1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2004 Tim J. Robbins
5 * Copyright (c) 2003 Peter Wemm
6 * Copyright (c) 2002 Doug Rabson
7 * Copyright (c) 1998-1999 Andrew Gallatin
8 * Copyright (c) 1994-1996 Søren Schmidt
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer
16 * in this position and unchanged.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. The name of the author may not be used to endorse or promote products
21 * derived from this software without specific prior written permission
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35 #include <sys/cdefs.h>
36 #ifndef COMPAT_FREEBSD32
37 #error "Unable to compile Linux-emulator due to missing COMPAT_FREEBSD32 option!"
38 #endif
39
40 #define __ELF_WORD_SIZE 32
41
42 #include <sys/param.h>
43 #include <sys/exec.h>
44 #include <sys/fcntl.h>
45 #include <sys/imgact.h>
46 #include <sys/imgact_elf.h>
47 #include <sys/kernel.h>
48 #include <sys/lock.h>
49 #include <sys/malloc.h>
50 #include <sys/module.h>
51 #include <sys/mutex.h>
52 #include <sys/proc.h>
53 #include <sys/stddef.h>
54 #include <sys/syscallsubr.h>
55 #include <sys/sysctl.h>
56 #include <sys/sysent.h>
57
58 #include <vm/pmap.h>
59 #include <vm/vm.h>
60 #include <vm/vm_map.h>
61 #include <vm/vm_page.h>
62
63 #include <machine/cpu.h>
64 #include <machine/md_var.h>
65 #include <machine/pcb.h>
66 #include <machine/specialreg.h>
67 #include <machine/trap.h>
68
69 #include <x86/linux/linux_x86.h>
70 #include <amd64/linux32/linux.h>
71 #include <amd64/linux32/linux32_proto.h>
72 #include <compat/linux/linux_elf.h>
73 #include <compat/linux/linux_emul.h>
74 #include <compat/linux/linux_fork.h>
75 #include <compat/linux/linux_ioctl.h>
76 #include <compat/linux/linux_mib.h>
77 #include <compat/linux/linux_misc.h>
78 #include <compat/linux/linux_signal.h>
79 #include <compat/linux/linux_util.h>
80 #include <compat/linux/linux_vdso.h>
81
82 #include <x86/linux/linux_x86_sigframe.h>
83
84 MODULE_VERSION(linux, 1);
85
86 #define LINUX32_MAXUSER ((1ul << 32) - PAGE_SIZE)
87 #define LINUX32_VDSOPAGE_SIZE PAGE_SIZE * 2
88 #define LINUX32_VDSOPAGE (LINUX32_MAXUSER - LINUX32_VDSOPAGE_SIZE)
89 #define LINUX32_SHAREDPAGE (LINUX32_VDSOPAGE - PAGE_SIZE)
90 /*
91 * PAGE_SIZE - the size
92 * of the native SHAREDPAGE
93 */
94 #define LINUX32_USRSTACK LINUX32_SHAREDPAGE
95
96 static int linux_szsigcode;
97 static vm_object_t linux_vdso_obj;
98 static char *linux_vdso_mapping;
99 extern char _binary_linux32_vdso_so_o_start;
100 extern char _binary_linux32_vdso_so_o_end;
101 static vm_offset_t linux_vdso_base;
102
103 extern struct sysent linux32_sysent[LINUX32_SYS_MAXSYSCALL];
104 extern const char *linux32_syscallnames[];
105
106 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);
107
108 static int linux_copyout_strings(struct image_params *imgp,
109 uintptr_t *stack_base);
110 static void linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask);
111 static void linux_exec_setregs(struct thread *td,
112 struct image_params *imgp, uintptr_t stack);
113 static void linux_exec_sysvec_init(void *param);
114 static int linux_on_exec_vmspace(struct proc *p,
115 struct image_params *imgp);
116 static void linux32_fixlimit(struct rlimit *rl, int which);
117 static void linux_vdso_install(const void *param);
118 static void linux_vdso_deinstall(const void *param);
119 static void linux_vdso_reloc(char *mapping, Elf_Addr offset);
120 static void linux32_set_fork_retval(struct thread *td);
121 static void linux32_set_syscall_retval(struct thread *td, int error);
122
123 struct linux32_ps_strings {
124 u_int32_t ps_argvstr; /* first of 0 or more argument strings */
125 u_int ps_nargvstr; /* the number of argument strings */
126 u_int32_t ps_envstr; /* first of 0 or more environment strings */
127 u_int ps_nenvstr; /* the number of environment strings */
128 };
129 #define LINUX32_PS_STRINGS (LINUX32_USRSTACK - \
130 sizeof(struct linux32_ps_strings))
131
132 LINUX_VDSO_SYM_INTPTR(__kernel_vsyscall);
133 LINUX_VDSO_SYM_INTPTR(linux32_vdso_sigcode);
134 LINUX_VDSO_SYM_INTPTR(linux32_vdso_rt_sigcode);
135 LINUX_VDSO_SYM_INTPTR(kern_timekeep_base);
136 LINUX_VDSO_SYM_INTPTR(kern_tsc_selector);
137 LINUX_VDSO_SYM_INTPTR(kern_cpu_selector);
138 LINUX_VDSO_SYM_CHAR(linux_platform);
139
140 void
linux32_arch_copyout_auxargs(struct image_params * imgp,Elf_Auxinfo ** pos)141 linux32_arch_copyout_auxargs(struct image_params *imgp, Elf_Auxinfo **pos)
142 {
143
144 AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO, __kernel_vsyscall);
145 AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO_EHDR, linux_vdso_base);
146 AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP, cpu_feature);
147 AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP2, linux_x86_elf_hwcap2());
148 AUXARGS_ENTRY((*pos), LINUX_AT_PLATFORM, PTROUT(linux_platform));
149 }
150
151 static void
linux_rt_sendsig(sig_t catcher,ksiginfo_t * ksi,sigset_t * mask)152 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
153 {
154 struct thread *td = curthread;
155 struct proc *p = td->td_proc;
156 struct sigacts *psp;
157 struct trapframe *regs;
158 struct l_rt_sigframe *fp, frame;
159 int oonstack;
160 int sig;
161 int code;
162
163 sig = linux_translate_traps(ksi->ksi_signo, ksi->ksi_trapno);
164 code = ksi->ksi_code;
165 PROC_LOCK_ASSERT(p, MA_OWNED);
166 psp = p->p_sigacts;
167 mtx_assert(&psp->ps_mtx, MA_OWNED);
168 regs = td->td_frame;
169 oonstack = sigonstack(regs->tf_rsp);
170
171 /* Allocate space for the signal handler context. */
172 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack &&
173 SIGISMEMBER(psp->ps_sigonstack, sig)) {
174 fp = (struct l_rt_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
175 td->td_sigstk.ss_size - sizeof(struct l_rt_sigframe));
176 } else
177 fp = (struct l_rt_sigframe *)regs->tf_rsp - 1;
178 mtx_unlock(&psp->ps_mtx);
179
180 /* Build the argument list for the signal handler. */
181 sig = bsd_to_linux_signal(sig);
182
183 bzero(&frame, sizeof(frame));
184
185 frame.sf_sig = sig;
186 frame.sf_siginfo = PTROUT(&fp->sf_si);
187 frame.sf_ucontext = PTROUT(&fp->sf_uc);
188
189 /* Fill in POSIX parts. */
190 siginfo_to_lsiginfo(&ksi->ksi_info, &frame.sf_si, sig);
191
192 /*
193 * Build the signal context to be used by sigreturn and libgcc unwind.
194 */
195 frame.sf_uc.uc_stack.ss_sp = PTROUT(td->td_sigstk.ss_sp);
196 frame.sf_uc.uc_stack.ss_size = td->td_sigstk.ss_size;
197 frame.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
198 ? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE;
199 PROC_UNLOCK(p);
200
201 bsd_to_linux_sigset(mask, &frame.sf_uc.uc_sigmask);
202
203 frame.sf_uc.uc_mcontext.sc_mask = frame.sf_uc.uc_sigmask.__mask;
204 frame.sf_uc.uc_mcontext.sc_edi = regs->tf_rdi;
205 frame.sf_uc.uc_mcontext.sc_esi = regs->tf_rsi;
206 frame.sf_uc.uc_mcontext.sc_ebp = regs->tf_rbp;
207 frame.sf_uc.uc_mcontext.sc_ebx = regs->tf_rbx;
208 frame.sf_uc.uc_mcontext.sc_esp = regs->tf_rsp;
209 frame.sf_uc.uc_mcontext.sc_edx = regs->tf_rdx;
210 frame.sf_uc.uc_mcontext.sc_ecx = regs->tf_rcx;
211 frame.sf_uc.uc_mcontext.sc_eax = regs->tf_rax;
212 frame.sf_uc.uc_mcontext.sc_eip = regs->tf_rip;
213 frame.sf_uc.uc_mcontext.sc_cs = regs->tf_cs;
214 frame.sf_uc.uc_mcontext.sc_gs = regs->tf_gs;
215 frame.sf_uc.uc_mcontext.sc_fs = regs->tf_fs;
216 frame.sf_uc.uc_mcontext.sc_es = regs->tf_es;
217 frame.sf_uc.uc_mcontext.sc_ds = regs->tf_ds;
218 frame.sf_uc.uc_mcontext.sc_eflags = regs->tf_rflags;
219 frame.sf_uc.uc_mcontext.sc_esp_at_signal = regs->tf_rsp;
220 frame.sf_uc.uc_mcontext.sc_ss = regs->tf_ss;
221 frame.sf_uc.uc_mcontext.sc_err = regs->tf_err;
222 frame.sf_uc.uc_mcontext.sc_cr2 = (u_int32_t)(uintptr_t)ksi->ksi_addr;
223 frame.sf_uc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code);
224
225 if (copyout(&frame, fp, sizeof(frame)) != 0) {
226 /*
227 * Process has trashed its stack; give it an illegal
228 * instruction to halt it in its tracks.
229 */
230 PROC_LOCK(p);
231 sigexit(td, SIGILL);
232 }
233
234 /* Build context to run handler in. */
235 regs->tf_rsp = PTROUT(fp);
236 regs->tf_rip = linux32_vdso_rt_sigcode;
237 regs->tf_rdi = PTROUT(catcher);
238 regs->tf_rflags &= ~(PSL_T | PSL_D);
239 regs->tf_cs = _ucode32sel;
240 regs->tf_ss = _udatasel;
241 regs->tf_ds = _udatasel;
242 regs->tf_es = _udatasel;
243 regs->tf_fs = _ufssel;
244 regs->tf_gs = _ugssel;
245 regs->tf_flags = TF_HASSEGS;
246 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
247 PROC_LOCK(p);
248 mtx_lock(&psp->ps_mtx);
249 }
250
251 /*
252 * Send an interrupt to process.
253 *
254 * Stack is set up to allow sigcode stored
255 * in u. to call routine, followed by kcall
256 * to sigreturn routine below. After sigreturn
257 * resets the signal mask, the stack, and the
258 * frame pointer, it returns to the user
259 * specified pc, psl.
260 */
261 static void
linux_sendsig(sig_t catcher,ksiginfo_t * ksi,sigset_t * mask)262 linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
263 {
264 struct thread *td = curthread;
265 struct proc *p = td->td_proc;
266 struct sigacts *psp;
267 struct trapframe *regs;
268 struct l_sigframe *fp, frame;
269 l_sigset_t lmask;
270 int oonstack;
271 int sig, code;
272
273 sig = linux_translate_traps(ksi->ksi_signo, ksi->ksi_trapno);
274 code = ksi->ksi_code;
275 PROC_LOCK_ASSERT(p, MA_OWNED);
276 psp = p->p_sigacts;
277 mtx_assert(&psp->ps_mtx, MA_OWNED);
278 if (SIGISMEMBER(psp->ps_siginfo, sig)) {
279 /* Signal handler installed with SA_SIGINFO. */
280 linux_rt_sendsig(catcher, ksi, mask);
281 return;
282 }
283
284 regs = td->td_frame;
285 oonstack = sigonstack(regs->tf_rsp);
286
287 /* Allocate space for the signal handler context. */
288 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack &&
289 SIGISMEMBER(psp->ps_sigonstack, sig)) {
290 fp = (struct l_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
291 td->td_sigstk.ss_size - sizeof(struct l_sigframe));
292 } else
293 fp = (struct l_sigframe *)regs->tf_rsp - 1;
294 mtx_unlock(&psp->ps_mtx);
295 PROC_UNLOCK(p);
296
297 /* Build the argument list for the signal handler. */
298 sig = bsd_to_linux_signal(sig);
299
300 bzero(&frame, sizeof(frame));
301
302 frame.sf_sig = sig;
303 frame.sf_sigmask = *mask;
304 bsd_to_linux_sigset(mask, &lmask);
305
306 /* Build the signal context to be used by sigreturn. */
307 frame.sf_sc.sc_mask = lmask.__mask;
308 frame.sf_sc.sc_gs = regs->tf_gs;
309 frame.sf_sc.sc_fs = regs->tf_fs;
310 frame.sf_sc.sc_es = regs->tf_es;
311 frame.sf_sc.sc_ds = regs->tf_ds;
312 frame.sf_sc.sc_edi = regs->tf_rdi;
313 frame.sf_sc.sc_esi = regs->tf_rsi;
314 frame.sf_sc.sc_ebp = regs->tf_rbp;
315 frame.sf_sc.sc_ebx = regs->tf_rbx;
316 frame.sf_sc.sc_esp = regs->tf_rsp;
317 frame.sf_sc.sc_edx = regs->tf_rdx;
318 frame.sf_sc.sc_ecx = regs->tf_rcx;
319 frame.sf_sc.sc_eax = regs->tf_rax;
320 frame.sf_sc.sc_eip = regs->tf_rip;
321 frame.sf_sc.sc_cs = regs->tf_cs;
322 frame.sf_sc.sc_eflags = regs->tf_rflags;
323 frame.sf_sc.sc_esp_at_signal = regs->tf_rsp;
324 frame.sf_sc.sc_ss = regs->tf_ss;
325 frame.sf_sc.sc_err = regs->tf_err;
326 frame.sf_sc.sc_cr2 = (u_int32_t)(uintptr_t)ksi->ksi_addr;
327 frame.sf_sc.sc_trapno = bsd_to_linux_trapcode(code);
328
329 if (copyout(&frame, fp, sizeof(frame)) != 0) {
330 /*
331 * Process has trashed its stack; give it an illegal
332 * instruction to halt it in its tracks.
333 */
334 PROC_LOCK(p);
335 sigexit(td, SIGILL);
336 }
337
338 /* Build context to run handler in. */
339 regs->tf_rsp = PTROUT(fp);
340 regs->tf_rip = linux32_vdso_sigcode;
341 regs->tf_rdi = PTROUT(catcher);
342 regs->tf_rflags &= ~(PSL_T | PSL_D);
343 regs->tf_cs = _ucode32sel;
344 regs->tf_ss = _udatasel;
345 regs->tf_ds = _udatasel;
346 regs->tf_es = _udatasel;
347 regs->tf_fs = _ufssel;
348 regs->tf_gs = _ugssel;
349 regs->tf_flags = TF_HASSEGS;
350 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
351 PROC_LOCK(p);
352 mtx_lock(&psp->ps_mtx);
353 }
354
355 /*
356 * System call to cleanup state after a signal
357 * has been taken. Reset signal mask and
358 * stack state from context left by sendsig (above).
359 * Return to previous pc and psl as specified by
360 * context left by sendsig. Check carefully to
361 * make sure that the user has not modified the
362 * psl to gain improper privileges or to cause
363 * a machine fault.
364 */
365 int
linux_sigreturn(struct thread * td,struct linux_sigreturn_args * args)366 linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
367 {
368 struct l_sigframe frame;
369 struct trapframe *regs;
370 int eflags;
371 ksiginfo_t ksi;
372
373 regs = td->td_frame;
374
375 /*
376 * The trampoline code hands us the sigframe.
377 * It is unsafe to keep track of it ourselves, in the event that a
378 * program jumps out of a signal handler.
379 */
380 if (copyin(args->sfp, &frame, sizeof(frame)) != 0)
381 return (EFAULT);
382
383 /* Check for security violations. */
384 eflags = frame.sf_sc.sc_eflags;
385 if (!EFL_SECURE(eflags, regs->tf_rflags))
386 return(EINVAL);
387
388 /*
389 * Don't allow users to load a valid privileged %cs. Let the
390 * hardware check for invalid selectors, excess privilege in
391 * other selectors, invalid %eip's and invalid %esp's.
392 */
393 if (!CS_SECURE(frame.sf_sc.sc_cs)) {
394 ksiginfo_init_trap(&ksi);
395 ksi.ksi_signo = SIGBUS;
396 ksi.ksi_code = BUS_OBJERR;
397 ksi.ksi_trapno = T_PROTFLT;
398 ksi.ksi_addr = (void *)regs->tf_rip;
399 trapsignal(td, &ksi);
400 return(EINVAL);
401 }
402
403 kern_sigprocmask(td, SIG_SETMASK, &frame.sf_sigmask, NULL, 0);
404
405 /* Restore signal context. */
406 regs->tf_rdi = frame.sf_sc.sc_edi;
407 regs->tf_rsi = frame.sf_sc.sc_esi;
408 regs->tf_rbp = frame.sf_sc.sc_ebp;
409 regs->tf_rbx = frame.sf_sc.sc_ebx;
410 regs->tf_rdx = frame.sf_sc.sc_edx;
411 regs->tf_rcx = frame.sf_sc.sc_ecx;
412 regs->tf_rax = frame.sf_sc.sc_eax;
413 regs->tf_rip = frame.sf_sc.sc_eip;
414 regs->tf_cs = frame.sf_sc.sc_cs;
415 regs->tf_ds = frame.sf_sc.sc_ds;
416 regs->tf_es = frame.sf_sc.sc_es;
417 regs->tf_fs = frame.sf_sc.sc_fs;
418 regs->tf_gs = frame.sf_sc.sc_gs;
419 regs->tf_rflags = eflags;
420 regs->tf_rsp = frame.sf_sc.sc_esp_at_signal;
421 regs->tf_ss = frame.sf_sc.sc_ss;
422 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
423
424 return (EJUSTRETURN);
425 }
426
427 /*
428 * System call to cleanup state after a signal
429 * has been taken. Reset signal mask and
430 * stack state from context left by rt_sendsig (above).
431 * Return to previous pc and psl as specified by
432 * context left by sendsig. Check carefully to
433 * make sure that the user has not modified the
434 * psl to gain improper privileges or to cause
435 * a machine fault.
436 */
437 int
linux_rt_sigreturn(struct thread * td,struct linux_rt_sigreturn_args * args)438 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
439 {
440 struct l_ucontext uc;
441 struct l_sigcontext *context;
442 sigset_t bmask;
443 l_stack_t *lss;
444 stack_t ss;
445 struct trapframe *regs;
446 int eflags;
447 ksiginfo_t ksi;
448
449 regs = td->td_frame;
450
451 /*
452 * The trampoline code hands us the ucontext.
453 * It is unsafe to keep track of it ourselves, in the event that a
454 * program jumps out of a signal handler.
455 */
456 if (copyin(args->ucp, &uc, sizeof(uc)) != 0)
457 return (EFAULT);
458
459 context = &uc.uc_mcontext;
460
461 /* Check for security violations. */
462 eflags = context->sc_eflags;
463 if (!EFL_SECURE(eflags, regs->tf_rflags))
464 return(EINVAL);
465
466 /*
467 * Don't allow users to load a valid privileged %cs. Let the
468 * hardware check for invalid selectors, excess privilege in
469 * other selectors, invalid %eip's and invalid %esp's.
470 */
471 if (!CS_SECURE(context->sc_cs)) {
472 ksiginfo_init_trap(&ksi);
473 ksi.ksi_signo = SIGBUS;
474 ksi.ksi_code = BUS_OBJERR;
475 ksi.ksi_trapno = T_PROTFLT;
476 ksi.ksi_addr = (void *)regs->tf_rip;
477 trapsignal(td, &ksi);
478 return(EINVAL);
479 }
480
481 linux_to_bsd_sigset(&uc.uc_sigmask, &bmask);
482 kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
483
484 /*
485 * Restore signal context
486 */
487 regs->tf_gs = context->sc_gs;
488 regs->tf_fs = context->sc_fs;
489 regs->tf_es = context->sc_es;
490 regs->tf_ds = context->sc_ds;
491 regs->tf_rdi = context->sc_edi;
492 regs->tf_rsi = context->sc_esi;
493 regs->tf_rbp = context->sc_ebp;
494 regs->tf_rbx = context->sc_ebx;
495 regs->tf_rdx = context->sc_edx;
496 regs->tf_rcx = context->sc_ecx;
497 regs->tf_rax = context->sc_eax;
498 regs->tf_rip = context->sc_eip;
499 regs->tf_cs = context->sc_cs;
500 regs->tf_rflags = eflags;
501 regs->tf_rsp = context->sc_esp_at_signal;
502 regs->tf_ss = context->sc_ss;
503 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
504
505 /*
506 * call sigaltstack & ignore results..
507 */
508 lss = &uc.uc_stack;
509 ss.ss_sp = PTRIN(lss->ss_sp);
510 ss.ss_size = lss->ss_size;
511 ss.ss_flags = linux_to_bsd_sigaltstack(lss->ss_flags);
512
513 (void)kern_sigaltstack(td, &ss, NULL);
514
515 return (EJUSTRETURN);
516 }
517
518 static int
linux32_fetch_syscall_args(struct thread * td)519 linux32_fetch_syscall_args(struct thread *td)
520 {
521 struct proc *p;
522 struct trapframe *frame;
523 struct syscall_args *sa;
524
525 p = td->td_proc;
526 frame = td->td_frame;
527 sa = &td->td_sa;
528
529 sa->args[0] = frame->tf_rbx;
530 sa->args[1] = frame->tf_rcx;
531 sa->args[2] = frame->tf_rdx;
532 sa->args[3] = frame->tf_rsi;
533 sa->args[4] = frame->tf_rdi;
534 sa->args[5] = frame->tf_rbp; /* Unconfirmed */
535 sa->code = frame->tf_rax;
536
537 if (sa->code >= p->p_sysent->sv_size)
538 /* nosys */
539 sa->callp = &nosys_sysent;
540 else
541 sa->callp = &p->p_sysent->sv_table[sa->code];
542
543 td->td_retval[0] = 0;
544 td->td_retval[1] = frame->tf_rdx;
545
546 return (0);
547 }
548
549 static void
linux32_set_syscall_retval(struct thread * td,int error)550 linux32_set_syscall_retval(struct thread *td, int error)
551 {
552 struct trapframe *frame = td->td_frame;
553
554 cpu_set_syscall_retval(td, error);
555
556 if (__predict_false(error != 0)) {
557 if (error != ERESTART && error != EJUSTRETURN)
558 frame->tf_rax = bsd_to_linux_errno(error);
559 }
560 }
561
562 static void
linux32_set_fork_retval(struct thread * td)563 linux32_set_fork_retval(struct thread *td)
564 {
565 struct trapframe *frame = td->td_frame;
566
567 frame->tf_rax = 0;
568 }
569
570 /*
571 * Clear registers on exec
572 * XXX copied from ia32_signal.c.
573 */
574 static void
linux_exec_setregs(struct thread * td,struct image_params * imgp,uintptr_t stack)575 linux_exec_setregs(struct thread *td, struct image_params *imgp,
576 uintptr_t stack)
577 {
578 struct trapframe *regs = td->td_frame;
579 struct pcb *pcb = td->td_pcb;
580 register_t saved_rflags;
581
582 regs = td->td_frame;
583 pcb = td->td_pcb;
584
585 if (td->td_proc->p_md.md_ldt != NULL)
586 user_ldt_free(td);
587
588 critical_enter();
589 wrmsr(MSR_FSBASE, 0);
590 wrmsr(MSR_KGSBASE, 0); /* User value while we're in the kernel */
591 pcb->pcb_fsbase = 0;
592 pcb->pcb_gsbase = 0;
593 critical_exit();
594 pcb->pcb_initial_fpucw = __LINUX_NPXCW__;
595
596 saved_rflags = regs->tf_rflags & PSL_T;
597 bzero((char *)regs, sizeof(struct trapframe));
598 regs->tf_rip = imgp->entry_addr;
599 regs->tf_rsp = stack;
600 regs->tf_rflags = PSL_USER | saved_rflags;
601 regs->tf_gs = _ugssel;
602 regs->tf_fs = _ufssel;
603 regs->tf_es = _udatasel;
604 regs->tf_ds = _udatasel;
605 regs->tf_ss = _udatasel;
606 regs->tf_flags = TF_HASSEGS;
607 regs->tf_cs = _ucode32sel;
608 regs->tf_rbx = (register_t)imgp->ps_strings;
609
610 x86_clear_dbregs(pcb);
611
612 fpstate_drop(td);
613
614 /* Do full restore on return so that we can change to a different %cs */
615 set_pcb_flags(pcb, PCB_32BIT | PCB_FULL_IRET);
616 }
617
618 /*
619 * XXX copied from ia32_sysvec.c.
620 */
621 static int
linux_copyout_strings(struct image_params * imgp,uintptr_t * stack_base)622 linux_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
623 {
624 int argc, envc, error;
625 u_int32_t *vectp;
626 char *stringp;
627 uintptr_t destp, ustringp;
628 struct linux32_ps_strings *arginfo;
629 char canary[LINUX_AT_RANDOM_LEN];
630 size_t execpath_len;
631
632 arginfo = (struct linux32_ps_strings *)PROC_PS_STRINGS(imgp->proc);
633 destp = (uintptr_t)arginfo;
634
635 if (imgp->execpath != NULL && imgp->auxargs != NULL) {
636 execpath_len = strlen(imgp->execpath) + 1;
637 destp -= execpath_len;
638 destp = rounddown2(destp, sizeof(uint32_t));
639 imgp->execpathp = (void *)destp;
640 error = copyout(imgp->execpath, imgp->execpathp, execpath_len);
641 if (error != 0)
642 return (error);
643 }
644
645 /* Prepare the canary for SSP. */
646 arc4rand(canary, sizeof(canary), 0);
647 destp -= roundup(sizeof(canary), sizeof(uint32_t));
648 imgp->canary = (void *)destp;
649 error = copyout(canary, imgp->canary, sizeof(canary));
650 if (error != 0)
651 return (error);
652
653 /* Allocate room for the argument and environment strings. */
654 destp -= ARG_MAX - imgp->args->stringspace;
655 destp = rounddown2(destp, sizeof(uint32_t));
656 ustringp = destp;
657
658 if (imgp->auxargs) {
659 /*
660 * Allocate room on the stack for the ELF auxargs
661 * array. It has LINUX_AT_COUNT entries.
662 */
663 destp -= LINUX_AT_COUNT * sizeof(Elf32_Auxinfo);
664 destp = rounddown2(destp, sizeof(uint32_t));
665 }
666
667 vectp = (uint32_t *)destp;
668
669 /*
670 * Allocate room for the argv[] and env vectors including the
671 * terminating NULL pointers.
672 */
673 vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
674
675 /* vectp also becomes our initial stack base. */
676 *stack_base = (uintptr_t)vectp;
677
678 stringp = imgp->args->begin_argv;
679 argc = imgp->args->argc;
680 envc = imgp->args->envc;
681
682 /* Copy out strings - arguments and environment. */
683 error = copyout(stringp, (void *)ustringp,
684 ARG_MAX - imgp->args->stringspace);
685 if (error != 0)
686 return (error);
687
688 /* Fill in "ps_strings" struct for ps, w, etc. */
689 if (suword32(&arginfo->ps_argvstr, (uint32_t)(intptr_t)vectp) != 0 ||
690 suword32(&arginfo->ps_nargvstr, argc) != 0)
691 return (EFAULT);
692
693 /* Fill in argument portion of vector table. */
694 for (; argc > 0; --argc) {
695 if (suword32(vectp++, ustringp) != 0)
696 return (EFAULT);
697 while (*stringp++ != 0)
698 ustringp++;
699 ustringp++;
700 }
701
702 /* A null vector table pointer separates the argp's from the envp's. */
703 if (suword32(vectp++, 0) != 0)
704 return (EFAULT);
705
706 if (suword32(&arginfo->ps_envstr, (uint32_t)(intptr_t)vectp) != 0 ||
707 suword32(&arginfo->ps_nenvstr, envc) != 0)
708 return (EFAULT);
709
710 /* Fill in environment portion of vector table. */
711 for (; envc > 0; --envc) {
712 if (suword32(vectp++, ustringp) != 0)
713 return (EFAULT);
714 while (*stringp++ != 0)
715 ustringp++;
716 ustringp++;
717 }
718
719 /* The end of the vector table is a null pointer. */
720 if (suword32(vectp, 0) != 0)
721 return (EFAULT);
722
723 if (imgp->auxargs) {
724 vectp++;
725 error = imgp->sysent->sv_copyout_auxargs(imgp,
726 (uintptr_t)vectp);
727 if (error != 0)
728 return (error);
729 }
730
731 return (0);
732 }
733
734 static SYSCTL_NODE(_compat, OID_AUTO, linux32, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
735 "32-bit Linux emulation");
736
737 static u_long linux32_maxdsiz = LINUX32_MAXDSIZ;
738 SYSCTL_ULONG(_compat_linux32, OID_AUTO, maxdsiz, CTLFLAG_RW,
739 &linux32_maxdsiz, 0, "");
740 static u_long linux32_maxssiz = LINUX32_MAXSSIZ;
741 SYSCTL_ULONG(_compat_linux32, OID_AUTO, maxssiz, CTLFLAG_RW,
742 &linux32_maxssiz, 0, "");
743 static u_long linux32_maxvmem = LINUX32_MAXVMEM;
744 SYSCTL_ULONG(_compat_linux32, OID_AUTO, maxvmem, CTLFLAG_RW,
745 &linux32_maxvmem, 0, "");
746 bool linux32_emulate_i386 = false;
747 SYSCTL_BOOL(_compat_linux32, OID_AUTO, emulate_i386, CTLFLAG_RWTUN,
748 &linux32_emulate_i386, 0, "Emulate the real i386");
749
750 static void
linux32_fixlimit(struct rlimit * rl,int which)751 linux32_fixlimit(struct rlimit *rl, int which)
752 {
753
754 switch (which) {
755 case RLIMIT_DATA:
756 if (linux32_maxdsiz != 0) {
757 if (rl->rlim_cur > linux32_maxdsiz)
758 rl->rlim_cur = linux32_maxdsiz;
759 if (rl->rlim_max > linux32_maxdsiz)
760 rl->rlim_max = linux32_maxdsiz;
761 }
762 break;
763 case RLIMIT_STACK:
764 if (linux32_maxssiz != 0) {
765 if (rl->rlim_cur > linux32_maxssiz)
766 rl->rlim_cur = linux32_maxssiz;
767 if (rl->rlim_max > linux32_maxssiz)
768 rl->rlim_max = linux32_maxssiz;
769 }
770 break;
771 case RLIMIT_VMEM:
772 if (linux32_maxvmem != 0) {
773 if (rl->rlim_cur > linux32_maxvmem)
774 rl->rlim_cur = linux32_maxvmem;
775 if (rl->rlim_max > linux32_maxvmem)
776 rl->rlim_max = linux32_maxvmem;
777 }
778 break;
779 }
780 }
781
782 struct sysentvec elf_linux_sysvec = {
783 .sv_size = LINUX32_SYS_MAXSYSCALL,
784 .sv_table = linux32_sysent,
785 .sv_fixup = elf32_freebsd_fixup,
786 .sv_sendsig = linux_sendsig,
787 .sv_sigcode = &_binary_linux32_vdso_so_o_start,
788 .sv_szsigcode = &linux_szsigcode,
789 .sv_name = "Linux ELF32",
790 .sv_coredump = elf32_coredump,
791 .sv_elf_core_osabi = ELFOSABI_NONE,
792 .sv_elf_core_abi_vendor = LINUX_ABI_VENDOR,
793 .sv_elf_core_prepare_notes = linux32_prepare_notes,
794 .sv_imgact_try = linux_exec_imgact_try,
795 .sv_minsigstksz = LINUX_MINSIGSTKSZ,
796 .sv_minuser = VM_MIN_ADDRESS,
797 .sv_maxuser = LINUX32_MAXUSER,
798 .sv_usrstack = LINUX32_USRSTACK,
799 .sv_psstrings = LINUX32_PS_STRINGS,
800 .sv_psstringssz = sizeof(struct linux32_ps_strings),
801 .sv_stackprot = VM_PROT_ALL,
802 .sv_copyout_auxargs = __linuxN(copyout_auxargs),
803 .sv_copyout_strings = linux_copyout_strings,
804 .sv_setregs = linux_exec_setregs,
805 .sv_fixlimit = linux32_fixlimit,
806 .sv_maxssiz = &linux32_maxssiz,
807 .sv_flags = SV_ABI_LINUX | SV_ILP32 | SV_IA32 | SV_SHP |
808 SV_SIG_DISCIGN | SV_SIG_WAITNDQ | SV_TIMEKEEP,
809 .sv_set_syscall_retval = linux32_set_syscall_retval,
810 .sv_fetch_syscall_args = linux32_fetch_syscall_args,
811 .sv_syscallnames = linux32_syscallnames,
812 .sv_shared_page_base = LINUX32_SHAREDPAGE,
813 .sv_shared_page_len = PAGE_SIZE,
814 .sv_schedtail = linux_schedtail,
815 .sv_thread_detach = linux_thread_detach,
816 .sv_trap = NULL,
817 .sv_hwcap = NULL,
818 .sv_hwcap2 = NULL,
819 .sv_onexec = linux_on_exec_vmspace,
820 .sv_onexit = linux_on_exit,
821 .sv_ontdexit = linux_thread_dtor,
822 .sv_setid_allowed = &linux_setid_allowed_query,
823 .sv_set_fork_retval = linux32_set_fork_retval,
824 };
825
826 static int
linux_on_exec_vmspace(struct proc * p,struct image_params * imgp)827 linux_on_exec_vmspace(struct proc *p, struct image_params *imgp)
828 {
829 int error;
830
831 error = linux_map_vdso(p, linux_vdso_obj, linux_vdso_base,
832 LINUX32_VDSOPAGE_SIZE, imgp);
833 if (error == 0)
834 linux_on_exec(p, imgp);
835 return (error);
836 }
837
838 /*
839 * linux_vdso_install() and linux_exec_sysvec_init() must be called
840 * after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY).
841 */
842 static void
linux_exec_sysvec_init(void * param)843 linux_exec_sysvec_init(void *param)
844 {
845 l_uintptr_t *ktimekeep_base, *ktsc_selector;
846 struct sysentvec *sv;
847 ptrdiff_t tkoff;
848
849 sv = param;
850 /* Fill timekeep_base */
851 exec_sysvec_init(sv);
852
853 tkoff = kern_timekeep_base - linux_vdso_base;
854 ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
855 *ktimekeep_base = sv->sv_timekeep_base;
856
857 tkoff = kern_tsc_selector - linux_vdso_base;
858 ktsc_selector = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
859 *ktsc_selector = linux_vdso_tsc_selector_idx();
860 if (bootverbose)
861 printf("Linux i386 vDSO tsc_selector: %u\n", *ktsc_selector);
862
863 tkoff = kern_cpu_selector - linux_vdso_base;
864 ktsc_selector = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
865 *ktsc_selector = linux_vdso_cpu_selector_idx();
866 if (bootverbose)
867 printf("Linux i386 vDSO cpu_selector: %u\n", *ktsc_selector);
868 }
869 SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY,
870 linux_exec_sysvec_init, &elf_linux_sysvec);
871
872 static void
linux_vdso_install(const void * param)873 linux_vdso_install(const void *param)
874 {
875 char *vdso_start = &_binary_linux32_vdso_so_o_start;
876 char *vdso_end = &_binary_linux32_vdso_so_o_end;
877
878 linux_szsigcode = vdso_end - vdso_start;
879 MPASS(linux_szsigcode <= LINUX32_VDSOPAGE_SIZE);
880
881 linux_vdso_base = LINUX32_VDSOPAGE;
882
883 __elfN(linux_vdso_fixup)(vdso_start, linux_vdso_base);
884
885 linux_vdso_obj = __elfN(linux_shared_page_init)
886 (&linux_vdso_mapping, LINUX32_VDSOPAGE_SIZE);
887 bcopy(vdso_start, linux_vdso_mapping, linux_szsigcode);
888
889 linux_vdso_reloc(linux_vdso_mapping, linux_vdso_base);
890 }
891 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC + 1, SI_ORDER_FIRST,
892 linux_vdso_install, NULL);
893
894 static void
linux_vdso_deinstall(const void * param)895 linux_vdso_deinstall(const void *param)
896 {
897
898 __elfN(linux_shared_page_fini)(linux_vdso_obj,
899 linux_vdso_mapping, LINUX32_VDSOPAGE_SIZE);
900 }
901 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST,
902 linux_vdso_deinstall, NULL);
903
904 static void
linux_vdso_reloc(char * mapping,Elf_Addr offset)905 linux_vdso_reloc(char *mapping, Elf_Addr offset)
906 {
907 const Elf_Shdr *shdr;
908 const Elf_Rel *rel;
909 const Elf_Ehdr *ehdr;
910 Elf32_Addr *where;
911 Elf_Size rtype, symidx;
912 Elf32_Addr addr, addend;
913 int i, relcnt;
914
915 MPASS(offset != 0);
916
917 relcnt = 0;
918 ehdr = (const Elf_Ehdr *)mapping;
919 shdr = (const Elf_Shdr *)(mapping + ehdr->e_shoff);
920 for (i = 0; i < ehdr->e_shnum; i++)
921 {
922 switch (shdr[i].sh_type) {
923 case SHT_REL:
924 rel = (const Elf_Rel *)(mapping + shdr[i].sh_offset);
925 relcnt = shdr[i].sh_size / sizeof(*rel);
926 break;
927 case SHT_RELA:
928 printf("Linux i386 vDSO: unexpected Rela section\n");
929 break;
930 }
931 }
932
933 for (i = 0; i < relcnt; i++, rel++) {
934 where = (Elf32_Addr *)(mapping + rel->r_offset);
935 addend = *where;
936 rtype = ELF_R_TYPE(rel->r_info);
937 symidx = ELF_R_SYM(rel->r_info);
938
939 switch (rtype) {
940 case R_386_NONE: /* none */
941 break;
942
943 case R_386_RELATIVE: /* B + A */
944 addr = (Elf32_Addr)PTROUT(offset + addend);
945 if (*where != addr)
946 *where = addr;
947 break;
948
949 case R_386_IRELATIVE:
950 printf("Linux i386 vDSO: unexpected ifunc relocation, "
951 "symbol index %ld\n", (intmax_t)symidx);
952 break;
953 default:
954 printf("Linux i386 vDSO: unexpected relocation type %ld, "
955 "symbol index %ld\n", (intmax_t)rtype, (intmax_t)symidx);
956 }
957 }
958 }
959
960 static Elf_Brandnote linux32_brandnote = {
961 .hdr.n_namesz = sizeof(GNU_ABI_VENDOR),
962 .hdr.n_descsz = 16, /* XXX at least 16 */
963 .hdr.n_type = 1,
964 .vendor = GNU_ABI_VENDOR,
965 .flags = BN_TRANSLATE_OSREL,
966 .trans_osrel = linux_trans_osrel
967 };
968
969 static Elf32_Brandinfo linux_brand = {
970 .brand = ELFOSABI_LINUX,
971 .machine = EM_386,
972 .compat_3_brand = "Linux",
973 .emul_path = linux_emul_path,
974 .interp_path = "/lib/ld-linux.so.1",
975 .sysvec = &elf_linux_sysvec,
976 .interp_newpath = NULL,
977 .brand_note = &linux32_brandnote,
978 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
979 };
980
981 static Elf32_Brandinfo linux_glibc2brand = {
982 .brand = ELFOSABI_LINUX,
983 .machine = EM_386,
984 .compat_3_brand = "Linux",
985 .emul_path = linux_emul_path,
986 .interp_path = "/lib/ld-linux.so.2",
987 .sysvec = &elf_linux_sysvec,
988 .interp_newpath = NULL,
989 .brand_note = &linux32_brandnote,
990 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
991 };
992
993 static Elf32_Brandinfo linux_muslbrand = {
994 .brand = ELFOSABI_LINUX,
995 .machine = EM_386,
996 .compat_3_brand = "Linux",
997 .emul_path = linux_emul_path,
998 .interp_path = "/lib/ld-musl-i386.so.1",
999 .sysvec = &elf_linux_sysvec,
1000 .interp_newpath = NULL,
1001 .brand_note = &linux32_brandnote,
1002 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE |
1003 LINUX_BI_FUTEX_REQUEUE
1004 };
1005
1006 static Elf32_Brandinfo *linux_brandlist[] = {
1007 &linux_brand,
1008 &linux_glibc2brand,
1009 &linux_muslbrand,
1010 NULL
1011 };
1012
1013 static int
linux_elf_modevent(module_t mod,int type,void * data)1014 linux_elf_modevent(module_t mod, int type, void *data)
1015 {
1016 Elf32_Brandinfo **brandinfo;
1017 int error;
1018 struct linux_ioctl_handler **lihp;
1019
1020 error = 0;
1021
1022 switch(type) {
1023 case MOD_LOAD:
1024 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
1025 ++brandinfo)
1026 if (elf32_insert_brand_entry(*brandinfo) < 0)
1027 error = EINVAL;
1028 if (error == 0) {
1029 SET_FOREACH(lihp, linux_ioctl_handler_set)
1030 linux32_ioctl_register_handler(*lihp);
1031 stclohz = (stathz ? stathz : hz);
1032 if (bootverbose)
1033 printf("Linux i386 ELF exec handler installed\n");
1034 } else
1035 printf("cannot insert Linux i386 ELF brand handler\n");
1036 break;
1037 case MOD_UNLOAD:
1038 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
1039 ++brandinfo)
1040 if (elf32_brand_inuse(*brandinfo))
1041 error = EBUSY;
1042 if (error == 0) {
1043 for (brandinfo = &linux_brandlist[0];
1044 *brandinfo != NULL; ++brandinfo)
1045 if (elf32_remove_brand_entry(*brandinfo) < 0)
1046 error = EINVAL;
1047 }
1048 if (error == 0) {
1049 SET_FOREACH(lihp, linux_ioctl_handler_set)
1050 linux32_ioctl_unregister_handler(*lihp);
1051 if (bootverbose)
1052 printf("Linux i386 ELF exec handler removed\n");
1053 } else
1054 printf("Could not deinstall Linux i386 ELF interpreter entry\n");
1055 break;
1056 default:
1057 return (EOPNOTSUPP);
1058 }
1059 return (error);
1060 }
1061
1062 static moduledata_t linux_elf_mod = {
1063 "linuxelf",
1064 linux_elf_modevent,
1065 0
1066 };
1067
1068 DECLARE_MODULE_TIED(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
1069 MODULE_DEPEND(linuxelf, linux_common, 1, 1, 1);
1070 FEATURE(linux, "Linux 32bit support");
1071