepid = HIDEPID_NO_ACCESS; + else if (!strcmp(param->string, "invisible")) + ctx->hidepid = HIDEPID_INVISIBLE; + else if (!strcmp(param->string, "ptraceable")) + ctx->hidepid = HIDEPID_NOT_PTRACEABLE; + else + return invalf(fc, "proc: unknown value of hidepid - %s\n", param->string); + + return 0; +} + static int proc_parse_subset_param(struct fs_context *fc, char *value) { struct proc_fs_context *ctx = fc->fs_private; @@ -97,9 +126,10 @@ static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param) break; case Opt_hidepid: - if (!valid_hidepid(result.uint_32)) + if (proc_parse_hidepid_param(fc, param)) + return -EINVAL; + if (!valid_hidepid(ctx->hidepid)) return invalf(fc, "proc: unknown value of hidepid.\n"); - ctx->hidepid = result.uint_32; break; case Opt_subset: From patchwork Fri Mar 27 17:23:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Gladkov X-Patchwork-Id: 11462845 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 E7DAA1667 for ; Fri, 27 Mar 2020 17:32:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D05CF20838 for ; Fri, 27 Mar 2020 17:32:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727736AbgC0Rbo (ORCPT ); Fri, 27 Mar 2020 13:31:44 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:38834 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727593AbgC0Rbn (ORCPT ); Fri, 27 Mar 2020 13:31:43 -0400 Received: from comp-core-i7-2640m-0182e6.redhat.com (ip-89-102-33-211.net.upcbroadband.cz [89.102.33.211]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by raptor.unsafe.ru (Postfix) with ESMTPSA id 219CE20AB8; Fri, 27 Mar 2020 17:24:02 +0000 (UTC) From: Alexey Gladkov To: LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module Cc: Akinobu Mita , Alexander Viro , Alexey Dobriyan , Alexey Gladkov , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , "Eric W . Biederman" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Linus Torvalds , Oleg Nesterov Subject: [PATCH v10 9/9] proc: use named enums for better readability Date: Fri, 27 Mar 2020 18:23:31 +0100 Message-Id: <20200327172331.418878-10-gladkov.alexey@gmail.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200327172331.418878-1-gladkov.alexey@gmail.com> References: <20200327172331.418878-1-gladkov.alexey@gmail.com> MIME-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.1 (raptor.unsafe.ru [5.9.43.93]); Fri, 27 Mar 2020 17:24:02 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Suggested-by: Linus Torvalds Reviewed-by: Alexey Dobriyan Reviewed-by: Kees Cook Signed-off-by: Alexey Gladkov --- fs/proc/base.c | 2 +- fs/proc/inode.c | 2 +- fs/proc/root.c | 4 ++-- include/linux/proc_fs.h | 6 +++--- include/uapi/linux/proc_fs.h | 2 +- 5 files changed, 8 insertions(+), 8 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 1ebe9eba48ea..2f2f7b36c947 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -699,7 +699,7 @@ int proc_setattr(struct dentry *dentry, struct iattr *attr) */ static bool has_pid_permissions(struct proc_fs_info *fs_info, struct task_struct *task, - int hide_pid_min) + enum proc_hidepid hide_pid_min) { /* * If 'hidpid' mount option is set force a ptrace check, diff --git a/fs/proc/inode.c b/fs/proc/inode.c index f01fb4bed75c..77128bc36a05 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -165,7 +165,7 @@ void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock deactivate_super(old_sb); } -static inline const char *hidepid2str(int v) +static inline const char *hidepid2str(enum proc_hidepid v) { switch (v) { case HIDEPID_OFF: return "off"; diff --git a/fs/proc/root.c b/fs/proc/root.c index ba782d6e6197..00f75d8ef32f 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -32,9 +32,9 @@ struct proc_fs_context { struct proc_fs_info *fs_info; unsigned int mask; - int hidepid; + enum proc_hidepid hidepid; int gid; - int pidonly; + enum proc_pidonly pidonly; }; enum proc_param { diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index d259817ec913..b9f7ecd7f61f 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -29,7 +29,7 @@ struct proc_ops { }; /* definitions for proc mount option pidonly */ -enum { +enum proc_pidonly { PROC_PIDONLY_OFF = 0, PROC_PIDONLY_ON = 1, }; @@ -39,8 +39,8 @@ struct proc_fs_info { struct dentry *proc_self; /* For /proc/self */ struct dentry *proc_thread_self; /* For /proc/thread-self */ kgid_t pid_gid; - int hide_pid; - int pidonly; + enum proc_hidepid hide_pid; + enum proc_pidonly pidonly; }; static inline struct proc_fs_info *proc_sb_info(struct super_block *sb) diff --git a/include/uapi/linux/proc_fs.h b/include/uapi/linux/proc_fs.h index dc6d717aa6ec..f5fe0e8dcfe4 100644 --- a/include/uapi/linux/proc_fs.h +++ b/include/uapi/linux/proc_fs.h @@ -3,7 +3,7 @@ #define _UAPI_PROC_FS_H /* definitions for hide_pid field */ -enum { +enum proc_hidepid { HIDEPID_OFF = 0, HIDEPID_NO_ACCESS = 1, HIDEPID_INVISIBLE = 2,