linux_sysvec.c revision 141469
1/*- 2 * Copyright (c) 1994-1996 S�ren Schmidt 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD: head/sys/i386/linux/linux_sysvec.c 141469 2005-02-07 18:37:51Z jhb $"); 31 32/* XXX we use functions that might not exist. */ 33#include "opt_compat.h" 34 35#ifndef COMPAT_43 36#error "Unable to compile Linux-emulator due to missing COMPAT_43 option!" 37#endif 38 39#include <sys/param.h> 40#include <sys/systm.h> 41#include <sys/exec.h> 42#include <sys/imgact.h> 43#include <sys/imgact_aout.h> 44#include <sys/imgact_elf.h> 45#include <sys/kernel.h> 46#include <sys/lock.h> 47#include <sys/malloc.h> 48#include <sys/module.h> 49#include <sys/mutex.h> 50#include <sys/proc.h> 51#include <sys/signalvar.h> 52#include <sys/syscallsubr.h> 53#include <sys/sysent.h> 54#include <sys/sysproto.h> 55#include <sys/vnode.h> 56 57#include <vm/vm.h> 58#include <vm/pmap.h> 59#include <vm/vm_extern.h> 60#include <vm/vm_map.h> 61#include <vm/vm_object.h> 62#include <vm/vm_page.h> 63#include <vm/vm_param.h> 64 65#include <machine/cpu.h> 66#include <machine/md_var.h> 67#include <machine/pcb.h> 68 69#include <i386/linux/linux.h> 70#include <i386/linux/linux_proto.h> 71#include <compat/linux/linux_mib.h> 72#include <compat/linux/linux_signal.h> 73#include <compat/linux/linux_util.h> 74 75MODULE_VERSION(linux, 1); 76MODULE_DEPEND(linux, sysvmsg, 1, 1, 1); 77MODULE_DEPEND(linux, sysvsem, 1, 1, 1); 78MODULE_DEPEND(linux, sysvshm, 1, 1, 1); 79 80MALLOC_DEFINE(M_LINUX, "linux", "Linux mode structures"); 81 82#if BYTE_ORDER == LITTLE_ENDIAN 83#define SHELLMAGIC 0x2123 /* #! */ 84#else 85#define SHELLMAGIC 0x2321 86#endif 87 88/* 89 * Allow the sendsig functions to use the ldebug() facility 90 * even though they are not syscalls themselves. Map them 91 * to syscall 0. This is slightly less bogus than using 92 * ldebug(sigreturn). 93 */ 94#define LINUX_SYS_linux_rt_sendsig 0 95#define LINUX_SYS_linux_sendsig 0 96 97#define fldcw(addr) __asm("fldcw %0" : : "m" (*(addr))) 98#define __LINUX_NPXCW__ 0x37f 99 100extern char linux_sigcode[]; 101extern int linux_szsigcode; 102 103extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL]; 104 105SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler); 106 107static int linux_fixup(register_t **stack_base, 108 struct image_params *iparams); 109static int elf_linux_fixup(register_t **stack_base, 110 struct image_params *iparams); 111static void linux_prepsyscall(struct trapframe *tf, int *args, u_int *code, 112 caddr_t *params); 113static void linux_sendsig(sig_t catcher, int sig, sigset_t *mask, 114 u_long code); 115static void exec_linux_setregs(struct thread *td, u_long entry, 116 u_long stack, u_long ps_strings); 117 118/* 119 * Linux syscalls return negative errno's, we do positive and map them 120 */ 121static int bsd_to_linux_errno[ELAST + 1] = { 122 -0, -1, -2, -3, -4, -5, -6, -7, -8, -9, 123 -10, -35, -12, -13, -14, -15, -16, -17, -18, -19, 124 -20, -21, -22, -23, -24, -25, -26, -27, -28, -29, 125 -30, -31, -32, -33, -34, -11,-115,-114, -88, -89, 126 -90, -91, -92, -93, -94, -95, -96, -97, -98, -99, 127 -100,-101,-102,-103,-104,-105,-106,-107,-108,-109, 128 -110,-111, -40, -36,-112,-113, -39, -11, -87,-122, 129 -116, -66, -6, -6, -6, -6, -6, -37, -38, -9, 130 -6, -6, -43, -42, -75, -6, -84 131}; 132 133int bsd_to_linux_signal[LINUX_SIGTBLSZ] = { 134 LINUX_SIGHUP, LINUX_SIGINT, LINUX_SIGQUIT, LINUX_SIGILL, 135 LINUX_SIGTRAP, LINUX_SIGABRT, 0, LINUX_SIGFPE, 136 LINUX_SIGKILL, LINUX_SIGBUS, LINUX_SIGSEGV, LINUX_SIGSYS, 137 LINUX_SIGPIPE, LINUX_SIGALRM, LINUX_SIGTERM, LINUX_SIGURG, 138 LINUX_SIGSTOP, LINUX_SIGTSTP, LINUX_SIGCONT, LINUX_SIGCHLD, 139 LINUX_SIGTTIN, LINUX_SIGTTOU, LINUX_SIGIO, LINUX_SIGXCPU, 140 LINUX_SIGXFSZ, LINUX_SIGVTALRM, LINUX_SIGPROF, LINUX_SIGWINCH, 141 0, LINUX_SIGUSR1, LINUX_SIGUSR2 142}; 143 144int linux_to_bsd_signal[LINUX_SIGTBLSZ] = { 145 SIGHUP, SIGINT, SIGQUIT, SIGILL, 146 SIGTRAP, SIGABRT, SIGBUS, SIGFPE, 147 SIGKILL, SIGUSR1, SIGSEGV, SIGUSR2, 148 SIGPIPE, SIGALRM, SIGTERM, SIGBUS, 149 SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP, 150 SIGTTIN, SIGTTOU, SIGURG, SIGXCPU, 151 SIGXFSZ, SIGVTALRM, SIGPROF, SIGWINCH, 152 SIGIO, SIGURG, SIGSYS 153}; 154 155#define LINUX_T_UNKNOWN 255 156static int _bsd_to_linux_trapcode[] = { 157 LINUX_T_UNKNOWN, /* 0 */ 158 6, /* 1 T_PRIVINFLT */ 159 LINUX_T_UNKNOWN, /* 2 */ 160 3, /* 3 T_BPTFLT */ 161 LINUX_T_UNKNOWN, /* 4 */ 162 LINUX_T_UNKNOWN, /* 5 */ 163 16, /* 6 T_ARITHTRAP */ 164 254, /* 7 T_ASTFLT */ 165 LINUX_T_UNKNOWN, /* 8 */ 166 13, /* 9 T_PROTFLT */ 167 1, /* 10 T_TRCTRAP */ 168 LINUX_T_UNKNOWN, /* 11 */ 169 14, /* 12 T_PAGEFLT */ 170 LINUX_T_UNKNOWN, /* 13 */ 171 17, /* 14 T_ALIGNFLT */ 172 LINUX_T_UNKNOWN, /* 15 */ 173 LINUX_T_UNKNOWN, /* 16 */ 174 LINUX_T_UNKNOWN, /* 17 */ 175 0, /* 18 T_DIVIDE */ 176 2, /* 19 T_NMI */ 177 4, /* 20 T_OFLOW */ 178 5, /* 21 T_BOUND */ 179 7, /* 22 T_DNA */ 180 8, /* 23 T_DOUBLEFLT */ 181 9, /* 24 T_FPOPFLT */ 182 10, /* 25 T_TSSFLT */ 183 11, /* 26 T_SEGNPFLT */ 184 12, /* 27 T_STKFLT */ 185 18, /* 28 T_MCHK */ 186 19, /* 29 T_XMMFLT */ 187 15 /* 30 T_RESERVED */ 188}; 189#define bsd_to_linux_trapcode(code) \ 190 ((code)<sizeof(_bsd_to_linux_trapcode)/sizeof(*_bsd_to_linux_trapcode)? \ 191 _bsd_to_linux_trapcode[(code)]: \ 192 LINUX_T_UNKNOWN) 193 194/* 195 * If FreeBSD & Linux have a difference of opinion about what a trap 196 * means, deal with it here. 197 * 198 * MPSAFE 199 */ 200static int 201translate_traps(int signal, int trap_code) 202{ 203 if (signal != SIGBUS) 204 return signal; 205 switch (trap_code) { 206 case T_PROTFLT: 207 case T_TSSFLT: 208 case T_DOUBLEFLT: 209 case T_PAGEFLT: 210 return SIGSEGV; 211 default: 212 return signal; 213 } 214} 215 216static int 217linux_fixup(register_t **stack_base, struct image_params *imgp) 218{ 219 register_t *argv, *envp; 220 221 argv = *stack_base; 222 envp = *stack_base + (imgp->args->argc + 1); 223 (*stack_base)--; 224 **stack_base = (intptr_t)(void *)envp; 225 (*stack_base)--; 226 **stack_base = (intptr_t)(void *)argv; 227 (*stack_base)--; 228 **stack_base = imgp->args->argc; 229 return 0; 230} 231 232static int 233elf_linux_fixup(register_t **stack_base, struct image_params *imgp) 234{ 235 Elf32_Auxargs *args; 236 register_t *pos; 237 238 KASSERT(curthread->td_proc == imgp->proc && 239 (curthread->td_proc->p_flag & P_SA) == 0, 240 ("unsafe elf_linux_fixup(), should be curproc")); 241 args = (Elf32_Auxargs *)imgp->auxargs; 242 pos = *stack_base + (imgp->args->argc + imgp->args->envc + 2); 243 244 if (args->trace) 245 AUXARGS_ENTRY(pos, AT_DEBUG, 1); 246 if (args->execfd != -1) 247 AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd); 248 AUXARGS_ENTRY(pos, AT_PHDR, args->phdr); 249 AUXARGS_ENTRY(pos, AT_PHENT, args->phent); 250 AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum); 251 AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz); 252 AUXARGS_ENTRY(pos, AT_FLAGS, args->flags); 253 AUXARGS_ENTRY(pos, AT_ENTRY, args->entry); 254 AUXARGS_ENTRY(pos, AT_BASE, args->base); 255 AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid); 256 AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid); 257 AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid); 258 AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid); 259 AUXARGS_ENTRY(pos, AT_NULL, 0); 260 261 free(imgp->auxargs, M_TEMP); 262 imgp->auxargs = NULL; 263 264 (*stack_base)--; 265 **stack_base = (register_t)imgp->args->argc; 266 return 0; 267} 268 269extern int _ucodesel, _udatasel; 270extern unsigned long linux_sznonrtsigcode; 271 272static void 273linux_rt_sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code) 274{ 275 struct thread *td = curthread; 276 struct proc *p = td->td_proc; 277 struct sigacts *psp; 278 struct trapframe *regs; 279 struct l_rt_sigframe *fp, frame; 280 int oonstack; 281 282 PROC_LOCK_ASSERT(p, MA_OWNED); 283 psp = p->p_sigacts; 284 mtx_assert(&psp->ps_mtx, MA_OWNED); 285 regs = td->td_frame; 286 oonstack = sigonstack(regs->tf_esp); 287 288#ifdef DEBUG 289 if (ldebug(rt_sendsig)) 290 printf(ARGS(rt_sendsig, "%p, %d, %p, %lu"), 291 catcher, sig, (void*)mask, code); 292#endif 293 /* 294 * Allocate space for the signal handler context. 295 */ 296 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack && 297 SIGISMEMBER(psp->ps_sigonstack, sig)) { 298 fp = (struct l_rt_sigframe *)(td->td_sigstk.ss_sp + 299 td->td_sigstk.ss_size - sizeof(struct l_rt_sigframe)); 300 } else 301 fp = (struct l_rt_sigframe *)regs->tf_esp - 1; 302 mtx_unlock(&psp->ps_mtx); 303 304 /* 305 * Build the argument list for the signal handler. 306 */ 307 if (p->p_sysent->sv_sigtbl) 308 if (sig <= p->p_sysent->sv_sigsize) 309 sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)]; 310 311 bzero(&frame, sizeof(frame)); 312 313 frame.sf_handler = catcher; 314 frame.sf_sig = sig; 315 frame.sf_siginfo = &fp->sf_si; 316 frame.sf_ucontext = &fp->sf_sc; 317 318 /* Fill in POSIX parts */ 319 frame.sf_si.lsi_signo = sig; 320 frame.sf_si.lsi_code = code; 321 frame.sf_si.lsi_addr = (void *)regs->tf_err; 322 323 /* 324 * Build the signal context to be used by sigreturn. 325 */ 326 frame.sf_sc.uc_flags = 0; /* XXX ??? */ 327 frame.sf_sc.uc_link = NULL; /* XXX ??? */ 328 329 frame.sf_sc.uc_stack.ss_sp = td->td_sigstk.ss_sp; 330 frame.sf_sc.uc_stack.ss_size = td->td_sigstk.ss_size; 331 frame.sf_sc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) 332 ? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE; 333 PROC_UNLOCK(p); 334 335 bsd_to_linux_sigset(mask, &frame.sf_sc.uc_sigmask); 336 337 frame.sf_sc.uc_mcontext.sc_mask = frame.sf_sc.uc_sigmask.__bits[0]; 338 frame.sf_sc.uc_mcontext.sc_gs = rgs(); 339 frame.sf_sc.uc_mcontext.sc_fs = regs->tf_fs; 340 frame.sf_sc.uc_mcontext.sc_es = regs->tf_es; 341 frame.sf_sc.uc_mcontext.sc_ds = regs->tf_ds; 342 frame.sf_sc.uc_mcontext.sc_edi = regs->tf_edi; 343 frame.sf_sc.uc_mcontext.sc_esi = regs->tf_esi; 344 frame.sf_sc.uc_mcontext.sc_ebp = regs->tf_ebp; 345 frame.sf_sc.uc_mcontext.sc_ebx = regs->tf_ebx; 346 frame.sf_sc.uc_mcontext.sc_edx = regs->tf_edx; 347 frame.sf_sc.uc_mcontext.sc_ecx = regs->tf_ecx; 348 frame.sf_sc.uc_mcontext.sc_eax = regs->tf_eax; 349 frame.sf_sc.uc_mcontext.sc_eip = regs->tf_eip; 350 frame.sf_sc.uc_mcontext.sc_cs = regs->tf_cs; 351 frame.sf_sc.uc_mcontext.sc_eflags = regs->tf_eflags; 352 frame.sf_sc.uc_mcontext.sc_esp_at_signal = regs->tf_esp; 353 frame.sf_sc.uc_mcontext.sc_ss = regs->tf_ss; 354 frame.sf_sc.uc_mcontext.sc_err = regs->tf_err; 355 frame.sf_sc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code); 356 357#ifdef DEBUG 358 if (ldebug(rt_sendsig)) 359 printf(LMSG("rt_sendsig flags: 0x%x, sp: %p, ss: 0x%x, mask: 0x%x"), 360 frame.sf_sc.uc_stack.ss_flags, td->td_sigstk.ss_sp, 361 td->td_sigstk.ss_size, frame.sf_sc.uc_mcontext.sc_mask); 362#endif 363 364 if (copyout(&frame, fp, sizeof(frame)) != 0) { 365 /* 366 * Process has trashed its stack; give it an illegal 367 * instruction to halt it in its tracks. 368 */ 369#ifdef DEBUG 370 if (ldebug(rt_sendsig)) 371 printf(LMSG("rt_sendsig: bad stack %p, oonstack=%x"), 372 fp, oonstack); 373#endif 374 PROC_LOCK(p); 375 sigexit(td, SIGILL); 376 } 377 378 /* 379 * Build context to run handler in. 380 */ 381 regs->tf_esp = (int)fp; 382 regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode) + 383 linux_sznonrtsigcode; 384 regs->tf_eflags &= ~(PSL_T | PSL_VM); 385 regs->tf_cs = _ucodesel; 386 regs->tf_ds = _udatasel; 387 regs->tf_es = _udatasel; 388 regs->tf_fs = _udatasel; 389 regs->tf_ss = _udatasel; 390 PROC_LOCK(p); 391 mtx_lock(&psp->ps_mtx); 392} 393 394 395/* 396 * Send an interrupt to process. 397 * 398 * Stack is set up to allow sigcode stored 399 * in u. to call routine, followed by kcall 400 * to sigreturn routine below. After sigreturn 401 * resets the signal mask, the stack, and the 402 * frame pointer, it returns to the user 403 * specified pc, psl. 404 */ 405static void 406linux_sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code) 407{ 408 struct thread *td = curthread; 409 struct proc *p = td->td_proc; 410 struct sigacts *psp; 411 struct trapframe *regs; 412 struct l_sigframe *fp, frame; 413 l_sigset_t lmask; 414 int oonstack, i; 415 416 PROC_LOCK_ASSERT(p, MA_OWNED); 417 psp = p->p_sigacts; 418 mtx_assert(&psp->ps_mtx, MA_OWNED); 419 if (SIGISMEMBER(psp->ps_siginfo, sig)) { 420 /* Signal handler installed with SA_SIGINFO. */ 421 linux_rt_sendsig(catcher, sig, mask, code); 422 return; 423 } 424 425 regs = td->td_frame; 426 oonstack = sigonstack(regs->tf_esp); 427 428#ifdef DEBUG 429 if (ldebug(sendsig)) 430 printf(ARGS(sendsig, "%p, %d, %p, %lu"), 431 catcher, sig, (void*)mask, code); 432#endif 433 434 /* 435 * Allocate space for the signal handler context. 436 */ 437 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack && 438 SIGISMEMBER(psp->ps_sigonstack, sig)) { 439 fp = (struct l_sigframe *)(td->td_sigstk.ss_sp + 440 td->td_sigstk.ss_size - sizeof(struct l_sigframe)); 441 } else 442 fp = (struct l_sigframe *)regs->tf_esp - 1; 443 mtx_unlock(&psp->ps_mtx); 444 PROC_UNLOCK(p); 445 446 /* 447 * Build the argument list for the signal handler. 448 */ 449 if (p->p_sysent->sv_sigtbl) 450 if (sig <= p->p_sysent->sv_sigsize) 451 sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)]; 452 453 bzero(&frame, sizeof(frame)); 454 455 frame.sf_handler = catcher; 456 frame.sf_sig = sig; 457 458 bsd_to_linux_sigset(mask, &lmask); 459 460 /* 461 * Build the signal context to be used by sigreturn. 462 */ 463 frame.sf_sc.sc_mask = lmask.__bits[0]; 464 frame.sf_sc.sc_gs = rgs(); 465 frame.sf_sc.sc_fs = regs->tf_fs; 466 frame.sf_sc.sc_es = regs->tf_es; 467 frame.sf_sc.sc_ds = regs->tf_ds; 468 frame.sf_sc.sc_edi = regs->tf_edi; 469 frame.sf_sc.sc_esi = regs->tf_esi; 470 frame.sf_sc.sc_ebp = regs->tf_ebp; 471 frame.sf_sc.sc_ebx = regs->tf_ebx; 472 frame.sf_sc.sc_edx = regs->tf_edx; 473 frame.sf_sc.sc_ecx = regs->tf_ecx; 474 frame.sf_sc.sc_eax = regs->tf_eax; 475 frame.sf_sc.sc_eip = regs->tf_eip; 476 frame.sf_sc.sc_cs = regs->tf_cs; 477 frame.sf_sc.sc_eflags = regs->tf_eflags; 478 frame.sf_sc.sc_esp_at_signal = regs->tf_esp; 479 frame.sf_sc.sc_ss = regs->tf_ss; 480 frame.sf_sc.sc_err = regs->tf_err; 481 frame.sf_sc.sc_trapno = bsd_to_linux_trapcode(code); 482 483 for (i = 0; i < (LINUX_NSIG_WORDS-1); i++) 484 frame.sf_extramask[i] = lmask.__bits[i+1]; 485 486 if (copyout(&frame, fp, sizeof(frame)) != 0) { 487 /* 488 * Process has trashed its stack; give it an illegal 489 * instruction to halt it in its tracks. 490 */ 491 PROC_LOCK(p); 492 sigexit(td, SIGILL); 493 } 494 495 /* 496 * Build context to run handler in. 497 */ 498 regs->tf_esp = (int)fp; 499 regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode); 500 regs->tf_eflags &= ~(PSL_T | PSL_VM); 501 regs->tf_cs = _ucodesel; 502 regs->tf_ds = _udatasel; 503 regs->tf_es = _udatasel; 504 regs->tf_fs = _udatasel; 505 regs->tf_ss = _udatasel; 506 PROC_LOCK(p); 507 mtx_lock(&psp->ps_mtx); 508} 509 510/* 511 * System call to cleanup state after a signal 512 * has been taken. Reset signal mask and 513 * stack state from context left by sendsig (above). 514 * Return to previous pc and psl as specified by 515 * context left by sendsig. Check carefully to 516 * make sure that the user has not modified the 517 * psl to gain improper privileges or to cause 518 * a machine fault. 519 */ 520int 521linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args) 522{ 523 struct proc *p = td->td_proc; 524 struct l_sigframe frame; 525 struct trapframe *regs; 526 l_sigset_t lmask; 527 int eflags, i; 528 529 regs = td->td_frame; 530 531#ifdef DEBUG 532 if (ldebug(sigreturn)) 533 printf(ARGS(sigreturn, "%p"), (void *)args->sfp); 534#endif 535 /* 536 * The trampoline code hands us the sigframe. 537 * It is unsafe to keep track of it ourselves, in the event that a 538 * program jumps out of a signal handler. 539 */ 540 if (copyin(args->sfp, &frame, sizeof(frame)) != 0) 541 return (EFAULT); 542 543 /* 544 * Check for security violations. 545 */ 546#define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) 547 eflags = frame.sf_sc.sc_eflags; 548 /* 549 * XXX do allow users to change the privileged flag PSL_RF. The 550 * cpu sets PSL_RF in tf_eflags for faults. Debuggers should 551 * sometimes set it there too. tf_eflags is kept in the signal 552 * context during signal handling and there is no other place 553 * to remember it, so the PSL_RF bit may be corrupted by the 554 * signal handler without us knowing. Corruption of the PSL_RF 555 * bit at worst causes one more or one less debugger trap, so 556 * allowing it is fairly harmless. 557 */ 558 if (!EFLAGS_SECURE(eflags & ~PSL_RF, regs->tf_eflags & ~PSL_RF)) 559 return(EINVAL); 560 561 /* 562 * Don't allow users to load a valid privileged %cs. Let the 563 * hardware check for invalid selectors, excess privilege in 564 * other selectors, invalid %eip's and invalid %esp's. 565 */ 566#define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) 567 if (!CS_SECURE(frame.sf_sc.sc_cs)) { 568 trapsignal(td, SIGBUS, T_PROTFLT); 569 return(EINVAL); 570 } 571 572 lmask.__bits[0] = frame.sf_sc.sc_mask; 573 for (i = 0; i < (LINUX_NSIG_WORDS-1); i++) 574 lmask.__bits[i+1] = frame.sf_extramask[i]; 575 PROC_LOCK(p); 576 linux_to_bsd_sigset(&lmask, &td->td_sigmask); 577 SIG_CANTMASK(td->td_sigmask); 578 signotify(td); 579 PROC_UNLOCK(p); 580 581 /* 582 * Restore signal context. 583 */ 584 /* %gs was restored by the trampoline. */ 585 regs->tf_fs = frame.sf_sc.sc_fs; 586 regs->tf_es = frame.sf_sc.sc_es; 587 regs->tf_ds = frame.sf_sc.sc_ds; 588 regs->tf_edi = frame.sf_sc.sc_edi; 589 regs->tf_esi = frame.sf_sc.sc_esi; 590 regs->tf_ebp = frame.sf_sc.sc_ebp; 591 regs->tf_ebx = frame.sf_sc.sc_ebx; 592 regs->tf_edx = frame.sf_sc.sc_edx; 593 regs->tf_ecx = frame.sf_sc.sc_ecx; 594 regs->tf_eax = frame.sf_sc.sc_eax; 595 regs->tf_eip = frame.sf_sc.sc_eip; 596 regs->tf_cs = frame.sf_sc.sc_cs; 597 regs->tf_eflags = eflags; 598 regs->tf_esp = frame.sf_sc.sc_esp_at_signal; 599 regs->tf_ss = frame.sf_sc.sc_ss; 600 601 return (EJUSTRETURN); 602} 603 604/* 605 * System call to cleanup state after a signal 606 * has been taken. Reset signal mask and 607 * stack state from context left by rt_sendsig (above). 608 * Return to previous pc and psl as specified by 609 * context left by sendsig. Check carefully to 610 * make sure that the user has not modified the 611 * psl to gain improper privileges or to cause 612 * a machine fault. 613 */ 614int 615linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args) 616{ 617 struct proc *p = td->td_proc; 618 struct l_ucontext uc; 619 struct l_sigcontext *context; 620 l_stack_t *lss; 621 stack_t ss; 622 struct trapframe *regs; 623 int eflags; 624 625 regs = td->td_frame; 626 627#ifdef DEBUG 628 if (ldebug(rt_sigreturn)) 629 printf(ARGS(rt_sigreturn, "%p"), (void *)args->ucp); 630#endif 631 /* 632 * The trampoline code hands us the ucontext. 633 * It is unsafe to keep track of it ourselves, in the event that a 634 * program jumps out of a signal handler. 635 */ 636 if (copyin(args->ucp, &uc, sizeof(uc)) != 0) 637 return (EFAULT); 638 639 context = &uc.uc_mcontext; 640 641 /* 642 * Check for security violations. 643 */ 644#define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) 645 eflags = context->sc_eflags; 646 /* 647 * XXX do allow users to change the privileged flag PSL_RF. The 648 * cpu sets PSL_RF in tf_eflags for faults. Debuggers should 649 * sometimes set it there too. tf_eflags is kept in the signal 650 * context during signal handling and there is no other place 651 * to remember it, so the PSL_RF bit may be corrupted by the 652 * signal handler without us knowing. Corruption of the PSL_RF 653 * bit at worst causes one more or one less debugger trap, so 654 * allowing it is fairly harmless. 655 */ 656 if (!EFLAGS_SECURE(eflags & ~PSL_RF, regs->tf_eflags & ~PSL_RF)) 657 return(EINVAL); 658 659 /* 660 * Don't allow users to load a valid privileged %cs. Let the 661 * hardware check for invalid selectors, excess privilege in 662 * other selectors, invalid %eip's and invalid %esp's. 663 */ 664#define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) 665 if (!CS_SECURE(context->sc_cs)) { 666 trapsignal(td, SIGBUS, T_PROTFLT); 667 return(EINVAL); 668 } 669 670 PROC_LOCK(p); 671 linux_to_bsd_sigset(&uc.uc_sigmask, &td->td_sigmask); 672 SIG_CANTMASK(td->td_sigmask); 673 signotify(td); 674 PROC_UNLOCK(p); 675 676 /* 677 * Restore signal context 678 */ 679 /* %gs was restored by the trampoline. */ 680 regs->tf_fs = context->sc_fs; 681 regs->tf_es = context->sc_es; 682 regs->tf_ds = context->sc_ds; 683 regs->tf_edi = context->sc_edi; 684 regs->tf_esi = context->sc_esi; 685 regs->tf_ebp = context->sc_ebp; 686 regs->tf_ebx = context->sc_ebx; 687 regs->tf_edx = context->sc_edx; 688 regs->tf_ecx = context->sc_ecx; 689 regs->tf_eax = context->sc_eax; 690 regs->tf_eip = context->sc_eip; 691 regs->tf_cs = context->sc_cs; 692 regs->tf_eflags = eflags; 693 regs->tf_esp = context->sc_esp_at_signal; 694 regs->tf_ss = context->sc_ss; 695 696 /* 697 * call sigaltstack & ignore results.. 698 */ 699 lss = &uc.uc_stack; 700 ss.ss_sp = lss->ss_sp; 701 ss.ss_size = lss->ss_size; 702 ss.ss_flags = linux_to_bsd_sigaltstack(lss->ss_flags); 703 704#ifdef DEBUG 705 if (ldebug(rt_sigreturn)) 706 printf(LMSG("rt_sigret flags: 0x%x, sp: %p, ss: 0x%x, mask: 0x%x"), 707 ss.ss_flags, ss.ss_sp, ss.ss_size, context->sc_mask); 708#endif 709 (void)kern_sigaltstack(td, &ss, NULL); 710 711 return (EJUSTRETURN); 712} 713 714/* 715 * MPSAFE 716 */ 717static void 718linux_prepsyscall(struct trapframe *tf, int *args, u_int *code, caddr_t *params) 719{ 720 args[0] = tf->tf_ebx; 721 args[1] = tf->tf_ecx; 722 args[2] = tf->tf_edx; 723 args[3] = tf->tf_esi; 724 args[4] = tf->tf_edi; 725 args[5] = tf->tf_ebp; /* Unconfirmed */ 726 *params = NULL; /* no copyin */ 727} 728 729/* 730 * If a linux binary is exec'ing something, try this image activator 731 * first. We override standard shell script execution in order to 732 * be able to modify the interpreter path. We only do this if a linux 733 * binary is doing the exec, so we do not create an EXEC module for it. 734 */ 735static int exec_linux_imgact_try(struct image_params *iparams); 736 737static int 738exec_linux_imgact_try(struct image_params *imgp) 739{ 740 const char *head = (const char *)imgp->image_header; 741 char *rpath; 742 int error = -1, len; 743 744 /* 745 * The interpreter for shell scripts run from a linux binary needs 746 * to be located in /compat/linux if possible in order to recursively 747 * maintain linux path emulation. 748 */ 749 if (((const short *)head)[0] == SHELLMAGIC) { 750 /* 751 * Run our normal shell image activator. If it succeeds attempt 752 * to use the alternate path for the interpreter. If an alternate 753 * path is found, use our stringspace to store it. 754 */ 755 if ((error = exec_shell_imgact(imgp)) == 0) { 756 linux_emul_convpath(FIRST_THREAD_IN_PROC(imgp->proc), 757 imgp->interpreter_name, UIO_SYSSPACE, &rpath, 0); 758 if (rpath != NULL) { 759 len = strlen(rpath) + 1; 760 761 if (len <= MAXSHELLCMDLEN) { 762 memcpy(imgp->interpreter_name, rpath, len); 763 } 764 free(rpath, M_TEMP); 765 } 766 } 767 } 768 return(error); 769} 770 771/* 772 * exec_setregs may initialize some registers differently than Linux 773 * does, thus potentially confusing Linux binaries. If necessary, we 774 * override the exec_setregs default(s) here. 775 */ 776static void 777exec_linux_setregs(struct thread *td, u_long entry, 778 u_long stack, u_long ps_strings) 779{ 780 static const u_short control = __LINUX_NPXCW__; 781 struct pcb *pcb = td->td_pcb; 782 783 exec_setregs(td, entry, stack, ps_strings); 784 785 /* Linux sets %gs to 0, we default to _udatasel */ 786 pcb->pcb_gs = 0; load_gs(0); 787 788 /* Linux sets the i387 to extended precision. */ 789 fldcw(&control); 790} 791 792struct sysentvec linux_sysvec = { 793 LINUX_SYS_MAXSYSCALL, 794 linux_sysent, 795 0xff, 796 LINUX_SIGTBLSZ, 797 bsd_to_linux_signal, 798 ELAST + 1, 799 bsd_to_linux_errno, 800 translate_traps, 801 linux_fixup, 802 linux_sendsig, 803 linux_sigcode, 804 &linux_szsigcode, 805 linux_prepsyscall, 806 "Linux a.out", 807 NULL, 808 exec_linux_imgact_try, 809 LINUX_MINSIGSTKSZ, 810 PAGE_SIZE, 811 VM_MIN_ADDRESS, 812 VM_MAXUSER_ADDRESS, 813 USRSTACK, 814 PS_STRINGS, 815 VM_PROT_ALL, 816 exec_copyout_strings, 817 exec_linux_setregs, 818 NULL 819}; 820 821struct sysentvec elf_linux_sysvec = { 822 LINUX_SYS_MAXSYSCALL, 823 linux_sysent, 824 0xff, 825 LINUX_SIGTBLSZ, 826 bsd_to_linux_signal, 827 ELAST + 1, 828 bsd_to_linux_errno, 829 translate_traps, 830 elf_linux_fixup, 831 linux_sendsig, 832 linux_sigcode, 833 &linux_szsigcode, 834 linux_prepsyscall, 835 "Linux ELF", 836 elf32_coredump, 837 exec_linux_imgact_try, 838 LINUX_MINSIGSTKSZ, 839 PAGE_SIZE, 840 VM_MIN_ADDRESS, 841 VM_MAXUSER_ADDRESS, 842 USRSTACK, 843 PS_STRINGS, 844 VM_PROT_ALL, 845 exec_copyout_strings, 846 exec_linux_setregs, 847 NULL 848}; 849 850static Elf32_Brandinfo linux_brand = { 851 ELFOSABI_LINUX, 852 EM_386, 853 "Linux", 854 "/compat/linux", 855 "/lib/ld-linux.so.1", 856 &elf_linux_sysvec, 857 NULL, 858 }; 859 860static Elf32_Brandinfo linux_glibc2brand = { 861 ELFOSABI_LINUX, 862 EM_386, 863 "Linux", 864 "/compat/linux", 865 "/lib/ld-linux.so.2", 866 &elf_linux_sysvec, 867 NULL, 868 }; 869 870Elf32_Brandinfo *linux_brandlist[] = { 871 &linux_brand, 872 &linux_glibc2brand, 873 NULL 874 }; 875 876static int 877linux_elf_modevent(module_t mod, int type, void *data) 878{ 879 Elf32_Brandinfo **brandinfo; 880 int error; 881 struct linux_ioctl_handler **lihp; 882 883 error = 0; 884 885 switch(type) { 886 case MOD_LOAD: 887 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 888 ++brandinfo) 889 if (elf32_insert_brand_entry(*brandinfo) < 0) 890 error = EINVAL; 891 if (error == 0) { 892 SET_FOREACH(lihp, linux_ioctl_handler_set) 893 linux_ioctl_register_handler(*lihp); 894 if (bootverbose) 895 printf("Linux ELF exec handler installed\n"); 896 } else 897 printf("cannot insert Linux ELF brand handler\n"); 898 break; 899 case MOD_UNLOAD: 900 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 901 ++brandinfo) 902 if (elf32_brand_inuse(*brandinfo)) 903 error = EBUSY; 904 if (error == 0) { 905 for (brandinfo = &linux_brandlist[0]; 906 *brandinfo != NULL; ++brandinfo) 907 if (elf32_remove_brand_entry(*brandinfo) < 0) 908 error = EINVAL; 909 } 910 if (error == 0) { 911 SET_FOREACH(lihp, linux_ioctl_handler_set) 912 linux_ioctl_unregister_handler(*lihp); 913 if (bootverbose) 914 printf("Linux ELF exec handler removed\n"); 915 linux_mib_destroy(); 916 } else 917 printf("Could not deinstall ELF interpreter entry\n"); 918 break; 919 default: 920 return EOPNOTSUPP; 921 } 922 return error; 923} 924 925static moduledata_t linux_elf_mod = { 926 "linuxelf", 927 linux_elf_modevent, 928 0 929}; 930 931DECLARE_MODULE(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY); 932