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