1 /*
2 * Copyright (c) 2013-2022, Arm Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include <assert.h>
8 #include <errno.h>
9 #include <string.h>
10
11 #include <arch.h>
12 #include <arch_features.h>
13 #include <arch_helpers.h>
14 #include <common/bl_common.h>
15 #include <common/debug.h>
16 #include <drivers/auth/auth_mod.h>
17 #include <drivers/io/io_storage.h>
18 #include <lib/utils.h>
19 #include <lib/xlat_tables/xlat_tables_defs.h>
20 #include <plat/common/platform.h>
21
22 #if TRUSTED_BOARD_BOOT
23 # ifdef DYN_DISABLE_AUTH
24 static int disable_auth;
25
26 /******************************************************************************
27 * API to dynamically disable authentication. Only meant for development
28 * systems. This is only invoked if DYN_DISABLE_AUTH is defined.
29 *****************************************************************************/
dyn_disable_auth(void)30 void dyn_disable_auth(void)
31 {
32 INFO("Disabling authentication of images dynamically\n");
33 disable_auth = 1;
34 }
35 # endif /* DYN_DISABLE_AUTH */
36
37 /******************************************************************************
38 * Function to determine whether the authentication is disabled dynamically.
39 *****************************************************************************/
dyn_is_auth_disabled(void)40 static int dyn_is_auth_disabled(void)
41 {
42 # ifdef DYN_DISABLE_AUTH
43 return disable_auth;
44 # else
45 return 0;
46 # endif
47 }
48 #endif /* TRUSTED_BOARD_BOOT */
49
page_align(uintptr_t value,unsigned dir)50 uintptr_t page_align(uintptr_t value, unsigned dir)
51 {
52 /* Round up the limit to the next page boundary */
53 if ((value & PAGE_SIZE_MASK) != 0U) {
54 value &= ~PAGE_SIZE_MASK;
55 if (dir == UP)
56 value += PAGE_SIZE;
57 }
58
59 return value;
60 }
61
62 /*******************************************************************************
63 * Internal function to load an image at a specific address given
64 * an image ID and extents of free memory.
65 *
66 * If the load is successful then the image information is updated.
67 *
68 * Returns 0 on success, a negative error code otherwise.
69 ******************************************************************************/
load_image(unsigned int image_id,image_info_t * image_data)70 static int load_image(unsigned int image_id, image_info_t *image_data)
71 {
72 uintptr_t dev_handle;
73 uintptr_t image_handle;
74 uintptr_t image_spec;
75 uintptr_t image_base;
76 size_t image_size;
77 size_t bytes_read;
78 int io_result;
79
80 assert(image_data != NULL);
81 assert(image_data->h.version >= VERSION_2);
82
83 image_base = image_data->image_base;
84
85 /* Obtain a reference to the image by querying the platform layer */
86 io_result = plat_get_image_source(image_id, &dev_handle, &image_spec);
87 if (io_result != 0) {
88 WARN("Failed to obtain reference to image id=%u (%i)\n",
89 image_id, io_result);
90 return io_result;
91 }
92
93 /* Attempt to access the image */
94 io_result = io_open(dev_handle, image_spec, &image_handle);
95 if (io_result != 0) {
96 WARN("Failed to access image id=%u (%i)\n",
97 image_id, io_result);
98 return io_result;
99 }
100
101 INFO("Loading image id=%u at address 0x%lx\n", image_id, image_base);
102
103 /* Find the size of the image */
104 io_result = io_size(image_handle, &image_size);
105 if ((io_result != 0) || (image_size == 0U)) {
106 WARN("Failed to determine the size of the image id=%u (%i)\n",
107 image_id, io_result);
108 goto exit;
109 }
110
111 /* Check that the image size to load is within limit */
112 if (image_size > image_data->image_max_size) {
113 WARN("Image id=%u size out of bounds\n", image_id);
114 io_result = -EFBIG;
115 goto exit;
116 }
117
118 /*
119 * image_data->image_max_size is a uint32_t so image_size will always
120 * fit in image_data->image_size.
121 */
122 image_data->image_size = (uint32_t)image_size;
123
124 /* We have enough space so load the image now */
125 /* TODO: Consider whether to try to recover/retry a partially successful read */
126 io_result = io_read(image_handle, image_base, image_size, &bytes_read);
127 if ((io_result != 0) || (bytes_read < image_size)) {
128 WARN("Failed to load image id=%u (%i)\n", image_id, io_result);
129 goto exit;
130 }
131
132 INFO("Image id=%u loaded: 0x%lx - 0x%lx\n", image_id, image_base,
133 (uintptr_t)(image_base + image_size));
134
135 exit:
136 (void)io_close(image_handle);
137 /* Ignore improbable/unrecoverable error in 'close' */
138
139 /* TODO: Consider maintaining open device connection from this bootloader stage */
140 (void)io_dev_close(dev_handle);
141 /* Ignore improbable/unrecoverable error in 'dev_close' */
142
143 return io_result;
144 }
145
146 #if TRUSTED_BOARD_BOOT
147 /*
148 * This function uses recursion to authenticate the parent images up to the root
149 * of trust.
150 */
load_auth_image_recursive(unsigned int image_id,image_info_t * image_data,int is_parent_image)151 static int load_auth_image_recursive(unsigned int image_id,
152 image_info_t *image_data,
153 int is_parent_image)
154 {
155 int rc;
156 unsigned int parent_id;
157
158 /* Use recursion to authenticate parent images */
159 rc = auth_mod_get_parent_id(image_id, &parent_id);
160 if (rc == 0) {
161 rc = load_auth_image_recursive(parent_id, image_data, 1);
162 if (rc != 0) {
163 return rc;
164 }
165 }
166
167 /* Load the image */
168 rc = load_image(image_id, image_data);
169 if (rc != 0) {
170 return rc;
171 }
172
173 /* Authenticate it */
174 rc = auth_mod_verify_img(image_id,
175 (void *)image_data->image_base,
176 image_data->image_size);
177 if (rc != 0) {
178 /* Authentication error, zero memory and flush it right away. */
179 zero_normalmem((void *)image_data->image_base,
180 image_data->image_size);
181 flush_dcache_range(image_data->image_base,
182 image_data->image_size);
183 return -EAUTH;
184 }
185
186 return 0;
187 }
188 #endif /* TRUSTED_BOARD_BOOT */
189
load_auth_image_internal(unsigned int image_id,image_info_t * image_data)190 static int load_auth_image_internal(unsigned int image_id,
191 image_info_t *image_data)
192 {
193 #if TRUSTED_BOARD_BOOT
194 if (dyn_is_auth_disabled() == 0) {
195 return load_auth_image_recursive(image_id, image_data, 0);
196 }
197 #endif
198
199 return load_image(image_id, image_data);
200 }
201
202 /*******************************************************************************
203 * Generic function to load and authenticate an image. The image is actually
204 * loaded by calling the 'load_image()' function. Therefore, it returns the
205 * same error codes if the loading operation failed, or -EAUTH if the
206 * authentication failed. In addition, this function uses recursion to
207 * authenticate the parent images up to the root of trust (if TBB is enabled).
208 ******************************************************************************/
load_auth_image(unsigned int image_id,image_info_t * image_data)209 int load_auth_image(unsigned int image_id, image_info_t *image_data)
210 {
211 int err;
212
213 /*
214 * All firmware banks should be part of the same non-volatile storage as per
215 * PSA FWU specification, hence don't check for any alternate boot source
216 * when PSA FWU is enabled.
217 */
218 #if PSA_FWU_SUPPORT
219 err = load_auth_image_internal(image_id, image_data);
220 #else
221 do {
222 err = load_auth_image_internal(image_id, image_data);
223 } while ((err != 0) && (plat_try_next_boot_source() != 0));
224 #endif /* PSA_FWU_SUPPORT */
225
226 if (err == 0) {
227 /*
228 * If loading of the image gets passed (along with its
229 * authentication in case of Trusted-Boot flow) then measure
230 * it (if MEASURED_BOOT flag is enabled).
231 */
232 err = plat_mboot_measure_image(image_id, image_data);
233 if (err != 0) {
234 return err;
235 }
236
237 /*
238 * Flush the image to main memory so that it can be executed
239 * later by any CPU, regardless of cache and MMU state.
240 */
241 flush_dcache_range(image_data->image_base,
242 image_data->image_size);
243 }
244
245 return err;
246 }
247
248 /*******************************************************************************
249 * Print the content of an entry_point_info_t structure.
250 ******************************************************************************/
print_entry_point_info(const entry_point_info_t * ep_info)251 void print_entry_point_info(const entry_point_info_t *ep_info)
252 {
253 INFO("Entry point address = 0x%lx\n", ep_info->pc);
254 INFO("SPSR = 0x%x\n", ep_info->spsr);
255
256 #define PRINT_IMAGE_ARG(n) \
257 VERBOSE("Argument #" #n " = 0x%llx\n", \
258 (unsigned long long) ep_info->args.arg##n)
259
260 PRINT_IMAGE_ARG(0);
261 PRINT_IMAGE_ARG(1);
262 PRINT_IMAGE_ARG(2);
263 PRINT_IMAGE_ARG(3);
264 #ifdef __aarch64__
265 PRINT_IMAGE_ARG(4);
266 PRINT_IMAGE_ARG(5);
267 PRINT_IMAGE_ARG(6);
268 PRINT_IMAGE_ARG(7);
269 #endif
270 #undef PRINT_IMAGE_ARG
271 }
272
