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Message-Id: <20200210150519.538333-5-gladkov.alexey@gmail.com>
Date: Mon, 10 Feb 2020 16:05:12 +0100
From: Alexey Gladkov <gladkov.alexey@...il.com>
To: LKML <linux-kernel@...r.kernel.org>,
Kernel Hardening <kernel-hardening@...ts.openwall.com>,
Linux API <linux-api@...r.kernel.org>,
Linux FS Devel <linux-fsdevel@...r.kernel.org>,
Linux Security Module <linux-security-module@...r.kernel.org>
Cc: Akinobu Mita <akinobu.mita@...il.com>,
Alexander Viro <viro@...iv.linux.org.uk>,
Alexey Dobriyan <adobriyan@...il.com>,
Alexey Gladkov <gladkov.alexey@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Andy Lutomirski <luto@...nel.org>,
Daniel Micay <danielmicay@...il.com>,
Djalal Harouni <tixxdz@...il.com>,
"Dmitry V . Levin" <ldv@...linux.org>,
"Eric W . Biederman" <ebiederm@...ssion.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Ingo Molnar <mingo@...nel.org>,
"J . Bruce Fields" <bfields@...ldses.org>,
Jeff Layton <jlayton@...chiereds.net>,
Jonathan Corbet <corbet@....net>,
Kees Cook <keescook@...omium.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Oleg Nesterov <oleg@...hat.com>,
Solar Designer <solar@...nwall.com>
Subject: [PATCH v8 04/11] proc: move hide_pid, pid_gid from pid_namespace to proc_fs_info
This is a preparation patch that moves hide_pid and pid_gid parameters
to be stored inside procfs fs_info struct instead of making them per pid
namespace. Since we want to support multiple procfs instances we need to
make sure that all proc-specific parameters are also per-superblock.
Signed-off-by: Alexey Gladkov <gladkov.alexey@...il.com>
---
fs/proc/base.c | 18 +++++++++---------
fs/proc/inode.c | 9 ++++-----
fs/proc/root.c | 10 ++++++++--
include/linux/pid_namespace.h | 8 --------
include/linux/proc_fs.h | 9 +++++++++
5 files changed, 30 insertions(+), 24 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1eb366ad8b06..caca1929fee1 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -695,13 +695,13 @@ 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);
}
@@ -709,18 +709,18 @@ 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
@@ -1784,7 +1784,7 @@ 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);
@@ -1794,7 +1794,7 @@ 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,
@@ -3344,7 +3344,7 @@ 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 b631608dfbcc..b90c233e5968 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -105,12 +105,11 @@ void __init proc_init_kmemcache(void)
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 637e26cc795e..1ca47d446aa4 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -89,10 +89,16 @@ static void proc_apply_options(struct super_block *s,
{
struct proc_fs_context *ctx = fc->fs_private;
+ if (pid_ns->proc_mnt) {
+ struct proc_fs_info *fs_info = proc_sb_info(pid_ns->proc_mnt->mnt_sb);
+ ctx->fs_info->pid_gid = fs_info->pid_gid;
+ ctx->fs_info->hide_pid = fs_info->hide_pid;
+ }
+
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 f91a8bf6e09e..66f47f1afe0d 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -15,12 +15,6 @@
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;
@@ -39,8 +33,6 @@ struct pid_namespace {
struct user_namespace *user_ns;
struct ucounts *ucounts;
struct work_struct proc_work;
- 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 59162988998e..5f0b1b7e4271 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -12,10 +12,19 @@ struct proc_dir_entry;
struct seq_file;
struct seq_operations;
+/* 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)
--
2.24.1
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