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freebsd-nq/sys/i386/linux/linux_sysvec.c
Marcel Moolenaar d034d459da Don't use p->p_sigstk.ss_flags to keep state of whether the 
process is on the alternate stack or not. For compatibility
with sigstack(2) state is being updated if such is needed.

We now determine whether the process is on the alternate
stack by looking at its stack pointer. This allows a process
to siglongjmp from a signal handler on the alternate stack
to the place of the sigsetjmp on the normal stack. When
maintaining state, this would have invalidated the state
information and causing a subsequent signal to be delivered
on the normal stack instead of the alternate stack.

PR: 22286
2000-11-30 05:23:49 +00:00

832 lines
24 KiB
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/*-
* 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 withough 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.
*
* $FreeBSD$
*/
/* XXX we use functions that might not exist. */
#include "opt_compat.h"
#ifndef COMPAT_43
#error "Unable to compile Linux-emulator due to missing COMPAT_43 option!"
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/sysproto.h>
#include <sys/sysent.h>
#include <sys/imgact.h>
#include <sys/imgact_aout.h>
#include <sys/imgact_elf.h>
#include <sys/signalvar.h>
#include <sys/malloc.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_page.h>
#include <vm/vm_extern.h>
#include <sys/exec.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <machine/cpu.h>
#include <i386/linux/linux.h>
#include <i386/linux/linux_proto.h>
#include <compat/linux/linux_signal.h>
#include <compat/linux/linux_util.h>
MODULE_VERSION(linux, 1);
MALLOC_DEFINE(M_LINUX, "linux", "Linux mode structures");
#if BYTE_ORDER == LITTLE_ENDIAN
#define SHELLMAGIC 0x2123 /* #! */
#else
#define SHELLMAGIC 0x2321
#endif
extern char linux_sigcode[];
extern int linux_szsigcode;
extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL];
extern struct linker_set linux_ioctl_handler_set;
static int linux_fixup __P((register_t **stack_base,
struct image_params *iparams));
static int elf_linux_fixup __P((register_t **stack_base,
struct image_params *iparams));
static void linux_prepsyscall __P((struct trapframe *tf, int *args,
u_int *code, caddr_t *params));
static void linux_sendsig __P((sig_t catcher, int sig, sigset_t *mask,
u_long code));
/*
* Linux syscalls return negative errno's, we do positive and map them
*/
static int bsd_to_linux_errno[ELAST + 1] = {
-0, -1, -2, -3, -4, -5, -6, -7, -8, -9,
-10, -35, -12, -13, -14, -15, -16, -17, -18, -19,
-20, -21, -22, -23, -24, -25, -26, -27, -28, -29,
-30, -31, -32, -33, -34, -11,-115,-114, -88, -89,
-90, -91, -92, -93, -94, -95, -96, -97, -98, -99,
-100,-101,-102,-103,-104,-105,-106,-107,-108,-109,
-110,-111, -40, -36,-112,-113, -39, -11, -87,-122,
-116, -66, -6, -6, -6, -6, -6, -37, -38, -9,
-6, -6, -43, -42, -75, -6, -84
};
int bsd_to_linux_signal[LINUX_SIGTBLSZ] = {
LINUX_SIGHUP, LINUX_SIGINT, LINUX_SIGQUIT, LINUX_SIGILL,
LINUX_SIGTRAP, LINUX_SIGABRT, 0, LINUX_SIGFPE,
LINUX_SIGKILL, LINUX_SIGBUS, LINUX_SIGSEGV, 0,
LINUX_SIGPIPE, LINUX_SIGALRM, LINUX_SIGTERM, LINUX_SIGURG,
LINUX_SIGSTOP, LINUX_SIGTSTP, LINUX_SIGCONT, LINUX_SIGCHLD,
LINUX_SIGTTIN, LINUX_SIGTTOU, LINUX_SIGIO, LINUX_SIGXCPU,
LINUX_SIGXFSZ, LINUX_SIGVTALRM, LINUX_SIGPROF, LINUX_SIGWINCH,
0, LINUX_SIGUSR1, LINUX_SIGUSR2
};
int linux_to_bsd_signal[LINUX_SIGTBLSZ] = {
SIGHUP, SIGINT, SIGQUIT, SIGILL,
SIGTRAP, SIGABRT, SIGBUS, SIGFPE,
SIGKILL, SIGUSR1, SIGSEGV, SIGUSR2,
SIGPIPE, SIGALRM, SIGTERM, SIGBUS,
SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP,
SIGTTIN, SIGTTOU, SIGURG, SIGXCPU,
SIGXFSZ, SIGVTALRM, SIGPROF, SIGWINCH,
SIGIO, SIGURG, 0
};
/*
* If FreeBSD & Linux have a difference of opinion about what a trap
* means, deal with it here.
*/
static int
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_fixup(register_t **stack_base, struct image_params *imgp)
{
register_t *argv, *envp;
argv = *stack_base;
envp = *stack_base + (imgp->argc + 1);
(*stack_base)--;
**stack_base = (intptr_t)(void *)envp;
(*stack_base)--;
**stack_base = (intptr_t)(void *)argv;
(*stack_base)--;
**stack_base = imgp->argc;
return 0;
}
static int
elf_linux_fixup(register_t **stack_base, struct image_params *imgp)
{
Elf32_Auxargs *args = (Elf32_Auxargs *)imgp->auxargs;
register_t *pos;
pos = *stack_base + (imgp->argc + imgp->envc + 2);
if (args->trace) {
AUXARGS_ENTRY(pos, AT_DEBUG, 1);
}
if (args->execfd != -1) {
AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
}
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_PAGESZ, args->pagesz);
AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
AUXARGS_ENTRY(pos, AT_BASE, args->base);
AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_cred->p_ruid);
AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_cred->p_svuid);
AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_cred->p_rgid);
AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_cred->p_svgid);
AUXARGS_ENTRY(pos, AT_NULL, 0);
free(imgp->auxargs, M_TEMP);
imgp->auxargs = NULL;
(*stack_base)--;
**stack_base = (long)imgp->argc;
return 0;
}
extern int _ucodesel, _udatasel;
extern unsigned long _linux_sznonrtsigcode;
static void
linux_rt_sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
{
register struct proc *p = curproc;
register struct trapframe *regs;
struct linux_rt_sigframe *fp, frame;
int oonstack;
regs = p->p_md.md_regs;
oonstack = sigonstack(regs->tf_esp);
#ifdef DEBUG
printf("Linux-emul(%ld): linux_rt_sendsig(%p, %d, %p, %lu)\n",
(long)p->p_pid, catcher, sig, (void*)mask, code);
#endif
/*
* Allocate space for the signal handler context.
*/
if ((p->p_flag & P_ALTSTACK) && !oonstack &&
SIGISMEMBER(p->p_sigacts->ps_sigonstack, sig)) {
fp = (struct linux_rt_sigframe *)(p->p_sigstk.ss_sp +
p->p_sigstk.ss_size - sizeof(struct linux_rt_sigframe));
} else
fp = (struct linux_rt_sigframe *)regs->tf_esp - 1;
/*
* grow() will return FALSE if the fp will not fit inside the stack
* and the stack can not be grown. useracc will return FALSE
* if access is denied.
*/
if ((grow_stack (p, (int)fp) == FALSE) ||
!useracc((caddr_t)fp, sizeof (struct linux_rt_sigframe),
VM_PROT_WRITE)) {
/*
* Process has trashed its stack; give it an illegal
* instruction to halt it in its tracks.
*/
SIGACTION(p, SIGILL) = SIG_DFL;
SIGDELSET(p->p_sigignore, SIGILL);
SIGDELSET(p->p_sigcatch, SIGILL);
SIGDELSET(p->p_sigmask, SIGILL);
#ifdef DEBUG
printf("Linux-emul(%ld): linux_rt_sendsig -- bad stack %p, "
"oonstack=%x\n", (long)p->p_pid, fp, oonstack);
#endif
psignal(p, SIGILL);
return;
}
/*
* Build the argument list for the signal handler.
*/
if (p->p_sysent->sv_sigtbl)
if (sig <= p->p_sysent->sv_sigsize)
sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
frame.sf_handler = catcher;
frame.sf_sig = sig;
frame.sf_siginfo = &fp->sf_si;
frame.sf_ucontext = &fp->sf_sc;
/* Fill siginfo structure. */
frame.sf_si.lsi_signo = sig;
frame.sf_si.lsi_code = code;
frame.sf_si.lsi_addr = (void *)regs->tf_err;
/*
* Build the signal context to be used by sigreturn.
*/
frame.sf_sc.uc_flags = 0; /* XXX ??? */
frame.sf_sc.uc_link = NULL; /* XXX ??? */
frame.sf_sc.uc_stack.ss_sp = p->p_sigstk.ss_sp;
frame.sf_sc.uc_stack.ss_size = p->p_sigstk.ss_size;
frame.sf_sc.uc_stack.ss_flags = (p->p_flag & P_ALTSTACK)
? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE;
bsd_to_linux_sigset(mask, &frame.sf_sc.uc_sigmask);
frame.sf_sc.uc_mcontext.sc_mask = frame.sf_sc.uc_sigmask.__bits[0];
frame.sf_sc.uc_mcontext.sc_gs = rgs();
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_edi = regs->tf_edi;
frame.sf_sc.uc_mcontext.sc_esi = regs->tf_esi;
frame.sf_sc.uc_mcontext.sc_ebp = regs->tf_ebp;
frame.sf_sc.uc_mcontext.sc_ebx = regs->tf_ebx;
frame.sf_sc.uc_mcontext.sc_edx = regs->tf_edx;
frame.sf_sc.uc_mcontext.sc_ecx = regs->tf_ecx;
frame.sf_sc.uc_mcontext.sc_eax = regs->tf_eax;
frame.sf_sc.uc_mcontext.sc_eip = regs->tf_eip;
frame.sf_sc.uc_mcontext.sc_cs = regs->tf_cs;
frame.sf_sc.uc_mcontext.sc_eflags = regs->tf_eflags;
frame.sf_sc.uc_mcontext.sc_esp_at_signal = regs->tf_esp;
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_trapno = code; /* XXX ???? */
#ifdef DEBUG
printf("Linux-emul(%ld): rt_sendsig flags: 0x%x, sp: %p, ss: 0x%x, "
"mask: 0x%x\n", (long)p->p_pid, frame.sf_sc.uc_stack.ss_flags,
p->p_sigstk.ss_sp, p->p_sigstk.ss_size,
frame.sf_sc.uc_mcontext.sc_mask);
#endif
if (copyout(&frame, fp, sizeof(frame)) != 0) {
/*
* Process has trashed its stack; give it an illegal
* instruction to halt it in its tracks.
*/
sigexit(p, SIGILL);
/* NOTREACHED */
}
/*
* Build context to run handler in.
*/
regs->tf_esp = (int)fp;
regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode) +
_linux_sznonrtsigcode;
regs->tf_eflags &= ~PSL_VM;
regs->tf_cs = _ucodesel;
regs->tf_ds = _udatasel;
regs->tf_es = _udatasel;
regs->tf_fs = _udatasel;
load_gs(_udatasel);
regs->tf_ss = _udatasel;
}
/*
* 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, int sig, sigset_t *mask, u_long code)
{
register struct proc *p = curproc;
register struct trapframe *regs;
struct linux_sigframe *fp, frame;
linux_sigset_t lmask;
int oonstack, i;
if (SIGISMEMBER(p->p_sigacts->ps_siginfo, sig)) {
/* Signal handler installed with SA_SIGINFO. */
linux_rt_sendsig(catcher, sig, mask, code);
return;
}
regs = p->p_md.md_regs;
oonstack = sigonstack(regs->tf_esp);
#ifdef DEBUG
printf("Linux-emul(%ld): linux_sendsig(%p, %d, %p, %lu)\n",
(long)p->p_pid, catcher, sig, (void*)mask, code);
#endif
/*
* Allocate space for the signal handler context.
*/
if ((p->p_flag & P_ALTSTACK) && !oonstack &&
SIGISMEMBER(p->p_sigacts->ps_sigonstack, sig)) {
fp = (struct linux_sigframe *)(p->p_sigstk.ss_sp +
p->p_sigstk.ss_size - sizeof(struct linux_sigframe));
} else
fp = (struct linux_sigframe *)regs->tf_esp - 1;
/*
* grow() will return FALSE if the fp will not fit inside the stack
* and the stack can not be grown. useracc will return FALSE
* if access is denied.
*/
if ((grow_stack (p, (int)fp) == FALSE) ||
!useracc((caddr_t)fp, sizeof (struct linux_sigframe),
VM_PROT_WRITE)) {
/*
* Process has trashed its stack; give it an illegal
* instruction to halt it in its tracks.
*/
SIGACTION(p, SIGILL) = SIG_DFL;
SIGDELSET(p->p_sigignore, SIGILL);
SIGDELSET(p->p_sigcatch, SIGILL);
SIGDELSET(p->p_sigmask, SIGILL);
psignal(p, SIGILL);
return;
}
/*
* Build the argument list for the signal handler.
*/
if (p->p_sysent->sv_sigtbl)
if (sig <= p->p_sysent->sv_sigsize)
sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
frame.sf_handler = 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.__bits[0];
frame.sf_sc.sc_gs = rgs();
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_edi;
frame.sf_sc.sc_esi = regs->tf_esi;
frame.sf_sc.sc_ebp = regs->tf_ebp;
frame.sf_sc.sc_ebx = regs->tf_ebx;
frame.sf_sc.sc_edx = regs->tf_edx;
frame.sf_sc.sc_ecx = regs->tf_ecx;
frame.sf_sc.sc_eax = regs->tf_eax;
frame.sf_sc.sc_eip = regs->tf_eip;
frame.sf_sc.sc_cs = regs->tf_cs;
frame.sf_sc.sc_eflags = regs->tf_eflags;
frame.sf_sc.sc_esp_at_signal = regs->tf_esp;
frame.sf_sc.sc_ss = regs->tf_ss;
frame.sf_sc.sc_err = regs->tf_err;
frame.sf_sc.sc_trapno = code; /* XXX ???? */
bzero(&frame.sf_fpstate, sizeof(struct linux_fpstate));
for (i = 0; i < (LINUX_NSIG_WORDS-1); i++)
frame.sf_extramask[i] = lmask.__bits[i+1];
if (copyout(&frame, fp, sizeof(frame)) != 0) {
/*
* Process has trashed its stack; give it an illegal
* instruction to halt it in its tracks.
*/
sigexit(p, SIGILL);
/* NOTREACHED */
}
/*
* Build context to run handler in.
*/
regs->tf_esp = (int)fp;
regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode);
regs->tf_eflags &= ~PSL_VM;
regs->tf_cs = _ucodesel;
regs->tf_ds = _udatasel;
regs->tf_es = _udatasel;
regs->tf_fs = _udatasel;
load_gs(_udatasel);
regs->tf_ss = _udatasel;
}
/*
* 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(p, args)
struct proc *p;
struct linux_sigreturn_args *args;
{
struct linux_sigframe frame;
register struct trapframe *regs;
linux_sigset_t lmask;
int eflags, i;
regs = p->p_md.md_regs;
#ifdef DEBUG
printf("Linux-emul(%ld): linux_sigreturn(%p)\n",
(long)p->p_pid, (void *)args->sfp);
#endif
/*
* 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((caddr_t)args->sfp, &frame, sizeof(frame)) != 0)
return (EFAULT);
/*
* Check for security violations.
*/
#define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
eflags = frame.sf_sc.sc_eflags;
/*
* XXX do allow users to change the privileged flag PSL_RF. The
* cpu sets PSL_RF in tf_eflags for faults. Debuggers should
* sometimes set it there too. tf_eflags is kept in the signal
* context during signal handling and there is no other place
* to remember it, so the PSL_RF bit may be corrupted by the
* signal handler without us knowing. Corruption of the PSL_RF
* bit at worst causes one more or one less debugger trap, so
* allowing it is fairly harmless.
*/
if (!EFLAGS_SECURE(eflags & ~PSL_RF, regs->tf_eflags & ~PSL_RF)) {
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.
*/
#define CS_SECURE(cs) (ISPL(cs) == SEL_UPL)
if (!CS_SECURE(frame.sf_sc.sc_cs)) {
trapsignal(p, SIGBUS, T_PROTFLT);
return(EINVAL);
}
lmask.__bits[0] = frame.sf_sc.sc_mask;
for (i = 0; i < (LINUX_NSIG_WORDS-1); i++)
lmask.__bits[i+1] = frame.sf_extramask[i];
linux_to_bsd_sigset(&lmask, &p->p_sigmask);
SIG_CANTMASK(p->p_sigmask);
/*
* Restore signal context.
*/
/* %gs was restored by the trampoline. */
regs->tf_fs = frame.sf_sc.sc_fs;
regs->tf_es = frame.sf_sc.sc_es;
regs->tf_ds = frame.sf_sc.sc_ds;
regs->tf_edi = frame.sf_sc.sc_edi;
regs->tf_esi = frame.sf_sc.sc_esi;
regs->tf_ebp = frame.sf_sc.sc_ebp;
regs->tf_ebx = frame.sf_sc.sc_ebx;
regs->tf_edx = frame.sf_sc.sc_edx;
regs->tf_ecx = frame.sf_sc.sc_ecx;
regs->tf_eax = frame.sf_sc.sc_eax;
regs->tf_eip = frame.sf_sc.sc_eip;
regs->tf_cs = frame.sf_sc.sc_cs;
regs->tf_eflags = eflags;
regs->tf_esp = frame.sf_sc.sc_esp_at_signal;
regs->tf_ss = frame.sf_sc.sc_ss;
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(p, args)
struct proc *p;
struct linux_rt_sigreturn_args *args;
{
struct sigaltstack_args sasargs;
struct linux_ucontext uc;
struct linux_sigcontext *context;
linux_stack_t *lss;
stack_t *ss;
register struct trapframe *regs;
int eflags;
caddr_t sg = stackgap_init();
regs = p->p_md.md_regs;
#ifdef DEBUG
printf("Linux-emul(%ld): linux_rt_sigreturn(%p)\n",
(long)p->p_pid, (void *)args->ucp);
#endif
/*
* 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((caddr_t)args->ucp, &uc, sizeof(uc)) != 0)
return (EFAULT);
context = &uc.uc_mcontext;
/*
* Check for security violations.
*/
#define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
eflags = context->sc_eflags;
/*
* XXX do allow users to change the privileged flag PSL_RF. The
* cpu sets PSL_RF in tf_eflags for faults. Debuggers should
* sometimes set it there too. tf_eflags is kept in the signal
* context during signal handling and there is no other place
* to remember it, so the PSL_RF bit may be corrupted by the
* signal handler without us knowing. Corruption of the PSL_RF
* bit at worst causes one more or one less debugger trap, so
* allowing it is fairly harmless.
*/
if (!EFLAGS_SECURE(eflags & ~PSL_RF, regs->tf_eflags & ~PSL_RF)) {
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.
*/
#define CS_SECURE(cs) (ISPL(cs) == SEL_UPL)
if (!CS_SECURE(context->sc_cs)) {
trapsignal(p, SIGBUS, T_PROTFLT);
return(EINVAL);
}
linux_to_bsd_sigset(&uc.uc_sigmask, &p->p_sigmask);
SIG_CANTMASK(p->p_sigmask);
/*
* Restore signal context
*/
/* %gs was restored by the trampoline. */
regs->tf_fs = context->sc_fs;
regs->tf_es = context->sc_es;
regs->tf_ds = context->sc_ds;
regs->tf_edi = context->sc_edi;
regs->tf_esi = context->sc_esi;
regs->tf_ebp = context->sc_ebp;
regs->tf_ebx = context->sc_ebx;
regs->tf_edx = context->sc_edx;
regs->tf_ecx = context->sc_ecx;
regs->tf_eax = context->sc_eax;
regs->tf_eip = context->sc_eip;
regs->tf_cs = context->sc_cs;
regs->tf_eflags = eflags;
regs->tf_esp = context->sc_esp_at_signal;
regs->tf_ss = context->sc_ss;
/*
* call sigaltstack & ignore results..
*/
ss = stackgap_alloc(&sg, sizeof(stack_t));
lss = &uc.uc_stack;
ss->ss_sp = lss->ss_sp;
ss->ss_size = lss->ss_size;
ss->ss_flags = linux_to_bsd_sigaltstack(lss->ss_flags);
#ifdef DEBUG
printf("Linux-emul(%ld): rt_sigret flags: 0x%x, sp: %p, ss: 0x%x, mask: 0x%x\n",
(long)p->p_pid, ss->ss_flags, ss->ss_sp, ss->ss_size, context->sc_mask);
#endif
sasargs.ss = ss;
sasargs.oss = NULL;
(void) sigaltstack(p, &sasargs);
return (EJUSTRETURN);
}
static void
linux_prepsyscall(struct trapframe *tf, int *args, u_int *code, caddr_t *params)
{
args[0] = tf->tf_ebx;
args[1] = tf->tf_ecx;
args[2] = tf->tf_edx;
args[3] = tf->tf_esi;
args[4] = tf->tf_edi;
*params = NULL; /* no copyin */
}
/*
* If a linux binary is exec'ing something, try this image activator
* first. We override standard shell script execution in order to
* be able to modify the interpreter path. We only do this if a linux
* binary is doing the exec, so we do not create an EXEC module for it.
*/
static int exec_linux_imgact_try __P((struct image_params *iparams));
static int
exec_linux_imgact_try(imgp)
struct image_params *imgp;
{
const char *head = (const char *)imgp->image_header;
int error = -1;
/*
* The interpreter for shell scripts run from a linux binary needs
* to be located in /compat/linux if possible in order to recursively
* maintain linux path emulation.
*/
if (((const short *)head)[0] == SHELLMAGIC) {
/*
* Run our normal shell image activator. If it succeeds attempt
* to use the alternate path for the interpreter. If an alternate
* path is found, use our stringspace to store it.
*/
if ((error = exec_shell_imgact(imgp)) == 0) {
char *rpath = NULL;
linux_emul_find(imgp->proc, NULL, linux_emul_path,
imgp->interpreter_name, &rpath, 0);
if (rpath != imgp->interpreter_name) {
int len = strlen(rpath) + 1;
if (len <= MAXSHELLCMDLEN) {
memcpy(imgp->interpreter_name, rpath, len);
}
free(rpath, M_TEMP);
}
}
}
return(error);
}
struct sysentvec linux_sysvec = {
LINUX_SYS_MAXSYSCALL,
linux_sysent,
0xff,
LINUX_SIGTBLSZ,
bsd_to_linux_signal,
ELAST + 1,
bsd_to_linux_errno,
translate_traps,
linux_fixup,
linux_sendsig,
linux_sigcode,
&linux_szsigcode,
linux_prepsyscall,
"Linux a.out",
aout_coredump,
exec_linux_imgact_try,
LINUX_MINSIGSTKSZ
};
struct sysentvec elf_linux_sysvec = {
LINUX_SYS_MAXSYSCALL,
linux_sysent,
0xff,
LINUX_SIGTBLSZ,
bsd_to_linux_signal,
ELAST + 1,
bsd_to_linux_errno,
translate_traps,
elf_linux_fixup,
linux_sendsig,
linux_sigcode,
&linux_szsigcode,
linux_prepsyscall,
"Linux ELF",
elf_coredump,
exec_linux_imgact_try,
LINUX_MINSIGSTKSZ
};
static Elf32_Brandinfo linux_brand = {
ELFOSABI_LINUX,
"/compat/linux",
"/lib/ld-linux.so.1",
&elf_linux_sysvec
};
static Elf32_Brandinfo linux_glibc2brand = {
ELFOSABI_LINUX,
"/compat/linux",
"/lib/ld-linux.so.2",
&elf_linux_sysvec
};
Elf32_Brandinfo *linux_brandlist[] = {
&linux_brand,
&linux_glibc2brand,
NULL
};
static int
linux_elf_modevent(module_t mod, int type, void *data)
{
Elf32_Brandinfo **brandinfo;
int error;
error = 0;
switch(type) {
case MOD_LOAD:
for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
++brandinfo)
if (elf_insert_brand_entry(*brandinfo) < 0)
error = EINVAL;
if (error == 0) {
linux_ioctl_register_handlers(
&linux_ioctl_handler_set);
if (bootverbose)
printf("Linux ELF exec handler installed\n");
} else
printf("cannot insert Linux ELF brand handler\n");
break;
case MOD_UNLOAD:
for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
++brandinfo)
if (elf_brand_inuse(*brandinfo))
error = EBUSY;
if (error == 0) {
for (brandinfo = &linux_brandlist[0];
*brandinfo != NULL; ++brandinfo)
if (elf_remove_brand_entry(*brandinfo) < 0)
error = EINVAL;
}
if (error == 0) {
linux_ioctl_unregister_handlers(
&linux_ioctl_handler_set);
if (bootverbose)
printf("Linux ELF exec handler removed\n");
} else
printf("Could not deinstall ELF interpreter entry\n");
break;
default:
break;
}
return error;
}
static moduledata_t linux_elf_mod = {
"linuxelf",
linux_elf_modevent,
0
};
DECLARE_MODULE(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
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