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features/FEATURE_UVISOR/source/rtx/secure_allocator.c@1:2b6e8130a0ac, 2018-02-22 (annotated)

Committer:
calmantara186
Date:
Thu Feb 22 14:05:19 2018 +0000
Revision:
1:2b6e8130a0ac
Parent:
0:f269e3021894 
mbed os

Who changed what in which revision?

UserRevisionLine numberNew contents of line
elessair 0:f269e3021894 1 /*
elessair 0:f269e3021894 2 * Copyright (c) 2016, ARM Limited, All Rights Reserved
elessair 0:f269e3021894 3 * SPDX-License-Identifier: Apache-2.0
elessair 0:f269e3021894 4 *
elessair 0:f269e3021894 5 * Licensed under the Apache License, Version 2.0 (the "License"); you may
elessair 0:f269e3021894 6 * not use this file except in compliance with the License.
elessair 0:f269e3021894 7 * You may obtain a copy of the License at
elessair 0:f269e3021894 8 *
elessair 0:f269e3021894 9 * http://www.apache.org/licenses/LICENSE-2.0
elessair 0:f269e3021894 10 *
elessair 0:f269e3021894 11 * Unless required by applicable law or agreed to in writing, software
elessair 0:f269e3021894 12 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
elessair 0:f269e3021894 13 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
elessair 0:f269e3021894 14 * See the License for the specific language governing permissions and
elessair 0:f269e3021894 15 * limitations under the License.
elessair 0:f269e3021894 16 */
elessair 0:f269e3021894 17
elessair 0:f269e3021894 18 #include "rt_TypeDef.h"
elessair 0:f269e3021894 19 #include "rt_Memory.h"
elessair 0:f269e3021894 20
elessair 0:f269e3021894 21 #include "secure_allocator.h"
elessair 0:f269e3021894 22 #include "uvisor-lib/uvisor-lib.h"
elessair 0:f269e3021894 23
elessair 0:f269e3021894 24 #include <stdio.h>
elessair 0:f269e3021894 25 #include <stdlib.h>
elessair 0:f269e3021894 26 #include <string.h>
elessair 0:f269e3021894 27
elessair 0:f269e3021894 28 /* Use printf with caution inside malloc: printf may allocate memory itself,
elessair 0:f269e3021894 29 so using printf in malloc may lead to recursive calls! */
elessair 0:f269e3021894 30 #define DPRINTF(...) {}
elessair 0:f269e3021894 31
elessair 0:f269e3021894 32 /* offsetof is a gcc built-in function, this is the manual implementation */
elessair 0:f269e3021894 33 #define OFFSETOF(type, member) ((uint32_t) (&(((type *)(0))->member)))
elessair 0:f269e3021894 34
elessair 0:f269e3021894 35 /* Internal structure currently only contains the page table. */
elessair 0:f269e3021894 36 typedef struct {
elessair 0:f269e3021894 37 UvisorPageTable table;
elessair 0:f269e3021894 38 } SecureAllocatorInternal;
elessair 0:f269e3021894 39
elessair 0:f269e3021894 40 static inline UvisorPageTable * table(SecureAllocator allocator) {
elessair 0:f269e3021894 41 return &(((SecureAllocatorInternal *) allocator)->table);
elessair 0:f269e3021894 42 }
elessair 0:f269e3021894 43
elessair 0:f269e3021894 44 SecureAllocator secure_allocator_create_with_pool(
elessair 0:f269e3021894 45 void * mem,
elessair 0:f269e3021894 46 size_t bytes)
elessair 0:f269e3021894 47 {
elessair 0:f269e3021894 48 SecureAllocatorInternal * allocator = mem;
elessair 0:f269e3021894 49 /* Signal that this is non-page allocated memory. */
elessair 0:f269e3021894 50 allocator->table.page_size = bytes;
elessair 0:f269e3021894 51 allocator->table.page_count = 0;
elessair 0:f269e3021894 52 /* The internal rt_Memory MEMP structure must be placed AFTER table.page_origins[0] !!! */
elessair 0:f269e3021894 53 size_t offset = OFFSETOF(SecureAllocatorInternal, table.page_origins) + sizeof(((UvisorPageTable) {0}).page_origins);
elessair 0:f269e3021894 54 /* Create MEMP structure inside the memory. */
elessair 0:f269e3021894 55 if (rt_init_mem(mem + offset, bytes - offset)) {
elessair 0:f269e3021894 56 /* Abort if failed. */
elessair 0:f269e3021894 57 DPRINTF("secure_allocator_create_with_pool: MEMP allocator creation failed\n\n");
elessair 0:f269e3021894 58 return NULL;
elessair 0:f269e3021894 59 }
elessair 0:f269e3021894 60 /* Remember the MEMP pointer though. */
elessair 0:f269e3021894 61 allocator->table.page_origins[0] = mem + offset;
elessair 0:f269e3021894 62 DPRINTF("secure_allocator_create_with_pool: Created MEMP allocator %p with offset %d\n\n", mem + offset, offset);
elessair 0:f269e3021894 63 return allocator;
elessair 0:f269e3021894 64 }
elessair 0:f269e3021894 65
elessair 0:f269e3021894 66 SecureAllocator secure_allocator_create_with_pages(
elessair 0:f269e3021894 67 size_t size,
elessair 0:f269e3021894 68 size_t maximum_malloc_size)
elessair 0:f269e3021894 69 {
elessair 0:f269e3021894 70 const uint32_t page_size = uvisor_get_page_size();
elessair 0:f269e3021894 71 /* The rt_Memory allocator puts one MEMP structure at both the
elessair 0:f269e3021894 72 * beginning and end of the memory pool. */
elessair 0:f269e3021894 73 const size_t block_overhead = 2 * sizeof(MEMP);
elessair 0:f269e3021894 74 const size_t page_size_with_overhead = page_size + block_overhead;
elessair 0:f269e3021894 75 /* Calculate the integer part of required the page count. */
elessair 0:f269e3021894 76 size_t page_count = size / page_size_with_overhead;
elessair 0:f269e3021894 77 /* Add another page if the remainder is not zero. */
elessair 0:f269e3021894 78 if (size - page_count * page_size_with_overhead) {
elessair 0:f269e3021894 79 page_count++;
elessair 0:f269e3021894 80 }
elessair 0:f269e3021894 81 DPRINTF("secure_allocator_create_with_pages: Requesting %u pages for at least %uB\n", page_count, size);
elessair 0:f269e3021894 82
elessair 0:f269e3021894 83 /* Compute the maximum allocation within our blocks. */
elessair 0:f269e3021894 84 size_t maximum_allocation_size = page_size - block_overhead;
elessair 0:f269e3021894 85 /* If the required maximum allocation is larger than we can provide, abort. */
elessair 0:f269e3021894 86 if (maximum_malloc_size > maximum_allocation_size) {
elessair 0:f269e3021894 87 DPRINTF("secure_allocator_create_with_pages: Maximum allocation request %uB is larger then available %uB\n\n", maximum_malloc_size, maximum_allocation_size);
elessair 0:f269e3021894 88 return NULL;
elessair 0:f269e3021894 89 }
elessair 0:f269e3021894 90
elessair 0:f269e3021894 91 /* Compute the required memory size for the page table. */
elessair 0:f269e3021894 92 size_t allocator_type_size = sizeof(SecureAllocatorInternal);
elessair 0:f269e3021894 93 /* Add size for each additional page. */
elessair 0:f269e3021894 94 allocator_type_size += (page_count - 1) * sizeof(((UvisorPageTable) {0}).page_origins);
elessair 0:f269e3021894 95 /* Allocate this much memory. */
elessair 0:f269e3021894 96 SecureAllocatorInternal * const allocator = malloc(allocator_type_size);
elessair 0:f269e3021894 97 /* If malloc failed, abort. */
elessair 0:f269e3021894 98 if (allocator == NULL) {
elessair 0:f269e3021894 99 DPRINTF("secure_allocator_create_with_pages: SecureAllocatorInternal failed to be allocated!\n\n");
elessair 0:f269e3021894 100 return NULL;
elessair 0:f269e3021894 101 }
elessair 0:f269e3021894 102
elessair 0:f269e3021894 103 /* Prepare the page table. */
elessair 0:f269e3021894 104 allocator->table.page_size = page_size;
elessair 0:f269e3021894 105 allocator->table.page_count = page_count;
elessair 0:f269e3021894 106 /* Get me some pages. */
elessair 0:f269e3021894 107 if (uvisor_page_malloc((UvisorPageTable *) &(allocator->table))) {
elessair 0:f269e3021894 108 free(allocator);
elessair 0:f269e3021894 109 DPRINTF("secure_allocator_create_with_pages: Not enough free pages available!\n\n");
elessair 0:f269e3021894 110 return NULL;
elessair 0:f269e3021894 111 }
elessair 0:f269e3021894 112
elessair 0:f269e3021894 113 /* Initialize a MEMP structure in all pages. */
elessair 0:f269e3021894 114 for(size_t ii = 0; ii < page_count; ii++) {
elessair 0:f269e3021894 115 /* Add each page as a pool. */
elessair 0:f269e3021894 116 rt_init_mem(allocator->table.page_origins[ii], page_size);
elessair 0:f269e3021894 117 DPRINTF("secure_allocator_create_with_pages: Created MEMP allocator %p with offset %d\n", allocator->table.page_origins[ii], 0);
elessair 0:f269e3021894 118 }
elessair 0:f269e3021894 119 DPRINTF("\n");
elessair 0:f269e3021894 120 /* Aaaand across the line. */
elessair 0:f269e3021894 121 return (SecureAllocator) allocator;
elessair 0:f269e3021894 122 }
elessair 0:f269e3021894 123
elessair 0:f269e3021894 124 int secure_allocator_destroy(
elessair 0:f269e3021894 125 SecureAllocator allocator)
elessair 0:f269e3021894 126 {
elessair 0:f269e3021894 127 DPRINTF("secure_allocator_destroy: Destroying MEMP allocator at %p\n", table(allocator)->page_origins[0]);
elessair 0:f269e3021894 128
elessair 0:f269e3021894 129 /* Check if we are working on statically allocated memory. */
elessair 0:f269e3021894 130 SecureAllocatorInternal * alloc = (SecureAllocatorInternal * const) allocator;
elessair 0:f269e3021894 131 if (alloc->table.page_count == 0) {
elessair 0:f269e3021894 132 DPRINTF("secure_allocator_destroy: %p is not page-backed memory, not freeing!\n", allocator);
elessair 0:f269e3021894 133 return -1;
elessair 0:f269e3021894 134 }
elessair 0:f269e3021894 135
elessair 0:f269e3021894 136 /* Free all pages. */
elessair 0:f269e3021894 137 if (uvisor_page_free(&(alloc->table))) {
elessair 0:f269e3021894 138 DPRINTF("secure_allocator_destroy: Unable to free pages!\n\n");
elessair 0:f269e3021894 139 return -1;
elessair 0:f269e3021894 140 }
elessair 0:f269e3021894 141
elessair 0:f269e3021894 142 /* Free the allocator structure. */
elessair 0:f269e3021894 143 free(allocator);
elessair 0:f269e3021894 144
elessair 0:f269e3021894 145 DPRINTF("\n");
elessair 0:f269e3021894 146 return 0;
elessair 0:f269e3021894 147 }
elessair 0:f269e3021894 148
elessair 0:f269e3021894 149 void * secure_malloc(
elessair 0:f269e3021894 150 SecureAllocator allocator,
elessair 0:f269e3021894 151 size_t size)
elessair 0:f269e3021894 152 {
elessair 0:f269e3021894 153 size_t index = 0;
elessair 0:f269e3021894 154 do {
elessair 0:f269e3021894 155 /* Search in this page. */
elessair 0:f269e3021894 156 void * mem = rt_alloc_mem(table(allocator)->page_origins[index], size);
elessair 0:f269e3021894 157 /* Return if we found something. */
elessair 0:f269e3021894 158 if (mem) {
elessair 0:f269e3021894 159 DPRINTF("secure_malloc: Found %4uB in page %u at %p\n", size, index, mem);
elessair 0:f269e3021894 160 return mem;
elessair 0:f269e3021894 161 }
elessair 0:f269e3021894 162 /* Otherwise, go to the next page. */
elessair 0:f269e3021894 163 index++;
elessair 0:f269e3021894 164 } /* Continue search if more pages are available. */
elessair 0:f269e3021894 165 while (index < table(allocator)->page_count);
elessair 0:f269e3021894 166
elessair 0:f269e3021894 167 DPRINTF("secure_malloc: Out of memory in allocator %p \n", allocator);
elessair 0:f269e3021894 168 /* We found nothing. */
elessair 0:f269e3021894 169 return NULL;
elessair 0:f269e3021894 170 }
elessair 0:f269e3021894 171
elessair 0:f269e3021894 172 void * secure_realloc(
elessair 0:f269e3021894 173 SecureAllocator allocator,
elessair 0:f269e3021894 174 void * ptr,
elessair 0:f269e3021894 175 size_t new_size)
elessair 0:f269e3021894 176 {
elessair 0:f269e3021894 177 /* TODO: THIS IS A NAIVE IMPLEMENTATION, which always allocates new
elessair 0:f269e3021894 178 memory, and copies the memory, then frees the old memory. */
elessair 0:f269e3021894 179
elessair 0:f269e3021894 180 /* Allocate new memory. */
elessair 0:f269e3021894 181 void * new_ptr = secure_malloc(allocator, new_size);
elessair 0:f269e3021894 182 /* If memory allocation failed, abort. */
elessair 0:f269e3021894 183 if (new_ptr == NULL) {
elessair 0:f269e3021894 184 return NULL;
elessair 0:f269e3021894 185 }
elessair 0:f269e3021894 186
elessair 0:f269e3021894 187 /* Passing NULL as ptr is legal, realloc acts as malloc then. */
elessair 0:f269e3021894 188 if (ptr) {
elessair 0:f269e3021894 189 /* Get the size of the ptr memory. */
elessair 0:f269e3021894 190 size_t size = ((MEMP *) ((uint32_t) ptr - sizeof(MEMP)))->len;
elessair 0:f269e3021894 191 /* Copy the memory to the new location, min(new_size, size). */
elessair 0:f269e3021894 192 memcpy(new_ptr, ptr, new_size < size ? new_size : size);
elessair 0:f269e3021894 193 /* Free the previous memory. */
elessair 0:f269e3021894 194 secure_free(allocator, ptr);
elessair 0:f269e3021894 195 }
elessair 0:f269e3021894 196 return new_ptr;
elessair 0:f269e3021894 197 }
elessair 0:f269e3021894 198
elessair 0:f269e3021894 199 void secure_free(
elessair 0:f269e3021894 200 SecureAllocator allocator,
elessair 0:f269e3021894 201 void * ptr)
elessair 0:f269e3021894 202 {
elessair 0:f269e3021894 203 size_t index = 0;
elessair 0:f269e3021894 204 do {
elessair 0:f269e3021894 205 /* Search in this page. */
elessair 0:f269e3021894 206 int ret = rt_free_mem(table(allocator)->page_origins[index], ptr);
elessair 0:f269e3021894 207 /* Return if free was successful. */
elessair 0:f269e3021894 208 if (ret == 0) {
elessair 0:f269e3021894 209 DPRINTF("secure_free: Freed %p in page %u.\n", ptr, index);
elessair 0:f269e3021894 210 return;
elessair 0:f269e3021894 211 }
elessair 0:f269e3021894 212 /* Otherwise, go to the next page. */
elessair 0:f269e3021894 213 index++;
elessair 0:f269e3021894 214 } /* Continue search if more pages are available. */
elessair 0:f269e3021894 215 while (index < table(allocator)->page_count);
elessair 0:f269e3021894 216
elessair 0:f269e3021894 217 DPRINTF("secure_free: %p not found in allocator %p!\n", ptr, allocator);
elessair 0:f269e3021894 218 /* We found nothing. */
elessair 0:f269e3021894 219 return;
elessair 0:f269e3021894 220 }