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linux-next/fs/afs/proc.c
David Howells 6b3944e42e afs: Fix cell proc list
Access to the list of cells by /proc/net/afs/cells has a couple of
problems:

 (1) It should be checking against SEQ_START_TOKEN for the keying the
     header line.

 (2) It's only holding the RCU read lock, so it can't just walk over the
     list without following the proper RCU methods.

Fix these by using an hlist instead of an ordinary list and using the
appropriate accessor functions to follow it with RCU.

Since the code that adds a cell to the list must also necessarily change,
sort the list on insertion whilst we're at it.

Fixes: 989782dcdc ("afs: Overhaul cell database management")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-12 13:18:57 +02:00

646 lines
14 KiB
C

/* /proc interface for AFS
*
* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include "internal.h"
static inline struct afs_net *afs_seq2net(struct seq_file *m)
{
return afs_net(seq_file_net(m));
}
static inline struct afs_net *afs_seq2net_single(struct seq_file *m)
{
return afs_net(seq_file_single_net(m));
}
/*
* Display the list of cells known to the namespace.
*/
static int afs_proc_cells_show(struct seq_file *m, void *v)
{
struct afs_cell *cell = list_entry(v, struct afs_cell, proc_link);
if (v == SEQ_START_TOKEN) {
/* display header on line 1 */
seq_puts(m, "USE NAME\n");
return 0;
}
/* display one cell per line on subsequent lines */
seq_printf(m, "%3u %s\n", atomic_read(&cell->usage), cell->name);
return 0;
}
static void *afs_proc_cells_start(struct seq_file *m, loff_t *_pos)
__acquires(rcu)
{
rcu_read_lock();
return seq_hlist_start_head_rcu(&afs_seq2net(m)->proc_cells, *_pos);
}
static void *afs_proc_cells_next(struct seq_file *m, void *v, loff_t *pos)
{
return seq_hlist_next_rcu(v, &afs_seq2net(m)->proc_cells, pos);
}
static void afs_proc_cells_stop(struct seq_file *m, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
static const struct seq_operations afs_proc_cells_ops = {
.start = afs_proc_cells_start,
.next = afs_proc_cells_next,
.stop = afs_proc_cells_stop,
.show = afs_proc_cells_show,
};
/*
* handle writes to /proc/fs/afs/cells
* - to add cells: echo "add <cellname> <IP>[:<IP>][:<IP>]"
*/
static int afs_proc_cells_write(struct file *file, char *buf, size_t size)
{
struct seq_file *m = file->private_data;
struct afs_net *net = afs_seq2net(m);
char *name, *args;
int ret;
/* trim to first NL */
name = memchr(buf, '\n', size);
if (name)
*name = 0;
/* split into command, name and argslist */
name = strchr(buf, ' ');
if (!name)
goto inval;
do {
*name++ = 0;
} while(*name == ' ');
if (!*name)
goto inval;
args = strchr(name, ' ');
if (args) {
do {
*args++ = 0;
} while(*args == ' ');
if (!*args)
goto inval;
}
/* determine command to perform */
_debug("cmd=%s name=%s args=%s", buf, name, args);
if (strcmp(buf, "add") == 0) {
struct afs_cell *cell;
cell = afs_lookup_cell(net, name, strlen(name), args, true);
if (IS_ERR(cell)) {
ret = PTR_ERR(cell);
goto done;
}
if (test_and_set_bit(AFS_CELL_FL_NO_GC, &cell->flags))
afs_put_cell(net, cell);
} else {
goto inval;
}
ret = 0;
done:
_leave(" = %d", ret);
return ret;
inval:
ret = -EINVAL;
printk("kAFS: Invalid Command on /proc/fs/afs/cells file\n");
goto done;
}
/*
* Display the name of the current workstation cell.
*/
static int afs_proc_rootcell_show(struct seq_file *m, void *v)
{
struct afs_cell *cell;
struct afs_net *net;
net = afs_seq2net_single(m);
if (rcu_access_pointer(net->ws_cell)) {
rcu_read_lock();
cell = rcu_dereference(net->ws_cell);
if (cell)
seq_printf(m, "%s\n", cell->name);
rcu_read_unlock();
}
return 0;
}
/*
* Set the current workstation cell and optionally supply its list of volume
* location servers.
*
* echo "cell.name:192.168.231.14" >/proc/fs/afs/rootcell
*/
static int afs_proc_rootcell_write(struct file *file, char *buf, size_t size)
{
struct seq_file *m = file->private_data;
struct afs_net *net = afs_seq2net_single(m);
char *s;
int ret;
ret = -EINVAL;
if (buf[0] == '.')
goto out;
if (memchr(buf, '/', size))
goto out;
/* trim to first NL */
s = memchr(buf, '\n', size);
if (s)
*s = 0;
/* determine command to perform */
_debug("rootcell=%s", buf);
ret = afs_cell_init(net, buf);
out:
_leave(" = %d", ret);
return ret;
}
static const char afs_vol_types[3][3] = {
[AFSVL_RWVOL] = "RW",
[AFSVL_ROVOL] = "RO",
[AFSVL_BACKVOL] = "BK",
};
/*
* Display the list of volumes known to a cell.
*/
static int afs_proc_cell_volumes_show(struct seq_file *m, void *v)
{
struct afs_cell *cell = PDE_DATA(file_inode(m->file));
struct afs_volume *vol = list_entry(v, struct afs_volume, proc_link);
/* Display header on line 1 */
if (v == &cell->proc_volumes) {
seq_puts(m, "USE VID TY\n");
return 0;
}
seq_printf(m, "%3d %08x %s\n",
atomic_read(&vol->usage), vol->vid,
afs_vol_types[vol->type]);
return 0;
}
static void *afs_proc_cell_volumes_start(struct seq_file *m, loff_t *_pos)
__acquires(cell->proc_lock)
{
struct afs_cell *cell = PDE_DATA(file_inode(m->file));
read_lock(&cell->proc_lock);
return seq_list_start_head(&cell->proc_volumes, *_pos);
}
static void *afs_proc_cell_volumes_next(struct seq_file *m, void *v,
loff_t *_pos)
{
struct afs_cell *cell = PDE_DATA(file_inode(m->file));
return seq_list_next(v, &cell->proc_volumes, _pos);
}
static void afs_proc_cell_volumes_stop(struct seq_file *m, void *v)
__releases(cell->proc_lock)
{
struct afs_cell *cell = PDE_DATA(file_inode(m->file));
read_unlock(&cell->proc_lock);
}
static const struct seq_operations afs_proc_cell_volumes_ops = {
.start = afs_proc_cell_volumes_start,
.next = afs_proc_cell_volumes_next,
.stop = afs_proc_cell_volumes_stop,
.show = afs_proc_cell_volumes_show,
};
/*
* Display the list of Volume Location servers we're using for a cell.
*/
static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v)
{
struct sockaddr_rxrpc *addr = v;
/* display header on line 1 */
if (v == (void *)1) {
seq_puts(m, "ADDRESS\n");
return 0;
}
/* display one cell per line on subsequent lines */
seq_printf(m, "%pISp\n", &addr->transport);
return 0;
}
static void *afs_proc_cell_vlservers_start(struct seq_file *m, loff_t *_pos)
__acquires(rcu)
{
struct afs_addr_list *alist;
struct afs_cell *cell = PDE_DATA(file_inode(m->file));
loff_t pos = *_pos;
rcu_read_lock();
alist = rcu_dereference(cell->vl_addrs);
/* allow for the header line */
if (!pos)
return (void *) 1;
pos--;
if (!alist || pos >= alist->nr_addrs)
return NULL;
return alist->addrs + pos;
}
static void *afs_proc_cell_vlservers_next(struct seq_file *m, void *v,
loff_t *_pos)
{
struct afs_addr_list *alist;
struct afs_cell *cell = PDE_DATA(file_inode(m->file));
loff_t pos;
alist = rcu_dereference(cell->vl_addrs);
pos = *_pos;
(*_pos)++;
if (!alist || pos >= alist->nr_addrs)
return NULL;
return alist->addrs + pos;
}
static void afs_proc_cell_vlservers_stop(struct seq_file *m, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
static const struct seq_operations afs_proc_cell_vlservers_ops = {
.start = afs_proc_cell_vlservers_start,
.next = afs_proc_cell_vlservers_next,
.stop = afs_proc_cell_vlservers_stop,
.show = afs_proc_cell_vlservers_show,
};
/*
* Display the list of fileservers we're using within a namespace.
*/
static int afs_proc_servers_show(struct seq_file *m, void *v)
{
struct afs_server *server;
struct afs_addr_list *alist;
int i;
if (v == SEQ_START_TOKEN) {
seq_puts(m, "UUID USE ADDR\n");
return 0;
}
server = list_entry(v, struct afs_server, proc_link);
alist = rcu_dereference(server->addresses);
seq_printf(m, "%pU %3d %pISpc%s\n",
&server->uuid,
atomic_read(&server->usage),
&alist->addrs[0].transport,
alist->index == 0 ? "*" : "");
for (i = 1; i < alist->nr_addrs; i++)
seq_printf(m, " %pISpc%s\n",
&alist->addrs[i].transport,
alist->index == i ? "*" : "");
return 0;
}
static void *afs_proc_servers_start(struct seq_file *m, loff_t *_pos)
__acquires(rcu)
{
rcu_read_lock();
return seq_hlist_start_head_rcu(&afs_seq2net(m)->fs_proc, *_pos);
}
static void *afs_proc_servers_next(struct seq_file *m, void *v, loff_t *_pos)
{
return seq_hlist_next_rcu(v, &afs_seq2net(m)->fs_proc, _pos);
}
static void afs_proc_servers_stop(struct seq_file *m, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
static const struct seq_operations afs_proc_servers_ops = {
.start = afs_proc_servers_start,
.next = afs_proc_servers_next,
.stop = afs_proc_servers_stop,
.show = afs_proc_servers_show,
};
/*
* Display the list of strings that may be substituted for the @sys pathname
* macro.
*/
static int afs_proc_sysname_show(struct seq_file *m, void *v)
{
struct afs_net *net = afs_seq2net(m);
struct afs_sysnames *sysnames = net->sysnames;
unsigned int i = (unsigned long)v - 1;
if (i < sysnames->nr)
seq_printf(m, "%s\n", sysnames->subs[i]);
return 0;
}
static void *afs_proc_sysname_start(struct seq_file *m, loff_t *pos)
__acquires(&net->sysnames_lock)
{
struct afs_net *net = afs_seq2net(m);
struct afs_sysnames *names;
read_lock(&net->sysnames_lock);
names = net->sysnames;
if (*pos >= names->nr)
return NULL;
return (void *)(unsigned long)(*pos + 1);
}
static void *afs_proc_sysname_next(struct seq_file *m, void *v, loff_t *pos)
{
struct afs_net *net = afs_seq2net(m);
struct afs_sysnames *names = net->sysnames;
*pos += 1;
if (*pos >= names->nr)
return NULL;
return (void *)(unsigned long)(*pos + 1);
}
static void afs_proc_sysname_stop(struct seq_file *m, void *v)
__releases(&net->sysnames_lock)
{
struct afs_net *net = afs_seq2net(m);
read_unlock(&net->sysnames_lock);
}
static const struct seq_operations afs_proc_sysname_ops = {
.start = afs_proc_sysname_start,
.next = afs_proc_sysname_next,
.stop = afs_proc_sysname_stop,
.show = afs_proc_sysname_show,
};
/*
* Allow the @sys substitution to be configured.
*/
static int afs_proc_sysname_write(struct file *file, char *buf, size_t size)
{
struct afs_sysnames *sysnames, *kill;
struct seq_file *m = file->private_data;
struct afs_net *net = afs_seq2net(m);
char *s, *p, *sub;
int ret, len;
sysnames = kzalloc(sizeof(*sysnames), GFP_KERNEL);
if (!sysnames)
return -ENOMEM;
refcount_set(&sysnames->usage, 1);
kill = sysnames;
p = buf;
while ((s = strsep(&p, " \t\n"))) {
len = strlen(s);
if (len == 0)
continue;
ret = -ENAMETOOLONG;
if (len >= AFSNAMEMAX)
goto error;
if (len >= 4 &&
s[len - 4] == '@' &&
s[len - 3] == 's' &&
s[len - 2] == 'y' &&
s[len - 1] == 's')
/* Protect against recursion */
goto invalid;
if (s[0] == '.' &&
(len < 2 || (len == 2 && s[1] == '.')))
goto invalid;
if (memchr(s, '/', len))
goto invalid;
ret = -EFBIG;
if (sysnames->nr >= AFS_NR_SYSNAME)
goto out;
if (strcmp(s, afs_init_sysname) == 0) {
sub = (char *)afs_init_sysname;
} else {
ret = -ENOMEM;
sub = kmemdup(s, len + 1, GFP_KERNEL);
if (!sub)
goto out;
}
sysnames->subs[sysnames->nr] = sub;
sysnames->nr++;
}
if (sysnames->nr == 0) {
sysnames->subs[0] = sysnames->blank;
sysnames->nr++;
}
write_lock(&net->sysnames_lock);
kill = net->sysnames;
net->sysnames = sysnames;
write_unlock(&net->sysnames_lock);
ret = 0;
out:
afs_put_sysnames(kill);
return ret;
invalid:
ret = -EINVAL;
error:
goto out;
}
void afs_put_sysnames(struct afs_sysnames *sysnames)
{
int i;
if (sysnames && refcount_dec_and_test(&sysnames->usage)) {
for (i = 0; i < sysnames->nr; i++)
if (sysnames->subs[i] != afs_init_sysname &&
sysnames->subs[i] != sysnames->blank)
kfree(sysnames->subs[i]);
}
}
/*
* Display general per-net namespace statistics
*/
static int afs_proc_stats_show(struct seq_file *m, void *v)
{
struct afs_net *net = afs_seq2net_single(m);
seq_puts(m, "kAFS statistics\n");
seq_printf(m, "dir-mgmt: look=%u reval=%u inval=%u relpg=%u\n",
atomic_read(&net->n_lookup),
atomic_read(&net->n_reval),
atomic_read(&net->n_inval),
atomic_read(&net->n_relpg));
seq_printf(m, "dir-data: rdpg=%u\n",
atomic_read(&net->n_read_dir));
seq_printf(m, "dir-edit: cr=%u rm=%u\n",
atomic_read(&net->n_dir_cr),
atomic_read(&net->n_dir_rm));
seq_printf(m, "file-rd : n=%u nb=%lu\n",
atomic_read(&net->n_fetches),
atomic_long_read(&net->n_fetch_bytes));
seq_printf(m, "file-wr : n=%u nb=%lu\n",
atomic_read(&net->n_stores),
atomic_long_read(&net->n_store_bytes));
return 0;
}
/*
* initialise /proc/fs/afs/<cell>/
*/
int afs_proc_cell_setup(struct afs_cell *cell)
{
struct proc_dir_entry *dir;
struct afs_net *net = cell->net;
_enter("%p{%s},%p", cell, cell->name, net->proc_afs);
dir = proc_net_mkdir(net->net, cell->name, net->proc_afs);
if (!dir)
goto error_dir;
if (!proc_create_net_data("vlservers", 0444, dir,
&afs_proc_cell_vlservers_ops,
sizeof(struct seq_net_private),
cell) ||
!proc_create_net_data("volumes", 0444, dir,
&afs_proc_cell_volumes_ops,
sizeof(struct seq_net_private),
cell))
goto error_tree;
_leave(" = 0");
return 0;
error_tree:
remove_proc_subtree(cell->name, net->proc_afs);
error_dir:
_leave(" = -ENOMEM");
return -ENOMEM;
}
/*
* remove /proc/fs/afs/<cell>/
*/
void afs_proc_cell_remove(struct afs_cell *cell)
{
struct afs_net *net = cell->net;
_enter("");
remove_proc_subtree(cell->name, net->proc_afs);
_leave("");
}
/*
* initialise the /proc/fs/afs/ directory
*/
int afs_proc_init(struct afs_net *net)
{
struct proc_dir_entry *p;
_enter("");
p = proc_net_mkdir(net->net, "afs", net->net->proc_net);
if (!p)
goto error_dir;
if (!proc_create_net_data_write("cells", 0644, p,
&afs_proc_cells_ops,
afs_proc_cells_write,
sizeof(struct seq_net_private),
NULL) ||
!proc_create_net_single_write("rootcell", 0644, p,
afs_proc_rootcell_show,
afs_proc_rootcell_write,
NULL) ||
!proc_create_net("servers", 0444, p, &afs_proc_servers_ops,
sizeof(struct seq_net_private)) ||
!proc_create_net_single("stats", 0444, p, afs_proc_stats_show, NULL) ||
!proc_create_net_data_write("sysname", 0644, p,
&afs_proc_sysname_ops,
afs_proc_sysname_write,
sizeof(struct seq_net_private),
NULL))
goto error_tree;
net->proc_afs = p;
_leave(" = 0");
return 0;
error_tree:
proc_remove(p);
error_dir:
_leave(" = -ENOMEM");
return -ENOMEM;
}
/*
* clean up the /proc/fs/afs/ directory
*/
void afs_proc_cleanup(struct afs_net *net)
{
proc_remove(net->proc_afs);
net->proc_afs = NULL;
}