linux/drivers/w1/w1_netlink.c
David Fries 593ceb0c70 w1: fix netlink refcnt leak on error path
If the message type is W1_MASTER_CMD or W1_SLAVE_CMD, then a reference
is taken when searching for the slave or master device.  If there
isn't any following data m->len (mlen is a copy) is 0 and packing up
the message for later execution is skipped leaving nothing to
decrement the reference counts.

Way back when, m->len was checked before the search that increments the
reference count, but W1_LIST_MASTERS has no additional data, the check
was moved in 9be62e0b2f causing this bug.

This change reorders to put the check before the reference count is
incremented avoiding the problem.

Signed-off-by: David Fries <David@Fries.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-04-16 14:07:51 -07:00

607 lines
14 KiB
C

/*
* w1_netlink.c
*
* Copyright (c) 2003 Evgeniy Polyakov <zbr@ioremap.net>
*
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/connector.h>
#include "w1.h"
#include "w1_log.h"
#include "w1_netlink.h"
#if defined(CONFIG_W1_CON) && (defined(CONFIG_CONNECTOR) || (defined(CONFIG_CONNECTOR_MODULE) && defined(CONFIG_W1_MODULE)))
void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
{
char buf[sizeof(struct cn_msg) + sizeof(struct w1_netlink_msg)];
struct cn_msg *m = (struct cn_msg *)buf;
struct w1_netlink_msg *w = (struct w1_netlink_msg *)(m+1);
memset(buf, 0, sizeof(buf));
m->id.idx = CN_W1_IDX;
m->id.val = CN_W1_VAL;
m->seq = dev->seq++;
m->len = sizeof(struct w1_netlink_msg);
memcpy(w, msg, sizeof(struct w1_netlink_msg));
cn_netlink_send(m, dev->portid, 0, GFP_KERNEL);
}
static void w1_send_slave(struct w1_master *dev, u64 rn)
{
struct cn_msg *msg = dev->priv;
struct w1_netlink_msg *hdr = (struct w1_netlink_msg *)(msg + 1);
struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)(hdr + 1);
int avail;
u64 *data;
avail = dev->priv_size - cmd->len;
if (avail < 8) {
msg->ack++;
cn_netlink_send(msg, dev->portid, 0, GFP_KERNEL);
msg->len = sizeof(struct w1_netlink_msg) +
sizeof(struct w1_netlink_cmd);
hdr->len = sizeof(struct w1_netlink_cmd);
cmd->len = 0;
}
data = (void *)(cmd + 1) + cmd->len;
*data = rn;
cmd->len += 8;
hdr->len += 8;
msg->len += 8;
}
static void w1_found_send_slave(struct w1_master *dev, u64 rn)
{
/* update kernel slave list */
w1_slave_found(dev, rn);
w1_send_slave(dev, rn);
}
/* Get the current slave list, or search (with or without alarm) */
static int w1_get_slaves(struct w1_master *dev,
struct cn_msg *req_msg, struct w1_netlink_msg *req_hdr,
struct w1_netlink_cmd *req_cmd)
{
struct cn_msg *msg;
struct w1_netlink_msg *hdr;
struct w1_netlink_cmd *cmd;
struct w1_slave *sl;
msg = kzalloc(PAGE_SIZE, GFP_KERNEL);
if (!msg)
return -ENOMEM;
msg->id = req_msg->id;
msg->seq = req_msg->seq;
msg->ack = 0;
msg->len = sizeof(struct w1_netlink_msg) +
sizeof(struct w1_netlink_cmd);
hdr = (struct w1_netlink_msg *)(msg + 1);
cmd = (struct w1_netlink_cmd *)(hdr + 1);
hdr->type = W1_MASTER_CMD;
hdr->id = req_hdr->id;
hdr->len = sizeof(struct w1_netlink_cmd);
cmd->cmd = req_cmd->cmd;
cmd->len = 0;
dev->priv = msg;
dev->priv_size = PAGE_SIZE - msg->len - sizeof(struct cn_msg);
if (req_cmd->cmd == W1_CMD_LIST_SLAVES) {
__u64 rn;
mutex_lock(&dev->list_mutex);
list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
memcpy(&rn, &sl->reg_num, sizeof(rn));
w1_send_slave(dev, rn);
}
mutex_unlock(&dev->list_mutex);
} else {
w1_search_process_cb(dev, cmd->cmd == W1_CMD_ALARM_SEARCH ?
W1_ALARM_SEARCH : W1_SEARCH, w1_found_send_slave);
}
msg->ack = 0;
cn_netlink_send(msg, dev->portid, 0, GFP_KERNEL);
dev->priv = NULL;
dev->priv_size = 0;
kfree(msg);
return 0;
}
static int w1_send_read_reply(struct cn_msg *msg, struct w1_netlink_msg *hdr,
struct w1_netlink_cmd *cmd, u32 portid)
{
void *data;
struct w1_netlink_msg *h;
struct w1_netlink_cmd *c;
struct cn_msg *cm;
int err;
data = kzalloc(sizeof(struct cn_msg) +
sizeof(struct w1_netlink_msg) +
sizeof(struct w1_netlink_cmd) +
cmd->len, GFP_KERNEL);
if (!data)
return -ENOMEM;
cm = (struct cn_msg *)(data);
h = (struct w1_netlink_msg *)(cm + 1);
c = (struct w1_netlink_cmd *)(h + 1);
memcpy(cm, msg, sizeof(struct cn_msg));
memcpy(h, hdr, sizeof(struct w1_netlink_msg));
memcpy(c, cmd, sizeof(struct w1_netlink_cmd));
cm->ack = msg->seq+1;
cm->len = sizeof(struct w1_netlink_msg) +
sizeof(struct w1_netlink_cmd) + cmd->len;
h->len = sizeof(struct w1_netlink_cmd) + cmd->len;
memcpy(c->data, cmd->data, c->len);
err = cn_netlink_send(cm, portid, 0, GFP_KERNEL);
kfree(data);
return err;
}
static int w1_process_command_io(struct w1_master *dev, struct cn_msg *msg,
struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
{
int err = 0;
switch (cmd->cmd) {
case W1_CMD_TOUCH:
w1_touch_block(dev, cmd->data, cmd->len);
w1_send_read_reply(msg, hdr, cmd, dev->portid);
break;
case W1_CMD_READ:
w1_read_block(dev, cmd->data, cmd->len);
w1_send_read_reply(msg, hdr, cmd, dev->portid);
break;
case W1_CMD_WRITE:
w1_write_block(dev, cmd->data, cmd->len);
break;
default:
err = -EINVAL;
break;
}
return err;
}
static int w1_process_command_addremove(struct w1_master *dev,
struct cn_msg *msg, struct w1_netlink_msg *hdr,
struct w1_netlink_cmd *cmd)
{
struct w1_slave *sl;
int err = 0;
struct w1_reg_num *id;
if (cmd->len != 8)
return -EINVAL;
id = (struct w1_reg_num *)cmd->data;
sl = w1_slave_search_device(dev, id);
switch (cmd->cmd) {
case W1_CMD_SLAVE_ADD:
if (sl)
err = -EINVAL;
else
err = w1_attach_slave_device(dev, id);
break;
case W1_CMD_SLAVE_REMOVE:
if (sl)
w1_slave_detach(sl);
else
err = -EINVAL;
break;
default:
err = -EINVAL;
break;
}
return err;
}
static int w1_process_command_master(struct w1_master *dev,
struct cn_msg *req_msg, struct w1_netlink_msg *req_hdr,
struct w1_netlink_cmd *req_cmd)
{
int err = -EINVAL;
/* drop bus_mutex for search (does it's own locking), and add/remove
* which doesn't use the bus
*/
switch (req_cmd->cmd) {
case W1_CMD_SEARCH:
case W1_CMD_ALARM_SEARCH:
case W1_CMD_LIST_SLAVES:
mutex_unlock(&dev->bus_mutex);
err = w1_get_slaves(dev, req_msg, req_hdr, req_cmd);
mutex_lock(&dev->bus_mutex);
break;
case W1_CMD_READ:
case W1_CMD_WRITE:
case W1_CMD_TOUCH:
err = w1_process_command_io(dev, req_msg, req_hdr, req_cmd);
break;
case W1_CMD_RESET:
err = w1_reset_bus(dev);
break;
case W1_CMD_SLAVE_ADD:
case W1_CMD_SLAVE_REMOVE:
mutex_unlock(&dev->bus_mutex);
mutex_lock(&dev->mutex);
err = w1_process_command_addremove(dev, req_msg, req_hdr,
req_cmd);
mutex_unlock(&dev->mutex);
mutex_lock(&dev->bus_mutex);
break;
default:
err = -EINVAL;
break;
}
return err;
}
static int w1_process_command_slave(struct w1_slave *sl, struct cn_msg *msg,
struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
{
dev_dbg(&sl->master->dev, "%s: %02x.%012llx.%02x: cmd=%02x, len=%u.\n",
__func__, sl->reg_num.family, (unsigned long long)sl->reg_num.id,
sl->reg_num.crc, cmd->cmd, cmd->len);
return w1_process_command_io(sl->master, msg, hdr, cmd);
}
static int w1_process_command_root(struct cn_msg *msg,
struct w1_netlink_msg *mcmd, u32 portid)
{
struct w1_master *m;
struct cn_msg *cn;
struct w1_netlink_msg *w;
u32 *id;
cn = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!cn)
return -ENOMEM;
cn->id.idx = CN_W1_IDX;
cn->id.val = CN_W1_VAL;
cn->seq = msg->seq;
cn->ack = 1;
cn->len = sizeof(struct w1_netlink_msg);
w = (struct w1_netlink_msg *)(cn + 1);
w->type = W1_LIST_MASTERS;
w->status = 0;
w->len = 0;
id = (u32 *)(w + 1);
mutex_lock(&w1_mlock);
list_for_each_entry(m, &w1_masters, w1_master_entry) {
if (cn->len + sizeof(*id) > PAGE_SIZE - sizeof(struct cn_msg)) {
cn_netlink_send(cn, portid, 0, GFP_KERNEL);
cn->ack++;
cn->len = sizeof(struct w1_netlink_msg);
w->len = 0;
id = (u32 *)(w + 1);
}
*id = m->id;
w->len += sizeof(*id);
cn->len += sizeof(*id);
id++;
}
cn->ack = 0;
cn_netlink_send(cn, portid, 0, GFP_KERNEL);
mutex_unlock(&w1_mlock);
kfree(cn);
return 0;
}
static int w1_netlink_send_error(struct cn_msg *rcmsg, struct w1_netlink_msg *rmsg,
struct w1_netlink_cmd *rcmd, int portid, int error)
{
struct cn_msg *cmsg;
struct w1_netlink_msg *msg;
struct w1_netlink_cmd *cmd;
cmsg = kzalloc(sizeof(*msg) + sizeof(*cmd) + sizeof(*cmsg), GFP_KERNEL);
if (!cmsg)
return -ENOMEM;
msg = (struct w1_netlink_msg *)(cmsg + 1);
cmd = (struct w1_netlink_cmd *)(msg + 1);
memcpy(cmsg, rcmsg, sizeof(*cmsg));
cmsg->len = sizeof(*msg);
memcpy(msg, rmsg, sizeof(*msg));
msg->len = 0;
msg->status = (short)-error;
if (rcmd) {
memcpy(cmd, rcmd, sizeof(*cmd));
cmd->len = 0;
msg->len += sizeof(*cmd);
cmsg->len += sizeof(*cmd);
}
error = cn_netlink_send(cmsg, portid, 0, GFP_KERNEL);
kfree(cmsg);
return error;
}
/* Bundle together a reference count, the full message, and broken out
* commands to be executed on each w1 master kthread in one memory allocation.
*/
struct w1_cb_block {
atomic_t refcnt;
u32 portid; /* Sending process port ID */
struct cn_msg msg;
/* cn_msg data */
/* one or more variable length struct w1_cb_node */
};
struct w1_cb_node {
struct w1_async_cmd async;
/* pointers within w1_cb_block and msg data */
struct w1_cb_block *block;
struct w1_netlink_msg *m;
struct w1_slave *sl;
struct w1_master *dev;
};
static void w1_process_cb(struct w1_master *dev, struct w1_async_cmd *async_cmd)
{
struct w1_cb_node *node = container_of(async_cmd, struct w1_cb_node,
async);
u16 mlen = node->m->len;
u8 *cmd_data = node->m->data;
int err = 0;
struct w1_slave *sl = node->sl;
struct w1_netlink_cmd *cmd = NULL;
mutex_lock(&dev->bus_mutex);
dev->portid = node->block->portid;
if (sl && w1_reset_select_slave(sl))
err = -ENODEV;
while (mlen && !err) {
cmd = (struct w1_netlink_cmd *)cmd_data;
if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) {
err = -E2BIG;
break;
}
if (sl)
err = w1_process_command_slave(sl, &node->block->msg,
node->m, cmd);
else
err = w1_process_command_master(dev, &node->block->msg,
node->m, cmd);
w1_netlink_send_error(&node->block->msg, node->m, cmd,
node->block->portid, err);
err = 0;
cmd_data += cmd->len + sizeof(struct w1_netlink_cmd);
mlen -= cmd->len + sizeof(struct w1_netlink_cmd);
}
if (!cmd || err)
w1_netlink_send_error(&node->block->msg, node->m, cmd,
node->block->portid, err);
/* ref taken in w1_search_slave or w1_search_master_id when building
* the block
*/
if (sl)
w1_unref_slave(sl);
else
atomic_dec(&dev->refcnt);
dev->portid = 0;
mutex_unlock(&dev->bus_mutex);
mutex_lock(&dev->list_mutex);
list_del(&async_cmd->async_entry);
mutex_unlock(&dev->list_mutex);
if (atomic_sub_return(1, &node->block->refcnt) == 0)
kfree(node->block);
}
static void w1_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
{
struct w1_netlink_msg *m = (struct w1_netlink_msg *)(msg + 1);
struct w1_slave *sl;
struct w1_master *dev;
u16 msg_len;
int err = 0;
struct w1_cb_block *block = NULL;
struct w1_cb_node *node = NULL;
int node_count = 0;
/* Count the number of master or slave commands there are to allocate
* space for one cb_node each.
*/
msg_len = msg->len;
while (msg_len && !err) {
if (m->len + sizeof(struct w1_netlink_msg) > msg_len) {
err = -E2BIG;
break;
}
if (m->type == W1_MASTER_CMD || m->type == W1_SLAVE_CMD)
++node_count;
msg_len -= sizeof(struct w1_netlink_msg) + m->len;
m = (struct w1_netlink_msg *)(((u8 *)m) +
sizeof(struct w1_netlink_msg) + m->len);
}
m = (struct w1_netlink_msg *)(msg + 1);
if (node_count) {
/* msg->len doesn't include itself */
long size = sizeof(struct w1_cb_block) + msg->len +
node_count*sizeof(struct w1_cb_node);
block = kmalloc(size, GFP_KERNEL);
if (!block) {
w1_netlink_send_error(msg, m, NULL, nsp->portid,
-ENOMEM);
return;
}
atomic_set(&block->refcnt, 1);
block->portid = nsp->portid;
memcpy(&block->msg, msg, sizeof(*msg) + msg->len);
node = (struct w1_cb_node *)((u8 *)block->msg.data + msg->len);
}
msg_len = msg->len;
while (msg_len && !err) {
dev = NULL;
sl = NULL;
if (m->len + sizeof(struct w1_netlink_msg) > msg_len) {
err = -E2BIG;
break;
}
/* execute on this thread, no need to process later */
if (m->type == W1_LIST_MASTERS) {
err = w1_process_command_root(msg, m, nsp->portid);
goto out_cont;
}
/* All following message types require additional data,
* check here before references are taken.
*/
if (!m->len) {
err = -EPROTO;
goto out_cont;
}
/* both search calls take reference counts */
if (m->type == W1_MASTER_CMD) {
dev = w1_search_master_id(m->id.mst.id);
} else if (m->type == W1_SLAVE_CMD) {
sl = w1_search_slave((struct w1_reg_num *)m->id.id);
if (sl)
dev = sl->master;
} else {
printk(KERN_NOTICE
"%s: msg: %x.%x, wrong type: %u, len: %u.\n",
__func__, msg->id.idx, msg->id.val,
m->type, m->len);
err = -EPROTO;
goto out_cont;
}
if (!dev) {
err = -ENODEV;
goto out_cont;
}
err = 0;
atomic_inc(&block->refcnt);
node->async.cb = w1_process_cb;
node->block = block;
node->m = (struct w1_netlink_msg *)((u8 *)&block->msg +
(size_t)((u8 *)m - (u8 *)msg));
node->sl = sl;
node->dev = dev;
mutex_lock(&dev->list_mutex);
list_add_tail(&node->async.async_entry, &dev->async_list);
wake_up_process(dev->thread);
mutex_unlock(&dev->list_mutex);
++node;
out_cont:
if (err)
w1_netlink_send_error(msg, m, NULL, nsp->portid, err);
msg_len -= sizeof(struct w1_netlink_msg) + m->len;
m = (struct w1_netlink_msg *)(((u8 *)m) +
sizeof(struct w1_netlink_msg) + m->len);
/*
* Let's allow requests for nonexisting devices.
*/
if (err == -ENODEV)
err = 0;
}
if (block && atomic_sub_return(1, &block->refcnt) == 0)
kfree(block);
}
int w1_init_netlink(void)
{
struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
return cn_add_callback(&w1_id, "w1", &w1_cn_callback);
}
void w1_fini_netlink(void)
{
struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
cn_del_callback(&w1_id);
}
#else
void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
{
}
int w1_init_netlink(void)
{
return 0;
}
void w1_fini_netlink(void)
{
}
#endif