coredump: move core dump functionality into its own file
This prepares for making core dump functionality optional. The variable "suid_dumpable" and associated functions are left in fs/exec.c because they're used elsewhere, such as in ptrace. Signed-off-by: Alex Kelly <alex.page.kelly@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Alex Kelly
Al Viro
parent
f34f9d186d
commit
10c28d937e
4 changed files with 689 additions and 645 deletions
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@ -11,7 +11,7 @@ obj-y := open.o read_write.o file_table.o super.o \
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attr.o bad_inode.o file.o filesystems.o namespace.o \
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seq_file.o xattr.o libfs.o fs-writeback.o \
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pnode.o drop_caches.o splice.o sync.o utimes.o \
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stack.o fs_struct.o statfs.o
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stack.o fs_struct.o statfs.o coredump.o
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ifeq ($(CONFIG_BLOCK),y)
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obj-y += buffer.o bio.o block_dev.o direct-io.o mpage.o ioprio.o
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686
fs/coredump.c
Normal file
686
fs/coredump.c
Normal file
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@ -0,0 +1,686 @@
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#include <linux/slab.h>
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#include <linux/file.h>
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#include <linux/fdtable.h>
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#include <linux/mm.h>
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#include <linux/stat.h>
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#include <linux/fcntl.h>
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#include <linux/swap.h>
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#include <linux/string.h>
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#include <linux/init.h>
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#include <linux/pagemap.h>
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#include <linux/perf_event.h>
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#include <linux/highmem.h>
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#include <linux/spinlock.h>
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#include <linux/key.h>
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#include <linux/personality.h>
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#include <linux/binfmts.h>
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#include <linux/utsname.h>
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#include <linux/pid_namespace.h>
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#include <linux/module.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/tsacct_kern.h>
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#include <linux/cn_proc.h>
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#include <linux/audit.h>
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#include <linux/tracehook.h>
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#include <linux/kmod.h>
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#include <linux/fsnotify.h>
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#include <linux/fs_struct.h>
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#include <linux/pipe_fs_i.h>
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#include <linux/oom.h>
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#include <linux/compat.h>
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#include <asm/uaccess.h>
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#include <asm/mmu_context.h>
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#include <asm/tlb.h>
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#include <asm/exec.h>
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#include <trace/events/task.h>
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#include "internal.h"
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#include <trace/events/sched.h>
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int core_uses_pid;
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char core_pattern[CORENAME_MAX_SIZE] = "core";
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unsigned int core_pipe_limit;
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struct core_name {
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char *corename;
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int used, size;
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};
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static atomic_t call_count = ATOMIC_INIT(1);
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/* The maximal length of core_pattern is also specified in sysctl.c */
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static int expand_corename(struct core_name *cn)
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{
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char *old_corename = cn->corename;
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cn->size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count);
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cn->corename = krealloc(old_corename, cn->size, GFP_KERNEL);
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if (!cn->corename) {
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kfree(old_corename);
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return -ENOMEM;
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}
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return 0;
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}
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static int cn_printf(struct core_name *cn, const char *fmt, ...)
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{
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char *cur;
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int need;
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int ret;
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va_list arg;
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va_start(arg, fmt);
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need = vsnprintf(NULL, 0, fmt, arg);
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va_end(arg);
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if (likely(need < cn->size - cn->used - 1))
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goto out_printf;
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ret = expand_corename(cn);
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if (ret)
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goto expand_fail;
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out_printf:
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cur = cn->corename + cn->used;
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va_start(arg, fmt);
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vsnprintf(cur, need + 1, fmt, arg);
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va_end(arg);
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cn->used += need;
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return 0;
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expand_fail:
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return ret;
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}
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static void cn_escape(char *str)
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{
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for (; *str; str++)
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if (*str == '/')
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*str = '!';
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}
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static int cn_print_exe_file(struct core_name *cn)
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{
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struct file *exe_file;
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char *pathbuf, *path;
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int ret;
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exe_file = get_mm_exe_file(current->mm);
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if (!exe_file) {
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char *commstart = cn->corename + cn->used;
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ret = cn_printf(cn, "%s (path unknown)", current->comm);
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cn_escape(commstart);
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return ret;
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}
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pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY);
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if (!pathbuf) {
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ret = -ENOMEM;
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goto put_exe_file;
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}
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path = d_path(&exe_file->f_path, pathbuf, PATH_MAX);
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if (IS_ERR(path)) {
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ret = PTR_ERR(path);
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goto free_buf;
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}
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cn_escape(path);
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ret = cn_printf(cn, "%s", path);
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free_buf:
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kfree(pathbuf);
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put_exe_file:
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fput(exe_file);
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return ret;
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}
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/* format_corename will inspect the pattern parameter, and output a
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* name into corename, which must have space for at least
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* CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
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*/
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static int format_corename(struct core_name *cn, long signr)
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{
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const struct cred *cred = current_cred();
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const char *pat_ptr = core_pattern;
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int ispipe = (*pat_ptr == '|');
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int pid_in_pattern = 0;
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int err = 0;
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cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count);
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cn->corename = kmalloc(cn->size, GFP_KERNEL);
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cn->used = 0;
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if (!cn->corename)
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return -ENOMEM;
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/* Repeat as long as we have more pattern to process and more output
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space */
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while (*pat_ptr) {
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if (*pat_ptr != '%') {
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if (*pat_ptr == 0)
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goto out;
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err = cn_printf(cn, "%c", *pat_ptr++);
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} else {
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switch (*++pat_ptr) {
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/* single % at the end, drop that */
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case 0:
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goto out;
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/* Double percent, output one percent */
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case '%':
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err = cn_printf(cn, "%c", '%');
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break;
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/* pid */
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case 'p':
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pid_in_pattern = 1;
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err = cn_printf(cn, "%d",
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task_tgid_vnr(current));
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break;
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/* uid */
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case 'u':
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err = cn_printf(cn, "%d", cred->uid);
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break;
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/* gid */
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case 'g':
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err = cn_printf(cn, "%d", cred->gid);
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break;
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/* signal that caused the coredump */
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case 's':
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err = cn_printf(cn, "%ld", signr);
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break;
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/* UNIX time of coredump */
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case 't': {
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struct timeval tv;
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do_gettimeofday(&tv);
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err = cn_printf(cn, "%lu", tv.tv_sec);
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break;
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}
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/* hostname */
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case 'h': {
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char *namestart = cn->corename + cn->used;
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down_read(&uts_sem);
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err = cn_printf(cn, "%s",
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utsname()->nodename);
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up_read(&uts_sem);
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cn_escape(namestart);
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break;
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}
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/* executable */
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case 'e': {
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char *commstart = cn->corename + cn->used;
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err = cn_printf(cn, "%s", current->comm);
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cn_escape(commstart);
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break;
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}
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case 'E':
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err = cn_print_exe_file(cn);
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break;
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/* core limit size */
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case 'c':
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err = cn_printf(cn, "%lu",
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rlimit(RLIMIT_CORE));
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break;
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default:
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break;
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}
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++pat_ptr;
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}
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if (err)
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return err;
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}
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/* Backward compatibility with core_uses_pid:
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*
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* If core_pattern does not include a %p (as is the default)
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* and core_uses_pid is set, then .%pid will be appended to
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* the filename. Do not do this for piped commands. */
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if (!ispipe && !pid_in_pattern && core_uses_pid) {
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err = cn_printf(cn, ".%d", task_tgid_vnr(current));
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if (err)
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return err;
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}
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out:
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return ispipe;
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}
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static int zap_process(struct task_struct *start, int exit_code)
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{
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struct task_struct *t;
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int nr = 0;
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start->signal->flags = SIGNAL_GROUP_EXIT;
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start->signal->group_exit_code = exit_code;
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start->signal->group_stop_count = 0;
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t = start;
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do {
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task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
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if (t != current && t->mm) {
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sigaddset(&t->pending.signal, SIGKILL);
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signal_wake_up(t, 1);
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nr++;
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}
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} while_each_thread(start, t);
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return nr;
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}
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static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
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struct core_state *core_state, int exit_code)
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{
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struct task_struct *g, *p;
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unsigned long flags;
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int nr = -EAGAIN;
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spin_lock_irq(&tsk->sighand->siglock);
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if (!signal_group_exit(tsk->signal)) {
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mm->core_state = core_state;
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nr = zap_process(tsk, exit_code);
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}
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spin_unlock_irq(&tsk->sighand->siglock);
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if (unlikely(nr < 0))
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return nr;
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if (atomic_read(&mm->mm_users) == nr + 1)
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goto done;
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/*
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* We should find and kill all tasks which use this mm, and we should
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* count them correctly into ->nr_threads. We don't take tasklist
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* lock, but this is safe wrt:
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*
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* fork:
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* None of sub-threads can fork after zap_process(leader). All
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* processes which were created before this point should be
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* visible to zap_threads() because copy_process() adds the new
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* process to the tail of init_task.tasks list, and lock/unlock
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* of ->siglock provides a memory barrier.
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*
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* do_exit:
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* The caller holds mm->mmap_sem. This means that the task which
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* uses this mm can't pass exit_mm(), so it can't exit or clear
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* its ->mm.
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*
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* de_thread:
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* It does list_replace_rcu(&leader->tasks, ¤t->tasks),
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* we must see either old or new leader, this does not matter.
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* However, it can change p->sighand, so lock_task_sighand(p)
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* must be used. Since p->mm != NULL and we hold ->mmap_sem
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* it can't fail.
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*
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* Note also that "g" can be the old leader with ->mm == NULL
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* and already unhashed and thus removed from ->thread_group.
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* This is OK, __unhash_process()->list_del_rcu() does not
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* clear the ->next pointer, we will find the new leader via
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* next_thread().
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*/
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rcu_read_lock();
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for_each_process(g) {
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if (g == tsk->group_leader)
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continue;
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if (g->flags & PF_KTHREAD)
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continue;
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p = g;
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do {
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if (p->mm) {
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if (unlikely(p->mm == mm)) {
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lock_task_sighand(p, &flags);
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nr += zap_process(p, exit_code);
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unlock_task_sighand(p, &flags);
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}
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break;
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}
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} while_each_thread(g, p);
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}
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rcu_read_unlock();
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done:
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atomic_set(&core_state->nr_threads, nr);
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return nr;
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}
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static int coredump_wait(int exit_code, struct core_state *core_state)
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{
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struct task_struct *tsk = current;
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struct mm_struct *mm = tsk->mm;
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int core_waiters = -EBUSY;
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init_completion(&core_state->startup);
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core_state->dumper.task = tsk;
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core_state->dumper.next = NULL;
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down_write(&mm->mmap_sem);
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if (!mm->core_state)
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core_waiters = zap_threads(tsk, mm, core_state, exit_code);
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up_write(&mm->mmap_sem);
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if (core_waiters > 0) {
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struct core_thread *ptr;
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wait_for_completion(&core_state->startup);
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/*
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* Wait for all the threads to become inactive, so that
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* all the thread context (extended register state, like
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* fpu etc) gets copied to the memory.
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*/
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ptr = core_state->dumper.next;
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while (ptr != NULL) {
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wait_task_inactive(ptr->task, 0);
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ptr = ptr->next;
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}
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}
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return core_waiters;
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}
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static void coredump_finish(struct mm_struct *mm)
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{
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struct core_thread *curr, *next;
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struct task_struct *task;
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next = mm->core_state->dumper.next;
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while ((curr = next) != NULL) {
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next = curr->next;
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task = curr->task;
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/*
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* see exit_mm(), curr->task must not see
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* ->task == NULL before we read ->next.
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*/
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smp_mb();
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curr->task = NULL;
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wake_up_process(task);
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}
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mm->core_state = NULL;
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}
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static void wait_for_dump_helpers(struct file *file)
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{
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struct pipe_inode_info *pipe;
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pipe = file->f_path.dentry->d_inode->i_pipe;
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pipe_lock(pipe);
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pipe->readers++;
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pipe->writers--;
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while ((pipe->readers > 1) && (!signal_pending(current))) {
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wake_up_interruptible_sync(&pipe->wait);
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kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
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pipe_wait(pipe);
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}
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pipe->readers--;
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pipe->writers++;
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pipe_unlock(pipe);
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}
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/*
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* umh_pipe_setup
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* helper function to customize the process used
|
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* to collect the core in userspace. Specifically
|
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* it sets up a pipe and installs it as fd 0 (stdin)
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* for the process. Returns 0 on success, or
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* PTR_ERR on failure.
|
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* Note that it also sets the core limit to 1. This
|
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* is a special value that we use to trap recursive
|
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* core dumps
|
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*/
|
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static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
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{
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struct file *files[2];
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struct coredump_params *cp = (struct coredump_params *)info->data;
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int err = create_pipe_files(files, 0);
|
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if (err)
|
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return err;
|
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|
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cp->file = files[1];
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replace_fd(0, files[0], 0);
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/* and disallow core files too */
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current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1};
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return 0;
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}
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void do_coredump(long signr, int exit_code, struct pt_regs *regs)
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{
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struct core_state core_state;
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struct core_name cn;
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struct mm_struct *mm = current->mm;
|
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struct linux_binfmt * binfmt;
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const struct cred *old_cred;
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struct cred *cred;
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int retval = 0;
|
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int flag = 0;
|
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int ispipe;
|
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struct files_struct *displaced;
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bool need_nonrelative = false;
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static atomic_t core_dump_count = ATOMIC_INIT(0);
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struct coredump_params cprm = {
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.signr = signr,
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.regs = regs,
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.limit = rlimit(RLIMIT_CORE),
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/*
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||||
* 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;
|
||||
}
|
||||
|
||||
/* get us an unshared descriptor table; almost always a no-op */
|
||||
retval = unshare_files(&displaced);
|
||||
if (retval)
|
||||
goto close_fail;
|
||||
if (displaced)
|
||||
put_files_struct(displaced);
|
||||
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);
|
||||
645
fs/exec.c
645
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);
|
||||
|
||||
|
|
@ -1603,353 +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
|
||||
|
|
@ -1991,7 +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;
|
||||
|
||||
|
|
@ -2003,288 +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 coredump_params *cp = (struct coredump_params *)info->data;
|
||||
int err = create_pipe_files(files, 0);
|
||||
if (err)
|
||||
return err;
|
||||
|
||||
cp->file = files[1];
|
||||
|
||||
replace_fd(0, files[0], 0);
|
||||
/* 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;
|
||||
struct files_struct *displaced;
|
||||
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;
|
||||
}
|
||||
|
||||
/* get us an unshared descriptor table; almost always a no-op */
|
||||
retval = unshare_files(&displaced);
|
||||
if (retval)
|
||||
goto close_fail;
|
||||
if (displaced)
|
||||
put_files_struct(displaced);
|
||||
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);
|
||||
|
|
|
|||
|
|
@ -405,6 +405,7 @@ static inline void arch_pick_mmap_layout(struct mm_struct *mm) {}
|
|||
|
||||
extern void set_dumpable(struct mm_struct *mm, int value);
|
||||
extern int get_dumpable(struct mm_struct *mm);
|
||||
extern int __get_dumpable(unsigned long mm_flags);
|
||||
|
||||
/* get/set_dumpable() values */
|
||||
#define SUID_DUMPABLE_DISABLED 0
|
||||
|
|
|
|||
Loading…
Reference in a new issue