8b72ca9004
The code in prepare_binary_handler needs to be run every time search_binary_handler is called so move the call into search_binary_handler itself to make the code simpler and easier to understand. Link: https://lkml.kernel.org/r/87d070zrvx.fsf_-_@x220.int.ebiederm.org Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
116 lines
2.8 KiB
C
116 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/fs/binfmt_em86.c
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*
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* Based on linux/fs/binfmt_script.c
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* Copyright (C) 1996 Martin von Löwis
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* original #!-checking implemented by tytso.
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*
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* em86 changes Copyright (C) 1997 Jim Paradis
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*/
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/stat.h>
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#include <linux/binfmts.h>
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#include <linux/elf.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/errno.h>
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#define EM86_INTERP "/usr/bin/em86"
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#define EM86_I_NAME "em86"
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static int load_em86(struct linux_binprm *bprm)
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{
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const char *i_name, *i_arg;
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char *interp;
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struct file * file;
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int retval;
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struct elfhdr elf_ex;
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/* Make sure this is a Linux/Intel ELF executable... */
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elf_ex = *((struct elfhdr *)bprm->buf);
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if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
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return -ENOEXEC;
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/* First of all, some simple consistency checks */
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if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) ||
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(!((elf_ex.e_machine == EM_386) || (elf_ex.e_machine == EM_486))) ||
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!bprm->file->f_op->mmap) {
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return -ENOEXEC;
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}
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/* Need to be able to load the file after exec */
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if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
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return -ENOENT;
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allow_write_access(bprm->file);
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fput(bprm->file);
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bprm->file = NULL;
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/* Unlike in the script case, we don't have to do any hairy
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* parsing to find our interpreter... it's hardcoded!
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*/
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interp = EM86_INTERP;
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i_name = EM86_I_NAME;
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i_arg = NULL; /* We reserve the right to add an arg later */
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/*
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* Splice in (1) the interpreter's name for argv[0]
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* (2) (optional) argument to interpreter
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* (3) filename of emulated file (replace argv[0])
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*
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* This is done in reverse order, because of how the
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* user environment and arguments are stored.
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*/
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remove_arg_zero(bprm);
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retval = copy_strings_kernel(1, &bprm->filename, bprm);
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if (retval < 0) return retval;
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bprm->argc++;
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if (i_arg) {
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retval = copy_strings_kernel(1, &i_arg, bprm);
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if (retval < 0) return retval;
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bprm->argc++;
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}
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retval = copy_strings_kernel(1, &i_name, bprm);
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if (retval < 0) return retval;
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bprm->argc++;
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/*
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* OK, now restart the process with the interpreter's inode.
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* Note that we use open_exec() as the name is now in kernel
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* space, and we don't need to copy it.
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*/
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file = open_exec(interp);
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if (IS_ERR(file))
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return PTR_ERR(file);
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bprm->file = file;
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return search_binary_handler(bprm);
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}
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static struct linux_binfmt em86_format = {
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.module = THIS_MODULE,
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.load_binary = load_em86,
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};
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static int __init init_em86_binfmt(void)
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{
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register_binfmt(&em86_format);
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return 0;
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}
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static void __exit exit_em86_binfmt(void)
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{
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unregister_binfmt(&em86_format);
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}
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core_initcall(init_em86_binfmt);
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module_exit(exit_em86_binfmt);
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MODULE_LICENSE("GPL");
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