1 // SPDX-License-Identifier: BSD-2-Clause 2 /* 3 * Copyright (c) 2014, STMicroelectronics International N.V. 4 * Copyright (c) 2015-2020, 2022 Linaro Limited 5 */ 6 7 #include <initcall.h> 8 #include <kernel/linker.h> 9 #include <kernel/user_access.h> 10 #include <kernel/user_mode_ctx.h> 11 #include <memtag.h> 12 #include <mm/vm.h> 13 #include <string.h> 14 #include <tee_api_types.h> 15 #include <types_ext.h> 16 17 #define BB_ALIGNMENT (sizeof(long) * 2) 18 19 static struct user_mode_ctx *get_current_uctx(void) 20 { 21 struct ts_session *s = ts_get_current_session(); 22 23 if (!is_user_mode_ctx(s->ctx)) { 24 /* 25 * We may be called within a PTA session, which doesn't 26 * have a user_mode_ctx. Here, try to retrieve the 27 * user_mode_ctx associated with the calling session. 28 */ 29 s = TAILQ_NEXT(s, link_tsd); 30 if (!s || !is_user_mode_ctx(s->ctx)) 31 return NULL; 32 } 33 34 return to_user_mode_ctx(s->ctx); 35 } 36 37 TEE_Result check_user_access(uint32_t flags, const void *uaddr, size_t len) 38 { 39 struct user_mode_ctx *uctx = get_current_uctx(); 40 41 if (!uctx) 42 return TEE_ERROR_GENERIC; 43 44 return vm_check_access_rights(uctx, flags, (vaddr_t)uaddr, len); 45 } 46 47 TEE_Result copy_from_user(void *kaddr, const void *uaddr, size_t len) 48 { 49 uint32_t flags = TEE_MEMORY_ACCESS_READ | TEE_MEMORY_ACCESS_ANY_OWNER; 50 TEE_Result res = TEE_SUCCESS; 51 52 uaddr = memtag_strip_tag_const(uaddr); 53 res = check_user_access(flags, uaddr, len); 54 if (!res) { 55 enter_user_access(); 56 memcpy(kaddr, uaddr, len); 57 exit_user_access(); 58 } 59 60 return res; 61 } 62 63 TEE_Result copy_to_user(void *uaddr, const void *kaddr, size_t len) 64 { 65 uint32_t flags = TEE_MEMORY_ACCESS_WRITE | TEE_MEMORY_ACCESS_ANY_OWNER; 66 TEE_Result res = TEE_SUCCESS; 67 68 uaddr = memtag_strip_tag(uaddr); 69 res = check_user_access(flags, uaddr, len); 70 if (!res) { 71 enter_user_access(); 72 memcpy(uaddr, kaddr, len); 73 exit_user_access(); 74 } 75 76 return res; 77 } 78 79 TEE_Result copy_from_user_private(void *kaddr, const void *uaddr, size_t len) 80 { 81 uint32_t flags = TEE_MEMORY_ACCESS_READ; 82 TEE_Result res = TEE_SUCCESS; 83 84 uaddr = memtag_strip_tag_const(uaddr); 85 res = check_user_access(flags, uaddr, len); 86 if (!res) { 87 enter_user_access(); 88 memcpy(kaddr, uaddr, len); 89 exit_user_access(); 90 } 91 92 return res; 93 } 94 95 TEE_Result copy_to_user_private(void *uaddr, const void *kaddr, size_t len) 96 { 97 uint32_t flags = TEE_MEMORY_ACCESS_WRITE; 98 TEE_Result res = TEE_SUCCESS; 99 100 uaddr = memtag_strip_tag(uaddr); 101 res = check_user_access(flags, uaddr, len); 102 if (!res) { 103 enter_user_access(); 104 memcpy(uaddr, kaddr, len); 105 exit_user_access(); 106 } 107 108 return res; 109 } 110 111 static void *maybe_tag_bb(void *buf, size_t sz) 112 { 113 static_assert(MEMTAG_GRANULE_SIZE <= BB_ALIGNMENT); 114 115 if (!MEMTAG_IS_ENABLED) 116 return buf; 117 118 assert(!((vaddr_t)buf % MEMTAG_GRANULE_SIZE)); 119 return memtag_set_random_tags(buf, ROUNDUP(sz, MEMTAG_GRANULE_SIZE)); 120 } 121 122 static void maybe_untag_bb(void *buf, size_t sz) 123 { 124 if (MEMTAG_IS_ENABLED) { 125 assert(!((vaddr_t)buf % MEMTAG_GRANULE_SIZE)); 126 memtag_set_tags(buf, ROUNDUP(sz, MEMTAG_GRANULE_SIZE), 0); 127 } 128 } 129 130 void *bb_alloc(size_t len) 131 { 132 struct user_mode_ctx *uctx = get_current_uctx(); 133 size_t offs = 0; 134 void *bb = NULL; 135 136 if (uctx && !ADD_OVERFLOW(uctx->bbuf_offs, len, &offs) && 137 offs <= uctx->bbuf_size) { 138 bb = maybe_tag_bb(uctx->bbuf + uctx->bbuf_offs, len); 139 uctx->bbuf_offs = ROUNDUP(offs, BB_ALIGNMENT); 140 } 141 return bb; 142 } 143 144 static void bb_free_helper(struct user_mode_ctx *uctx, vaddr_t bb, size_t len) 145 { 146 vaddr_t bbuf = (vaddr_t)uctx->bbuf; 147 148 if (bb >= bbuf && IS_ALIGNED(bb, BB_ALIGNMENT)) { 149 size_t prev_offs = bb - bbuf; 150 151 /* 152 * Even if we can't update offset we can still invalidate 153 * the memory allocation. 154 */ 155 maybe_untag_bb((void *)bb, len); 156 157 if (prev_offs + ROUNDUP(len, BB_ALIGNMENT) == uctx->bbuf_offs) 158 uctx->bbuf_offs = prev_offs; 159 } 160 } 161 162 void bb_free(void *bb, size_t len) 163 { 164 struct user_mode_ctx *uctx = get_current_uctx(); 165 166 if (uctx) 167 bb_free_helper(uctx, memtag_strip_tag_vaddr(bb), len); 168 } 169 170 void bb_reset(void) 171 { 172 struct user_mode_ctx *uctx = get_current_uctx(); 173 174 if (uctx) { 175 /* 176 * Only the part up to the offset have been allocated, so 177 * no need to clear tags beyond that. 178 */ 179 maybe_untag_bb(uctx->bbuf, uctx->bbuf_offs); 180 181 uctx->bbuf_offs = 0; 182 } 183 } 184 185 TEE_Result clear_user(void *uaddr, size_t n) 186 { 187 uint32_t flags = TEE_MEMORY_ACCESS_WRITE | TEE_MEMORY_ACCESS_ANY_OWNER; 188 TEE_Result res = TEE_SUCCESS; 189 190 uaddr = memtag_strip_tag(uaddr); 191 res = check_user_access(flags, uaddr, n); 192 if (res) 193 return res; 194 195 enter_user_access(); 196 memset(uaddr, 0, n); 197 exit_user_access(); 198 199 return TEE_SUCCESS; 200 } 201 202 size_t strnlen_user(const void *uaddr, size_t len) 203 { 204 uint32_t flags = TEE_MEMORY_ACCESS_READ | TEE_MEMORY_ACCESS_ANY_OWNER; 205 TEE_Result res = TEE_SUCCESS; 206 size_t n = 0; 207 208 uaddr = memtag_strip_tag_const(uaddr); 209 res = check_user_access(flags, uaddr, len); 210 if (!res) { 211 enter_user_access(); 212 n = strnlen(uaddr, len); 213 exit_user_access(); 214 } 215 216 return n; 217 } 218 219 TEE_Result bb_memdup_user(const void *src, size_t len, void **p) 220 { 221 TEE_Result res = TEE_SUCCESS; 222 void *buf = NULL; 223 224 buf = bb_alloc(len); 225 if (!buf) 226 return TEE_ERROR_OUT_OF_MEMORY; 227 228 res = copy_from_user(buf, src, len); 229 if (res) 230 bb_free(buf, len); 231 else 232 *p = buf; 233 234 return res; 235 } 236 237 TEE_Result bb_memdup_user_private(const void *src, size_t len, void **p) 238 { 239 TEE_Result res = TEE_SUCCESS; 240 void *buf = NULL; 241 242 buf = bb_alloc(len); 243 if (!buf) 244 return TEE_ERROR_OUT_OF_MEMORY; 245 246 res = copy_from_user_private(buf, src, len); 247 if (res) 248 bb_free(buf, len); 249 else 250 *p = buf; 251 252 return res; 253 } 254 255 TEE_Result bb_strndup_user(const char *src, size_t maxlen, char **dst, 256 size_t *dstlen) 257 { 258 uint32_t flags = TEE_MEMORY_ACCESS_READ | TEE_MEMORY_ACCESS_ANY_OWNER; 259 TEE_Result res = TEE_SUCCESS; 260 size_t l = 0; 261 char *d = NULL; 262 263 src = memtag_strip_tag_const(src); 264 res = check_user_access(flags, src, maxlen); 265 if (res) 266 return res; 267 268 enter_user_access(); 269 l = strnlen(src, maxlen); 270 exit_user_access(); 271 272 d = bb_alloc(l + 1); 273 if (!d) 274 return TEE_ERROR_OUT_OF_MEMORY; 275 276 enter_user_access(); 277 memcpy(d, src, l); 278 exit_user_access(); 279 280 d[l] = 0; 281 282 *dst = d; 283 *dstlen = l; 284 return TEE_SUCCESS; 285 } 286 287 TEE_Result copy_kaddr_to_uref(uint32_t *uref, void *kaddr) 288 { 289 uint32_t ref = kaddr_to_uref(kaddr); 290 291 return copy_to_user_private(uref, &ref, sizeof(ref)); 292 } 293 294 uint32_t kaddr_to_uref(void *kaddr) 295 { 296 if (MEMTAG_IS_ENABLED) { 297 unsigned int uref_tag_shift = 32 - MEMTAG_TAG_WIDTH; 298 vaddr_t uref = memtag_strip_tag_vaddr(kaddr); 299 300 uref -= VCORE_START_VA; 301 assert(uref < (UINT32_MAX >> MEMTAG_TAG_WIDTH)); 302 uref |= memtag_get_tag(kaddr) << uref_tag_shift; 303 return uref; 304 } 305 306 assert(((vaddr_t)kaddr - VCORE_START_VA) < UINT32_MAX); 307 return (vaddr_t)kaddr - VCORE_START_VA; 308 } 309 310 vaddr_t uref_to_vaddr(uint32_t uref) 311 { 312 if (MEMTAG_IS_ENABLED) { 313 vaddr_t u = uref & (UINT32_MAX >> MEMTAG_TAG_WIDTH); 314 unsigned int uref_tag_shift = 32 - MEMTAG_TAG_WIDTH; 315 uint8_t tag = uref >> uref_tag_shift; 316 317 return memtag_insert_tag_vaddr(VCORE_START_VA + u, tag); 318 } 319 320 return VCORE_START_VA + uref; 321 } 322