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kernel/include/linux/proc_fs.h
Alexey Dobriyan c6c75deda8 proc: fix lookup in /proc/net subdirectories after setns(2) 
Commit 1fde6f21d9 ("proc: fix /proc/net/* after setns(2)") only forced
revalidation of regular files under /proc/net/

However, /proc/net/ is unusual in the sense of /proc/net/foo handlers
take netns pointer from parent directory which is old netns.

Steps to reproduce:

	(void)open("/proc/net/sctp/snmp", O_RDONLY);
	unshare(CLONE_NEWNET);

	int fd = open("/proc/net/sctp/snmp", O_RDONLY);
	read(fd, &c, 1);

Read will read wrong data from original netns.

Patch forces lookup on every directory under /proc/net .

Link: https://lkml.kernel.org/r/20201205160916.GA109739@localhost.localdomain
Fixes: 1da4d377f9 ("proc: revalidate misc dentries")
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reported-by: "Rantala, Tommi T. (Nokia - FI/Espoo)" <tommi.t.rantala@nokia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 22:46:15 -08:00

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* The proc filesystem constants/structures
*/
#ifndef _LINUX_PROC_FS_H
#define _LINUX_PROC_FS_H
#include <linux/compiler.h>
#include <linux/types.h>
#include <linux/fs.h>
struct proc_dir_entry;
struct seq_file;
struct seq_operations;
enum {
/*
* All /proc entries using this ->proc_ops instance are never removed.
*
* If in doubt, ignore this flag.
*/
#ifdef MODULE
PROC_ENTRY_PERMANENT = 0U,
#else
PROC_ENTRY_PERMANENT = 1U << 0,
#endif
};
struct proc_ops {
unsigned int proc_flags;
int (*proc_open)(struct inode *, struct file *);
ssize_t (*proc_read)(struct file *, char __user *, size_t, loff_t *);
ssize_t (*proc_read_iter)(struct kiocb *, struct iov_iter *);
ssize_t (*proc_write)(struct file *, const char __user *, size_t, loff_t *);
loff_t (*proc_lseek)(struct file *, loff_t, int);
int (*proc_release)(struct inode *, struct file *);
__poll_t (*proc_poll)(struct file *, struct poll_table_struct *);
long (*proc_ioctl)(struct file *, unsigned int, unsigned long);
#ifdef CONFIG_COMPAT
long (*proc_compat_ioctl)(struct file *, unsigned int, unsigned long);
#endif
int (*proc_mmap)(struct file *, struct vm_area_struct *);
unsigned long (*proc_get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
} __randomize_layout;
/* definitions for hide_pid field */
enum proc_hidepid {
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 {
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;
enum proc_hidepid hide_pid;
enum proc_pidonly pidonly;
};
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);
extern void proc_root_init(void);
extern void proc_flush_pid(struct pid *);
extern struct proc_dir_entry *proc_symlink(const char *,
struct proc_dir_entry *, const char *);
struct proc_dir_entry *_proc_mkdir(const char *, umode_t, struct proc_dir_entry *, void *, bool);
extern struct proc_dir_entry *proc_mkdir(const char *, struct proc_dir_entry *);
extern struct proc_dir_entry *proc_mkdir_data(const char *, umode_t,
struct proc_dir_entry *, void *);
extern struct proc_dir_entry *proc_mkdir_mode(const char *, umode_t,
struct proc_dir_entry *);
struct proc_dir_entry *proc_create_mount_point(const char *name);
struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
struct proc_dir_entry *parent, const struct seq_operations *ops,
unsigned int state_size, void *data);
#define proc_create_seq_data(name, mode, parent, ops, data) \
proc_create_seq_private(name, mode, parent, ops, 0, data)
#define proc_create_seq(name, mode, parent, ops) \
proc_create_seq_private(name, mode, parent, ops, 0, NULL)
struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode,
struct proc_dir_entry *parent,
int (*show)(struct seq_file *, void *), void *data);
#define proc_create_single(name, mode, parent, show) \
proc_create_single_data(name, mode, parent, show, NULL)
extern struct proc_dir_entry *proc_create_data(const char *, umode_t,
struct proc_dir_entry *,
const struct proc_ops *,
void *);
struct proc_dir_entry *proc_create(const char *name, umode_t mode, struct proc_dir_entry *parent, const struct proc_ops *proc_ops);
extern void proc_set_size(struct proc_dir_entry *, loff_t);
extern void proc_set_user(struct proc_dir_entry *, kuid_t, kgid_t);
extern void *PDE_DATA(const struct inode *);
extern void *proc_get_parent_data(const struct inode *);
extern void proc_remove(struct proc_dir_entry *);
extern void remove_proc_entry(const char *, struct proc_dir_entry *);
extern int remove_proc_subtree(const char *, struct proc_dir_entry *);
struct proc_dir_entry *proc_create_net_data(const char *name, umode_t mode,
struct proc_dir_entry *parent, const struct seq_operations *ops,
unsigned int state_size, void *data);
#define proc_create_net(name, mode, parent, ops, state_size) \
proc_create_net_data(name, mode, parent, ops, state_size, NULL)
struct proc_dir_entry *proc_create_net_single(const char *name, umode_t mode,
struct proc_dir_entry *parent,
int (*show)(struct seq_file *, void *), void *data);
struct proc_dir_entry *proc_create_net_data_write(const char *name, umode_t mode,
struct proc_dir_entry *parent,
const struct seq_operations *ops,
proc_write_t write,
unsigned int state_size, void *data);
struct proc_dir_entry *proc_create_net_single_write(const char *name, umode_t mode,
struct proc_dir_entry *parent,
int (*show)(struct seq_file *, void *),
proc_write_t write,
void *data);
extern struct pid *tgid_pidfd_to_pid(const struct file *file);
struct bpf_iter_aux_info;
extern int bpf_iter_init_seq_net(void *priv_data, struct bpf_iter_aux_info *aux);
extern void bpf_iter_fini_seq_net(void *priv_data);
#ifdef CONFIG_PROC_PID_ARCH_STATUS
/*
* The architecture which selects CONFIG_PROC_PID_ARCH_STATUS must
* provide proc_pid_arch_status() definition.
*/
int proc_pid_arch_status(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task);
#endif /* CONFIG_PROC_PID_ARCH_STATUS */
#else /* CONFIG_PROC_FS */
static inline void proc_root_init(void)
{
}
static inline void proc_flush_pid(struct pid *pid)
{
}
static inline struct proc_dir_entry *proc_symlink(const char *name,
struct proc_dir_entry *parent,const char *dest) { return NULL;}
static inline struct proc_dir_entry *proc_mkdir(const char *name,
struct proc_dir_entry *parent) {return NULL;}
static inline struct proc_dir_entry *proc_create_mount_point(const char *name) { return NULL; }
static inline struct proc_dir_entry *_proc_mkdir(const char *name, umode_t mode,
struct proc_dir_entry *parent, void *data, bool force_lookup)
{
return NULL;
}
static inline struct proc_dir_entry *proc_mkdir_data(const char *name,
umode_t mode, struct proc_dir_entry *parent, void *data) { return NULL; }
static inline struct proc_dir_entry *proc_mkdir_mode(const char *name,
umode_t mode, struct proc_dir_entry *parent) { return NULL; }
#define proc_create_seq_private(name, mode, parent, ops, size, data) ({NULL;})
#define proc_create_seq_data(name, mode, parent, ops, data) ({NULL;})
#define proc_create_seq(name, mode, parent, ops) ({NULL;})
#define proc_create_single(name, mode, parent, show) ({NULL;})
#define proc_create_single_data(name, mode, parent, show, data) ({NULL;})
#define proc_create(name, mode, parent, proc_ops) ({NULL;})
#define proc_create_data(name, mode, parent, proc_ops, data) ({NULL;})
static inline void proc_set_size(struct proc_dir_entry *de, loff_t size) {}
static inline void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid) {}
static inline void *PDE_DATA(const struct inode *inode) {BUG(); return NULL;}
static inline void *proc_get_parent_data(const struct inode *inode) { BUG(); return NULL; }
static inline void proc_remove(struct proc_dir_entry *de) {}
#define remove_proc_entry(name, parent) do {} while (0)
static inline int remove_proc_subtree(const char *name, struct proc_dir_entry *parent) { return 0; }
#define proc_create_net_data(name, mode, parent, ops, state_size, data) ({NULL;})
#define proc_create_net(name, mode, parent, state_size, ops) ({NULL;})
#define proc_create_net_single(name, mode, parent, show, data) ({NULL;})
static inline struct pid *tgid_pidfd_to_pid(const struct file *file)
{
return ERR_PTR(-EBADF);
}
#endif /* CONFIG_PROC_FS */
struct net;
static inline struct proc_dir_entry *proc_net_mkdir(
struct net *net, const char *name, struct proc_dir_entry *parent)
{
return _proc_mkdir(name, 0, parent, net, true);
}
struct ns_common;
int open_related_ns(struct ns_common *ns,
struct ns_common *(*get_ns)(struct ns_common *ns));
/* get the associated pid namespace for a file in procfs */
static inline struct pid_namespace *proc_pid_ns(struct super_block *sb)
{
return proc_sb_info(sb)->pid_ns;
}
bool proc_ns_file(const struct file *file);
#endif /* _LINUX_PROC_FS_H */
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