forked from luck/tmp_suning_uos_patched
073931017b
When file permissions are modified via chmod(2) and the user is not in the owning group or capable of CAP_FSETID, the setgid bit is cleared in inode_change_ok(). Setting a POSIX ACL via setxattr(2) sets the file permissions as well as the new ACL, but doesn't clear the setgid bit in a similar way; this allows to bypass the check in chmod(2). Fix that. References: CVE-2016-7097 Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
148 lines
3.2 KiB
C
148 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 && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
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return -E2BIG;
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if (type == ACL_TYPE_ACCESS) {
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umode_t mode = inode->i_mode;
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error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
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if (error)
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return error;
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if (mode != inode->i_mode)
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mark_inode_dirty(inode);
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}
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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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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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ret = __gfs2_set_acl(inode, acl, type);
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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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