// SPDX-License-Identifier: GPL-2.0-or-later
//
// Validation of USB-audio class descriptors
//
#include <linux/init.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>
#include <linux/usb/audio-v2.h>
#include <linux/usb/audio-v3.h>
#include <linux/usb/midi.h>
#include "usbaudio.h"
#include "helper.h"
struct usb_desc_validator {
unsigned char protocol;
unsigned char type;
bool (*func)(const void *p, const struct usb_desc_validator *v);
size_t size;
};
#define UAC_VERSION_ALL (unsigned char)(-1)
/* UAC1 only */
static bool validate_uac1_header(const void *p,
const struct usb_desc_validator *v)
{
const struct uac1_ac_header_descriptor *d = p;
return d->bLength >= sizeof(*d) &&
d->bLength >= sizeof(*d) + d->bInCollection;
}
/* for mixer unit; covering all UACs */
static bool validate_mixer_unit(const void *p,
const struct usb_desc_validator *v)
{
const struct uac_mixer_unit_descriptor *d = p;
size_t len;
if (d->bLength < sizeof(*d) || !d->bNrInPins)
return false;
len = sizeof(*d) + d->bNrInPins;
/* We can't determine the bitmap size only from this unit descriptor,
* so just check with the remaining length.
* The actual bitmap is checked at mixer unit parser.
*/
switch (v->protocol) {
case UAC_VERSION_1:
default:
len += 2 + 1; /* wChannelConfig, iChannelNames */
/* bmControls[n*m] */
len += 1; /* iMixer */
break;
case UAC_VERSION_2:
len += 4 + 1; /* bmChannelConfig, iChannelNames */
/* bmMixerControls[n*m] */
len += 1 + 1; /* bmControls, iMixer */
break;
case UAC_VERSION_3:
len += 2; /* wClusterDescrID */
/* bmMixerControls[n*m] */
break;
}
return d->bLength >= len;
}
/* both for processing and extension units; covering all UACs */
static bool validate_processing_unit(const void *p,
const struct usb_desc_validator *v)
{
const struct uac_processing_unit_descriptor *d = p;
const unsigned char *hdr = p;
size_t len, m;
if (d->bLength < sizeof(*d))
return false;
len = sizeof(*d) + d->bNrInPins;
if (d->bLength < len)
return false;
switch (v->protocol) {
case UAC_VERSION_1:
default:
/* bNrChannels, wChannelConfig, iChannelNames */
len += 1 + 2 + 1;
if (d->bLength < len + 1) /* bControlSize */
return false;
m = hdr[len];
len += 1 + m + 1; /* bControlSize, bmControls, iProcessing */
break;
case UAC_VERSION_2:
/* bNrChannels, bmChannelConfig, iChannelNames */
len += 1 + 4 + 1;
if (v->type == UAC2_PROCESSING_UNIT_V2)
len += 2; /* bmControls -- 2 bytes for PU */
else
len += 1; /* bmControls -- 1 byte for EU */
len += 1; /* iProcessing */
break;
case UAC_VERSION_3:
/* wProcessingDescrStr, bmControls */
len += 2 + 4;
break;
}
if (d->bLength < len)
return false;
switch (v->protocol) {
case UAC_VERSION_1:
default:
if (v->type == UAC1_EXTENSION_UNIT)
return true; /* OK */
switch (le16_to_cpu(d->wProcessType)) {
case UAC_PROCESS_UP_DOWNMIX:
case UAC_PROCESS_DOLBY_PROLOGIC:
if (d->bLength < len + 1) /* bNrModes */
return false;
m = hdr[len];
len += 1 + m * 2; /* bNrModes, waModes(n) */
break;
default:
break;
}
break;
case UAC_VERSION_2:
if (v->type == UAC2_EXTENSION_UNIT_V2)
return true; /* OK */
switch (le16_to_cpu(d->wProcessType)) {
case UAC2_PROCESS_UP_DOWNMIX:
case UAC2_PROCESS_DOLBY_PROLOCIC: /* SiC! */
if (d->bLength < len + 1) /* bNrModes */
return false;
m = hdr[len];
len += 1 + m * 4; /* bNrModes, daModes(n) */
break;
default:
break;
}
break;
case UAC_VERSION_3:
if (v->type == UAC3_EXTENSION_UNIT) {
len += 2; /* wClusterDescrID */
break;
}
switch (le16_to_cpu(d->wProcessType)) {
case UAC3_PROCESS_UP_DOWNMIX:
if (d->bLength < len + 1) /* bNrModes */
return false;
m = hdr[len];
len += 1 + m * 2; /* bNrModes, waClusterDescrID(n) */
break;
case UAC3_PROCESS_MULTI_FUNCTION:
len += 2 + 4; /* wClusterDescrID, bmAlgorighms */
break;
default:
break;
}
break;
}
if (d->bLength < len)
return false;
return true;
}
/* both for selector and clock selector units; covering all UACs */
static bool validate_selector_unit(const void *p,
const struct usb_desc_validator *v)
{
const struct uac_selector_unit_descriptor *d = p;
size_t len;
if (d->bLength < sizeof(*d))
return false;
len = sizeof(*d) + d->bNrInPins;
switch (v->protocol) {
case UAC_VERSION_1:
default:
len += 1; /* iSelector */
break;
case UAC_VERSION_2:
len += 1 + 1; /* bmControls, iSelector */
break;
case UAC_VERSION_3:
len += 4 + 2; /* bmControls, wSelectorDescrStr */
break;
}
return d->bLength >= len;
}
static bool validate_uac1_feature_unit(const void *p,
const struct usb_desc_validator *v)
{
const struct uac_feature_unit_descriptor *d = p;
if (d->bLength < sizeof(*d) || !d->bControlSize)
return false;
/* at least bmaControls(0) for master channel + iFeature */
return d->bLength >= sizeof(*d) + d->bControlSize + 1;
}
static bool validate_uac2_feature_unit(const void *p,
const struct usb_desc_validator *v)
{
const struct uac2_feature_unit_descriptor *d = p;
if (d->bLength < sizeof(*d))
return false;
/* at least bmaControls(0) for master channel + iFeature */
return d->bLength >= sizeof(*d) + 4 + 1;
}
static bool validate_uac3_feature_unit(const void *p,
const struct usb_desc_validator *v)
{
const struct uac3_feature_unit_descriptor *d = p;
if (d->bLength < sizeof(*d))
return false;
/* at least bmaControls(0) for master channel + wFeatureDescrStr */
return d->bLength >= sizeof(*d) + 4 + 2;
}
static bool validate_midi_out_jack(const void *p,
const struct usb_desc_validator *v)
{
const struct usb_midi_out_jack_descriptor *d = p;
return d->bLength >= sizeof(*d) &&
d->bLength >= sizeof(*d) + d->bNrInputPins * 2;
}
#define FIXED(p, t, s) { .protocol = (p), .type = (t), .size = sizeof(s) }
#define FUNC(p, t, f) { .protocol = (p), .type = (t), .func = (f) }
static const struct usb_desc_validator audio_validators[] = {
/* UAC1 */
FUNC(UAC_VERSION_1, UAC_HEADER, validate_uac1_header),
FIXED(UAC_VERSION_1, UAC_INPUT_TERMINAL,
struct uac_input_terminal_descriptor),
FIXED(UAC_VERSION_1, UAC_OUTPUT_TERMINAL,
struct uac1_output_terminal_descriptor),
FUNC(UAC_VERSION_1, UAC_MIXER_UNIT, validate_mixer_unit),
FUNC(UAC_VERSION_1, UAC_SELECTOR_UNIT, validate_selector_unit),
FUNC(UAC_VERSION_1, UAC_FEATURE_UNIT, validate_uac1_feature_unit),
FUNC(UAC_VERSION_1, UAC1_PROCESSING_UNIT, validate_processing_unit),
FUNC(UAC_VERSION_1, UAC1_EXTENSION_UNIT, validate_processing_unit),
/* UAC2 */
FIXED(UAC_VERSION_2, UAC_HEADER, struct uac2_ac_header_descriptor),
FIXED(UAC_VERSION_2, UAC_INPUT_TERMINAL,
struct uac2_input_terminal_descriptor),
FIXED(UAC_VERSION_2, UAC_OUTPUT_TERMINAL,
struct uac2_output_terminal_descriptor),
FUNC(UAC_VERSION_2, UAC_MIXER_UNIT, validate_mixer_unit),
FUNC(UAC_VERSION_2, UAC_SELECTOR_UNIT, validate_selector_unit),
FUNC(UAC_VERSION_2, UAC_FEATURE_UNIT, validate_uac2_feature_unit),
/* UAC_VERSION_2, UAC2_EFFECT_UNIT: not implemented yet */
FUNC(UAC_VERSION_2, UAC2_PROCESSING_UNIT_V2, validate_processing_unit),
FUNC(UAC_VERSION_2, UAC2_EXTENSION_UNIT_V2, validate_processing_unit),
FIXED(UAC_VERSION_2, UAC2_CLOCK_SOURCE,
struct uac_clock_source_descriptor),
FUNC(UAC_VERSION_2, UAC2_CLOCK_SELECTOR, validate_selector_unit),
FIXED(UAC_VERSION_2, UAC2_CLOCK_MULTIPLIER,
struct uac_clock_multiplier_descriptor),
/* UAC_VERSION_2, UAC2_SAMPLE_RATE_CONVERTER: not implemented yet */
/* UAC3 */
FIXED(UAC_VERSION_2, UAC_HEADER, struct uac3_ac_header_descriptor),
FIXED(UAC_VERSION_3, UAC_INPUT_TERMINAL,
struct uac3_input_terminal_descriptor),
FIXED(UAC_VERSION_3, UAC_OUTPUT_TERMINAL,
struct uac3_output_terminal_descriptor),
/* UAC_VERSION_3, UAC3_EXTENDED_TERMINAL: not implemented yet */
FUNC(UAC_VERSION_3, UAC3_MIXER_UNIT, validate_mixer_unit),
FUNC(UAC_VERSION_3, UAC3_SELECTOR_UNIT, validate_selector_unit),
FUNC(UAC_VERSION_3, UAC_FEATURE_UNIT, validate_uac3_feature_unit),
/* UAC_VERSION_3, UAC3_EFFECT_UNIT: not implemented yet */
FUNC(UAC_VERSION_3, UAC3_PROCESSING_UNIT, validate_processing_unit),
FUNC(UAC_VERSION_3, UAC3_EXTENSION_UNIT, validate_processing_unit),
FIXED(UAC_VERSION_3, UAC3_CLOCK_SOURCE,
struct uac3_clock_source_descriptor),
FUNC(UAC_VERSION_3, UAC3_CLOCK_SELECTOR, validate_selector_unit),
FIXED(UAC_VERSION_3, UAC3_CLOCK_MULTIPLIER,
struct uac3_clock_multiplier_descriptor),
/* UAC_VERSION_3, UAC3_SAMPLE_RATE_CONVERTER: not implemented yet */
/* UAC_VERSION_3, UAC3_CONNECTORS: not implemented yet */
{ } /* terminator */
};
static const struct usb_desc_validator midi_validators[] = {
FIXED(UAC_VERSION_ALL, USB_MS_HEADER,
struct usb_ms_header_descriptor),
FIXED(UAC_VERSION_ALL, USB_MS_MIDI_IN_JACK,
struct usb_midi_in_jack_descriptor),
FUNC(UAC_VERSION_ALL, USB_MS_MIDI_OUT_JACK,
validate_midi_out_jack),
{ } /* terminator */
};
/* Validate the given unit descriptor, return true if it's OK */
static bool validate_desc(unsigned char *hdr, int protocol,
const struct usb_desc_validator *v)
{
if (hdr[1] != USB_DT_CS_INTERFACE)
return true; /* don't care */
for (; v->type; v++) {
if (v->type == hdr[2] &&
(v->protocol == UAC_VERSION_ALL ||
v->protocol == protocol)) {
if (v->func)
return v->func(hdr, v);
/* check for the fixed size */
return hdr[0] >= v->size;
}
}
return true; /* not matching, skip validation */
}
bool snd_usb_validate_audio_desc(void *p, int protocol)
{
unsigned char *c = p;
bool valid;
valid = validate_desc(p, protocol, audio_validators);
if (!valid && snd_usb_skip_validation) {
print_hex_dump(KERN_ERR, "USB-audio: buggy audio desc: ",
DUMP_PREFIX_NONE, 16, 1, c, c[0], true);
valid = true;
}
return valid;
}
bool snd_usb_validate_midi_desc(void *p)
{
unsigned char *c = p;
bool valid;
valid = validate_desc(p, UAC_VERSION_1, midi_validators);
if (!valid && snd_usb_skip_validation) {
print_hex_dump(KERN_ERR, "USB-audio: buggy midi desc: ",
DUMP_PREFIX_NONE, 16, 1, c, c[0], true);
valid = true;
}
return valid;
}
Codebase Browser
linux