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ptrace32.c

/* 
 * 32bit ptrace for x86-64.
 *
 * Copyright 2001,2002 Andi Kleen, SuSE Labs.
 * Some parts copied from arch/i386/kernel/ptrace.c. See that file for earlier 
 * copyright.
 * 
 * This allows to access 64bit processes too; but there is no way to see the extended 
 * register contents.
 */ 

#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/ptrace.h>
#include <asm/ptrace.h>
#include <asm/compat.h>
#include <asm/uaccess.h>
#include <asm/user32.h>
#include <asm/user.h>
#include <asm/errno.h>
#include <asm/debugreg.h>
#include <asm/i387.h>
#include <asm/fpu32.h>
#include <asm/ia32.h>

/*
 * Determines which flags the user has access to [1 = access, 0 = no access].
 * Prohibits changing ID(21), VIP(20), VIF(19), VM(17), IOPL(12-13), IF(9).
 * Also masks reserved bits (31-22, 15, 5, 3, 1).
 */
#define FLAG_MASK 0x54dd5UL

#define R32(l,q) \
      case offsetof(struct user32, regs.l): stack[offsetof(struct pt_regs, q)/8] = val; break

static int putreg32(struct task_struct *child, unsigned regno, u32 val)
{
      int i;
      __u64 *stack = (__u64 *)task_pt_regs(child);

      switch (regno) {
      case offsetof(struct user32, regs.fs):
            if (val && (val & 3) != 3) return -EIO; 
            child->thread.fsindex = val & 0xffff;
            break;
      case offsetof(struct user32, regs.gs):
            if (val && (val & 3) != 3) return -EIO; 
            child->thread.gsindex = val & 0xffff;
            break;
      case offsetof(struct user32, regs.ds):
            if (val && (val & 3) != 3) return -EIO; 
            child->thread.ds = val & 0xffff;
            break;
      case offsetof(struct user32, regs.es):
            child->thread.es = val & 0xffff;
            break;
      case offsetof(struct user32, regs.ss): 
            if ((val & 3) != 3) return -EIO;
            stack[offsetof(struct pt_regs, ss)/8] = val & 0xffff;
            break;
      case offsetof(struct user32, regs.cs): 
            if ((val & 3) != 3) return -EIO;
            stack[offsetof(struct pt_regs, cs)/8] = val & 0xffff;
            break;

      R32(ebx, rbx); 
      R32(ecx, rcx);
      R32(edx, rdx);
      R32(edi, rdi);
      R32(esi, rsi);
      R32(ebp, rbp);
      R32(eax, rax);
      R32(orig_eax, orig_rax);
      R32(eip, rip);
      R32(esp, rsp);

      case offsetof(struct user32, regs.eflags): {
            __u64 *flags = &stack[offsetof(struct pt_regs, eflags)/8];
            val &= FLAG_MASK;
            *flags = val | (*flags & ~FLAG_MASK);
            break;
      }

      case offsetof(struct user32, u_debugreg[4]): 
      case offsetof(struct user32, u_debugreg[5]):
            return -EIO;

      case offsetof(struct user32, u_debugreg[0]):
            child->thread.debugreg0 = val;
            break;

      case offsetof(struct user32, u_debugreg[1]):
            child->thread.debugreg1 = val;
            break;

      case offsetof(struct user32, u_debugreg[2]):
            child->thread.debugreg2 = val;
            break;

      case offsetof(struct user32, u_debugreg[3]):
            child->thread.debugreg3 = val;
            break;

      case offsetof(struct user32, u_debugreg[6]):
            child->thread.debugreg6 = val;
            break; 

      case offsetof(struct user32, u_debugreg[7]):
            val &= ~DR_CONTROL_RESERVED;
            /* See arch/i386/kernel/ptrace.c for an explanation of
             * this awkward check.*/
            for(i=0; i<4; i++)
                  if ((0x5454 >> ((val >> (16 + 4*i)) & 0xf)) & 1)
                         return -EIO;
            child->thread.debugreg7 = val; 
            if (val)
                  set_tsk_thread_flag(child, TIF_DEBUG);
            else
                  clear_tsk_thread_flag(child, TIF_DEBUG);
            break; 
                
      default:
            if (regno > sizeof(struct user32) || (regno & 3))
                  return -EIO;
             
            /* Other dummy fields in the virtual user structure are ignored */ 
            break;            
      }
      return 0;
}

#undef R32

#define R32(l,q) \
      case offsetof(struct user32, regs.l): *val = stack[offsetof(struct pt_regs, q)/8]; break

static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
{
      __u64 *stack = (__u64 *)task_pt_regs(child);

      switch (regno) {
      case offsetof(struct user32, regs.fs):
              *val = child->thread.fsindex;
            break;
      case offsetof(struct user32, regs.gs):
            *val = child->thread.gsindex;
            break;
      case offsetof(struct user32, regs.ds):
            *val = child->thread.ds;
            break;
      case offsetof(struct user32, regs.es):
            *val = child->thread.es;
            break;

      R32(cs, cs);
      R32(ss, ss);
      R32(ebx, rbx); 
      R32(ecx, rcx);
      R32(edx, rdx);
      R32(edi, rdi);
      R32(esi, rsi);
      R32(ebp, rbp);
      R32(eax, rax);
      R32(orig_eax, orig_rax);
      R32(eip, rip);
      R32(eflags, eflags);
      R32(esp, rsp);

      case offsetof(struct user32, u_debugreg[0]): 
            *val = child->thread.debugreg0; 
            break; 
      case offsetof(struct user32, u_debugreg[1]): 
            *val = child->thread.debugreg1; 
            break; 
      case offsetof(struct user32, u_debugreg[2]): 
            *val = child->thread.debugreg2; 
            break; 
      case offsetof(struct user32, u_debugreg[3]): 
            *val = child->thread.debugreg3; 
            break; 
      case offsetof(struct user32, u_debugreg[6]): 
            *val = child->thread.debugreg6; 
            break; 
      case offsetof(struct user32, u_debugreg[7]): 
            *val = child->thread.debugreg7; 
            break; 
                
      default:
            if (regno > sizeof(struct user32) || (regno & 3))
                  return -EIO;

            /* Other dummy fields in the virtual user structure are ignored */ 
            *val = 0;
            break;            
      }
      return 0;
}

#undef R32

static long ptrace32_siginfo(unsigned request, u32 pid, u32 addr, u32 data)
{
      int ret;
      compat_siginfo_t __user *si32 = compat_ptr(data);
      siginfo_t ssi; 
      siginfo_t __user *si = compat_alloc_user_space(sizeof(siginfo_t));
      if (request == PTRACE_SETSIGINFO) {
            memset(&ssi, 0, sizeof(siginfo_t));
            ret = copy_siginfo_from_user32(&ssi, si32);
            if (ret)
                  return ret;
            if (copy_to_user(si, &ssi, sizeof(siginfo_t)))
                  return -EFAULT;
      }
      ret = sys_ptrace(request, pid, addr, (unsigned long)si);
      if (ret)
            return ret;
      if (request == PTRACE_GETSIGINFO) {
            if (copy_from_user(&ssi, si, sizeof(siginfo_t)))
                  return -EFAULT;
            ret = copy_siginfo_to_user32(si32, &ssi);
      }
      return ret;
}

asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
{
      struct task_struct *child;
      struct pt_regs *childregs; 
      void __user *datap = compat_ptr(data);
      int ret;
      __u32 val;

      switch (request) { 
      case PTRACE_TRACEME:
      case PTRACE_ATTACH:
      case PTRACE_KILL:
      case PTRACE_CONT:
      case PTRACE_SINGLESTEP:
      case PTRACE_DETACH:
      case PTRACE_SYSCALL:
      case PTRACE_OLDSETOPTIONS:
      case PTRACE_SETOPTIONS:
      case PTRACE_SET_THREAD_AREA:
      case PTRACE_GET_THREAD_AREA:
            return sys_ptrace(request, pid, addr, data); 

      default:
            return -EINVAL;

      case PTRACE_PEEKTEXT:
      case PTRACE_PEEKDATA:
      case PTRACE_POKEDATA:
      case PTRACE_POKETEXT:
      case PTRACE_POKEUSR:       
      case PTRACE_PEEKUSR:
      case PTRACE_GETREGS:
      case PTRACE_SETREGS:
      case PTRACE_SETFPREGS:
      case PTRACE_GETFPREGS:
      case PTRACE_SETFPXREGS:
      case PTRACE_GETFPXREGS:
      case PTRACE_GETEVENTMSG:
            break;

      case PTRACE_SETSIGINFO:
      case PTRACE_GETSIGINFO:
            return ptrace32_siginfo(request, pid, addr, data);
      }

      child = ptrace_get_task_struct(pid);
      if (IS_ERR(child))
            return PTR_ERR(child);

      ret = ptrace_check_attach(child, request == PTRACE_KILL);
      if (ret < 0)
            goto out;

      childregs = task_pt_regs(child);

      switch (request) {
      case PTRACE_PEEKDATA:
      case PTRACE_PEEKTEXT:
            ret = 0;
            if (access_process_vm(child, addr, &val, sizeof(u32), 0)!=sizeof(u32))
                  ret = -EIO;
            else
                  ret = put_user(val, (unsigned int __user *)datap); 
            break; 

      case PTRACE_POKEDATA:
      case PTRACE_POKETEXT:
            ret = 0;
            if (access_process_vm(child, addr, &data, sizeof(u32), 1)!=sizeof(u32))
                  ret = -EIO; 
            break;

      case PTRACE_PEEKUSR:
            ret = getreg32(child, addr, &val);
            if (ret == 0)
                  ret = put_user(val, (__u32 __user *)datap);
            break;

      case PTRACE_POKEUSR:
            ret = putreg32(child, addr, data);
            break;

      case PTRACE_GETREGS: { /* Get all gp regs from the child. */
            int i;
            if (!access_ok(VERIFY_WRITE, datap, 16*4)) {
                  ret = -EIO;
                  break;
            }
            ret = 0;
            for ( i = 0; i <= 16*4 ; i += sizeof(__u32) ) {
                  getreg32(child, i, &val);
                  ret |= __put_user(val,(u32 __user *)datap);
                  datap += sizeof(u32);
            }
            break;
      }

      case PTRACE_SETREGS: { /* Set all gp regs in the child. */
            unsigned long tmp;
            int i;
            if (!access_ok(VERIFY_READ, datap, 16*4)) {
                  ret = -EIO;
                  break;
            }
            ret = 0; 
            for ( i = 0; i <= 16*4; i += sizeof(u32) ) {
                  ret |= __get_user(tmp, (u32 __user *)datap);
                  putreg32(child, i, tmp);
                  datap += sizeof(u32);
            }
            break;
      }

      case PTRACE_GETFPREGS:
            ret = -EIO; 
            if (!access_ok(VERIFY_READ, compat_ptr(data), 
                         sizeof(struct user_i387_struct)))
                  break;
            save_i387_ia32(child, datap, childregs, 1);
            ret = 0; 
                  break;

      case PTRACE_SETFPREGS:
            ret = -EIO;
            if (!access_ok(VERIFY_WRITE, datap, 
                         sizeof(struct user_i387_struct)))
                  break;
            ret = 0;
            /* don't check EFAULT to be bug-to-bug compatible to i386 */
            restore_i387_ia32(child, datap, 1);
            break;

      case PTRACE_GETFPXREGS: { 
            struct user32_fxsr_struct __user *u = datap;
            init_fpu(child); 
            ret = -EIO;
            if (!access_ok(VERIFY_WRITE, u, sizeof(*u)))
                  break;
                  ret = -EFAULT;
            if (__copy_to_user(u, &child->thread.i387.fxsave, sizeof(*u)))
                  break;
            ret = __put_user(childregs->cs, &u->fcs);
            ret |= __put_user(child->thread.ds, &u->fos); 
            break; 
      } 
      case PTRACE_SETFPXREGS: { 
            struct user32_fxsr_struct __user *u = datap;
            unlazy_fpu(child);
            ret = -EIO;
            if (!access_ok(VERIFY_READ, u, sizeof(*u)))
                  break;
            /* no checking to be bug-to-bug compatible with i386. */
            /* but silence warning */
            if (__copy_from_user(&child->thread.i387.fxsave, u, sizeof(*u)))
                  ;
            set_stopped_child_used_math(child);
            child->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
            ret = 0; 
            break;
      }

      case PTRACE_GETEVENTMSG:
            ret = put_user(child->ptrace_message,(unsigned int __user *)compat_ptr(data));
            break;

      default:
            BUG();
      }

 out:
      put_task_struct(child);
      return ret;
}


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