1 /* $NetBSD: exec_subr.c,v 1.67 2011/01/17 07:13:31 uebayasi 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 1.67 2011/01/17 07:13:31 uebayasi 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 49 #ifdef PAX_MPROTECT 50 #include <sys/pax.h> 51 #endif /* PAX_MPROTECT */ 52 53 #include <uvm/uvm_extern.h> 54 55 #define VMCMD_EVCNT_DECL(name) \ 56 static struct evcnt vmcmd_ev_##name = \ 57 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "vmcmd", #name); \ 58 EVCNT_ATTACH_STATIC(vmcmd_ev_##name) 59 60 #define VMCMD_EVCNT_INCR(name) \ 61 vmcmd_ev_##name.ev_count++ 62 63 VMCMD_EVCNT_DECL(calls); 64 VMCMD_EVCNT_DECL(extends); 65 VMCMD_EVCNT_DECL(kills); 66 67 /* 68 * new_vmcmd(): 69 * create a new vmcmd structure and fill in its fields based 70 * on function call arguments. make sure objects ref'd by 71 * the vmcmd are 'held'. 72 */ 73 74 void 75 new_vmcmd(struct exec_vmcmd_set *evsp, 76 int (*proc)(struct lwp * l, struct exec_vmcmd *), 77 vsize_t len, vaddr_t addr, struct vnode *vp, u_long offset, 78 u_int prot, int flags) 79 { 80 struct exec_vmcmd *vcp; 81 82 VMCMD_EVCNT_INCR(calls); 83 KASSERT(proc != vmcmd_map_pagedvn || (vp->v_iflag & VI_TEXT)); 84 KASSERT(vp == NULL || vp->v_usecount > 0); 85 86 if (evsp->evs_used >= evsp->evs_cnt) 87 vmcmdset_extend(evsp); 88 vcp = &evsp->evs_cmds[evsp->evs_used++]; 89 vcp->ev_proc = proc; 90 vcp->ev_len = len; 91 vcp->ev_addr = addr; 92 if ((vcp->ev_vp = vp) != NULL) 93 vref(vp); 94 vcp->ev_offset = offset; 95 vcp->ev_prot = prot; 96 vcp->ev_flags = flags; 97 } 98 99 void 100 vmcmdset_extend(struct exec_vmcmd_set *evsp) 101 { 102 struct exec_vmcmd *nvcp; 103 u_int ocnt; 104 105 #ifdef DIAGNOSTIC 106 if (evsp->evs_used < evsp->evs_cnt) 107 panic("vmcmdset_extend: not necessary"); 108 #endif 109 110 /* figure out number of entries in new set */ 111 if ((ocnt = evsp->evs_cnt) != 0) { 112 evsp->evs_cnt += ocnt; 113 VMCMD_EVCNT_INCR(extends); 114 } else 115 evsp->evs_cnt = EXEC_DEFAULT_VMCMD_SETSIZE; 116 117 /* allocate it */ 118 nvcp = kmem_alloc(evsp->evs_cnt * sizeof(struct exec_vmcmd), KM_SLEEP); 119 120 /* free the old struct, if there was one, and record the new one */ 121 if (ocnt) { 122 memcpy(nvcp, evsp->evs_cmds, 123 (ocnt * sizeof(struct exec_vmcmd))); 124 kmem_free(evsp->evs_cmds, ocnt * sizeof(struct exec_vmcmd)); 125 } 126 evsp->evs_cmds = nvcp; 127 } 128 129 void 130 kill_vmcmds(struct exec_vmcmd_set *evsp) 131 { 132 struct exec_vmcmd *vcp; 133 u_int i; 134 135 VMCMD_EVCNT_INCR(kills); 136 137 if (evsp->evs_cnt == 0) 138 return; 139 140 for (i = 0; i < evsp->evs_used; i++) { 141 vcp = &evsp->evs_cmds[i]; 142 if (vcp->ev_vp != NULL) 143 vrele(vcp->ev_vp); 144 } 145 kmem_free(evsp->evs_cmds, evsp->evs_cnt * sizeof(struct exec_vmcmd)); 146 evsp->evs_used = evsp->evs_cnt = 0; 147 } 148 149 /* 150 * vmcmd_map_pagedvn(): 151 * handle vmcmd which specifies that a vnode should be mmap'd. 152 * appropriate for handling demand-paged text and data segments. 153 */ 154 155 int 156 vmcmd_map_pagedvn(struct lwp *l, struct exec_vmcmd *cmd) 157 { 158 struct uvm_object *uobj; 159 struct vnode *vp = cmd->ev_vp; 160 struct proc *p = l->l_proc; 161 int error; 162 vm_prot_t prot, maxprot; 163 164 KASSERT(vp->v_iflag & VI_TEXT); 165 166 /* 167 * map the vnode in using uvm_map. 168 */ 169 170 if (cmd->ev_len == 0) 171 return(0); 172 if (cmd->ev_offset & PAGE_MASK) 173 return(EINVAL); 174 if (cmd->ev_addr & PAGE_MASK) 175 return(EINVAL); 176 if (cmd->ev_len & PAGE_MASK) 177 return(EINVAL); 178 179 prot = cmd->ev_prot; 180 maxprot = UVM_PROT_ALL; 181 #ifdef PAX_MPROTECT 182 pax_mprotect(l, &prot, &maxprot); 183 #endif /* PAX_MPROTECT */ 184 185 /* 186 * check the file system's opinion about mmapping the file 187 */ 188 189 error = VOP_MMAP(vp, prot, l->l_cred); 190 if (error) 191 return error; 192 193 if ((vp->v_vflag & VV_MAPPED) == 0) { 194 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 195 vp->v_vflag |= VV_MAPPED; 196 VOP_UNLOCK(vp); 197 } 198 199 /* 200 * do the map, reference the object for this map entry 201 */ 202 uobj = &vp->v_uobj; 203 vref(vp); 204 205 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, cmd->ev_len, 206 uobj, cmd->ev_offset, 0, 207 UVM_MAPFLAG(prot, maxprot, UVM_INH_COPY, 208 UVM_ADV_NORMAL, UVM_FLAG_COPYONW|UVM_FLAG_FIXED)); 209 if (error) { 210 uobj->pgops->pgo_detach(uobj); 211 } 212 return error; 213 } 214 215 /* 216 * vmcmd_map_readvn(): 217 * handle vmcmd which specifies that a vnode should be read from. 218 * appropriate for non-demand-paged text/data segments, i.e. impure 219 * objects (a la OMAGIC and NMAGIC). 220 */ 221 int 222 vmcmd_map_readvn(struct lwp *l, struct exec_vmcmd *cmd) 223 { 224 struct proc *p = l->l_proc; 225 int error; 226 long diff; 227 228 if (cmd->ev_len == 0) 229 return 0; 230 231 diff = cmd->ev_addr - trunc_page(cmd->ev_addr); 232 cmd->ev_addr -= diff; /* required by uvm_map */ 233 cmd->ev_offset -= diff; 234 cmd->ev_len += diff; 235 236 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, 237 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, 238 UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY, 239 UVM_ADV_NORMAL, 240 UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)); 241 242 if (error) 243 return error; 244 245 return vmcmd_readvn(l, cmd); 246 } 247 248 int 249 vmcmd_readvn(struct lwp *l, struct exec_vmcmd *cmd) 250 { 251 struct proc *p = l->l_proc; 252 int error; 253 vm_prot_t prot, maxprot; 254 255 error = vn_rdwr(UIO_READ, cmd->ev_vp, (void *)cmd->ev_addr, 256 cmd->ev_len, cmd->ev_offset, UIO_USERSPACE, IO_UNIT, 257 l->l_cred, NULL, l); 258 if (error) 259 return error; 260 261 prot = cmd->ev_prot; 262 maxprot = VM_PROT_ALL; 263 #ifdef PAX_MPROTECT 264 pax_mprotect(l, &prot, &maxprot); 265 #endif /* PAX_MPROTECT */ 266 267 #ifdef PMAP_NEED_PROCWR 268 /* 269 * we had to write the process, make sure the pages are synched 270 * with the instruction cache. 271 */ 272 if (prot & VM_PROT_EXECUTE) 273 pmap_procwr(p, cmd->ev_addr, cmd->ev_len); 274 #endif 275 276 /* 277 * we had to map in the area at PROT_ALL so that vn_rdwr() 278 * could write to it. however, the caller seems to want 279 * it mapped read-only, so now we are going to have to call 280 * uvm_map_protect() to fix up the protection. ICK. 281 */ 282 if (maxprot != VM_PROT_ALL) { 283 error = uvm_map_protect(&p->p_vmspace->vm_map, 284 trunc_page(cmd->ev_addr), 285 round_page(cmd->ev_addr + cmd->ev_len), 286 maxprot, true); 287 if (error) 288 return (error); 289 } 290 291 if (prot != maxprot) { 292 error = uvm_map_protect(&p->p_vmspace->vm_map, 293 trunc_page(cmd->ev_addr), 294 round_page(cmd->ev_addr + cmd->ev_len), 295 prot, false); 296 if (error) 297 return (error); 298 } 299 300 return 0; 301 } 302 303 /* 304 * vmcmd_map_zero(): 305 * handle vmcmd which specifies a zero-filled address space region. The 306 * address range must be first allocated, then protected appropriately. 307 */ 308 309 int 310 vmcmd_map_zero(struct lwp *l, struct exec_vmcmd *cmd) 311 { 312 struct proc *p = l->l_proc; 313 int error; 314 long diff; 315 vm_prot_t prot, maxprot; 316 317 diff = cmd->ev_addr - trunc_page(cmd->ev_addr); 318 cmd->ev_addr -= diff; /* required by uvm_map */ 319 cmd->ev_len += diff; 320 321 prot = cmd->ev_prot; 322 maxprot = UVM_PROT_ALL; 323 #ifdef PAX_MPROTECT 324 pax_mprotect(l, &prot, &maxprot); 325 #endif /* PAX_MPROTECT */ 326 327 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, 328 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, 329 UVM_MAPFLAG(prot, maxprot, UVM_INH_COPY, 330 UVM_ADV_NORMAL, 331 UVM_FLAG_FIXED|UVM_FLAG_COPYONW)); 332 if (cmd->ev_flags & VMCMD_STACK) 333 curproc->p_vmspace->vm_issize += atop(round_page(cmd->ev_len)); 334 return error; 335 } 336 337 /* 338 * exec_read_from(): 339 * 340 * Read from vnode into buffer at offset. 341 */ 342 int 343 exec_read_from(struct lwp *l, struct vnode *vp, u_long off, void *bf, 344 size_t size) 345 { 346 int error; 347 size_t resid; 348 349 if ((error = vn_rdwr(UIO_READ, vp, bf, size, off, UIO_SYSSPACE, 350 0, l->l_cred, &resid, NULL)) != 0) 351 return error; 352 /* 353 * See if we got all of it 354 */ 355 if (resid != 0) 356 return ENOEXEC; 357 return 0; 358 } 359 360 /* 361 * exec_setup_stack(): Set up the stack segment for an elf 362 * executable. 363 * 364 * Note that the ep_ssize parameter must be set to be the current stack 365 * limit; this is adjusted in the body of execve() to yield the 366 * appropriate stack segment usage once the argument length is 367 * calculated. 368 * 369 * This function returns an int for uniformity with other (future) formats' 370 * stack setup functions. They might have errors to return. 371 */ 372 373 int 374 exec_setup_stack(struct lwp *l, struct exec_package *epp) 375 { 376 vsize_t max_stack_size; 377 vaddr_t access_linear_min; 378 vsize_t access_size; 379 vaddr_t noaccess_linear_min; 380 vsize_t noaccess_size; 381 382 #ifndef USRSTACK32 383 #define USRSTACK32 (0x00000000ffffffffL&~PGOFSET) 384 #endif 385 386 if (epp->ep_flags & EXEC_32) { 387 epp->ep_minsaddr = USRSTACK32; 388 max_stack_size = MAXSSIZ; 389 } else { 390 epp->ep_minsaddr = USRSTACK; 391 max_stack_size = MAXSSIZ; 392 } 393 epp->ep_ssize = l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur; 394 395 #ifdef PAX_ASLR 396 pax_aslr_stack(l, epp, &max_stack_size); 397 #endif /* PAX_ASLR */ 398 399 l->l_proc->p_stackbase = epp->ep_minsaddr; 400 401 epp->ep_maxsaddr = (vaddr_t)STACK_GROW(epp->ep_minsaddr, 402 max_stack_size); 403 404 /* 405 * set up commands for stack. note that this takes *two*, one to 406 * map the part of the stack which we can access, and one to map 407 * the part which we can't. 408 * 409 * arguably, it could be made into one, but that would require the 410 * addition of another mapping proc, which is unnecessary 411 */ 412 access_size = epp->ep_ssize; 413 access_linear_min = (vaddr_t)STACK_ALLOC(epp->ep_minsaddr, access_size); 414 noaccess_size = max_stack_size - access_size; 415 noaccess_linear_min = (vaddr_t)STACK_ALLOC(STACK_GROW(epp->ep_minsaddr, 416 access_size), noaccess_size); 417 if (noaccess_size > 0 && noaccess_size <= MAXSSIZ) { 418 NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, noaccess_size, 419 noaccess_linear_min, NULL, 0, VM_PROT_NONE, VMCMD_STACK); 420 } 421 KASSERT(access_size > 0 && access_size <= MAXSSIZ); 422 NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, access_size, 423 access_linear_min, NULL, 0, VM_PROT_READ | VM_PROT_WRITE, 424 VMCMD_STACK); 425 426 return 0; 427 } 428