C++ put_files_struct函数代码示例

//.........这里部分代码省略.........
	if (unshare_flags & CLONE_NEWUSER)
		unshare_flags |= CLONE_THREAD | CLONE_FS;
	/*
	 * If unsharing a pid namespace must also unshare the thread.
	 */
	if (unshare_flags & CLONE_NEWPID)
		unshare_flags |= CLONE_THREAD;
	/*
	 * If unsharing a thread from a thread group, must also unshare vm.
	 */
	if (unshare_flags & CLONE_THREAD)
		unshare_flags |= CLONE_VM;
	/*
	 * If unsharing vm, must also unshare signal handlers.
	 */
	if (unshare_flags & CLONE_VM)
		unshare_flags |= CLONE_SIGHAND;
	/*
	 * If unsharing namespace, must also unshare filesystem information.
	 */
	if (unshare_flags & CLONE_NEWNS)
		unshare_flags |= CLONE_FS;

	err = check_unshare_flags(unshare_flags);
	if (err)
		goto bad_unshare_out;
	/*
	 * CLONE_NEWIPC must also detach from the undolist: after switching
	 * to a new ipc namespace, the semaphore arrays from the old
	 * namespace are unreachable.
	 */
	if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM))
		do_sysvsem = 1;
	err = unshare_fs(unshare_flags, &new_fs);
	if (err)
		goto bad_unshare_out;
	err = unshare_fd(unshare_flags, &new_fd);
	if (err)
		goto bad_unshare_cleanup_fs;
	err = unshare_userns(unshare_flags, &new_cred);
	if (err)
		goto bad_unshare_cleanup_fd;
	err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy,
					 new_cred, new_fs);
	if (err)
		goto bad_unshare_cleanup_cred;

	if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) {
		if (do_sysvsem) {
			/*
			 * CLONE_SYSVSEM is equivalent to sys_exit().
			 */
			exit_sem(current);
		}

		if (new_nsproxy)
			switch_task_namespaces(current, new_nsproxy);

		task_lock(current);

		if (new_fs) {
			fs = current->fs;
			spin_lock(&fs->lock);
			current->fs = new_fs;
			if (--fs->users)
				new_fs = NULL;
			else
				new_fs = fs;
			spin_unlock(&fs->lock);
		}

		if (new_fd) {
			fd = current->files;
			current->files = new_fd;
			new_fd = fd;
		}

		task_unlock(current);

		if (new_cred) {
			/* Install the new user namespace */
			commit_creds(new_cred);
			new_cred = NULL;
		}
	}

bad_unshare_cleanup_cred:
	if (new_cred)
		put_cred(new_cred);
bad_unshare_cleanup_fd:
	if (new_fd)
		put_files_struct(new_fd);

bad_unshare_cleanup_fs:
	if (new_fs)
		free_fs_struct(new_fs);

bad_unshare_out:
	return err;
}

//.........这里部分代码省略.........
		goto bad_unshare_cleanup_uts;

	if (new_ns || new_uts || new_ipc) {
		old_nsproxy = current->nsproxy;
		new_nsproxy = dup_namespaces(old_nsproxy);
		if (!new_nsproxy) {
			err = -ENOMEM;
			goto bad_unshare_cleanup_ipc;
		}
	}

	if (new_fs || new_ns || new_mm || new_fd || new_ulist ||
				new_uts || new_ipc) {

		task_lock(current);

		if (new_nsproxy) {
			current->nsproxy = new_nsproxy;
			new_nsproxy = old_nsproxy;
		}

		if (new_fs) {
			fs = current->fs;
			current->fs = new_fs;
			new_fs = fs;
		}

		if (new_ns) {
			ns = current->nsproxy->mnt_ns;
			current->nsproxy->mnt_ns = new_ns;
			new_ns = ns;
		}

		if (new_mm) {
			mm = current->mm;
			active_mm = current->active_mm;
			current->mm = new_mm;
			current->active_mm = new_mm;
			activate_mm(active_mm, new_mm);
			new_mm = mm;
		}

		if (new_fd) {
			fd = current->files;
			current->files = new_fd;
			new_fd = fd;
		}

		if (new_uts) {
			uts = current->nsproxy->uts_ns;
			current->nsproxy->uts_ns = new_uts;
			new_uts = uts;
		}

		if (new_ipc) {
			ipc = current->nsproxy->ipc_ns;
			current->nsproxy->ipc_ns = new_ipc;
			new_ipc = ipc;
		}

		task_unlock(current);
	}

	if (new_nsproxy)
		put_nsproxy(new_nsproxy);

bad_unshare_cleanup_ipc:
	if (new_ipc)
		put_ipc_ns(new_ipc);

bad_unshare_cleanup_uts:
	if (new_uts)
		put_uts_ns(new_uts);

bad_unshare_cleanup_semundo:
bad_unshare_cleanup_fd:
	if (new_fd)
		put_files_struct(new_fd);

bad_unshare_cleanup_vm:
	if (new_mm)
		mmput(new_mm);

bad_unshare_cleanup_sigh:
	if (new_sigh)
		if (atomic_dec_and_test(&new_sigh->count))
			kmem_cache_free(sighand_cachep, new_sigh);

bad_unshare_cleanup_ns:
	if (new_ns)
		put_mnt_ns(new_ns);

bad_unshare_cleanup_fs:
	if (new_fs)
		put_fs_struct(new_fs);

bad_unshare_cleanup_thread:
bad_unshare_out:
	return err;
}

SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
{
	struct fs_struct *fs, *new_fs = NULL;
	struct files_struct *fd, *new_fd = NULL;
	struct nsproxy *new_nsproxy = NULL;
	int do_sysvsem = 0;
	int err;

	err = check_unshare_flags(unshare_flags);
	if (err)
		goto bad_unshare_out;

	if (unshare_flags & CLONE_NEWNS)
		unshare_flags |= CLONE_FS;
	if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM))
		do_sysvsem = 1;
	err = unshare_fs(unshare_flags, &new_fs);
	if (err)
		goto bad_unshare_out;
	err = unshare_fd(unshare_flags, &new_fd);
	if (err)
		goto bad_unshare_cleanup_fs;
	err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, new_fs);
	if (err)
		goto bad_unshare_cleanup_fd;

	if (new_fs || new_fd || do_sysvsem || new_nsproxy) {
		if (do_sysvsem) {
			exit_sem(current);
		}

		if (new_nsproxy) {
			switch_task_namespaces(current, new_nsproxy);
			new_nsproxy = NULL;
		}

		task_lock(current);

		if (new_fs) {
			fs = current->fs;
			spin_lock(&fs->lock);
			current->fs = new_fs;
			if (--fs->users)
				new_fs = NULL;
			else
				new_fs = fs;
			spin_unlock(&fs->lock);
		}

		if (new_fd) {
			fd = current->files;
			current->files = new_fd;
			new_fd = fd;
		}

		task_unlock(current);
	}

	if (new_nsproxy)
		put_nsproxy(new_nsproxy);

bad_unshare_cleanup_fd:
	if (new_fd)
		put_files_struct(new_fd);

bad_unshare_cleanup_fs:
	if (new_fs)
		free_fs_struct(new_fs);

bad_unshare_out:
	return err;
}

static long
eventfd_link_ioctl_copy(unsigned long arg)
{
	void __user *argp = (void __user *) arg;
	struct task_struct *task_target = NULL;
	struct file *file;
	struct files_struct *files;
	struct fdtable *fdt;
	struct eventfd_copy eventfd_copy;
	long ret = -EFAULT;

	if (copy_from_user(&eventfd_copy, argp, sizeof(struct eventfd_copy)))
		goto out;

	/*
	 * Find the task struct for the target pid
	 */
	ret = -ESRCH;

	task_target =
		get_pid_task(find_vpid(eventfd_copy.target_pid), PIDTYPE_PID);
	if (task_target == NULL) {
		pr_info("Unable to find pid %d\n", eventfd_copy.target_pid);
		goto out;
	}

	ret = -ESTALE;
	files = get_files_struct(current);
	if (files == NULL) {
		pr_info("Failed to get current files struct\n");
		goto out_task;
	}

	ret = -EBADF;
	file = fget_from_files(files, eventfd_copy.source_fd);

	if (file == NULL) {
		pr_info("Failed to get fd %d from source\n",
			eventfd_copy.source_fd);
		put_files_struct(files);
		goto out_task;
	}

	/*
	 * Release the existing eventfd in the source process
	 */
	spin_lock(&files->file_lock);
	fput(file);
	filp_close(file, files);
	fdt = files_fdtable(files);
	fdt->fd[eventfd_copy.source_fd] = NULL;
	spin_unlock(&files->file_lock);

	put_files_struct(files);

	/*
	 * Find the file struct associated with the target fd.
	 */

	ret = -ESTALE;
	files = get_files_struct(task_target);
	if (files == NULL) {
		pr_info("Failed to get target files struct\n");
		goto out_task;
	}

	ret = -EBADF;
	file = fget_from_files(files, eventfd_copy.target_fd);
	put_files_struct(files);

	if (file == NULL) {
		pr_info("Failed to get fd %d from target\n",
			eventfd_copy.target_fd);
		goto out_task;
	}

	/*
	 * Install the file struct from the target process into the
	 * file desciptor of the source process,
	 */

	fd_install(eventfd_copy.source_fd, file);
	ret = 0;

out_task:
	put_task_struct(task_target);
out:
	return ret;
}

static int CVE_2010_0307_linux2_6_16_load_elf_binary(struct linux_binprm * bprm, struct pt_regs * regs)
{
	struct file *interpreter = NULL; /* to shut gcc up */
 	unsigned long load_addr = 0, load_bias = 0;
	int load_addr_set = 0;
	char * elf_interpreter = NULL;
	unsigned int interpreter_type = INTERPRETER_NONE;
	unsigned char ibcs2_interpreter = 0;
	unsigned long error;
	struct elf_phdr * elf_ppnt, *elf_phdata;
	unsigned long elf_bss, elf_brk;
	int elf_exec_fileno;
	int retval, i;
	unsigned int size;
	unsigned long elf_entry, interp_load_addr = 0;
	unsigned long start_code, end_code, start_data, end_data;
	unsigned long reloc_func_desc = 0;
	char passed_fileno[6];
	struct files_struct *files;
	int have_pt_gnu_stack, executable_stack = EXSTACK_DEFAULT;
	unsigned long def_flags = 0;
	struct {
		struct elfhdr elf_ex;
		struct elfhdr interp_elf_ex;
  		struct exec interp_ex;
	} *loc;

	loc = kmalloc(sizeof(*loc), GFP_KERNEL);
	if (!loc) {
		retval = -ENOMEM;
		goto out_ret;
	}
	
	/* Get the exec-header */
	loc->elf_ex = *((struct elfhdr *) bprm->buf);

	retval = -ENOEXEC;
	/* First of all, some simple consistency checks */
	if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
		goto out;

	if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
		goto out;
	if (!elf_check_arch(&loc->elf_ex))
		goto out;
	if (!bprm->file->f_op||!bprm->file->f_op->mmap)
		goto out;

	/* Now read in all of the header information */

	if (loc->elf_ex.e_phentsize != sizeof(struct elf_phdr))
		goto out;
	if (loc->elf_ex.e_phnum < 1 ||
	 	loc->elf_ex.e_phnum > 65536U / sizeof(struct elf_phdr))
		goto out;
	size = loc->elf_ex.e_phnum * sizeof(struct elf_phdr);
	retval = -ENOMEM;
	elf_phdata = (struct elf_phdr *) kmalloc(size, GFP_KERNEL);
	if (!elf_phdata)
		goto out;

	retval = kernel_read(bprm->file, loc->elf_ex.e_phoff, (char *) elf_phdata, size);
	if (retval != size) {
		if (retval >= 0)
			retval = -EIO;
		goto out_free_ph;
	}

	files = current->files;		/* Refcounted so ok */
	retval = unshare_files();
	if (retval < 0)
		goto out_free_ph;
	if (files == current->files) {
		put_files_struct(files);
		files = NULL;
	}

	/* exec will make our files private anyway, but for the a.out
	   loader stuff we need to do it earlier */

	retval = get_unused_fd();
	if (retval < 0)
		goto out_free_fh;
	get_file(bprm->file);
	fd_install(elf_exec_fileno = retval, bprm->file);

	elf_ppnt = elf_phdata;
	elf_bss = 0;
	elf_brk = 0;

	start_code = ~0UL;
	end_code = 0;
	start_data = 0;
	end_data = 0;

	for (i = 0; i < loc->elf_ex.e_phnum; i++) {
		if (elf_ppnt->p_type == PT_INTERP) {
			/* This is the program interpreter used for
			 * shared libraries - for now assume that this
			 * is an a.out format binary
//.........这里部分代码省略.........

/*
 * unshare allows a process to 'unshare' part of the process
 * context which was originally shared using clone.  copy_*
 * functions used by do_fork() cannot be used here directly
 * because they modify an inactive task_struct that is being
 * constructed. Here we are modifying the current, active,
 * task_struct.
 */
asmlinkage long sys_unshare(unsigned long unshare_flags)
{
	int err = 0;
	struct fs_struct *fs, *new_fs = NULL;
	struct sighand_struct *new_sigh = NULL;
	struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL;
	struct files_struct *fd, *new_fd = NULL;
	struct sem_undo_list *new_ulist = NULL;
	struct nsproxy *new_nsproxy = NULL;

	check_unshare_flags(&unshare_flags);

	/* Return -EINVAL for all unsupported flags */
	err = -EINVAL;
	if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
				CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
				CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWUSER|
				CLONE_NEWNET))
		goto bad_unshare_out;

	if ((err = unshare_thread(unshare_flags)))
		goto bad_unshare_out;
	if ((err = unshare_fs(unshare_flags, &new_fs)))
		goto bad_unshare_cleanup_thread;
	if ((err = unshare_sighand(unshare_flags, &new_sigh)))
		goto bad_unshare_cleanup_fs;
	if ((err = unshare_vm(unshare_flags, &new_mm)))
		goto bad_unshare_cleanup_sigh;
	if ((err = unshare_fd(unshare_flags, &new_fd)))
		goto bad_unshare_cleanup_vm;
	if ((err = unshare_semundo(unshare_flags, &new_ulist)))
		goto bad_unshare_cleanup_fd;
	if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy,
			new_fs)))
		goto bad_unshare_cleanup_semundo;

	if (new_fs ||  new_mm || new_fd || new_ulist || new_nsproxy) {

		if (new_nsproxy) {
			switch_task_namespaces(current, new_nsproxy);
			new_nsproxy = NULL;
		}

		task_lock(current);

		if (new_fs) {
			fs = current->fs;
			current->fs = new_fs;
			new_fs = fs;
		}

		if (new_mm) {
			mm = current->mm;
			active_mm = current->active_mm;
			current->mm = new_mm;
			current->active_mm = new_mm;
			activate_mm(active_mm, new_mm);
			new_mm = mm;
		}

		if (new_fd) {
			fd = current->files;
			current->files = new_fd;
			new_fd = fd;
		}

		task_unlock(current);
	}

	if (new_nsproxy)
		put_nsproxy(new_nsproxy);

bad_unshare_cleanup_semundo:
bad_unshare_cleanup_fd:
	if (new_fd)
		put_files_struct(new_fd);

bad_unshare_cleanup_vm:
	if (new_mm)
		mmput(new_mm);

bad_unshare_cleanup_sigh:
	if (new_sigh)
		if (atomic_dec_and_test(&new_sigh->count))
			kmem_cache_free(sighand_cachep, new_sigh);

bad_unshare_cleanup_fs:
	if (new_fs)
		put_fs_struct(new_fs);

bad_unshare_cleanup_thread:
bad_unshare_out:
//.........这里部分代码省略.........

static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
{
	struct files_struct *files;
	struct task_struct *task;
	const struct cred *cred;
	struct inode *inode;
	int fd;

	if (flags & LOOKUP_RCU)
		return -ECHILD;

	inode = dentry->d_inode;
	task = get_proc_task(inode);
	fd = proc_fd(inode);

	if (task) {
		files = get_files_struct(task);
		if (files) {
			struct file *file;

			rcu_read_lock();
			file = fcheck_files(files, fd);
			if (file) {
				unsigned f_mode = file->f_mode;

				rcu_read_unlock();
				put_files_struct(files);

				if (task_dumpable(task)) {
					rcu_read_lock();
					cred = __task_cred(task);
					inode->i_uid = cred->euid;
					inode->i_gid = cred->egid;
					rcu_read_unlock();
				} else {
					inode->i_uid = GLOBAL_ROOT_UID;
					inode->i_gid = GLOBAL_ROOT_GID;
				}

				if (S_ISLNK(inode->i_mode)) {
					unsigned i_mode = S_IFLNK;
					if (f_mode & FMODE_READ)
						i_mode |= S_IRUSR | S_IXUSR;
					if (f_mode & FMODE_WRITE)
						i_mode |= S_IWUSR | S_IXUSR;
					inode->i_mode = i_mode;
				}

				security_task_to_inode(task, inode);
				put_task_struct(task);
				return 1;
			}
			rcu_read_unlock();
			put_files_struct(files);
		}
		put_task_struct(task);
	}

	d_drop(dentry);
	return 0;
}

static long
fd_link_ioctl (struct file *f, unsigned int ioctl, unsigned long arg)
{
	void __user *argp = (void __user *) arg;
	struct task_struct *task_target = NULL;
	struct file *file;
	struct files_struct *files;
	struct fdtable *fdt;
	struct fd_copy fd_copy;

	switch (ioctl)
	{
		case FD_COPY:
			if (copy_from_user (&fd_copy, argp, sizeof (struct fd_copy)))
				return -EFAULT;

			/*
			 * Find the task struct for the target pid
			 */
			task_target =
				pid_task (find_vpid (fd_copy.target_pid), PIDTYPE_PID);
			if (task_target == NULL)
			{
				printk (KERN_DEBUG "Failed to get mem ctx for target pid\n");
				return -EFAULT;
			}

			files = get_files_struct (current);
			if (files == NULL)
			{
				printk (KERN_DEBUG "Failed to get files struct\n");
				return -EFAULT;
			}

			rcu_read_lock ();
			file = fcheck_files (files, fd_copy.source_fd);
			if (file)
			{
				if (file->f_mode & FMODE_PATH
						|| !atomic_long_inc_not_zero (&file->f_count))
					file = NULL;
			}
			rcu_read_unlock ();
			put_files_struct (files);

			if (file == NULL)
			{
				printk (KERN_DEBUG "Failed to get file from source pid\n");
				return 0;
			}

			/*
			 * Release the existing fd in the source process
			 */
			spin_lock (&files->file_lock);
			filp_close (file, files);
			fdt = files_fdtable (files);
			fdt->fd[fd_copy.source_fd] = NULL;
			spin_unlock (&files->file_lock);

			/*
			 * Find the file struct associated with the target fd.
			 */

			files = get_files_struct (task_target);
			if (files == NULL)
			{
				printk (KERN_DEBUG "Failed to get files struct\n");
				return -EFAULT;
			}

			rcu_read_lock ();
			file = fcheck_files (files, fd_copy.target_fd);
			if (file)
			{
				if (file->f_mode & FMODE_PATH
						|| !atomic_long_inc_not_zero (&file->f_count))
					file = NULL;
			}
			rcu_read_unlock ();
			put_files_struct (files);

			if (file == NULL)
			{
				printk (KERN_DEBUG "Failed to get file from target pid\n");
				return 0;
			}


			/*
			 * Install the file struct from the target process into the
			 * file desciptor of the source process,
			 */

			fd_install (fd_copy.source_fd, file);

			return 0;

		default:
			return -ENOIOCTLCMD;
//.........这里部分代码省略.........