1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1994-1996 Søren Schmidt 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 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/exec.h> 35 #include <sys/fcntl.h> 36 #include <sys/imgact.h> 37 #include <sys/imgact_aout.h> 38 #include <sys/imgact_elf.h> 39 #include <sys/kernel.h> 40 #include <sys/lock.h> 41 #include <sys/malloc.h> 42 #include <sys/module.h> 43 #include <sys/mutex.h> 44 #include <sys/proc.h> 45 #include <sys/signalvar.h> 46 #include <sys/syscallsubr.h> 47 #include <sys/sysctl.h> 48 #include <sys/sysent.h> 49 #include <sys/sysproto.h> 50 #include <sys/vnode.h> 51 #include <sys/eventhandler.h> 52 53 #include <vm/vm.h> 54 #include <vm/pmap.h> 55 #include <vm/vm_extern.h> 56 #include <vm/vm_map.h> 57 #include <vm/vm_object.h> 58 #include <vm/vm_page.h> 59 #include <vm/vm_param.h> 60 61 #include <machine/cpu.h> 62 #include <machine/cputypes.h> 63 #include <machine/md_var.h> 64 #include <machine/pcb.h> 65 #include <machine/trap.h> 66 67 #include <i386/linux/linux.h> 68 #include <i386/linux/linux_proto.h> 69 #include <compat/linux/linux_emul.h> 70 #include <compat/linux/linux_futex.h> 71 #include <compat/linux/linux_ioctl.h> 72 #include <compat/linux/linux_mib.h> 73 #include <compat/linux/linux_misc.h> 74 #include <compat/linux/linux_signal.h> 75 #include <compat/linux/linux_util.h> 76 #include <compat/linux/linux_vdso.h> 77 78 MODULE_VERSION(linux, 1); 79 80 #if defined(DEBUG) 81 SYSCTL_PROC(_compat_linux, OID_AUTO, debug, CTLTYPE_STRING | CTLFLAG_RW, 0, 0, 82 linux_sysctl_debug, "A", "Linux debugging control"); 83 #endif 84 85 /* 86 * Allow the sendsig functions to use the ldebug() facility even though they 87 * are not syscalls themselves. Map them to syscall 0. This is slightly less 88 * bogus than using ldebug(sigreturn). 89 */ 90 #define LINUX_SYS_linux_rt_sendsig 0 91 #define LINUX_SYS_linux_sendsig 0 92 93 #define LINUX_PS_STRINGS (LINUX_USRSTACK - sizeof(struct ps_strings)) 94 95 static int linux_szsigcode; 96 static vm_object_t linux_shared_page_obj; 97 static char *linux_shared_page_mapping; 98 extern char _binary_linux_locore_o_start; 99 extern char _binary_linux_locore_o_end; 100 101 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL]; 102 103 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler); 104 105 static int linux_fixup(register_t **stack_base, 106 struct image_params *iparams); 107 static int linux_fixup_elf(register_t **stack_base, 108 struct image_params *iparams); 109 static void linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask); 110 static void linux_exec_setregs(struct thread *td, 111 struct image_params *imgp, u_long stack); 112 static register_t *linux_copyout_strings(struct image_params *imgp); 113 static bool linux_trans_osrel(const Elf_Note *note, int32_t *osrel); 114 static void linux_vdso_install(void *param); 115 static void linux_vdso_deinstall(void *param); 116 117 static int linux_szplatform; 118 const char *linux_kplatform; 119 120 static eventhandler_tag linux_exit_tag; 121 static eventhandler_tag linux_exec_tag; 122 static eventhandler_tag linux_thread_dtor_tag; 123 124 #define LINUX_T_UNKNOWN 255 125 static int _bsd_to_linux_trapcode[] = { 126 LINUX_T_UNKNOWN, /* 0 */ 127 6, /* 1 T_PRIVINFLT */ 128 LINUX_T_UNKNOWN, /* 2 */ 129 3, /* 3 T_BPTFLT */ 130 LINUX_T_UNKNOWN, /* 4 */ 131 LINUX_T_UNKNOWN, /* 5 */ 132 16, /* 6 T_ARITHTRAP */ 133 254, /* 7 T_ASTFLT */ 134 LINUX_T_UNKNOWN, /* 8 */ 135 13, /* 9 T_PROTFLT */ 136 1, /* 10 T_TRCTRAP */ 137 LINUX_T_UNKNOWN, /* 11 */ 138 14, /* 12 T_PAGEFLT */ 139 LINUX_T_UNKNOWN, /* 13 */ 140 17, /* 14 T_ALIGNFLT */ 141 LINUX_T_UNKNOWN, /* 15 */ 142 LINUX_T_UNKNOWN, /* 16 */ 143 LINUX_T_UNKNOWN, /* 17 */ 144 0, /* 18 T_DIVIDE */ 145 2, /* 19 T_NMI */ 146 4, /* 20 T_OFLOW */ 147 5, /* 21 T_BOUND */ 148 7, /* 22 T_DNA */ 149 8, /* 23 T_DOUBLEFLT */ 150 9, /* 24 T_FPOPFLT */ 151 10, /* 25 T_TSSFLT */ 152 11, /* 26 T_SEGNPFLT */ 153 12, /* 27 T_STKFLT */ 154 18, /* 28 T_MCHK */ 155 19, /* 29 T_XMMFLT */ 156 15 /* 30 T_RESERVED */ 157 }; 158 #define bsd_to_linux_trapcode(code) \ 159 ((code)<nitems(_bsd_to_linux_trapcode)? \ 160 _bsd_to_linux_trapcode[(code)]: \ 161 LINUX_T_UNKNOWN) 162 163 LINUX_VDSO_SYM_INTPTR(linux_sigcode); 164 LINUX_VDSO_SYM_INTPTR(linux_rt_sigcode); 165 LINUX_VDSO_SYM_INTPTR(linux_vsyscall); 166 167 /* 168 * If FreeBSD & Linux have a difference of opinion about what a trap 169 * means, deal with it here. 170 * 171 * MPSAFE 172 */ 173 static int 174 linux_translate_traps(int signal, int trap_code) 175 { 176 if (signal != SIGBUS) 177 return (signal); 178 switch (trap_code) { 179 case T_PROTFLT: 180 case T_TSSFLT: 181 case T_DOUBLEFLT: 182 case T_PAGEFLT: 183 return (SIGSEGV); 184 default: 185 return (signal); 186 } 187 } 188 189 static int 190 linux_fixup(register_t **stack_base, struct image_params *imgp) 191 { 192 register_t *argv, *envp; 193 194 argv = *stack_base; 195 envp = *stack_base + (imgp->args->argc + 1); 196 (*stack_base)--; 197 suword(*stack_base, (intptr_t)(void *)envp); 198 (*stack_base)--; 199 suword(*stack_base, (intptr_t)(void *)argv); 200 (*stack_base)--; 201 suword(*stack_base, imgp->args->argc); 202 return (0); 203 } 204 205 static int 206 linux_fixup_elf(register_t **stack_base, struct image_params *imgp) 207 { 208 struct proc *p; 209 Elf32_Auxargs *args; 210 Elf32_Auxinfo *argarray, *pos; 211 Elf32_Addr *auxbase, *uplatform; 212 struct ps_strings *arginfo; 213 int error, issetugid; 214 215 KASSERT(curthread->td_proc == imgp->proc, 216 ("unsafe linux_fixup_elf(), should be curproc")); 217 218 p = imgp->proc; 219 issetugid = imgp->proc->p_flag & P_SUGID ? 1 : 0; 220 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 221 uplatform = (Elf32_Addr *)((caddr_t)arginfo - linux_szplatform); 222 args = (Elf32_Auxargs *)imgp->auxargs; 223 auxbase = *stack_base + imgp->args->argc + 1 + imgp->args->envc + 1; 224 argarray = pos = malloc(LINUX_AT_COUNT * sizeof(*pos), M_TEMP, 225 M_WAITOK | M_ZERO); 226 227 AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO_EHDR, 228 imgp->proc->p_sysent->sv_shared_page_base); 229 AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO, linux_vsyscall); 230 AUXARGS_ENTRY(pos, LINUX_AT_HWCAP, cpu_feature); 231 232 /* 233 * Do not export AT_CLKTCK when emulating Linux kernel prior to 2.4.0, 234 * as it has appeared in the 2.4.0-rc7 first time. 235 * Being exported, AT_CLKTCK is returned by sysconf(_SC_CLK_TCK), 236 * glibc falls back to the hard-coded CLK_TCK value when aux entry 237 * is not present. 238 * Also see linux_times() implementation. 239 */ 240 if (linux_kernver(curthread) >= LINUX_KERNVER_2004000) 241 AUXARGS_ENTRY(pos, LINUX_AT_CLKTCK, stclohz); 242 AUXARGS_ENTRY(pos, AT_PHDR, args->phdr); 243 AUXARGS_ENTRY(pos, AT_PHENT, args->phent); 244 AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum); 245 AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz); 246 AUXARGS_ENTRY(pos, AT_FLAGS, args->flags); 247 AUXARGS_ENTRY(pos, AT_ENTRY, args->entry); 248 AUXARGS_ENTRY(pos, AT_BASE, args->base); 249 AUXARGS_ENTRY(pos, LINUX_AT_SECURE, issetugid); 250 AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid); 251 AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid); 252 AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid); 253 AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid); 254 AUXARGS_ENTRY(pos, LINUX_AT_PLATFORM, PTROUT(uplatform)); 255 AUXARGS_ENTRY(pos, LINUX_AT_RANDOM, imgp->canary); 256 if (imgp->execpathp != 0) 257 AUXARGS_ENTRY(pos, LINUX_AT_EXECFN, imgp->execpathp); 258 if (args->execfd != -1) 259 AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd); 260 AUXARGS_ENTRY(pos, AT_NULL, 0); 261 262 free(imgp->auxargs, M_TEMP); 263 imgp->auxargs = NULL; 264 KASSERT(pos - argarray <= LINUX_AT_COUNT, ("Too many auxargs")); 265 266 error = copyout(argarray, auxbase, sizeof(*argarray) * LINUX_AT_COUNT); 267 free(argarray, M_TEMP); 268 if (error != 0) 269 return (error); 270 271 (*stack_base)--; 272 if (suword(*stack_base, (register_t)imgp->args->argc) == -1) 273 return (EFAULT); 274 return (0); 275 } 276 277 /* 278 * Copied from kern/kern_exec.c 279 */ 280 static register_t * 281 linux_copyout_strings(struct image_params *imgp) 282 { 283 int argc, envc; 284 char **vectp; 285 char *stringp, *destp; 286 register_t *stack_base; 287 struct ps_strings *arginfo; 288 char canary[LINUX_AT_RANDOM_LEN]; 289 size_t execpath_len; 290 struct proc *p; 291 292 /* Calculate string base and vector table pointers. */ 293 p = imgp->proc; 294 if (imgp->execpath != NULL && imgp->auxargs != NULL) 295 execpath_len = strlen(imgp->execpath) + 1; 296 else 297 execpath_len = 0; 298 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; 299 destp = (caddr_t)arginfo - SPARE_USRSPACE - linux_szplatform - 300 roundup(sizeof(canary), sizeof(char *)) - 301 roundup(execpath_len, sizeof(char *)) - 302 roundup(ARG_MAX - imgp->args->stringspace, sizeof(char *)); 303 304 /* Install LINUX_PLATFORM. */ 305 copyout(linux_kplatform, ((caddr_t)arginfo - linux_szplatform), 306 linux_szplatform); 307 308 if (execpath_len != 0) { 309 imgp->execpathp = (uintptr_t)arginfo - 310 linux_szplatform - execpath_len; 311 copyout(imgp->execpath, (void *)imgp->execpathp, execpath_len); 312 } 313 314 /* Prepare the canary for SSP. */ 315 arc4rand(canary, sizeof(canary), 0); 316 imgp->canary = (uintptr_t)arginfo - linux_szplatform - 317 roundup(execpath_len, sizeof(char *)) - 318 roundup(sizeof(canary), sizeof(char *)); 319 copyout(canary, (void *)imgp->canary, sizeof(canary)); 320 321 vectp = (char **)destp; 322 if (imgp->auxargs) { 323 /* 324 * Allocate room on the stack for the ELF auxargs 325 * array. It has LINUX_AT_COUNT entries. 326 */ 327 vectp -= howmany(LINUX_AT_COUNT * sizeof(Elf32_Auxinfo), 328 sizeof(*vectp)); 329 } 330 331 /* 332 * Allocate room for the argv[] and env vectors including the 333 * terminating NULL pointers. 334 */ 335 vectp -= imgp->args->argc + 1 + imgp->args->envc + 1; 336 337 /* vectp also becomes our initial stack base. */ 338 stack_base = (register_t *)vectp; 339 340 stringp = imgp->args->begin_argv; 341 argc = imgp->args->argc; 342 envc = imgp->args->envc; 343 344 /* Copy out strings - arguments and environment. */ 345 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace); 346 347 /* Fill in "ps_strings" struct for ps, w, etc. */ 348 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 349 suword(&arginfo->ps_nargvstr, argc); 350 351 /* Fill in argument portion of vector table. */ 352 for (; argc > 0; --argc) { 353 suword(vectp++, (long)(intptr_t)destp); 354 while (*stringp++ != 0) 355 destp++; 356 destp++; 357 } 358 359 /* A null vector table pointer separates the argp's from the envp's. */ 360 suword(vectp++, 0); 361 362 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 363 suword(&arginfo->ps_nenvstr, envc); 364 365 /* Fill in environment portion of vector table. */ 366 for (; envc > 0; --envc) { 367 suword(vectp++, (long)(intptr_t)destp); 368 while (*stringp++ != 0) 369 destp++; 370 destp++; 371 } 372 373 /* The end of the vector table is a null pointer. */ 374 suword(vectp, 0); 375 376 return (stack_base); 377 } 378 379 static void 380 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 381 { 382 struct thread *td = curthread; 383 struct proc *p = td->td_proc; 384 struct sigacts *psp; 385 struct trapframe *regs; 386 struct l_rt_sigframe *fp, frame; 387 int sig, code; 388 int oonstack; 389 390 sig = ksi->ksi_signo; 391 code = ksi->ksi_code; 392 PROC_LOCK_ASSERT(p, MA_OWNED); 393 psp = p->p_sigacts; 394 mtx_assert(&psp->ps_mtx, MA_OWNED); 395 regs = td->td_frame; 396 oonstack = sigonstack(regs->tf_esp); 397 398 #ifdef DEBUG 399 if (ldebug(rt_sendsig)) 400 printf(ARGS(rt_sendsig, "%p, %d, %p, %u"), 401 catcher, sig, (void*)mask, code); 402 #endif 403 /* Allocate space for the signal handler context. */ 404 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack && 405 SIGISMEMBER(psp->ps_sigonstack, sig)) { 406 fp = (struct l_rt_sigframe *)((uintptr_t)td->td_sigstk.ss_sp + 407 td->td_sigstk.ss_size - sizeof(struct l_rt_sigframe)); 408 } else 409 fp = (struct l_rt_sigframe *)regs->tf_esp - 1; 410 mtx_unlock(&psp->ps_mtx); 411 412 /* Build the argument list for the signal handler. */ 413 sig = bsd_to_linux_signal(sig); 414 415 bzero(&frame, sizeof(frame)); 416 417 frame.sf_handler = catcher; 418 frame.sf_sig = sig; 419 frame.sf_siginfo = &fp->sf_si; 420 frame.sf_ucontext = &fp->sf_sc; 421 422 /* Fill in POSIX parts. */ 423 ksiginfo_to_lsiginfo(ksi, &frame.sf_si, sig); 424 425 /* Build the signal context to be used by sigreturn. */ 426 frame.sf_sc.uc_flags = 0; /* XXX ??? */ 427 frame.sf_sc.uc_link = NULL; /* XXX ??? */ 428 429 frame.sf_sc.uc_stack.ss_sp = td->td_sigstk.ss_sp; 430 frame.sf_sc.uc_stack.ss_size = td->td_sigstk.ss_size; 431 frame.sf_sc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) 432 ? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE; 433 PROC_UNLOCK(p); 434 435 bsd_to_linux_sigset(mask, &frame.sf_sc.uc_sigmask); 436 437 frame.sf_sc.uc_mcontext.sc_mask = frame.sf_sc.uc_sigmask.__mask; 438 frame.sf_sc.uc_mcontext.sc_gs = rgs(); 439 frame.sf_sc.uc_mcontext.sc_fs = regs->tf_fs; 440 frame.sf_sc.uc_mcontext.sc_es = regs->tf_es; 441 frame.sf_sc.uc_mcontext.sc_ds = regs->tf_ds; 442 frame.sf_sc.uc_mcontext.sc_edi = regs->tf_edi; 443 frame.sf_sc.uc_mcontext.sc_esi = regs->tf_esi; 444 frame.sf_sc.uc_mcontext.sc_ebp = regs->tf_ebp; 445 frame.sf_sc.uc_mcontext.sc_ebx = regs->tf_ebx; 446 frame.sf_sc.uc_mcontext.sc_esp = regs->tf_esp; 447 frame.sf_sc.uc_mcontext.sc_edx = regs->tf_edx; 448 frame.sf_sc.uc_mcontext.sc_ecx = regs->tf_ecx; 449 frame.sf_sc.uc_mcontext.sc_eax = regs->tf_eax; 450 frame.sf_sc.uc_mcontext.sc_eip = regs->tf_eip; 451 frame.sf_sc.uc_mcontext.sc_cs = regs->tf_cs; 452 frame.sf_sc.uc_mcontext.sc_eflags = regs->tf_eflags; 453 frame.sf_sc.uc_mcontext.sc_esp_at_signal = regs->tf_esp; 454 frame.sf_sc.uc_mcontext.sc_ss = regs->tf_ss; 455 frame.sf_sc.uc_mcontext.sc_err = regs->tf_err; 456 frame.sf_sc.uc_mcontext.sc_cr2 = (register_t)ksi->ksi_addr; 457 frame.sf_sc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code); 458 459 #ifdef DEBUG 460 if (ldebug(rt_sendsig)) 461 printf(LMSG("rt_sendsig flags: 0x%x, sp: %p, ss: 0x%x, mask: 0x%x"), 462 frame.sf_sc.uc_stack.ss_flags, td->td_sigstk.ss_sp, 463 td->td_sigstk.ss_size, frame.sf_sc.uc_mcontext.sc_mask); 464 #endif 465 466 if (copyout(&frame, fp, sizeof(frame)) != 0) { 467 /* 468 * Process has trashed its stack; give it an illegal 469 * instruction to halt it in its tracks. 470 */ 471 #ifdef DEBUG 472 if (ldebug(rt_sendsig)) 473 printf(LMSG("rt_sendsig: bad stack %p, oonstack=%x"), 474 fp, oonstack); 475 #endif 476 PROC_LOCK(p); 477 sigexit(td, SIGILL); 478 } 479 480 /* Build context to run handler in. */ 481 regs->tf_esp = (int)fp; 482 regs->tf_eip = linux_rt_sigcode; 483 regs->tf_eflags &= ~(PSL_T | PSL_VM | PSL_D); 484 regs->tf_cs = _ucodesel; 485 regs->tf_ds = _udatasel; 486 regs->tf_es = _udatasel; 487 regs->tf_fs = _udatasel; 488 regs->tf_ss = _udatasel; 489 PROC_LOCK(p); 490 mtx_lock(&psp->ps_mtx); 491 } 492 493 494 /* 495 * Send an interrupt to process. 496 * 497 * Stack is set up to allow sigcode stored 498 * in u. to call routine, followed by kcall 499 * to sigreturn routine below. After sigreturn 500 * resets the signal mask, the stack, and the 501 * frame pointer, it returns to the user 502 * specified pc, psl. 503 */ 504 static void 505 linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 506 { 507 struct thread *td = curthread; 508 struct proc *p = td->td_proc; 509 struct sigacts *psp; 510 struct trapframe *regs; 511 struct l_sigframe *fp, frame; 512 l_sigset_t lmask; 513 int sig, code; 514 int oonstack; 515 516 PROC_LOCK_ASSERT(p, MA_OWNED); 517 psp = p->p_sigacts; 518 sig = ksi->ksi_signo; 519 code = ksi->ksi_code; 520 mtx_assert(&psp->ps_mtx, MA_OWNED); 521 if (SIGISMEMBER(psp->ps_siginfo, sig)) { 522 /* Signal handler installed with SA_SIGINFO. */ 523 linux_rt_sendsig(catcher, ksi, mask); 524 return; 525 } 526 regs = td->td_frame; 527 oonstack = sigonstack(regs->tf_esp); 528 529 #ifdef DEBUG 530 if (ldebug(sendsig)) 531 printf(ARGS(sendsig, "%p, %d, %p, %u"), 532 catcher, sig, (void*)mask, code); 533 #endif 534 535 /* Allocate space for the signal handler context. */ 536 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack && 537 SIGISMEMBER(psp->ps_sigonstack, sig)) { 538 fp = (struct l_sigframe *)((uintptr_t)td->td_sigstk.ss_sp + 539 td->td_sigstk.ss_size - sizeof(struct l_sigframe)); 540 } else 541 fp = (struct l_sigframe *)regs->tf_esp - 1; 542 mtx_unlock(&psp->ps_mtx); 543 PROC_UNLOCK(p); 544 545 /* Build the argument list for the signal handler. */ 546 sig = bsd_to_linux_signal(sig); 547 548 bzero(&frame, sizeof(frame)); 549 550 frame.sf_handler = catcher; 551 frame.sf_sig = sig; 552 553 bsd_to_linux_sigset(mask, &lmask); 554 555 /* Build the signal context to be used by sigreturn. */ 556 frame.sf_sc.sc_mask = lmask.__mask; 557 frame.sf_sc.sc_gs = rgs(); 558 frame.sf_sc.sc_fs = regs->tf_fs; 559 frame.sf_sc.sc_es = regs->tf_es; 560 frame.sf_sc.sc_ds = regs->tf_ds; 561 frame.sf_sc.sc_edi = regs->tf_edi; 562 frame.sf_sc.sc_esi = regs->tf_esi; 563 frame.sf_sc.sc_ebp = regs->tf_ebp; 564 frame.sf_sc.sc_ebx = regs->tf_ebx; 565 frame.sf_sc.sc_esp = regs->tf_esp; 566 frame.sf_sc.sc_edx = regs->tf_edx; 567 frame.sf_sc.sc_ecx = regs->tf_ecx; 568 frame.sf_sc.sc_eax = regs->tf_eax; 569 frame.sf_sc.sc_eip = regs->tf_eip; 570 frame.sf_sc.sc_cs = regs->tf_cs; 571 frame.sf_sc.sc_eflags = regs->tf_eflags; 572 frame.sf_sc.sc_esp_at_signal = regs->tf_esp; 573 frame.sf_sc.sc_ss = regs->tf_ss; 574 frame.sf_sc.sc_err = regs->tf_err; 575 frame.sf_sc.sc_cr2 = (register_t)ksi->ksi_addr; 576 frame.sf_sc.sc_trapno = bsd_to_linux_trapcode(ksi->ksi_trapno); 577 578 frame.sf_extramask[0] = lmask.__mask; 579 580 if (copyout(&frame, fp, sizeof(frame)) != 0) { 581 /* 582 * Process has trashed its stack; give it an illegal 583 * instruction to halt it in its tracks. 584 */ 585 PROC_LOCK(p); 586 sigexit(td, SIGILL); 587 } 588 589 /* Build context to run handler in. */ 590 regs->tf_esp = (int)fp; 591 regs->tf_eip = linux_sigcode; 592 regs->tf_eflags &= ~(PSL_T | PSL_VM | PSL_D); 593 regs->tf_cs = _ucodesel; 594 regs->tf_ds = _udatasel; 595 regs->tf_es = _udatasel; 596 regs->tf_fs = _udatasel; 597 regs->tf_ss = _udatasel; 598 PROC_LOCK(p); 599 mtx_lock(&psp->ps_mtx); 600 } 601 602 /* 603 * System call to cleanup state after a signal 604 * has been taken. Reset signal mask and 605 * stack state from context left by sendsig (above). 606 * Return to previous pc and psl as specified by 607 * context left by sendsig. Check carefully to 608 * make sure that the user has not modified the 609 * psl to gain improper privileges or to cause 610 * a machine fault. 611 */ 612 int 613 linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args) 614 { 615 struct l_sigframe frame; 616 struct trapframe *regs; 617 l_sigset_t lmask; 618 sigset_t bmask; 619 int eflags; 620 ksiginfo_t ksi; 621 622 regs = td->td_frame; 623 624 #ifdef DEBUG 625 if (ldebug(sigreturn)) 626 printf(ARGS(sigreturn, "%p"), (void *)args->sfp); 627 #endif 628 /* 629 * The trampoline code hands us the sigframe. 630 * It is unsafe to keep track of it ourselves, in the event that a 631 * program jumps out of a signal handler. 632 */ 633 if (copyin(args->sfp, &frame, sizeof(frame)) != 0) 634 return (EFAULT); 635 636 /* Check for security violations. */ 637 #define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) 638 eflags = frame.sf_sc.sc_eflags; 639 if (!EFLAGS_SECURE(eflags, regs->tf_eflags)) 640 return (EINVAL); 641 642 /* 643 * Don't allow users to load a valid privileged %cs. Let the 644 * hardware check for invalid selectors, excess privilege in 645 * other selectors, invalid %eip's and invalid %esp's. 646 */ 647 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) 648 if (!CS_SECURE(frame.sf_sc.sc_cs)) { 649 ksiginfo_init_trap(&ksi); 650 ksi.ksi_signo = SIGBUS; 651 ksi.ksi_code = BUS_OBJERR; 652 ksi.ksi_trapno = T_PROTFLT; 653 ksi.ksi_addr = (void *)regs->tf_eip; 654 trapsignal(td, &ksi); 655 return (EINVAL); 656 } 657 658 lmask.__mask = frame.sf_sc.sc_mask; 659 linux_to_bsd_sigset(&lmask, &bmask); 660 kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0); 661 662 /* Restore signal context. */ 663 /* %gs was restored by the trampoline. */ 664 regs->tf_fs = frame.sf_sc.sc_fs; 665 regs->tf_es = frame.sf_sc.sc_es; 666 regs->tf_ds = frame.sf_sc.sc_ds; 667 regs->tf_edi = frame.sf_sc.sc_edi; 668 regs->tf_esi = frame.sf_sc.sc_esi; 669 regs->tf_ebp = frame.sf_sc.sc_ebp; 670 regs->tf_ebx = frame.sf_sc.sc_ebx; 671 regs->tf_edx = frame.sf_sc.sc_edx; 672 regs->tf_ecx = frame.sf_sc.sc_ecx; 673 regs->tf_eax = frame.sf_sc.sc_eax; 674 regs->tf_eip = frame.sf_sc.sc_eip; 675 regs->tf_cs = frame.sf_sc.sc_cs; 676 regs->tf_eflags = eflags; 677 regs->tf_esp = frame.sf_sc.sc_esp_at_signal; 678 regs->tf_ss = frame.sf_sc.sc_ss; 679 680 return (EJUSTRETURN); 681 } 682 683 /* 684 * System call to cleanup state after a signal 685 * has been taken. Reset signal mask and 686 * stack state from context left by rt_sendsig (above). 687 * Return to previous pc and psl as specified by 688 * context left by sendsig. Check carefully to 689 * make sure that the user has not modified the 690 * psl to gain improper privileges or to cause 691 * a machine fault. 692 */ 693 int 694 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args) 695 { 696 struct l_ucontext uc; 697 struct l_sigcontext *context; 698 sigset_t bmask; 699 l_stack_t *lss; 700 stack_t ss; 701 struct trapframe *regs; 702 int eflags; 703 ksiginfo_t ksi; 704 705 regs = td->td_frame; 706 707 #ifdef DEBUG 708 if (ldebug(rt_sigreturn)) 709 printf(ARGS(rt_sigreturn, "%p"), (void *)args->ucp); 710 #endif 711 /* 712 * The trampoline code hands us the ucontext. 713 * It is unsafe to keep track of it ourselves, in the event that a 714 * program jumps out of a signal handler. 715 */ 716 if (copyin(args->ucp, &uc, sizeof(uc)) != 0) 717 return (EFAULT); 718 719 context = &uc.uc_mcontext; 720 721 /* Check for security violations. */ 722 #define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) 723 eflags = context->sc_eflags; 724 if (!EFLAGS_SECURE(eflags, regs->tf_eflags)) 725 return (EINVAL); 726 727 /* 728 * Don't allow users to load a valid privileged %cs. Let the 729 * hardware check for invalid selectors, excess privilege in 730 * other selectors, invalid %eip's and invalid %esp's. 731 */ 732 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) 733 if (!CS_SECURE(context->sc_cs)) { 734 ksiginfo_init_trap(&ksi); 735 ksi.ksi_signo = SIGBUS; 736 ksi.ksi_code = BUS_OBJERR; 737 ksi.ksi_trapno = T_PROTFLT; 738 ksi.ksi_addr = (void *)regs->tf_eip; 739 trapsignal(td, &ksi); 740 return (EINVAL); 741 } 742 743 linux_to_bsd_sigset(&uc.uc_sigmask, &bmask); 744 kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0); 745 746 /* Restore signal context. */ 747 /* %gs was restored by the trampoline. */ 748 regs->tf_fs = context->sc_fs; 749 regs->tf_es = context->sc_es; 750 regs->tf_ds = context->sc_ds; 751 regs->tf_edi = context->sc_edi; 752 regs->tf_esi = context->sc_esi; 753 regs->tf_ebp = context->sc_ebp; 754 regs->tf_ebx = context->sc_ebx; 755 regs->tf_edx = context->sc_edx; 756 regs->tf_ecx = context->sc_ecx; 757 regs->tf_eax = context->sc_eax; 758 regs->tf_eip = context->sc_eip; 759 regs->tf_cs = context->sc_cs; 760 regs->tf_eflags = eflags; 761 regs->tf_esp = context->sc_esp_at_signal; 762 regs->tf_ss = context->sc_ss; 763 764 /* Call sigaltstack & ignore results. */ 765 lss = &uc.uc_stack; 766 ss.ss_sp = lss->ss_sp; 767 ss.ss_size = lss->ss_size; 768 ss.ss_flags = linux_to_bsd_sigaltstack(lss->ss_flags); 769 770 #ifdef DEBUG 771 if (ldebug(rt_sigreturn)) 772 printf(LMSG("rt_sigret flags: 0x%x, sp: %p, ss: 0x%x, mask: 0x%x"), 773 ss.ss_flags, ss.ss_sp, ss.ss_size, context->sc_mask); 774 #endif 775 (void)kern_sigaltstack(td, &ss, NULL); 776 777 return (EJUSTRETURN); 778 } 779 780 static int 781 linux_fetch_syscall_args(struct thread *td) 782 { 783 struct proc *p; 784 struct trapframe *frame; 785 struct syscall_args *sa; 786 787 p = td->td_proc; 788 frame = td->td_frame; 789 sa = &td->td_sa; 790 791 sa->code = frame->tf_eax; 792 sa->args[0] = frame->tf_ebx; 793 sa->args[1] = frame->tf_ecx; 794 sa->args[2] = frame->tf_edx; 795 sa->args[3] = frame->tf_esi; 796 sa->args[4] = frame->tf_edi; 797 sa->args[5] = frame->tf_ebp; /* Unconfirmed */ 798 799 if (sa->code >= p->p_sysent->sv_size) 800 /* nosys */ 801 sa->callp = &p->p_sysent->sv_table[p->p_sysent->sv_size - 1]; 802 else 803 sa->callp = &p->p_sysent->sv_table[sa->code]; 804 sa->narg = sa->callp->sy_narg; 805 806 td->td_retval[0] = 0; 807 td->td_retval[1] = frame->tf_edx; 808 809 return (0); 810 } 811 812 /* 813 * exec_setregs may initialize some registers differently than Linux 814 * does, thus potentially confusing Linux binaries. If necessary, we 815 * override the exec_setregs default(s) here. 816 */ 817 static void 818 linux_exec_setregs(struct thread *td, struct image_params *imgp, u_long stack) 819 { 820 struct pcb *pcb = td->td_pcb; 821 822 exec_setregs(td, imgp, stack); 823 824 /* Linux sets %gs to 0, we default to _udatasel. */ 825 pcb->pcb_gs = 0; 826 load_gs(0); 827 828 pcb->pcb_initial_npxcw = __LINUX_NPXCW__; 829 } 830 831 static void 832 linux_get_machine(const char **dst) 833 { 834 835 switch (cpu_class) { 836 case CPUCLASS_686: 837 *dst = "i686"; 838 break; 839 case CPUCLASS_586: 840 *dst = "i586"; 841 break; 842 case CPUCLASS_486: 843 *dst = "i486"; 844 break; 845 default: 846 *dst = "i386"; 847 } 848 } 849 850 struct sysentvec linux_sysvec = { 851 .sv_size = LINUX_SYS_MAXSYSCALL, 852 .sv_table = linux_sysent, 853 .sv_errsize = ELAST + 1, 854 .sv_errtbl = linux_errtbl, 855 .sv_transtrap = linux_translate_traps, 856 .sv_fixup = linux_fixup, 857 .sv_sendsig = linux_sendsig, 858 .sv_sigcode = &_binary_linux_locore_o_start, 859 .sv_szsigcode = &linux_szsigcode, 860 .sv_name = "Linux a.out", 861 .sv_coredump = NULL, 862 .sv_imgact_try = linux_exec_imgact_try, 863 .sv_minsigstksz = LINUX_MINSIGSTKSZ, 864 .sv_minuser = VM_MIN_ADDRESS, 865 .sv_maxuser = VM_MAXUSER_ADDRESS, 866 .sv_usrstack = LINUX_USRSTACK, 867 .sv_psstrings = PS_STRINGS, 868 .sv_stackprot = VM_PROT_ALL, 869 .sv_copyout_strings = exec_copyout_strings, 870 .sv_setregs = linux_exec_setregs, 871 .sv_fixlimit = NULL, 872 .sv_maxssiz = NULL, 873 .sv_flags = SV_ABI_LINUX | SV_AOUT | SV_IA32 | SV_ILP32, 874 .sv_set_syscall_retval = cpu_set_syscall_retval, 875 .sv_fetch_syscall_args = linux_fetch_syscall_args, 876 .sv_syscallnames = NULL, 877 .sv_shared_page_base = LINUX_SHAREDPAGE, 878 .sv_shared_page_len = PAGE_SIZE, 879 .sv_schedtail = linux_schedtail, 880 .sv_thread_detach = linux_thread_detach, 881 .sv_trap = NULL, 882 }; 883 INIT_SYSENTVEC(aout_sysvec, &linux_sysvec); 884 885 struct sysentvec elf_linux_sysvec = { 886 .sv_size = LINUX_SYS_MAXSYSCALL, 887 .sv_table = linux_sysent, 888 .sv_errsize = ELAST + 1, 889 .sv_errtbl = linux_errtbl, 890 .sv_transtrap = linux_translate_traps, 891 .sv_fixup = linux_fixup_elf, 892 .sv_sendsig = linux_sendsig, 893 .sv_sigcode = &_binary_linux_locore_o_start, 894 .sv_szsigcode = &linux_szsigcode, 895 .sv_name = "Linux ELF", 896 .sv_coredump = elf32_coredump, 897 .sv_imgact_try = linux_exec_imgact_try, 898 .sv_minsigstksz = LINUX_MINSIGSTKSZ, 899 .sv_minuser = VM_MIN_ADDRESS, 900 .sv_maxuser = VM_MAXUSER_ADDRESS, 901 .sv_usrstack = LINUX_USRSTACK, 902 .sv_psstrings = LINUX_PS_STRINGS, 903 .sv_stackprot = VM_PROT_ALL, 904 .sv_copyout_strings = linux_copyout_strings, 905 .sv_setregs = linux_exec_setregs, 906 .sv_fixlimit = NULL, 907 .sv_maxssiz = NULL, 908 .sv_flags = SV_ABI_LINUX | SV_IA32 | SV_ILP32 | SV_SHP, 909 .sv_set_syscall_retval = cpu_set_syscall_retval, 910 .sv_fetch_syscall_args = linux_fetch_syscall_args, 911 .sv_syscallnames = NULL, 912 .sv_shared_page_base = LINUX_SHAREDPAGE, 913 .sv_shared_page_len = PAGE_SIZE, 914 .sv_schedtail = linux_schedtail, 915 .sv_thread_detach = linux_thread_detach, 916 .sv_trap = NULL, 917 }; 918 919 static void 920 linux_vdso_install(void *param) 921 { 922 923 linux_szsigcode = (&_binary_linux_locore_o_end - 924 &_binary_linux_locore_o_start); 925 926 if (linux_szsigcode > elf_linux_sysvec.sv_shared_page_len) 927 panic("Linux invalid vdso size\n"); 928 929 __elfN(linux_vdso_fixup)(&elf_linux_sysvec); 930 931 linux_shared_page_obj = __elfN(linux_shared_page_init) 932 (&linux_shared_page_mapping); 933 934 __elfN(linux_vdso_reloc)(&elf_linux_sysvec); 935 936 bcopy(elf_linux_sysvec.sv_sigcode, linux_shared_page_mapping, 937 linux_szsigcode); 938 elf_linux_sysvec.sv_shared_page_obj = linux_shared_page_obj; 939 } 940 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC, SI_ORDER_ANY, 941 linux_vdso_install, NULL); 942 943 static void 944 linux_vdso_deinstall(void *param) 945 { 946 947 __elfN(linux_shared_page_fini)(linux_shared_page_obj); 948 } 949 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST, 950 linux_vdso_deinstall, NULL); 951 952 static char GNU_ABI_VENDOR[] = "GNU"; 953 static int GNULINUX_ABI_DESC = 0; 954 955 static bool 956 linux_trans_osrel(const Elf_Note *note, int32_t *osrel) 957 { 958 const Elf32_Word *desc; 959 uintptr_t p; 960 961 p = (uintptr_t)(note + 1); 962 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 963 964 desc = (const Elf32_Word *)p; 965 if (desc[0] != GNULINUX_ABI_DESC) 966 return (false); 967 968 /* 969 * For Linux we encode osrel using the Linux convention of 970 * (version << 16) | (major << 8) | (minor) 971 * See macro in linux_mib.h 972 */ 973 *osrel = LINUX_KERNVER(desc[1], desc[2], desc[3]); 974 975 return (true); 976 } 977 978 static Elf_Brandnote linux_brandnote = { 979 .hdr.n_namesz = sizeof(GNU_ABI_VENDOR), 980 .hdr.n_descsz = 16, /* XXX at least 16 */ 981 .hdr.n_type = 1, 982 .vendor = GNU_ABI_VENDOR, 983 .flags = BN_TRANSLATE_OSREL, 984 .trans_osrel = linux_trans_osrel 985 }; 986 987 static Elf32_Brandinfo linux_brand = { 988 .brand = ELFOSABI_LINUX, 989 .machine = EM_386, 990 .compat_3_brand = "Linux", 991 .emul_path = "/compat/linux", 992 .interp_path = "/lib/ld-linux.so.1", 993 .sysvec = &elf_linux_sysvec, 994 .interp_newpath = NULL, 995 .brand_note = &linux_brandnote, 996 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE 997 }; 998 999 static Elf32_Brandinfo linux_glibc2brand = { 1000 .brand = ELFOSABI_LINUX, 1001 .machine = EM_386, 1002 .compat_3_brand = "Linux", 1003 .emul_path = "/compat/linux", 1004 .interp_path = "/lib/ld-linux.so.2", 1005 .sysvec = &elf_linux_sysvec, 1006 .interp_newpath = NULL, 1007 .brand_note = &linux_brandnote, 1008 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE 1009 }; 1010 1011 static Elf32_Brandinfo linux_muslbrand = { 1012 .brand = ELFOSABI_LINUX, 1013 .machine = EM_386, 1014 .compat_3_brand = "Linux", 1015 .emul_path = "/compat/linux", 1016 .interp_path = "/lib/ld-musl-i386.so.1", 1017 .sysvec = &elf_linux_sysvec, 1018 .interp_newpath = NULL, 1019 .brand_note = &linux_brandnote, 1020 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE 1021 }; 1022 1023 Elf32_Brandinfo *linux_brandlist[] = { 1024 &linux_brand, 1025 &linux_glibc2brand, 1026 &linux_muslbrand, 1027 NULL 1028 }; 1029 1030 static int 1031 linux_elf_modevent(module_t mod, int type, void *data) 1032 { 1033 Elf32_Brandinfo **brandinfo; 1034 int error; 1035 struct linux_ioctl_handler **lihp; 1036 1037 error = 0; 1038 1039 switch(type) { 1040 case MOD_LOAD: 1041 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 1042 ++brandinfo) 1043 if (elf32_insert_brand_entry(*brandinfo) < 0) 1044 error = EINVAL; 1045 if (error == 0) { 1046 SET_FOREACH(lihp, linux_ioctl_handler_set) 1047 linux_ioctl_register_handler(*lihp); 1048 LIST_INIT(&futex_list); 1049 mtx_init(&futex_mtx, "ftllk", NULL, MTX_DEF); 1050 linux_exit_tag = EVENTHANDLER_REGISTER(process_exit, linux_proc_exit, 1051 NULL, 1000); 1052 linux_exec_tag = EVENTHANDLER_REGISTER(process_exec, linux_proc_exec, 1053 NULL, 1000); 1054 linux_thread_dtor_tag = EVENTHANDLER_REGISTER(thread_dtor, 1055 linux_thread_dtor, NULL, EVENTHANDLER_PRI_ANY); 1056 linux_get_machine(&linux_kplatform); 1057 linux_szplatform = roundup(strlen(linux_kplatform) + 1, 1058 sizeof(char *)); 1059 linux_osd_jail_register(); 1060 stclohz = (stathz ? stathz : hz); 1061 if (bootverbose) 1062 printf("Linux ELF exec handler installed\n"); 1063 } else 1064 printf("cannot insert Linux ELF brand handler\n"); 1065 break; 1066 case MOD_UNLOAD: 1067 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 1068 ++brandinfo) 1069 if (elf32_brand_inuse(*brandinfo)) 1070 error = EBUSY; 1071 if (error == 0) { 1072 for (brandinfo = &linux_brandlist[0]; 1073 *brandinfo != NULL; ++brandinfo) 1074 if (elf32_remove_brand_entry(*brandinfo) < 0) 1075 error = EINVAL; 1076 } 1077 if (error == 0) { 1078 SET_FOREACH(lihp, linux_ioctl_handler_set) 1079 linux_ioctl_unregister_handler(*lihp); 1080 mtx_destroy(&futex_mtx); 1081 EVENTHANDLER_DEREGISTER(process_exit, linux_exit_tag); 1082 EVENTHANDLER_DEREGISTER(process_exec, linux_exec_tag); 1083 EVENTHANDLER_DEREGISTER(thread_dtor, linux_thread_dtor_tag); 1084 linux_osd_jail_deregister(); 1085 if (bootverbose) 1086 printf("Linux ELF exec handler removed\n"); 1087 } else 1088 printf("Could not deinstall ELF interpreter entry\n"); 1089 break; 1090 default: 1091 return (EOPNOTSUPP); 1092 } 1093 return (error); 1094 } 1095 1096 static moduledata_t linux_elf_mod = { 1097 "linuxelf", 1098 linux_elf_modevent, 1099 0 1100 }; 1101 1102 DECLARE_MODULE_TIED(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY); 1103 FEATURE(linux, "Linux 32bit support"); 1104