| /* |
| * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com) |
| * Licensed under the GPL |
| */ |
| |
| #include <pty.h> |
| #include <stdio.h> |
| #include <stddef.h> |
| #include <stdarg.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <signal.h> |
| #include <sched.h> |
| #include <fcntl.h> |
| #include <errno.h> |
| #include <setjmp.h> |
| #include <sys/time.h> |
| #include <sys/wait.h> |
| #include <sys/mman.h> |
| #include <asm/unistd.h> |
| #include <asm/page.h> |
| #include <sys/types.h> |
| #include "user_util.h" |
| #include "kern_util.h" |
| #include "user.h" |
| #include "signal_kern.h" |
| #include "sysdep/ptrace.h" |
| #include "sysdep/sigcontext.h" |
| #include "irq_user.h" |
| #include "ptrace_user.h" |
| #include "mem_user.h" |
| #include "init.h" |
| #include "os.h" |
| #include "uml-config.h" |
| #include "choose-mode.h" |
| #include "mode.h" |
| #include "tempfile.h" |
| #include "kern_constants.h" |
| |
| #ifdef UML_CONFIG_MODE_SKAS |
| #include "skas.h" |
| #include "skas_ptrace.h" |
| #include "registers.h" |
| #endif |
| |
| static int ptrace_child(void *arg) |
| { |
| int ret; |
| int pid = os_getpid(), ppid = getppid(); |
| int sc_result; |
| |
| change_sig(SIGWINCH, 0); |
| if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){ |
| perror("ptrace"); |
| os_kill_process(pid, 0); |
| } |
| os_stop_process(pid); |
| |
| /*This syscall will be intercepted by the parent. Don't call more than |
| * once, please.*/ |
| sc_result = os_getpid(); |
| |
| if (sc_result == pid) |
| ret = 1; /*Nothing modified by the parent, we are running |
| normally.*/ |
| else if (sc_result == ppid) |
| ret = 0; /*Expected in check_ptrace and check_sysemu when they |
| succeed in modifying the stack frame*/ |
| else |
| ret = 2; /*Serious trouble! This could be caused by a bug in |
| host 2.6 SKAS3/2.6 patch before release -V6, together |
| with a bug in the UML code itself.*/ |
| _exit(ret); |
| } |
| |
| static int start_ptraced_child(void **stack_out) |
| { |
| void *stack; |
| unsigned long sp; |
| int pid, n, status; |
| |
| stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, |
| MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
| if(stack == MAP_FAILED) |
| panic("check_ptrace : mmap failed, errno = %d", errno); |
| sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *); |
| pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL); |
| if(pid < 0) |
| panic("start_ptraced_child : clone failed, errno = %d", errno); |
| CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); |
| if(n < 0) |
| panic("check_ptrace : clone failed, errno = %d", errno); |
| if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) |
| panic("check_ptrace : expected SIGSTOP, got status = %d", |
| status); |
| |
| *stack_out = stack; |
| return(pid); |
| } |
| |
| /* When testing for SYSEMU support, if it is one of the broken versions, we |
| * must just avoid using sysemu, not panic, but only if SYSEMU features are |
| * broken. |
| * So only for SYSEMU features we test mustpanic, while normal host features |
| * must work anyway! |
| */ |
| static int stop_ptraced_child(int pid, void *stack, int exitcode, |
| int mustpanic) |
| { |
| int status, n, ret = 0; |
| |
| if(ptrace(PTRACE_CONT, pid, 0, 0) < 0) |
| panic("check_ptrace : ptrace failed, errno = %d", errno); |
| CATCH_EINTR(n = waitpid(pid, &status, 0)); |
| if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) { |
| int exit_with = WEXITSTATUS(status); |
| if (exit_with == 2) |
| printf("check_ptrace : child exited with status 2. " |
| "Serious trouble happening! Try updating your " |
| "host skas patch!\nDisabling SYSEMU support."); |
| printf("check_ptrace : child exited with exitcode %d, while " |
| "expecting %d; status 0x%x", exit_with, |
| exitcode, status); |
| if (mustpanic) |
| panic("\n"); |
| else |
| printf("\n"); |
| ret = -1; |
| } |
| |
| if(munmap(stack, PAGE_SIZE) < 0) |
| panic("check_ptrace : munmap failed, errno = %d", errno); |
| return ret; |
| } |
| |
| int ptrace_faultinfo = 1; |
| int ptrace_ldt = 1; |
| int proc_mm = 1; |
| int skas_needs_stub = 0; |
| |
| static int __init skas0_cmd_param(char *str, int* add) |
| { |
| ptrace_faultinfo = proc_mm = 0; |
| return 0; |
| } |
| |
| /* The two __uml_setup would conflict, without this stupid alias. */ |
| |
| static int __init mode_skas0_cmd_param(char *str, int* add) |
| __attribute__((alias("skas0_cmd_param"))); |
| |
| __uml_setup("skas0", skas0_cmd_param, |
| "skas0\n" |
| " Disables SKAS3 usage, so that SKAS0 is used, unless \n" |
| " you specify mode=tt.\n\n"); |
| |
| __uml_setup("mode=skas0", mode_skas0_cmd_param, |
| "mode=skas0\n" |
| " Disables SKAS3 usage, so that SKAS0 is used, unless you \n" |
| " specify mode=tt. Note that this was recently added - on \n" |
| " older kernels you must use simply \"skas0\".\n\n"); |
| |
| static int force_sysemu_disabled = 0; |
| |
| static int __init nosysemu_cmd_param(char *str, int* add) |
| { |
| force_sysemu_disabled = 1; |
| return 0; |
| } |
| |
| __uml_setup("nosysemu", nosysemu_cmd_param, |
| "nosysemu\n" |
| " Turns off syscall emulation patch for ptrace (SYSEMU) on.\n" |
| " SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n" |
| " behaviour of ptrace() and helps reducing host context switch rate.\n" |
| " To make it working, you need a kernel patch for your host, too.\n" |
| " See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n" |
| " information.\n\n"); |
| |
| static void __init check_sysemu(void) |
| { |
| void *stack; |
| int pid, n, status, count=0; |
| |
| printf("Checking syscall emulation patch for ptrace..."); |
| sysemu_supported = 0; |
| pid = start_ptraced_child(&stack); |
| |
| if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0) |
| goto fail; |
| |
| CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); |
| if (n < 0) |
| panic("check_sysemu : wait failed, errno = %d", errno); |
| if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP)) |
| panic("check_sysemu : expected SIGTRAP, " |
| "got status = %d", status); |
| |
| n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET, |
| os_getpid()); |
| if(n < 0) |
| panic("check_sysemu : failed to modify system " |
| "call return, errno = %d", errno); |
| |
| if (stop_ptraced_child(pid, stack, 0, 0) < 0) |
| goto fail_stopped; |
| |
| sysemu_supported = 1; |
| printf("OK\n"); |
| set_using_sysemu(!force_sysemu_disabled); |
| |
| printf("Checking advanced syscall emulation patch for ptrace..."); |
| pid = start_ptraced_child(&stack); |
| |
| if(ptrace(PTRACE_OLDSETOPTIONS, pid, 0, |
| (void *) PTRACE_O_TRACESYSGOOD) < 0) |
| panic("check_ptrace: PTRACE_OLDSETOPTIONS failed, errno = %d", |
| errno); |
| |
| while(1){ |
| count++; |
| if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0) |
| goto fail; |
| CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); |
| if(n < 0) |
| panic("check_ptrace : wait failed, errno = %d", errno); |
| if(WIFSTOPPED(status) && (WSTOPSIG(status) == (SIGTRAP|0x80))){ |
| if (!count) |
| panic("check_ptrace : SYSEMU_SINGLESTEP " |
| "doesn't singlestep"); |
| n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET, |
| os_getpid()); |
| if(n < 0) |
| panic("check_sysemu : failed to modify system " |
| "call return, errno = %d", errno); |
| break; |
| } |
| else if(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP)) |
| count++; |
| else |
| panic("check_ptrace : expected SIGTRAP or " |
| "(SIGTRAP|0x80), got status = %d", status); |
| } |
| if (stop_ptraced_child(pid, stack, 0, 0) < 0) |
| goto fail_stopped; |
| |
| sysemu_supported = 2; |
| printf("OK\n"); |
| |
| if ( !force_sysemu_disabled ) |
| set_using_sysemu(sysemu_supported); |
| return; |
| |
| fail: |
| stop_ptraced_child(pid, stack, 1, 0); |
| fail_stopped: |
| printf("missing\n"); |
| } |
| |
| static void __init check_ptrace(void) |
| { |
| void *stack; |
| int pid, syscall, n, status; |
| |
| printf("Checking that ptrace can change system call numbers..."); |
| pid = start_ptraced_child(&stack); |
| |
| if(ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0) |
| panic("check_ptrace: PTRACE_OLDSETOPTIONS failed, errno = %d", errno); |
| |
| while(1){ |
| if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0) |
| panic("check_ptrace : ptrace failed, errno = %d", |
| errno); |
| CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); |
| if(n < 0) |
| panic("check_ptrace : wait failed, errno = %d", errno); |
| if(!WIFSTOPPED(status) || (WSTOPSIG(status) != (SIGTRAP|0x80))) |
| panic("check_ptrace : expected (SIGTRAP|0x80), " |
| "got status = %d", status); |
| |
| syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET, |
| 0); |
| if(syscall == __NR_getpid){ |
| n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, |
| __NR_getppid); |
| if(n < 0) |
| panic("check_ptrace : failed to modify system " |
| "call, errno = %d", errno); |
| break; |
| } |
| } |
| stop_ptraced_child(pid, stack, 0, 1); |
| printf("OK\n"); |
| check_sysemu(); |
| } |
| |
| extern int create_tmp_file(unsigned long long len); |
| |
| static void check_tmpexec(void) |
| { |
| void *addr; |
| int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE); |
| |
| addr = mmap(NULL, UM_KERN_PAGE_SIZE, |
| PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0); |
| printf("Checking PROT_EXEC mmap in /tmp..."); |
| fflush(stdout); |
| if(addr == MAP_FAILED){ |
| err = errno; |
| perror("failed"); |
| if(err == EPERM) |
| printf("/tmp must be not mounted noexec\n"); |
| exit(1); |
| } |
| printf("OK\n"); |
| munmap(addr, UM_KERN_PAGE_SIZE); |
| |
| close(fd); |
| } |
| |
| void os_early_checks(void) |
| { |
| check_ptrace(); |
| |
| /* Need to check this early because mmapping happens before the |
| * kernel is running. |
| */ |
| check_tmpexec(); |
| } |
| |
| static int __init noprocmm_cmd_param(char *str, int* add) |
| { |
| proc_mm = 0; |
| return 0; |
| } |
| |
| __uml_setup("noprocmm", noprocmm_cmd_param, |
| "noprocmm\n" |
| " Turns off usage of /proc/mm, even if host supports it.\n" |
| " To support /proc/mm, the host needs to be patched using\n" |
| " the current skas3 patch.\n\n"); |
| |
| static int __init noptracefaultinfo_cmd_param(char *str, int* add) |
| { |
| ptrace_faultinfo = 0; |
| return 0; |
| } |
| |
| __uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param, |
| "noptracefaultinfo\n" |
| " Turns off usage of PTRACE_FAULTINFO, even if host supports\n" |
| " it. To support PTRACE_FAULTINFO, the host needs to be patched\n" |
| " using the current skas3 patch.\n\n"); |
| |
| static int __init noptraceldt_cmd_param(char *str, int* add) |
| { |
| ptrace_ldt = 0; |
| return 0; |
| } |
| |
| __uml_setup("noptraceldt", noptraceldt_cmd_param, |
| "noptraceldt\n" |
| " Turns off usage of PTRACE_LDT, even if host supports it.\n" |
| " To support PTRACE_LDT, the host needs to be patched using\n" |
| " the current skas3 patch.\n\n"); |
| |
| #ifdef UML_CONFIG_MODE_SKAS |
| static inline void check_skas3_ptrace_faultinfo(void) |
| { |
| struct ptrace_faultinfo fi; |
| void *stack; |
| int pid, n; |
| |
| printf(" - PTRACE_FAULTINFO..."); |
| pid = start_ptraced_child(&stack); |
| |
| n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi); |
| if (n < 0) { |
| ptrace_faultinfo = 0; |
| if(errno == EIO) |
| printf("not found\n"); |
| else |
| perror("not found"); |
| } |
| else { |
| if (!ptrace_faultinfo) |
| printf("found but disabled on command line\n"); |
| else |
| printf("found\n"); |
| } |
| |
| init_registers(pid); |
| stop_ptraced_child(pid, stack, 1, 1); |
| } |
| |
| static inline void check_skas3_ptrace_ldt(void) |
| { |
| #ifdef PTRACE_LDT |
| void *stack; |
| int pid, n; |
| unsigned char ldtbuf[40]; |
| struct ptrace_ldt ldt_op = (struct ptrace_ldt) { |
| .func = 2, /* read default ldt */ |
| .ptr = ldtbuf, |
| .bytecount = sizeof(ldtbuf)}; |
| |
| printf(" - PTRACE_LDT..."); |
| pid = start_ptraced_child(&stack); |
| |
| n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op); |
| if (n < 0) { |
| if(errno == EIO) |
| printf("not found\n"); |
| else { |
| perror("not found"); |
| } |
| ptrace_ldt = 0; |
| } |
| else { |
| if(ptrace_ldt) |
| printf("found\n"); |
| else |
| printf("found, but use is disabled\n"); |
| } |
| |
| stop_ptraced_child(pid, stack, 1, 1); |
| #else |
| /* PTRACE_LDT might be disabled via cmdline option. |
| * We want to override this, else we might use the stub |
| * without real need |
| */ |
| ptrace_ldt = 1; |
| #endif |
| } |
| |
| static inline void check_skas3_proc_mm(void) |
| { |
| printf(" - /proc/mm..."); |
| if (os_access("/proc/mm", OS_ACC_W_OK) < 0) { |
| proc_mm = 0; |
| printf("not found\n"); |
| } |
| else { |
| if (!proc_mm) |
| printf("found but disabled on command line\n"); |
| else |
| printf("found\n"); |
| } |
| } |
| |
| int can_do_skas(void) |
| { |
| printf("Checking for the skas3 patch in the host:\n"); |
| |
| check_skas3_proc_mm(); |
| check_skas3_ptrace_faultinfo(); |
| check_skas3_ptrace_ldt(); |
| |
| if(!proc_mm || !ptrace_faultinfo || !ptrace_ldt) |
| skas_needs_stub = 1; |
| |
| return 1; |
| } |
| #else |
| int can_do_skas(void) |
| { |
| return(0); |
| } |
| #endif |
| |
| int have_devanon = 0; |
| |
| /* Runs on boot kernel stack - already safe to use printk. */ |
| |
| void check_devanon(void) |
| { |
| int fd; |
| |
| printk("Checking for /dev/anon on the host..."); |
| fd = open("/dev/anon", O_RDWR); |
| if(fd < 0){ |
| printk("Not available (open failed with errno %d)\n", errno); |
| return; |
| } |
| |
| printk("OK\n"); |
| have_devanon = 1; |
| } |
| |
| int __init parse_iomem(char *str, int *add) |
| { |
| struct iomem_region *new; |
| struct uml_stat buf; |
| char *file, *driver; |
| int fd, err, size; |
| |
| driver = str; |
| file = strchr(str,','); |
| if(file == NULL){ |
| printf("parse_iomem : failed to parse iomem\n"); |
| goto out; |
| } |
| *file = '\0'; |
| file++; |
| fd = os_open_file(file, of_rdwr(OPENFLAGS()), 0); |
| if(fd < 0){ |
| os_print_error(fd, "parse_iomem - Couldn't open io file"); |
| goto out; |
| } |
| |
| err = os_stat_fd(fd, &buf); |
| if(err < 0){ |
| os_print_error(err, "parse_iomem - cannot stat_fd file"); |
| goto out_close; |
| } |
| |
| new = malloc(sizeof(*new)); |
| if(new == NULL){ |
| perror("Couldn't allocate iomem_region struct"); |
| goto out_close; |
| } |
| |
| size = (buf.ust_size + UM_KERN_PAGE_SIZE) & ~(UM_KERN_PAGE_SIZE - 1); |
| |
| *new = ((struct iomem_region) { .next = iomem_regions, |
| .driver = driver, |
| .fd = fd, |
| .size = size, |
| .phys = 0, |
| .virt = 0 }); |
| iomem_regions = new; |
| iomem_size += new->size + UM_KERN_PAGE_SIZE; |
| |
| return(0); |
| out_close: |
| os_close_file(fd); |
| out: |
| return(1); |
| } |
| |
| |
| /* Changed during early boot */ |
| int pty_output_sigio = 0; |
| int pty_close_sigio = 0; |
| |
| /* Used as a flag during SIGIO testing early in boot */ |
| static volatile int got_sigio = 0; |
| |
| static void __init handler(int sig) |
| { |
| got_sigio = 1; |
| } |
| |
| struct openpty_arg { |
| int master; |
| int slave; |
| int err; |
| }; |
| |
| static void openpty_cb(void *arg) |
| { |
| struct openpty_arg *info = arg; |
| |
| info->err = 0; |
| if(openpty(&info->master, &info->slave, NULL, NULL, NULL)) |
| info->err = -errno; |
| } |
| |
| static void __init check_one_sigio(void (*proc)(int, int)) |
| { |
| struct sigaction old, new; |
| struct openpty_arg pty = { .master = -1, .slave = -1 }; |
| int master, slave, err; |
| |
| initial_thread_cb(openpty_cb, &pty); |
| if(pty.err){ |
| printk("openpty failed, errno = %d\n", -pty.err); |
| return; |
| } |
| |
| master = pty.master; |
| slave = pty.slave; |
| |
| if((master == -1) || (slave == -1)){ |
| printk("openpty failed to allocate a pty\n"); |
| return; |
| } |
| |
| /* Not now, but complain so we now where we failed. */ |
| err = raw(master); |
| if (err < 0) |
| panic("check_sigio : __raw failed, errno = %d\n", -err); |
| |
| err = os_sigio_async(master, slave); |
| if(err < 0) |
| panic("tty_fds : sigio_async failed, err = %d\n", -err); |
| |
| if(sigaction(SIGIO, NULL, &old) < 0) |
| panic("check_sigio : sigaction 1 failed, errno = %d\n", errno); |
| new = old; |
| new.sa_handler = handler; |
| if(sigaction(SIGIO, &new, NULL) < 0) |
| panic("check_sigio : sigaction 2 failed, errno = %d\n", errno); |
| |
| got_sigio = 0; |
| (*proc)(master, slave); |
| |
| close(master); |
| close(slave); |
| |
| if(sigaction(SIGIO, &old, NULL) < 0) |
| panic("check_sigio : sigaction 3 failed, errno = %d\n", errno); |
| } |
| |
| static void tty_output(int master, int slave) |
| { |
| int n; |
| char buf[512]; |
| |
| printk("Checking that host ptys support output SIGIO..."); |
| |
| memset(buf, 0, sizeof(buf)); |
| |
| while(os_write_file(master, buf, sizeof(buf)) > 0) ; |
| if(errno != EAGAIN) |
| panic("check_sigio : write failed, errno = %d\n", errno); |
| while(((n = os_read_file(slave, buf, sizeof(buf))) > 0) && !got_sigio) ; |
| |
| if(got_sigio){ |
| printk("Yes\n"); |
| pty_output_sigio = 1; |
| } |
| else if(n == -EAGAIN) printk("No, enabling workaround\n"); |
| else panic("check_sigio : read failed, err = %d\n", n); |
| } |
| |
| static void tty_close(int master, int slave) |
| { |
| printk("Checking that host ptys support SIGIO on close..."); |
| |
| close(slave); |
| if(got_sigio){ |
| printk("Yes\n"); |
| pty_close_sigio = 1; |
| } |
| else printk("No, enabling workaround\n"); |
| } |
| |
| void __init check_sigio(void) |
| { |
| if((os_access("/dev/ptmx", OS_ACC_R_OK) < 0) && |
| (os_access("/dev/ptyp0", OS_ACC_R_OK) < 0)){ |
| printk("No pseudo-terminals available - skipping pty SIGIO " |
| "check\n"); |
| return; |
| } |
| check_one_sigio(tty_output); |
| check_one_sigio(tty_close); |
| } |
| |
| void os_check_bugs(void) |
| { |
| check_ptrace(); |
| check_sigio(); |
| check_devanon(); |
| } |
| |