1 /* 2 * Copyright (C) 2000 Jeff Dike (jdike@karaya.com) 3 * Licensed under the GPL 4 */ 5 6 #include "linux/sched.h" 7 #include "linux/mm.h" 8 #include "linux/errno.h" 9 #include "linux/smp_lock.h" 10 #include "linux/security.h" 11 #include "linux/ptrace.h" 12 #include "linux/audit.h" 13 #ifdef CONFIG_PROC_MM 14 #include "linux/proc_mm.h" 15 #endif 16 #include "asm/ptrace.h" 17 #include "asm/uaccess.h" 18 #include "kern_util.h" 19 #include "skas_ptrace.h" 20 #include "sysdep/ptrace.h" 21 22 /* 23 * Called by kernel/ptrace.c when detaching.. 24 */ 25 void ptrace_disable(struct task_struct *child) 26 { 27 child->ptrace &= ~PT_DTRACE; 28 child->thread.singlestep_syscall = 0; 29 } 30 31 long sys_ptrace(long request, long pid, long addr, long data) 32 { 33 struct task_struct *child; 34 int i, ret; 35 36 lock_kernel(); 37 ret = -EPERM; 38 if (request == PTRACE_TRACEME) { 39 /* are we already being traced? */ 40 if (current->ptrace & PT_PTRACED) 41 goto out; 42 43 ret = security_ptrace(current->parent, current); 44 if (ret) 45 goto out; 46 47 /* set the ptrace bit in the process flags. */ 48 current->ptrace |= PT_PTRACED; 49 ret = 0; 50 goto out; 51 } 52 ret = -ESRCH; 53 read_lock(&tasklist_lock); 54 child = find_task_by_pid(pid); 55 if (child) 56 get_task_struct(child); 57 read_unlock(&tasklist_lock); 58 if (!child) 59 goto out; 60 61 ret = -EPERM; 62 if (pid == 1) /* you may not mess with init */ 63 goto out_tsk; 64 65 if (request == PTRACE_ATTACH) { 66 ret = ptrace_attach(child); 67 goto out_tsk; 68 } 69 70 ret = ptrace_check_attach(child, request == PTRACE_KILL); 71 if (ret < 0) 72 goto out_tsk; 73 74 switch (request) { 75 /* when I and D space are separate, these will need to be fixed. */ 76 case PTRACE_PEEKTEXT: /* read word at location addr. */ 77 case PTRACE_PEEKDATA: { 78 unsigned long tmp; 79 int copied; 80 81 ret = -EIO; 82 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); 83 if (copied != sizeof(tmp)) 84 break; 85 ret = put_user(tmp, (unsigned long __user *) data); 86 break; 87 } 88 89 /* read the word at location addr in the USER area. */ 90 case PTRACE_PEEKUSR: { 91 unsigned long tmp; 92 93 ret = -EIO; 94 if ((addr & 3) || addr < 0) 95 break; 96 97 tmp = 0; /* Default return condition */ 98 if(addr < MAX_REG_OFFSET){ 99 tmp = getreg(child, addr); 100 } 101 else if((addr >= offsetof(struct user, u_debugreg[0])) && 102 (addr <= offsetof(struct user, u_debugreg[7]))){ 103 addr -= offsetof(struct user, u_debugreg[0]); 104 addr = addr >> 2; 105 tmp = child->thread.arch.debugregs[addr]; 106 } 107 ret = put_user(tmp, (unsigned long __user *) data); 108 break; 109 } 110 111 /* when I and D space are separate, this will have to be fixed. */ 112 case PTRACE_POKETEXT: /* write the word at location addr. */ 113 case PTRACE_POKEDATA: 114 ret = -EIO; 115 if (access_process_vm(child, addr, &data, sizeof(data), 116 1) != sizeof(data)) 117 break; 118 ret = 0; 119 break; 120 121 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ 122 ret = -EIO; 123 if ((addr & 3) || addr < 0) 124 break; 125 126 if (addr < MAX_REG_OFFSET) { 127 ret = putreg(child, addr, data); 128 break; 129 } 130 #if 0 /* XXX x86_64 */ 131 else if((addr >= offsetof(struct user, u_debugreg[0])) && 132 (addr <= offsetof(struct user, u_debugreg[7]))){ 133 addr -= offsetof(struct user, u_debugreg[0]); 134 addr = addr >> 2; 135 if((addr == 4) || (addr == 5)) break; 136 child->thread.arch.debugregs[addr] = data; 137 ret = 0; 138 } 139 #endif 140 141 break; 142 143 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ 144 case PTRACE_CONT: { /* restart after signal. */ 145 ret = -EIO; 146 if ((unsigned long) data > _NSIG) 147 break; 148 149 child->ptrace &= ~PT_DTRACE; 150 child->thread.singlestep_syscall = 0; 151 if (request == PTRACE_SYSCALL) { 152 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 153 } 154 else { 155 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 156 } 157 child->exit_code = data; 158 wake_up_process(child); 159 ret = 0; 160 break; 161 } 162 163 /* 164 * make the child exit. Best I can do is send it a sigkill. 165 * perhaps it should be put in the status that it wants to 166 * exit. 167 */ 168 case PTRACE_KILL: { 169 ret = 0; 170 if (child->exit_state == EXIT_ZOMBIE) /* already dead */ 171 break; 172 173 child->ptrace &= ~PT_DTRACE; 174 child->thread.singlestep_syscall = 0; 175 child->exit_code = SIGKILL; 176 wake_up_process(child); 177 break; 178 } 179 180 case PTRACE_SINGLESTEP: { /* set the trap flag. */ 181 ret = -EIO; 182 if ((unsigned long) data > _NSIG) 183 break; 184 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 185 child->ptrace |= PT_DTRACE; 186 child->thread.singlestep_syscall = 0; 187 child->exit_code = data; 188 /* give it a chance to run. */ 189 wake_up_process(child); 190 ret = 0; 191 break; 192 } 193 194 case PTRACE_DETACH: 195 /* detach a process that was attached. */ 196 ret = ptrace_detach(child, data); 197 break; 198 199 #ifdef PTRACE_GETREGS 200 case PTRACE_GETREGS: { /* Get all gp regs from the child. */ 201 if (!access_ok(VERIFY_WRITE, (unsigned long *)data, 202 MAX_REG_OFFSET)) { 203 ret = -EIO; 204 break; 205 } 206 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) { 207 __put_user(getreg(child, i), 208 (unsigned long __user *) data); 209 data += sizeof(long); 210 } 211 ret = 0; 212 break; 213 } 214 #endif 215 #ifdef PTRACE_SETREGS 216 case PTRACE_SETREGS: { /* Set all gp regs in the child. */ 217 unsigned long tmp = 0; 218 if (!access_ok(VERIFY_READ, (unsigned *)data, 219 MAX_REG_OFFSET)) { 220 ret = -EIO; 221 break; 222 } 223 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) { 224 __get_user(tmp, (unsigned long __user *) data); 225 putreg(child, i, tmp); 226 data += sizeof(long); 227 } 228 ret = 0; 229 break; 230 } 231 #endif 232 #ifdef PTRACE_GETFPREGS 233 case PTRACE_GETFPREGS: /* Get the child FPU state. */ 234 ret = get_fpregs(data, child); 235 break; 236 #endif 237 #ifdef PTRACE_SETFPREGS 238 case PTRACE_SETFPREGS: /* Set the child FPU state. */ 239 ret = set_fpregs(data, child); 240 break; 241 #endif 242 #ifdef PTRACE_GETFPXREGS 243 case PTRACE_GETFPXREGS: /* Get the child FPU state. */ 244 ret = get_fpxregs(data, child); 245 break; 246 #endif 247 #ifdef PTRACE_SETFPXREGS 248 case PTRACE_SETFPXREGS: /* Set the child FPU state. */ 249 ret = set_fpxregs(data, child); 250 break; 251 #endif 252 case PTRACE_FAULTINFO: { 253 struct ptrace_faultinfo fault; 254 255 fault = ((struct ptrace_faultinfo) 256 { .is_write = child->thread.err, 257 .addr = child->thread.cr2 }); 258 ret = copy_to_user((unsigned long __user *) data, &fault, 259 sizeof(fault)); 260 if(ret) 261 break; 262 break; 263 } 264 case PTRACE_SIGPENDING: 265 ret = copy_to_user((unsigned long __user *) data, 266 &child->pending.signal, 267 sizeof(child->pending.signal)); 268 break; 269 270 case PTRACE_LDT: { 271 struct ptrace_ldt ldt; 272 273 if(copy_from_user(&ldt, (unsigned long __user *) data, 274 sizeof(ldt))){ 275 ret = -EIO; 276 break; 277 } 278 279 /* This one is confusing, so just punt and return -EIO for 280 * now 281 */ 282 ret = -EIO; 283 break; 284 } 285 #ifdef CONFIG_PROC_MM 286 case PTRACE_SWITCH_MM: { 287 struct mm_struct *old = child->mm; 288 struct mm_struct *new = proc_mm_get_mm(data); 289 290 if(IS_ERR(new)){ 291 ret = PTR_ERR(new); 292 break; 293 } 294 295 atomic_inc(&new->mm_users); 296 child->mm = new; 297 child->active_mm = new; 298 mmput(old); 299 ret = 0; 300 break; 301 } 302 #endif 303 default: 304 ret = ptrace_request(child, request, addr, data); 305 break; 306 } 307 out_tsk: 308 put_task_struct(child); 309 out: 310 unlock_kernel(); 311 return ret; 312 } 313 314 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs, 315 int error_code) 316 { 317 struct siginfo info; 318 319 memset(&info, 0, sizeof(info)); 320 info.si_signo = SIGTRAP; 321 info.si_code = TRAP_BRKPT; 322 323 /* User-mode eip? */ 324 info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL; 325 326 /* Send us the fakey SIGTRAP */ 327 force_sig_info(SIGTRAP, &info, tsk); 328 } 329 330 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and 331 * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check 332 */ 333 void syscall_trace(union uml_pt_regs *regs, int entryexit) 334 { 335 int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit; 336 int tracesysgood; 337 338 if (unlikely(current->audit_context)) { 339 if (!entryexit) 340 audit_syscall_entry(current, 341 UPT_SYSCALL_NR(®s->regs), 342 UPT_SYSCALL_ARG1(®s->regs), 343 UPT_SYSCALL_ARG2(®s->regs), 344 UPT_SYSCALL_ARG3(®s->regs), 345 UPT_SYSCALL_ARG4(®s->regs)); 346 else 347 audit_syscall_exit(current, 348 UPT_SYSCALL_RET(®s->regs)); 349 } 350 351 /* Fake a debug trap */ 352 if (is_singlestep) 353 send_sigtrap(current, regs, 0); 354 355 if (!test_thread_flag(TIF_SYSCALL_TRACE)) 356 return; 357 358 if (!(current->ptrace & PT_PTRACED)) 359 return; 360 361 /* the 0x80 provides a way for the tracing parent to distinguish 362 between a syscall stop and SIGTRAP delivery */ 363 tracesysgood = (current->ptrace & PT_TRACESYSGOOD); 364 ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0)); 365 366 if (entryexit) /* force do_signal() --> is_syscall() */ 367 set_thread_flag(TIF_SIGPENDING); 368 369 /* this isn't the same as continuing with a signal, but it will do 370 * for normal use. strace only continues with a signal if the 371 * stopping signal is not SIGTRAP. -brl 372 */ 373 if (current->exit_code) { 374 send_sig(current->exit_code, current, 1); 375 current->exit_code = 0; 376 } 377 } 378 379 /* 380 * Overrides for Emacs so that we follow Linus's tabbing style. 381 * Emacs will notice this stuff at the end of the file and automatically 382 * adjust the settings for this buffer only. This must remain at the end 383 * of the file. 384 * --------------------------------------------------------------------------- 385 * Local variables: 386 * c-file-style: "linux" 387 * End: 388 */ 389