linux/net/atm/proc.c
Dan Rosenberg 71338aa7d0 net: convert %p usage to %pK
The %pK format specifier is designed to hide exposed kernel pointers,
specifically via /proc interfaces.  Exposing these pointers provides an
easy target for kernel write vulnerabilities, since they reveal the
locations of writable structures containing easily triggerable function
pointers.  The behavior of %pK depends on the kptr_restrict sysctl.

If kptr_restrict is set to 0, no deviation from the standard %p behavior
occurs.  If kptr_restrict is set to 1, the default, if the current user
(intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG
(currently in the LSM tree), kernel pointers using %pK are printed as 0's.
 If kptr_restrict is set to 2, kernel pointers using %pK are printed as
0's regardless of privileges.  Replacing with 0's was chosen over the
default "(null)", which cannot be parsed by userland %p, which expects
"(nil)".

The supporting code for kptr_restrict and %pK are currently in the -mm
tree.  This patch converts users of %p in net/ to %pK.  Cases of printing
pointers to the syslog are not covered, since this would eliminate useful
information for postmortem debugging and the reading of the syslog is
already optionally protected by the dmesg_restrict sysctl.

Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: James Morris <jmorris@namei.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Thomas Graf <tgraf@infradead.org>
Cc: Eugene Teo <eugeneteo@kernel.org>
Cc: Kees Cook <kees.cook@canonical.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Eric Paris <eparis@parisplace.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-24 01:13:12 -04:00

498 lines
12 KiB
C

/* net/atm/proc.c - ATM /proc interface
*
* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA
*
* seq_file api usage by romieu@fr.zoreil.com
*
* Evaluating the efficiency of the whole thing if left as an exercise to
* the reader.
*/
#include <linux/module.h> /* for EXPORT_SYMBOL */
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/errno.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/netdevice.h>
#include <linux/atmclip.h>
#include <linux/init.h> /* for __init */
#include <linux/slab.h>
#include <net/net_namespace.h>
#include <net/atmclip.h>
#include <linux/uaccess.h>
#include <linux/param.h> /* for HZ */
#include <asm/atomic.h>
#include "resources.h"
#include "common.h" /* atm_proc_init prototype */
#include "signaling.h" /* to get sigd - ugly too */
static ssize_t proc_dev_atm_read(struct file *file, char __user *buf,
size_t count, loff_t *pos);
static const struct file_operations proc_atm_dev_ops = {
.owner = THIS_MODULE,
.read = proc_dev_atm_read,
.llseek = noop_llseek,
};
static void add_stats(struct seq_file *seq, const char *aal,
const struct k_atm_aal_stats *stats)
{
seq_printf(seq, "%s ( %d %d %d %d %d )", aal,
atomic_read(&stats->tx), atomic_read(&stats->tx_err),
atomic_read(&stats->rx), atomic_read(&stats->rx_err),
atomic_read(&stats->rx_drop));
}
static void atm_dev_info(struct seq_file *seq, const struct atm_dev *dev)
{
int i;
seq_printf(seq, "%3d %-8s", dev->number, dev->type);
for (i = 0; i < ESI_LEN; i++)
seq_printf(seq, "%02x", dev->esi[i]);
seq_puts(seq, " ");
add_stats(seq, "0", &dev->stats.aal0);
seq_puts(seq, " ");
add_stats(seq, "5", &dev->stats.aal5);
seq_printf(seq, "\t[%d]", atomic_read(&dev->refcnt));
seq_putc(seq, '\n');
}
struct vcc_state {
int bucket;
struct sock *sk;
int family;
};
static inline int compare_family(struct sock *sk, int family)
{
return !family || (sk->sk_family == family);
}
static int __vcc_walk(struct sock **sock, int family, int *bucket, loff_t l)
{
struct sock *sk = *sock;
if (sk == SEQ_START_TOKEN) {
for (*bucket = 0; *bucket < VCC_HTABLE_SIZE; ++*bucket) {
struct hlist_head *head = &vcc_hash[*bucket];
sk = hlist_empty(head) ? NULL : __sk_head(head);
if (sk)
break;
}
l--;
}
try_again:
for (; sk; sk = sk_next(sk)) {
l -= compare_family(sk, family);
if (l < 0)
goto out;
}
if (!sk && ++*bucket < VCC_HTABLE_SIZE) {
sk = sk_head(&vcc_hash[*bucket]);
goto try_again;
}
sk = SEQ_START_TOKEN;
out:
*sock = sk;
return (l < 0);
}
static inline void *vcc_walk(struct vcc_state *state, loff_t l)
{
return __vcc_walk(&state->sk, state->family, &state->bucket, l) ?
state : NULL;
}
static int __vcc_seq_open(struct inode *inode, struct file *file,
int family, const struct seq_operations *ops)
{
struct vcc_state *state;
state = __seq_open_private(file, ops, sizeof(*state));
if (state == NULL)
return -ENOMEM;
state->family = family;
return 0;
}
static void *vcc_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(vcc_sklist_lock)
{
struct vcc_state *state = seq->private;
loff_t left = *pos;
read_lock(&vcc_sklist_lock);
state->sk = SEQ_START_TOKEN;
return left ? vcc_walk(state, left) : SEQ_START_TOKEN;
}
static void vcc_seq_stop(struct seq_file *seq, void *v)
__releases(vcc_sklist_lock)
{
read_unlock(&vcc_sklist_lock);
}
static void *vcc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct vcc_state *state = seq->private;
v = vcc_walk(state, 1);
*pos += !!PTR_ERR(v);
return v;
}
static void pvc_info(struct seq_file *seq, struct atm_vcc *vcc)
{
static const char *const class_name[] = {
"off", "UBR", "CBR", "VBR", "ABR"};
static const char *const aal_name[] = {
"---", "1", "2", "3/4", /* 0- 3 */
"???", "5", "???", "???", /* 4- 7 */
"???", "???", "???", "???", /* 8-11 */
"???", "0", "???", "???"}; /* 12-15 */
seq_printf(seq, "%3d %3d %5d %-3s %7d %-5s %7d %-6s",
vcc->dev->number, vcc->vpi, vcc->vci,
vcc->qos.aal >= ARRAY_SIZE(aal_name) ? "err" :
aal_name[vcc->qos.aal], vcc->qos.rxtp.min_pcr,
class_name[vcc->qos.rxtp.traffic_class],
vcc->qos.txtp.min_pcr,
class_name[vcc->qos.txtp.traffic_class]);
if (test_bit(ATM_VF_IS_CLIP, &vcc->flags)) {
struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
struct net_device *dev;
dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : NULL;
seq_printf(seq, "CLIP, Itf:%s, Encap:",
dev ? dev->name : "none?");
seq_printf(seq, "%s", clip_vcc->encap ? "LLC/SNAP" : "None");
}
seq_putc(seq, '\n');
}
static const char *vcc_state(struct atm_vcc *vcc)
{
static const char *const map[] = { ATM_VS2TXT_MAP };
return map[ATM_VF2VS(vcc->flags)];
}
static void vcc_info(struct seq_file *seq, struct atm_vcc *vcc)
{
struct sock *sk = sk_atm(vcc);
seq_printf(seq, "%pK ", vcc);
if (!vcc->dev)
seq_printf(seq, "Unassigned ");
else
seq_printf(seq, "%3d %3d %5d ", vcc->dev->number, vcc->vpi,
vcc->vci);
switch (sk->sk_family) {
case AF_ATMPVC:
seq_printf(seq, "PVC");
break;
case AF_ATMSVC:
seq_printf(seq, "SVC");
break;
default:
seq_printf(seq, "%3d", sk->sk_family);
}
seq_printf(seq, " %04lx %5d %7d/%7d %7d/%7d [%d]\n",
vcc->flags, sk->sk_err,
sk_wmem_alloc_get(sk), sk->sk_sndbuf,
sk_rmem_alloc_get(sk), sk->sk_rcvbuf,
atomic_read(&sk->sk_refcnt));
}
static void svc_info(struct seq_file *seq, struct atm_vcc *vcc)
{
if (!vcc->dev)
seq_printf(seq, sizeof(void *) == 4 ?
"N/A@%pK%10s" : "N/A@%pK%2s", vcc, "");
else
seq_printf(seq, "%3d %3d %5d ",
vcc->dev->number, vcc->vpi, vcc->vci);
seq_printf(seq, "%-10s ", vcc_state(vcc));
seq_printf(seq, "%s%s", vcc->remote.sas_addr.pub,
*vcc->remote.sas_addr.pub && *vcc->remote.sas_addr.prv ? "+" : "");
if (*vcc->remote.sas_addr.prv) {
int i;
for (i = 0; i < ATM_ESA_LEN; i++)
seq_printf(seq, "%02x", vcc->remote.sas_addr.prv[i]);
}
seq_putc(seq, '\n');
}
static int atm_dev_seq_show(struct seq_file *seq, void *v)
{
static char atm_dev_banner[] =
"Itf Type ESI/\"MAC\"addr "
"AAL(TX,err,RX,err,drop) ... [refcnt]\n";
if (v == &atm_devs)
seq_puts(seq, atm_dev_banner);
else {
struct atm_dev *dev = list_entry(v, struct atm_dev, dev_list);
atm_dev_info(seq, dev);
}
return 0;
}
static const struct seq_operations atm_dev_seq_ops = {
.start = atm_dev_seq_start,
.next = atm_dev_seq_next,
.stop = atm_dev_seq_stop,
.show = atm_dev_seq_show,
};
static int atm_dev_seq_open(struct inode *inode, struct file *file)
{
return seq_open(file, &atm_dev_seq_ops);
}
static const struct file_operations devices_seq_fops = {
.open = atm_dev_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int pvc_seq_show(struct seq_file *seq, void *v)
{
static char atm_pvc_banner[] =
"Itf VPI VCI AAL RX(PCR,Class) TX(PCR,Class)\n";
if (v == SEQ_START_TOKEN)
seq_puts(seq, atm_pvc_banner);
else {
struct vcc_state *state = seq->private;
struct atm_vcc *vcc = atm_sk(state->sk);
pvc_info(seq, vcc);
}
return 0;
}
static const struct seq_operations pvc_seq_ops = {
.start = vcc_seq_start,
.next = vcc_seq_next,
.stop = vcc_seq_stop,
.show = pvc_seq_show,
};
static int pvc_seq_open(struct inode *inode, struct file *file)
{
return __vcc_seq_open(inode, file, PF_ATMPVC, &pvc_seq_ops);
}
static const struct file_operations pvc_seq_fops = {
.open = pvc_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static int vcc_seq_show(struct seq_file *seq, void *v)
{
if (v == SEQ_START_TOKEN) {
seq_printf(seq, sizeof(void *) == 4 ? "%-8s%s" : "%-16s%s",
"Address ", "Itf VPI VCI Fam Flags Reply "
"Send buffer Recv buffer [refcnt]\n");
} else {
struct vcc_state *state = seq->private;
struct atm_vcc *vcc = atm_sk(state->sk);
vcc_info(seq, vcc);
}
return 0;
}
static const struct seq_operations vcc_seq_ops = {
.start = vcc_seq_start,
.next = vcc_seq_next,
.stop = vcc_seq_stop,
.show = vcc_seq_show,
};
static int vcc_seq_open(struct inode *inode, struct file *file)
{
return __vcc_seq_open(inode, file, 0, &vcc_seq_ops);
}
static const struct file_operations vcc_seq_fops = {
.open = vcc_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static int svc_seq_show(struct seq_file *seq, void *v)
{
static const char atm_svc_banner[] =
"Itf VPI VCI State Remote\n";
if (v == SEQ_START_TOKEN)
seq_puts(seq, atm_svc_banner);
else {
struct vcc_state *state = seq->private;
struct atm_vcc *vcc = atm_sk(state->sk);
svc_info(seq, vcc);
}
return 0;
}
static const struct seq_operations svc_seq_ops = {
.start = vcc_seq_start,
.next = vcc_seq_next,
.stop = vcc_seq_stop,
.show = svc_seq_show,
};
static int svc_seq_open(struct inode *inode, struct file *file)
{
return __vcc_seq_open(inode, file, PF_ATMSVC, &svc_seq_ops);
}
static const struct file_operations svc_seq_fops = {
.open = svc_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static ssize_t proc_dev_atm_read(struct file *file, char __user *buf,
size_t count, loff_t *pos)
{
struct atm_dev *dev;
unsigned long page;
int length;
if (count == 0)
return 0;
page = get_zeroed_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
dev = PDE(file->f_path.dentry->d_inode)->data;
if (!dev->ops->proc_read)
length = -EINVAL;
else {
length = dev->ops->proc_read(dev, pos, (char *)page);
if (length > count)
length = -EINVAL;
}
if (length >= 0) {
if (copy_to_user(buf, (char *)page, length))
length = -EFAULT;
(*pos)++;
}
free_page(page);
return length;
}
struct proc_dir_entry *atm_proc_root;
EXPORT_SYMBOL(atm_proc_root);
int atm_proc_dev_register(struct atm_dev *dev)
{
int error;
/* No proc info */
if (!dev->ops->proc_read)
return 0;
error = -ENOMEM;
dev->proc_name = kasprintf(GFP_KERNEL, "%s:%d", dev->type, dev->number);
if (!dev->proc_name)
goto err_out;
dev->proc_entry = proc_create_data(dev->proc_name, 0, atm_proc_root,
&proc_atm_dev_ops, dev);
if (!dev->proc_entry)
goto err_free_name;
return 0;
err_free_name:
kfree(dev->proc_name);
err_out:
return error;
}
void atm_proc_dev_deregister(struct atm_dev *dev)
{
if (!dev->ops->proc_read)
return;
remove_proc_entry(dev->proc_name, atm_proc_root);
kfree(dev->proc_name);
}
static struct atm_proc_entry {
char *name;
const struct file_operations *proc_fops;
struct proc_dir_entry *dirent;
} atm_proc_ents[] = {
{ .name = "devices", .proc_fops = &devices_seq_fops },
{ .name = "pvc", .proc_fops = &pvc_seq_fops },
{ .name = "svc", .proc_fops = &svc_seq_fops },
{ .name = "vc", .proc_fops = &vcc_seq_fops },
{ .name = NULL, .proc_fops = NULL }
};
static void atm_proc_dirs_remove(void)
{
static struct atm_proc_entry *e;
for (e = atm_proc_ents; e->name; e++) {
if (e->dirent)
remove_proc_entry(e->name, atm_proc_root);
}
proc_net_remove(&init_net, "atm");
}
int __init atm_proc_init(void)
{
static struct atm_proc_entry *e;
int ret;
atm_proc_root = proc_net_mkdir(&init_net, "atm", init_net.proc_net);
if (!atm_proc_root)
goto err_out;
for (e = atm_proc_ents; e->name; e++) {
struct proc_dir_entry *dirent;
dirent = proc_create(e->name, S_IRUGO,
atm_proc_root, e->proc_fops);
if (!dirent)
goto err_out_remove;
e->dirent = dirent;
}
ret = 0;
out:
return ret;
err_out_remove:
atm_proc_dirs_remove();
err_out:
ret = -ENOMEM;
goto out;
}
void atm_proc_exit(void)
{
atm_proc_dirs_remove();
}