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// 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_uac3_power_domain_unit(const void *p,					    const struct usb_desc_validator *v){	const struct uac3_power_domain_descriptor *d = p; 	if (d->bLength < sizeof(*d))		return false;	/* baEntities[] + wPDomainDescrStr */	return d->bLength >= sizeof(*d) + d->bNrEntities + 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),	/* just a stop-gap, it should be a proper function for the array	 * once if the unit is really parsed/used	 */	FIXED(UAC_VERSION_2, UAC2_EFFECT_UNIT,	      struct uac2_effect_unit_descriptor),	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_3, 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, UAC3_FEATURE_UNIT, validate_uac3_feature_unit),	FIXED(UAC_VERSION_3, UAC3_EFFECT_UNIT,	      struct uac2_effect_unit_descriptor), /* sharing the same struct */	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 */	FUNC(UAC_VERSION_3, UAC3_POWER_DOMAIN, validate_uac3_power_domain_unit),	{ } /* 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;}

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