exec_subr.c revision 1.71.6.4
1 /* $NetBSD: exec_subr.c,v 1.71.6.4 2017/08/28 17:53:07 skrll Exp $ */ 2 3 /* 4 * Copyright (c) 1993, 1994, 1996 Christopher G. Demetriou 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Christopher G. Demetriou. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __KERNEL_RCSID(0, "$NetBSD: exec_subr.c,v 1.71.6.4 2017/08/28 17:53:07 skrll Exp $"); 35 36 #include "opt_pax.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/proc.h> 41 #include <sys/kmem.h> 42 #include <sys/vnode.h> 43 #include <sys/filedesc.h> 44 #include <sys/exec.h> 45 #include <sys/mman.h> 46 #include <sys/resourcevar.h> 47 #include <sys/device.h> 48 #include <sys/pax.h> 49 50 #include <uvm/uvm_extern.h> 51 52 #define VMCMD_EVCNT_DECL(name) \ 53 static struct evcnt vmcmd_ev_##name = \ 54 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "vmcmd", #name); \ 55 EVCNT_ATTACH_STATIC(vmcmd_ev_##name) 56 57 #define VMCMD_EVCNT_INCR(name) \ 58 vmcmd_ev_##name.ev_count++ 59 60 VMCMD_EVCNT_DECL(calls); 61 VMCMD_EVCNT_DECL(extends); 62 VMCMD_EVCNT_DECL(kills); 63 64 #ifdef DEBUG_STACK 65 #define DPRINTF(a) uprintf a 66 #else 67 #define DPRINTF(a) 68 #endif 69 70 unsigned int user_stack_guard_size = 1024 * 1024; 71 unsigned int user_thread_stack_guard_size = 64 * 1024; 72 73 /* 74 * new_vmcmd(): 75 * create a new vmcmd structure and fill in its fields based 76 * on function call arguments. make sure objects ref'd by 77 * the vmcmd are 'held'. 78 */ 79 80 void 81 new_vmcmd(struct exec_vmcmd_set *evsp, 82 int (*proc)(struct lwp * l, struct exec_vmcmd *), 83 vsize_t len, vaddr_t addr, struct vnode *vp, u_long offset, 84 u_int prot, int flags) 85 { 86 struct exec_vmcmd *vcp; 87 88 VMCMD_EVCNT_INCR(calls); 89 KASSERT(proc != vmcmd_map_pagedvn || (vp->v_iflag & VI_TEXT)); 90 KASSERT(vp == NULL || vp->v_usecount > 0); 91 92 if (evsp->evs_used >= evsp->evs_cnt) 93 vmcmdset_extend(evsp); 94 vcp = &evsp->evs_cmds[evsp->evs_used++]; 95 vcp->ev_proc = proc; 96 vcp->ev_len = len; 97 vcp->ev_addr = addr; 98 if ((vcp->ev_vp = vp) != NULL) 99 vref(vp); 100 vcp->ev_offset = offset; 101 vcp->ev_prot = prot; 102 vcp->ev_flags = flags; 103 } 104 105 void 106 vmcmdset_extend(struct exec_vmcmd_set *evsp) 107 { 108 struct exec_vmcmd *nvcp; 109 u_int ocnt; 110 111 #ifdef DIAGNOSTIC 112 if (evsp->evs_used < evsp->evs_cnt) 113 panic("vmcmdset_extend: not necessary"); 114 #endif 115 116 /* figure out number of entries in new set */ 117 if ((ocnt = evsp->evs_cnt) != 0) { 118 evsp->evs_cnt += ocnt; 119 VMCMD_EVCNT_INCR(extends); 120 } else 121 evsp->evs_cnt = EXEC_DEFAULT_VMCMD_SETSIZE; 122 123 /* allocate it */ 124 nvcp = kmem_alloc(evsp->evs_cnt * sizeof(struct exec_vmcmd), KM_SLEEP); 125 126 /* free the old struct, if there was one, and record the new one */ 127 if (ocnt) { 128 memcpy(nvcp, evsp->evs_cmds, 129 (ocnt * sizeof(struct exec_vmcmd))); 130 kmem_free(evsp->evs_cmds, ocnt * sizeof(struct exec_vmcmd)); 131 } 132 evsp->evs_cmds = nvcp; 133 } 134 135 void 136 kill_vmcmds(struct exec_vmcmd_set *evsp) 137 { 138 struct exec_vmcmd *vcp; 139 u_int i; 140 141 VMCMD_EVCNT_INCR(kills); 142 143 if (evsp->evs_cnt == 0) 144 return; 145 146 for (i = 0; i < evsp->evs_used; i++) { 147 vcp = &evsp->evs_cmds[i]; 148 if (vcp->ev_vp != NULL) 149 vrele(vcp->ev_vp); 150 } 151 kmem_free(evsp->evs_cmds, evsp->evs_cnt * sizeof(struct exec_vmcmd)); 152 evsp->evs_used = evsp->evs_cnt = 0; 153 } 154 155 /* 156 * vmcmd_map_pagedvn(): 157 * handle vmcmd which specifies that a vnode should be mmap'd. 158 * appropriate for handling demand-paged text and data segments. 159 */ 160 161 static int 162 vmcmd_get_prot(struct lwp *l, const struct exec_vmcmd *cmd, vm_prot_t *prot, 163 vm_prot_t *maxprot) 164 { 165 166 *prot = cmd->ev_prot; 167 *maxprot = PAX_MPROTECT_MAXPROTECT(l, *prot, 0, UVM_PROT_ALL); 168 169 if ((*prot & *maxprot) != *prot) 170 return EACCES; 171 return PAX_MPROTECT_VALIDATE(l, *prot); 172 } 173 174 int 175 vmcmd_map_pagedvn(struct lwp *l, struct exec_vmcmd *cmd) 176 { 177 struct uvm_object *uobj; 178 struct vnode *vp = cmd->ev_vp; 179 struct proc *p = l->l_proc; 180 int error; 181 vm_prot_t prot, maxprot; 182 183 KASSERT(vp->v_iflag & VI_TEXT); 184 185 /* 186 * map the vnode in using uvm_map. 187 */ 188 189 if (cmd->ev_len == 0) 190 return 0; 191 if (cmd->ev_offset & PAGE_MASK) 192 return EINVAL; 193 if (cmd->ev_addr & PAGE_MASK) 194 return EINVAL; 195 if (cmd->ev_len & PAGE_MASK) 196 return EINVAL; 197 198 if ((error = vmcmd_get_prot(l, cmd, &prot, &maxprot)) != 0) 199 return error; 200 201 /* 202 * check the file system's opinion about mmapping the file 203 */ 204 205 error = VOP_MMAP(vp, prot, l->l_cred); 206 if (error) 207 return error; 208 209 if ((vp->v_vflag & VV_MAPPED) == 0) { 210 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 211 vp->v_vflag |= VV_MAPPED; 212 VOP_UNLOCK(vp); 213 } 214 215 /* 216 * do the map, reference the object for this map entry 217 */ 218 uobj = &vp->v_uobj; 219 vref(vp); 220 221 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, cmd->ev_len, 222 uobj, cmd->ev_offset, 0, 223 UVM_MAPFLAG(prot, maxprot, UVM_INH_COPY, 224 UVM_ADV_NORMAL, UVM_FLAG_COPYONW|UVM_FLAG_FIXED)); 225 if (error) { 226 uobj->pgops->pgo_detach(uobj); 227 } 228 return error; 229 } 230 231 /* 232 * vmcmd_map_readvn(): 233 * handle vmcmd which specifies that a vnode should be read from. 234 * appropriate for non-demand-paged text/data segments, i.e. impure 235 * objects (a la OMAGIC and NMAGIC). 236 */ 237 int 238 vmcmd_map_readvn(struct lwp *l, struct exec_vmcmd *cmd) 239 { 240 struct proc *p = l->l_proc; 241 int error; 242 long diff; 243 244 if (cmd->ev_len == 0) 245 return 0; 246 247 diff = cmd->ev_addr - trunc_page(cmd->ev_addr); 248 cmd->ev_addr -= diff; /* required by uvm_map */ 249 cmd->ev_offset -= diff; 250 cmd->ev_len += diff; 251 252 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, 253 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, 254 UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY, 255 UVM_ADV_NORMAL, 256 UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)); 257 258 if (error) 259 return error; 260 261 return vmcmd_readvn(l, cmd); 262 } 263 264 int 265 vmcmd_readvn(struct lwp *l, struct exec_vmcmd *cmd) 266 { 267 struct proc *p = l->l_proc; 268 int error; 269 vm_prot_t prot, maxprot; 270 271 error = vn_rdwr(UIO_READ, cmd->ev_vp, (void *)cmd->ev_addr, 272 cmd->ev_len, cmd->ev_offset, UIO_USERSPACE, IO_UNIT, 273 l->l_cred, NULL, l); 274 if (error) 275 return error; 276 277 if ((error = vmcmd_get_prot(l, cmd, &prot, &maxprot)) != 0) 278 return error; 279 280 #ifdef PMAP_NEED_PROCWR 281 /* 282 * we had to write the process, make sure the pages are synched 283 * with the instruction cache. 284 */ 285 if (prot & VM_PROT_EXECUTE) 286 pmap_procwr(p, cmd->ev_addr, cmd->ev_len); 287 #endif 288 289 /* 290 * we had to map in the area at PROT_ALL so that vn_rdwr() 291 * could write to it. however, the caller seems to want 292 * it mapped read-only, so now we are going to have to call 293 * uvm_map_protect() to fix up the protection. ICK. 294 */ 295 if (maxprot != VM_PROT_ALL) { 296 error = uvm_map_protect(&p->p_vmspace->vm_map, 297 trunc_page(cmd->ev_addr), 298 round_page(cmd->ev_addr + cmd->ev_len), 299 maxprot, true); 300 if (error) 301 return error; 302 } 303 304 if (prot != maxprot) { 305 error = uvm_map_protect(&p->p_vmspace->vm_map, 306 trunc_page(cmd->ev_addr), 307 round_page(cmd->ev_addr + cmd->ev_len), 308 prot, false); 309 if (error) 310 return error; 311 } 312 313 return 0; 314 } 315 316 /* 317 * vmcmd_map_zero(): 318 * handle vmcmd which specifies a zero-filled address space region. The 319 * address range must be first allocated, then protected appropriately. 320 */ 321 322 int 323 vmcmd_map_zero(struct lwp *l, struct exec_vmcmd *cmd) 324 { 325 struct proc *p = l->l_proc; 326 int error; 327 long diff; 328 vm_prot_t prot, maxprot; 329 330 diff = cmd->ev_addr - trunc_page(cmd->ev_addr); 331 cmd->ev_addr -= diff; /* required by uvm_map */ 332 cmd->ev_len += diff; 333 334 if ((error = vmcmd_get_prot(l, cmd, &prot, &maxprot)) != 0) 335 return error; 336 337 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, 338 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, 339 UVM_MAPFLAG(prot, maxprot, UVM_INH_COPY, 340 UVM_ADV_NORMAL, 341 UVM_FLAG_FIXED|UVM_FLAG_COPYONW)); 342 if (cmd->ev_flags & VMCMD_STACK) 343 curproc->p_vmspace->vm_issize += atop(round_page(cmd->ev_len)); 344 return error; 345 } 346 347 /* 348 * exec_read_from(): 349 * 350 * Read from vnode into buffer at offset. 351 */ 352 int 353 exec_read_from(struct lwp *l, struct vnode *vp, u_long off, void *bf, 354 size_t size) 355 { 356 int error; 357 size_t resid; 358 359 if ((error = vn_rdwr(UIO_READ, vp, bf, size, off, UIO_SYSSPACE, 360 0, l->l_cred, &resid, NULL)) != 0) 361 return error; 362 /* 363 * See if we got all of it 364 */ 365 if (resid != 0) 366 return ENOEXEC; 367 return 0; 368 } 369 370 /* 371 * exec_setup_stack(): Set up the stack segment for an elf 372 * executable. 373 * 374 * Note that the ep_ssize parameter must be set to be the current stack 375 * limit; this is adjusted in the body of execve() to yield the 376 * appropriate stack segment usage once the argument length is 377 * calculated. 378 * 379 * This function returns an int for uniformity with other (future) formats' 380 * stack setup functions. They might have errors to return. 381 */ 382 383 int 384 exec_setup_stack(struct lwp *l, struct exec_package *epp) 385 { 386 vsize_t max_stack_size; 387 vaddr_t access_linear_min; 388 vsize_t access_size; 389 vaddr_t noaccess_linear_min; 390 vsize_t noaccess_size; 391 392 #ifndef USRSTACK32 393 #define USRSTACK32 (0x00000000ffffffffL&~PGOFSET) 394 #endif 395 #ifndef MAXSSIZ32 396 #define MAXSSIZ32 (MAXSSIZ >> 2) 397 #endif 398 399 if (epp->ep_flags & EXEC_32) { 400 epp->ep_minsaddr = USRSTACK32; 401 max_stack_size = MAXSSIZ32; 402 } else { 403 epp->ep_minsaddr = USRSTACK; 404 max_stack_size = MAXSSIZ; 405 } 406 407 DPRINTF(("ep_minsaddr=%#jx max_stack_size=%#jx\n", 408 (uintmax_t)epp->ep_minsaddr, (uintmax_t)max_stack_size)); 409 410 pax_aslr_stack(epp, &max_stack_size); 411 412 DPRINTF(("[RLIMIT_STACK].lim_cur=%#jx max_stack_size=%#jx\n", 413 (uintmax_t)l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur, 414 (uintmax_t)max_stack_size)); 415 epp->ep_ssize = MIN(l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur, 416 max_stack_size); 417 418 l->l_proc->p_stackbase = epp->ep_minsaddr; 419 420 epp->ep_maxsaddr = (vaddr_t)STACK_GROW(epp->ep_minsaddr, 421 max_stack_size); 422 423 DPRINTF(("ep_ssize=%#jx ep_minsaddr=%#jx ep_maxsaddr=%#jx\n", 424 (uintmax_t)epp->ep_ssize, (uintmax_t)epp->ep_minsaddr, 425 (uintmax_t)epp->ep_maxsaddr)); 426 427 /* 428 * set up commands for stack. note that this takes *two*, one to 429 * map the part of the stack which we can access, and one to map 430 * the part which we can't. 431 * 432 * arguably, it could be made into one, but that would require the 433 * addition of another mapping proc, which is unnecessary 434 */ 435 access_size = epp->ep_ssize; 436 access_linear_min = (vaddr_t)STACK_ALLOC(epp->ep_minsaddr, access_size); 437 noaccess_size = max_stack_size - access_size; 438 noaccess_linear_min = (vaddr_t)STACK_ALLOC(STACK_GROW(epp->ep_minsaddr, 439 access_size), noaccess_size); 440 441 DPRINTF(("access_size=%#jx, access_linear_min=%#jx, " 442 "noaccess_size=%#jx, noaccess_linear_min=%#jx\n", 443 (uintmax_t)access_size, (uintmax_t)access_linear_min, 444 (uintmax_t)noaccess_size, (uintmax_t)noaccess_linear_min)); 445 446 if (user_stack_guard_size > 0) { 447 #ifdef __MACHINE_STACK_GROWS_UP 448 vsize_t guard_size = MIN(VM_MAXUSER_ADDRESS - epp->ep_maxsaddr, user_stack_guard_size); 449 if (guard_size > 0) 450 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, guard_size, 451 epp->ep_maxsaddr, NULL, 0, VM_PROT_NONE); 452 #else 453 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, user_stack_guard_size, 454 epp->ep_maxsaddr - user_stack_guard_size, NULL, 0, VM_PROT_NONE); 455 #endif 456 } 457 if (noaccess_size > 0 && noaccess_size <= MAXSSIZ) { 458 NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, noaccess_size, 459 noaccess_linear_min, NULL, 0, VM_PROT_NONE, VMCMD_STACK); 460 } 461 KASSERT(access_size > 0 && access_size <= MAXSSIZ); 462 NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, access_size, 463 access_linear_min, NULL, 0, VM_PROT_READ | VM_PROT_WRITE, 464 VMCMD_STACK); 465 466 return 0; 467 } 468
Indexes created Tue Sep 23 14:10:03 GMT 2025