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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 | #include <darwintest.h> #include <darwintest_utils.h> #include <mach/mach_init.h> #include <mach/mach_port.h> #include <mach/vm_map.h> T_GLOBAL_META( T_META_NAMESPACE("xnu.vm"), T_META_RADAR_COMPONENT_NAME("xnu"), T_META_RADAR_COMPONENT_VERSION("VM")); struct context1 { vm_size_t obj_size; vm_address_t e0; mach_port_t mem_entry_ro; mach_port_t mem_entry_rw; dispatch_semaphore_t running_sem; pthread_mutex_t mtx; bool done; }; static void * switcheroo_thread(__unused void *arg) { kern_return_t kr; struct context1 *ctx; ctx = (struct context1 *)arg; /* tell main thread we're ready to run */ dispatch_semaphore_signal(ctx->running_sem); while (!ctx->done) { /* wait for main thread to be done setting things up */ pthread_mutex_lock(&ctx->mtx); if (ctx->done) { break; } /* switch e0 to RW mapping */ kr = vm_map(mach_task_self(), &ctx->e0, ctx->obj_size, 0, /* mask */ VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE, ctx->mem_entry_rw, 0, FALSE, /* copy */ VM_PROT_READ | VM_PROT_WRITE, VM_PROT_READ | VM_PROT_WRITE, VM_INHERIT_DEFAULT); T_QUIET; T_EXPECT_MACH_SUCCESS(kr, " vm_map() RW"); /* wait a little bit */ usleep(100); /* switch bakc to original RO mapping */ kr = vm_map(mach_task_self(), &ctx->e0, ctx->obj_size, 0, /* mask */ VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE, ctx->mem_entry_ro, 0, FALSE, /* copy */ VM_PROT_READ, VM_PROT_READ, VM_INHERIT_DEFAULT); T_QUIET; T_EXPECT_MACH_SUCCESS(kr, " vm_map() RO"); /* tell main thread we're don switching mappings */ pthread_mutex_unlock(&ctx->mtx); usleep(100); } return NULL; } T_DECL(unaligned_copy_switch_race, "Test that unaligned copy respects read-only mapping", T_META_TAG_VM_PREFERRED) { pthread_t th = NULL; int ret; kern_return_t kr; time_t start, duration; mach_msg_type_number_t cow_read_size; vm_size_t copied_size; int loops; vm_address_t e2, e5; struct context1 context1, *ctx; int kern_success = 0, kern_protection_failure = 0, kern_other = 0; vm_address_t ro_addr, tmp_addr; memory_object_size_t mo_size; ctx = &context1; ctx->obj_size = 256 * 1024; ctx->e0 = 0; ctx->running_sem = dispatch_semaphore_create(0); T_QUIET; T_ASSERT_NE(ctx->running_sem, NULL, "dispatch_semaphore_create"); ret = pthread_mutex_init(&ctx->mtx, NULL); T_QUIET; T_ASSERT_POSIX_SUCCESS(ret, "pthread_mutex_init"); ctx->done = false; ctx->mem_entry_rw = MACH_PORT_NULL; ctx->mem_entry_ro = MACH_PORT_NULL; /* allocate our attack target memory */ kr = vm_allocate(mach_task_self(), &ro_addr, ctx->obj_size, VM_FLAGS_ANYWHERE); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "vm_allocate ro_addr"); /* initialize to 'A' */ memset((char *)ro_addr, 'A', ctx->obj_size); /* make it read-only */ kr = vm_protect(mach_task_self(), ro_addr, ctx->obj_size, TRUE, /* set_maximum */ VM_PROT_READ); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "vm_protect ro_addr"); /* make sure we can't get read-write handle on that target memory */ mo_size = ctx->obj_size; kr = mach_make_memory_entry_64(mach_task_self(), &mo_size, ro_addr, MAP_MEM_VM_SHARE | VM_PROT_READ | VM_PROT_WRITE, &ctx->mem_entry_ro, MACH_PORT_NULL); T_QUIET; T_ASSERT_MACH_ERROR(kr, KERN_PROTECTION_FAILURE, "make_mem_entry() RO"); /* take read-only handle on that target memory */ mo_size = ctx->obj_size; kr = mach_make_memory_entry_64(mach_task_self(), &mo_size, ro_addr, MAP_MEM_VM_SHARE | VM_PROT_READ, &ctx->mem_entry_ro, MACH_PORT_NULL); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "make_mem_entry() RO"); T_QUIET; T_ASSERT_EQ(mo_size, (memory_object_size_t)ctx->obj_size, "wrong mem_entry size"); /* make sure we can't map target memory as writable */ tmp_addr = 0; kr = vm_map(mach_task_self(), &tmp_addr, ctx->obj_size, 0, /* mask */ VM_FLAGS_ANYWHERE, ctx->mem_entry_ro, 0, FALSE, /* copy */ VM_PROT_READ, VM_PROT_READ | VM_PROT_WRITE, VM_INHERIT_DEFAULT); T_QUIET; T_EXPECT_MACH_ERROR(kr, KERN_INVALID_RIGHT, " vm_map() mem_entry_rw"); tmp_addr = 0; kr = vm_map(mach_task_self(), &tmp_addr, ctx->obj_size, 0, /* mask */ VM_FLAGS_ANYWHERE, ctx->mem_entry_ro, 0, FALSE, /* copy */ VM_PROT_READ | VM_PROT_WRITE, VM_PROT_READ | VM_PROT_WRITE, VM_INHERIT_DEFAULT); T_QUIET; T_EXPECT_MACH_ERROR(kr, KERN_INVALID_RIGHT, " vm_map() mem_entry_rw"); /* allocate a source buffer for the unaligned copy */ kr = vm_allocate(mach_task_self(), &e5, ctx->obj_size, VM_FLAGS_ANYWHERE); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "vm_allocate e5"); /* initialize to 'C' */ memset((char *)e5, 'C', ctx->obj_size); /* * get a handle on some writable memory that will be temporarily * switched with the read-only mapping of our target memory to try * and trick copy_unaligned to write to our read-only target. */ tmp_addr = 0; kr = vm_allocate(mach_task_self(), &tmp_addr, ctx->obj_size, VM_FLAGS_ANYWHERE); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "vm_allocate() some rw memory"); /* initialize to 'D' */ memset((char *)tmp_addr, 'D', ctx->obj_size); /* get a memory entry handle for that RW memory */ mo_size = ctx->obj_size; kr = mach_make_memory_entry_64(mach_task_self(), &mo_size, tmp_addr, MAP_MEM_VM_SHARE | VM_PROT_READ | VM_PROT_WRITE, &ctx->mem_entry_rw, MACH_PORT_NULL); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "make_mem_entry() RW"); T_QUIET; T_ASSERT_EQ(mo_size, (memory_object_size_t)ctx->obj_size, "wrong mem_entry size"); kr = vm_deallocate(mach_task_self(), tmp_addr, ctx->obj_size); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "vm_deallocate() tmp_addr 0x%llx", (uint64_t)tmp_addr); tmp_addr = 0; pthread_mutex_lock(&ctx->mtx); /* start racing thread */ ret = pthread_create(&th, NULL, switcheroo_thread, (void *)ctx); T_QUIET; T_ASSERT_POSIX_SUCCESS(ret, "pthread_create"); /* wait for racing thread to be ready to run */ dispatch_semaphore_wait(ctx->running_sem, DISPATCH_TIME_FOREVER); duration = 10; /* 10 seconds */ T_LOG("Testing for %ld seconds...", duration); for (start = time(NULL), loops = 0; time(NULL) < start + duration; loops++) { /* reserve space for our 2 contiguous allocations */ e2 = 0; kr = vm_allocate(mach_task_self(), &e2, 2 * ctx->obj_size, VM_FLAGS_ANYWHERE); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "vm_allocate to reserve e2+e0"); /* make 1st allocation in our reserved space */ kr = vm_allocate(mach_task_self(), &e2, ctx->obj_size, VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE | VM_MAKE_TAG(240)); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "vm_allocate e2"); /* initialize to 'B' */ memset((char *)e2, 'B', ctx->obj_size); /* map our read-only target memory right after */ ctx->e0 = e2 + ctx->obj_size; kr = vm_map(mach_task_self(), &ctx->e0, ctx->obj_size, 0, /* mask */ VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE | VM_MAKE_TAG(241), ctx->mem_entry_ro, 0, FALSE, /* copy */ VM_PROT_READ, VM_PROT_READ, VM_INHERIT_DEFAULT); T_QUIET; T_EXPECT_MACH_SUCCESS(kr, " vm_map() mem_entry_ro"); /* let the racing thread go */ pthread_mutex_unlock(&ctx->mtx); /* wait a little bit */ usleep(100); /* trigger copy_unaligned while racing with other thread */ kr = vm_read_overwrite(mach_task_self(), e5, ctx->obj_size, e2 + 1, &copied_size); T_QUIET; T_ASSERT_TRUE(kr == KERN_SUCCESS || kr == KERN_PROTECTION_FAILURE, "vm_read_overwrite kr %d", kr); switch (kr) { case KERN_SUCCESS: /* the target was RW */ kern_success++; break; case KERN_PROTECTION_FAILURE: /* the target was RO */ kern_protection_failure++; break; default: /* should not happen */ kern_other++; break; } /* check that our read-only memory was not modified */ T_QUIET; T_ASSERT_EQ(*(char *)ro_addr, 'A', "RO mapping was modified"); /* tell racing thread to stop toggling mappings */ pthread_mutex_lock(&ctx->mtx); /* clean up before next loop */ vm_deallocate(mach_task_self(), ctx->e0, ctx->obj_size); ctx->e0 = 0; vm_deallocate(mach_task_self(), e2, ctx->obj_size); e2 = 0; } ctx->done = true; pthread_mutex_unlock(&ctx->mtx); pthread_join(th, NULL); kr = mach_port_deallocate(mach_task_self(), ctx->mem_entry_rw); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "mach_port_deallocate(me_rw)"); kr = mach_port_deallocate(mach_task_self(), ctx->mem_entry_ro); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "mach_port_deallocate(me_ro)"); kr = vm_deallocate(mach_task_self(), ro_addr, ctx->obj_size); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "vm_deallocate(ro_addr)"); kr = vm_deallocate(mach_task_self(), e5, ctx->obj_size); T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "vm_deallocate(e5)"); T_LOG("vm_read_overwrite: KERN_SUCCESS:%d KERN_PROTECTION_FAILURE:%d other:%d", kern_success, kern_protection_failure, kern_other); T_PASS("Ran %d times in %ld seconds with no failure", loops, duration); } |