Release 4.17 fs/proc/namespaces.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/proc_fs.h>
#include <linux/nsproxy.h>
#include <linux/ptrace.h>
#include <linux/namei.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <net/net_namespace.h>
#include <linux/ipc_namespace.h>
#include <linux/pid_namespace.h>
#include <linux/user_namespace.h>
#include "internal.h"



static const struct proc_ns_operations *ns_entries[] = {
#ifdef CONFIG_NET_NS
	&netns_operations,
#endif
#ifdef CONFIG_UTS_NS
	&utsns_operations,
#endif
#ifdef CONFIG_IPC_NS
	&ipcns_operations,
#endif
#ifdef CONFIG_PID_NS
	&pidns_operations,
	&pidns_for_children_operations,
#endif
#ifdef CONFIG_USER_NS
	&userns_operations,
#endif
	&mntns_operations,
#ifdef CONFIG_CGROUPS
	&cgroupns_operations,
#endif
};



static const char *proc_ns_get_link(struct dentry *dentry,
				    struct inode *inode,
				    struct delayed_call *done)
{
	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
	struct task_struct *task;
	struct path ns_path;
	void *error = ERR_PTR(-EACCES);

	if (!dentry)
		return ERR_PTR(-ECHILD);

	task = get_proc_task(inode);
	if (!task)
		return error;

	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
		error = ns_get_path(&ns_path, task, ns_ops);
		if (!error)
			nd_jump_link(&ns_path);
	}
	put_task_struct(task);
	return error;
}

Contributors
Person
Tokens
Prop
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CommitProp
Eric W. Biedermann
83
66.94%
2
28.57%
Al Viro
40
32.26%
4
57.14%
Jann Horn
1
0.81%
1
14.29%
Total
124
100.00%
7
100.00%



static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen)
{
	struct inode *inode = d_inode(dentry);
	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
	struct task_struct *task;
	char name[50];
	int res = -EACCES;

	task = get_proc_task(inode);
	if (!task)
		return res;

	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
		res = ns_get_name(name, sizeof(name), task, ns_ops);
		if (res >= 0)
			res = readlink_copy(buffer, buflen, name);
	}
	put_task_struct(task);
	return res;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Eric W. Biedermann
99
78.57%
1
20.00%
Al Viro
23
18.25%
2
40.00%
David Howells
3
2.38%
1
20.00%
Jann Horn
1
0.79%
1
20.00%
Total
126
100.00%
5
100.00%


static const struct inode_operations proc_ns_link_inode_operations = {
	.readlink	= proc_ns_readlink,
	.get_link	= proc_ns_get_link,
	.setattr	= proc_setattr,
};



static int proc_ns_instantiate(struct inode *dir,
	struct dentry *dentry, struct task_struct *task, const void *ptr)
{
	const struct proc_ns_operations *ns_ops = ptr;
	struct inode *inode;
	struct proc_inode *ei;

	inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK | S_IRWXUGO);
	if (!inode)
		goto out;

	ei = PROC_I(inode);
	inode->i_op = &proc_ns_link_inode_operations;
	ei->ns_ops = ns_ops;

	d_set_d_op(dentry, &pid_dentry_operations);
	d_add(dentry, inode);
	/* Close the race of the process dying before we return the dentry */
	if (pid_revalidate(dentry, 0))
		return 0;
out:
	return -ENOENT;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Eric W. Biedermann
106
87.60%
2
33.33%
Al Viro
7
5.79%
2
33.33%
Pravin B Shelar
4
3.31%
1
16.67%
Andreas Gruenbacher
4
3.31%
1
16.67%
Total
121
100.00%
6
100.00%



static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx)
{
	struct task_struct *task = get_proc_task(file_inode(file));
	const struct proc_ns_operations **entry, **last;

	if (!task)
		return -ENOENT;

	if (!dir_emit_dots(file, ctx))
		goto out;
	if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries))
		goto out;
	entry = ns_entries + (ctx->pos - 2);
	last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
	while (entry <= last) {
		const struct proc_ns_operations *ops = *entry;
		if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name),
				     proc_ns_instantiate, task, ops))
			break;
		ctx->pos++;
		entry++;
	}
out:
	put_task_struct(task);
	return 0;
}

Contributors
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Tokens
Prop
Commits
CommitProp
Eric W. Biedermann
109
65.66%
1
50.00%
Al Viro
57
34.34%
1
50.00%
Total
166
100.00%
2
100.00%


const struct file_operations proc_ns_dir_operations = {
	.read		= generic_read_dir,
	.iterate_shared	= proc_ns_dir_readdir,
	.llseek		= generic_file_llseek,
};



static struct dentry *proc_ns_dir_lookup(struct inode *dir,
				struct dentry *dentry, unsigned int flags)
{
	int error;
	struct task_struct *task = get_proc_task(dir);
	const struct proc_ns_operations **entry, **last;
	unsigned int len = dentry->d_name.len;

	error = -ENOENT;

	if (!task)
		goto out_no_task;

	last = &ns_entries[ARRAY_SIZE(ns_entries)];
	for (entry = ns_entries; entry < last; entry++) {
		if (strlen((*entry)->name) != len)
			continue;
		if (!memcmp(dentry->d_name.name, (*entry)->name, len))
			break;
	}
	if (entry == last)
		goto out;

	error = proc_ns_instantiate(dir, dentry, task, *entry);
out:
	put_task_struct(task);
out_no_task:
	return ERR_PTR(error);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Eric W. Biedermann
161
94.71%
1
25.00%
Al Viro
7
4.12%
2
50.00%
Andrew Morton
2
1.18%
1
25.00%
Total
170
100.00%
4
100.00%


const struct inode_operations proc_ns_dir_inode_operations = {
	.lookup		= proc_ns_dir_lookup,
	.getattr	= pid_getattr,
	.setattr	= proc_setattr,
};
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Eric W. Biedermann
682
78.12%
7
28.00%
Al Viro
162
18.56%
10
40.00%
Aditya Kali
10
1.15%
1
4.00%
Pravin B Shelar
4
0.46%
1
4.00%
Andreas Gruenbacher
4
0.46%
1
4.00%
Kirill Tkhai
3
0.34%
1
4.00%
David Howells
3
0.34%
1
4.00%
Andrew Morton
2
0.23%
1
4.00%
Jann Horn
2
0.23%
1
4.00%
Greg Kroah-Hartman
1
0.11%
1
4.00%
Total
873
100.00%
25
100.00%
Directory: fs/proc

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