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/linux/linux_emul_md.h>
65 #include <amd64/linux32/linux.h>
66 #include <amd64/linux32/linux32_proto.h>
67 #include <compat/linux/linux_elf.h>
68 #include <compat/linux/linux_emul.h>
69 #include <compat/linux/linux_fork.h>
70 #include <compat/linux/linux_ioctl.h>
71 #include <compat/linux/linux_mib.h>
72 #include <compat/linux/linux_misc.h>
73 #include <compat/linux/linux_signal.h>
74 #include <compat/linux/linux_util.h>
75 #include <compat/linux/linux_vdso.h>
76
77 #include <x86/linux/linux_x86_sigframe.h>
78
79 MODULE_VERSION(linux, 1);
80
81 #define LINUX32_MAXUSER ((1ul << 32) - PAGE_SIZE)
82 #define LINUX32_VDSOPAGE_SIZE PAGE_SIZE * 2
83 #define LINUX32_VDSOPAGE (LINUX32_MAXUSER - LINUX32_VDSOPAGE_SIZE)
84 #define LINUX32_SHAREDPAGE (LINUX32_VDSOPAGE - PAGE_SIZE)
85 /*
86 * PAGE_SIZE - the size
87 * of the native SHAREDPAGE
88 */
89 #define LINUX32_USRSTACK LINUX32_SHAREDPAGE
90
91 static int linux_szsigcode;
92 static vm_object_t linux_vdso_obj;
93 static char *linux_vdso_mapping;
94 extern char _binary_linux32_vdso_so_o_start;
95 extern char _binary_linux32_vdso_so_o_end;
96 static vm_offset_t linux_vdso_base;
97
98 extern struct sysent linux32_sysent[LINUX32_SYS_MAXSYSCALL];
99 extern const char *linux32_syscallnames[];
100
101 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);
102
103 static int linux_copyout_strings(struct image_params *imgp,
104 uintptr_t *stack_base);
105 static void linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask);
106 static void linux_exec_setregs(struct thread *td,
107 struct image_params *imgp, uintptr_t stack);
108 static void linux_exec_sysvec_init(void *param);
109 static int linux_on_exec_vmspace(struct proc *p,
110 struct image_params *imgp);
111 static void linux32_fixlimit(struct rlimit *rl, int which);
112 static void linux_vdso_install(const void *param);
113 static void linux_vdso_deinstall(const void *param);
114 static void linux_vdso_reloc(char *mapping, Elf_Addr offset);
115 static void linux32_set_fork_retval(struct thread *td);
116 static void linux32_set_syscall_retval(struct thread *td, int error);
117
118 struct linux32_ps_strings {
119 u_int32_t ps_argvstr; /* first of 0 or more argument strings */
120 u_int ps_nargvstr; /* the number of argument strings */
121 u_int32_t ps_envstr; /* first of 0 or more environment strings */
122 u_int ps_nenvstr; /* the number of environment strings */
123 };
124 #define LINUX32_PS_STRINGS (LINUX32_USRSTACK - \
125 sizeof(struct linux32_ps_strings))
126
127 LINUX_VDSO_SYM_INTPTR(__kernel_vsyscall);
128 LINUX_VDSO_SYM_INTPTR(linux32_vdso_sigcode);
129 LINUX_VDSO_SYM_INTPTR(linux32_vdso_rt_sigcode);
130 LINUX_VDSO_SYM_INTPTR(kern_timekeep_base);
131 LINUX_VDSO_SYM_INTPTR(kern_tsc_selector);
132 LINUX_VDSO_SYM_INTPTR(kern_cpu_selector);
133 LINUX_VDSO_SYM_CHAR(linux_platform);
134
135 void
linux32_arch_copyout_auxargs(struct image_params * imgp,Elf_Auxinfo ** pos)136 linux32_arch_copyout_auxargs(struct image_params *imgp, Elf_Auxinfo **pos)
137 {
138
139 AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO, __kernel_vsyscall);
140 AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO_EHDR, linux_vdso_base);
141 AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP, cpu_feature);
142 AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP2, linux_x86_elf_hwcap2());
143 AUXARGS_ENTRY((*pos), LINUX_AT_PLATFORM, PTROUT(linux_platform));
144 }
145
146 static void
linux_rt_sendsig(sig_t catcher,ksiginfo_t * ksi,sigset_t * mask)147 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
148 {
149 struct thread *td = curthread;
150 struct proc *p = td->td_proc;
151 struct sigacts *psp;
152 struct trapframe *regs;
153 struct l_rt_sigframe *fp, frame;
154 int oonstack;
155 int sig;
156 int code;
157
158 sig = linux_translate_traps(ksi->ksi_signo, ksi->ksi_trapno);
159 code = ksi->ksi_code;
160 PROC_LOCK_ASSERT(p, MA_OWNED);
161 psp = p->p_sigacts;
162 mtx_assert(&psp->ps_mtx, MA_OWNED);
163 regs = td->td_frame;
164 oonstack = sigonstack(regs->tf_rsp);
165
166 /* Allocate space for the signal handler context. */
167 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack &&
168 SIGISMEMBER(psp->ps_sigonstack, sig)) {
169 fp = (struct l_rt_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
170 td->td_sigstk.ss_size - sizeof(struct l_rt_sigframe));
171 } else
172 fp = (struct l_rt_sigframe *)regs->tf_rsp - 1;
173 mtx_unlock(&psp->ps_mtx);
174
175 /* Build the argument list for the signal handler. */
176 sig = bsd_to_linux_signal(sig);
177
178 bzero(&frame, sizeof(frame));
179
180 frame.sf_sig = sig;
181 frame.sf_siginfo = PTROUT(&fp->sf_si);
182 frame.sf_ucontext = PTROUT(&fp->sf_uc);
183
184 /* Fill in POSIX parts. */
185 siginfo_to_lsiginfo(&ksi->ksi_info, &frame.sf_si, sig);
186
187 /*
188 * Build the signal context to be used by sigreturn and libgcc unwind.
189 */
190 frame.sf_uc.uc_stack.ss_sp = PTROUT(td->td_sigstk.ss_sp);
191 frame.sf_uc.uc_stack.ss_size = td->td_sigstk.ss_size;
192 frame.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
193 ? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE;
194 PROC_UNLOCK(p);
195
196 bsd_to_linux_sigset(mask, &frame.sf_uc.uc_sigmask);
197
198 frame.sf_uc.uc_mcontext.sc_mask = frame.sf_uc.uc_sigmask.__mask;
199 frame.sf_uc.uc_mcontext.sc_edi = regs->tf_rdi;
200 frame.sf_uc.uc_mcontext.sc_esi = regs->tf_rsi;
201 frame.sf_uc.uc_mcontext.sc_ebp = regs->tf_rbp;
202 frame.sf_uc.uc_mcontext.sc_ebx = regs->tf_rbx;
203 frame.sf_uc.uc_mcontext.sc_esp = regs->tf_rsp;
204 frame.sf_uc.uc_mcontext.sc_edx = regs->tf_rdx;
205 frame.sf_uc.uc_mcontext.sc_ecx = regs->tf_rcx;
206 frame.sf_uc.uc_mcontext.sc_eax = regs->tf_rax;
207 frame.sf_uc.uc_mcontext.sc_eip = regs->tf_rip;
208 frame.sf_uc.uc_mcontext.sc_cs = regs->tf_cs;
209 frame.sf_uc.uc_mcontext.sc_gs = regs->tf_gs;
210 frame.sf_uc.uc_mcontext.sc_fs = regs->tf_fs;
211 frame.sf_uc.uc_mcontext.sc_es = regs->tf_es;
212 frame.sf_uc.uc_mcontext.sc_ds = regs->tf_ds;
213 frame.sf_uc.uc_mcontext.sc_eflags = regs->tf_rflags;
214 frame.sf_uc.uc_mcontext.sc_esp_at_signal = regs->tf_rsp;
215 frame.sf_uc.uc_mcontext.sc_ss = regs->tf_ss;
216 frame.sf_uc.uc_mcontext.sc_err = regs->tf_err;
217 frame.sf_uc.uc_mcontext.sc_cr2 = (u_int32_t)(uintptr_t)ksi->ksi_addr;
218 frame.sf_uc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code);
219
220 if (copyout(&frame, fp, sizeof(frame)) != 0) {
221 /*
222 * Process has trashed its stack; give it an illegal
223 * instruction to halt it in its tracks.
224 */
225 PROC_LOCK(p);
226 sigexit(td, SIGILL);
227 }
228
229 /* Build context to run handler in. */
230 regs->tf_rsp = PTROUT(fp);
231 regs->tf_rip = linux32_vdso_rt_sigcode;
232 regs->tf_rdi = PTROUT(catcher);
233 regs->tf_rflags &= ~(PSL_T | PSL_D);
234 regs->tf_cs = _ucode32sel;
235 regs->tf_ss = _udatasel;
236 regs->tf_ds = _udatasel;
237 regs->tf_es = _udatasel;
238 regs->tf_fs = _ufssel;
239 regs->tf_gs = _ugssel;
240 regs->tf_flags = TF_HASSEGS;
241 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
242 PROC_LOCK(p);
243 mtx_lock(&psp->ps_mtx);
244 }
245
246 /*
247 * Send an interrupt to process.
248 *
249 * Stack is set up to allow sigcode stored
250 * in u. to call routine, followed by kcall
251 * to sigreturn routine below. After sigreturn
252 * resets the signal mask, the stack, and the
253 * frame pointer, it returns to the user
254 * specified pc, psl.
255 */
256 static void
linux_sendsig(sig_t catcher,ksiginfo_t * ksi,sigset_t * mask)257 linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
258 {
259 struct thread *td = curthread;
260 struct proc *p = td->td_proc;
261 struct sigacts *psp;
262 struct trapframe *regs;
263 struct l_sigframe *fp, frame;
264 l_sigset_t lmask;
265 int oonstack;
266 int sig, code;
267
268 sig = linux_translate_traps(ksi->ksi_signo, ksi->ksi_trapno);
269 code = ksi->ksi_code;
270 PROC_LOCK_ASSERT(p, MA_OWNED);
271 psp = p->p_sigacts;
272 mtx_assert(&psp->ps_mtx, MA_OWNED);
273 if (SIGISMEMBER(psp->ps_siginfo, sig)) {
274 /* Signal handler installed with SA_SIGINFO. */
275 linux_rt_sendsig(catcher, ksi, mask);
276 return;
277 }
278
279 regs = td->td_frame;
280 oonstack = sigonstack(regs->tf_rsp);
281
282 /* Allocate space for the signal handler context. */
283 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack &&
284 SIGISMEMBER(psp->ps_sigonstack, sig)) {
285 fp = (struct l_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
286 td->td_sigstk.ss_size - sizeof(struct l_sigframe));
287 } else
288 fp = (struct l_sigframe *)regs->tf_rsp - 1;
289 mtx_unlock(&psp->ps_mtx);
290 PROC_UNLOCK(p);
291
292 /* Build the argument list for the signal handler. */
293 sig = bsd_to_linux_signal(sig);
294
295 bzero(&frame, sizeof(frame));
296
297 frame.sf_sig = sig;
298 frame.sf_sigmask = *mask;
299 bsd_to_linux_sigset(mask, &lmask);
300
301 /* Build the signal context to be used by sigreturn. */
302 frame.sf_sc.sc_mask = lmask.__mask;
303 frame.sf_sc.sc_gs = regs->tf_gs;
304 frame.sf_sc.sc_fs = regs->tf_fs;
305 frame.sf_sc.sc_es = regs->tf_es;
306 frame.sf_sc.sc_ds = regs->tf_ds;
307 frame.sf_sc.sc_edi = regs->tf_rdi;
308 frame.sf_sc.sc_esi = regs->tf_rsi;
309 frame.sf_sc.sc_ebp = regs->tf_rbp;
310 frame.sf_sc.sc_ebx = regs->tf_rbx;
311 frame.sf_sc.sc_esp = regs->tf_rsp;
312 frame.sf_sc.sc_edx = regs->tf_rdx;
313 frame.sf_sc.sc_ecx = regs->tf_rcx;
314 frame.sf_sc.sc_eax = regs->tf_rax;
315 frame.sf_sc.sc_eip = regs->tf_rip;
316 frame.sf_sc.sc_cs = regs->tf_cs;
317 frame.sf_sc.sc_eflags = regs->tf_rflags;
318 frame.sf_sc.sc_esp_at_signal = regs->tf_rsp;
319 frame.sf_sc.sc_ss = regs->tf_ss;
320 frame.sf_sc.sc_err = regs->tf_err;
321 frame.sf_sc.sc_cr2 = (u_int32_t)(uintptr_t)ksi->ksi_addr;
322 frame.sf_sc.sc_trapno = bsd_to_linux_trapcode(code);
323
324 if (copyout(&frame, fp, sizeof(frame)) != 0) {
325 /*
326 * Process has trashed its stack; give it an illegal
327 * instruction to halt it in its tracks.
328 */
329 PROC_LOCK(p);
330 sigexit(td, SIGILL);
331 }
332
333 /* Build context to run handler in. */
334 regs->tf_rsp = PTROUT(fp);
335 regs->tf_rip = linux32_vdso_sigcode;
336 regs->tf_rdi = PTROUT(catcher);
337 regs->tf_rflags &= ~(PSL_T | PSL_D);
338 regs->tf_cs = _ucode32sel;
339 regs->tf_ss = _udatasel;
340 regs->tf_ds = _udatasel;
341 regs->tf_es = _udatasel;
342 regs->tf_fs = _ufssel;
343 regs->tf_gs = _ugssel;
344 regs->tf_flags = TF_HASSEGS;
345 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
346 PROC_LOCK(p);
347 mtx_lock(&psp->ps_mtx);
348 }
349
350 /*
351 * System call to cleanup state after a signal
352 * has been taken. Reset signal mask and
353 * stack state from context left by sendsig (above).
354 * Return to previous pc and psl as specified by
355 * context left by sendsig. Check carefully to
356 * make sure that the user has not modified the
357 * psl to gain improper privileges or to cause
358 * a machine fault.
359 */
360 int
linux_sigreturn(struct thread * td,struct linux_sigreturn_args * args)361 linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
362 {
363 struct l_sigframe frame;
364 struct trapframe *regs;
365 int eflags;
366 ksiginfo_t ksi;
367
368 regs = td->td_frame;
369
370 /*
371 * The trampoline code hands us the sigframe.
372 * It is unsafe to keep track of it ourselves, in the event that a
373 * program jumps out of a signal handler.
374 */
375 if (copyin(args->sfp, &frame, sizeof(frame)) != 0)
376 return (EFAULT);
377
378 /* Check for security violations. */
379 eflags = frame.sf_sc.sc_eflags;
380 if (!EFL_SECURE(eflags, regs->tf_rflags))
381 return(EINVAL);
382
383 /*
384 * Don't allow users to load a valid privileged %cs. Let the
385 * hardware check for invalid selectors, excess privilege in
386 * other selectors, invalid %eip's and invalid %esp's.
387 */
388 if (!CS_SECURE(frame.sf_sc.sc_cs)) {
389 ksiginfo_init_trap(&ksi);
390 ksi.ksi_signo = SIGBUS;
391 ksi.ksi_code = BUS_OBJERR;
392 ksi.ksi_trapno = T_PROTFLT;
393 ksi.ksi_addr = (void *)regs->tf_rip;
394 trapsignal(td, &ksi);
395 return(EINVAL);
396 }
397
398 kern_sigprocmask(td, SIG_SETMASK, &frame.sf_sigmask, NULL, 0);
399
400 /* Restore signal context. */
401 regs->tf_rdi = frame.sf_sc.sc_edi;
402 regs->tf_rsi = frame.sf_sc.sc_esi;
403 regs->tf_rbp = frame.sf_sc.sc_ebp;
404 regs->tf_rbx = frame.sf_sc.sc_ebx;
405 regs->tf_rdx = frame.sf_sc.sc_edx;
406 regs->tf_rcx = frame.sf_sc.sc_ecx;
407 regs->tf_rax = frame.sf_sc.sc_eax;
408 regs->tf_rip = frame.sf_sc.sc_eip;
409 regs->tf_cs = frame.sf_sc.sc_cs;
410 regs->tf_ds = frame.sf_sc.sc_ds;
411 regs->tf_es = frame.sf_sc.sc_es;
412 regs->tf_fs = frame.sf_sc.sc_fs;
413 regs->tf_gs = frame.sf_sc.sc_gs;
414 regs->tf_rflags = eflags;
415 regs->tf_rsp = frame.sf_sc.sc_esp_at_signal;
416 regs->tf_ss = frame.sf_sc.sc_ss;
417 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
418
419 return (EJUSTRETURN);
420 }
421
422 /*
423 * System call to cleanup state after a signal
424 * has been taken. Reset signal mask and
425 * stack state from context left by rt_sendsig (above).
426 * Return to previous pc and psl as specified by
427 * context left by sendsig. Check carefully to
428 * make sure that the user has not modified the
429 * psl to gain improper privileges or to cause
430 * a machine fault.
431 */
432 int
linux_rt_sigreturn(struct thread * td,struct linux_rt_sigreturn_args * args)433 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
434 {
435 struct l_ucontext uc;
436 struct l_sigcontext *context;
437 sigset_t bmask;
438 l_stack_t *lss;
439 stack_t ss;
440 struct trapframe *regs;
441 int eflags;
442 ksiginfo_t ksi;
443
444 regs = td->td_frame;
445
446 /*
447 * The trampoline code hands us the ucontext.
448 * It is unsafe to keep track of it ourselves, in the event that a
449 * program jumps out of a signal handler.
450 */
451 if (copyin(args->ucp, &uc, sizeof(uc)) != 0)
452 return (EFAULT);
453
454 context = &uc.uc_mcontext;
455
456 /* Check for security violations. */
457 eflags = context->sc_eflags;
458 if (!EFL_SECURE(eflags, regs->tf_rflags))
459 return(EINVAL);
460
461 /*
462 * Don't allow users to load a valid privileged %cs. Let the
463 * hardware check for invalid selectors, excess privilege in
464 * other selectors, invalid %eip's and invalid %esp's.
465 */
466 if (!CS_SECURE(context->sc_cs)) {
467 ksiginfo_init_trap(&ksi);
468 ksi.ksi_signo = SIGBUS;
469 ksi.ksi_code = BUS_OBJERR;
470 ksi.ksi_trapno = T_PROTFLT;
471 ksi.ksi_addr = (void *)regs->tf_rip;
472 trapsignal(td, &ksi);
473 return(EINVAL);
474 }
475
476 linux_to_bsd_sigset(&uc.uc_sigmask, &bmask);
477 kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
478
479 /*
480 * Restore signal context
481 */
482 regs->tf_gs = context->sc_gs;
483 regs->tf_fs = context->sc_fs;
484 regs->tf_es = context->sc_es;
485 regs->tf_ds = context->sc_ds;
486 regs->tf_rdi = context->sc_edi;
487 regs->tf_rsi = context->sc_esi;
488 regs->tf_rbp = context->sc_ebp;
489 regs->tf_rbx = context->sc_ebx;
490 regs->tf_rdx = context->sc_edx;
491 regs->tf_rcx = context->sc_ecx;
492 regs->tf_rax = context->sc_eax;
493 regs->tf_rip = context->sc_eip;
494 regs->tf_cs = context->sc_cs;
495 regs->tf_rflags = eflags;
496 regs->tf_rsp = context->sc_esp_at_signal;
497 regs->tf_ss = context->sc_ss;
498 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
499
500 /*
501 * call sigaltstack & ignore results..
502 */
503 lss = &uc.uc_stack;
504 ss.ss_sp = PTRIN(lss->ss_sp);
505 ss.ss_size = lss->ss_size;
506 ss.ss_flags = linux_to_bsd_sigaltstack(lss->ss_flags);
507
508 (void)kern_sigaltstack(td, &ss, NULL);
509
510 return (EJUSTRETURN);
511 }
512
513 static int
linux32_fetch_syscall_args(struct thread * td)514 linux32_fetch_syscall_args(struct thread *td)
515 {
516 struct proc *p;
517 struct trapframe *frame;
518 struct syscall_args *sa;
519
520 p = td->td_proc;
521 frame = td->td_frame;
522 sa = &td->td_sa;
523
524 sa->args[0] = frame->tf_rbx;
525 sa->args[1] = frame->tf_rcx;
526 sa->args[2] = frame->tf_rdx;
527 sa->args[3] = frame->tf_rsi;
528 sa->args[4] = frame->tf_rdi;
529 sa->args[5] = frame->tf_rbp;
530 sa->code = frame->tf_rax;
531 sa->original_code = sa->code;
532
533 if (sa->code >= p->p_sysent->sv_size)
534 /* nosys */
535 sa->callp = &nosys_sysent;
536 else
537 sa->callp = &p->p_sysent->sv_table[sa->code];
538
539 td->td_retval[0] = 0;
540 td->td_retval[1] = frame->tf_rdx;
541
542 return (0);
543 }
544
545 static void
linux32_set_syscall_retval(struct thread * td,int error)546 linux32_set_syscall_retval(struct thread *td, int error)
547 {
548 struct trapframe *frame = td->td_frame;
549
550 cpu_set_syscall_retval(td, error);
551
552 if (__predict_false(error != 0)) {
553 if (error != ERESTART && error != EJUSTRETURN)
554 frame->tf_rax = bsd_to_linux_errno(error);
555 }
556 }
557
558 static void
linux32_set_fork_retval(struct thread * td)559 linux32_set_fork_retval(struct thread *td)
560 {
561 struct trapframe *frame = td->td_frame;
562
563 frame->tf_rax = 0;
564 }
565
566 /*
567 * Clear registers on exec
568 * XXX copied from ia32_signal.c.
569 */
570 static void
linux_exec_setregs(struct thread * td,struct image_params * imgp,uintptr_t stack)571 linux_exec_setregs(struct thread *td, struct image_params *imgp,
572 uintptr_t stack)
573 {
574 struct trapframe *regs = td->td_frame;
575 struct pcb *pcb = td->td_pcb;
576 register_t saved_rflags;
577
578 regs = td->td_frame;
579 pcb = td->td_pcb;
580
581 if (td->td_proc->p_md.md_ldt != NULL)
582 user_ldt_free(td);
583
584 /* Do full restore on return so that we can change to a different %cs */
585 set_pcb_flags(pcb, PCB_32BIT | PCB_FULL_IRET);
586 clear_pcb_flags(pcb, PCB_TLSBASE);
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 /* Linux processes start with PKRU denying unallocated keys. */
615 linux_pkru_exec_init(td);
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_minsigstksz = LINUX_MINSIGSTKSZ,
795 .sv_minuser = VM_MIN_ADDRESS,
796 .sv_maxuser = LINUX32_MAXUSER,
797 .sv_usrstack = LINUX32_USRSTACK,
798 .sv_psstrings = LINUX32_PS_STRINGS,
799 .sv_psstringssz = sizeof(struct linux32_ps_strings),
800 .sv_stackprot = VM_PROT_ALL,
801 .sv_copyout_auxargs = __linuxN(copyout_auxargs),
802 .sv_copyout_strings = linux_copyout_strings,
803 .sv_setregs = linux_exec_setregs,
804 .sv_fixlimit = linux32_fixlimit,
805 .sv_maxssiz = &linux32_maxssiz,
806 .sv_flags = SV_ABI_LINUX | SV_ILP32 | SV_SHP |
807 SV_SIG_DISCIGN | SV_SIG_WAITNDQ | SV_TIMEKEEP,
808 .sv_set_syscall_retval = linux32_set_syscall_retval,
809 .sv_fetch_syscall_args = linux32_fetch_syscall_args,
810 .sv_syscallnames = linux32_syscallnames,
811 .sv_shared_page_base = LINUX32_SHAREDPAGE,
812 .sv_shared_page_len = PAGE_SIZE,
813 .sv_schedtail = linux_schedtail,
814 .sv_thread_detach = linux_thread_detach,
815 .sv_trap = NULL,
816 .sv_hwcap = NULL,
817 .sv_hwcap2 = NULL,
818 .sv_hwcap3 = NULL,
819 .sv_hwcap4 = NULL,
820 .sv_onexec = linux_on_exec_vmspace,
821 .sv_onexit = linux_on_exit,
822 .sv_ontdexit = linux_thread_dtor,
823 .sv_setid_allowed = &linux_setid_allowed_query,
824 .sv_set_fork_retval = linux32_set_fork_retval,
825 };
826
827 static int
linux_on_exec_vmspace(struct proc * p,struct image_params * imgp)828 linux_on_exec_vmspace(struct proc *p, struct image_params *imgp)
829 {
830 int error;
831
832 error = linux_map_vdso(p, linux_vdso_obj, linux_vdso_base,
833 LINUX32_VDSOPAGE_SIZE, imgp);
834 if (error == 0)
835 error = linux_on_exec(p, imgp);
836 return (error);
837 }
838
839 /*
840 * linux_vdso_install() and linux_exec_sysvec_init() must be called
841 * after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY).
842 */
843 static void
linux_exec_sysvec_init(void * param)844 linux_exec_sysvec_init(void *param)
845 {
846 l_uintptr_t *ktimekeep_base, *ktsc_selector;
847 struct sysentvec *sv;
848 ptrdiff_t tkoff;
849
850 sv = param;
851 /* Fill timekeep_base */
852 exec_sysvec_init(sv);
853
854 tkoff = kern_timekeep_base - linux_vdso_base;
855 ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
856 *ktimekeep_base = sv->sv_shared_page_base + sv->sv_timekeep_offset;
857
858 tkoff = kern_tsc_selector - linux_vdso_base;
859 ktsc_selector = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
860 *ktsc_selector = linux_vdso_tsc_selector_idx();
861 if (bootverbose)
862 printf("Linux i386 vDSO tsc_selector: %u\n", *ktsc_selector);
863
864 tkoff = kern_cpu_selector - linux_vdso_base;
865 ktsc_selector = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
866 *ktsc_selector = linux_vdso_cpu_selector_idx();
867 if (bootverbose)
868 printf("Linux i386 vDSO cpu_selector: %u\n", *ktsc_selector);
869 }
870 SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY,
871 linux_exec_sysvec_init, &elf_linux_sysvec);
872
873 static void
linux_vdso_install(const void * param)874 linux_vdso_install(const void *param)
875 {
876 char *vdso_start = &_binary_linux32_vdso_so_o_start;
877 char *vdso_end = &_binary_linux32_vdso_so_o_end;
878
879 linux_szsigcode = vdso_end - vdso_start;
880 MPASS(linux_szsigcode <= LINUX32_VDSOPAGE_SIZE);
881
882 linux_vdso_base = LINUX32_VDSOPAGE;
883
884 __elfN(linux_vdso_fixup)(vdso_start, linux_vdso_base);
885
886 linux_vdso_obj = __elfN(linux_shared_page_init)
887 (&linux_vdso_mapping, LINUX32_VDSOPAGE_SIZE);
888 bcopy(vdso_start, linux_vdso_mapping, linux_szsigcode);
889
890 linux_vdso_reloc(linux_vdso_mapping, linux_vdso_base);
891 }
892 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC + 1, SI_ORDER_FIRST,
893 linux_vdso_install, NULL);
894
895 static void
linux_vdso_deinstall(const void * param)896 linux_vdso_deinstall(const void *param)
897 {
898
899 __elfN(linux_shared_page_fini)(linux_vdso_obj,
900 linux_vdso_mapping, LINUX32_VDSOPAGE_SIZE);
901 }
902 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST,
903 linux_vdso_deinstall, NULL);
904
905 static void
linux_vdso_reloc(char * mapping,Elf_Addr offset)906 linux_vdso_reloc(char *mapping, Elf_Addr offset)
907 {
908 const Elf_Shdr *shdr;
909 const Elf_Rel *rel;
910 const Elf_Ehdr *ehdr;
911 Elf32_Addr *where;
912 Elf_Size rtype, symidx;
913 Elf32_Addr addr, addend;
914 int i, relcnt;
915
916 MPASS(offset != 0);
917
918 relcnt = 0;
919 ehdr = (const Elf_Ehdr *)mapping;
920 shdr = (const Elf_Shdr *)(mapping + ehdr->e_shoff);
921 for (i = 0; i < ehdr->e_shnum; i++)
922 {
923 switch (shdr[i].sh_type) {
924 case SHT_REL:
925 rel = (const Elf_Rel *)(mapping + shdr[i].sh_offset);
926 relcnt = shdr[i].sh_size / sizeof(*rel);
927 break;
928 case SHT_RELA:
929 printf("Linux i386 vDSO: unexpected Rela section\n");
930 break;
931 }
932 }
933
934 for (i = 0; i < relcnt; i++, rel++) {
935 where = (Elf32_Addr *)(mapping + rel->r_offset);
936 addend = *where;
937 rtype = ELF_R_TYPE(rel->r_info);
938 symidx = ELF_R_SYM(rel->r_info);
939
940 switch (rtype) {
941 case R_386_NONE: /* none */
942 break;
943
944 case R_386_RELATIVE: /* B + A */
945 addr = (Elf32_Addr)PTROUT(offset + addend);
946 if (*where != addr)
947 *where = addr;
948 break;
949
950 case R_386_IRELATIVE:
951 printf("Linux i386 vDSO: unexpected ifunc relocation, "
952 "symbol index %ld\n", (intmax_t)symidx);
953 break;
954 default:
955 printf("Linux i386 vDSO: unexpected relocation type %ld, "
956 "symbol index %ld\n", (intmax_t)rtype, (intmax_t)symidx);
957 }
958 }
959 }
960
961 static const Elf_Brandnote linux32_brandnote = {
962 .hdr.n_namesz = sizeof(GNU_ABI_VENDOR),
963 .hdr.n_descsz = 16, /* XXX at least 16 */
964 .hdr.n_type = 1,
965 .vendor = GNU_ABI_VENDOR,
966 .flags = BN_TRANSLATE_OSREL,
967 .trans_osrel = linux_trans_osrel
968 };
969
970 static const Elf32_Brandinfo linux_brand = {
971 .brand = ELFOSABI_LINUX,
972 .machine = EM_386,
973 .compat_3_brand = "Linux",
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 const Elf32_Brandinfo linux_glibc2brand = {
982 .brand = ELFOSABI_LINUX,
983 .machine = EM_386,
984 .compat_3_brand = "Linux",
985 .interp_path = "/lib/ld-linux.so.2",
986 .sysvec = &elf_linux_sysvec,
987 .interp_newpath = NULL,
988 .brand_note = &linux32_brandnote,
989 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
990 };
991
992 static const Elf32_Brandinfo linux_muslbrand = {
993 .brand = ELFOSABI_LINUX,
994 .machine = EM_386,
995 .compat_3_brand = "Linux",
996 .interp_path = "/lib/ld-musl-i386.so.1",
997 .sysvec = &elf_linux_sysvec,
998 .interp_newpath = NULL,
999 .brand_note = &linux32_brandnote,
1000 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE |
1001 LINUX_BI_FUTEX_REQUEUE
1002 };
1003
1004 static const Elf32_Brandinfo *linux_brandlist[] = {
1005 &linux_brand,
1006 &linux_glibc2brand,
1007 &linux_muslbrand,
1008 NULL
1009 };
1010
1011 static int
linux_elf_modevent(module_t mod,int type,void * data)1012 linux_elf_modevent(module_t mod, int type, void *data)
1013 {
1014 const Elf32_Brandinfo **brandinfo;
1015 int error;
1016 struct linux_ioctl_handler **lihp;
1017
1018 error = 0;
1019
1020 switch(type) {
1021 case MOD_LOAD:
1022 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
1023 ++brandinfo)
1024 if (elf32_insert_brand_entry(*brandinfo) < 0)
1025 error = EINVAL;
1026 if (error == 0) {
1027 SET_FOREACH(lihp, linux_ioctl_handler_set)
1028 linux32_ioctl_register_handler(*lihp);
1029 stclohz = (stathz ? stathz : hz);
1030 if (bootverbose)
1031 printf("Linux i386 ELF exec handler installed\n");
1032 } else
1033 printf("cannot insert Linux i386 ELF brand handler\n");
1034 break;
1035 case MOD_UNLOAD:
1036 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
1037 ++brandinfo)
1038 if (elf32_brand_inuse(*brandinfo))
1039 error = EBUSY;
1040 if (error == 0) {
1041 for (brandinfo = &linux_brandlist[0];
1042 *brandinfo != NULL; ++brandinfo)
1043 if (elf32_remove_brand_entry(*brandinfo) < 0)
1044 error = EINVAL;
1045 }
1046 if (error == 0) {
1047 SET_FOREACH(lihp, linux_ioctl_handler_set)
1048 linux32_ioctl_unregister_handler(*lihp);
1049 if (bootverbose)
1050 printf("Linux i386 ELF exec handler removed\n");
1051 } else
1052 printf("Could not deinstall Linux i386 ELF interpreter entry\n");
1053 break;
1054 default:
1055 return (EOPNOTSUPP);
1056 }
1057 return (error);
1058 }
1059
1060 static moduledata_t linux_elf_mod = {
1061 "linuxelf",
1062 linux_elf_modevent,
1063 0
1064 };
1065
1066 DECLARE_MODULE_TIED(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
1067 MODULE_DEPEND(linuxelf, linux_common, 1, 1, 1);
1068 FEATURE(linux, "Linux 32bit support");
1069