arch/x86/ia32/ptrace32.c

   1 /*
   2  * 32bit ptrace for x86-64.
   3  *
   4  * Copyright 2001,2002 Andi Kleen, SuSE Labs.
   5  * Some parts copied from arch/i386/kernel/ptrace.c. See that file for earlier
   6  * copyright.
   7  *
   8  * This allows to access 64bit processes too; but there is no way to
   9  * see the extended register contents.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/stddef.h>
  14 #include <linux/sched.h>
  15 #include <linux/syscalls.h>
  16 #include <linux/unistd.h>
  17 #include <linux/mm.h>
  18 #include <linux/err.h>
  19 #include <linux/ptrace.h>
  20 #include <asm/ptrace.h>
  21 #include <asm/compat.h>
  22 #include <asm/uaccess.h>
  23 #include <asm/user32.h>
  24 #include <asm/user.h>
  25 #include <asm/errno.h>
  26 #include <asm/debugreg.h>
  27 #include <asm/i387.h>
  28 #include <asm/fpu32.h>
  29 #include <asm/ia32.h>
  30
  31 /*
  32  * Determines which flags the user has access to [1 = access, 0 = no access].
  33  * Prohibits changing ID(21), VIP(20), VIF(19), VM(17), IOPL(12-13), IF(9).
  34  * Also masks reserved bits (31-22, 15, 5, 3, 1).
  35  */
  36 #define FLAG_MASK 0x54dd5UL
  37
  38 #define R32(l,q)                                                        \
  39         case offsetof(struct user32, regs.l):                           \
  40                 stack[offsetof(struct pt_regs, q) / 8] = val; break
  41
  42 static int putreg32(struct task_struct *child, unsigned regno, u32 val)
  43 {
  44         __u64 *stack = (__u64 *)task_pt_regs(child);
  45
  46         switch (regno) {
  47         case offsetof(struct user32, regs.fs):
  48                 if (val && (val & 3) != 3)
  49                         return -EIO;
  50                 child->thread.fsindex = val & 0xffff;
  51                 break;
  52         case offsetof(struct user32, regs.gs):
  53                 if (val && (val & 3) != 3)
  54                         return -EIO;
  55                 child->thread.gsindex = val & 0xffff;
  56                 break;
  57         case offsetof(struct user32, regs.ds):
  58                 if (val && (val & 3) != 3)
  59                         return -EIO;
  60                 child->thread.ds = val & 0xffff;
  61                 break;
  62         case offsetof(struct user32, regs.es):
  63                 child->thread.es = val & 0xffff;
  64                 break;
  65         case offsetof(struct user32, regs.ss):
  66                 if ((val & 3) != 3)
  67                         return -EIO;
  68                 stack[offsetof(struct pt_regs, ss)/8] = val & 0xffff;
  69                 break;
  70         case offsetof(struct user32, regs.cs):
  71                 if ((val & 3) != 3)
  72                         return -EIO;
  73                 stack[offsetof(struct pt_regs, cs)/8] = val & 0xffff;
  74                 break;
  75
  76         R32(ebx, bx);
  77         R32(ecx, cx);
  78         R32(edx, dx);
  79         R32(edi, di);
  80         R32(esi, si);
  81         R32(ebp, bp);
  82         R32(eax, ax);
  83         R32(orig_eax, orig_ax);
  84         R32(eip, ip);
  85         R32(esp, sp);
  86
  87         case offsetof(struct user32, regs.eflags): {
  88                 __u64 *flags = &stack[offsetof(struct pt_regs, flags)/8];
  89
  90                 val &= FLAG_MASK;
  91                 /*
  92                  * If the user value contains TF, mark that
  93                  * it was not "us" (the debugger) that set it.
  94                  * If not, make sure it stays set if we had.
  95                  */
  96                 if (val & X86_EFLAGS_TF)
  97                         clear_tsk_thread_flag(child, TIF_FORCED_TF);
  98                 else if (test_tsk_thread_flag(child, TIF_FORCED_TF))
  99                         val |= X86_EFLAGS_TF;
 100                 *flags = val | (*flags & ~FLAG_MASK);
 101                 break;
 102         }
 103
 104         case offsetof(struct user32, u_debugreg[0]) ...
 105                 offsetof(struct user32, u_debugreg[7]):
 106                 regno -= offsetof(struct user32, u_debugreg[0]);
 107                 return ptrace_set_debugreg(child, regno / 4, val);
 108
 109         default:
 110                 if (regno > sizeof(struct user32) || (regno & 3))
 111                         return -EIO;
 112
 113                 /*
 114                  * Other dummy fields in the virtual user structure
 115                  * are ignored
 116                  */
 117                 break;
 118         }
 119         return 0;
 120 }
 121
 122 #undef R32
 123
 124 #define R32(l,q)                                                        \
 125         case offsetof(struct user32, regs.l):                           \
 126                 *val = stack[offsetof(struct pt_regs, q)/8]; break
 127
 128 static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
 129 {
 130         __u64 *stack = (__u64 *)task_pt_regs(child);
 131
 132         switch (regno) {
 133         case offsetof(struct user32, regs.fs):
 134                 *val = child->thread.fsindex;
 135                 break;
 136         case offsetof(struct user32, regs.gs):
 137                 *val = child->thread.gsindex;
 138                 break;
 139         case offsetof(struct user32, regs.ds):
 140                 *val = child->thread.ds;
 141                 break;
 142         case offsetof(struct user32, regs.es):
 143                 *val = child->thread.es;
 144                 break;
 145
 146         R32(cs, cs);
 147         R32(ss, ss);
 148         R32(ebx, bx);
 149         R32(ecx, cx);
 150         R32(edx, dx);
 151         R32(edi, di);
 152         R32(esi, si);
 153         R32(ebp, bp);
 154         R32(eax, ax);
 155         R32(orig_eax, orig_ax);
 156         R32(eip, ip);
 157         R32(esp, sp);
 158
 159         case offsetof(struct user32, regs.eflags):
 160                 /*
 161                  * If the debugger set TF, hide it from the readout.
 162                  */
 163                 *val = stack[offsetof(struct pt_regs, flags)/8];
 164                 if (test_tsk_thread_flag(child, TIF_FORCED_TF))
 165                         *val &= ~X86_EFLAGS_TF;
 166                 break;
 167
 168         case offsetof(struct user32, u_debugreg[0]) ...
 169                 offsetof(struct user32, u_debugreg[7]):
 170                 regno -= offsetof(struct user32, u_debugreg[0]);
 171                 *val = ptrace_get_debugreg(child, regno / 4);
 172                 break;
 173
 174         default:
 175                 if (regno > sizeof(struct user32) || (regno & 3))
 176                         return -EIO;
 177
 178                 /*
 179                  * Other dummy fields in the virtual user structure
 180                  * are ignored
 181                  */
 182                 *val = 0;
 183                 break;
 184         }
 185         return 0;
 186 }
 187
 188 #undef R32
 189
 190 static long ptrace32_siginfo(unsigned request, u32 pid, u32 addr, u32 data)
 191 {
 192         siginfo_t __user *si = compat_alloc_user_space(sizeof(siginfo_t));
 193         compat_siginfo_t __user *si32 = compat_ptr(data);
 194         siginfo_t ssi;
 195         int ret;
 196
 197         if (request == PTRACE_SETSIGINFO) {
 198                 memset(&ssi, 0, sizeof(siginfo_t));
 199                 ret = copy_siginfo_from_user32(&ssi, si32);
 200                 if (ret)
 201                         return ret;
 202                 if (copy_to_user(si, &ssi, sizeof(siginfo_t)))
 203                         return -EFAULT;
 204         }
 205         ret = sys_ptrace(request, pid, addr, (unsigned long)si);
 206         if (ret)
 207                 return ret;
 208         if (request == PTRACE_GETSIGINFO) {
 209                 if (copy_from_user(&ssi, si, sizeof(siginfo_t)))
 210                         return -EFAULT;
 211                 ret = copy_siginfo_to_user32(si32, &ssi);
 212         }
 213         return ret;
 214 }
 215
 216 asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
 217 {
 218         struct task_struct *child;
 219         struct pt_regs *childregs;
 220         void __user *datap = compat_ptr(data);
 221         int ret;
 222         __u32 val;
 223
 224         switch (request) {
 225         case PTRACE_TRACEME:
 226         case PTRACE_ATTACH:
 227         case PTRACE_KILL:
 228         case PTRACE_CONT:
 229         case PTRACE_SINGLESTEP:
 230         case PTRACE_SINGLEBLOCK:
 231         case PTRACE_DETACH:
 232         case PTRACE_SYSCALL:
 233         case PTRACE_OLDSETOPTIONS:
 234         case PTRACE_SETOPTIONS:
 235         case PTRACE_SET_THREAD_AREA:
 236         case PTRACE_GET_THREAD_AREA:
 237                 return sys_ptrace(request, pid, addr, data);
 238
 239         default:
 240                 return -EINVAL;
 241
 242         case PTRACE_PEEKTEXT:
 243         case PTRACE_PEEKDATA:
 244         case PTRACE_POKEDATA:
 245         case PTRACE_POKETEXT:
 246         case PTRACE_POKEUSR:
 247         case PTRACE_PEEKUSR:
 248         case PTRACE_GETREGS:
 249         case PTRACE_SETREGS:
 250         case PTRACE_SETFPREGS:
 251         case PTRACE_GETFPREGS:
 252         case PTRACE_SETFPXREGS:
 253         case PTRACE_GETFPXREGS:
 254         case PTRACE_GETEVENTMSG:
 255                 break;
 256
 257         case PTRACE_SETSIGINFO:
 258         case PTRACE_GETSIGINFO:
 259                 return ptrace32_siginfo(request, pid, addr, data);
 260         }
 261
 262         child = ptrace_get_task_struct(pid);
 263         if (IS_ERR(child))
 264                 return PTR_ERR(child);
 265
 266         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 267         if (ret < 0)
 268                 goto out;
 269
 270         childregs = task_pt_regs(child);
 271
 272         switch (request) {
 273         case PTRACE_PEEKDATA:
 274         case PTRACE_PEEKTEXT:
 275                 ret = 0;
 276                 if (access_process_vm(child, addr, &val, sizeof(u32), 0) !=
 277                     sizeof(u32))
 278                         ret = -EIO;
 279                 else
 280                         ret = put_user(val, (unsigned int __user *)datap);
 281                 break;
 282
 283         case PTRACE_POKEDATA:
 284         case PTRACE_POKETEXT:
 285                 ret = 0;
 286                 if (access_process_vm(child, addr, &data, sizeof(u32), 1) !=
 287                     sizeof(u32))
 288                         ret = -EIO;
 289                 break;
 290
 291         case PTRACE_PEEKUSR:
 292                 ret = getreg32(child, addr, &val);
 293                 if (ret == 0)
 294                         ret = put_user(val, (__u32 __user *)datap);
 295                 break;
 296
 297         case PTRACE_POKEUSR:
 298                 ret = putreg32(child, addr, data);
 299                 break;
 300
 301         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 302                 int i;
 303
 304                 if (!access_ok(VERIFY_WRITE, datap, 16*4)) {
 305                         ret = -EIO;
 306                         break;
 307                 }
 308                 ret = 0;
 309                 for (i = 0; i <= 16*4; i += sizeof(__u32)) {
 310                         getreg32(child, i, &val);
 311                         ret |= __put_user(val, (u32 __user *)datap);
 312                         datap += sizeof(u32);
 313                 }
 314                 break;
 315         }
 316
 317         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 318                 unsigned long tmp;
 319                 int i;
 320
 321                 if (!access_ok(VERIFY_READ, datap, 16*4)) {
 322                         ret = -EIO;
 323                         break;
 324                 }
 325                 ret = 0;
 326                 for (i = 0; i <= 16*4; i += sizeof(u32)) {
 327                         ret |= __get_user(tmp, (u32 __user *)datap);
 328                         putreg32(child, i, tmp);
 329                         datap += sizeof(u32);
 330                 }
 331                 break;
 332         }
 333
 334         case PTRACE_GETFPREGS:
 335                 ret = -EIO;
 336                 if (!access_ok(VERIFY_READ, compat_ptr(data),
 337                                sizeof(struct user_i387_struct)))
 338                         break;
 339                 save_i387_ia32(child, datap, childregs, 1);
 340                 ret = 0;
 341                         break;
 342
 343         case PTRACE_SETFPREGS:
 344                 ret = -EIO;
 345                 if (!access_ok(VERIFY_WRITE, datap,
 346                                sizeof(struct user_i387_struct)))
 347                         break;
 348                 ret = 0;
 349                 /* don't check EFAULT to be bug-to-bug compatible to i386 */
 350                 restore_i387_ia32(child, datap, 1);
 351                 break;
 352
 353         case PTRACE_GETFPXREGS: {
 354                 struct user32_fxsr_struct __user *u = datap;
 355
 356                 init_fpu(child);
 357                 ret = -EIO;
 358                 if (!access_ok(VERIFY_WRITE, u, sizeof(*u)))
 359                         break;
 360                         ret = -EFAULT;
 361                 if (__copy_to_user(u, &child->thread.i387.fxsave, sizeof(*u)))
 362                         break;
 363                 ret = __put_user(childregs->cs, &u->fcs);
 364                 ret |= __put_user(child->thread.ds, &u->fos);
 365                 break;
 366         }
 367         case PTRACE_SETFPXREGS: {
 368                 struct user32_fxsr_struct __user *u = datap;
 369
 370                 unlazy_fpu(child);
 371                 ret = -EIO;
 372                 if (!access_ok(VERIFY_READ, u, sizeof(*u)))
 373                         break;
 374                 /*
 375                  * no checking to be bug-to-bug compatible with i386.
 376                  * but silence warning
 377                  */
 378                 if (__copy_from_user(&child->thread.i387.fxsave, u, sizeof(*u)))
 379                         ;
 380                 set_stopped_child_used_math(child);
 381                 child->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
 382                 ret = 0;
 383                 break;
 384         }
 385
 386         case PTRACE_GETEVENTMSG:
 387                 ret = put_user(child->ptrace_message,
 388                                (unsigned int __user *)compat_ptr(data));
 389                 break;
 390
 391         default:
 392                 BUG();
 393         }
 394
 395  out:
 396         put_task_struct(child);
 397         return ret;
 398 }