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3ba442d533
kernel/sysctl.c is a kitchen sink where everyone leaves their dirty dishes, this makes it very difficult to maintain. To help with this maintenance let's start by moving sysctls to places where they actually belong. The proc sysctl maintainers do not want to know what sysctl knobs you wish to add for your own piece of code, we just care about the core logic. This moves the binfmt_misc sysctl to its own file to help remove clutter from kernel/sysctl.c. Link: https://lkml.kernel.org/r/20211124231435.1445213-5-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Amir Goldstein <amir73il@gmail.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Antti Palosaari <crope@iki.fi> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Clemens Ladisch <clemens@ladisch.de> Cc: David Airlie <airlied@linux.ie> Cc: Douglas Gilbert <dgilbert@interlog.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Iurii Zaikin <yzaikin@google.com> Cc: James E.J. Bottomley <jejb@linux.ibm.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Joel Becker <jlbec@evilplan.org> Cc: John Ogness <john.ogness@linutronix.de> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Julia Lawall <julia.lawall@inria.fr> Cc: Kees Cook <keescook@chromium.org> Cc: Lukas Middendorf <kernel@tuxforce.de> Cc: Mark Fasheh <mark@fasheh.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Phillip Potter <phil@philpotter.co.uk> Cc: Qing Wang <wangqing@vivo.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Sebastian Reichel <sre@kernel.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Stephen Kitt <steve@sk2.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Xiaoming Ni <nixiaoming@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
841 lines
18 KiB
C
841 lines
18 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* binfmt_misc.c
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*
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* Copyright (C) 1997 Richard Günther
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*
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* binfmt_misc detects binaries via a magic or filename extension and invokes
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* a specified wrapper. See Documentation/admin-guide/binfmt-misc.rst for more details.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sched/mm.h>
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#include <linux/magic.h>
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#include <linux/binfmts.h>
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#include <linux/slab.h>
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#include <linux/ctype.h>
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#include <linux/string_helpers.h>
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#include <linux/file.h>
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#include <linux/pagemap.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/fs_context.h>
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#include <linux/syscalls.h>
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#include <linux/fs.h>
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#include <linux/uaccess.h>
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#include "internal.h"
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#ifdef DEBUG
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# define USE_DEBUG 1
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#else
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# define USE_DEBUG 0
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#endif
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enum {
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VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */
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};
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static LIST_HEAD(entries);
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static int enabled = 1;
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enum {Enabled, Magic};
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#define MISC_FMT_PRESERVE_ARGV0 (1 << 31)
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#define MISC_FMT_OPEN_BINARY (1 << 30)
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#define MISC_FMT_CREDENTIALS (1 << 29)
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#define MISC_FMT_OPEN_FILE (1 << 28)
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typedef struct {
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struct list_head list;
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unsigned long flags; /* type, status, etc. */
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int offset; /* offset of magic */
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int size; /* size of magic/mask */
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char *magic; /* magic or filename extension */
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char *mask; /* mask, NULL for exact match */
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const char *interpreter; /* filename of interpreter */
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char *name;
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struct dentry *dentry;
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struct file *interp_file;
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} Node;
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static DEFINE_RWLOCK(entries_lock);
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static struct file_system_type bm_fs_type;
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static struct vfsmount *bm_mnt;
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static int entry_count;
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/*
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* Max length of the register string. Determined by:
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* - 7 delimiters
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* - name: ~50 bytes
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* - type: 1 byte
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* - offset: 3 bytes (has to be smaller than BINPRM_BUF_SIZE)
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* - magic: 128 bytes (512 in escaped form)
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* - mask: 128 bytes (512 in escaped form)
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* - interp: ~50 bytes
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* - flags: 5 bytes
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* Round that up a bit, and then back off to hold the internal data
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* (like struct Node).
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*/
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#define MAX_REGISTER_LENGTH 1920
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/*
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* Check if we support the binfmt
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* if we do, return the node, else NULL
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* locking is done in load_misc_binary
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*/
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static Node *check_file(struct linux_binprm *bprm)
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{
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char *p = strrchr(bprm->interp, '.');
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struct list_head *l;
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/* Walk all the registered handlers. */
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list_for_each(l, &entries) {
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Node *e = list_entry(l, Node, list);
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char *s;
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int j;
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/* Make sure this one is currently enabled. */
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if (!test_bit(Enabled, &e->flags))
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continue;
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/* Do matching based on extension if applicable. */
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if (!test_bit(Magic, &e->flags)) {
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if (p && !strcmp(e->magic, p + 1))
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return e;
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continue;
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}
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/* Do matching based on magic & mask. */
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s = bprm->buf + e->offset;
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if (e->mask) {
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for (j = 0; j < e->size; j++)
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if ((*s++ ^ e->magic[j]) & e->mask[j])
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break;
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} else {
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for (j = 0; j < e->size; j++)
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if ((*s++ ^ e->magic[j]))
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break;
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}
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if (j == e->size)
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return e;
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}
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return NULL;
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}
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/*
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* the loader itself
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*/
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static int load_misc_binary(struct linux_binprm *bprm)
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{
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Node *fmt;
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struct file *interp_file = NULL;
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int retval;
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retval = -ENOEXEC;
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if (!enabled)
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return retval;
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/* to keep locking time low, we copy the interpreter string */
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read_lock(&entries_lock);
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fmt = check_file(bprm);
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if (fmt)
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dget(fmt->dentry);
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read_unlock(&entries_lock);
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if (!fmt)
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return retval;
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/* Need to be able to load the file after exec */
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retval = -ENOENT;
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if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
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goto ret;
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if (fmt->flags & MISC_FMT_PRESERVE_ARGV0) {
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bprm->interp_flags |= BINPRM_FLAGS_PRESERVE_ARGV0;
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} else {
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retval = remove_arg_zero(bprm);
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if (retval)
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goto ret;
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}
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if (fmt->flags & MISC_FMT_OPEN_BINARY)
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bprm->have_execfd = 1;
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/* make argv[1] be the path to the binary */
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retval = copy_string_kernel(bprm->interp, bprm);
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if (retval < 0)
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goto ret;
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bprm->argc++;
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/* add the interp as argv[0] */
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retval = copy_string_kernel(fmt->interpreter, bprm);
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if (retval < 0)
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goto ret;
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bprm->argc++;
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/* Update interp in case binfmt_script needs it. */
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retval = bprm_change_interp(fmt->interpreter, bprm);
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if (retval < 0)
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goto ret;
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if (fmt->flags & MISC_FMT_OPEN_FILE) {
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interp_file = file_clone_open(fmt->interp_file);
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if (!IS_ERR(interp_file))
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deny_write_access(interp_file);
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} else {
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interp_file = open_exec(fmt->interpreter);
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}
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retval = PTR_ERR(interp_file);
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if (IS_ERR(interp_file))
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goto ret;
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bprm->interpreter = interp_file;
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if (fmt->flags & MISC_FMT_CREDENTIALS)
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bprm->execfd_creds = 1;
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retval = 0;
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ret:
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dput(fmt->dentry);
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return retval;
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}
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/* Command parsers */
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/*
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* parses and copies one argument enclosed in del from *sp to *dp,
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* recognising the \x special.
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* returns pointer to the copied argument or NULL in case of an
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* error (and sets err) or null argument length.
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*/
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static char *scanarg(char *s, char del)
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{
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char c;
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while ((c = *s++) != del) {
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if (c == '\\' && *s == 'x') {
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s++;
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if (!isxdigit(*s++))
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return NULL;
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if (!isxdigit(*s++))
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return NULL;
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}
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}
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s[-1] ='\0';
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return s;
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}
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static char *check_special_flags(char *sfs, Node *e)
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{
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char *p = sfs;
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int cont = 1;
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/* special flags */
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while (cont) {
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switch (*p) {
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case 'P':
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pr_debug("register: flag: P (preserve argv0)\n");
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p++;
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e->flags |= MISC_FMT_PRESERVE_ARGV0;
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break;
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case 'O':
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pr_debug("register: flag: O (open binary)\n");
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p++;
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e->flags |= MISC_FMT_OPEN_BINARY;
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break;
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case 'C':
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pr_debug("register: flag: C (preserve creds)\n");
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p++;
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/* this flags also implies the
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open-binary flag */
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e->flags |= (MISC_FMT_CREDENTIALS |
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MISC_FMT_OPEN_BINARY);
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break;
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case 'F':
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pr_debug("register: flag: F: open interpreter file now\n");
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p++;
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e->flags |= MISC_FMT_OPEN_FILE;
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break;
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default:
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cont = 0;
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}
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}
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return p;
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}
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/*
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* This registers a new binary format, it recognises the syntax
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* ':name:type:offset:magic:mask:interpreter:flags'
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* where the ':' is the IFS, that can be chosen with the first char
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*/
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static Node *create_entry(const char __user *buffer, size_t count)
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{
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Node *e;
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int memsize, err;
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char *buf, *p;
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char del;
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pr_debug("register: received %zu bytes\n", count);
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/* some sanity checks */
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err = -EINVAL;
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if ((count < 11) || (count > MAX_REGISTER_LENGTH))
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goto out;
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err = -ENOMEM;
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memsize = sizeof(Node) + count + 8;
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e = kmalloc(memsize, GFP_KERNEL);
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if (!e)
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goto out;
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p = buf = (char *)e + sizeof(Node);
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memset(e, 0, sizeof(Node));
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if (copy_from_user(buf, buffer, count))
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goto efault;
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del = *p++; /* delimeter */
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pr_debug("register: delim: %#x {%c}\n", del, del);
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/* Pad the buffer with the delim to simplify parsing below. */
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memset(buf + count, del, 8);
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/* Parse the 'name' field. */
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e->name = p;
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p = strchr(p, del);
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if (!p)
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goto einval;
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*p++ = '\0';
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if (!e->name[0] ||
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!strcmp(e->name, ".") ||
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!strcmp(e->name, "..") ||
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strchr(e->name, '/'))
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goto einval;
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pr_debug("register: name: {%s}\n", e->name);
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/* Parse the 'type' field. */
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switch (*p++) {
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case 'E':
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pr_debug("register: type: E (extension)\n");
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e->flags = 1 << Enabled;
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break;
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case 'M':
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pr_debug("register: type: M (magic)\n");
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e->flags = (1 << Enabled) | (1 << Magic);
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break;
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default:
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goto einval;
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}
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if (*p++ != del)
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goto einval;
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if (test_bit(Magic, &e->flags)) {
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/* Handle the 'M' (magic) format. */
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char *s;
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/* Parse the 'offset' field. */
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s = strchr(p, del);
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if (!s)
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goto einval;
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*s = '\0';
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if (p != s) {
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int r = kstrtoint(p, 10, &e->offset);
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if (r != 0 || e->offset < 0)
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goto einval;
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}
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p = s;
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if (*p++)
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goto einval;
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pr_debug("register: offset: %#x\n", e->offset);
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/* Parse the 'magic' field. */
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e->magic = p;
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p = scanarg(p, del);
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if (!p)
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goto einval;
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if (!e->magic[0])
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goto einval;
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if (USE_DEBUG)
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print_hex_dump_bytes(
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KBUILD_MODNAME ": register: magic[raw]: ",
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DUMP_PREFIX_NONE, e->magic, p - e->magic);
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/* Parse the 'mask' field. */
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e->mask = p;
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p = scanarg(p, del);
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if (!p)
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goto einval;
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if (!e->mask[0]) {
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e->mask = NULL;
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pr_debug("register: mask[raw]: none\n");
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} else if (USE_DEBUG)
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print_hex_dump_bytes(
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KBUILD_MODNAME ": register: mask[raw]: ",
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DUMP_PREFIX_NONE, e->mask, p - e->mask);
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/*
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* Decode the magic & mask fields.
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* Note: while we might have accepted embedded NUL bytes from
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* above, the unescape helpers here will stop at the first one
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* it encounters.
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*/
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e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX);
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if (e->mask &&
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string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size)
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goto einval;
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if (e->size > BINPRM_BUF_SIZE ||
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BINPRM_BUF_SIZE - e->size < e->offset)
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goto einval;
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pr_debug("register: magic/mask length: %i\n", e->size);
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if (USE_DEBUG) {
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print_hex_dump_bytes(
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KBUILD_MODNAME ": register: magic[decoded]: ",
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DUMP_PREFIX_NONE, e->magic, e->size);
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if (e->mask) {
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int i;
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char *masked = kmalloc(e->size, GFP_KERNEL);
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print_hex_dump_bytes(
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KBUILD_MODNAME ": register: mask[decoded]: ",
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DUMP_PREFIX_NONE, e->mask, e->size);
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if (masked) {
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for (i = 0; i < e->size; ++i)
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masked[i] = e->magic[i] & e->mask[i];
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print_hex_dump_bytes(
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KBUILD_MODNAME ": register: magic[masked]: ",
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DUMP_PREFIX_NONE, masked, e->size);
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kfree(masked);
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}
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}
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}
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} else {
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/* Handle the 'E' (extension) format. */
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/* Skip the 'offset' field. */
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p = strchr(p, del);
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if (!p)
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goto einval;
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*p++ = '\0';
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/* Parse the 'magic' field. */
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e->magic = p;
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p = strchr(p, del);
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if (!p)
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goto einval;
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*p++ = '\0';
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if (!e->magic[0] || strchr(e->magic, '/'))
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goto einval;
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pr_debug("register: extension: {%s}\n", e->magic);
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/* Skip the 'mask' field. */
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p = strchr(p, del);
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if (!p)
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goto einval;
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*p++ = '\0';
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}
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/* Parse the 'interpreter' field. */
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e->interpreter = p;
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p = strchr(p, del);
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if (!p)
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goto einval;
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*p++ = '\0';
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if (!e->interpreter[0])
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goto einval;
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pr_debug("register: interpreter: {%s}\n", e->interpreter);
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/* Parse the 'flags' field. */
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p = check_special_flags(p, e);
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if (*p == '\n')
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p++;
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if (p != buf + count)
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goto einval;
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return e;
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out:
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return ERR_PTR(err);
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efault:
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kfree(e);
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return ERR_PTR(-EFAULT);
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einval:
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kfree(e);
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return ERR_PTR(-EINVAL);
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}
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/*
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* Set status of entry/binfmt_misc:
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* '1' enables, '0' disables and '-1' clears entry/binfmt_misc
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*/
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static int parse_command(const char __user *buffer, size_t count)
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{
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char s[4];
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|
if (count > 3)
|
|
return -EINVAL;
|
|
if (copy_from_user(s, buffer, count))
|
|
return -EFAULT;
|
|
if (!count)
|
|
return 0;
|
|
if (s[count - 1] == '\n')
|
|
count--;
|
|
if (count == 1 && s[0] == '0')
|
|
return 1;
|
|
if (count == 1 && s[0] == '1')
|
|
return 2;
|
|
if (count == 2 && s[0] == '-' && s[1] == '1')
|
|
return 3;
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* generic stuff */
|
|
|
|
static void entry_status(Node *e, char *page)
|
|
{
|
|
char *dp = page;
|
|
const char *status = "disabled";
|
|
|
|
if (test_bit(Enabled, &e->flags))
|
|
status = "enabled";
|
|
|
|
if (!VERBOSE_STATUS) {
|
|
sprintf(page, "%s\n", status);
|
|
return;
|
|
}
|
|
|
|
dp += sprintf(dp, "%s\ninterpreter %s\n", status, e->interpreter);
|
|
|
|
/* print the special flags */
|
|
dp += sprintf(dp, "flags: ");
|
|
if (e->flags & MISC_FMT_PRESERVE_ARGV0)
|
|
*dp++ = 'P';
|
|
if (e->flags & MISC_FMT_OPEN_BINARY)
|
|
*dp++ = 'O';
|
|
if (e->flags & MISC_FMT_CREDENTIALS)
|
|
*dp++ = 'C';
|
|
if (e->flags & MISC_FMT_OPEN_FILE)
|
|
*dp++ = 'F';
|
|
*dp++ = '\n';
|
|
|
|
if (!test_bit(Magic, &e->flags)) {
|
|
sprintf(dp, "extension .%s\n", e->magic);
|
|
} else {
|
|
dp += sprintf(dp, "offset %i\nmagic ", e->offset);
|
|
dp = bin2hex(dp, e->magic, e->size);
|
|
if (e->mask) {
|
|
dp += sprintf(dp, "\nmask ");
|
|
dp = bin2hex(dp, e->mask, e->size);
|
|
}
|
|
*dp++ = '\n';
|
|
*dp = '\0';
|
|
}
|
|
}
|
|
|
|
static struct inode *bm_get_inode(struct super_block *sb, int mode)
|
|
{
|
|
struct inode *inode = new_inode(sb);
|
|
|
|
if (inode) {
|
|
inode->i_ino = get_next_ino();
|
|
inode->i_mode = mode;
|
|
inode->i_atime = inode->i_mtime = inode->i_ctime =
|
|
current_time(inode);
|
|
}
|
|
return inode;
|
|
}
|
|
|
|
static void bm_evict_inode(struct inode *inode)
|
|
{
|
|
Node *e = inode->i_private;
|
|
|
|
if (e && e->flags & MISC_FMT_OPEN_FILE)
|
|
filp_close(e->interp_file, NULL);
|
|
|
|
clear_inode(inode);
|
|
kfree(e);
|
|
}
|
|
|
|
static void kill_node(Node *e)
|
|
{
|
|
struct dentry *dentry;
|
|
|
|
write_lock(&entries_lock);
|
|
list_del_init(&e->list);
|
|
write_unlock(&entries_lock);
|
|
|
|
dentry = e->dentry;
|
|
drop_nlink(d_inode(dentry));
|
|
d_drop(dentry);
|
|
dput(dentry);
|
|
simple_release_fs(&bm_mnt, &entry_count);
|
|
}
|
|
|
|
/* /<entry> */
|
|
|
|
static ssize_t
|
|
bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
|
|
{
|
|
Node *e = file_inode(file)->i_private;
|
|
ssize_t res;
|
|
char *page;
|
|
|
|
page = (char *) __get_free_page(GFP_KERNEL);
|
|
if (!page)
|
|
return -ENOMEM;
|
|
|
|
entry_status(e, page);
|
|
|
|
res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page));
|
|
|
|
free_page((unsigned long) page);
|
|
return res;
|
|
}
|
|
|
|
static ssize_t bm_entry_write(struct file *file, const char __user *buffer,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
struct dentry *root;
|
|
Node *e = file_inode(file)->i_private;
|
|
int res = parse_command(buffer, count);
|
|
|
|
switch (res) {
|
|
case 1:
|
|
/* Disable this handler. */
|
|
clear_bit(Enabled, &e->flags);
|
|
break;
|
|
case 2:
|
|
/* Enable this handler. */
|
|
set_bit(Enabled, &e->flags);
|
|
break;
|
|
case 3:
|
|
/* Delete this handler. */
|
|
root = file_inode(file)->i_sb->s_root;
|
|
inode_lock(d_inode(root));
|
|
|
|
if (!list_empty(&e->list))
|
|
kill_node(e);
|
|
|
|
inode_unlock(d_inode(root));
|
|
break;
|
|
default:
|
|
return res;
|
|
}
|
|
|
|
return count;
|
|
}
|
|
|
|
static const struct file_operations bm_entry_operations = {
|
|
.read = bm_entry_read,
|
|
.write = bm_entry_write,
|
|
.llseek = default_llseek,
|
|
};
|
|
|
|
/* /register */
|
|
|
|
static ssize_t bm_register_write(struct file *file, const char __user *buffer,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
Node *e;
|
|
struct inode *inode;
|
|
struct super_block *sb = file_inode(file)->i_sb;
|
|
struct dentry *root = sb->s_root, *dentry;
|
|
int err = 0;
|
|
struct file *f = NULL;
|
|
|
|
e = create_entry(buffer, count);
|
|
|
|
if (IS_ERR(e))
|
|
return PTR_ERR(e);
|
|
|
|
if (e->flags & MISC_FMT_OPEN_FILE) {
|
|
f = open_exec(e->interpreter);
|
|
if (IS_ERR(f)) {
|
|
pr_notice("register: failed to install interpreter file %s\n",
|
|
e->interpreter);
|
|
kfree(e);
|
|
return PTR_ERR(f);
|
|
}
|
|
e->interp_file = f;
|
|
}
|
|
|
|
inode_lock(d_inode(root));
|
|
dentry = lookup_one_len(e->name, root, strlen(e->name));
|
|
err = PTR_ERR(dentry);
|
|
if (IS_ERR(dentry))
|
|
goto out;
|
|
|
|
err = -EEXIST;
|
|
if (d_really_is_positive(dentry))
|
|
goto out2;
|
|
|
|
inode = bm_get_inode(sb, S_IFREG | 0644);
|
|
|
|
err = -ENOMEM;
|
|
if (!inode)
|
|
goto out2;
|
|
|
|
err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count);
|
|
if (err) {
|
|
iput(inode);
|
|
inode = NULL;
|
|
goto out2;
|
|
}
|
|
|
|
e->dentry = dget(dentry);
|
|
inode->i_private = e;
|
|
inode->i_fop = &bm_entry_operations;
|
|
|
|
d_instantiate(dentry, inode);
|
|
write_lock(&entries_lock);
|
|
list_add(&e->list, &entries);
|
|
write_unlock(&entries_lock);
|
|
|
|
err = 0;
|
|
out2:
|
|
dput(dentry);
|
|
out:
|
|
inode_unlock(d_inode(root));
|
|
|
|
if (err) {
|
|
if (f)
|
|
filp_close(f, NULL);
|
|
kfree(e);
|
|
return err;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
static const struct file_operations bm_register_operations = {
|
|
.write = bm_register_write,
|
|
.llseek = noop_llseek,
|
|
};
|
|
|
|
/* /status */
|
|
|
|
static ssize_t
|
|
bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
|
|
{
|
|
char *s = enabled ? "enabled\n" : "disabled\n";
|
|
|
|
return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s));
|
|
}
|
|
|
|
static ssize_t bm_status_write(struct file *file, const char __user *buffer,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
int res = parse_command(buffer, count);
|
|
struct dentry *root;
|
|
|
|
switch (res) {
|
|
case 1:
|
|
/* Disable all handlers. */
|
|
enabled = 0;
|
|
break;
|
|
case 2:
|
|
/* Enable all handlers. */
|
|
enabled = 1;
|
|
break;
|
|
case 3:
|
|
/* Delete all handlers. */
|
|
root = file_inode(file)->i_sb->s_root;
|
|
inode_lock(d_inode(root));
|
|
|
|
while (!list_empty(&entries))
|
|
kill_node(list_first_entry(&entries, Node, list));
|
|
|
|
inode_unlock(d_inode(root));
|
|
break;
|
|
default:
|
|
return res;
|
|
}
|
|
|
|
return count;
|
|
}
|
|
|
|
static const struct file_operations bm_status_operations = {
|
|
.read = bm_status_read,
|
|
.write = bm_status_write,
|
|
.llseek = default_llseek,
|
|
};
|
|
|
|
/* Superblock handling */
|
|
|
|
static const struct super_operations s_ops = {
|
|
.statfs = simple_statfs,
|
|
.evict_inode = bm_evict_inode,
|
|
};
|
|
|
|
static int bm_fill_super(struct super_block *sb, struct fs_context *fc)
|
|
{
|
|
int err;
|
|
static const struct tree_descr bm_files[] = {
|
|
[2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO},
|
|
[3] = {"register", &bm_register_operations, S_IWUSR},
|
|
/* last one */ {""}
|
|
};
|
|
|
|
err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files);
|
|
if (!err)
|
|
sb->s_op = &s_ops;
|
|
return err;
|
|
}
|
|
|
|
static int bm_get_tree(struct fs_context *fc)
|
|
{
|
|
return get_tree_single(fc, bm_fill_super);
|
|
}
|
|
|
|
static const struct fs_context_operations bm_context_ops = {
|
|
.get_tree = bm_get_tree,
|
|
};
|
|
|
|
static int bm_init_fs_context(struct fs_context *fc)
|
|
{
|
|
fc->ops = &bm_context_ops;
|
|
return 0;
|
|
}
|
|
|
|
static struct linux_binfmt misc_format = {
|
|
.module = THIS_MODULE,
|
|
.load_binary = load_misc_binary,
|
|
};
|
|
|
|
static struct file_system_type bm_fs_type = {
|
|
.owner = THIS_MODULE,
|
|
.name = "binfmt_misc",
|
|
.init_fs_context = bm_init_fs_context,
|
|
.kill_sb = kill_litter_super,
|
|
};
|
|
MODULE_ALIAS_FS("binfmt_misc");
|
|
|
|
static int __init init_misc_binfmt(void)
|
|
{
|
|
int err = register_filesystem(&bm_fs_type);
|
|
if (!err)
|
|
insert_binfmt(&misc_format);
|
|
if (!register_sysctl_mount_point("fs/binfmt_misc")) {
|
|
pr_warn("Failed to create fs/binfmt_misc sysctl mount point");
|
|
return -ENOMEM;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void __exit exit_misc_binfmt(void)
|
|
{
|
|
unregister_binfmt(&misc_format);
|
|
unregister_filesystem(&bm_fs_type);
|
|
}
|
|
|
|
core_initcall(init_misc_binfmt);
|
|
module_exit(exit_misc_binfmt);
|
|
MODULE_LICENSE("GPL");
|