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linux-hardened/net/atm/signaling.c
Stefan Hajnoczi c685293aa3 net/atm: sk_err_soft must be positive 
The sk_err and sk_err_soft fields are positive errno values and
userspace applications rely on this when using getsockopt(SO_ERROR).

ATM code places an -errno into sk_err_soft in sigd_send() and returns it
from svc_addparty()/svc_dropparty().

Although I am not familiar with ATM code I came to this conclusion
because:

1. sigd_send() msg->type cases as_okay and as_error both have:

   sk->sk_err = -msg->reply;

   while the as_addparty and as_dropparty cases have:

   sk->sk_err_soft = msg->reply;

   This is the source of the inconsistency.

2. svc_addparty() returns an -errno and assumes sk_err_soft is also an
   -errno:

       if (flags & O_NONBLOCK) {
           error = -EINPROGRESS;
           goto out;
       }
       ...
       error = xchg(&sk->sk_err_soft, 0);
   out:
       release_sock(sk);
       return error;

   This shows that sk_err_soft is indeed being treated as an -errno.

This patch ensures that sk_err_soft is always a positive errno.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-23 13:51:10 -07:00

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/* net/atm/signaling.c - ATM signaling */
/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
#include <linux/errno.h> /* error codes */
#include <linux/kernel.h> /* printk */
#include <linux/skbuff.h>
#include <linux/wait.h>
#include <linux/sched.h> /* jiffies and HZ */
#include <linux/atm.h> /* ATM stuff */
#include <linux/atmsap.h>
#include <linux/atmsvc.h>
#include <linux/atmdev.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include "resources.h"
#include "signaling.h"
struct atm_vcc *sigd = NULL;
static void sigd_put_skb(struct sk_buff *skb)
{
if (!sigd) {
pr_debug("atmsvc: no signaling daemon\n");
kfree_skb(skb);
return;
}
atm_force_charge(sigd, skb->truesize);
skb_queue_tail(&sk_atm(sigd)->sk_receive_queue, skb);
sk_atm(sigd)->sk_data_ready(sk_atm(sigd));
}
static void modify_qos(struct atm_vcc *vcc, struct atmsvc_msg *msg)
{
struct sk_buff *skb;
if (test_bit(ATM_VF_RELEASED, &vcc->flags) ||
!test_bit(ATM_VF_READY, &vcc->flags))
return;
msg->type = as_error;
if (!vcc->dev->ops->change_qos)
msg->reply = -EOPNOTSUPP;
else {
/* should lock VCC */
msg->reply = vcc->dev->ops->change_qos(vcc, &msg->qos,
msg->reply);
if (!msg->reply)
msg->type = as_okay;
}
/*
* Should probably just turn around the old skb. But the, the buffer
* space accounting needs to follow the change too. Maybe later.
*/
while (!(skb = alloc_skb(sizeof(struct atmsvc_msg), GFP_KERNEL)))
schedule();
*(struct atmsvc_msg *)skb_put(skb, sizeof(struct atmsvc_msg)) = *msg;
sigd_put_skb(skb);
}
static int sigd_send(struct atm_vcc *vcc, struct sk_buff *skb)
{
struct atmsvc_msg *msg;
struct atm_vcc *session_vcc;
struct sock *sk;
msg = (struct atmsvc_msg *) skb->data;
atomic_sub(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
vcc = *(struct atm_vcc **) &msg->vcc;
pr_debug("%d (0x%lx)\n", (int)msg->type, (unsigned long)vcc);
sk = sk_atm(vcc);
switch (msg->type) {
case as_okay:
sk->sk_err = -msg->reply;
clear_bit(ATM_VF_WAITING, &vcc->flags);
if (!*vcc->local.sas_addr.prv && !*vcc->local.sas_addr.pub) {
vcc->local.sas_family = AF_ATMSVC;
memcpy(vcc->local.sas_addr.prv,
msg->local.sas_addr.prv, ATM_ESA_LEN);
memcpy(vcc->local.sas_addr.pub,
msg->local.sas_addr.pub, ATM_E164_LEN + 1);
}
session_vcc = vcc->session ? vcc->session : vcc;
if (session_vcc->vpi || session_vcc->vci)
break;
session_vcc->itf = msg->pvc.sap_addr.itf;
session_vcc->vpi = msg->pvc.sap_addr.vpi;
session_vcc->vci = msg->pvc.sap_addr.vci;
if (session_vcc->vpi || session_vcc->vci)
session_vcc->qos = msg->qos;
break;
case as_error:
clear_bit(ATM_VF_REGIS, &vcc->flags);
clear_bit(ATM_VF_READY, &vcc->flags);
sk->sk_err = -msg->reply;
clear_bit(ATM_VF_WAITING, &vcc->flags);
break;
case as_indicate:
vcc = *(struct atm_vcc **)&msg->listen_vcc;
sk = sk_atm(vcc);
pr_debug("as_indicate!!!\n");
lock_sock(sk);
if (sk_acceptq_is_full(sk)) {
sigd_enq(NULL, as_reject, vcc, NULL, NULL);
dev_kfree_skb(skb);
goto as_indicate_complete;
}
sk->sk_ack_backlog++;
skb_queue_tail(&sk->sk_receive_queue, skb);
pr_debug("waking sk_sleep(sk) 0x%p\n", sk_sleep(sk));
sk->sk_state_change(sk);
as_indicate_complete:
release_sock(sk);
return 0;
case as_close:
set_bit(ATM_VF_RELEASED, &vcc->flags);
vcc_release_async(vcc, msg->reply);
goto out;
case as_modify:
modify_qos(vcc, msg);
break;
case as_addparty:
case as_dropparty:
sk->sk_err_soft = -msg->reply;
/* < 0 failure, otherwise ep_ref */
clear_bit(ATM_VF_WAITING, &vcc->flags);
break;
default:
pr_alert("bad message type %d\n", (int)msg->type);
return -EINVAL;
}
sk->sk_state_change(sk);
out:
dev_kfree_skb(skb);
return 0;
}
void sigd_enq2(struct atm_vcc *vcc, enum atmsvc_msg_type type,
struct atm_vcc *listen_vcc, const struct sockaddr_atmpvc *pvc,
const struct sockaddr_atmsvc *svc, const struct atm_qos *qos,
int reply)
{
struct sk_buff *skb;
struct atmsvc_msg *msg;
static unsigned int session = 0;
pr_debug("%d (0x%p)\n", (int)type, vcc);
while (!(skb = alloc_skb(sizeof(struct atmsvc_msg), GFP_KERNEL)))
schedule();
msg = (struct atmsvc_msg *)skb_put(skb, sizeof(struct atmsvc_msg));
memset(msg, 0, sizeof(*msg));
msg->type = type;
*(struct atm_vcc **) &msg->vcc = vcc;
*(struct atm_vcc **) &msg->listen_vcc = listen_vcc;
msg->reply = reply;
if (qos)
msg->qos = *qos;
if (vcc)
msg->sap = vcc->sap;
if (svc)
msg->svc = *svc;
if (vcc)
msg->local = vcc->local;
if (pvc)
msg->pvc = *pvc;
if (vcc) {
if (type == as_connect && test_bit(ATM_VF_SESSION, &vcc->flags))
msg->session = ++session;
/* every new pmp connect gets the next session number */
}
sigd_put_skb(skb);
if (vcc)
set_bit(ATM_VF_REGIS, &vcc->flags);
}
void sigd_enq(struct atm_vcc *vcc, enum atmsvc_msg_type type,
struct atm_vcc *listen_vcc, const struct sockaddr_atmpvc *pvc,
const struct sockaddr_atmsvc *svc)
{
sigd_enq2(vcc, type, listen_vcc, pvc, svc, vcc ? &vcc->qos : NULL, 0);
/* other ISP applications may use "reply" */
}
static void purge_vcc(struct atm_vcc *vcc)
{
if (sk_atm(vcc)->sk_family == PF_ATMSVC &&
!test_bit(ATM_VF_META, &vcc->flags)) {
set_bit(ATM_VF_RELEASED, &vcc->flags);
clear_bit(ATM_VF_REGIS, &vcc->flags);
vcc_release_async(vcc, -EUNATCH);
}
}
static void sigd_close(struct atm_vcc *vcc)
{
struct sock *s;
int i;
pr_debug("\n");
sigd = NULL;
if (skb_peek(&sk_atm(vcc)->sk_receive_queue))
pr_err("closing with requests pending\n");
skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
read_lock(&vcc_sklist_lock);
for (i = 0; i < VCC_HTABLE_SIZE; ++i) {
struct hlist_head *head = &vcc_hash[i];
sk_for_each(s, head) {
vcc = atm_sk(s);
purge_vcc(vcc);
}
}
read_unlock(&vcc_sklist_lock);
}
static struct atmdev_ops sigd_dev_ops = {
.close = sigd_close,
.send = sigd_send
};
static struct atm_dev sigd_dev = {
.ops = &sigd_dev_ops,
.type = "sig",
.number = 999,
.lock = __SPIN_LOCK_UNLOCKED(sigd_dev.lock)
};
int sigd_attach(struct atm_vcc *vcc)
{
if (sigd)
return -EADDRINUSE;
pr_debug("\n");
sigd = vcc;
vcc->dev = &sigd_dev;
vcc_insert_socket(sk_atm(vcc));
set_bit(ATM_VF_META, &vcc->flags);
set_bit(ATM_VF_READY, &vcc->flags);
return 0;
}
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