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Commit	Line	Data
f427ee49 A	1	/*
	2	* Copyright (c) 2020 Apple Inc. All rights reserved.
	3	*
	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
	5	*
	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
	25	*
	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
	27	*/
	28
	29	#include <IOKit/IOLib.h>
	30	#include <kern/debug.h> // for panic()
	31
	32	#include <libkern/ptrauth_utils.h>
	33
	34
	35	#if __has_feature(ptrauth_calls)
	36
	37	/*
	38	* ptrauth_utils_sign_blob_generic
	39	*
	40	* Sign a blob of data with the GA key
	41	*
	42	*/
c3c9b80d	43	__attribute__((noinline))
f427ee49	44	ptrauth_generic_signature_t
c3c9b80d	45	ptrauth_utils_sign_blob_generic(const void * ptr, size_t len_bytes, uint64_t data, int flags)
f427ee49 A	46	{
	47	ptrauth_generic_signature_t sig = 0;
	48
	49	uint64_t rounds = len_bytes / sizeof(uintptr_t);
	50	size_t ntrailing = len_bytes % sizeof(uintptr_t);
	51	uintptr_t trailing = 0;
	52
	53	if (ptr == NULL) {
	54	return 0;
	55	}
	56
	57	/* If address diversification is requested, mix the blob address with the salt */
	58	if (flags & PTRAUTH_ADDR_DIVERSIFY) {
	59	data ^= (uint64_t)ptr;
	60	}
	61
c3c9b80d A	62	/* First round adds ptrauth_utils_sign_blob_generic discrimination. */
	63	sig = ptrauth_sign_generic_data(sig, ptrauth_string_discriminator("ptrauth_utils_sign_blob_generic-prologue") \| 0x01);
	64
	65	/* Second round adds salt */
f427ee49 A	66	sig = ptrauth_sign_generic_data(sig, data);
	67
	68	/* Calculate an additive signature of the buffer */
	69	for (uint64_t i = 0; i < rounds; i++) {
c3c9b80d	70	sig = ptrauth_sign_generic_data((const uintptr_t )ptr, sig);
f427ee49 A	71	ptr += sizeof(uintptr_t);
	72	}
	73
	74	/* ptrauth_sign_generic_data operates on pointer-sized values only,
	75	* so we need to handle trailing bytes for the non-pointer-aligned case */
	76	if (ntrailing) {
c3c9b80d A	77	for (int i = 0; i < ntrailing; i++) {
	78	((uint8_t )&trailing)[i] = ((const uint8_t )ptr)[i];
	79	}
f427ee49 A	80	sig = ptrauth_sign_generic_data(trailing, sig);
	81	}
	82
c3c9b80d A	83
	84	/* Final round to add an additional cookie */
	85	sig = ptrauth_sign_generic_data(sig, ptrauth_string_discriminator("ptrauth_utils_sign_blob_generic-epilogue") \| 0x01);
	86
f427ee49 A	87	return sig;
	88	}
	89
	90	/*
	91	* ptrauth_utils_auth_blob_generic
	92	*
	93	* Authenticate signature produced by ptrauth_utils_sign_blob_generic
	94	*/
c3c9b80d	95	__attribute__((noinline))
f427ee49	96	void
c3c9b80d	97	ptrauth_utils_auth_blob_generic(const void * ptr, size_t len_bytes, uint64_t data, int flags, ptrauth_generic_signature_t signature)
f427ee49 A	98	{
	99	ptrauth_generic_signature_t calculated_signature = 0;
	100
	101	if (ptr == NULL) {
	102	if (flags & PTRAUTH_NON_NULL) {
	103	panic("ptrauth_utils_auth_blob_generic: ptr must not be NULL");
	104	} else {
	105	return;
	106	}
	107	}
	108
	109	if ((calculated_signature = ptrauth_utils_sign_blob_generic(ptr, len_bytes, data, flags)) == signature) {
	110	return;
	111	} else {
	112	panic("signature mismatch for %lu bytes at %p, calculated %lx vs %lx", len_bytes,
	113	ptr,
	114	calculated_signature,
	115	signature);
	116	}
	117	}
	118
	119	#endif //!ptrauth_calls