343 lines
8.2 KiB
C
343 lines
8.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/fs/binfmt_aout.c
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*
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* Copyright (C) 1991, 1992, 1996 Linus Torvalds
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*/
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#include <linux/module.h>
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#include <linux/time.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/mman.h>
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#include <linux/a.out.h>
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#include <linux/errno.h>
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#include <linux/signal.h>
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#include <linux/string.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/stat.h>
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#include <linux/fcntl.h>
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#include <linux/ptrace.h>
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#include <linux/user.h>
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#include <linux/binfmts.h>
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#include <linux/personality.h>
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#include <linux/init.h>
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#include <linux/coredump.h>
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#include <linux/slab.h>
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#include <linux/sched/task_stack.h>
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#include <linux/uaccess.h>
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#include <asm/cacheflush.h>
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static int load_aout_binary(struct linux_binprm *);
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static int load_aout_library(struct file*);
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static struct linux_binfmt aout_format = {
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.module = THIS_MODULE,
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.load_binary = load_aout_binary,
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.load_shlib = load_aout_library,
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};
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#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
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static int set_brk(unsigned long start, unsigned long end)
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{
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start = PAGE_ALIGN(start);
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end = PAGE_ALIGN(end);
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if (end > start)
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return vm_brk(start, end - start);
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return 0;
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}
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/*
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* create_aout_tables() parses the env- and arg-strings in new user
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* memory and creates the pointer tables from them, and puts their
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* addresses on the "stack", returning the new stack pointer value.
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*/
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static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
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{
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char __user * __user *argv;
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char __user * __user *envp;
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unsigned long __user *sp;
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int argc = bprm->argc;
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int envc = bprm->envc;
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sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
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#ifdef __alpha__
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/* whee.. test-programs are so much fun. */
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put_user(0, --sp);
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put_user(0, --sp);
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if (bprm->loader) {
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put_user(0, --sp);
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put_user(1003, --sp);
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put_user(bprm->loader, --sp);
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put_user(1002, --sp);
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}
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put_user(bprm->exec, --sp);
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put_user(1001, --sp);
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#endif
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sp -= envc+1;
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envp = (char __user * __user *) sp;
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sp -= argc+1;
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argv = (char __user * __user *) sp;
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#ifndef __alpha__
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put_user((unsigned long) envp,--sp);
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put_user((unsigned long) argv,--sp);
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#endif
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put_user(argc,--sp);
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current->mm->arg_start = (unsigned long) p;
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while (argc-->0) {
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char c;
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put_user(p,argv++);
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do {
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get_user(c,p++);
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} while (c);
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}
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put_user(NULL,argv);
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current->mm->arg_end = current->mm->env_start = (unsigned long) p;
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while (envc-->0) {
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char c;
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put_user(p,envp++);
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do {
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get_user(c,p++);
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} while (c);
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}
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put_user(NULL,envp);
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current->mm->env_end = (unsigned long) p;
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return sp;
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}
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/*
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* These are the functions used to load a.out style executables and shared
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* libraries. There is no binary dependent code anywhere else.
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*/
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static int load_aout_binary(struct linux_binprm * bprm)
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{
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struct pt_regs *regs = current_pt_regs();
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struct exec ex;
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unsigned long error;
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unsigned long fd_offset;
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unsigned long rlim;
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int retval;
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ex = *((struct exec *) bprm->buf); /* exec-header */
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if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
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N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
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N_TRSIZE(ex) || N_DRSIZE(ex) ||
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i_size_read(file_inode(bprm->file)) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
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return -ENOEXEC;
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}
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/*
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* Requires a mmap handler. This prevents people from using a.out
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* as part of an exploit attack against /proc-related vulnerabilities.
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*/
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if (!bprm->file->f_op->mmap)
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return -ENOEXEC;
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fd_offset = N_TXTOFF(ex);
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/* Check initial limits. This avoids letting people circumvent
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* size limits imposed on them by creating programs with large
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* arrays in the data or bss.
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*/
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rlim = rlimit(RLIMIT_DATA);
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if (rlim >= RLIM_INFINITY)
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rlim = ~0;
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if (ex.a_data + ex.a_bss > rlim)
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return -ENOMEM;
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/* Flush all traces of the currently running executable */
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retval = begin_new_exec(bprm);
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if (retval)
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return retval;
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/* OK, This is the point of no return */
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#ifdef __alpha__
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SET_AOUT_PERSONALITY(bprm, ex);
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#else
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set_personality(PER_LINUX);
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#endif
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setup_new_exec(bprm);
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current->mm->end_code = ex.a_text +
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(current->mm->start_code = N_TXTADDR(ex));
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current->mm->end_data = ex.a_data +
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(current->mm->start_data = N_DATADDR(ex));
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current->mm->brk = ex.a_bss +
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(current->mm->start_brk = N_BSSADDR(ex));
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retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
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if (retval < 0)
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return retval;
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if (N_MAGIC(ex) == OMAGIC) {
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unsigned long text_addr, map_size;
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loff_t pos;
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text_addr = N_TXTADDR(ex);
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#ifdef __alpha__
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pos = fd_offset;
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map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
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#else
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pos = 32;
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map_size = ex.a_text+ex.a_data;
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#endif
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error = vm_brk(text_addr & PAGE_MASK, map_size);
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if (error)
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return error;
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error = read_code(bprm->file, text_addr, pos,
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ex.a_text+ex.a_data);
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if ((signed long)error < 0)
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return error;
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} else {
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if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
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(N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
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{
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printk(KERN_NOTICE "executable not page aligned\n");
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}
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if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
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{
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printk(KERN_WARNING
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"fd_offset is not page aligned. Please convert program: %pD\n",
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bprm->file);
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}
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if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
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error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
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if (error)
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return error;
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read_code(bprm->file, N_TXTADDR(ex), fd_offset,
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ex.a_text + ex.a_data);
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goto beyond_if;
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}
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error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
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PROT_READ | PROT_EXEC, MAP_FIXED | MAP_PRIVATE,
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fd_offset);
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if (error != N_TXTADDR(ex))
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return error;
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error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_FIXED | MAP_PRIVATE,
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fd_offset + ex.a_text);
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if (error != N_DATADDR(ex))
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return error;
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}
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beyond_if:
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set_binfmt(&aout_format);
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retval = set_brk(current->mm->start_brk, current->mm->brk);
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if (retval < 0)
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return retval;
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current->mm->start_stack =
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(unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
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#ifdef __alpha__
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regs->gp = ex.a_gpvalue;
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#endif
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finalize_exec(bprm);
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start_thread(regs, ex.a_entry, current->mm->start_stack);
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return 0;
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}
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static int load_aout_library(struct file *file)
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{
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struct inode * inode;
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unsigned long bss, start_addr, len;
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unsigned long error;
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int retval;
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struct exec ex;
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loff_t pos = 0;
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inode = file_inode(file);
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retval = -ENOEXEC;
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error = kernel_read(file, &ex, sizeof(ex), &pos);
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if (error != sizeof(ex))
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goto out;
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/* We come in here for the regular a.out style of shared libraries */
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if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
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N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
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i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
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goto out;
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}
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/*
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* Requires a mmap handler. This prevents people from using a.out
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* as part of an exploit attack against /proc-related vulnerabilities.
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*/
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if (!file->f_op->mmap)
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goto out;
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if (N_FLAGS(ex))
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goto out;
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/* For QMAGIC, the starting address is 0x20 into the page. We mask
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this off to get the starting address for the page */
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start_addr = ex.a_entry & 0xfffff000;
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if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
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if (printk_ratelimit())
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{
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printk(KERN_WARNING
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"N_TXTOFF is not page aligned. Please convert library: %pD\n",
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file);
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}
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retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
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if (retval)
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goto out;
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read_code(file, start_addr, N_TXTOFF(ex),
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ex.a_text + ex.a_data);
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retval = 0;
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goto out;
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}
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/* Now use mmap to map the library into memory. */
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error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_FIXED | MAP_PRIVATE,
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N_TXTOFF(ex));
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retval = error;
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if (error != start_addr)
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goto out;
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len = PAGE_ALIGN(ex.a_text + ex.a_data);
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bss = ex.a_text + ex.a_data + ex.a_bss;
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if (bss > len) {
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retval = vm_brk(start_addr + len, bss - len);
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if (retval)
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goto out;
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}
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retval = 0;
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out:
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return retval;
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}
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static int __init init_aout_binfmt(void)
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{
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register_binfmt(&aout_format);
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return 0;
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}
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static void __exit exit_aout_binfmt(void)
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{
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unregister_binfmt(&aout_format);
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}
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core_initcall(init_aout_binfmt);
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module_exit(exit_aout_binfmt);
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MODULE_LICENSE("GPL");
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