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                 regs->q = val; break;
  41
  42 static int putreg32(struct task_struct *child, unsigned regno, u32 val)
  43 {
  44         struct pt_regs *regs = 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                 if (child == current)
  52                         loadsegment(fs, child->thread.fsindex);
  53                 break;
  54         case offsetof(struct user32, regs.gs):
  55                 if (val && (val & 3) != 3)
  56                         return -EIO;
  57                 child->thread.gsindex = val & 0xffff;
  58                 if (child == current)
  59                         load_gs_index(child->thread.gsindex);
  60                 break;
  61         case offsetof(struct user32, regs.ds):
  62                 if (val && (val & 3) != 3)
  63                         return -EIO;
  64                 child->thread.ds = val & 0xffff;
  65                 if (child == current)
  66                         loadsegment(ds, child->thread.ds);
  67                 break;
  68         case offsetof(struct user32, regs.es):
  69                 child->thread.es = val & 0xffff;
  70                 if (child == current)
  71                         loadsegment(es, child->thread.ds);
  72                 break;
  73         case offsetof(struct user32, regs.ss):
  74                 if ((val & 3) != 3)
  75                         return -EIO;
  76                 regs->ss = val & 0xffff;
  77                 break;
  78         case offsetof(struct user32, regs.cs):
  79                 if ((val & 3) != 3)
  80                         return -EIO;
  81                 regs->cs = val & 0xffff;
  82                 break;
  83
  84         R32(ebx, bx);
  85         R32(ecx, cx);
  86         R32(edx, dx);
  87         R32(edi, di);
  88         R32(esi, si);
  89         R32(ebp, bp);
  90         R32(eax, ax);
  91         R32(orig_eax, orig_ax);
  92         R32(eip, ip);
  93         R32(esp, sp);
  94
  95         case offsetof(struct user32, regs.eflags):
  96                 val &= FLAG_MASK;
  97                 /*
  98                  * If the user value contains TF, mark that
  99                  * it was not "us" (the debugger) that set it.
 100                  * If not, make sure it stays set if we had.
 101                  */
 102                 if (val & X86_EFLAGS_TF)
 103                         clear_tsk_thread_flag(child, TIF_FORCED_TF);
 104                 else if (test_tsk_thread_flag(child, TIF_FORCED_TF))
 105                         val |= X86_EFLAGS_TF;
 106                 regs->flags = val | (regs->flags & ~FLAG_MASK);
 107                 break;
 108
 109         case offsetof(struct user32, u_debugreg[0]) ...
 110                 offsetof(struct user32, u_debugreg[7]):
 111                 regno -= offsetof(struct user32, u_debugreg[0]);
 112                 return ptrace_set_debugreg(child, regno / 4, val);
 113
 114         default:
 115                 if (regno > sizeof(struct user32) || (regno & 3))
 116                         return -EIO;
 117
 118                 /*
 119                  * Other dummy fields in the virtual user structure
 120                  * are ignored
 121                  */
 122                 break;
 123         }
 124         return 0;
 125 }
 126
 127 #undef R32
 128
 129 #define R32(l,q)                                                        \
 130         case offsetof(struct user32, regs.l):                           \
 131                 *val = regs->q; break
 132
 133 static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
 134 {
 135         struct pt_regs *regs = task_pt_regs(child);
 136
 137         switch (regno) {
 138         case offsetof(struct user32, regs.fs):
 139                 *val = child->thread.fsindex;
 140                 if (child == current)
 141                         asm("movl %%fs,%0" : "=r" (*val));
 142                 break;
 143         case offsetof(struct user32, regs.gs):
 144                 *val = child->thread.gsindex;
 145                 if (child == current)
 146                         asm("movl %%gs,%0" : "=r" (*val));
 147                 break;
 148         case offsetof(struct user32, regs.ds):
 149                 *val = child->thread.ds;
 150                 if (child == current)
 151                         asm("movl %%ds,%0" : "=r" (*val));
 152                 break;
 153         case offsetof(struct user32, regs.es):
 154                 *val = child->thread.es;
 155                 if (child == current)
 156                         asm("movl %%es,%0" : "=r" (*val));
 157                 break;
 158
 159         R32(cs, cs);
 160         R32(ss, ss);
 161         R32(ebx, bx);
 162         R32(ecx, cx);
 163         R32(edx, dx);
 164         R32(edi, di);
 165         R32(esi, si);
 166         R32(ebp, bp);
 167         R32(eax, ax);
 168         R32(orig_eax, orig_ax);
 169         R32(eip, ip);
 170         R32(esp, sp);
 171
 172         case offsetof(struct user32, regs.eflags):
 173                 /*
 174                  * If the debugger set TF, hide it from the readout.
 175                  */
 176                 *val = regs->flags;
 177                 if (test_tsk_thread_flag(child, TIF_FORCED_TF))
 178                         *val &= ~X86_EFLAGS_TF;
 179                 break;
 180
 181         case offsetof(struct user32, u_debugreg[0]) ...
 182                 offsetof(struct user32, u_debugreg[7]):
 183                 regno -= offsetof(struct user32, u_debugreg[0]);
 184                 *val = ptrace_get_debugreg(child, regno / 4);
 185                 break;
 186
 187         default:
 188                 if (regno > sizeof(struct user32) || (regno & 3))
 189                         return -EIO;
 190
 191                 /*
 192                  * Other dummy fields in the virtual user structure
 193                  * are ignored
 194                  */
 195                 *val = 0;
 196                 break;
 197         }
 198         return 0;
 199 }
 200
 201 #undef R32
 202
 203 static long ptrace32_siginfo(unsigned request, u32 pid, u32 addr, u32 data)
 204 {
 205         siginfo_t __user *si = compat_alloc_user_space(sizeof(siginfo_t));
 206         compat_siginfo_t __user *si32 = compat_ptr(data);
 207         siginfo_t ssi;
 208         int ret;
 209
 210         if (request == PTRACE_SETSIGINFO) {
 211                 memset(&ssi, 0, sizeof(siginfo_t));
 212                 ret = copy_siginfo_from_user32(&ssi, si32);
 213                 if (ret)
 214                         return ret;
 215                 if (copy_to_user(si, &ssi, sizeof(siginfo_t)))
 216                         return -EFAULT;
 217         }
 218         ret = sys_ptrace(request, pid, addr, (unsigned long)si);
 219         if (ret)
 220                 return ret;
 221         if (request == PTRACE_GETSIGINFO) {
 222                 if (copy_from_user(&ssi, si, sizeof(siginfo_t)))
 223                         return -EFAULT;
 224                 ret = copy_siginfo_to_user32(si32, &ssi);
 225         }
 226         return ret;
 227 }
 228
 229 asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
 230 {
 231         struct task_struct *child;
 232         struct pt_regs *childregs;
 233         void __user *datap = compat_ptr(data);
 234         int ret;
 235         __u32 val;
 236
 237         switch (request) {
 238         case PTRACE_TRACEME:
 239         case PTRACE_ATTACH:
 240         case PTRACE_KILL:
 241         case PTRACE_CONT:
 242         case PTRACE_SINGLESTEP:
 243         case PTRACE_SINGLEBLOCK:
 244         case PTRACE_DETACH:
 245         case PTRACE_SYSCALL:
 246         case PTRACE_OLDSETOPTIONS:
 247         case PTRACE_SETOPTIONS:
 248         case PTRACE_SET_THREAD_AREA:
 249         case PTRACE_GET_THREAD_AREA:
 250                 return sys_ptrace(request, pid, addr, data);
 251
 252         default:
 253                 return -EINVAL;
 254
 255         case PTRACE_PEEKTEXT:
 256         case PTRACE_PEEKDATA:
 257         case PTRACE_POKEDATA:
 258         case PTRACE_POKETEXT:
 259         case PTRACE_POKEUSR:
 260         case PTRACE_PEEKUSR:
 261         case PTRACE_GETREGS:
 262         case PTRACE_SETREGS:
 263         case PTRACE_SETFPREGS:
 264         case PTRACE_GETFPREGS:
 265         case PTRACE_SETFPXREGS:
 266         case PTRACE_GETFPXREGS:
 267         case PTRACE_GETEVENTMSG:
 268                 break;
 269
 270         case PTRACE_SETSIGINFO:
 271         case PTRACE_GETSIGINFO:
 272                 return ptrace32_siginfo(request, pid, addr, data);
 273         }
 274
 275         child = ptrace_get_task_struct(pid);
 276         if (IS_ERR(child))
 277                 return PTR_ERR(child);
 278
 279         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 280         if (ret < 0)
 281                 goto out;
 282
 283         childregs = task_pt_regs(child);
 284
 285         switch (request) {
 286         case PTRACE_PEEKDATA:
 287         case PTRACE_PEEKTEXT:
 288                 ret = 0;
 289                 if (access_process_vm(child, addr, &val, sizeof(u32), 0) !=
 290                     sizeof(u32))
 291                         ret = -EIO;
 292                 else
 293                         ret = put_user(val, (unsigned int __user *)datap);
 294                 break;
 295
 296         case PTRACE_POKEDATA:
 297         case PTRACE_POKETEXT:
 298                 ret = 0;
 299                 if (access_process_vm(child, addr, &data, sizeof(u32), 1) !=
 300                     sizeof(u32))
 301                         ret = -EIO;
 302                 break;
 303
 304         case PTRACE_PEEKUSR:
 305                 ret = getreg32(child, addr, &val);
 306                 if (ret == 0)
 307                         ret = put_user(val, (__u32 __user *)datap);
 308                 break;
 309
 310         case PTRACE_POKEUSR:
 311                 ret = putreg32(child, addr, data);
 312                 break;
 313
 314         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 315                 int i;
 316
 317                 if (!access_ok(VERIFY_WRITE, datap, 16*4)) {
 318                         ret = -EIO;
 319                         break;
 320                 }
 321                 ret = 0;
 322                 for (i = 0; i <= 16*4; i += sizeof(__u32)) {
 323                         getreg32(child, i, &val);
 324                         ret |= __put_user(val, (u32 __user *)datap);
 325                         datap += sizeof(u32);
 326                 }
 327                 break;
 328         }
 329
 330         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 331                 unsigned long tmp;
 332                 int i;
 333
 334                 if (!access_ok(VERIFY_READ, datap, 16*4)) {
 335                         ret = -EIO;
 336                         break;
 337                 }
 338                 ret = 0;
 339                 for (i = 0; i <= 16*4; i += sizeof(u32)) {
 340                         ret |= __get_user(tmp, (u32 __user *)datap);
 341                         putreg32(child, i, tmp);
 342                         datap += sizeof(u32);
 343                 }
 344                 break;
 345         }
 346
 347         case PTRACE_GETFPREGS:
 348                 ret = -EIO;
 349                 if (!access_ok(VERIFY_READ, compat_ptr(data),
 350                                sizeof(struct user_i387_struct)))
 351                         break;
 352                 save_i387_ia32(child, datap, childregs, 1);
 353                 ret = 0;
 354                         break;
 355
 356         case PTRACE_SETFPREGS:
 357                 ret = -EIO;
 358                 if (!access_ok(VERIFY_WRITE, datap,
 359                                sizeof(struct user_i387_struct)))
 360                         break;
 361                 ret = 0;
 362                 /* don't check EFAULT to be bug-to-bug compatible to i386 */
 363                 restore_i387_ia32(child, datap, 1);
 364                 break;
 365
 366         case PTRACE_GETFPXREGS: {
 367                 struct user32_fxsr_struct __user *u = datap;
 368
 369                 init_fpu(child);
 370                 ret = -EIO;
 371                 if (!access_ok(VERIFY_WRITE, u, sizeof(*u)))
 372                         break;
 373                         ret = -EFAULT;
 374                 if (__copy_to_user(u, &child->thread.i387.fxsave, sizeof(*u)))
 375                         break;
 376                 ret = __put_user(childregs->cs, &u->fcs);
 377                 ret |= __put_user(child->thread.ds, &u->fos);
 378                 break;
 379         }
 380         case PTRACE_SETFPXREGS: {
 381                 struct user32_fxsr_struct __user *u = datap;
 382
 383                 unlazy_fpu(child);
 384                 ret = -EIO;
 385                 if (!access_ok(VERIFY_READ, u, sizeof(*u)))
 386                         break;
 387                 /*
 388                  * no checking to be bug-to-bug compatible with i386.
 389                  * but silence warning
 390                  */
 391                 if (__copy_from_user(&child->thread.i387.fxsave, u, sizeof(*u)))
 392                         ;
 393                 set_stopped_child_used_math(child);
 394                 child->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
 395                 ret = 0;
 396                 break;
 397         }
 398
 399         case PTRACE_GETEVENTMSG:
 400                 ret = put_user(child->ptrace_message,
 401                                (unsigned int __user *)compat_ptr(data));
 402                 break;
 403
 404         default:
 405                 BUG();
 406         }
 407
 408  out:
 409         put_task_struct(child);
 410         return ret;
 411 }