linux/sound/usb/power.c
Takashi Iwai 57f8770620 ALSA: usb-audio: More validations of descriptor units
Introduce a new helper to validate each audio descriptor unit before
and check the unit before actually accessing it.  This should harden
against the OOB access cases with malformed descriptors that have been
recently frequently reported by fuzzers.

The existing descriptor checks are still kept although they become
superfluous after this patch.  They'll be cleaned up eventually
later.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2019-08-22 10:35:59 +02:00

107 lines
2.5 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* UAC3 Power Domain state management functions
*/
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>
#include <linux/usb/audio-v2.h>
#include <linux/usb/audio-v3.h>
#include "usbaudio.h"
#include "helper.h"
#include "power.h"
struct snd_usb_power_domain *
snd_usb_find_power_domain(struct usb_host_interface *ctrl_iface,
unsigned char id)
{
struct snd_usb_power_domain *pd;
void *p;
pd = kzalloc(sizeof(*pd), GFP_KERNEL);
if (!pd)
return NULL;
p = NULL;
while ((p = snd_usb_find_csint_desc(ctrl_iface->extra,
ctrl_iface->extralen,
p, UAC3_POWER_DOMAIN)) != NULL) {
struct uac3_power_domain_descriptor *pd_desc = p;
int i;
if (!snd_usb_validate_audio_desc(p, UAC_VERSION_3))
continue;
for (i = 0; i < pd_desc->bNrEntities; i++) {
if (pd_desc->baEntityID[i] == id) {
pd->pd_id = pd_desc->bPowerDomainID;
pd->pd_d1d0_rec =
le16_to_cpu(pd_desc->waRecoveryTime1);
pd->pd_d2d0_rec =
le16_to_cpu(pd_desc->waRecoveryTime2);
return pd;
}
}
}
kfree(pd);
return NULL;
}
int snd_usb_power_domain_set(struct snd_usb_audio *chip,
struct snd_usb_power_domain *pd,
unsigned char state)
{
struct usb_device *dev = chip->dev;
unsigned char current_state;
int err, idx;
idx = snd_usb_ctrl_intf(chip) | (pd->pd_id << 8);
err = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
UAC2_CS_CUR,
USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
UAC3_AC_POWER_DOMAIN_CONTROL << 8, idx,
&current_state, sizeof(current_state));
if (err < 0) {
dev_err(&dev->dev, "Can't get UAC3 power state for id %d\n",
pd->pd_id);
return err;
}
if (current_state == state) {
dev_dbg(&dev->dev, "UAC3 power domain id %d already in state %d\n",
pd->pd_id, state);
return 0;
}
err = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0), UAC2_CS_CUR,
USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
UAC3_AC_POWER_DOMAIN_CONTROL << 8, idx,
&state, sizeof(state));
if (err < 0) {
dev_err(&dev->dev, "Can't set UAC3 power state to %d for id %d\n",
state, pd->pd_id);
return err;
}
if (state == UAC3_PD_STATE_D0) {
switch (current_state) {
case UAC3_PD_STATE_D2:
udelay(pd->pd_d2d0_rec * 50);
break;
case UAC3_PD_STATE_D1:
udelay(pd->pd_d1d0_rec * 50);
break;
default:
return -EINVAL;
}
}
dev_dbg(&dev->dev, "UAC3 power domain id %d change to state %d\n",
pd->pd_id, state);
return 0;
}