diff options
Diffstat (limited to 'fs/exec.c')
| -rw-r--r-- | fs/exec.c | 688 |
1 files changed, 7 insertions, 681 deletions
diff --git a/fs/exec.c b/fs/exec.c index 574cf4de4ec..48fb26ef8a1 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -66,19 +66,8 @@ #include <trace/events/sched.h> -int core_uses_pid; -char core_pattern[CORENAME_MAX_SIZE] = "core"; -unsigned int core_pipe_limit; int suid_dumpable = 0; -struct core_name { - char *corename; - int used, size; -}; -static atomic_t call_count = ATOMIC_INIT(1); - -/* The maximal length of core_pattern is also specified in sysctl.c */ - static LIST_HEAD(formats); static DEFINE_RWLOCK(binfmt_lock); @@ -1006,40 +995,6 @@ no_thread_group: return 0; } -/* - * These functions flushes out all traces of the currently running executable - * so that a new one can be started - */ -static void flush_old_files(struct files_struct * files) -{ - long j = -1; - struct fdtable *fdt; - - spin_lock(&files->file_lock); - for (;;) { - unsigned long set, i; - - j++; - i = j * BITS_PER_LONG; - fdt = files_fdtable(files); - if (i >= fdt->max_fds) - break; - set = fdt->close_on_exec[j]; - if (!set) - continue; - fdt->close_on_exec[j] = 0; - spin_unlock(&files->file_lock); - for ( ; set ; i++,set >>= 1) { - if (set & 1) { - sys_close(i); - } - } - spin_lock(&files->file_lock); - - } - spin_unlock(&files->file_lock); -} - char *get_task_comm(char *buf, struct task_struct *tsk) { /* buf must be at least sizeof(tsk->comm) in size */ @@ -1050,6 +1005,11 @@ char *get_task_comm(char *buf, struct task_struct *tsk) } EXPORT_SYMBOL_GPL(get_task_comm); +/* + * These functions flushes out all traces of the currently running executable + * so that a new one can be started + */ + void set_task_comm(struct task_struct *tsk, char *buf) { task_lock(tsk); @@ -1171,7 +1131,7 @@ void setup_new_exec(struct linux_binprm * bprm) current->self_exec_id++; flush_signal_handlers(current, 0); - flush_old_files(current->files); + do_close_on_exec(current->files); } EXPORT_SYMBOL(setup_new_exec); @@ -1632,353 +1592,6 @@ void set_binfmt(struct linux_binfmt *new) EXPORT_SYMBOL(set_binfmt); -static int expand_corename(struct core_name *cn) -{ - char *old_corename = cn->corename; - - cn->size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count); - cn->corename = krealloc(old_corename, cn->size, GFP_KERNEL); - - if (!cn->corename) { - kfree(old_corename); - return -ENOMEM; - } - - return 0; -} - -static int cn_printf(struct core_name *cn, const char *fmt, ...) -{ - char *cur; - int need; - int ret; - va_list arg; - - va_start(arg, fmt); - need = vsnprintf(NULL, 0, fmt, arg); - va_end(arg); - - if (likely(need < cn->size - cn->used - 1)) - goto out_printf; - - ret = expand_corename(cn); - if (ret) - goto expand_fail; - -out_printf: - cur = cn->corename + cn->used; - va_start(arg, fmt); - vsnprintf(cur, need + 1, fmt, arg); - va_end(arg); - cn->used += need; - return 0; - -expand_fail: - return ret; -} - -static void cn_escape(char *str) -{ - for (; *str; str++) - if (*str == '/') - *str = '!'; -} - -static int cn_print_exe_file(struct core_name *cn) -{ - struct file *exe_file; - char *pathbuf, *path; - int ret; - - exe_file = get_mm_exe_file(current->mm); - if (!exe_file) { - char *commstart = cn->corename + cn->used; - ret = cn_printf(cn, "%s (path unknown)", current->comm); - cn_escape(commstart); - return ret; - } - - pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY); - if (!pathbuf) { - ret = -ENOMEM; - goto put_exe_file; - } - - path = d_path(&exe_file->f_path, pathbuf, PATH_MAX); - if (IS_ERR(path)) { - ret = PTR_ERR(path); - goto free_buf; - } - - cn_escape(path); - - ret = cn_printf(cn, "%s", path); - -free_buf: - kfree(pathbuf); -put_exe_file: - fput(exe_file); - return ret; -} - -/* format_corename will inspect the pattern parameter, and output a - * name into corename, which must have space for at least - * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. - */ -static int format_corename(struct core_name *cn, long signr) -{ - const struct cred *cred = current_cred(); - const char *pat_ptr = core_pattern; - int ispipe = (*pat_ptr == '|'); - int pid_in_pattern = 0; - int err = 0; - - cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count); - cn->corename = kmalloc(cn->size, GFP_KERNEL); - cn->used = 0; - - if (!cn->corename) - return -ENOMEM; - - /* Repeat as long as we have more pattern to process and more output - space */ - while (*pat_ptr) { - if (*pat_ptr != '%') { - if (*pat_ptr == 0) - goto out; - err = cn_printf(cn, "%c", *pat_ptr++); - } else { - switch (*++pat_ptr) { - /* single % at the end, drop that */ - case 0: - goto out; - /* Double percent, output one percent */ - case '%': - err = cn_printf(cn, "%c", '%'); - break; - /* pid */ - case 'p': - pid_in_pattern = 1; - err = cn_printf(cn, "%d", - task_tgid_vnr(current)); - break; - /* uid */ - case 'u': - err = cn_printf(cn, "%d", cred->uid); - break; - /* gid */ - case 'g': - err = cn_printf(cn, "%d", cred->gid); - break; - /* signal that caused the coredump */ - case 's': - err = cn_printf(cn, "%ld", signr); - break; - /* UNIX time of coredump */ - case 't': { - struct timeval tv; - do_gettimeofday(&tv); - err = cn_printf(cn, "%lu", tv.tv_sec); - break; - } - /* hostname */ - case 'h': { - char *namestart = cn->corename + cn->used; - down_read(&uts_sem); - err = cn_printf(cn, "%s", - utsname()->nodename); - up_read(&uts_sem); - cn_escape(namestart); - break; - } - /* executable */ - case 'e': { - char *commstart = cn->corename + cn->used; - err = cn_printf(cn, "%s", current->comm); - cn_escape(commstart); - break; - } - case 'E': - err = cn_print_exe_file(cn); - break; - /* core limit size */ - case 'c': - err = cn_printf(cn, "%lu", - rlimit(RLIMIT_CORE)); - break; - default: - break; - } - ++pat_ptr; - } - - if (err) - return err; - } - - /* Backward compatibility with core_uses_pid: - * - * If core_pattern does not include a %p (as is the default) - * and core_uses_pid is set, then .%pid will be appended to - * the filename. Do not do this for piped commands. */ - if (!ispipe && !pid_in_pattern && core_uses_pid) { - err = cn_printf(cn, ".%d", task_tgid_vnr(current)); - if (err) - return err; - } -out: - return ispipe; -} - -static int zap_process(struct task_struct *start, int exit_code) -{ - struct task_struct *t; - int nr = 0; - - start->signal->flags = SIGNAL_GROUP_EXIT; - start->signal->group_exit_code = exit_code; - start->signal->group_stop_count = 0; - - t = start; - do { - task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); - if (t != current && t->mm) { - sigaddset(&t->pending.signal, SIGKILL); - signal_wake_up(t, 1); - nr++; - } - } while_each_thread(start, t); - - return nr; -} - -static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, - struct core_state *core_state, int exit_code) -{ - struct task_struct *g, *p; - unsigned long flags; - int nr = -EAGAIN; - - spin_lock_irq(&tsk->sighand->siglock); - if (!signal_group_exit(tsk->signal)) { - mm->core_state = core_state; - nr = zap_process(tsk, exit_code); - } - spin_unlock_irq(&tsk->sighand->siglock); - if (unlikely(nr < 0)) - return nr; - - if (atomic_read(&mm->mm_users) == nr + 1) - goto done; - /* - * We should find and kill all tasks which use this mm, and we should - * count them correctly into ->nr_threads. We don't take tasklist - * lock, but this is safe wrt: - * - * fork: - * None of sub-threads can fork after zap_process(leader). All - * processes which were created before this point should be - * visible to zap_threads() because copy_process() adds the new - * process to the tail of init_task.tasks list, and lock/unlock - * of ->siglock provides a memory barrier. - * - * do_exit: - * The caller holds mm->mmap_sem. This means that the task which - * uses this mm can't pass exit_mm(), so it can't exit or clear - * its ->mm. - * - * de_thread: - * It does list_replace_rcu(&leader->tasks, ¤t->tasks), - * we must see either old or new leader, this does not matter. - * However, it can change p->sighand, so lock_task_sighand(p) - * must be used. Since p->mm != NULL and we hold ->mmap_sem - * it can't fail. - * - * Note also that "g" can be the old leader with ->mm == NULL - * and already unhashed and thus removed from ->thread_group. - * This is OK, __unhash_process()->list_del_rcu() does not - * clear the ->next pointer, we will find the new leader via - * next_thread(). - */ - rcu_read_lock(); - for_each_process(g) { - if (g == tsk->group_leader) - continue; - if (g->flags & PF_KTHREAD) - continue; - p = g; - do { - if (p->mm) { - if (unlikely(p->mm == mm)) { - lock_task_sighand(p, &flags); - nr += zap_process(p, exit_code); - unlock_task_sighand(p, &flags); - } - break; - } - } while_each_thread(g, p); - } - rcu_read_unlock(); -done: - atomic_set(&core_state->nr_threads, nr); - return nr; -} - -static int coredump_wait(int exit_code, struct core_state *core_state) -{ - struct task_struct *tsk = current; - struct mm_struct *mm = tsk->mm; - int core_waiters = -EBUSY; - - init_completion(&core_state->startup); - core_state->dumper.task = tsk; - core_state->dumper.next = NULL; - - down_write(&mm->mmap_sem); - if (!mm->core_state) - core_waiters = zap_threads(tsk, mm, core_state, exit_code); - up_write(&mm->mmap_sem); - - if (core_waiters > 0) { - struct core_thread *ptr; - - wait_for_completion(&core_state->startup); - /* - * Wait for all the threads to become inactive, so that - * all the thread context (extended register state, like - * fpu etc) gets copied to the memory. - */ - ptr = core_state->dumper.next; - while (ptr != NULL) { - wait_task_inactive(ptr->task, 0); - ptr = ptr->next; - } - } - - return core_waiters; -} - -static void coredump_finish(struct mm_struct *mm) -{ - struct core_thread *curr, *next; - struct task_struct *task; - - next = mm->core_state->dumper.next; - while ((curr = next) != NULL) { - next = curr->next; - task = curr->task; - /* - * see exit_mm(), curr->task must not see - * ->task == NULL before we read ->next. - */ - smp_mb(); - curr->task = NULL; - wake_up_process(task); - } - - mm->core_state = NULL; -} - /* * set_dumpable converts traditional three-value dumpable to two flags and * stores them into mm->flags. It modifies lower two bits of mm->flags, but @@ -2020,7 +1633,7 @@ void set_dumpable(struct mm_struct *mm, int value) } } -static int __get_dumpable(unsigned long mm_flags) +int __get_dumpable(unsigned long mm_flags) { int ret; @@ -2032,290 +1645,3 @@ int get_dumpable(struct mm_struct *mm) { return __get_dumpable(mm->flags); } - -static void wait_for_dump_helpers(struct file *file) -{ - struct pipe_inode_info *pipe; - - pipe = file->f_path.dentry->d_inode->i_pipe; - - pipe_lock(pipe); - pipe->readers++; - pipe->writers--; - - while ((pipe->readers > 1) && (!signal_pending(current))) { - wake_up_interruptible_sync(&pipe->wait); - kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); - pipe_wait(pipe); - } - - pipe->readers--; - pipe->writers++; - pipe_unlock(pipe); - -} - - -/* - * umh_pipe_setup - * helper function to customize the process used - * to collect the core in userspace. Specifically - * it sets up a pipe and installs it as fd 0 (stdin) - * for the process. Returns 0 on success, or - * PTR_ERR on failure. - * Note that it also sets the core limit to 1. This - * is a special value that we use to trap recursive - * core dumps - */ -static int umh_pipe_setup(struct subprocess_info *info, struct cred *new) -{ - struct file *files[2]; - struct fdtable *fdt; - struct coredump_params *cp = (struct coredump_params *)info->data; - struct files_struct *cf = current->files; - int err = create_pipe_files(files, 0); - if (err) - return err; - - cp->file = files[1]; - - sys_close(0); - fd_install(0, files[0]); - spin_lock(&cf->file_lock); - fdt = files_fdtable(cf); - __set_open_fd(0, fdt); - __clear_close_on_exec(0, fdt); - spin_unlock(&cf->file_lock); - - /* and disallow core files too */ - current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; - - return 0; -} - -void do_coredump(long signr, int exit_code, struct pt_regs *regs) -{ - struct core_state core_state; - struct core_name cn; - struct mm_struct *mm = current->mm; - struct linux_binfmt * binfmt; - const struct cred *old_cred; - struct cred *cred; - int retval = 0; - int flag = 0; - int ispipe; - bool need_nonrelative = false; - static atomic_t core_dump_count = ATOMIC_INIT(0); - struct coredump_params cprm = { - .signr = signr, - .regs = regs, - .limit = rlimit(RLIMIT_CORE), - /* - * We must use the same mm->flags while dumping core to avoid - * inconsistency of bit flags, since this flag is not protected - * by any locks. - */ - .mm_flags = mm->flags, - }; - - audit_core_dumps(signr); - - binfmt = mm->binfmt; - if (!binfmt || !binfmt->core_dump) - goto fail; - if (!__get_dumpable(cprm.mm_flags)) - goto fail; - - cred = prepare_creds(); - if (!cred) - goto fail; - /* - * We cannot trust fsuid as being the "true" uid of the process - * nor do we know its entire history. We only know it was tainted - * so we dump it as root in mode 2, and only into a controlled - * environment (pipe handler or fully qualified path). - */ - if (__get_dumpable(cprm.mm_flags) == SUID_DUMPABLE_SAFE) { - /* Setuid core dump mode */ - flag = O_EXCL; /* Stop rewrite attacks */ - cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */ - need_nonrelative = true; - } - - retval = coredump_wait(exit_code, &core_state); - if (retval < 0) - goto fail_creds; - - old_cred = override_creds(cred); - - /* - * Clear any false indication of pending signals that might - * be seen by the filesystem code called to write the core file. - */ - clear_thread_flag(TIF_SIGPENDING); - - ispipe = format_corename(&cn, signr); - - if (ispipe) { - int dump_count; - char **helper_argv; - - if (ispipe < 0) { - printk(KERN_WARNING "format_corename failed\n"); - printk(KERN_WARNING "Aborting core\n"); - goto fail_corename; - } - - if (cprm.limit == 1) { - /* See umh_pipe_setup() which sets RLIMIT_CORE = 1. - * - * Normally core limits are irrelevant to pipes, since - * we're not writing to the file system, but we use - * cprm.limit of 1 here as a speacial value, this is a - * consistent way to catch recursive crashes. - * We can still crash if the core_pattern binary sets - * RLIM_CORE = !1, but it runs as root, and can do - * lots of stupid things. - * - * Note that we use task_tgid_vnr here to grab the pid - * of the process group leader. That way we get the - * right pid if a thread in a multi-threaded - * core_pattern process dies. - */ - printk(KERN_WARNING - "Process %d(%s) has RLIMIT_CORE set to 1\n", - task_tgid_vnr(current), current->comm); - printk(KERN_WARNING "Aborting core\n"); - goto fail_unlock; - } - cprm.limit = RLIM_INFINITY; - - dump_count = atomic_inc_return(&core_dump_count); - if (core_pipe_limit && (core_pipe_limit < dump_count)) { - printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", - task_tgid_vnr(current), current->comm); - printk(KERN_WARNING "Skipping core dump\n"); - goto fail_dropcount; - } - - helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL); - if (!helper_argv) { - printk(KERN_WARNING "%s failed to allocate memory\n", - __func__); - goto fail_dropcount; - } - - retval = call_usermodehelper_fns(helper_argv[0], helper_argv, - NULL, UMH_WAIT_EXEC, umh_pipe_setup, - NULL, &cprm); - argv_free(helper_argv); - if (retval) { - printk(KERN_INFO "Core dump to %s pipe failed\n", - cn.corename); - goto close_fail; - } - } else { - struct inode *inode; - - if (cprm.limit < binfmt->min_coredump) - goto fail_unlock; - - if (need_nonrelative && cn.corename[0] != '/') { - printk(KERN_WARNING "Pid %d(%s) can only dump core "\ - "to fully qualified path!\n", - task_tgid_vnr(current), current->comm); - printk(KERN_WARNING "Skipping core dump\n"); - goto fail_unlock; - } - - cprm.file = filp_open(cn.corename, - O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, - 0600); - if (IS_ERR(cprm.file)) - goto fail_unlock; - - inode = cprm.file->f_path.dentry->d_inode; - if (inode->i_nlink > 1) - goto close_fail; - if (d_unhashed(cprm.file->f_path.dentry)) - goto close_fail; - /* - * AK: actually i see no reason to not allow this for named - * pipes etc, but keep the previous behaviour for now. - */ - if (!S_ISREG(inode->i_mode)) - goto close_fail; - /* - * Dont allow local users get cute and trick others to coredump - * into their pre-created files. - */ - if (!uid_eq(inode->i_uid, current_fsuid())) - goto close_fail; - if (!cprm.file->f_op || !cprm.file->f_op->write) - goto close_fail; - if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file)) - goto close_fail; - } - - retval = binfmt->core_dump(&cprm); - if (retval) - current->signal->group_exit_code |= 0x80; - - if (ispipe && core_pipe_limit) - wait_for_dump_helpers(cprm.file); -close_fail: - if (cprm.file) - filp_close(cprm.file, NULL); -fail_dropcount: - if (ispipe) - atomic_dec(&core_dump_count); -fail_unlock: - kfree(cn.corename); -fail_corename: - coredump_finish(mm); - revert_creds(old_cred); -fail_creds: - put_cred(cred); -fail: - return; -} - -/* - * Core dumping helper functions. These are the only things you should - * do on a core-file: use only these functions to write out all the - * necessary info. - */ -int dump_write(struct file *file, const void *addr, int nr) -{ - return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr; -} -EXPORT_SYMBOL(dump_write); - -int dump_seek(struct file *file, loff_t off) -{ - int ret = 1; - - if (file->f_op->llseek && file->f_op->llseek != no_llseek) { - if (file->f_op->llseek(file, off, SEEK_CUR) < 0) - return 0; - } else { - char *buf = (char *)get_zeroed_page(GFP_KERNEL); - - if (!buf) - return 0; - while (off > 0) { - unsigned long n = off; - - if (n > PAGE_SIZE) - n = PAGE_SIZE; - if (!dump_write(file, buf, n)) { - ret = 0; - break; - } - off -= n; - } - free_page((unsigned long)buf); - } - return ret; -} -EXPORT_SYMBOL(dump_seek); |