[PATCH AUTOSEL 5.3 108/203] media: dvb-frontends: use ida for pll number

Sasha Levin
2019-09-22T19:34:50Z

From: Sean Young <sean@mess.org>

[ Upstream commit c268e7adea52be0093de1164c425f3c8d8927770 ]

KASAN: global-out-of-bounds Read in dvb_pll_attach

Syzbot reported global-out-of-bounds Read in dvb_pll_attach, while
accessing id[dvb_pll_devcount], because dvb_pll_devcount was 65,
that is more than size of 'id' which is DVB_PLL_MAX(64).

Rather than increasing dvb_pll_devcount every time, use ida so that
numbers are allocated correctly. This does mean that no more than
64 devices can be attached at the same time, but this is more than
sufficient.

usb 1-1: dvb_usb_v2: will pass the complete MPEG2 transport stream to the
software demuxer
dvbdev: DVB: registering new adapter (774 Friio White ISDB-T USB2.0)
usb 1-1: media controller created
dvbdev: dvb_create_media_entity: media entity 'dvb-demux' registered.
tc90522 0-0018: Toshiba TC90522 attached.
usb 1-1: DVB: registering adapter 0 frontend 0 (Toshiba TC90522 ISDB-T
module)...
dvbdev: dvb_create_media_entity: media entity 'Toshiba TC90522 ISDB-T
module' registered.
==================================================================
BUG: KASAN: global-out-of-bounds in dvb_pll_attach+0x6c5/0x830
drivers/media/dvb-frontends/dvb-pll.c:798
Read of size 4 at addr ffffffff89c9e5e0 by task kworker/0:1/12

CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.2.0-rc6+ #13
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description+0x67/0x231 mm/kasan/report.c:188
__kasan_report.cold+0x1a/0x32 mm/kasan/report.c:317
kasan_report+0xe/0x20 mm/kasan/common.c:614
dvb_pll_attach+0x6c5/0x830 drivers/media/dvb-frontends/dvb-pll.c:798
dvb_pll_probe+0xfe/0x174 drivers/media/dvb-frontends/dvb-pll.c:877
i2c_device_probe+0x790/0xaa0 drivers/i2c/i2c-core-base.c:389
really_probe+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
i2c_new_client_device+0x5b3/0xc40 drivers/i2c/i2c-core-base.c:778
i2c_new_device+0x19/0x50 drivers/i2c/i2c-core-base.c:821
dvb_module_probe+0xf9/0x220 drivers/media/dvb-core/dvbdev.c:985
friio_tuner_attach+0x125/0x1d0 drivers/media/usb/dvb-usb-v2/gl861.c:536
dvb_usbv2_adapter_frontend_init
drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:675 [inline]
dvb_usbv2_adapter_init drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:804
[inline]
dvb_usbv2_init drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:865 [inline]
dvb_usbv2_probe.cold+0x24dc/0x255d
drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:980
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
really_probe+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
usb_new_device.cold+0x8c1/0x1016 drivers/usb/core/hub.c:2534
hub_port_connect drivers/usb/core/hub.c:5089 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
port_event drivers/usb/core/hub.c:5350 [inline]
hub_event+0x1ada/0x3590 drivers/usb/core/hub.c:5432
process_one_work+0x905/0x1570 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x30b/0x410 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the variable:
id+0x100/0x120

Memory state around the buggy address:
ffffffff89c9e480: fa fa fa fa 00 00 fa fa fa fa fa fa 00 00 00 00
ffffffff89c9e500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffffffff89c9e580: 00 00 00 00 00 00 00 00 00 00 00 00 fa fa fa fa
^
ffffffff89c9e600: 04 fa fa fa fa fa fa fa 04 fa fa fa fa fa fa fa
ffffffff89c9e680: 04 fa fa fa fa fa fa fa 04 fa fa fa fa fa fa fa
==================================================================

Reported-by: syzbot+8a8f48672560c8ca59dd@syzkaller.appspotmail.com
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/dvb-frontends/dvb-pll.c | 40 ++++++++++++++++-----------
1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/drivers/media/dvb-frontends/dvb-pll.c b/drivers/media/dvb-frontends/dvb-pll.c
index ba0c49107bd28..d45b4ddc8f912 100644
--- a/drivers/media/dvb-frontends/dvb-pll.c
+++ b/drivers/media/dvb-frontends/dvb-pll.c
@@ -9,6 +9,7 @@

#include <linux/slab.h>
#include <linux/module.h>
+#include <linux/idr.h>
#include <linux/dvb/frontend.h>
#include <asm/types.h>

@@ -34,8 +35,7 @@ struct dvb_pll_priv {
};

#define DVB_PLL_MAX 64
-
-static unsigned int dvb_pll_devcount;
+static DEFINE_IDA(pll_ida);

static int debug;
module_param(debug, int, 0644);
@@ -787,6 +787,7 @@ struct dvb_frontend *dvb_pll_attach(struct dvb_frontend *fe, int pll_addr,
struct dvb_pll_priv *priv = NULL;
int ret;
const struct dvb_pll_desc *desc;
+ int nr;

b1 = kmalloc(1, GFP_KERNEL);
if (!b1)
@@ -795,9 +796,14 @@ struct dvb_frontend *dvb_pll_attach(struct dvb_frontend *fe, int pll_addr,
b1[0] = 0;
msg.buf = b1;

- if ((id[dvb_pll_devcount] > DVB_PLL_UNDEFINED) &&
- (id[dvb_pll_devcount] < ARRAY_SIZE(pll_list)))
- pll_desc_id = id[dvb_pll_devcount];
+ nr = ida_simple_get(&pll_ida, 0, DVB_PLL_MAX, GFP_KERNEL);
+ if (nr < 0) {
+ kfree(b1);
+ return NULL;
+ }
+
+ if (id[nr] > DVB_PLL_UNDEFINED && id[nr] < ARRAY_SIZE(pll_list))
+ pll_desc_id = id[nr];

BUG_ON(pll_desc_id < 1 || pll_desc_id >= ARRAY_SIZE(pll_list));

@@ -808,24 +814,20 @@ struct dvb_frontend *dvb_pll_attach(struct dvb_frontend *fe, int pll_addr,
fe->ops.i2c_gate_ctrl(fe, 1);

ret = i2c_transfer (i2c, &msg, 1);
- if (ret != 1) {
- kfree(b1);
- return NULL;
- }
+ if (ret != 1)
+ goto out;
if (fe->ops.i2c_gate_ctrl)
fe->ops.i2c_gate_ctrl(fe, 0);
}

priv = kzalloc(sizeof(struct dvb_pll_priv), GFP_KERNEL);
- if (!priv) {
- kfree(b1);
- return NULL;
- }
+ if (!priv)
+ goto out;

priv->pll_i2c_address = pll_addr;
priv->i2c = i2c;
priv->pll_desc = desc;
- priv->nr = dvb_pll_devcount++;
+ priv->nr = nr;

memcpy(&fe->ops.tuner_ops, &dvb_pll_tuner_ops,
sizeof(struct dvb_tuner_ops));
@@ -858,6 +860,11 @@ struct dvb_frontend *dvb_pll_attach(struct dvb_frontend *fe, int pll_addr,
kfree(b1);

return fe;
+out:
+ kfree(b1);
+ ida_simple_remove(&pll_ida, nr);
+
+ return NULL;
}
EXPORT_SYMBOL(dvb_pll_attach);

@@ -894,9 +901,10 @@ dvb_pll_probe(struct i2c_client *client, const struct i2c_device_id *id)

static int dvb_pll_remove(struct i2c_client *client)
{
- struct dvb_frontend *fe;
+ struct dvb_frontend *fe = i2c_get_clientdata(client);
+ struct dvb_pll_priv *priv = fe->tuner_priv;

- fe = i2c_get_clientdata(client);
+ ida_simple_remove(&pll_ida, priv->nr);
dvb_pll_release(fe);
return 0;
}
--
2.20.1