309e8cda59
When changing a file's acl mask, __gfs2_set_acl() will first set the group bits of i_mode to the value of the mask, and only then set the actual extended attribute representing the new acl. If the second part fails (due to lack of space, for example) and the file had no acl attribute to begin with, the system will from now on assume that the mask permission bits are actual group permission bits, potentially granting access to the wrong users. Prevent this by only changing the inode mode after the acl has been set. Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
152 lines
3.2 KiB
C
152 lines
3.2 KiB
C
/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License version 2.
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*/
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/completion.h>
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#include <linux/buffer_head.h>
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#include <linux/xattr.h>
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#include <linux/posix_acl.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/gfs2_ondisk.h>
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#include "gfs2.h"
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#include "incore.h"
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#include "acl.h"
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#include "xattr.h"
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#include "glock.h"
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#include "inode.h"
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#include "meta_io.h"
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#include "rgrp.h"
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#include "trans.h"
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#include "util.h"
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static const char *gfs2_acl_name(int type)
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{
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switch (type) {
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case ACL_TYPE_ACCESS:
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return XATTR_POSIX_ACL_ACCESS;
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case ACL_TYPE_DEFAULT:
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return XATTR_POSIX_ACL_DEFAULT;
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}
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return NULL;
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}
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static struct posix_acl *__gfs2_get_acl(struct inode *inode, int type)
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{
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struct gfs2_inode *ip = GFS2_I(inode);
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struct posix_acl *acl;
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const char *name;
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char *data;
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int len;
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if (!ip->i_eattr)
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return NULL;
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name = gfs2_acl_name(type);
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len = gfs2_xattr_acl_get(ip, name, &data);
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if (len <= 0)
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return ERR_PTR(len);
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acl = posix_acl_from_xattr(&init_user_ns, data, len);
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kfree(data);
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return acl;
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}
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struct posix_acl *gfs2_get_acl(struct inode *inode, int type)
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{
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struct gfs2_inode *ip = GFS2_I(inode);
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struct gfs2_holder gh;
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bool need_unlock = false;
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struct posix_acl *acl;
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if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
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int ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
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LM_FLAG_ANY, &gh);
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if (ret)
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return ERR_PTR(ret);
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need_unlock = true;
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}
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acl = __gfs2_get_acl(inode, type);
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if (need_unlock)
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gfs2_glock_dq_uninit(&gh);
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return acl;
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}
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int __gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
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{
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int error;
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int len;
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char *data;
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const char *name = gfs2_acl_name(type);
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if (acl) {
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len = posix_acl_to_xattr(&init_user_ns, acl, NULL, 0);
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if (len == 0)
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return 0;
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data = kmalloc(len, GFP_NOFS);
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if (data == NULL)
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return -ENOMEM;
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error = posix_acl_to_xattr(&init_user_ns, acl, data, len);
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if (error < 0)
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goto out;
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} else {
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data = NULL;
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len = 0;
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}
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error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
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if (error)
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goto out;
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set_cached_acl(inode, type, acl);
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out:
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kfree(data);
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return error;
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}
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int gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
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{
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struct gfs2_inode *ip = GFS2_I(inode);
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struct gfs2_holder gh;
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bool need_unlock = false;
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int ret;
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umode_t mode;
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if (acl && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
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return -E2BIG;
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ret = gfs2_rsqa_alloc(ip);
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if (ret)
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return ret;
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if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
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ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
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if (ret)
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return ret;
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need_unlock = true;
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}
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mode = inode->i_mode;
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if (type == ACL_TYPE_ACCESS && acl) {
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ret = posix_acl_update_mode(inode, &mode, &acl);
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if (ret)
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goto unlock;
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}
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ret = __gfs2_set_acl(inode, acl, type);
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if (!ret && mode != inode->i_mode) {
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inode->i_mode = mode;
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mark_inode_dirty(inode);
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}
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unlock:
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if (need_unlock)
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gfs2_glock_dq_uninit(&gh);
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return ret;
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}
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