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opnsense-src/sys/amd64/linux32/linux32_sysvec.c
Dmitry Chagin d5dc757e84 linux(4): Add compat.linux32.emulate_i386 knob. 
Historically 32-bit Linuxulator under amd64 emulated the real i386
behavior. Since 3d8dd983 the old i386 Linux world can't be used under
amd64 Linuxulator as it don't know anything about amd64 machine (which
is returned now by newuname() syscall). So, add a knob to allow to swith
the behavior and use i386 Linux binaries on amd64.
Set knob to the new behavior as I think this is common to the modern
Linux distros.

Reviewed by:		Pau Amma (doc), emaste
Differential revision:	https://reviews.freebsd.org/D34708
MFC after:		2 weeks
2022-03-31 21:01:09 +03:00

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2004 Tim J. Robbins
* Copyright (c) 2003 Peter Wemm
* Copyright (c) 2002 Doug Rabson
* Copyright (c) 1998-1999 Andrew Gallatin
* Copyright (c) 1994-1996 Søren Schmidt
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "opt_compat.h"
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#ifndef COMPAT_FREEBSD32
#error "Unable to compile Linux-emulator due to missing COMPAT_FREEBSD32 option!"
#endif
#define __ELF_WORD_SIZE 32
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/exec.h>
#include <sys/fcntl.h>
#include <sys/imgact.h>
#include <sys/imgact_elf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/stddef.h>
#include <sys/signalvar.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/vnode.h>
#include <sys/eventhandler.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_extern.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_param.h>
#include <machine/cpu.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/specialreg.h>
#include <machine/trap.h>
#include <x86/linux/linux_x86.h>
#include <amd64/linux32/linux.h>
#include <amd64/linux32/linux32_proto.h>
#include <compat/linux/linux_emul.h>
#include <compat/linux/linux_fork.h>
#include <compat/linux/linux_ioctl.h>
#include <compat/linux/linux_mib.h>
#include <compat/linux/linux_misc.h>
#include <compat/linux/linux_signal.h>
#include <compat/linux/linux_util.h>
#include <compat/linux/linux_vdso.h>
MODULE_VERSION(linux, 1);
#define LINUX32_MAXUSER ((1ul << 32) - PAGE_SIZE)
#define LINUX32_VDSOPAGE_SIZE PAGE_SIZE * 2
#define LINUX32_VDSOPAGE (LINUX32_MAXUSER - LINUX32_VDSOPAGE_SIZE)
#define LINUX32_SHAREDPAGE (LINUX32_VDSOPAGE - PAGE_SIZE)
/*
* PAGE_SIZE - the size
* of the native SHAREDPAGE
*/
#define LINUX32_USRSTACK LINUX32_SHAREDPAGE
static int linux_szsigcode;
static vm_object_t linux_vdso_obj;
static char *linux_vdso_mapping;
extern char _binary_linux32_vdso_so_o_start;
extern char _binary_linux32_vdso_so_o_end;
static vm_offset_t linux_vdso_base;
extern struct sysent linux32_sysent[LINUX32_SYS_MAXSYSCALL];
SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);
static int linux_fixup_elf(uintptr_t *stack_base,
struct image_params *iparams);
static int linux_copyout_strings(struct image_params *imgp,
uintptr_t *stack_base);
static void linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask);
static void linux_exec_setregs(struct thread *td,
struct image_params *imgp, uintptr_t stack);
static void linux_exec_sysvec_init(void *param);
static int linux_on_exec_vmspace(struct proc *p,
struct image_params *imgp);
static void linux32_fixlimit(struct rlimit *rl, int which);
static bool linux32_trans_osrel(const Elf_Note *note, int32_t *osrel);
static void linux_vdso_install(const void *param);
static void linux_vdso_deinstall(const void *param);
static void linux_vdso_reloc(char *mapping, Elf_Addr offset);
static void linux32_set_fork_retval(struct thread *td);
static void linux32_set_syscall_retval(struct thread *td, int error);
#define LINUX_T_UNKNOWN 255
static int _bsd_to_linux_trapcode[] = {
LINUX_T_UNKNOWN, /* 0 */
6, /* 1 T_PRIVINFLT */
LINUX_T_UNKNOWN, /* 2 */
3, /* 3 T_BPTFLT */
LINUX_T_UNKNOWN, /* 4 */
LINUX_T_UNKNOWN, /* 5 */
16, /* 6 T_ARITHTRAP */
254, /* 7 T_ASTFLT */
LINUX_T_UNKNOWN, /* 8 */
13, /* 9 T_PROTFLT */
1, /* 10 T_TRCTRAP */
LINUX_T_UNKNOWN, /* 11 */
14, /* 12 T_PAGEFLT */
LINUX_T_UNKNOWN, /* 13 */
17, /* 14 T_ALIGNFLT */
LINUX_T_UNKNOWN, /* 15 */
LINUX_T_UNKNOWN, /* 16 */
LINUX_T_UNKNOWN, /* 17 */
0, /* 18 T_DIVIDE */
2, /* 19 T_NMI */
4, /* 20 T_OFLOW */
5, /* 21 T_BOUND */
7, /* 22 T_DNA */
8, /* 23 T_DOUBLEFLT */
9, /* 24 T_FPOPFLT */
10, /* 25 T_TSSFLT */
11, /* 26 T_SEGNPFLT */
12, /* 27 T_STKFLT */
18, /* 28 T_MCHK */
19, /* 29 T_XMMFLT */
15 /* 30 T_RESERVED */
};
#define bsd_to_linux_trapcode(code) \
((code)<nitems(_bsd_to_linux_trapcode)? \
_bsd_to_linux_trapcode[(code)]: \
LINUX_T_UNKNOWN)
struct linux32_ps_strings {
u_int32_t ps_argvstr; /* first of 0 or more argument strings */
u_int ps_nargvstr; /* the number of argument strings */
u_int32_t ps_envstr; /* first of 0 or more environment strings */
u_int ps_nenvstr; /* the number of environment strings */
};
#define LINUX32_PS_STRINGS (LINUX32_USRSTACK - \
sizeof(struct linux32_ps_strings))
LINUX_VDSO_SYM_INTPTR(__kernel_vsyscall);
LINUX_VDSO_SYM_INTPTR(__kernel_sigreturn);
LINUX_VDSO_SYM_INTPTR(__kernel_rt_sigreturn);
LINUX_VDSO_SYM_INTPTR(kern_timekeep_base);
LINUX_VDSO_SYM_INTPTR(kern_tsc_selector);
LINUX_VDSO_SYM_CHAR(linux_platform);
/*
* If FreeBSD & Linux have a difference of opinion about what a trap
* means, deal with it here.
*
* MPSAFE
*/
static int
linux_translate_traps(int signal, int trap_code)
{
if (signal != SIGBUS)
return (signal);
switch (trap_code) {
case T_PROTFLT:
case T_TSSFLT:
case T_DOUBLEFLT:
case T_PAGEFLT:
return (SIGSEGV);
default:
return (signal);
}
}
static int
linux_copyout_auxargs(struct image_params *imgp, uintptr_t base)
{
Elf32_Auxargs *args;
Elf32_Auxinfo *argarray, *pos;
int error, issetugid;
args = (Elf32_Auxargs *)imgp->auxargs;
argarray = pos = malloc(LINUX_AT_COUNT * sizeof(*pos), M_TEMP,
M_WAITOK | M_ZERO);
issetugid = imgp->proc->p_flag & P_SUGID ? 1 : 0;
AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO, __kernel_vsyscall);
AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO_EHDR, linux_vdso_base);
AUXARGS_ENTRY(pos, LINUX_AT_HWCAP, cpu_feature);
AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
/*
* Do not export AT_CLKTCK when emulating Linux kernel prior to 2.4.0,
* as it has appeared in the 2.4.0-rc7 first time.
* Being exported, AT_CLKTCK is returned by sysconf(_SC_CLK_TCK),
* glibc falls back to the hard-coded CLK_TCK value when aux entry
* is not present.
* Also see linux_times() implementation.
*/
if (linux_kernver(curthread) >= LINUX_KERNVER_2004000)
AUXARGS_ENTRY(pos, LINUX_AT_CLKTCK, stclohz);
AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
AUXARGS_ENTRY(pos, AT_BASE, args->base);
AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid);
AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid);
AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid);
AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid);
AUXARGS_ENTRY(pos, LINUX_AT_SECURE, issetugid);
AUXARGS_ENTRY(pos, LINUX_AT_RANDOM, PTROUT(imgp->canary));
AUXARGS_ENTRY(pos, LINUX_AT_HWCAP2, 0);
if (imgp->execpathp != 0)
AUXARGS_ENTRY(pos, LINUX_AT_EXECFN, PTROUT(imgp->execpathp));
if (args->execfd != -1)
AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
AUXARGS_ENTRY(pos, LINUX_AT_PLATFORM, PTROUT(linux_platform));
AUXARGS_ENTRY(pos, AT_NULL, 0);
free(imgp->auxargs, M_TEMP);
imgp->auxargs = NULL;
KASSERT(pos - argarray <= LINUX_AT_COUNT, ("Too many auxargs"));
error = copyout(argarray, (void *)base,
sizeof(*argarray) * LINUX_AT_COUNT);
free(argarray, M_TEMP);
return (error);
}
static int
linux_fixup_elf(uintptr_t *stack_base, struct image_params *imgp)
{
Elf32_Addr *base;
base = (Elf32_Addr *)*stack_base;
base--;
if (suword32(base, (uint32_t)imgp->args->argc) == -1)
return (EFAULT);
*stack_base = (uintptr_t)base;
return (0);
}
static void
linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
{
struct thread *td = curthread;
struct proc *p = td->td_proc;
struct sigacts *psp;
struct trapframe *regs;
struct l_rt_sigframe *fp, frame;
int oonstack;
int sig;
int code;
sig = ksi->ksi_signo;
code = ksi->ksi_code;
PROC_LOCK_ASSERT(p, MA_OWNED);
psp = p->p_sigacts;
mtx_assert(&psp->ps_mtx, MA_OWNED);
regs = td->td_frame;
oonstack = sigonstack(regs->tf_rsp);
/* Allocate space for the signal handler context. */
if ((td->td_pflags & TDP_ALTSTACK) && !oonstack &&
SIGISMEMBER(psp->ps_sigonstack, sig)) {
fp = (struct l_rt_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
td->td_sigstk.ss_size - sizeof(struct l_rt_sigframe));
} else
fp = (struct l_rt_sigframe *)regs->tf_rsp - 1;
mtx_unlock(&psp->ps_mtx);
/* Build the argument list for the signal handler. */
sig = bsd_to_linux_signal(sig);
bzero(&frame, sizeof(frame));
frame.sf_handler = PTROUT(catcher);
frame.sf_sig = sig;
frame.sf_siginfo = PTROUT(&fp->sf_si);
frame.sf_ucontext = PTROUT(&fp->sf_sc);
/* Fill in POSIX parts. */
siginfo_to_lsiginfo(&ksi->ksi_info, &frame.sf_si, sig);
/*
* Build the signal context to be used by sigreturn and libgcc unwind.
*/
frame.sf_sc.uc_flags = 0; /* XXX ??? */
frame.sf_sc.uc_link = 0; /* XXX ??? */
frame.sf_sc.uc_stack.ss_sp = PTROUT(td->td_sigstk.ss_sp);
frame.sf_sc.uc_stack.ss_size = td->td_sigstk.ss_size;
frame.sf_sc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE;
PROC_UNLOCK(p);
bsd_to_linux_sigset(mask, &frame.sf_sc.uc_sigmask);
frame.sf_sc.uc_mcontext.sc_mask = frame.sf_sc.uc_sigmask.__mask;
frame.sf_sc.uc_mcontext.sc_edi = regs->tf_rdi;
frame.sf_sc.uc_mcontext.sc_esi = regs->tf_rsi;
frame.sf_sc.uc_mcontext.sc_ebp = regs->tf_rbp;
frame.sf_sc.uc_mcontext.sc_ebx = regs->tf_rbx;
frame.sf_sc.uc_mcontext.sc_esp = regs->tf_rsp;
frame.sf_sc.uc_mcontext.sc_edx = regs->tf_rdx;
frame.sf_sc.uc_mcontext.sc_ecx = regs->tf_rcx;
frame.sf_sc.uc_mcontext.sc_eax = regs->tf_rax;
frame.sf_sc.uc_mcontext.sc_eip = regs->tf_rip;
frame.sf_sc.uc_mcontext.sc_cs = regs->tf_cs;
frame.sf_sc.uc_mcontext.sc_gs = regs->tf_gs;
frame.sf_sc.uc_mcontext.sc_fs = regs->tf_fs;
frame.sf_sc.uc_mcontext.sc_es = regs->tf_es;
frame.sf_sc.uc_mcontext.sc_ds = regs->tf_ds;
frame.sf_sc.uc_mcontext.sc_eflags = regs->tf_rflags;
frame.sf_sc.uc_mcontext.sc_esp_at_signal = regs->tf_rsp;
frame.sf_sc.uc_mcontext.sc_ss = regs->tf_ss;
frame.sf_sc.uc_mcontext.sc_err = regs->tf_err;
frame.sf_sc.uc_mcontext.sc_cr2 = (u_int32_t)(uintptr_t)ksi->ksi_addr;
frame.sf_sc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code);
if (copyout(&frame, fp, sizeof(frame)) != 0) {
/*
* Process has trashed its stack; give it an illegal
* instruction to halt it in its tracks.
*/
PROC_LOCK(p);
sigexit(td, SIGILL);
}
/* Build context to run handler in. */
regs->tf_rsp = PTROUT(fp);
regs->tf_rip = __kernel_rt_sigreturn;
regs->tf_rflags &= ~(PSL_T | PSL_D);
regs->tf_cs = _ucode32sel;
regs->tf_ss = _udatasel;
regs->tf_ds = _udatasel;
regs->tf_es = _udatasel;
regs->tf_fs = _ufssel;
regs->tf_gs = _ugssel;
regs->tf_flags = TF_HASSEGS;
set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
PROC_LOCK(p);
mtx_lock(&psp->ps_mtx);
}
/*
* Send an interrupt to process.
*
* Stack is set up to allow sigcode stored
* in u. to call routine, followed by kcall
* to sigreturn routine below. After sigreturn
* resets the signal mask, the stack, and the
* frame pointer, it returns to the user
* specified pc, psl.
*/
static void
linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
{
struct thread *td = curthread;
struct proc *p = td->td_proc;
struct sigacts *psp;
struct trapframe *regs;
struct l_sigframe *fp, frame;
l_sigset_t lmask;
int oonstack;
int sig, code;
sig = ksi->ksi_signo;
code = ksi->ksi_code;
PROC_LOCK_ASSERT(p, MA_OWNED);
psp = p->p_sigacts;
mtx_assert(&psp->ps_mtx, MA_OWNED);
if (SIGISMEMBER(psp->ps_siginfo, sig)) {
/* Signal handler installed with SA_SIGINFO. */
linux_rt_sendsig(catcher, ksi, mask);
return;
}
regs = td->td_frame;
oonstack = sigonstack(regs->tf_rsp);
/* Allocate space for the signal handler context. */
if ((td->td_pflags & TDP_ALTSTACK) && !oonstack &&
SIGISMEMBER(psp->ps_sigonstack, sig)) {
fp = (struct l_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
td->td_sigstk.ss_size - sizeof(struct l_sigframe));
} else
fp = (struct l_sigframe *)regs->tf_rsp - 1;
mtx_unlock(&psp->ps_mtx);
PROC_UNLOCK(p);
/* Build the argument list for the signal handler. */
sig = bsd_to_linux_signal(sig);
bzero(&frame, sizeof(frame));
frame.sf_handler = PTROUT(catcher);
frame.sf_sig = sig;
bsd_to_linux_sigset(mask, &lmask);
/* Build the signal context to be used by sigreturn. */
frame.sf_sc.sc_mask = lmask.__mask;
frame.sf_sc.sc_gs = regs->tf_gs;
frame.sf_sc.sc_fs = regs->tf_fs;
frame.sf_sc.sc_es = regs->tf_es;
frame.sf_sc.sc_ds = regs->tf_ds;
frame.sf_sc.sc_edi = regs->tf_rdi;
frame.sf_sc.sc_esi = regs->tf_rsi;
frame.sf_sc.sc_ebp = regs->tf_rbp;
frame.sf_sc.sc_ebx = regs->tf_rbx;
frame.sf_sc.sc_esp = regs->tf_rsp;
frame.sf_sc.sc_edx = regs->tf_rdx;
frame.sf_sc.sc_ecx = regs->tf_rcx;
frame.sf_sc.sc_eax = regs->tf_rax;
frame.sf_sc.sc_eip = regs->tf_rip;
frame.sf_sc.sc_cs = regs->tf_cs;
frame.sf_sc.sc_eflags = regs->tf_rflags;
frame.sf_sc.sc_esp_at_signal = regs->tf_rsp;
frame.sf_sc.sc_ss = regs->tf_ss;
frame.sf_sc.sc_err = regs->tf_err;
frame.sf_sc.sc_cr2 = (u_int32_t)(uintptr_t)ksi->ksi_addr;
frame.sf_sc.sc_trapno = bsd_to_linux_trapcode(code);
frame.sf_extramask[0] = lmask.__mask;
if (copyout(&frame, fp, sizeof(frame)) != 0) {
/*
* Process has trashed its stack; give it an illegal
* instruction to halt it in its tracks.
*/
PROC_LOCK(p);
sigexit(td, SIGILL);
}
/* Build context to run handler in. */
regs->tf_rsp = PTROUT(fp);
regs->tf_rip = __kernel_sigreturn;
regs->tf_rflags &= ~(PSL_T | PSL_D);
regs->tf_cs = _ucode32sel;
regs->tf_ss = _udatasel;
regs->tf_ds = _udatasel;
regs->tf_es = _udatasel;
regs->tf_fs = _ufssel;
regs->tf_gs = _ugssel;
regs->tf_flags = TF_HASSEGS;
set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
PROC_LOCK(p);
mtx_lock(&psp->ps_mtx);
}
/*
* System call to cleanup state after a signal
* has been taken. Reset signal mask and
* stack state from context left by sendsig (above).
* Return to previous pc and psl as specified by
* context left by sendsig. Check carefully to
* make sure that the user has not modified the
* psl to gain improper privileges or to cause
* a machine fault.
*/
int
linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
{
struct l_sigframe frame;
struct trapframe *regs;
sigset_t bmask;
l_sigset_t lmask;
int eflags;
ksiginfo_t ksi;
regs = td->td_frame;
/*
* The trampoline code hands us the sigframe.
* It is unsafe to keep track of it ourselves, in the event that a
* program jumps out of a signal handler.
*/
if (copyin(args->sfp, &frame, sizeof(frame)) != 0)
return (EFAULT);
/* Check for security violations. */
eflags = frame.sf_sc.sc_eflags;
if (!EFL_SECURE(eflags, regs->tf_rflags))
return(EINVAL);
/*
* Don't allow users to load a valid privileged %cs. Let the
* hardware check for invalid selectors, excess privilege in
* other selectors, invalid %eip's and invalid %esp's.
*/
if (!CS_SECURE(frame.sf_sc.sc_cs)) {
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGBUS;
ksi.ksi_code = BUS_OBJERR;
ksi.ksi_trapno = T_PROTFLT;
ksi.ksi_addr = (void *)regs->tf_rip;
trapsignal(td, &ksi);
return(EINVAL);
}
lmask.__mask = frame.sf_sc.sc_mask;
lmask.__mask = frame.sf_extramask[0];
linux_to_bsd_sigset(&lmask, &bmask);
kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
/* Restore signal context. */
regs->tf_rdi = frame.sf_sc.sc_edi;
regs->tf_rsi = frame.sf_sc.sc_esi;
regs->tf_rbp = frame.sf_sc.sc_ebp;
regs->tf_rbx = frame.sf_sc.sc_ebx;
regs->tf_rdx = frame.sf_sc.sc_edx;
regs->tf_rcx = frame.sf_sc.sc_ecx;
regs->tf_rax = frame.sf_sc.sc_eax;
regs->tf_rip = frame.sf_sc.sc_eip;
regs->tf_cs = frame.sf_sc.sc_cs;
regs->tf_ds = frame.sf_sc.sc_ds;
regs->tf_es = frame.sf_sc.sc_es;
regs->tf_fs = frame.sf_sc.sc_fs;
regs->tf_gs = frame.sf_sc.sc_gs;
regs->tf_rflags = eflags;
regs->tf_rsp = frame.sf_sc.sc_esp_at_signal;
regs->tf_ss = frame.sf_sc.sc_ss;
set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
return (EJUSTRETURN);
}
/*
* System call to cleanup state after a signal
* has been taken. Reset signal mask and
* stack state from context left by rt_sendsig (above).
* Return to previous pc and psl as specified by
* context left by sendsig. Check carefully to
* make sure that the user has not modified the
* psl to gain improper privileges or to cause
* a machine fault.
*/
int
linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
{
struct l_ucontext uc;
struct l_sigcontext *context;
sigset_t bmask;
l_stack_t *lss;
stack_t ss;
struct trapframe *regs;
int eflags;
ksiginfo_t ksi;
regs = td->td_frame;
/*
* The trampoline code hands us the ucontext.
* It is unsafe to keep track of it ourselves, in the event that a
* program jumps out of a signal handler.
*/
if (copyin(args->ucp, &uc, sizeof(uc)) != 0)
return (EFAULT);
context = &uc.uc_mcontext;
/* Check for security violations. */
eflags = context->sc_eflags;
if (!EFL_SECURE(eflags, regs->tf_rflags))
return(EINVAL);
/*
* Don't allow users to load a valid privileged %cs. Let the
* hardware check for invalid selectors, excess privilege in
* other selectors, invalid %eip's and invalid %esp's.
*/
if (!CS_SECURE(context->sc_cs)) {
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGBUS;
ksi.ksi_code = BUS_OBJERR;
ksi.ksi_trapno = T_PROTFLT;
ksi.ksi_addr = (void *)regs->tf_rip;
trapsignal(td, &ksi);
return(EINVAL);
}
linux_to_bsd_sigset(&uc.uc_sigmask, &bmask);
kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
/*
* Restore signal context
*/
regs->tf_gs = context->sc_gs;
regs->tf_fs = context->sc_fs;
regs->tf_es = context->sc_es;
regs->tf_ds = context->sc_ds;
regs->tf_rdi = context->sc_edi;
regs->tf_rsi = context->sc_esi;
regs->tf_rbp = context->sc_ebp;
regs->tf_rbx = context->sc_ebx;
regs->tf_rdx = context->sc_edx;
regs->tf_rcx = context->sc_ecx;
regs->tf_rax = context->sc_eax;
regs->tf_rip = context->sc_eip;
regs->tf_cs = context->sc_cs;
regs->tf_rflags = eflags;
regs->tf_rsp = context->sc_esp_at_signal;
regs->tf_ss = context->sc_ss;
set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
/*
* call sigaltstack & ignore results..
*/
lss = &uc.uc_stack;
ss.ss_sp = PTRIN(lss->ss_sp);
ss.ss_size = lss->ss_size;
ss.ss_flags = linux_to_bsd_sigaltstack(lss->ss_flags);
(void)kern_sigaltstack(td, &ss, NULL);
return (EJUSTRETURN);
}
static int
linux32_fetch_syscall_args(struct thread *td)
{
struct proc *p;
struct trapframe *frame;
struct syscall_args *sa;
p = td->td_proc;
frame = td->td_frame;
sa = &td->td_sa;
sa->args[0] = frame->tf_rbx;
sa->args[1] = frame->tf_rcx;
sa->args[2] = frame->tf_rdx;
sa->args[3] = frame->tf_rsi;
sa->args[4] = frame->tf_rdi;
sa->args[5] = frame->tf_rbp; /* Unconfirmed */
sa->code = frame->tf_rax;
sa->original_code = sa->code;
if (sa->code >= p->p_sysent->sv_size)
/* nosys */
sa->callp = &p->p_sysent->sv_table[p->p_sysent->sv_size - 1];
else
sa->callp = &p->p_sysent->sv_table[sa->code];
td->td_retval[0] = 0;
td->td_retval[1] = frame->tf_rdx;
return (0);
}
static void
linux32_set_syscall_retval(struct thread *td, int error)
{
struct trapframe *frame = td->td_frame;
cpu_set_syscall_retval(td, error);
if (__predict_false(error != 0)) {
if (error != ERESTART && error != EJUSTRETURN)
frame->tf_rax = bsd_to_linux_errno(error);
}
}
static void
linux32_set_fork_retval(struct thread *td)
{
struct trapframe *frame = td->td_frame;
frame->tf_rax = 0;
}
/*
* Clear registers on exec
* XXX copied from ia32_signal.c.
*/
static void
linux_exec_setregs(struct thread *td, struct image_params *imgp,
uintptr_t stack)
{
struct trapframe *regs = td->td_frame;
struct pcb *pcb = td->td_pcb;
register_t saved_rflags;
regs = td->td_frame;
pcb = td->td_pcb;
if (td->td_proc->p_md.md_ldt != NULL)
user_ldt_free(td);
critical_enter();
wrmsr(MSR_FSBASE, 0);
wrmsr(MSR_KGSBASE, 0); /* User value while we're in the kernel */
pcb->pcb_fsbase = 0;
pcb->pcb_gsbase = 0;
critical_exit();
pcb->pcb_initial_fpucw = __LINUX_NPXCW__;
saved_rflags = regs->tf_rflags & PSL_T;
bzero((char *)regs, sizeof(struct trapframe));
regs->tf_rip = imgp->entry_addr;
regs->tf_rsp = stack;
regs->tf_rflags = PSL_USER | saved_rflags;
regs->tf_gs = _ugssel;
regs->tf_fs = _ufssel;
regs->tf_es = _udatasel;
regs->tf_ds = _udatasel;
regs->tf_ss = _udatasel;
regs->tf_flags = TF_HASSEGS;
regs->tf_cs = _ucode32sel;
regs->tf_rbx = (register_t)imgp->ps_strings;
x86_clear_dbregs(pcb);
fpstate_drop(td);
/* Do full restore on return so that we can change to a different %cs */
set_pcb_flags(pcb, PCB_32BIT | PCB_FULL_IRET);
}
/*
* XXX copied from ia32_sysvec.c.
*/
static int
linux_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
{
int argc, envc, error;
u_int32_t *vectp;
char *stringp;
uintptr_t destp, ustringp;
struct linux32_ps_strings *arginfo;
char canary[LINUX_AT_RANDOM_LEN];
size_t execpath_len;
arginfo = (struct linux32_ps_strings *)PROC_PS_STRINGS(imgp->proc);
destp = (uintptr_t)arginfo;
if (imgp->execpath != NULL && imgp->auxargs != NULL) {
execpath_len = strlen(imgp->execpath) + 1;
destp -= execpath_len;
destp = rounddown2(destp, sizeof(uint32_t));
imgp->execpathp = (void *)destp;
error = copyout(imgp->execpath, imgp->execpathp, execpath_len);
if (error != 0)
return (error);
}
/* Prepare the canary for SSP. */
arc4rand(canary, sizeof(canary), 0);
destp -= roundup(sizeof(canary), sizeof(uint32_t));
imgp->canary = (void *)destp;
error = copyout(canary, imgp->canary, sizeof(canary));
if (error != 0)
return (error);
/* Allocate room for the argument and environment strings. */
destp -= ARG_MAX - imgp->args->stringspace;
destp = rounddown2(destp, sizeof(uint32_t));
ustringp = destp;
if (imgp->auxargs) {
/*
* Allocate room on the stack for the ELF auxargs
* array. It has LINUX_AT_COUNT entries.
*/
destp -= LINUX_AT_COUNT * sizeof(Elf32_Auxinfo);
destp = rounddown2(destp, sizeof(uint32_t));
}
vectp = (uint32_t *)destp;
/*
* Allocate room for the argv[] and env vectors including the
* terminating NULL pointers.
*/
vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
/* vectp also becomes our initial stack base. */
*stack_base = (uintptr_t)vectp;
stringp = imgp->args->begin_argv;
argc = imgp->args->argc;
envc = imgp->args->envc;
/* Copy out strings - arguments and environment. */
error = copyout(stringp, (void *)ustringp,
ARG_MAX - imgp->args->stringspace);
if (error != 0)
return (error);
/* Fill in "ps_strings" struct for ps, w, etc. */
if (suword32(&arginfo->ps_argvstr, (uint32_t)(intptr_t)vectp) != 0 ||
suword32(&arginfo->ps_nargvstr, argc) != 0)
return (EFAULT);
/* Fill in argument portion of vector table. */
for (; argc > 0; --argc) {
if (suword32(vectp++, ustringp) != 0)
return (EFAULT);
while (*stringp++ != 0)
ustringp++;
ustringp++;
}
/* A null vector table pointer separates the argp's from the envp's. */
if (suword32(vectp++, 0) != 0)
return (EFAULT);
if (suword32(&arginfo->ps_envstr, (uint32_t)(intptr_t)vectp) != 0 ||
suword32(&arginfo->ps_nenvstr, envc) != 0)
return (EFAULT);
/* Fill in environment portion of vector table. */
for (; envc > 0; --envc) {
if (suword32(vectp++, ustringp) != 0)
return (EFAULT);
while (*stringp++ != 0)
ustringp++;
ustringp++;
}
/* The end of the vector table is a null pointer. */
if (suword32(vectp, 0) != 0)
return (EFAULT);
if (imgp->auxargs) {
vectp++;
error = imgp->sysent->sv_copyout_auxargs(imgp,
(uintptr_t)vectp);
if (error != 0)
return (error);
}
return (0);
}
static SYSCTL_NODE(_compat, OID_AUTO, linux32, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"32-bit Linux emulation");
static u_long linux32_maxdsiz = LINUX32_MAXDSIZ;
SYSCTL_ULONG(_compat_linux32, OID_AUTO, maxdsiz, CTLFLAG_RW,
&linux32_maxdsiz, 0, "");
static u_long linux32_maxssiz = LINUX32_MAXSSIZ;
SYSCTL_ULONG(_compat_linux32, OID_AUTO, maxssiz, CTLFLAG_RW,
&linux32_maxssiz, 0, "");
static u_long linux32_maxvmem = LINUX32_MAXVMEM;
SYSCTL_ULONG(_compat_linux32, OID_AUTO, maxvmem, CTLFLAG_RW,
&linux32_maxvmem, 0, "");
bool linux32_emulate_i386 = false;
SYSCTL_BOOL(_compat_linux32, OID_AUTO, emulate_i386, CTLFLAG_RWTUN,
&linux32_emulate_i386, 0, "Emulate the real i386");
static void
linux32_fixlimit(struct rlimit *rl, int which)
{
switch (which) {
case RLIMIT_DATA:
if (linux32_maxdsiz != 0) {
if (rl->rlim_cur > linux32_maxdsiz)
rl->rlim_cur = linux32_maxdsiz;
if (rl->rlim_max > linux32_maxdsiz)
rl->rlim_max = linux32_maxdsiz;
}
break;
case RLIMIT_STACK:
if (linux32_maxssiz != 0) {
if (rl->rlim_cur > linux32_maxssiz)
rl->rlim_cur = linux32_maxssiz;
if (rl->rlim_max > linux32_maxssiz)
rl->rlim_max = linux32_maxssiz;
}
break;
case RLIMIT_VMEM:
if (linux32_maxvmem != 0) {
if (rl->rlim_cur > linux32_maxvmem)
rl->rlim_cur = linux32_maxvmem;
if (rl->rlim_max > linux32_maxvmem)
rl->rlim_max = linux32_maxvmem;
}
break;
}
}
struct sysentvec elf_linux_sysvec = {
.sv_size = LINUX32_SYS_MAXSYSCALL,
.sv_table = linux32_sysent,
.sv_transtrap = linux_translate_traps,
.sv_fixup = linux_fixup_elf,
.sv_sendsig = linux_sendsig,
.sv_sigcode = &_binary_linux32_vdso_so_o_start,
.sv_szsigcode = &linux_szsigcode,
.sv_name = "Linux ELF32",
.sv_coredump = elf32_coredump,
.sv_elf_core_osabi = ELFOSABI_NONE,
.sv_elf_core_abi_vendor = LINUX_ABI_VENDOR,
.sv_elf_core_prepare_notes = linux32_prepare_notes,
.sv_imgact_try = linux_exec_imgact_try,
.sv_minsigstksz = LINUX_MINSIGSTKSZ,
.sv_minuser = VM_MIN_ADDRESS,
.sv_maxuser = LINUX32_MAXUSER,
.sv_usrstack = LINUX32_USRSTACK,
.sv_psstrings = LINUX32_PS_STRINGS,
.sv_psstringssz = sizeof(struct linux32_ps_strings),
.sv_stackprot = VM_PROT_ALL,
.sv_copyout_auxargs = linux_copyout_auxargs,
.sv_copyout_strings = linux_copyout_strings,
.sv_setregs = linux_exec_setregs,
.sv_fixlimit = linux32_fixlimit,
.sv_maxssiz = &linux32_maxssiz,
.sv_flags = SV_ABI_LINUX | SV_ILP32 | SV_IA32 | SV_SHP |
SV_SIG_DISCIGN | SV_SIG_WAITNDQ | SV_TIMEKEEP,
.sv_set_syscall_retval = linux32_set_syscall_retval,
.sv_fetch_syscall_args = linux32_fetch_syscall_args,
.sv_syscallnames = NULL,
.sv_shared_page_base = LINUX32_SHAREDPAGE,
.sv_shared_page_len = PAGE_SIZE,
.sv_schedtail = linux_schedtail,
.sv_thread_detach = linux_thread_detach,
.sv_trap = NULL,
.sv_onexec = linux_on_exec_vmspace,
.sv_onexit = linux_on_exit,
.sv_ontdexit = linux_thread_dtor,
.sv_setid_allowed = &linux_setid_allowed_query,
.sv_set_fork_retval = linux32_set_fork_retval,
};
static int
linux_on_exec_vmspace(struct proc *p, struct image_params *imgp)
{
int error;
error = linux_map_vdso(p, linux_vdso_obj, linux_vdso_base,
LINUX32_VDSOPAGE_SIZE, imgp);
if (error == 0)
linux_on_exec(p, imgp);
return (error);
}
/*
* linux_vdso_install() and linux_exec_sysvec_init() must be called
* after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY).
*/
static void
linux_exec_sysvec_init(void *param)
{
l_uintptr_t *ktimekeep_base, *ktsc_selector;
struct sysentvec *sv;
ptrdiff_t tkoff;
sv = param;
/* Fill timekeep_base */
exec_sysvec_init(sv);
tkoff = kern_timekeep_base - linux_vdso_base;
ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
*ktimekeep_base = sv->sv_timekeep_base;
tkoff = kern_tsc_selector - linux_vdso_base;
ktsc_selector = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
*ktsc_selector = linux_vdso_tsc_selector_idx();
if (bootverbose)
printf("Linux i386 vDSO tsc_selector: %u\n", *ktsc_selector);
}
SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY,
linux_exec_sysvec_init, &elf_linux_sysvec);
static void
linux_vdso_install(const void *param)
{
char *vdso_start = &_binary_linux32_vdso_so_o_start;
char *vdso_end = &_binary_linux32_vdso_so_o_end;
linux_szsigcode = vdso_end - vdso_start;
MPASS(linux_szsigcode <= LINUX32_VDSOPAGE_SIZE);
linux_vdso_base = LINUX32_VDSOPAGE;
__elfN(linux_vdso_fixup)(vdso_start, linux_vdso_base);
linux_vdso_obj = __elfN(linux_shared_page_init)
(&linux_vdso_mapping, LINUX32_VDSOPAGE_SIZE);
bcopy(vdso_start, linux_vdso_mapping, linux_szsigcode);
linux_vdso_reloc(linux_vdso_mapping, linux_vdso_base);
}
SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC + 1, SI_ORDER_FIRST,
linux_vdso_install, NULL);
static void
linux_vdso_deinstall(const void *param)
{
__elfN(linux_shared_page_fini)(linux_vdso_obj,
linux_vdso_mapping, LINUX32_VDSOPAGE_SIZE);
}
SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST,
linux_vdso_deinstall, NULL);
static void
linux_vdso_reloc(char *mapping, Elf_Addr offset)
{
const Elf_Shdr *shdr;
const Elf_Rel *rel;
const Elf_Ehdr *ehdr;
Elf32_Addr *where;
Elf_Size rtype, symidx;
Elf32_Addr addr, addend;
int i, relcnt;
MPASS(offset != 0);
relcnt = 0;
ehdr = (const Elf_Ehdr *)mapping;
shdr = (const Elf_Shdr *)(mapping + ehdr->e_shoff);
for (i = 0; i < ehdr->e_shnum; i++)
{
switch (shdr[i].sh_type) {
case SHT_REL:
rel = (const Elf_Rel *)(mapping + shdr[i].sh_offset);
relcnt = shdr[i].sh_size / sizeof(*rel);
break;
case SHT_RELA:
printf("Linux i386 vDSO: unexpected Rela section\n");
break;
}
}
for (i = 0; i < relcnt; i++, rel++) {
where = (Elf32_Addr *)(mapping + rel->r_offset);
addend = *where;
rtype = ELF_R_TYPE(rel->r_info);
symidx = ELF_R_SYM(rel->r_info);
switch (rtype) {
case R_386_NONE: /* none */
break;
case R_386_RELATIVE: /* B + A */
addr = (Elf32_Addr)PTROUT(offset + addend);
if (*where != addr)
*where = addr;
break;
case R_386_IRELATIVE:
printf("Linux i386 vDSO: unexpected ifunc relocation, "
"symbol index %ld\n", (intmax_t)symidx);
break;
default:
printf("Linux i386 vDSO: unexpected relocation type %ld, "
"symbol index %ld\n", (intmax_t)rtype, (intmax_t)symidx);
}
}
}
static char GNU_ABI_VENDOR[] = "GNU";
static int GNULINUX_ABI_DESC = 0;
static bool
linux32_trans_osrel(const Elf_Note *note, int32_t *osrel)
{
const Elf32_Word *desc;
uintptr_t p;
p = (uintptr_t)(note + 1);
p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
desc = (const Elf32_Word *)p;
if (desc[0] != GNULINUX_ABI_DESC)
return (false);
/*
* For Linux we encode osrel using the Linux convention of
* (version << 16) | (major << 8) | (minor)
* See macro in linux_mib.h
*/
*osrel = LINUX_KERNVER(desc[1], desc[2], desc[3]);
return (true);
}
static Elf_Brandnote linux32_brandnote = {
.hdr.n_namesz = sizeof(GNU_ABI_VENDOR),
.hdr.n_descsz = 16, /* XXX at least 16 */
.hdr.n_type = 1,
.vendor = GNU_ABI_VENDOR,
.flags = BN_TRANSLATE_OSREL,
.trans_osrel = linux32_trans_osrel
};
static Elf32_Brandinfo linux_brand = {
.brand = ELFOSABI_LINUX,
.machine = EM_386,
.compat_3_brand = "Linux",
.emul_path = linux_emul_path,
.interp_path = "/lib/ld-linux.so.1",
.sysvec = &elf_linux_sysvec,
.interp_newpath = NULL,
.brand_note = &linux32_brandnote,
.flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
};
static Elf32_Brandinfo linux_glibc2brand = {
.brand = ELFOSABI_LINUX,
.machine = EM_386,
.compat_3_brand = "Linux",
.emul_path = linux_emul_path,
.interp_path = "/lib/ld-linux.so.2",
.sysvec = &elf_linux_sysvec,
.interp_newpath = NULL,
.brand_note = &linux32_brandnote,
.flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
};
static Elf32_Brandinfo linux_muslbrand = {
.brand = ELFOSABI_LINUX,
.machine = EM_386,
.compat_3_brand = "Linux",
.emul_path = linux_emul_path,
.interp_path = "/lib/ld-musl-i386.so.1",
.sysvec = &elf_linux_sysvec,
.interp_newpath = NULL,
.brand_note = &linux32_brandnote,
.flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE |
LINUX_BI_FUTEX_REQUEUE
};
Elf32_Brandinfo *linux_brandlist[] = {
&linux_brand,
&linux_glibc2brand,
&linux_muslbrand,
NULL
};
static int
linux_elf_modevent(module_t mod, int type, void *data)
{
Elf32_Brandinfo **brandinfo;
int error;
struct linux_ioctl_handler **lihp;
error = 0;
switch(type) {
case MOD_LOAD:
for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
++brandinfo)
if (elf32_insert_brand_entry(*brandinfo) < 0)
error = EINVAL;
if (error == 0) {
SET_FOREACH(lihp, linux_ioctl_handler_set)
linux32_ioctl_register_handler(*lihp);
stclohz = (stathz ? stathz : hz);
if (bootverbose)
printf("Linux i386 ELF exec handler installed\n");
} else
printf("cannot insert Linux i386 ELF brand handler\n");
break;
case MOD_UNLOAD:
for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
++brandinfo)
if (elf32_brand_inuse(*brandinfo))
error = EBUSY;
if (error == 0) {
for (brandinfo = &linux_brandlist[0];
*brandinfo != NULL; ++brandinfo)
if (elf32_remove_brand_entry(*brandinfo) < 0)
error = EINVAL;
}
if (error == 0) {
SET_FOREACH(lihp, linux_ioctl_handler_set)
linux32_ioctl_unregister_handler(*lihp);
if (bootverbose)
printf("Linux i386 ELF exec handler removed\n");
} else
printf("Could not deinstall Linux i386 ELF interpreter entry\n");
break;
default:
return (EOPNOTSUPP);
}
return (error);
}
static moduledata_t linux_elf_mod = {
"linuxelf",
linux_elf_modevent,
0
};
DECLARE_MODULE_TIED(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
MODULE_DEPEND(linuxelf, linux_common, 1, 1, 1);
FEATURE(linux, "Linux 32bit support");
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