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/* |
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* paranoia.cpp - Check undocumented features of the Linux kernel that |
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* SheepShaver relies upon |
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* |
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* SheepShaver (C) 1997-2002 Christian Bauer and Marc Hellwig |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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|
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#include <unistd.h> |
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#include <stdio.h> |
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#include <signal.h> |
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#include <errno.h> |
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|
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#include "sysdeps.h" |
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#include "main.h" |
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#include "user_strings.h" |
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|
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typedef struct { |
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uint32 u[4]; |
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} __attribute((aligned(16))) vector128; |
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#include <linux/elf.h> |
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|
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#define DEBUG 1 |
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#include "debug.h" |
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|
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|
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// Constants |
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const uint32 SIG_STACK_SIZE = 0x10000; // Size of signal stack |
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|
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// Prototypes |
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extern "C" void *get_sp(void); |
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extern "C" void set_r2(uint32 val); |
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extern void paranoia_check(void); |
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static void sigusr2_handler(int sig, sigcontext_struct *sc); |
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|
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// Global variables |
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static void *sig_stack = NULL; |
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|
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static int err = 0; |
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static void *sig_sp = NULL; |
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static void *sig_r4 = NULL; |
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static int sig_sc_signal = 0; |
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static void *sig_sc_regs = NULL; |
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static uint32 sig_r2 = 0; |
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|
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|
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void paranoia_check(void) |
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{ |
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char str[256]; |
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|
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D(bug("Paranoia checks...\n")); |
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|
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// Create and install stack for signal handler |
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sig_stack = malloc(SIG_STACK_SIZE); |
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if (sig_stack == NULL) { |
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ErrorAlert(GetString(STR_NOT_ENOUGH_MEMORY_ERR)); |
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exit(1); |
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} |
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|
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struct sigaltstack old_stack; |
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struct sigaltstack new_stack; |
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new_stack.ss_sp = sig_stack; |
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new_stack.ss_flags = 0; |
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new_stack.ss_size = SIG_STACK_SIZE; |
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if (sigaltstack(&new_stack, &old_stack) < 0) { |
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sprintf(str, GetString(STR_SIGALTSTACK_ERR), strerror(errno)); |
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ErrorAlert(str); |
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exit(1); |
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} |
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|
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// Install SIGUSR2 signal handler |
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static struct sigaction old_action; |
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static struct sigaction sigusr2_action; |
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sigemptyset(&sigusr2_action.sa_mask); |
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sigusr2_action.sa_handler = (__sighandler_t)sigusr2_handler; |
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sigusr2_action.sa_flags = SA_ONSTACK | SA_RESTART; |
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sigusr2_action.sa_restorer = NULL; |
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if (sigaction(SIGUSR2, &sigusr2_action, &old_action) < 0) { |
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sprintf(str, GetString(STR_SIGUSR2_INSTALL_ERR), strerror(errno)); |
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ErrorAlert(str); |
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exit(1); |
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} |
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|
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// Raise SIGUSR2 |
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set_r2(0xaffebad5); |
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raise(SIGUSR2); |
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|
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// Check error code |
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switch (err) { |
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case 1: |
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printf("FATAL: sigaltstack() doesn't seem to work (sp in signal handler was %08lx, expected %08lx..%08lx)\n", (uint32)sig_sp, (uint32)sig_stack, (uint32)sig_stack + SIG_STACK_SIZE); |
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break; |
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case 2: |
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printf("FATAL: r4 in signal handler (%08lx) doesn't point to stack\n", (uint32)sig_r4); |
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break; |
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case 3: |
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printf("FATAL: r4 in signal handler doesn't seem to point to a sigcontext_struct (signal number was %d, expected %d)", sig_sc_signal, SIGUSR2); |
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break; |
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case 4: |
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printf("FATAL: sc->regs in signal handler (%08lx) doesn't point to stack\n", (uint32)sig_sc_regs); |
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break; |
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case 5: |
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printf("FATAL: sc->regs->gpr[2] in signal handler (%08lx) doesn't have expected value (%08x)\n", (uint32)sig_r2, 0xaffebad5); |
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break; |
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} |
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if (err) { |
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printf("Maybe you need a different kernel?\n"); |
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exit(1); |
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} |
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|
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// Clean up |
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D(bug("...passed\n")); |
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sigaction(SIGUSR2, &old_action, NULL); |
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sigaltstack(&old_stack, NULL); |
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free(sig_stack); |
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} |
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|
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|
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static void sigusr2_handler(int sig, sigcontext_struct *sc) |
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{ |
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// Check whether sigaltstack works |
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sig_sp = get_sp(); |
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if (sig_sp < sig_stack || sig_sp >= ((uint8 *)sig_stack + SIG_STACK_SIZE)) { |
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err = 1; |
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return; |
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} |
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|
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// Check whether r4 points to info on the stack |
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sig_r4 = sc; |
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if (sig_r4 < sig_stack || sig_r4 >= ((uint8 *)sig_stack + SIG_STACK_SIZE)) { |
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err = 2; |
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return; |
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} |
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|
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// Check whether r4 looks like a sigcontext |
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sig_sc_signal = sc->signal; |
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if (sig_sc_signal != SIGUSR2) { |
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err = 3; |
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return; |
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} |
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|
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// Check whether sc->regs points to info on the stack |
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sig_sc_regs = sc->regs; |
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if (sig_sc_regs < sig_stack || sig_sc_regs >= ((uint8 *)sig_stack + SIG_STACK_SIZE)) { |
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err = 4; |
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return; |
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} |
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|
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// Check whether r2 still holds the value we set it to |
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sig_r2 = sc->regs->gpr[2]; |
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if (sig_r2 != 0xaffebad5) { |
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err = 5; |
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return; |
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} |
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} |
