49b60d4aa9
(cherry pick from commit 073931017b49d9458aa351605b43a7e34598caef)
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.
NB: We did not resolve the ACL leak in this CL, require additional
upstream fix.
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>
Bug: 32458736
Change-Id: I19591ad452cc825ac282b3cfd2daaa72aa9a1ac1
111 lines
2.3 KiB
C
111 lines
2.3 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 "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 GFS2_POSIX_ACL_ACCESS;
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case ACL_TYPE_DEFAULT:
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return GFS2_POSIX_ACL_DEFAULT;
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}
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return NULL;
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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 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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if (name == NULL)
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return ERR_PTR(-EINVAL);
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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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if (len == 0)
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return NULL;
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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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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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BUG_ON(name == NULL);
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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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