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authorThomas Gleixner <tglx@linutronix.de>2009-08-20 06:05:01 -0400
committerThomas Gleixner <tglx@linutronix.de>2009-08-27 11:12:52 -0400
commitf4848472cd99487e182b64fb2a5d0e4fedbe86ad (patch)
treed407ce2579e01beca7bee81df5fa3dbfe99cc512 /arch/x86/kernel/x86_init.c
parent6b18ae3e2ff62daa9f181401759161dd8de0aadf (diff)
x86: Sanitize smp_record and move it to x86_init_ops
The x86 quirkification introduced an extra ugly hackery with a variable pointer in the mpparse code. If the pointer is initialized then it is dereferenced and the variable set to 0 or incremented. Create a x86_init_ops function and let the affected numaq code hold the function. Default init is a setup noop. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/x86_init.c')
-rw-r--r--arch/x86/kernel/x86_init.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index 1965bff3489c..83bd5db376ba 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -10,6 +10,7 @@
10#include <asm/e820.h> 10#include <asm/e820.h>
11 11
12void __cpuinit x86_init_noop(void) { } 12void __cpuinit x86_init_noop(void) { }
13void __init x86_init_uint_noop(unsigned int unused) { }
13 14
14/* 15/*
15 * The platform setup functions are preset with the default functions 16 * The platform setup functions are preset with the default functions
@@ -23,4 +24,8 @@ struct __initdata x86_init_ops x86_init = {
23 .reserve_ebda_region = reserve_ebda_region, 24 .reserve_ebda_region = reserve_ebda_region,
24 .memory_setup = default_machine_specific_memory_setup, 25 .memory_setup = default_machine_specific_memory_setup,
25 }, 26 },
27
28 .mpparse = {
29 .mpc_record = x86_init_uint_noop,
30 },
26}; 31};
/a> 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759
/*
  File: fs/xattr.c

  Extended attribute handling.

  Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
  Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
  Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
 */
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/xattr.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/security.h>
#include <linux/evm.h>
#include <linux/syscalls.h>
#include <linux/module.h>
#include <linux/fsnotify.h>
#include <linux/audit.h>
#include <asm/uaccess.h>


/*
 * Check permissions for extended attribute access.  This is a bit complicated
 * because different namespaces have very different rules.
 */
static int
xattr_permission(struct inode *inode, const char *name, int mask)
{
	/*
	 * We can never set or remove an extended attribute on a read-only
	 * filesystem  or on an immutable / append-only inode.
	 */
	if (mask & MAY_WRITE) {
		if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
			return -EPERM;
	}

	/*
	 * No restriction for security.* and system.* from the VFS.  Decision
	 * on these is left to the underlying filesystem / security module.
	 */
	if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) ||
	    !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
		return 0;

	/*
	 * The trusted.* namespace can only be accessed by privileged users.
	 */
	if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
		if (!capable(CAP_SYS_ADMIN))
			return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
		return 0;
	}

	/*
	 * In the user.* namespace, only regular files and directories can have
	 * extended attributes. For sticky directories, only the owner and
	 * privileged users can write attributes.
	 */
	if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
		if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
			return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
		if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) &&
		    (mask & MAY_WRITE) && !inode_owner_or_capable(inode))
			return -EPERM;
	}

	return inode_permission(inode, mask);
}

/**
 *  __vfs_setxattr_noperm - perform setxattr operation without performing
 *  permission checks.
 *
 *  @dentry - object to perform setxattr on
 *  @name - xattr name to set
 *  @value - value to set @name to
 *  @size - size of @value
 *  @flags - flags to pass into filesystem operations
 *
 *  returns the result of the internal setxattr or setsecurity operations.
 *
 *  This function requires the caller to lock the inode's i_mutex before it
 *  is executed. It also assumes that the caller will make the appropriate
 *  permission checks.
 */
int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
		const void *value, size_t size, int flags)
{
	struct inode *inode = dentry->d_inode;
	int error = -EOPNOTSUPP;
	int issec = !strncmp(name, XATTR_SECURITY_PREFIX,
				   XATTR_SECURITY_PREFIX_LEN);

	if (issec)
		inode->i_flags &= ~S_NOSEC;
	if (inode->i_op->setxattr) {
		error = inode->i_op->setxattr(dentry, name, value, size, flags);
		if (!error) {
			fsnotify_xattr(dentry);
			security_inode_post_setxattr(dentry, name, value,
						     size, flags);
		}
	} else if (issec) {
		const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
		error = security_inode_setsecurity(inode, suffix, value,
						   size, flags);
		if (!error)
			fsnotify_xattr(dentry);
	}

	return error;
}


int
vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
		size_t size, int flags)
{
	struct inode *inode = dentry->d_inode;
	int error;

	error = xattr_permission(inode, name, MAY_WRITE);
	if (error)
		return error;

	mutex_lock(&inode->i_mutex);
	error = security_inode_setxattr(dentry, name, value, size, flags);
	if (error)
		goto out;

	error = __vfs_setxattr_noperm(dentry, name, value, size, flags);

out:
	mutex_unlock(&inode->i_mutex);
	return error;
}
EXPORT_SYMBOL_GPL(vfs_setxattr);

ssize_t
xattr_getsecurity(struct inode *inode, const char *name, void *value,
			size_t size)
{
	void *buffer = NULL;
	ssize_t len;

	if (!value || !size) {
		len = security_inode_getsecurity(inode, name, &buffer, false);
		goto out_noalloc;
	}

	len = security_inode_getsecurity(inode, name, &buffer, true);
	if (len < 0)
		return len;
	if (size < len) {
		len = -ERANGE;
		goto out;
	}
	memcpy(value, buffer, len);
out:
	security_release_secctx(buffer, len);
out_noalloc:
	return len;
}
EXPORT_SYMBOL_GPL(xattr_getsecurity);

/*
 * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
 *
 * Allocate memory, if not already allocated, or re-allocate correct size,
 * before retrieving the extended attribute.
 *
 * Returns the result of alloc, if failed, or the getxattr operation.
 */
ssize_t
vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value,
		   size_t xattr_size, gfp_t flags)
{
	struct inode *inode = dentry->d_inode;
	char *value = *xattr_value;
	int error;

	error = xattr_permission(inode, name, MAY_READ);
	if (error)
		return error;

	if (!inode->i_op->getxattr)
		return -EOPNOTSUPP;

	error = inode->i_op->getxattr(dentry, name, NULL, 0);
	if (error < 0)
		return error;

	if (!value || (error > xattr_size)) {
		value = krealloc(*xattr_value, error + 1, flags);
		if (!value)
			return -ENOMEM;
		memset(value, 0, error + 1);
	}

	error = inode->i_op->getxattr(dentry, name, value, error);
	*xattr_value = value;
	return error;
}

/* Compare an extended attribute value with the given value */
int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name,
		  const char *value, size_t size, gfp_t flags)
{
	char *xattr_value = NULL;
	int rc;

	rc = vfs_getxattr_alloc(dentry, xattr_name, &xattr_value, 0, flags);
	if (rc < 0)
		return rc;

	if ((rc != size) || (memcmp(xattr_value, value, rc) != 0))
		rc = -EINVAL;
	else
		rc = 0;
	kfree(xattr_value);
	return rc;
}

ssize_t
vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
{
	struct inode *inode = dentry->d_inode;
	int error;

	error = xattr_permission(inode, name, MAY_READ);
	if (error)
		return error;

	error = security_inode_getxattr(dentry, name);
	if (error)
		return error;

	if (!strncmp(name, XATTR_SECURITY_PREFIX,
				XATTR_SECURITY_PREFIX_LEN)) {
		const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
		int ret = xattr_getsecurity(inode, suffix, value, size);
		/*
		 * Only overwrite the return value if a security module
		 * is actually active.
		 */
		if (ret == -EOPNOTSUPP)
			goto nolsm;
		return ret;
	}
nolsm:
	if (inode->i_op->getxattr)
		error = inode->i_op->getxattr(dentry, name, value, size);
	else
		error = -EOPNOTSUPP;

	return error;
}
EXPORT_SYMBOL_GPL(vfs_getxattr);

ssize_t
vfs_listxattr(struct dentry *d, char *list, size_t size)
{
	ssize_t error;

	error = security_inode_listxattr(d);
	if (error)
		return error;
	error = -EOPNOTSUPP;
	if (d->d_inode->i_op->listxattr) {
		error = d->d_inode->i_op->listxattr(d, list, size);
	} else {
		error = security_inode_listsecurity(d->d_inode, list, size);
		if (size && error > size)
			error = -ERANGE;
	}
	return error;
}
EXPORT_SYMBOL_GPL(vfs_listxattr);

int
vfs_removexattr(struct dentry *dentry, const char *name)
{
	struct inode *inode = dentry->d_inode;
	int error;

	if (!inode->i_op->removexattr)
		return -EOPNOTSUPP;

	error = xattr_permission(inode, name, MAY_WRITE);
	if (error)
		return error;

	error = security_inode_removexattr(dentry, name);
	if (error)
		return error;

	mutex_lock(&inode->i_mutex);
	error = inode->i_op->removexattr(dentry, name);
	mutex_unlock(&inode->i_mutex);

	if (!error) {
		fsnotify_xattr(dentry);
		evm_inode_post_removexattr(dentry, name);
	}
	return error;
}
EXPORT_SYMBOL_GPL(vfs_removexattr);


/*
 * Extended attribute SET operations
 */
static long
setxattr(struct dentry *d, const char __user *name, const void __user *value,
	 size_t size, int flags)
{
	int error;
	void *kvalue = NULL;
	char kname[XATTR_NAME_MAX + 1];

	if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
		return -EINVAL;

	error = strncpy_from_user(kname, name, sizeof(kname));
	if (error == 0 || error == sizeof(kname))
		error = -ERANGE;
	if (error < 0)
		return error;

	if (size) {
		if (size > XATTR_SIZE_MAX)
			return -E2BIG;
		kvalue = memdup_user(value, size);
		if (IS_ERR(kvalue))
			return PTR_ERR(kvalue);
	}

	error = vfs_setxattr(d, kname, kvalue, size, flags);
	kfree(kvalue);
	return error;
}

SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
		const char __user *, name, const void __user *, value,
		size_t, size, int, flags)
{
	struct path path;
	int error;

	error = user_path(pathname, &path);
	if (error)
		return error;
	error = mnt_want_write(path.mnt);
	if (!error) {
		error = setxattr(path.dentry, name, value, size, flags);
		mnt_drop_write(path.mnt);
	}
	path_put(&path);
	return error;
}

SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
		const char __user *, name, const void __user *, value,
		size_t, size, int, flags)
{
	struct path path;
	int error;

	error = user_lpath(pathname, &path);
	if (error)
		return error;
	error = mnt_want_write(path.mnt);
	if (!error) {
		error = setxattr(path.dentry, name, value, size, flags);
		mnt_drop_write(path.mnt);
	}
	path_put(&path);
	return error;
}

SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
		const void __user *,value, size_t, size, int, flags)
{
	struct file *f;
	struct dentry *dentry;
	int error = -EBADF;

	f = fget(fd);
	if (!f)
		return error;
	dentry = f->f_path.dentry;
	audit_inode(NULL, dentry);
	error = mnt_want_write_file(f);
	if (!error) {
		error = setxattr(dentry, name, value, size, flags);
		mnt_drop_write(f->f_path.mnt);
	}
	fput(f);
	return error;
}

/*
 * Extended attribute GET operations
 */
static ssize_t
getxattr(struct dentry *d, const char __user *name, void __user *value,
	 size_t size)
{
	ssize_t error;
	void *kvalue = NULL;
	char kname[XATTR_NAME_MAX + 1];

	error = strncpy_from_user(kname, name, sizeof(kname));
	if (error == 0 || error == sizeof(kname))
		error = -ERANGE;
	if (error < 0)
		return error;

	if (size) {
		if (size > XATTR_SIZE_MAX)
			size = XATTR_SIZE_MAX;
		kvalue = kzalloc(size, GFP_KERNEL);
		if (!kvalue)
			return -ENOMEM;
	}

	error = vfs_getxattr(d, kname, kvalue, size);
	if (error > 0) {
		if (size && copy_to_user(value, kvalue, error))
			error = -EFAULT;
	} else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
		/* The file system tried to returned a value bigger
		   than XATTR_SIZE_MAX bytes. Not possible. */
		error = -E2BIG;
	}
	kfree(kvalue);
	return error;
}

SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
		const char __user *, name, void __user *, value, size_t, size)
{
	struct path path;
	ssize_t error;

	error = user_path(pathname, &path);
	if (error)
		return error;
	error = getxattr(path.dentry, name, value, size);
	path_put(&path);
	return error;
}

SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
		const char __user *, name, void __user *, value, size_t, size)
{
	struct path path;
	ssize_t error;

	error = user_lpath(pathname, &path);
	if (error)
		return error;
	error = getxattr(path.dentry, name, value, size);
	path_put(&path);
	return error;
}

SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
		void __user *, value, size_t, size)
{
	struct file *f;
	ssize_t error = -EBADF;

	f = fget(fd);
	if (!f)
		return error;
	audit_inode(NULL, f->f_path.dentry);
	error = getxattr(f->f_path.dentry, name, value, size);
	fput(f);
	return error;
}

/*
 * Extended attribute LIST operations
 */
static ssize_t
listxattr(struct dentry *d, char __user *list, size_t size)
{
	ssize_t error;
	char *klist = NULL;

	if (size) {
		if (size > XATTR_LIST_MAX)
			size = XATTR_LIST_MAX;
		klist = kmalloc(size, GFP_KERNEL);
		if (!klist)
			return -ENOMEM;
	}

	error = vfs_listxattr(d, klist, size);
	if (error > 0) {
		if (size && copy_to_user(list, klist, error))
			error = -EFAULT;
	} else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
		/* The file system tried to returned a list bigger
		   than XATTR_LIST_MAX bytes. Not possible. */
		error = -E2BIG;
	}
	kfree(klist);
	return error;
}

SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
		size_t, size)
{
	struct path path;
	ssize_t error;

	error = user_path(pathname, &path);
	if (error)
		return error;
	error = listxattr(path.dentry, list, size);
	path_put(&path);
	return error;
}

SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
		size_t, size)
{
	struct path path;
	ssize_t error;

	error = user_lpath(pathname, &path);
	if (error)
		return error;
	error = listxattr(path.dentry, list, size);
	path_put(&path);
	return error;
}

SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
{
	struct file *f;
	ssize_t error = -EBADF;

	f = fget(fd);
	if (!f)
		return error;
	audit_inode(NULL, f->f_path.dentry);
	error = listxattr(f->f_path.dentry, list, size);
	fput(f);
	return error;
}

/*
 * Extended attribute REMOVE operations
 */
static long
removexattr(struct dentry *d, const char __user *name)
{
	int error;
	char kname[XATTR_NAME_MAX + 1];

	error = strncpy_from_user(kname, name, sizeof(kname));
	if (error == 0 || error == sizeof(kname))
		error = -ERANGE;
	if (error < 0)
		return error;

	return vfs_removexattr(d, kname);
}

SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
		const char __user *, name)
{
	struct path path;
	int error;

	error = user_path(pathname, &path);
	if (error)
		return error;
	error = mnt_want_write(path.mnt);
	if (!error) {
		error = removexattr(path.dentry, name);
		mnt_drop_write(path.mnt);
	}
	path_put(&path);
	return error;
}

SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
		const char __user *, name)
{
	struct path path;
	int error;

	error = user_lpath(pathname, &path);
	if (error)
		return error;
	error = mnt_want_write(path.mnt);
	if (!error) {
		error = removexattr(path.dentry, name);
		mnt_drop_write(path.mnt);
	}
	path_put(&path);
	return error;
}

SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
{
	struct file *f;
	struct dentry *dentry;
	int error = -EBADF;

	f = fget(fd);
	if (!f)
		return error;
	dentry = f->f_path.dentry;
	audit_inode(NULL, dentry);
	error = mnt_want_write_file(f);
	if (!error) {
		error = removexattr(dentry, name);
		mnt_drop_write(f->f_path.mnt);
	}
	fput(f);
	return error;
}


static const char *
strcmp_prefix(const char *a, const char *a_prefix)
{
	while (*a_prefix && *a == *a_prefix) {
		a++;
		a_prefix++;
	}
	return *a_prefix ? NULL : a;
}

/*
 * In order to implement different sets of xattr operations for each xattr
 * prefix with the generic xattr API, a filesystem should create a
 * null-terminated array of struct xattr_handler (one for each prefix) and
 * hang a pointer to it off of the s_xattr field of the superblock.
 *
 * The generic_fooxattr() functions will use this list to dispatch xattr
 * operations to the correct xattr_handler.
 */
#define for_each_xattr_handler(handlers, handler)		\
		for ((handler) = *(handlers)++;			\
			(handler) != NULL;			\
			(handler) = *(handlers)++)

/*
 * Find the xattr_handler with the matching prefix.
 */
static const struct xattr_handler *
xattr_resolve_name(const struct xattr_handler **handlers, const char **name)
{
	const struct xattr_handler *handler;

	if (!*name)
		return NULL;

	for_each_xattr_handler(handlers, handler) {
		const char *n = strcmp_prefix(*name, handler->prefix);
		if (n) {
			*name = n;
			break;
		}
	}
	return handler;
}

/*
 * Find the handler for the prefix and dispatch its get() operation.
 */
ssize_t
generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size)
{
	const struct xattr_handler *handler;

	handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
	if (!handler)
		return -EOPNOTSUPP;
	return handler->get(dentry, name, buffer, size, handler->flags);
}

/*
 * Combine the results of the list() operation from every xattr_handler in the
 * list.
 */
ssize_t
generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
{
	const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
	unsigned int size = 0;

	if (!buffer) {
		for_each_xattr_handler(handlers, handler) {
			size += handler->list(dentry, NULL, 0, NULL, 0,
					      handler->flags);
		}
	} else {
		char *buf = buffer;

		for_each_xattr_handler(handlers, handler) {
			size = handler->list(dentry, buf, buffer_size,
					     NULL, 0, handler->flags);
			if (size > buffer_size)
				return -ERANGE;
			buf += size;
			buffer_size -= size;
		}
		size = buf - buffer;
	}
	return size;
}

/*
 * Find the handler for the prefix and dispatch its set() operation.
 */
int
generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags)
{
	const struct xattr_handler *handler;

	if (size == 0)
		value = "";  /* empty EA, do not remove */
	handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
	if (!handler)
		return -EOPNOTSUPP;
	return handler->set(dentry, name, value, size, flags, handler->flags);
}

/*
 * Find the handler for the prefix and dispatch its set() operation to remove
 * any associated extended attribute.
 */
int
generic_removexattr(struct dentry *dentry, const char *name)
{
	const struct xattr_handler *handler;

	handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
	if (!handler)
		return -EOPNOTSUPP;
	return handler->set(dentry, name, NULL, 0,
			    XATTR_REPLACE, handler->flags);
}

EXPORT_SYMBOL(generic_getxattr);
EXPORT_SYMBOL(generic_listxattr);
EXPORT_SYMBOL(generic_setxattr);
EXPORT_SYMBOL(generic_removexattr);