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 static inline void set_singlestepping(struct task_struct *child, int on) 23 { 24 if (on) 25 child->ptrace |= PT_DTRACE; 26 else 27 child->ptrace &= ~PT_DTRACE; 28 child->thread.singlestep_syscall = 0; 29 30 #ifdef SUBARCH_SET_SINGLESTEPPING 31 SUBARCH_SET_SINGLESTEPPING(child, on); 32 #endif 33 } 34 35 /* 36 * Called by kernel/ptrace.c when detaching.. 37 */ 38 void ptrace_disable(struct task_struct *child) 39 { 40 set_singlestepping(child,0); 41 } 42 43 extern int peek_user(struct task_struct * child, long addr, long data); 44 extern int poke_user(struct task_struct * child, long addr, long data); 45 46 long sys_ptrace(long request, long pid, long addr, long data) 47 { 48 struct task_struct *child; 49 int i, ret; 50 51 lock_kernel(); 52 ret = -EPERM; 53 if (request == PTRACE_TRACEME) { 54 /* are we already being traced? */ 55 if (current->ptrace & PT_PTRACED) 56 goto out; 57 58 ret = security_ptrace(current->parent, current); 59 if (ret) 60 goto out; 61 62 /* set the ptrace bit in the process flags. */ 63 current->ptrace |= PT_PTRACED; 64 ret = 0; 65 goto out; 66 } 67 ret = -ESRCH; 68 read_lock(&tasklist_lock); 69 child = find_task_by_pid(pid); 70 if (child) 71 get_task_struct(child); 72 read_unlock(&tasklist_lock); 73 if (!child) 74 goto out; 75 76 ret = -EPERM; 77 if (pid == 1) /* you may not mess with init */ 78 goto out_tsk; 79 80 if (request == PTRACE_ATTACH) { 81 ret = ptrace_attach(child); 82 goto out_tsk; 83 } 84 85 #ifdef SUBACH_PTRACE_SPECIAL 86 SUBARCH_PTRACE_SPECIAL(child,request,addr,data); 87 #endif 88 89 ret = ptrace_check_attach(child, request == PTRACE_KILL); 90 if (ret < 0) 91 goto out_tsk; 92 93 switch (request) { 94 /* when I and D space are separate, these will need to be fixed. */ 95 case PTRACE_PEEKTEXT: /* read word at location addr. */ 96 case PTRACE_PEEKDATA: { 97 unsigned long tmp; 98 int copied; 99 100 ret = -EIO; 101 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); 102 if (copied != sizeof(tmp)) 103 break; 104 ret = put_user(tmp, (unsigned long __user *) data); 105 break; 106 } 107 108 /* read the word at location addr in the USER area. */ 109 case PTRACE_PEEKUSR: 110 ret = peek_user(child, addr, data); 111 break; 112 113 /* when I and D space are separate, this will have to be fixed. */ 114 case PTRACE_POKETEXT: /* write the word at location addr. */ 115 case PTRACE_POKEDATA: 116 ret = -EIO; 117 if (access_process_vm(child, addr, &data, sizeof(data), 118 1) != sizeof(data)) 119 break; 120 ret = 0; 121 break; 122 123 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ 124 ret = poke_user(child, addr, data); 125 break; 126 127 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ 128 case PTRACE_CONT: { /* restart after signal. */ 129 ret = -EIO; 130 if (!valid_signal(data)) 131 break; 132 133 set_singlestepping(child, 0); 134 if (request == PTRACE_SYSCALL) { 135 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 136 } 137 else { 138 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 139 } 140 child->exit_code = data; 141 wake_up_process(child); 142 ret = 0; 143 break; 144 } 145 146 /* 147 * make the child exit. Best I can do is send it a sigkill. 148 * perhaps it should be put in the status that it wants to 149 * exit. 150 */ 151 case PTRACE_KILL: { 152 ret = 0; 153 if (child->exit_state == EXIT_ZOMBIE) /* already dead */ 154 break; 155 156 set_singlestepping(child, 0); 157 child->exit_code = SIGKILL; 158 wake_up_process(child); 159 break; 160 } 161 162 case PTRACE_SINGLESTEP: { /* set the trap flag. */ 163 ret = -EIO; 164 if (!valid_signal(data)) 165 break; 166 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 167 set_singlestepping(child, 1); 168 child->exit_code = data; 169 /* give it a chance to run. */ 170 wake_up_process(child); 171 ret = 0; 172 break; 173 } 174 175 case PTRACE_DETACH: 176 /* detach a process that was attached. */ 177 ret = ptrace_detach(child, data); 178 break; 179 180 #ifdef PTRACE_GETREGS 181 case PTRACE_GETREGS: { /* Get all gp regs from the child. */ 182 if (!access_ok(VERIFY_WRITE, (unsigned long *)data, 183 MAX_REG_OFFSET)) { 184 ret = -EIO; 185 break; 186 } 187 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) { 188 __put_user(getreg(child, i), 189 (unsigned long __user *) data); 190 data += sizeof(long); 191 } 192 ret = 0; 193 break; 194 } 195 #endif 196 #ifdef PTRACE_SETREGS 197 case PTRACE_SETREGS: { /* Set all gp regs in the child. */ 198 unsigned long tmp = 0; 199 if (!access_ok(VERIFY_READ, (unsigned *)data, 200 MAX_REG_OFFSET)) { 201 ret = -EIO; 202 break; 203 } 204 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) { 205 __get_user(tmp, (unsigned long __user *) data); 206 putreg(child, i, tmp); 207 data += sizeof(long); 208 } 209 ret = 0; 210 break; 211 } 212 #endif 213 #ifdef PTRACE_GETFPREGS 214 case PTRACE_GETFPREGS: /* Get the child FPU state. */ 215 ret = get_fpregs(data, child); 216 break; 217 #endif 218 #ifdef PTRACE_SETFPREGS 219 case PTRACE_SETFPREGS: /* Set the child FPU state. */ 220 ret = set_fpregs(data, child); 221 break; 222 #endif 223 #ifdef PTRACE_GETFPXREGS 224 case PTRACE_GETFPXREGS: /* Get the child FPU state. */ 225 ret = get_fpxregs(data, child); 226 break; 227 #endif 228 #ifdef PTRACE_SETFPXREGS 229 case PTRACE_SETFPXREGS: /* Set the child FPU state. */ 230 ret = set_fpxregs(data, child); 231 break; 232 #endif 233 case PTRACE_FAULTINFO: { 234 /* Take the info from thread->arch->faultinfo, 235 * but transfer max. sizeof(struct ptrace_faultinfo). 236 * On i386, ptrace_faultinfo is smaller! 237 */ 238 ret = copy_to_user((unsigned long __user *) data, 239 &child->thread.arch.faultinfo, 240 sizeof(struct ptrace_faultinfo)); 241 if(ret) 242 break; 243 break; 244 } 245 246 #ifdef PTRACE_LDT 247 case PTRACE_LDT: { 248 struct ptrace_ldt ldt; 249 250 if(copy_from_user(&ldt, (unsigned long __user *) data, 251 sizeof(ldt))){ 252 ret = -EIO; 253 break; 254 } 255 256 /* This one is confusing, so just punt and return -EIO for 257 * now 258 */ 259 ret = -EIO; 260 break; 261 } 262 #endif 263 #ifdef CONFIG_PROC_MM 264 case PTRACE_SWITCH_MM: { 265 struct mm_struct *old = child->mm; 266 struct mm_struct *new = proc_mm_get_mm(data); 267 268 if(IS_ERR(new)){ 269 ret = PTR_ERR(new); 270 break; 271 } 272 273 atomic_inc(&new->mm_users); 274 child->mm = new; 275 child->active_mm = new; 276 mmput(old); 277 ret = 0; 278 break; 279 } 280 #endif 281 default: 282 ret = ptrace_request(child, request, addr, data); 283 break; 284 } 285 out_tsk: 286 put_task_struct(child); 287 out: 288 unlock_kernel(); 289 return ret; 290 } 291 292 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs, 293 int error_code) 294 { 295 struct siginfo info; 296 297 memset(&info, 0, sizeof(info)); 298 info.si_signo = SIGTRAP; 299 info.si_code = TRAP_BRKPT; 300 301 /* User-mode eip? */ 302 info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL; 303 304 /* Send us the fakey SIGTRAP */ 305 force_sig_info(SIGTRAP, &info, tsk); 306 } 307 308 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and 309 * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check 310 */ 311 void syscall_trace(union uml_pt_regs *regs, int entryexit) 312 { 313 int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit; 314 int tracesysgood; 315 316 if (unlikely(current->audit_context)) { 317 if (!entryexit) 318 audit_syscall_entry(current, 319 HOST_AUDIT_ARCH, 320 UPT_SYSCALL_NR(regs), 321 UPT_SYSCALL_ARG1(regs), 322 UPT_SYSCALL_ARG2(regs), 323 UPT_SYSCALL_ARG3(regs), 324 UPT_SYSCALL_ARG4(regs)); 325 else audit_syscall_exit(current, 326 AUDITSC_RESULT(UPT_SYSCALL_RET(regs)), 327 UPT_SYSCALL_RET(regs)); 328 } 329 330 /* Fake a debug trap */ 331 if (is_singlestep) 332 send_sigtrap(current, regs, 0); 333 334 if (!test_thread_flag(TIF_SYSCALL_TRACE)) 335 return; 336 337 if (!(current->ptrace & PT_PTRACED)) 338 return; 339 340 /* the 0x80 provides a way for the tracing parent to distinguish 341 between a syscall stop and SIGTRAP delivery */ 342 tracesysgood = (current->ptrace & PT_TRACESYSGOOD); 343 ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0)); 344 345 if (entryexit) /* force do_signal() --> is_syscall() */ 346 set_thread_flag(TIF_SIGPENDING); 347 348 /* this isn't the same as continuing with a signal, but it will do 349 * for normal use. strace only continues with a signal if the 350 * stopping signal is not SIGTRAP. -brl 351 */ 352 if (current->exit_code) { 353 send_sig(current->exit_code, current, 1); 354 current->exit_code = 0; 355 } 356 } 357