2012-09-27 03:52:08 +02:00
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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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2012-10-05 02:15:24 +02:00
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#include <linux/coredump.h>
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2012-09-27 03:52:08 +02:00
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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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unsigned int core_pipe_limit;
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2013-07-04 00:08:22 +02:00
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char core_pattern[CORENAME_MAX_SIZE] = "core";
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static int core_name_size = CORENAME_MAX_SIZE;
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2012-09-27 03:52:08 +02:00
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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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/* The maximal length of core_pattern is also specified in sysctl.c */
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2013-07-04 00:08:22 +02:00
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static int expand_corename(struct core_name *cn, int size)
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2012-09-27 03:52:08 +02:00
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{
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2013-07-04 00:08:16 +02:00
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char *corename = krealloc(cn->corename, size, GFP_KERNEL);
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2012-09-27 03:52:08 +02:00
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2013-07-04 00:08:16 +02:00
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if (!corename)
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2012-09-27 03:52:08 +02:00
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return -ENOMEM;
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2013-07-04 00:08:22 +02:00
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if (size > core_name_size) /* racy but harmless */
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core_name_size = size;
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cn->size = ksize(corename);
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2013-07-04 00:08:16 +02:00
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cn->corename = corename;
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2012-09-27 03:52:08 +02:00
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return 0;
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}
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2015-06-26 00:03:53 +02:00
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static __printf(2, 0) int cn_vprintf(struct core_name *cn, const char *fmt,
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va_list arg)
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2012-09-27 03:52:08 +02:00
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{
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2013-07-04 00:08:19 +02:00
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int free, need;
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2014-04-19 19:15:07 +02:00
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va_list arg_copy;
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2012-09-27 03:52:08 +02:00
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2013-07-04 00:08:19 +02:00
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again:
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free = cn->size - cn->used;
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2014-04-19 19:15:07 +02:00
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va_copy(arg_copy, arg);
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need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy);
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va_end(arg_copy);
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2013-07-04 00:08:19 +02:00
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if (need < free) {
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cn->used += need;
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return 0;
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}
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2012-09-27 03:52:08 +02:00
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2013-07-04 00:08:22 +02:00
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if (!expand_corename(cn, cn->size + need - free + 1))
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2013-07-04 00:08:19 +02:00
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goto again;
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2012-09-27 03:52:08 +02:00
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2013-07-04 00:08:19 +02:00
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return -ENOMEM;
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2012-09-27 03:52:08 +02:00
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}
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2015-06-26 00:03:53 +02:00
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static __printf(2, 3) int cn_printf(struct core_name *cn, const char *fmt, ...)
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2013-07-04 00:08:17 +02:00
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{
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va_list arg;
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int ret;
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va_start(arg, fmt);
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ret = cn_vprintf(cn, fmt, arg);
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va_end(arg);
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return ret;
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}
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2015-06-26 00:03:53 +02:00
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static __printf(2, 3)
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int cn_esc_printf(struct core_name *cn, const char *fmt, ...)
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2012-09-27 03:52:08 +02:00
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{
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2013-07-04 00:08:20 +02:00
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int cur = cn->used;
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va_list arg;
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int ret;
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va_start(arg, fmt);
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ret = cn_vprintf(cn, fmt, arg);
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va_end(arg);
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for (; cur < cn->used; ++cur) {
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if (cn->corename[cur] == '/')
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cn->corename[cur] = '!';
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}
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return ret;
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2012-09-27 03:52:08 +02:00
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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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2013-07-04 00:08:20 +02:00
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if (!exe_file)
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return cn_esc_printf(cn, "%s (path unknown)", current->comm);
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2012-09-27 03:52:08 +02:00
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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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2015-06-19 10:29:13 +02:00
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path = file_path(exe_file, pathbuf, PATH_MAX);
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2012-09-27 03:52:08 +02:00
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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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2013-07-04 00:08:20 +02:00
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ret = cn_esc_printf(cn, "%s", path);
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2012-09-27 03:52:08 +02:00
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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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2012-10-05 02:15:25 +02:00
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static int format_corename(struct core_name *cn, struct coredump_params *cprm)
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2012-09-27 03:52:08 +02:00
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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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2013-07-04 00:08:16 +02:00
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cn->used = 0;
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2013-07-04 00:08:22 +02:00
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cn->corename = NULL;
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if (expand_corename(cn, core_name_size))
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2012-09-27 03:52:08 +02:00
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return -ENOMEM;
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2013-07-04 00:08:23 +02:00
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cn->corename[0] = '\0';
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if (ispipe)
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++pat_ptr;
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2012-09-27 03:52:08 +02:00
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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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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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2013-09-11 23:24:32 +02:00
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/* global pid */
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case 'P':
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err = cn_printf(cn, "%d",
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task_tgid_nr(current));
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break;
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2014-10-14 00:53:35 +02:00
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case 'i':
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err = cn_printf(cn, "%d",
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task_pid_vnr(current));
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break;
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case 'I':
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err = cn_printf(cn, "%d",
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task_pid_nr(current));
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break;
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2012-09-27 03:52:08 +02:00
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/* uid */
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case 'u':
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coredump: use from_kuid/kgid when formatting corename
When adding __printf attribute to cn_printf, gcc reports some issues:
fs/coredump.c:213:5: warning: format '%d' expects argument of type
'int', but argument 3 has type 'kuid_t' [-Wformat=]
err = cn_printf(cn, "%d", cred->uid);
^
fs/coredump.c:217:5: warning: format '%d' expects argument of type
'int', but argument 3 has type 'kgid_t' [-Wformat=]
err = cn_printf(cn, "%d", cred->gid);
^
These warnings come from the fact that the value of uid/gid needs to be
extracted from the kuid_t/kgid_t structure before being used as an
integer. More precisely, cred->uid and cred->gid need to be converted to
either user-namespace uid/gid or to init_user_ns uid/gid.
Use init_user_ns in order not to break existing ABI, and document this in
Documentation/sysctl/kernel.txt.
While at it, format uid and gid values with %u instead of %d because
uid_t/__kernel_uid32_t and gid_t/__kernel_gid32_t are unsigned int.
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-26 00:03:51 +02:00
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err = cn_printf(cn, "%u",
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from_kuid(&init_user_ns,
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cred->uid));
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2012-09-27 03:52:08 +02:00
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break;
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/* gid */
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case 'g':
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coredump: use from_kuid/kgid when formatting corename
When adding __printf attribute to cn_printf, gcc reports some issues:
fs/coredump.c:213:5: warning: format '%d' expects argument of type
'int', but argument 3 has type 'kuid_t' [-Wformat=]
err = cn_printf(cn, "%d", cred->uid);
^
fs/coredump.c:217:5: warning: format '%d' expects argument of type
'int', but argument 3 has type 'kgid_t' [-Wformat=]
err = cn_printf(cn, "%d", cred->gid);
^
These warnings come from the fact that the value of uid/gid needs to be
extracted from the kuid_t/kgid_t structure before being used as an
integer. More precisely, cred->uid and cred->gid need to be converted to
either user-namespace uid/gid or to init_user_ns uid/gid.
Use init_user_ns in order not to break existing ABI, and document this in
Documentation/sysctl/kernel.txt.
While at it, format uid and gid values with %u instead of %d because
uid_t/__kernel_uid32_t and gid_t/__kernel_gid32_t are unsigned int.
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-26 00:03:51 +02:00
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err = cn_printf(cn, "%u",
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from_kgid(&init_user_ns,
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cred->gid));
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2012-09-27 03:52:08 +02:00
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break;
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2012-10-05 02:15:25 +02:00
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case 'd':
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err = cn_printf(cn, "%d",
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__get_dumpable(cprm->mm_flags));
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break;
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2012-09-27 03:52:08 +02:00
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/* signal that caused the coredump */
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case 's':
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2015-06-26 00:03:53 +02:00
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err = cn_printf(cn, "%d",
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cprm->siginfo->si_signo);
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2012-09-27 03:52:08 +02:00
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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 */
|
2013-07-04 00:08:20 +02:00
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case 'h':
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2012-09-27 03:52:08 +02:00
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down_read(&uts_sem);
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2013-07-04 00:08:20 +02:00
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err = cn_esc_printf(cn, "%s",
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2012-09-27 03:52:08 +02:00
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utsname()->nodename);
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up_read(&uts_sem);
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break;
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/* executable */
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2013-07-04 00:08:20 +02:00
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case 'e':
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err = cn_esc_printf(cn, "%s", current->comm);
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2012-09-27 03:52:08 +02:00
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break;
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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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2013-07-04 00:08:23 +02:00
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out:
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2012-09-27 03:52:08 +02:00
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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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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->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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|
|
2013-05-01 00:28:10 +02:00
|
|
|
static int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
|
|
|
|
struct core_state *core_state, int exit_code)
|
2012-09-27 03:52:08 +02:00
|
|
|
{
|
|
|
|
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);
|
2013-05-01 00:28:12 +02:00
|
|
|
tsk->signal->group_exit_task = tsk;
|
2013-05-01 00:28:10 +02:00
|
|
|
/* ignore all signals except SIGKILL, see prepare_signal() */
|
2013-05-01 00:28:12 +02:00
|
|
|
tsk->signal->flags = SIGNAL_GROUP_COREDUMP;
|
2013-05-01 00:28:10 +02:00
|
|
|
clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
|
2012-09-27 03:52:08 +02:00
|
|
|
}
|
|
|
|
spin_unlock_irq(&tsk->sighand->siglock);
|
|
|
|
if (unlikely(nr < 0))
|
|
|
|
return nr;
|
|
|
|
|
2014-07-23 22:59:59 +02:00
|
|
|
tsk->flags |= PF_DUMPCORE;
|
2012-09-27 03:52:08 +02:00
|
|
|
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);
|
2013-05-01 00:28:12 +02:00
|
|
|
p->signal->flags = SIGNAL_GROUP_EXIT;
|
2012-09-27 03:52:08 +02:00
|
|
|
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;
|
|
|
|
}
|
|
|
|
|
2013-05-01 00:28:13 +02:00
|
|
|
static void coredump_finish(struct mm_struct *mm, bool core_dumped)
|
2012-09-27 03:52:08 +02:00
|
|
|
{
|
|
|
|
struct core_thread *curr, *next;
|
|
|
|
struct task_struct *task;
|
|
|
|
|
2013-05-01 00:28:12 +02:00
|
|
|
spin_lock_irq(¤t->sighand->siglock);
|
2013-05-01 00:28:13 +02:00
|
|
|
if (core_dumped && !__fatal_signal_pending(current))
|
|
|
|
current->signal->group_exit_code |= 0x80;
|
2013-05-01 00:28:12 +02:00
|
|
|
current->signal->group_exit_task = NULL;
|
|
|
|
current->signal->flags = SIGNAL_GROUP_EXIT;
|
|
|
|
spin_unlock_irq(¤t->sighand->siglock);
|
|
|
|
|
2012-09-27 03:52:08 +02:00
|
|
|
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;
|
|
|
|
}
|
|
|
|
|
2013-05-01 00:28:15 +02:00
|
|
|
static bool dump_interrupted(void)
|
|
|
|
{
|
|
|
|
/*
|
|
|
|
* SIGKILL or freezing() interrupt the coredumping. Perhaps we
|
|
|
|
* can do try_to_freeze() and check __fatal_signal_pending(),
|
|
|
|
* but then we need to teach dump_write() to restart and clear
|
|
|
|
* TIF_SIGPENDING.
|
|
|
|
*/
|
|
|
|
return signal_pending(current);
|
|
|
|
}
|
|
|
|
|
2012-09-27 03:52:08 +02:00
|
|
|
static void wait_for_dump_helpers(struct file *file)
|
|
|
|
{
|
2013-03-21 16:16:56 +01:00
|
|
|
struct pipe_inode_info *pipe = file->private_data;
|
2012-09-27 03:52:08 +02:00
|
|
|
|
|
|
|
pipe_lock(pipe);
|
|
|
|
pipe->readers++;
|
|
|
|
pipe->writers--;
|
2013-05-01 00:28:17 +02:00
|
|
|
wake_up_interruptible_sync(&pipe->wait);
|
|
|
|
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
|
|
|
|
pipe_unlock(pipe);
|
2012-09-27 03:52:08 +02:00
|
|
|
|
2013-05-01 00:28:17 +02:00
|
|
|
/*
|
|
|
|
* We actually want wait_event_freezable() but then we need
|
|
|
|
* to clear TIF_SIGPENDING and improve dump_interrupted().
|
|
|
|
*/
|
|
|
|
wait_event_interruptible(pipe->wait, pipe->readers == 1);
|
2012-09-27 03:52:08 +02:00
|
|
|
|
2013-05-01 00:28:17 +02:00
|
|
|
pipe_lock(pipe);
|
2012-09-27 03:52:08 +02:00
|
|
|
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];
|
|
|
|
|
2012-10-16 19:30:07 +02:00
|
|
|
err = replace_fd(0, files[0], 0);
|
|
|
|
fput(files[0]);
|
2012-09-27 03:52:08 +02:00
|
|
|
/* and disallow core files too */
|
|
|
|
current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1};
|
|
|
|
|
2012-10-16 19:30:07 +02:00
|
|
|
return err;
|
2012-09-27 03:52:08 +02:00
|
|
|
}
|
|
|
|
|
2013-10-13 23:57:29 +02:00
|
|
|
void do_coredump(const siginfo_t *siginfo)
|
2012-09-27 03:52:08 +02:00
|
|
|
{
|
|
|
|
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 ispipe;
|
|
|
|
struct files_struct *displaced;
|
fs: if a coredump already exists, unlink and recreate with O_EXCL
It was possible for an attacking user to trick root (or another user) into
writing his coredumps into an attacker-readable, pre-existing file using
rename() or link(), causing the disclosure of secret data from the victim
process' virtual memory. Depending on the configuration, it was also
possible to trick root into overwriting system files with coredumps. Fix
that issue by never writing coredumps into existing files.
Requirements for the attack:
- The attack only applies if the victim's process has a nonzero
RLIMIT_CORE and is dumpable.
- The attacker can trick the victim into coredumping into an
attacker-writable directory D, either because the core_pattern is
relative and the victim's cwd is attacker-writable or because an
absolute core_pattern pointing to a world-writable directory is used.
- The attacker has one of these:
A: on a system with protected_hardlinks=0:
execute access to a folder containing a victim-owned,
attacker-readable file on the same partition as D, and the
victim-owned file will be deleted before the main part of the attack
takes place. (In practice, there are lots of files that fulfill
this condition, e.g. entries in Debian's /var/lib/dpkg/info/.)
This does not apply to most Linux systems because most distros set
protected_hardlinks=1.
B: on a system with protected_hardlinks=1:
execute access to a folder containing a victim-owned,
attacker-readable and attacker-writable file on the same partition
as D, and the victim-owned file will be deleted before the main part
of the attack takes place.
(This seems to be uncommon.)
C: on any system, independent of protected_hardlinks:
write access to a non-sticky folder containing a victim-owned,
attacker-readable file on the same partition as D
(This seems to be uncommon.)
The basic idea is that the attacker moves the victim-owned file to where
he expects the victim process to dump its core. The victim process dumps
its core into the existing file, and the attacker reads the coredump from
it.
If the attacker can't move the file because he does not have write access
to the containing directory, he can instead link the file to a directory
he controls, then wait for the original link to the file to be deleted
(because the kernel checks that the link count of the corefile is 1).
A less reliable variant that requires D to be non-sticky works with link()
and does not require deletion of the original link: link() the file into
D, but then unlink() it directly before the kernel performs the link count
check.
On systems with protected_hardlinks=0, this variant allows an attacker to
not only gain information from coredumps, but also clobber existing,
victim-writable files with coredumps. (This could theoretically lead to a
privilege escalation.)
Signed-off-by: Jann Horn <jann@thejh.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10 00:38:28 +02:00
|
|
|
/* require nonrelative corefile path and be extra careful */
|
|
|
|
bool need_suid_safe = false;
|
2013-05-01 00:28:13 +02:00
|
|
|
bool core_dumped = false;
|
2012-09-27 03:52:08 +02:00
|
|
|
static atomic_t core_dump_count = ATOMIC_INIT(0);
|
|
|
|
struct coredump_params cprm = {
|
2012-10-05 02:15:29 +02:00
|
|
|
.siginfo = siginfo,
|
2012-11-05 19:11:26 +01:00
|
|
|
.regs = signal_pt_regs(),
|
2012-09-27 03:52:08 +02:00
|
|
|
.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,
|
|
|
|
};
|
|
|
|
|
2012-10-05 02:15:29 +02:00
|
|
|
audit_core_dumps(siginfo->si_signo);
|
2012-09-27 03:52:08 +02:00
|
|
|
|
|
|
|
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).
|
|
|
|
*/
|
2013-02-28 02:03:15 +01:00
|
|
|
if (__get_dumpable(cprm.mm_flags) == SUID_DUMP_ROOT) {
|
2012-09-27 03:52:08 +02:00
|
|
|
/* Setuid core dump mode */
|
|
|
|
cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */
|
fs: if a coredump already exists, unlink and recreate with O_EXCL
It was possible for an attacking user to trick root (or another user) into
writing his coredumps into an attacker-readable, pre-existing file using
rename() or link(), causing the disclosure of secret data from the victim
process' virtual memory. Depending on the configuration, it was also
possible to trick root into overwriting system files with coredumps. Fix
that issue by never writing coredumps into existing files.
Requirements for the attack:
- The attack only applies if the victim's process has a nonzero
RLIMIT_CORE and is dumpable.
- The attacker can trick the victim into coredumping into an
attacker-writable directory D, either because the core_pattern is
relative and the victim's cwd is attacker-writable or because an
absolute core_pattern pointing to a world-writable directory is used.
- The attacker has one of these:
A: on a system with protected_hardlinks=0:
execute access to a folder containing a victim-owned,
attacker-readable file on the same partition as D, and the
victim-owned file will be deleted before the main part of the attack
takes place. (In practice, there are lots of files that fulfill
this condition, e.g. entries in Debian's /var/lib/dpkg/info/.)
This does not apply to most Linux systems because most distros set
protected_hardlinks=1.
B: on a system with protected_hardlinks=1:
execute access to a folder containing a victim-owned,
attacker-readable and attacker-writable file on the same partition
as D, and the victim-owned file will be deleted before the main part
of the attack takes place.
(This seems to be uncommon.)
C: on any system, independent of protected_hardlinks:
write access to a non-sticky folder containing a victim-owned,
attacker-readable file on the same partition as D
(This seems to be uncommon.)
The basic idea is that the attacker moves the victim-owned file to where
he expects the victim process to dump its core. The victim process dumps
its core into the existing file, and the attacker reads the coredump from
it.
If the attacker can't move the file because he does not have write access
to the containing directory, he can instead link the file to a directory
he controls, then wait for the original link to the file to be deleted
(because the kernel checks that the link count of the corefile is 1).
A less reliable variant that requires D to be non-sticky works with link()
and does not require deletion of the original link: link() the file into
D, but then unlink() it directly before the kernel performs the link count
check.
On systems with protected_hardlinks=0, this variant allows an attacker to
not only gain information from coredumps, but also clobber existing,
victim-writable files with coredumps. (This could theoretically lead to a
privilege escalation.)
Signed-off-by: Jann Horn <jann@thejh.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10 00:38:28 +02:00
|
|
|
need_suid_safe = true;
|
2012-09-27 03:52:08 +02:00
|
|
|
}
|
|
|
|
|
2012-10-05 02:15:29 +02:00
|
|
|
retval = coredump_wait(siginfo->si_signo, &core_state);
|
2012-09-27 03:52:08 +02:00
|
|
|
if (retval < 0)
|
|
|
|
goto fail_creds;
|
|
|
|
|
|
|
|
old_cred = override_creds(cred);
|
|
|
|
|
2012-10-05 02:15:25 +02:00
|
|
|
ispipe = format_corename(&cn, &cprm);
|
2012-09-27 03:52:08 +02:00
|
|
|
|
2013-05-01 00:28:06 +02:00
|
|
|
if (ispipe) {
|
2012-09-27 03:52:08 +02:00
|
|
|
int dump_count;
|
|
|
|
char **helper_argv;
|
2013-05-01 00:28:07 +02:00
|
|
|
struct subprocess_info *sub_info;
|
2012-09-27 03:52:08 +02:00
|
|
|
|
|
|
|
if (ispipe < 0) {
|
|
|
|
printk(KERN_WARNING "format_corename failed\n");
|
|
|
|
printk(KERN_WARNING "Aborting core\n");
|
2013-07-04 00:08:16 +02:00
|
|
|
goto fail_unlock;
|
2012-09-27 03:52:08 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
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
|
2015-02-05 14:35:05 +01:00
|
|
|
* cprm.limit of 1 here as a special value, this is a
|
2012-09-27 03:52:08 +02:00
|
|
|
* 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;
|
|
|
|
}
|
|
|
|
|
2013-07-04 00:08:23 +02:00
|
|
|
helper_argv = argv_split(GFP_KERNEL, cn.corename, NULL);
|
2012-09-27 03:52:08 +02:00
|
|
|
if (!helper_argv) {
|
|
|
|
printk(KERN_WARNING "%s failed to allocate memory\n",
|
|
|
|
__func__);
|
|
|
|
goto fail_dropcount;
|
|
|
|
}
|
|
|
|
|
2013-05-01 00:28:07 +02:00
|
|
|
retval = -ENOMEM;
|
|
|
|
sub_info = call_usermodehelper_setup(helper_argv[0],
|
|
|
|
helper_argv, NULL, GFP_KERNEL,
|
|
|
|
umh_pipe_setup, NULL, &cprm);
|
|
|
|
if (sub_info)
|
|
|
|
retval = call_usermodehelper_exec(sub_info,
|
|
|
|
UMH_WAIT_EXEC);
|
|
|
|
|
2012-09-27 03:52:08 +02:00
|
|
|
argv_free(helper_argv);
|
|
|
|
if (retval) {
|
2013-07-04 00:08:23 +02:00
|
|
|
printk(KERN_INFO "Core dump to |%s pipe failed\n",
|
2012-09-27 03:52:08 +02:00
|
|
|
cn.corename);
|
|
|
|
goto close_fail;
|
2013-05-01 00:28:06 +02:00
|
|
|
}
|
2012-09-27 03:52:08 +02:00
|
|
|
} else {
|
|
|
|
struct inode *inode;
|
|
|
|
|
|
|
|
if (cprm.limit < binfmt->min_coredump)
|
|
|
|
goto fail_unlock;
|
|
|
|
|
fs: if a coredump already exists, unlink and recreate with O_EXCL
It was possible for an attacking user to trick root (or another user) into
writing his coredumps into an attacker-readable, pre-existing file using
rename() or link(), causing the disclosure of secret data from the victim
process' virtual memory. Depending on the configuration, it was also
possible to trick root into overwriting system files with coredumps. Fix
that issue by never writing coredumps into existing files.
Requirements for the attack:
- The attack only applies if the victim's process has a nonzero
RLIMIT_CORE and is dumpable.
- The attacker can trick the victim into coredumping into an
attacker-writable directory D, either because the core_pattern is
relative and the victim's cwd is attacker-writable or because an
absolute core_pattern pointing to a world-writable directory is used.
- The attacker has one of these:
A: on a system with protected_hardlinks=0:
execute access to a folder containing a victim-owned,
attacker-readable file on the same partition as D, and the
victim-owned file will be deleted before the main part of the attack
takes place. (In practice, there are lots of files that fulfill
this condition, e.g. entries in Debian's /var/lib/dpkg/info/.)
This does not apply to most Linux systems because most distros set
protected_hardlinks=1.
B: on a system with protected_hardlinks=1:
execute access to a folder containing a victim-owned,
attacker-readable and attacker-writable file on the same partition
as D, and the victim-owned file will be deleted before the main part
of the attack takes place.
(This seems to be uncommon.)
C: on any system, independent of protected_hardlinks:
write access to a non-sticky folder containing a victim-owned,
attacker-readable file on the same partition as D
(This seems to be uncommon.)
The basic idea is that the attacker moves the victim-owned file to where
he expects the victim process to dump its core. The victim process dumps
its core into the existing file, and the attacker reads the coredump from
it.
If the attacker can't move the file because he does not have write access
to the containing directory, he can instead link the file to a directory
he controls, then wait for the original link to the file to be deleted
(because the kernel checks that the link count of the corefile is 1).
A less reliable variant that requires D to be non-sticky works with link()
and does not require deletion of the original link: link() the file into
D, but then unlink() it directly before the kernel performs the link count
check.
On systems with protected_hardlinks=0, this variant allows an attacker to
not only gain information from coredumps, but also clobber existing,
victim-writable files with coredumps. (This could theoretically lead to a
privilege escalation.)
Signed-off-by: Jann Horn <jann@thejh.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10 00:38:28 +02:00
|
|
|
if (need_suid_safe && cn.corename[0] != '/') {
|
2012-09-27 03:52:08 +02:00
|
|
|
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;
|
|
|
|
}
|
|
|
|
|
fs: if a coredump already exists, unlink and recreate with O_EXCL
It was possible for an attacking user to trick root (or another user) into
writing his coredumps into an attacker-readable, pre-existing file using
rename() or link(), causing the disclosure of secret data from the victim
process' virtual memory. Depending on the configuration, it was also
possible to trick root into overwriting system files with coredumps. Fix
that issue by never writing coredumps into existing files.
Requirements for the attack:
- The attack only applies if the victim's process has a nonzero
RLIMIT_CORE and is dumpable.
- The attacker can trick the victim into coredumping into an
attacker-writable directory D, either because the core_pattern is
relative and the victim's cwd is attacker-writable or because an
absolute core_pattern pointing to a world-writable directory is used.
- The attacker has one of these:
A: on a system with protected_hardlinks=0:
execute access to a folder containing a victim-owned,
attacker-readable file on the same partition as D, and the
victim-owned file will be deleted before the main part of the attack
takes place. (In practice, there are lots of files that fulfill
this condition, e.g. entries in Debian's /var/lib/dpkg/info/.)
This does not apply to most Linux systems because most distros set
protected_hardlinks=1.
B: on a system with protected_hardlinks=1:
execute access to a folder containing a victim-owned,
attacker-readable and attacker-writable file on the same partition
as D, and the victim-owned file will be deleted before the main part
of the attack takes place.
(This seems to be uncommon.)
C: on any system, independent of protected_hardlinks:
write access to a non-sticky folder containing a victim-owned,
attacker-readable file on the same partition as D
(This seems to be uncommon.)
The basic idea is that the attacker moves the victim-owned file to where
he expects the victim process to dump its core. The victim process dumps
its core into the existing file, and the attacker reads the coredump from
it.
If the attacker can't move the file because he does not have write access
to the containing directory, he can instead link the file to a directory
he controls, then wait for the original link to the file to be deleted
(because the kernel checks that the link count of the corefile is 1).
A less reliable variant that requires D to be non-sticky works with link()
and does not require deletion of the original link: link() the file into
D, but then unlink() it directly before the kernel performs the link count
check.
On systems with protected_hardlinks=0, this variant allows an attacker to
not only gain information from coredumps, but also clobber existing,
victim-writable files with coredumps. (This could theoretically lead to a
privilege escalation.)
Signed-off-by: Jann Horn <jann@thejh.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10 00:38:28 +02:00
|
|
|
/*
|
|
|
|
* Unlink the file if it exists unless this is a SUID
|
|
|
|
* binary - in that case, we're running around with root
|
|
|
|
* privs and don't want to unlink another user's coredump.
|
|
|
|
*/
|
|
|
|
if (!need_suid_safe) {
|
|
|
|
mm_segment_t old_fs;
|
|
|
|
|
|
|
|
old_fs = get_fs();
|
|
|
|
set_fs(KERNEL_DS);
|
|
|
|
/*
|
|
|
|
* If it doesn't exist, that's fine. If there's some
|
|
|
|
* other problem, we'll catch it at the filp_open().
|
|
|
|
*/
|
|
|
|
(void) sys_unlink((const char __user *)cn.corename);
|
|
|
|
set_fs(old_fs);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* There is a race between unlinking and creating the
|
|
|
|
* file, but if that causes an EEXIST here, that's
|
|
|
|
* fine - another process raced with us while creating
|
|
|
|
* the corefile, and the other process won. To userspace,
|
|
|
|
* what matters is that at least one of the two processes
|
|
|
|
* writes its coredump successfully, not which one.
|
|
|
|
*/
|
2012-09-27 03:52:08 +02:00
|
|
|
cprm.file = filp_open(cn.corename,
|
fs: if a coredump already exists, unlink and recreate with O_EXCL
It was possible for an attacking user to trick root (or another user) into
writing his coredumps into an attacker-readable, pre-existing file using
rename() or link(), causing the disclosure of secret data from the victim
process' virtual memory. Depending on the configuration, it was also
possible to trick root into overwriting system files with coredumps. Fix
that issue by never writing coredumps into existing files.
Requirements for the attack:
- The attack only applies if the victim's process has a nonzero
RLIMIT_CORE and is dumpable.
- The attacker can trick the victim into coredumping into an
attacker-writable directory D, either because the core_pattern is
relative and the victim's cwd is attacker-writable or because an
absolute core_pattern pointing to a world-writable directory is used.
- The attacker has one of these:
A: on a system with protected_hardlinks=0:
execute access to a folder containing a victim-owned,
attacker-readable file on the same partition as D, and the
victim-owned file will be deleted before the main part of the attack
takes place. (In practice, there are lots of files that fulfill
this condition, e.g. entries in Debian's /var/lib/dpkg/info/.)
This does not apply to most Linux systems because most distros set
protected_hardlinks=1.
B: on a system with protected_hardlinks=1:
execute access to a folder containing a victim-owned,
attacker-readable and attacker-writable file on the same partition
as D, and the victim-owned file will be deleted before the main part
of the attack takes place.
(This seems to be uncommon.)
C: on any system, independent of protected_hardlinks:
write access to a non-sticky folder containing a victim-owned,
attacker-readable file on the same partition as D
(This seems to be uncommon.)
The basic idea is that the attacker moves the victim-owned file to where
he expects the victim process to dump its core. The victim process dumps
its core into the existing file, and the attacker reads the coredump from
it.
If the attacker can't move the file because he does not have write access
to the containing directory, he can instead link the file to a directory
he controls, then wait for the original link to the file to be deleted
(because the kernel checks that the link count of the corefile is 1).
A less reliable variant that requires D to be non-sticky works with link()
and does not require deletion of the original link: link() the file into
D, but then unlink() it directly before the kernel performs the link count
check.
On systems with protected_hardlinks=0, this variant allows an attacker to
not only gain information from coredumps, but also clobber existing,
victim-writable files with coredumps. (This could theoretically lead to a
privilege escalation.)
Signed-off-by: Jann Horn <jann@thejh.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10 00:38:28 +02:00
|
|
|
O_CREAT | 2 | O_NOFOLLOW |
|
|
|
|
O_LARGEFILE | O_EXCL,
|
2012-09-27 03:52:08 +02:00
|
|
|
0600);
|
|
|
|
if (IS_ERR(cprm.file))
|
|
|
|
goto fail_unlock;
|
|
|
|
|
2013-01-23 23:07:38 +01:00
|
|
|
inode = file_inode(cprm.file);
|
2012-09-27 03:52:08 +02:00
|
|
|
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;
|
2015-04-03 21:23:17 +02:00
|
|
|
if (!(cprm.file->f_mode & FMODE_CAN_WRITE))
|
2012-09-27 03:52:08 +02:00
|
|
|
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);
|
2013-05-04 20:45:54 +02:00
|
|
|
if (!dump_interrupted()) {
|
|
|
|
file_start_write(cprm.file);
|
|
|
|
core_dumped = binfmt->core_dump(&cprm);
|
|
|
|
file_end_write(cprm.file);
|
|
|
|
}
|
2012-09-27 03:52:08 +02:00
|
|
|
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);
|
2013-05-01 00:28:13 +02:00
|
|
|
coredump_finish(mm, core_dumped);
|
2012-09-27 03:52:08 +02:00
|
|
|
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.
|
|
|
|
*/
|
2013-10-05 21:32:35 +02:00
|
|
|
int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
|
|
|
|
{
|
|
|
|
struct file *file = cprm->file;
|
2013-10-08 15:11:48 +02:00
|
|
|
loff_t pos = file->f_pos;
|
|
|
|
ssize_t n;
|
2013-10-05 21:32:35 +02:00
|
|
|
if (cprm->written + nr > cprm->limit)
|
|
|
|
return 0;
|
2013-10-08 15:11:48 +02:00
|
|
|
while (nr) {
|
|
|
|
if (dump_interrupted())
|
|
|
|
return 0;
|
2013-11-16 03:58:33 +01:00
|
|
|
n = __kernel_write(file, addr, nr, &pos);
|
2013-10-08 15:11:48 +02:00
|
|
|
if (n <= 0)
|
|
|
|
return 0;
|
|
|
|
file->f_pos = pos;
|
|
|
|
cprm->written += n;
|
|
|
|
nr -= n;
|
|
|
|
}
|
2013-10-05 21:32:35 +02:00
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(dump_emit);
|
|
|
|
|
2013-10-08 15:26:08 +02:00
|
|
|
int dump_skip(struct coredump_params *cprm, size_t nr)
|
2012-09-27 03:52:08 +02:00
|
|
|
{
|
2013-10-08 15:26:08 +02:00
|
|
|
static char zeroes[PAGE_SIZE];
|
|
|
|
struct file *file = cprm->file;
|
2012-09-27 03:52:08 +02:00
|
|
|
if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
|
2013-10-08 15:26:08 +02:00
|
|
|
if (cprm->written + nr > cprm->limit)
|
|
|
|
return 0;
|
2013-05-01 00:28:15 +02:00
|
|
|
if (dump_interrupted() ||
|
2013-10-08 15:26:08 +02:00
|
|
|
file->f_op->llseek(file, nr, SEEK_CUR) < 0)
|
2012-09-27 03:52:08 +02:00
|
|
|
return 0;
|
2013-10-08 15:26:08 +02:00
|
|
|
cprm->written += nr;
|
|
|
|
return 1;
|
2012-09-27 03:52:08 +02:00
|
|
|
} else {
|
2013-10-08 15:26:08 +02:00
|
|
|
while (nr > PAGE_SIZE) {
|
|
|
|
if (!dump_emit(cprm, zeroes, PAGE_SIZE))
|
|
|
|
return 0;
|
|
|
|
nr -= PAGE_SIZE;
|
2012-09-27 03:52:08 +02:00
|
|
|
}
|
2013-10-08 15:26:08 +02:00
|
|
|
return dump_emit(cprm, zeroes, nr);
|
2012-09-27 03:52:08 +02:00
|
|
|
}
|
|
|
|
}
|
2013-10-08 15:26:08 +02:00
|
|
|
EXPORT_SYMBOL(dump_skip);
|
2013-10-08 17:05:01 +02:00
|
|
|
|
|
|
|
int dump_align(struct coredump_params *cprm, int align)
|
|
|
|
{
|
|
|
|
unsigned mod = cprm->written & (align - 1);
|
|
|
|
if (align & (align - 1))
|
2013-11-16 03:55:52 +01:00
|
|
|
return 0;
|
|
|
|
return mod ? dump_skip(cprm, align - mod) : 1;
|
2013-10-08 17:05:01 +02:00
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|
|
}
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|
|
EXPORT_SYMBOL(dump_align);
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