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/* By Ross Biro 1/23/92 */
/*
* Pentium III FXSR, SSE support
* Gareth Hughes <gareth@valinux.com>, May 2000
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/audit.h>
#include <linux/seccomp.h>
#include <linux/signal.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/i387.h>
#include <asm/debugreg.h>
#include <asm/ldt.h>
#include <asm/desc.h>
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/*
* Determines which flags the user has access to [1 = access, 0 = no access].
* Prohibits changing ID(21), VIP(20), VIF(19), VM(17), NT(14), IOPL(12-13), IF(9).
* Also masks reserved bits (31-22, 15, 5, 3, 1).
*/
#define FLAG_MASK 0x00050dd5
/*
* Offset of eflags on child stack..
*/
#define EFL_OFFSET offsetof(struct pt_regs, eflags)
static inline struct pt_regs *get_child_regs(struct task_struct *task)
{
void *stack_top = (void *)task->thread.esp0;
return stack_top - sizeof(struct pt_regs);
}
/*
* This routine will get a word off of the processes privileged stack.
* the offset is bytes into the pt_regs structure on the stack.
* This routine assumes that all the privileged stacks are in our
* data space.
*/
static inline int get_stack_long(struct task_struct *task, int offset)
{
unsigned char *stack;
stack = (unsigned char *)task->thread.esp0 - sizeof(struct pt_regs);
stack += offset;
return (*((int *)stack));
}
/*
* This routine will put a word on the processes privileged stack.
* the offset is bytes into the pt_regs structure on the stack.
* This routine assumes that all the privileged stacks are in our
* data space.
*/
static inline int put_stack_long(struct task_struct *task, int offset,
unsigned long data)
{
unsigned char * stack;
stack = (unsigned char *)task->thread.esp0 - sizeof(struct pt_regs);
stack += offset;
*(unsigned long *) stack = data;
return 0;
}
static int putreg(struct task_struct *child,
unsigned long regno, unsigned long value)
{
switch (regno >> 2) {
case GS:
if (value && (value & 3) != 3)
return -EIO;
child->thread.gs = value;
return 0;
case DS:
case ES:
case FS:
if (value && (value & 3) != 3)
return -EIO;
value &= 0xffff;
break;
case SS:
case CS:
if ((value & 3) != 3)
return -EIO;
value &= 0xffff;
break;
case EFL:
value &= FLAG_MASK;
/*
* If the user value contains TF, mark that
* it was not "us" (the debugger) that set it.
* If not, make sure it stays set if we had.
*/
if (value & X86_EFLAGS_TF)
clear_tsk_thread_flag(child, TIF_FORCED_TF);
else if (test_tsk_thread_flag(child, TIF_FORCED_TF))
value |= X86_EFLAGS_TF;
value |= get_stack_long(child, EFL_OFFSET) & ~FLAG_MASK;
break;
}
if (regno > FS*4)
regno -= 1*4;
put_stack_long(child, regno, value);
return 0;
}
static unsigned long getreg(struct task_struct *child,
unsigned long regno)
{
unsigned long retval = ~0UL;
switch (regno >> 2) {
case EFL:
/*
* If the debugger set TF, hide it from the readout.
*/
retval = get_stack_long(child, EFL_OFFSET);
if (test_tsk_thread_flag(child, TIF_FORCED_TF))
retval &= ~X86_EFLAGS_TF;
break;
case GS:
retval = child->thread.gs;
break;
case DS:
case ES:
case FS:
case SS:
case CS:
retval = 0xffff;
/* fall through */
default:
if (regno > FS*4)
regno -= 1*4;
retval &= get_stack_long(child, regno);
}
return retval;
}
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure the single step bit is not set.
*/
void ptrace_disable(struct task_struct *child)
{
user_disable_single_step(child);
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
}
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
struct user * dummy = NULL;
int i, ret;
unsigned long __user *datap = (unsigned long __user *)data;
switch (request) {
/* when I and D space are separate, these will need to be fixed. */
case PTRACE_PEEKTEXT: /* read word at location addr. */
case PTRACE_PEEKDATA:
ret = generic_ptrace_peekdata(child, addr, data);
break;
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long tmp;
ret = -EIO;
if ((addr & 3) || addr < 0 ||
addr > sizeof(struct user) - 3)
break;
tmp = 0; /* Default return condition */
if(addr < FRAME_SIZE*sizeof(long))
tmp = getreg(child, addr);
if(addr >= (long) &dummy->u_debugreg[0] &&
addr <= (long) &dummy->u_debugreg[7]){
addr -= (long) &dummy->u_debugreg[0];
addr = addr >> 2;
tmp = child->thread.debugreg[addr];
}
ret = put_user(tmp, datap);
break;
}
/* when I and D space are separate, this will have to be fixed. */
case PTRACE_POKETEXT: /* write the word at location addr. */
case PTRACE_POKEDATA:
ret = generic_ptrace_pokedata(child, addr, data);
break;
case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
ret = -EIO;
if ((addr & 3) || addr < 0 ||
addr > sizeof(struct user) - 3)
break;
if (addr < FRAME_SIZE*sizeof(long)) {
ret = putreg(child, addr, data);
break;
}
/* We need to be very careful here. We implicitly
want to modify a portion of the task_struct, and we
have to be selective about what portions we allow someone
to modify. */
ret = -EIO;
if(addr >= (long) &dummy->u_debugreg[0] &&
addr <= (long) &dummy->u_debugreg[7]){
if(addr == (long) &dummy->u_debugreg[4]) break;
if(addr == (long) &dummy->u_debugreg[5]) break;
if(addr < (long) &dummy->u_debugreg[4] &&
((unsigned long) data) >= TASK_SIZE-3) break;
/* Sanity-check data. Take one half-byte at once with
* check = (val >> (16 + 4*i)) & 0xf. It contains the
* R/Wi and LENi bits; bits 0 and 1 are R/Wi, and bits
* 2 and 3 are LENi. Given a list of invalid values,
* we do mask |= 1 << invalid_value, so that
* (mask >> check) & 1 is a correct test for invalid
* values.
*
* R/Wi contains the type of the breakpoint /
* watchpoint, LENi contains the length of the watched
* data in the watchpoint case.
*
* The invalid values are:
* - LENi == 0x10 (undefined), so mask |= 0x0f00.
* - R/Wi == 0x10 (break on I/O reads or writes), so
* mask |= 0x4444.
* - R/Wi == 0x00 && LENi != 0x00, so we have mask |=
* 0x1110.
*
* Finally, mask = 0x0f00 | 0x4444 | 0x1110 == 0x5f54.
*
* See the Intel Manual "System Programming Guide",
* 15.2.4
*
* Note that LENi == 0x10 is defined on x86_64 in long
* mode (i.e. even for 32-bit userspace software, but
* 64-bit kernel), so the x86_64 mask value is 0x5454.
* See the AMD manual no. 24593 (AMD64 System
* Programming)*/
if(addr == (long) &dummy->u_debugreg[7]) {
data &= ~DR_CONTROL_RESERVED;
for(i=0; i<4; i++)
if ((0x5f54 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
goto out_tsk;
if (data)
set_tsk_thread_flag(child, TIF_DEBUG);
else
clear_tsk_thread_flag(child, TIF_DEBUG);
}
addr -= (long) &dummy->u_debugreg;
addr = addr >> 2;
child->thread.debugreg[addr] = data;
ret = 0;
}
break;
case PTRACE_SYSEMU: /* continue and stop at next syscall, which will not be executed */
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT: /* restart after signal. */
ret = -EIO;
if (!valid_signal(data))
break;
if (request == PTRACE_SYSEMU) {
set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
} else if (request == PTRACE_SYSCALL) {
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
} else {
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
}
child->exit_code = data;
/* make sure the single step bit is not set. */
user_disable_single_step(child);
wake_up_process(child);
ret = 0;
break;
/*
* make the child exit. Best I can do is send it a sigkill.
* perhaps it should be put in the status that it wants to
* exit.
*/
case PTRACE_KILL:
ret = 0;
if (child->exit_state == EXIT_ZOMBIE) /* already dead */
break;
child->exit_code = SIGKILL;
/* make sure the single step bit is not set. */
user_disable_single_step(child);
wake_up_process(child);
break;
case PTRACE_SYSEMU_SINGLESTEP: /* Same as SYSEMU, but singlestep if not syscall */
case PTRACE_SINGLESTEP: /* set the trap flag. */
ret = -EIO;
if (!valid_signal(data))
break;
if (request == PTRACE_SYSEMU_SINGLESTEP)
set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
else
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
user_enable_single_step(child);
child->exit_code = data;
/* give it a chance to run. */
wake_up_process(child);
ret = 0;
break;
case PTRACE_GETREGS: { /* Get all gp regs from the child. */
if (!access_ok(VERIFY_WRITE, datap, FRAME_SIZE*sizeof(long))) {
ret = -EIO;
break;
}
for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
__put_user(getreg(child, i), datap);
datap++;
}
ret = 0;
break;
}
case PTRACE_SETREGS: { /* Set all gp regs in the child. */
unsigned long tmp;
if (!access_ok(VERIFY_READ, datap, FRAME_SIZE*sizeof(long))) {
ret = -EIO;
break;
}
for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
__get_user(tmp, datap);
putreg(child, i, tmp);
datap++;
}
ret = 0;
break;
}
case PTRACE_GETFPREGS: { /* Get the child FPU state. */
if (!access_ok(VERIFY_WRITE, datap,
sizeof(struct user_i387_struct))) {
ret = -EIO;
break;
}
ret = 0;
if (!tsk_used_math(child))
init_fpu(child);
get_fpregs((struct user_i387_struct __user *)data, child);
break;
}
case PTRACE_SETFPREGS: { /* Set the child FPU state. */
if (!access_ok(VERIFY_READ, datap,
sizeof(struct user_i387_struct))) {
ret = -EIO;
break;
}
set_stopped_child_used_math(child);
set_fpregs(child, (struct user_i387_struct __user *)data);
ret = 0;
break;
}
case PTRACE_GETFPXREGS: { /* Get the child extended FPU state. */
if (!access_ok(VERIFY_WRITE, datap,
sizeof(struct user_fxsr_struct))) {
ret = -EIO;
break;
}
if (!tsk_used_math(child))
init_fpu(child);
ret = get_fpxregs((struct user_fxsr_struct __user *)data, child);
break;
}
case PTRACE_SETFPXREGS: { /* Set the child extended FPU state. */
if (!access_ok(VERIFY_READ, datap,
sizeof(struct user_fxsr_struct))) {
ret = -EIO;
break;
}
set_stopped_child_used_math(child);
ret = set_fpxregs(child, (struct user_fxsr_struct __user *)data);
break;
}
case PTRACE_GET_THREAD_AREA:
if (addr < 0)
return -EIO;
ret = do_get_thread_area(child, addr,
(struct user_desc __user *) data);
break;
case PTRACE_SET_THREAD_AREA:
if (addr < 0)
return -EIO;
ret = do_set_thread_area(child, addr,
(struct user_desc __user *) data, 0);
break;
default:
ret = ptrace_request(child, request, addr, data);
break;
}
out_tsk:
return ret;
}
void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
{
struct siginfo info;
tsk->thread.trap_no = 1;
tsk->thread.error_code = error_code;
memset(&info, 0, sizeof(info));
info.si_signo = SIGTRAP;
info.si_code = TRAP_BRKPT;
/* User-mode eip? */
info.si_addr = user_mode_vm(regs) ? (void __user *) regs->eip : NULL;
/* Send us the fake SIGTRAP */
force_sig_info(SIGTRAP, &info, tsk);
}
/* notification of system call entry/exit
* - triggered by current->work.syscall_trace
*/
__attribute__((regparm(3)))
int do_syscall_trace(struct pt_regs *regs, int entryexit)
{
int is_sysemu = test_thread_flag(TIF_SYSCALL_EMU);
/*
* With TIF_SYSCALL_EMU set we want to ignore TIF_SINGLESTEP for syscall
* interception
*/
int is_singlestep = !is_sysemu && test_thread_flag(TIF_SINGLESTEP);
int ret = 0;
/* do the secure computing check first */
if (!entryexit)
secure_computing(regs->orig_eax);
if (unlikely(current->audit_context)) {
if (entryexit)
audit_syscall_exit(AUDITSC_RESULT(regs->eax),
regs->eax);
/* Debug traps, when using PTRACE_SINGLESTEP, must be sent only
* on the syscall exit path. Normally, when TIF_SYSCALL_AUDIT is
* not used, entry.S will call us only on syscall exit, not
* entry; so when TIF_SYSCALL_AUDIT is used we must avoid
* calling send_sigtrap() on syscall entry.
*
* Note that when PTRACE_SYSEMU_SINGLESTEP is used,
* is_singlestep is false, despite his name, so we will still do
* the correct thing.
*/
else if (is_singlestep)
goto out;
}
if (!(current->ptrace & PT_PTRACED))
goto out;
/* If a process stops on the 1st tracepoint with SYSCALL_TRACE
* and then is resumed with SYSEMU_SINGLESTEP, it will come in
* here. We have to check this and return */
if (is_sysemu && entryexit)
return 0;
/* Fake a debug trap */
if (is_singlestep)
send_sigtrap(current, regs, 0);
if (!test_thread_flag(TIF_SYSCALL_TRACE) && !is_sysemu)
goto out;
/* the 0x80 provides a way for the tracing parent to distinguish
between a syscall stop and SIGTRAP delivery */
/* Note that the debugger could change the result of test_thread_flag!*/
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80:0));
/*
* this isn't the same as continuing with a signal, but it will do
* for normal use. strace only continues with a signal if the
* stopping signal is not SIGTRAP. -brl
*/
if (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
ret = is_sysemu;
out:
if (unlikely(current->audit_context) && !entryexit)
audit_syscall_entry(AUDIT_ARCH_I386, regs->orig_eax,
regs->ebx, regs->ecx, regs->edx, regs->esi);
if (ret == 0)
return 0;
regs->orig_eax = -1; /* force skip of syscall restarting */
if (unlikely(current->audit_context))
audit_syscall_exit(AUDITSC_RESULT(regs->eax), regs->eax);
return 1;
}
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