47 48#include <vm/vm.h> 49#include <vm/vm_param.h> 50#include <vm/vm_prot.h> 51#include <vm/lock.h> 52#include <vm/pmap.h> 53#include <vm/vm_map.h> 54#include <vm/vm_kern.h> 55#include <vm/vm_extern.h> 56 57#include <machine/reg.h> 58 59static int *exec_copyout_strings __P((struct image_params *)); 60 61static int exec_check_permissions(struct image_params *); 62 63/* 64 * XXX trouble here if sizeof(caddr_t) != sizeof(int), other parts 65 * of the sysctl code also assumes this, and sizeof(int) == sizeof(long). 66 */ 67static caddr_t ps_strings = (caddr_t)PS_STRINGS; 68SYSCTL_INT(_kern, KERN_PS_STRINGS, ps_strings, 0, &ps_strings, 0, ""); 69 70static caddr_t usrstack = (caddr_t)USRSTACK; 71SYSCTL_INT(_kern, KERN_USRSTACK, usrstack, 0, &usrstack, 0, ""); 72 73/* 74 * execsw_set is constructed for us by the linker. Each of the items 75 * is a pointer to a `const struct execsw', hence the double pointer here. 76 */ 77static const struct execsw **execsw = 78 (const struct execsw **)&execsw_set.ls_items[0]; 79 80#ifndef _SYS_SYSPROTO_H_ 81struct execve_args { 82 char *fname; 83 char **argv; 84 char **envv; 85}; 86#endif 87 88/* 89 * execve() system call. 90 */ 91int 92execve(p, uap, retval) 93 struct proc *p; 94 register struct execve_args *uap; 95 int *retval; 96{ 97 struct nameidata nd, *ndp; 98 int *stack_base; 99 int error, len, i; 100 struct image_params image_params, *imgp; 101 struct vattr attr; 102 103 imgp = &image_params; 104 105 /* 106 * Initialize part of the common data 107 */ 108 imgp->proc = p; 109 imgp->uap = uap; 110 imgp->attr = &attr; 111 imgp->image_header = NULL; 112 imgp->argc = imgp->envc = 0; 113 imgp->entry_addr = 0; 114 imgp->vmspace_destroyed = 0; 115 imgp->interpreted = 0; 116 imgp->interpreter_name[0] = '\0'; 117 imgp->auxargs = NULL; 118 119 /* 120 * Allocate temporary demand zeroed space for argument and 121 * environment strings 122 */ 123 imgp->stringbase = (char *)kmem_alloc_pageable(exec_map, ARG_MAX); 124 if (imgp->stringbase == NULL) { 125 error = ENOMEM; 126 goto exec_fail; 127 } 128 imgp->stringp = imgp->stringbase; 129 imgp->stringspace = ARG_MAX; 130 131 /* 132 * Translate the file name. namei() returns a vnode pointer 133 * in ni_vp amoung other things. 134 */ 135 ndp = &nd; 136 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 137 UIO_USERSPACE, uap->fname, p); 138 139interpret: 140 141 error = namei(ndp); 142 if (error) { 143 kmem_free(exec_map, (vm_offset_t)imgp->stringbase, ARG_MAX); 144 goto exec_fail; 145 } 146 147 imgp->vp = ndp->ni_vp; 148 if (imgp->vp == NULL) { 149 error = ENOEXEC; 150 goto exec_fail_dealloc; 151 } 152 153 /* 154 * Check file permissions (also 'opens' file) 155 */ 156 error = exec_check_permissions(imgp); 157 158 /* 159 * Lose the lock on the vnode. It's no longer needed, and must not 160 * exist for the pagefault paging to work below. 161 */ 162 VOP_UNLOCK(imgp->vp); 163 164 if (error) 165 goto exec_fail_dealloc; 166 167 /* 168 * Map the image header (first page) of the file into 169 * kernel address space 170 */ 171 error = vm_mmap(kernel_map, /* map */ 172 (vm_offset_t *)&imgp->image_header, /* address */ 173 PAGE_SIZE, /* size */ 174 VM_PROT_READ, /* protection */ 175 VM_PROT_READ, /* max protection */ 176 0, /* flags */ 177 (caddr_t)imgp->vp, /* vnode */ 178 0); /* offset */ 179 if (error) { 180 uprintf("mmap failed: %d\n",error); 181 goto exec_fail_dealloc; 182 } 183 184 /* 185 * Loop through list of image activators, calling each one. 186 * If there is no match, the activator returns -1. If there 187 * is a match, but there was an error during the activation, 188 * the error is returned. Otherwise 0 means success. If the 189 * image is interpreted, loop back up and try activating 190 * the interpreter. 191 */ 192 for (i = 0; execsw[i]; ++i) { 193 if (execsw[i]->ex_imgact) 194 error = (*execsw[i]->ex_imgact)(imgp); 195 else 196 continue; 197 198 if (error == -1) 199 continue; 200 if (error) 201 goto exec_fail_dealloc; 202 if (imgp->interpreted) { 203 /* free old vnode and name buffer */ 204 vrele(ndp->ni_vp); 205 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 206 if (vm_map_remove(kernel_map, (vm_offset_t)imgp->image_header, 207 (vm_offset_t)imgp->image_header + PAGE_SIZE)) 208 panic("execve: header dealloc failed (1)"); 209 210 /* set new name to that of the interpreter */ 211 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 212 UIO_SYSSPACE, imgp->interpreter_name, p); 213 goto interpret; 214 } 215 break; 216 } 217 /* If we made it through all the activators and none matched, exit. */ 218 if (error == -1) { 219 error = ENOEXEC; 220 goto exec_fail_dealloc; 221 } 222 223 /* 224 * Copy out strings (args and env) and initialize stack base 225 */ 226 stack_base = exec_copyout_strings(imgp); 227 p->p_vmspace->vm_minsaddr = (char *)stack_base; 228 229 /* 230 * If custom stack fixup routine present for this process 231 * let it do the stack setup. 232 * Else stuff argument count as first item on stack 233 */ 234 if (p->p_sysent->sv_fixup) 235 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 236 else 237 suword(--stack_base, imgp->argc); 238 239 /* close files on exec */ 240 fdcloseexec(p); 241 242 /* reset caught signals */ 243 execsigs(p); 244 245 /* name this process - nameiexec(p, ndp) */ 246 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 247 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 248 p->p_comm[len] = 0; 249 250 /* 251 * mark as execed, wakeup the process that vforked (if any) and tell 252 * it that it now has it's own resources back 253 */ 254 p->p_flag |= P_EXEC; 255 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 256 p->p_flag &= ~P_PPWAIT; 257 wakeup((caddr_t)p->p_pptr); 258 } 259 260 /* 261 * Implement image setuid/setgid. Disallow if the process is 262 * being traced. 263 */ 264 if ((attr.va_mode & (VSUID | VSGID)) && 265 (p->p_flag & P_TRACED) == 0) { 266 /* 267 * Turn off syscall tracing for set-id programs, except for 268 * root. 269 */ 270 if (p->p_tracep && suser(p->p_ucred, &p->p_acflag)) { 271 p->p_traceflag = 0; 272 vrele(p->p_tracep); 273 p->p_tracep = NULL; 274 } 275 /* 276 * Set the new credentials. 277 */ 278 p->p_ucred = crcopy(p->p_ucred); 279 if (attr.va_mode & VSUID) 280 p->p_ucred->cr_uid = attr.va_uid; 281 if (attr.va_mode & VSGID) 282 p->p_ucred->cr_groups[0] = attr.va_gid; 283 p->p_flag |= P_SUGID; 284 } else { 285 p->p_flag &= ~P_SUGID; 286 } 287 288 /* 289 * Implement correct POSIX saved-id behavior. 290 */ 291 p->p_cred->p_svuid = p->p_ucred->cr_uid; 292 p->p_cred->p_svgid = p->p_ucred->cr_gid; 293 294 /* 295 * Store the vp for use in procfs 296 */ 297 if (p->p_textvp) /* release old reference */ 298 vrele(p->p_textvp); 299 VREF(ndp->ni_vp); 300 p->p_textvp = ndp->ni_vp; 301 302 /* 303 * If tracing the process, trap to debugger so breakpoints 304 * can be set before the program executes. 305 */ 306 if (p->p_flag & P_TRACED) 307 psignal(p, SIGTRAP); 308 309 /* clear "fork but no exec" flag, as we _are_ execing */ 310 p->p_acflag &= ~AFORK; 311 312 /* Set entry address */ 313 setregs(p, imgp->entry_addr, (u_long)stack_base); 314 315 /* 316 * free various allocated resources 317 */ 318 kmem_free(exec_map, (vm_offset_t)imgp->stringbase, ARG_MAX); 319 if (vm_map_remove(kernel_map, (vm_offset_t)imgp->image_header, 320 (vm_offset_t)imgp->image_header + PAGE_SIZE)) 321 panic("execve: header dealloc failed (2)"); 322 vrele(ndp->ni_vp); 323 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 324 325 return (0); 326 327exec_fail_dealloc: 328 if (imgp->stringbase != NULL) 329 kmem_free(exec_map, (vm_offset_t)imgp->stringbase, ARG_MAX); 330 if (imgp->image_header && imgp->image_header != (char *)-1) 331 if (vm_map_remove(kernel_map, (vm_offset_t)imgp->image_header, 332 (vm_offset_t)imgp->image_header + PAGE_SIZE)) 333 panic("execve: header dealloc failed (3)"); 334 if (ndp->ni_vp) 335 vrele(ndp->ni_vp); 336 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 337 338exec_fail: 339 if (imgp->vmspace_destroyed) { 340 /* sorry, no more process anymore. exit gracefully */ 341 exit1(p, W_EXITCODE(0, SIGABRT)); 342 /* NOT REACHED */ 343 return(0); 344 } else { 345 return(error); 346 } 347} 348 349/* 350 * Destroy old address space, and allocate a new stack 351 * The new stack is only SGROWSIZ large because it is grown 352 * automatically in trap.c. 353 */ 354int 355exec_new_vmspace(imgp) 356 struct image_params *imgp; 357{ 358 int error; 359 struct vmspace *vmspace = imgp->proc->p_vmspace; 360 caddr_t stack_addr = (caddr_t) (USRSTACK - SGROWSIZ); 361 362 imgp->vmspace_destroyed = 1; 363 364 /* Blow away entire process VM */ 365 if (vmspace->vm_shm) 366 shmexit(imgp->proc); 367 vm_map_remove(&vmspace->vm_map, 0, USRSTACK); 368 369 /* Allocate a new stack */ 370 error = vm_map_find(&vmspace->vm_map, NULL, 0, (vm_offset_t *)&stack_addr, 371 SGROWSIZ, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0); 372 if (error) 373 return(error); 374 375 vmspace->vm_ssize = SGROWSIZ >> PAGE_SHIFT; 376 377 /* Initialize maximum stack address */ 378 vmspace->vm_maxsaddr = (char *)USRSTACK - MAXSSIZ; 379 380 return(0); 381} 382 383/* 384 * Copy out argument and environment strings from the old process 385 * address space into the temporary string buffer. 386 */ 387int 388exec_extract_strings(imgp) 389 struct image_params *imgp; 390{ 391 char **argv, **envv; 392 char *argp, *envp; 393 int error, length; 394 395 /* 396 * extract arguments first 397 */ 398 399 argv = imgp->uap->argv; 400 401 if (argv) { 402 while ((argp = (caddr_t) fuword(argv++))) { 403 if (argp == (caddr_t) -1) 404 return (EFAULT); 405 if ((error = copyinstr(argp, imgp->stringp, 406 imgp->stringspace, &length))) { 407 if (error == ENAMETOOLONG) 408 return(E2BIG); 409 return (error); 410 } 411 imgp->stringspace -= length; 412 imgp->stringp += length; 413 imgp->argc++; 414 } 415 } 416 417 /* 418 * extract environment strings 419 */ 420 421 envv = imgp->uap->envv; 422 423 if (envv) { 424 while ((envp = (caddr_t) fuword(envv++))) { 425 if (envp == (caddr_t) -1) 426 return (EFAULT); 427 if ((error = copyinstr(envp, imgp->stringp, 428 imgp->stringspace, &length))) { 429 if (error == ENAMETOOLONG) 430 return(E2BIG); 431 return (error); 432 } 433 imgp->stringspace -= length; 434 imgp->stringp += length; 435 imgp->envc++; 436 } 437 } 438 439 return (0); 440} 441 442/* 443 * Copy strings out to the new process address space, constructing 444 * new arg and env vector tables. Return a pointer to the base 445 * so that it can be used as the initial stack pointer. 446 */ 447int * 448exec_copyout_strings(imgp) 449 struct image_params *imgp; 450{ 451 int argc, envc; 452 char **vectp; 453 char *stringp, *destp; 454 int *stack_base; 455 struct ps_strings *arginfo; 456 int szsigcode; 457 458 /* 459 * Calculate string base and vector table pointers. 460 * Also deal with signal trampoline code for this exec type. 461 */ 462 arginfo = PS_STRINGS; 463 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode); 464 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 465 roundup((ARG_MAX - imgp->stringspace), sizeof(char *)); 466 467 /* 468 * install sigcode 469 */ 470 if (szsigcode) 471 copyout(imgp->proc->p_sysent->sv_sigcode, 472 ((caddr_t)arginfo - szsigcode), szsigcode); 473 474 /* 475 * If we have a valid auxargs ptr, prepare some room 476 * on the stack. 477 */ 478 if (imgp->auxargs) 479 /* 480 * The '+ 2' is for the null pointers at the end of each of the 481 * arg and env vector sets, and 'AT_COUNT*2' is room for the 482 * ELF Auxargs data. 483 */ 484 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2 + 485 AT_COUNT*2) * sizeof(char*)); 486 else 487 /* 488 * The '+ 2' is for the null pointers at the end of each of the 489 * arg and env vector sets 490 */ 491 vectp = (char **) 492 (destp - (imgp->argc + imgp->envc + 2) * sizeof(char*)); 493 494 /* 495 * vectp also becomes our initial stack base 496 */ 497 stack_base = (int *)vectp; 498 499 stringp = imgp->stringbase; 500 argc = imgp->argc; 501 envc = imgp->envc; 502 503 /* 504 * Copy out strings - arguments and environment. 505 */ 506 copyout(stringp, destp, ARG_MAX - imgp->stringspace); 507 508 /* 509 * Fill in "ps_strings" struct for ps, w, etc. 510 */ 511 suword(&arginfo->ps_argvstr, (int)vectp); 512 suword(&arginfo->ps_nargvstr, argc); 513 514 /* 515 * Fill in argument portion of vector table. 516 */ 517 for (; argc > 0; --argc) { 518 suword(vectp++, (int)destp); 519 while (*stringp++ != 0) 520 destp++; 521 destp++; 522 } 523 524 /* a null vector table pointer seperates the argp's from the envp's */ 525 suword(vectp++, NULL); 526 527 suword(&arginfo->ps_envstr, (int)vectp); 528 suword(&arginfo->ps_nenvstr, envc); 529 530 /* 531 * Fill in environment portion of vector table. 532 */ 533 for (; envc > 0; --envc) { 534 suword(vectp++, (int)destp); 535 while (*stringp++ != 0) 536 destp++; 537 destp++; 538 } 539 540 /* end of vector table is a null pointer */ 541 suword(vectp, NULL); 542 543 return (stack_base); 544} 545 546/* 547 * Check permissions of file to execute. 548 * Return 0 for success or error code on failure. 549 */ 550static int 551exec_check_permissions(imgp) 552 struct image_params *imgp; 553{ 554 struct proc *p = imgp->proc; 555 struct vnode *vp = imgp->vp; 556 struct vattr *attr = imgp->attr; 557 int error; 558 559 /* 560 * Check number of open-for-writes on the file and deny execution 561 * if there are any. 562 */ 563 if (vp->v_writecount) { 564 return (ETXTBSY); 565 } 566 567 /* Get file attributes */ 568 error = VOP_GETATTR(vp, attr, p->p_ucred, p); 569 if (error) 570 return (error); 571 572 /* 573 * 1) Check if file execution is disabled for the filesystem that this 574 * file resides on. 575 * 2) Insure that at least one execute bit is on - otherwise root 576 * will always succeed, and we don't want to happen unless the 577 * file really is executable. 578 * 3) Insure that the file is a regular file. 579 */ 580 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 581 ((attr->va_mode & 0111) == 0) || 582 (attr->va_type != VREG)) { 583 return (EACCES); 584 } 585 586 /* 587 * Zero length files can't be exec'd 588 */ 589 if (attr->va_size == 0) 590 return (ENOEXEC); 591 592 /* 593 * Disable setuid/setgid if the filesystem prohibits it or if 594 * the process is being traced. 595 */ 596 if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED)) 597 attr->va_mode &= ~(VSUID | VSGID); 598 599 /* 600 * Check for execute permission to file based on current credentials. 601 * Then call filesystem specific open routine (which does nothing 602 * in the general case). 603 */ 604 error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p); 605 if (error) 606 return (error); 607 608 error = VOP_OPEN(vp, FREAD, p->p_ucred, p); 609 if (error) 610 return (error); 611 612 return (0); 613}
| 50 51#include <vm/vm.h> 52#include <vm/vm_param.h> 53#include <vm/vm_prot.h> 54#include <vm/lock.h> 55#include <vm/pmap.h> 56#include <vm/vm_map.h> 57#include <vm/vm_kern.h> 58#include <vm/vm_extern.h> 59 60#include <machine/reg.h> 61 62static int *exec_copyout_strings __P((struct image_params *)); 63 64static int exec_check_permissions(struct image_params *); 65 66/* 67 * XXX trouble here if sizeof(caddr_t) != sizeof(int), other parts 68 * of the sysctl code also assumes this, and sizeof(int) == sizeof(long). 69 */ 70static caddr_t ps_strings = (caddr_t)PS_STRINGS; 71SYSCTL_INT(_kern, KERN_PS_STRINGS, ps_strings, 0, &ps_strings, 0, ""); 72 73static caddr_t usrstack = (caddr_t)USRSTACK; 74SYSCTL_INT(_kern, KERN_USRSTACK, usrstack, 0, &usrstack, 0, ""); 75 76/* 77 * execsw_set is constructed for us by the linker. Each of the items 78 * is a pointer to a `const struct execsw', hence the double pointer here. 79 */ 80static const struct execsw **execsw = 81 (const struct execsw **)&execsw_set.ls_items[0]; 82 83#ifndef _SYS_SYSPROTO_H_ 84struct execve_args { 85 char *fname; 86 char **argv; 87 char **envv; 88}; 89#endif 90 91/* 92 * execve() system call. 93 */ 94int 95execve(p, uap, retval) 96 struct proc *p; 97 register struct execve_args *uap; 98 int *retval; 99{ 100 struct nameidata nd, *ndp; 101 int *stack_base; 102 int error, len, i; 103 struct image_params image_params, *imgp; 104 struct vattr attr; 105 106 imgp = &image_params; 107 108 /* 109 * Initialize part of the common data 110 */ 111 imgp->proc = p; 112 imgp->uap = uap; 113 imgp->attr = &attr; 114 imgp->image_header = NULL; 115 imgp->argc = imgp->envc = 0; 116 imgp->entry_addr = 0; 117 imgp->vmspace_destroyed = 0; 118 imgp->interpreted = 0; 119 imgp->interpreter_name[0] = '\0'; 120 imgp->auxargs = NULL; 121 122 /* 123 * Allocate temporary demand zeroed space for argument and 124 * environment strings 125 */ 126 imgp->stringbase = (char *)kmem_alloc_pageable(exec_map, ARG_MAX); 127 if (imgp->stringbase == NULL) { 128 error = ENOMEM; 129 goto exec_fail; 130 } 131 imgp->stringp = imgp->stringbase; 132 imgp->stringspace = ARG_MAX; 133 134 /* 135 * Translate the file name. namei() returns a vnode pointer 136 * in ni_vp amoung other things. 137 */ 138 ndp = &nd; 139 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 140 UIO_USERSPACE, uap->fname, p); 141 142interpret: 143 144 error = namei(ndp); 145 if (error) { 146 kmem_free(exec_map, (vm_offset_t)imgp->stringbase, ARG_MAX); 147 goto exec_fail; 148 } 149 150 imgp->vp = ndp->ni_vp; 151 if (imgp->vp == NULL) { 152 error = ENOEXEC; 153 goto exec_fail_dealloc; 154 } 155 156 /* 157 * Check file permissions (also 'opens' file) 158 */ 159 error = exec_check_permissions(imgp); 160 161 /* 162 * Lose the lock on the vnode. It's no longer needed, and must not 163 * exist for the pagefault paging to work below. 164 */ 165 VOP_UNLOCK(imgp->vp); 166 167 if (error) 168 goto exec_fail_dealloc; 169 170 /* 171 * Map the image header (first page) of the file into 172 * kernel address space 173 */ 174 error = vm_mmap(kernel_map, /* map */ 175 (vm_offset_t *)&imgp->image_header, /* address */ 176 PAGE_SIZE, /* size */ 177 VM_PROT_READ, /* protection */ 178 VM_PROT_READ, /* max protection */ 179 0, /* flags */ 180 (caddr_t)imgp->vp, /* vnode */ 181 0); /* offset */ 182 if (error) { 183 uprintf("mmap failed: %d\n",error); 184 goto exec_fail_dealloc; 185 } 186 187 /* 188 * Loop through list of image activators, calling each one. 189 * If there is no match, the activator returns -1. If there 190 * is a match, but there was an error during the activation, 191 * the error is returned. Otherwise 0 means success. If the 192 * image is interpreted, loop back up and try activating 193 * the interpreter. 194 */ 195 for (i = 0; execsw[i]; ++i) { 196 if (execsw[i]->ex_imgact) 197 error = (*execsw[i]->ex_imgact)(imgp); 198 else 199 continue; 200 201 if (error == -1) 202 continue; 203 if (error) 204 goto exec_fail_dealloc; 205 if (imgp->interpreted) { 206 /* free old vnode and name buffer */ 207 vrele(ndp->ni_vp); 208 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 209 if (vm_map_remove(kernel_map, (vm_offset_t)imgp->image_header, 210 (vm_offset_t)imgp->image_header + PAGE_SIZE)) 211 panic("execve: header dealloc failed (1)"); 212 213 /* set new name to that of the interpreter */ 214 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 215 UIO_SYSSPACE, imgp->interpreter_name, p); 216 goto interpret; 217 } 218 break; 219 } 220 /* If we made it through all the activators and none matched, exit. */ 221 if (error == -1) { 222 error = ENOEXEC; 223 goto exec_fail_dealloc; 224 } 225 226 /* 227 * Copy out strings (args and env) and initialize stack base 228 */ 229 stack_base = exec_copyout_strings(imgp); 230 p->p_vmspace->vm_minsaddr = (char *)stack_base; 231 232 /* 233 * If custom stack fixup routine present for this process 234 * let it do the stack setup. 235 * Else stuff argument count as first item on stack 236 */ 237 if (p->p_sysent->sv_fixup) 238 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 239 else 240 suword(--stack_base, imgp->argc); 241 242 /* close files on exec */ 243 fdcloseexec(p); 244 245 /* reset caught signals */ 246 execsigs(p); 247 248 /* name this process - nameiexec(p, ndp) */ 249 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 250 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 251 p->p_comm[len] = 0; 252 253 /* 254 * mark as execed, wakeup the process that vforked (if any) and tell 255 * it that it now has it's own resources back 256 */ 257 p->p_flag |= P_EXEC; 258 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 259 p->p_flag &= ~P_PPWAIT; 260 wakeup((caddr_t)p->p_pptr); 261 } 262 263 /* 264 * Implement image setuid/setgid. Disallow if the process is 265 * being traced. 266 */ 267 if ((attr.va_mode & (VSUID | VSGID)) && 268 (p->p_flag & P_TRACED) == 0) { 269 /* 270 * Turn off syscall tracing for set-id programs, except for 271 * root. 272 */ 273 if (p->p_tracep && suser(p->p_ucred, &p->p_acflag)) { 274 p->p_traceflag = 0; 275 vrele(p->p_tracep); 276 p->p_tracep = NULL; 277 } 278 /* 279 * Set the new credentials. 280 */ 281 p->p_ucred = crcopy(p->p_ucred); 282 if (attr.va_mode & VSUID) 283 p->p_ucred->cr_uid = attr.va_uid; 284 if (attr.va_mode & VSGID) 285 p->p_ucred->cr_groups[0] = attr.va_gid; 286 p->p_flag |= P_SUGID; 287 } else { 288 p->p_flag &= ~P_SUGID; 289 } 290 291 /* 292 * Implement correct POSIX saved-id behavior. 293 */ 294 p->p_cred->p_svuid = p->p_ucred->cr_uid; 295 p->p_cred->p_svgid = p->p_ucred->cr_gid; 296 297 /* 298 * Store the vp for use in procfs 299 */ 300 if (p->p_textvp) /* release old reference */ 301 vrele(p->p_textvp); 302 VREF(ndp->ni_vp); 303 p->p_textvp = ndp->ni_vp; 304 305 /* 306 * If tracing the process, trap to debugger so breakpoints 307 * can be set before the program executes. 308 */ 309 if (p->p_flag & P_TRACED) 310 psignal(p, SIGTRAP); 311 312 /* clear "fork but no exec" flag, as we _are_ execing */ 313 p->p_acflag &= ~AFORK; 314 315 /* Set entry address */ 316 setregs(p, imgp->entry_addr, (u_long)stack_base); 317 318 /* 319 * free various allocated resources 320 */ 321 kmem_free(exec_map, (vm_offset_t)imgp->stringbase, ARG_MAX); 322 if (vm_map_remove(kernel_map, (vm_offset_t)imgp->image_header, 323 (vm_offset_t)imgp->image_header + PAGE_SIZE)) 324 panic("execve: header dealloc failed (2)"); 325 vrele(ndp->ni_vp); 326 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 327 328 return (0); 329 330exec_fail_dealloc: 331 if (imgp->stringbase != NULL) 332 kmem_free(exec_map, (vm_offset_t)imgp->stringbase, ARG_MAX); 333 if (imgp->image_header && imgp->image_header != (char *)-1) 334 if (vm_map_remove(kernel_map, (vm_offset_t)imgp->image_header, 335 (vm_offset_t)imgp->image_header + PAGE_SIZE)) 336 panic("execve: header dealloc failed (3)"); 337 if (ndp->ni_vp) 338 vrele(ndp->ni_vp); 339 FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI); 340 341exec_fail: 342 if (imgp->vmspace_destroyed) { 343 /* sorry, no more process anymore. exit gracefully */ 344 exit1(p, W_EXITCODE(0, SIGABRT)); 345 /* NOT REACHED */ 346 return(0); 347 } else { 348 return(error); 349 } 350} 351 352/* 353 * Destroy old address space, and allocate a new stack 354 * The new stack is only SGROWSIZ large because it is grown 355 * automatically in trap.c. 356 */ 357int 358exec_new_vmspace(imgp) 359 struct image_params *imgp; 360{ 361 int error; 362 struct vmspace *vmspace = imgp->proc->p_vmspace; 363 caddr_t stack_addr = (caddr_t) (USRSTACK - SGROWSIZ); 364 365 imgp->vmspace_destroyed = 1; 366 367 /* Blow away entire process VM */ 368 if (vmspace->vm_shm) 369 shmexit(imgp->proc); 370 vm_map_remove(&vmspace->vm_map, 0, USRSTACK); 371 372 /* Allocate a new stack */ 373 error = vm_map_find(&vmspace->vm_map, NULL, 0, (vm_offset_t *)&stack_addr, 374 SGROWSIZ, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0); 375 if (error) 376 return(error); 377 378 vmspace->vm_ssize = SGROWSIZ >> PAGE_SHIFT; 379 380 /* Initialize maximum stack address */ 381 vmspace->vm_maxsaddr = (char *)USRSTACK - MAXSSIZ; 382 383 return(0); 384} 385 386/* 387 * Copy out argument and environment strings from the old process 388 * address space into the temporary string buffer. 389 */ 390int 391exec_extract_strings(imgp) 392 struct image_params *imgp; 393{ 394 char **argv, **envv; 395 char *argp, *envp; 396 int error, length; 397 398 /* 399 * extract arguments first 400 */ 401 402 argv = imgp->uap->argv; 403 404 if (argv) { 405 while ((argp = (caddr_t) fuword(argv++))) { 406 if (argp == (caddr_t) -1) 407 return (EFAULT); 408 if ((error = copyinstr(argp, imgp->stringp, 409 imgp->stringspace, &length))) { 410 if (error == ENAMETOOLONG) 411 return(E2BIG); 412 return (error); 413 } 414 imgp->stringspace -= length; 415 imgp->stringp += length; 416 imgp->argc++; 417 } 418 } 419 420 /* 421 * extract environment strings 422 */ 423 424 envv = imgp->uap->envv; 425 426 if (envv) { 427 while ((envp = (caddr_t) fuword(envv++))) { 428 if (envp == (caddr_t) -1) 429 return (EFAULT); 430 if ((error = copyinstr(envp, imgp->stringp, 431 imgp->stringspace, &length))) { 432 if (error == ENAMETOOLONG) 433 return(E2BIG); 434 return (error); 435 } 436 imgp->stringspace -= length; 437 imgp->stringp += length; 438 imgp->envc++; 439 } 440 } 441 442 return (0); 443} 444 445/* 446 * Copy strings out to the new process address space, constructing 447 * new arg and env vector tables. Return a pointer to the base 448 * so that it can be used as the initial stack pointer. 449 */ 450int * 451exec_copyout_strings(imgp) 452 struct image_params *imgp; 453{ 454 int argc, envc; 455 char **vectp; 456 char *stringp, *destp; 457 int *stack_base; 458 struct ps_strings *arginfo; 459 int szsigcode; 460 461 /* 462 * Calculate string base and vector table pointers. 463 * Also deal with signal trampoline code for this exec type. 464 */ 465 arginfo = PS_STRINGS; 466 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode); 467 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 468 roundup((ARG_MAX - imgp->stringspace), sizeof(char *)); 469 470 /* 471 * install sigcode 472 */ 473 if (szsigcode) 474 copyout(imgp->proc->p_sysent->sv_sigcode, 475 ((caddr_t)arginfo - szsigcode), szsigcode); 476 477 /* 478 * If we have a valid auxargs ptr, prepare some room 479 * on the stack. 480 */ 481 if (imgp->auxargs) 482 /* 483 * The '+ 2' is for the null pointers at the end of each of the 484 * arg and env vector sets, and 'AT_COUNT*2' is room for the 485 * ELF Auxargs data. 486 */ 487 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2 + 488 AT_COUNT*2) * sizeof(char*)); 489 else 490 /* 491 * The '+ 2' is for the null pointers at the end of each of the 492 * arg and env vector sets 493 */ 494 vectp = (char **) 495 (destp - (imgp->argc + imgp->envc + 2) * sizeof(char*)); 496 497 /* 498 * vectp also becomes our initial stack base 499 */ 500 stack_base = (int *)vectp; 501 502 stringp = imgp->stringbase; 503 argc = imgp->argc; 504 envc = imgp->envc; 505 506 /* 507 * Copy out strings - arguments and environment. 508 */ 509 copyout(stringp, destp, ARG_MAX - imgp->stringspace); 510 511 /* 512 * Fill in "ps_strings" struct for ps, w, etc. 513 */ 514 suword(&arginfo->ps_argvstr, (int)vectp); 515 suword(&arginfo->ps_nargvstr, argc); 516 517 /* 518 * Fill in argument portion of vector table. 519 */ 520 for (; argc > 0; --argc) { 521 suword(vectp++, (int)destp); 522 while (*stringp++ != 0) 523 destp++; 524 destp++; 525 } 526 527 /* a null vector table pointer seperates the argp's from the envp's */ 528 suword(vectp++, NULL); 529 530 suword(&arginfo->ps_envstr, (int)vectp); 531 suword(&arginfo->ps_nenvstr, envc); 532 533 /* 534 * Fill in environment portion of vector table. 535 */ 536 for (; envc > 0; --envc) { 537 suword(vectp++, (int)destp); 538 while (*stringp++ != 0) 539 destp++; 540 destp++; 541 } 542 543 /* end of vector table is a null pointer */ 544 suword(vectp, NULL); 545 546 return (stack_base); 547} 548 549/* 550 * Check permissions of file to execute. 551 * Return 0 for success or error code on failure. 552 */ 553static int 554exec_check_permissions(imgp) 555 struct image_params *imgp; 556{ 557 struct proc *p = imgp->proc; 558 struct vnode *vp = imgp->vp; 559 struct vattr *attr = imgp->attr; 560 int error; 561 562 /* 563 * Check number of open-for-writes on the file and deny execution 564 * if there are any. 565 */ 566 if (vp->v_writecount) { 567 return (ETXTBSY); 568 } 569 570 /* Get file attributes */ 571 error = VOP_GETATTR(vp, attr, p->p_ucred, p); 572 if (error) 573 return (error); 574 575 /* 576 * 1) Check if file execution is disabled for the filesystem that this 577 * file resides on. 578 * 2) Insure that at least one execute bit is on - otherwise root 579 * will always succeed, and we don't want to happen unless the 580 * file really is executable. 581 * 3) Insure that the file is a regular file. 582 */ 583 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 584 ((attr->va_mode & 0111) == 0) || 585 (attr->va_type != VREG)) { 586 return (EACCES); 587 } 588 589 /* 590 * Zero length files can't be exec'd 591 */ 592 if (attr->va_size == 0) 593 return (ENOEXEC); 594 595 /* 596 * Disable setuid/setgid if the filesystem prohibits it or if 597 * the process is being traced. 598 */ 599 if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED)) 600 attr->va_mode &= ~(VSUID | VSGID); 601 602 /* 603 * Check for execute permission to file based on current credentials. 604 * Then call filesystem specific open routine (which does nothing 605 * in the general case). 606 */ 607 error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p); 608 if (error) 609 return (error); 610 611 error = VOP_OPEN(vp, FREAD, p->p_ucred, p); 612 if (error) 613 return (error); 614 615 return (0); 616}
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