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105ff5339f
The new MFD_NOEXEC_SEAL and MFD_EXEC flags allows application to set
executable bit at creation time (memfd_create).
When MFD_NOEXEC_SEAL is set, memfd is created without executable bit
(mode:0666), and sealed with F_SEAL_EXEC, so it can't be chmod to be
executable (mode: 0777) after creation.
when MFD_EXEC flag is set, memfd is created with executable bit
(mode:0777), this is the same as the old behavior of memfd_create.
The new pid namespaced sysctl vm.memfd_noexec has 3 values:
0: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL acts like
MFD_EXEC was set.
1: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL acts like
MFD_NOEXEC_SEAL was set.
2: memfd_create() without MFD_NOEXEC_SEAL will be rejected.
The sysctl allows finer control of memfd_create for old-software that
doesn't set the executable bit, for example, a container with
vm.memfd_noexec=1 means the old-software will create non-executable memfd
by default. Also, the value of memfd_noexec is passed to child namespace
at creation time. For example, if the init namespace has
vm.memfd_noexec=2, all its children namespaces will be created with 2.
[akpm@linux-foundation.org: add stub functions to fix build]
[akpm@linux-foundation.org: remove unneeded register_pid_ns_ctl_table_vm() stub, per Jeff]
[akpm@linux-foundation.org: s/pr_warn_ratelimited/pr_warn_once/, per review]
[akpm@linux-foundation.org: fix CONFIG_SYSCTL=n warning]
Link: https://lkml.kernel.org/r/20221215001205.51969-4-jeffxu@google.com
Signed-off-by: Jeff Xu <jeffxu@google.com>
Co-developed-by: Daniel Verkamp <dverkamp@chromium.org>
Signed-off-by: Daniel Verkamp <dverkamp@chromium.org>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
113 lines
2.8 KiB
C
113 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_PID_NS_H
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#define _LINUX_PID_NS_H
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#include <linux/sched.h>
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#include <linux/bug.h>
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#include <linux/mm.h>
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#include <linux/workqueue.h>
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#include <linux/threads.h>
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#include <linux/nsproxy.h>
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#include <linux/ns_common.h>
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#include <linux/idr.h>
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/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
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#define MAX_PID_NS_LEVEL 32
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struct fs_pin;
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#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
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/*
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* sysctl for vm.memfd_noexec
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* 0: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL
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* acts like MFD_EXEC was set.
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* 1: memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL
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* acts like MFD_NOEXEC_SEAL was set.
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* 2: memfd_create() without MFD_NOEXEC_SEAL will be
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* rejected.
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*/
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#define MEMFD_NOEXEC_SCOPE_EXEC 0
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#define MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL 1
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#define MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED 2
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#endif
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struct pid_namespace {
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struct idr idr;
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struct rcu_head rcu;
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unsigned int pid_allocated;
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struct task_struct *child_reaper;
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struct kmem_cache *pid_cachep;
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unsigned int level;
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struct pid_namespace *parent;
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#ifdef CONFIG_BSD_PROCESS_ACCT
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struct fs_pin *bacct;
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#endif
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struct user_namespace *user_ns;
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struct ucounts *ucounts;
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int reboot; /* group exit code if this pidns was rebooted */
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struct ns_common ns;
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#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
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/* sysctl for vm.memfd_noexec */
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int memfd_noexec_scope;
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#endif
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} __randomize_layout;
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extern struct pid_namespace init_pid_ns;
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#define PIDNS_ADDING (1U << 31)
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#ifdef CONFIG_PID_NS
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static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
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{
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if (ns != &init_pid_ns)
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refcount_inc(&ns->ns.count);
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return ns;
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}
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extern struct pid_namespace *copy_pid_ns(unsigned long flags,
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struct user_namespace *user_ns, struct pid_namespace *ns);
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extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
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extern int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd);
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extern void put_pid_ns(struct pid_namespace *ns);
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#else /* !CONFIG_PID_NS */
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#include <linux/err.h>
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static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
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{
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return ns;
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}
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static inline struct pid_namespace *copy_pid_ns(unsigned long flags,
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struct user_namespace *user_ns, struct pid_namespace *ns)
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{
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if (flags & CLONE_NEWPID)
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ns = ERR_PTR(-EINVAL);
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return ns;
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}
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static inline void put_pid_ns(struct pid_namespace *ns)
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{
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}
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static inline void zap_pid_ns_processes(struct pid_namespace *ns)
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{
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BUG();
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}
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static inline int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
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{
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return 0;
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}
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#endif /* CONFIG_PID_NS */
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extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk);
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void pidhash_init(void);
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void pid_idr_init(void);
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static inline bool task_is_in_init_pid_ns(struct task_struct *tsk)
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{
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return task_active_pid_ns(tsk) == &init_pid_ns;
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}
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#endif /* _LINUX_PID_NS_H */
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