Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 1 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com) |
| 3 | * Licensed under the GPL |
| 4 | */ |
| 5 | |
| 6 | #include <stdio.h> |
| 7 | #include <unistd.h> |
| 8 | #include <signal.h> |
| 9 | #include <sched.h> |
| 10 | #include <errno.h> |
| 11 | #include <stdarg.h> |
| 12 | #include <stdlib.h> |
| 13 | #include <setjmp.h> |
| 14 | #include <sys/time.h> |
| 15 | #include <sys/wait.h> |
| 16 | #include <sys/mman.h> |
| 17 | #include <asm/unistd.h> |
| 18 | #include <asm/page.h> |
| 19 | #include "user_util.h" |
| 20 | #include "kern_util.h" |
| 21 | #include "user.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | #include "signal_kern.h" |
| 23 | #include "signal_user.h" |
| 24 | #include "sysdep/ptrace.h" |
| 25 | #include "sysdep/sigcontext.h" |
| 26 | #include "irq_user.h" |
| 27 | #include "ptrace_user.h" |
| 28 | #include "time_user.h" |
| 29 | #include "init.h" |
| 30 | #include "os.h" |
| 31 | #include "uml-config.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | #include "choose-mode.h" |
| 33 | #include "mode.h" |
Jeff Dike | d67b569 | 2005-07-07 17:56:49 -0700 | [diff] [blame] | 34 | #include "tempfile.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #ifdef UML_CONFIG_MODE_SKAS |
| 36 | #include "skas.h" |
| 37 | #include "skas_ptrace.h" |
| 38 | #include "registers.h" |
| 39 | #endif |
| 40 | |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 41 | static int ptrace_child(void *arg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | { |
| 43 | int ret; |
| 44 | int pid = os_getpid(), ppid = getppid(); |
| 45 | int sc_result; |
| 46 | |
| 47 | if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){ |
| 48 | perror("ptrace"); |
| 49 | os_kill_process(pid, 0); |
| 50 | } |
| 51 | os_stop_process(pid); |
| 52 | |
| 53 | /*This syscall will be intercepted by the parent. Don't call more than |
| 54 | * once, please.*/ |
| 55 | sc_result = os_getpid(); |
| 56 | |
| 57 | if (sc_result == pid) |
| 58 | ret = 1; /*Nothing modified by the parent, we are running |
| 59 | normally.*/ |
| 60 | else if (sc_result == ppid) |
| 61 | ret = 0; /*Expected in check_ptrace and check_sysemu when they |
| 62 | succeed in modifying the stack frame*/ |
| 63 | else |
| 64 | ret = 2; /*Serious trouble! This could be caused by a bug in |
| 65 | host 2.6 SKAS3/2.6 patch before release -V6, together |
| 66 | with a bug in the UML code itself.*/ |
| 67 | _exit(ret); |
| 68 | } |
| 69 | |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 70 | static int start_ptraced_child(void **stack_out) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | { |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 72 | void *stack; |
| 73 | unsigned long sp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | int pid, n, status; |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 75 | |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 76 | stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, |
| 77 | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
| 78 | if(stack == MAP_FAILED) |
| 79 | panic("check_ptrace : mmap failed, errno = %d", errno); |
| 80 | sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *); |
| 81 | pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | if(pid < 0) |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 83 | panic("start_ptraced_child : clone failed, errno = %d", errno); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); |
| 85 | if(n < 0) |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 86 | panic("check_ptrace : clone failed, errno = %d", errno); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) |
| 88 | panic("check_ptrace : expected SIGSTOP, got status = %d", |
| 89 | status); |
| 90 | |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 91 | *stack_out = stack; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | return(pid); |
| 93 | } |
| 94 | |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 95 | /* When testing for SYSEMU support, if it is one of the broken versions, we |
| 96 | * must just avoid using sysemu, not panic, but only if SYSEMU features are |
| 97 | * broken. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | * So only for SYSEMU features we test mustpanic, while normal host features |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 99 | * must work anyway! |
| 100 | */ |
| 101 | static int stop_ptraced_child(int pid, void *stack, int exitcode, |
| 102 | int mustpanic) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | { |
| 104 | int status, n, ret = 0; |
| 105 | |
| 106 | if(ptrace(PTRACE_CONT, pid, 0, 0) < 0) |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 107 | panic("check_ptrace : ptrace failed, errno = %d", errno); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | CATCH_EINTR(n = waitpid(pid, &status, 0)); |
| 109 | if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) { |
| 110 | int exit_with = WEXITSTATUS(status); |
| 111 | if (exit_with == 2) |
| 112 | printk("check_ptrace : child exited with status 2. " |
| 113 | "Serious trouble happening! Try updating your " |
| 114 | "host skas patch!\nDisabling SYSEMU support."); |
| 115 | printk("check_ptrace : child exited with exitcode %d, while " |
| 116 | "expecting %d; status 0x%x", exit_with, |
| 117 | exitcode, status); |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 118 | if (mustpanic) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 119 | panic("\n"); |
| 120 | else |
| 121 | printk("\n"); |
| 122 | ret = -1; |
| 123 | } |
| 124 | |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 125 | if(munmap(stack, PAGE_SIZE) < 0) |
| 126 | panic("check_ptrace : munmap failed, errno = %d", errno); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 127 | return ret; |
| 128 | } |
| 129 | |
Paolo 'Blaisorblade' Giarrusso | cb66504 | 2005-07-27 11:43:31 -0700 | [diff] [blame] | 130 | int ptrace_faultinfo = 1; |
| 131 | int proc_mm = 1; |
| 132 | |
| 133 | static int __init skas0_cmd_param(char *str, int* add) |
| 134 | { |
| 135 | ptrace_faultinfo = proc_mm = 0; |
| 136 | return 0; |
| 137 | } |
| 138 | |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 139 | __uml_setup("skas0", skas0_cmd_param, |
| 140 | "skas0\n" |
| 141 | " Disables SKAS3 usage, so that SKAS0 is used, unless \n" |
| 142 | " you specify mode=tt.\n\n"); |
| 143 | |
| 144 | static int force_sysemu_disabled = 0; |
| 145 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | static int __init nosysemu_cmd_param(char *str, int* add) |
| 147 | { |
| 148 | force_sysemu_disabled = 1; |
| 149 | return 0; |
| 150 | } |
| 151 | |
| 152 | __uml_setup("nosysemu", nosysemu_cmd_param, |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 153 | "nosysemu\n" |
| 154 | " Turns off syscall emulation patch for ptrace (SYSEMU) on.\n" |
| 155 | " SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n" |
| 156 | " behaviour of ptrace() and helps reducing host context switch rate.\n" |
| 157 | " To make it working, you need a kernel patch for your host, too.\n" |
| 158 | " See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n" |
| 159 | " information.\n\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | |
| 161 | static void __init check_sysemu(void) |
| 162 | { |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 163 | void *stack; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 164 | int pid, syscall, n, status, count=0; |
| 165 | |
| 166 | printk("Checking syscall emulation patch for ptrace..."); |
| 167 | sysemu_supported = 0; |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 168 | pid = start_ptraced_child(&stack); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | |
| 170 | if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0) |
| 171 | goto fail; |
| 172 | |
| 173 | CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); |
| 174 | if (n < 0) |
| 175 | panic("check_sysemu : wait failed, errno = %d", errno); |
| 176 | if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP)) |
| 177 | panic("check_sysemu : expected SIGTRAP, " |
| 178 | "got status = %d", status); |
| 179 | |
| 180 | n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET, |
| 181 | os_getpid()); |
| 182 | if(n < 0) |
| 183 | panic("check_sysemu : failed to modify system " |
| 184 | "call return, errno = %d", errno); |
| 185 | |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 186 | if (stop_ptraced_child(pid, stack, 0, 0) < 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | goto fail_stopped; |
| 188 | |
| 189 | sysemu_supported = 1; |
| 190 | printk("OK\n"); |
| 191 | set_using_sysemu(!force_sysemu_disabled); |
| 192 | |
| 193 | printk("Checking advanced syscall emulation patch for ptrace..."); |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 194 | pid = start_ptraced_child(&stack); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | while(1){ |
| 196 | count++; |
| 197 | if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0) |
| 198 | goto fail; |
| 199 | CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); |
| 200 | if(n < 0) |
| 201 | panic("check_ptrace : wait failed, errno = %d", errno); |
| 202 | if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP)) |
| 203 | panic("check_ptrace : expected (SIGTRAP|SYSCALL_TRAP), " |
| 204 | "got status = %d", status); |
| 205 | |
| 206 | syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET, |
| 207 | 0); |
| 208 | if(syscall == __NR_getpid){ |
| 209 | if (!count) |
| 210 | panic("check_ptrace : SYSEMU_SINGLESTEP doesn't singlestep"); |
| 211 | n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET, |
| 212 | os_getpid()); |
| 213 | if(n < 0) |
| 214 | panic("check_sysemu : failed to modify system " |
| 215 | "call return, errno = %d", errno); |
| 216 | break; |
| 217 | } |
| 218 | } |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 219 | if (stop_ptraced_child(pid, stack, 0, 0) < 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | goto fail_stopped; |
| 221 | |
| 222 | sysemu_supported = 2; |
| 223 | printk("OK\n"); |
| 224 | |
| 225 | if ( !force_sysemu_disabled ) |
| 226 | set_using_sysemu(sysemu_supported); |
| 227 | return; |
| 228 | |
| 229 | fail: |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 230 | stop_ptraced_child(pid, stack, 1, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | fail_stopped: |
| 232 | printk("missing\n"); |
| 233 | } |
| 234 | |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 235 | static void __init check_ptrace(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | { |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 237 | void *stack; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | int pid, syscall, n, status; |
| 239 | |
| 240 | printk("Checking that ptrace can change system call numbers..."); |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 241 | pid = start_ptraced_child(&stack); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 243 | if(ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0) |
| 244 | panic("check_ptrace: PTRACE_OLDSETOPTIONS failed, errno = %d", errno); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | |
| 246 | while(1){ |
| 247 | if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0) |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 248 | panic("check_ptrace : ptrace failed, errno = %d", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | errno); |
| 250 | CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); |
| 251 | if(n < 0) |
| 252 | panic("check_ptrace : wait failed, errno = %d", errno); |
| 253 | if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP + 0x80)) |
| 254 | panic("check_ptrace : expected SIGTRAP + 0x80, " |
| 255 | "got status = %d", status); |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 256 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET, |
| 258 | 0); |
| 259 | if(syscall == __NR_getpid){ |
| 260 | n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, |
| 261 | __NR_getppid); |
| 262 | if(n < 0) |
| 263 | panic("check_ptrace : failed to modify system " |
| 264 | "call, errno = %d", errno); |
| 265 | break; |
| 266 | } |
| 267 | } |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 268 | stop_ptraced_child(pid, stack, 0, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | printk("OK\n"); |
| 270 | check_sysemu(); |
| 271 | } |
| 272 | |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 273 | void os_early_checks(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | { |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 275 | check_ptrace(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | } |
| 277 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | #ifdef UML_CONFIG_MODE_SKAS |
Jeff Dike | d67b569 | 2005-07-07 17:56:49 -0700 | [diff] [blame] | 279 | static inline void check_skas3_ptrace_support(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | { |
| 281 | struct ptrace_faultinfo fi; |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 282 | void *stack; |
Jeff Dike | d67b569 | 2005-07-07 17:56:49 -0700 | [diff] [blame] | 283 | int pid, n; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | |
| 285 | printf("Checking for the skas3 patch in the host..."); |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 286 | pid = start_ptraced_child(&stack); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | |
| 288 | n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi); |
| 289 | if (n < 0) { |
Paolo 'Blaisorblade' Giarrusso | cb66504 | 2005-07-27 11:43:31 -0700 | [diff] [blame] | 290 | ptrace_faultinfo = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 291 | if(errno == EIO) |
| 292 | printf("not found\n"); |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 293 | else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 294 | perror("not found"); |
Jeff Dike | d67b569 | 2005-07-07 17:56:49 -0700 | [diff] [blame] | 295 | } |
| 296 | else { |
Paolo 'Blaisorblade' Giarrusso | cb66504 | 2005-07-27 11:43:31 -0700 | [diff] [blame] | 297 | if (!ptrace_faultinfo) |
| 298 | printf("found but disabled on command line\n"); |
| 299 | else |
| 300 | printf("found\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 301 | } |
| 302 | |
| 303 | init_registers(pid); |
Jeff Dike | b85e968 | 2005-07-28 21:16:01 -0700 | [diff] [blame] | 304 | stop_ptraced_child(pid, stack, 1, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | } |
| 306 | |
| 307 | int can_do_skas(void) |
| 308 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 309 | printf("Checking for /proc/mm..."); |
| 310 | if (os_access("/proc/mm", OS_ACC_W_OK) < 0) { |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 311 | proc_mm = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 312 | printf("not found\n"); |
Gennady Sharapov | 60d339f | 2005-09-03 15:57:47 -0700 | [diff] [blame^] | 313 | } |
| 314 | else { |
Paolo 'Blaisorblade' Giarrusso | cb66504 | 2005-07-27 11:43:31 -0700 | [diff] [blame] | 315 | if (!proc_mm) |
| 316 | printf("found but disabled on command line\n"); |
| 317 | else |
| 318 | printf("found\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | } |
| 320 | |
Jeff Dike | d67b569 | 2005-07-07 17:56:49 -0700 | [diff] [blame] | 321 | check_skas3_ptrace_support(); |
| 322 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | } |
| 324 | #else |
| 325 | int can_do_skas(void) |
| 326 | { |
| 327 | return(0); |
| 328 | } |
| 329 | #endif |