fs/binfmt_aout.c - linux - Git at Google

 /*
  *  linux/fs/binfmt_aout.c
  *
  *  Copyright (C) 1991, 1992, 1996  Linus Torvalds
  */

 #include <linux/module.h>

 #include <linux/time.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/mman.h>
 #include <linux/a.out.h>
 #include <linux/errno.h>
 #include <linux/signal.h>
 #include <linux/string.h>
 #include <linux/fs.h>
 #include <linux/file.h>
 #include <linux/stat.h>
 #include <linux/fcntl.h>
 #include <linux/ptrace.h>
 #include <linux/user.h>
 #include <linux/binfmts.h>
 #include <linux/personality.h>
 #include <linux/init.h>
 #include <linux/coredump.h>
 #include <linux/slab.h>
 #include <linux/sched/task_stack.h>

 #include <linux/uaccess.h>
 #include <asm/cacheflush.h>

 static int load_aout_binary(struct linux_binprm *);
 static int load_aout_library(struct file*);

 static struct linux_binfmt aout_format = {
 	.module		= THIS_MODULE,
 	.load_binary	= load_aout_binary,
 	.load_shlib	= load_aout_library,
 };

 #define BAD_ADDR(x)	((unsigned long)(x) >= TASK_SIZE)

 static int set_brk(unsigned long start, unsigned long end)
 {
 	start = PAGE_ALIGN(start);
 	end = PAGE_ALIGN(end);
 	if (end > start)
 		return vm_brk(start, end - start);
 	return 0;
 }

 /*
  * create_aout_tables() parses the env- and arg-strings in new user
  * memory and creates the pointer tables from them, and puts their
  * addresses on the "stack", returning the new stack pointer value.
  */
 static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
 {
 	char __user * __user *argv;
 	char __user * __user *envp;
 	unsigned long __user *sp;
 	int argc = bprm->argc;
 	int envc = bprm->envc;

 	sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
 #ifdef __alpha__
 /* whee.. test-programs are so much fun. */
 	put_user(0, --sp);
 	put_user(0, --sp);
 	if (bprm->loader) {
 		put_user(0, --sp);
 		put_user(1003, --sp);
 		put_user(bprm->loader, --sp);
 		put_user(1002, --sp);
 	}
 	put_user(bprm->exec, --sp);
 	put_user(1001, --sp);
 #endif
 	sp -= envc+1;
 	envp = (char __user * __user *) sp;
 	sp -= argc+1;
 	argv = (char __user * __user *) sp;
 #ifndef __alpha__
 	put_user((unsigned long) envp,--sp);
 	put_user((unsigned long) argv,--sp);
 #endif
 	put_user(argc,--sp);
 	current->mm->arg_start = (unsigned long) p;
 	while (argc-->0) {
 		char c;
 		put_user(p,argv++);
 		do {
 			get_user(c,p++);
 		} while (c);
 	}
 	put_user(NULL,argv);
 	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 	while (envc-->0) {
 		char c;
 		put_user(p,envp++);
 		do {
 			get_user(c,p++);
 		} while (c);
 	}
 	put_user(NULL,envp);
 	current->mm->env_end = (unsigned long) p;
 	return sp;
 }

 /*
  * These are the functions used to load a.out style executables and shared
  * libraries.  There is no binary dependent code anywhere else.
  */

 static int load_aout_binary(struct linux_binprm * bprm)
 {
 	struct pt_regs *regs = current_pt_regs();
 	struct exec ex;
 	unsigned long error;
 	unsigned long fd_offset;
 	unsigned long rlim;
 	int retval;

 	ex = *((struct exec *) bprm->buf);		/* exec-header */
 	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 	     N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 	    N_TRSIZE(ex) || N_DRSIZE(ex) ||
 	    i_size_read(file_inode(bprm->file)) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 		return -ENOEXEC;
 	}

 	/*
 	 * Requires a mmap handler. This prevents people from using a.out
 	 * as part of an exploit attack against /proc-related vulnerabilities.
 	 */
 	if (!bprm->file->f_op->mmap)
 		return -ENOEXEC;

 	fd_offset = N_TXTOFF(ex);

 	/* Check initial limits. This avoids letting people circumvent
 	 * size limits imposed on them by creating programs with large
 	 * arrays in the data or bss.
 	 */
 	rlim = rlimit(RLIMIT_DATA);
 	if (rlim >= RLIM_INFINITY)
 		rlim = ~0;
 	if (ex.a_data + ex.a_bss > rlim)
 		return -ENOMEM;

 	/* Flush all traces of the currently running executable */
 	retval = flush_old_exec(bprm);
 	if (retval)
 		return retval;

 	/* OK, This is the point of no return */
 #ifdef __alpha__
 	SET_AOUT_PERSONALITY(bprm, ex);
 #else
 	set_personality(PER_LINUX);
 #endif
 	setup_new_exec(bprm);

 	current->mm->end_code = ex.a_text +
 		(current->mm->start_code = N_TXTADDR(ex));
 	current->mm->end_data = ex.a_data +
 		(current->mm->start_data = N_DATADDR(ex));
 	current->mm->brk = ex.a_bss +
 		(current->mm->start_brk = N_BSSADDR(ex));

 	retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
 	if (retval < 0)
 		return retval;

 	install_exec_creds(bprm);

 	if (N_MAGIC(ex) == OMAGIC) {
 		unsigned long text_addr, map_size;
 		loff_t pos;

 		text_addr = N_TXTADDR(ex);

 #ifdef __alpha__
 		pos = fd_offset;
 		map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
 #else
 		pos = 32;
 		map_size = ex.a_text+ex.a_data;
 #endif
 		error = vm_brk(text_addr & PAGE_MASK, map_size);
 		if (error)
 			return error;

 		error = read_code(bprm->file, text_addr, pos,
 				  ex.a_text+ex.a_data);
 		if ((signed long)error < 0)
 			return error;
 	} else {
 		if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 		    (N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
 		{
 			printk(KERN_NOTICE "executable not page aligned\n");
 		}

 		if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
 		{
 			printk(KERN_WARNING
 			       "fd_offset is not page aligned. Please convert program: %pD\n",
 			       bprm->file);
 		}

 		if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
 			error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 			if (error)
 				return error;

 			read_code(bprm->file, N_TXTADDR(ex), fd_offset,
 				  ex.a_text + ex.a_data);
 			goto beyond_if;
 		}

 		error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 			PROT_READ | PROT_EXEC,
 			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 			fd_offset);

 		if (error != N_TXTADDR(ex))
 			return error;

 		error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 				PROT_READ | PROT_WRITE | PROT_EXEC,
 				MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 				fd_offset + ex.a_text);
 		if (error != N_DATADDR(ex))
 			return error;
 	}
 beyond_if:
 	set_binfmt(&aout_format);

 	retval = set_brk(current->mm->start_brk, current->mm->brk);
 	if (retval < 0)
 		return retval;

 	current->mm->start_stack =
 		(unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
 #ifdef __alpha__
 	regs->gp = ex.a_gpvalue;
 #endif
 	finalize_exec(bprm);
 	start_thread(regs, ex.a_entry, current->mm->start_stack);
 	return 0;
 }

 static int load_aout_library(struct file *file)
 {
 	struct inode * inode;
 	unsigned long bss, start_addr, len;
 	unsigned long error;
 	int retval;
 	struct exec ex;
 	loff_t pos = 0;

 	inode = file_inode(file);

 	retval = -ENOEXEC;
 	error = kernel_read(file, &ex, sizeof(ex), &pos);
 	if (error != sizeof(ex))
 		goto out;

 	/* We come in here for the regular a.out style of shared libraries */
 	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 	    N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 	    i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 		goto out;
 	}

 	/*
 	 * Requires a mmap handler. This prevents people from using a.out
 	 * as part of an exploit attack against /proc-related vulnerabilities.
 	 */
 	if (!file->f_op->mmap)
 		goto out;

 	if (N_FLAGS(ex))
 		goto out;

 	/* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 	   this off to get the starting address for the page */

 	start_addr =  ex.a_entry & 0xfffff000;

 	if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 		if (printk_ratelimit())
 		{
 			printk(KERN_WARNING
 			       "N_TXTOFF is not page aligned. Please convert library: %pD\n",
 			       file);
 		}
 		retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 		if (retval)
 			goto out;

 		read_code(file, start_addr, N_TXTOFF(ex),
 			  ex.a_text + ex.a_data);
 		retval = 0;
 		goto out;
 	}
 	/* Now use mmap to map the library into memory. */
 	error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
 			PROT_READ | PROT_WRITE | PROT_EXEC,
 			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
 			N_TXTOFF(ex));
 	retval = error;
 	if (error != start_addr)
 		goto out;

 	len = PAGE_ALIGN(ex.a_text + ex.a_data);
 	bss = ex.a_text + ex.a_data + ex.a_bss;
 	if (bss > len) {
 		retval = vm_brk(start_addr + len, bss - len);
 		if (retval)
 			goto out;
 	}
 	retval = 0;
 out:
 	return retval;
 }

 static int __init init_aout_binfmt(void)
 {
 	register_binfmt(&aout_format);
 	return 0;
 }

 static void __exit exit_aout_binfmt(void)
 {
 	unregister_binfmt(&aout_format);
 }

 core_initcall(init_aout_binfmt);
 module_exit(exit_aout_binfmt);
 MODULE_LICENSE("GPL");
	/*
	* linux/fs/binfmt_aout.c
	*
	* Copyright (C) 1991, 1992, 1996 Linus Torvalds
	*/

	#include <linux/module.h>

	#include <linux/time.h>
	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/mman.h>
	#include <linux/a.out.h>
	#include <linux/errno.h>
	#include <linux/signal.h>
	#include <linux/string.h>
	#include <linux/fs.h>
	#include <linux/file.h>
	#include <linux/stat.h>
	#include <linux/fcntl.h>
	#include <linux/ptrace.h>
	#include <linux/user.h>
	#include <linux/binfmts.h>
	#include <linux/personality.h>
	#include <linux/init.h>
	#include <linux/coredump.h>
	#include <linux/slab.h>
	#include <linux/sched/task_stack.h>

	#include <linux/uaccess.h>
	#include <asm/cacheflush.h>

	static int load_aout_binary(struct linux_binprm *);
	static int load_aout_library(struct file*);

	static struct linux_binfmt aout_format = {
	.module = THIS_MODULE,
	.load_binary = load_aout_binary,
	.load_shlib = load_aout_library,
	};

	#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)

	static int set_brk(unsigned long start, unsigned long end)
	{
	start = PAGE_ALIGN(start);
	end = PAGE_ALIGN(end);
	if (end > start)
	return vm_brk(start, end - start);
	return 0;
	}

	/*
	* create_aout_tables() parses the env- and arg-strings in new user
	* memory and creates the pointer tables from them, and puts their
	* addresses on the "stack", returning the new stack pointer value.
	*/
	static unsigned long __user create_aout_tables(char __user p, struct linux_binprm * bprm)
	{
	char __user * __user *argv;
	char __user * __user *envp;
	unsigned long __user *sp;
	int argc = bprm->argc;
	int envc = bprm->envc;

	sp = (void __user )((-(unsigned long)sizeof(char )) & (unsigned long) p);
	#ifdef __alpha__
	/* whee.. test-programs are so much fun. */
	put_user(0, --sp);
	put_user(0, --sp);
	if (bprm->loader) {
	put_user(0, --sp);
	put_user(1003, --sp);
	put_user(bprm->loader, --sp);
	put_user(1002, --sp);
	}
	put_user(bprm->exec, --sp);
	put_user(1001, --sp);
	#endif
	sp -= envc+1;
	envp = (char __user * __user *) sp;
	sp -= argc+1;
	argv = (char __user * __user *) sp;
	#ifndef __alpha__
	put_user((unsigned long) envp,--sp);
	put_user((unsigned long) argv,--sp);
	#endif
	put_user(argc,--sp);
	current->mm->arg_start = (unsigned long) p;
	while (argc-->0) {
	char c;
	put_user(p,argv++);
	do {
	get_user(c,p++);
	} while (c);
	}
	put_user(NULL,argv);
	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
	while (envc-->0) {
	char c;
	put_user(p,envp++);
	do {
	get_user(c,p++);
	} while (c);
	}
	put_user(NULL,envp);
	current->mm->env_end = (unsigned long) p;
	return sp;
	}

	/*
	* These are the functions used to load a.out style executables and shared
	* libraries. There is no binary dependent code anywhere else.
	*/

	static int load_aout_binary(struct linux_binprm * bprm)
	{
	struct pt_regs *regs = current_pt_regs();
	struct exec ex;
	unsigned long error;
	unsigned long fd_offset;
	unsigned long rlim;
	int retval;

	ex = ((struct exec ) bprm->buf); /* exec-header */
	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
	N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) \|\|
	N_TRSIZE(ex) \|\| N_DRSIZE(ex) \|\|
	i_size_read(file_inode(bprm->file)) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
	return -ENOEXEC;
	}

	/*
	* Requires a mmap handler. This prevents people from using a.out
	* as part of an exploit attack against /proc-related vulnerabilities.
	*/
	if (!bprm->file->f_op->mmap)
	return -ENOEXEC;

	fd_offset = N_TXTOFF(ex);

	/* Check initial limits. This avoids letting people circumvent
	* size limits imposed on them by creating programs with large
	* arrays in the data or bss.
	*/
	rlim = rlimit(RLIMIT_DATA);
	if (rlim >= RLIM_INFINITY)
	rlim = ~0;
	if (ex.a_data + ex.a_bss > rlim)
	return -ENOMEM;

	/* Flush all traces of the currently running executable */
	retval = flush_old_exec(bprm);
	if (retval)
	return retval;

	/* OK, This is the point of no return */
	#ifdef __alpha__
	SET_AOUT_PERSONALITY(bprm, ex);
	#else
	set_personality(PER_LINUX);
	#endif
	setup_new_exec(bprm);

	current->mm->end_code = ex.a_text +
	(current->mm->start_code = N_TXTADDR(ex));
	current->mm->end_data = ex.a_data +
	(current->mm->start_data = N_DATADDR(ex));
	current->mm->brk = ex.a_bss +
	(current->mm->start_brk = N_BSSADDR(ex));

	retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
	if (retval < 0)
	return retval;

	install_exec_creds(bprm);

	if (N_MAGIC(ex) == OMAGIC) {
	unsigned long text_addr, map_size;
	loff_t pos;

	text_addr = N_TXTADDR(ex);

	#ifdef __alpha__
	pos = fd_offset;
	map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
	#else
	pos = 32;
	map_size = ex.a_text+ex.a_data;
	#endif
	error = vm_brk(text_addr & PAGE_MASK, map_size);
	if (error)
	return error;

	error = read_code(bprm->file, text_addr, pos,
	ex.a_text+ex.a_data);
	if ((signed long)error < 0)
	return error;
	} else {
	if ((ex.a_text & 0xfff \|\| ex.a_data & 0xfff) &&
	(N_MAGIC(ex) != NMAGIC) && printk_ratelimit())
	{
	printk(KERN_NOTICE "executable not page aligned\n");
	}

	if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit())
	{
	printk(KERN_WARNING
	"fd_offset is not page aligned. Please convert program: %pD\n",
	bprm->file);
	}

	if (!bprm->file->f_op->mmap\|\|((fd_offset & ~PAGE_MASK) != 0)) {
	error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
	if (error)
	return error;

	read_code(bprm->file, N_TXTADDR(ex), fd_offset,
	ex.a_text + ex.a_data);
	goto beyond_if;
	}

	error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
	PROT_READ \| PROT_EXEC,
	MAP_FIXED \| MAP_PRIVATE \| MAP_DENYWRITE \| MAP_EXECUTABLE,
	fd_offset);

	if (error != N_TXTADDR(ex))
	return error;

	error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
	PROT_READ \| PROT_WRITE \| PROT_EXEC,
	MAP_FIXED \| MAP_PRIVATE \| MAP_DENYWRITE \| MAP_EXECUTABLE,
	fd_offset + ex.a_text);
	if (error != N_DATADDR(ex))
	return error;
	}
	beyond_if:
	set_binfmt(&aout_format);

	retval = set_brk(current->mm->start_brk, current->mm->brk);
	if (retval < 0)
	return retval;

	current->mm->start_stack =
	(unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
	#ifdef __alpha__
	regs->gp = ex.a_gpvalue;
	#endif
	finalize_exec(bprm);
	start_thread(regs, ex.a_entry, current->mm->start_stack);
	return 0;
	}

	static int load_aout_library(struct file *file)
	{
	struct inode * inode;
	unsigned long bss, start_addr, len;
	unsigned long error;
	int retval;
	struct exec ex;
	loff_t pos = 0;

	inode = file_inode(file);

	retval = -ENOEXEC;
	error = kernel_read(file, &ex, sizeof(ex), &pos);
	if (error != sizeof(ex))
	goto out;

	/* We come in here for the regular a.out style of shared libraries */
	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) \|\| N_TRSIZE(ex) \|\|
	N_DRSIZE(ex) \|\| ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) \|\|
	i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
	goto out;
	}

	/*
	* Requires a mmap handler. This prevents people from using a.out
	* as part of an exploit attack against /proc-related vulnerabilities.
	*/
	if (!file->f_op->mmap)
	goto out;

	if (N_FLAGS(ex))
	goto out;

	/* For QMAGIC, the starting address is 0x20 into the page. We mask
	this off to get the starting address for the page */

	start_addr = ex.a_entry & 0xfffff000;

	if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
	if (printk_ratelimit())
	{
	printk(KERN_WARNING
	"N_TXTOFF is not page aligned. Please convert library: %pD\n",
	file);
	}
	retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
	if (retval)
	goto out;

	read_code(file, start_addr, N_TXTOFF(ex),
	ex.a_text + ex.a_data);
	retval = 0;
	goto out;
	}
	/* Now use mmap to map the library into memory. */
	error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
	PROT_READ \| PROT_WRITE \| PROT_EXEC,
	MAP_FIXED \| MAP_PRIVATE \| MAP_DENYWRITE,
	N_TXTOFF(ex));
	retval = error;
	if (error != start_addr)
	goto out;

	len = PAGE_ALIGN(ex.a_text + ex.a_data);
	bss = ex.a_text + ex.a_data + ex.a_bss;
	if (bss > len) {
	retval = vm_brk(start_addr + len, bss - len);
	if (retval)
	goto out;
	}
	retval = 0;
	out:
	return retval;
	}

	static int __init init_aout_binfmt(void)
	{
	register_binfmt(&aout_format);
	return 0;
	}

	static void __exit exit_aout_binfmt(void)
	{
	unregister_binfmt(&aout_format);
	}

	core_initcall(init_aout_binfmt);
	module_exit(exit_aout_binfmt);
	MODULE_LICENSE("GPL");