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linux-next/net/ceph/auth_none.c
Tyler Hicks 2cb33cac62 libceph: Fix NULL pointer dereference in auth client code
A malicious monitor can craft an auth reply message that could cause a
NULL function pointer dereference in the client's kernel.

To prevent this, the auth_none protocol handler needs an empty
ceph_auth_client_ops->build_request() function.

CVE-2013-1059

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reported-by: Chanam Park <chanam.park@hkpco.kr>
Reviewed-by: Seth Arnold <seth.arnold@canonical.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Cc: stable@vger.kernel.org
2013-07-03 15:32:55 -07:00

138 lines
3.0 KiB
C

#include <linux/ceph/ceph_debug.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/ceph/decode.h>
#include <linux/ceph/auth.h>
#include "auth_none.h"
static void reset(struct ceph_auth_client *ac)
{
struct ceph_auth_none_info *xi = ac->private;
xi->starting = true;
xi->built_authorizer = false;
}
static void destroy(struct ceph_auth_client *ac)
{
kfree(ac->private);
ac->private = NULL;
}
static int is_authenticated(struct ceph_auth_client *ac)
{
struct ceph_auth_none_info *xi = ac->private;
return !xi->starting;
}
static int should_authenticate(struct ceph_auth_client *ac)
{
struct ceph_auth_none_info *xi = ac->private;
return xi->starting;
}
static int build_request(struct ceph_auth_client *ac, void *buf, void *end)
{
return 0;
}
/*
* the generic auth code decode the global_id, and we carry no actual
* authenticate state, so nothing happens here.
*/
static int handle_reply(struct ceph_auth_client *ac, int result,
void *buf, void *end)
{
struct ceph_auth_none_info *xi = ac->private;
xi->starting = false;
return result;
}
/*
* build an 'authorizer' with our entity_name and global_id. we can
* reuse a single static copy since it is identical for all services
* we connect to.
*/
static int ceph_auth_none_create_authorizer(
struct ceph_auth_client *ac, int peer_type,
struct ceph_auth_handshake *auth)
{
struct ceph_auth_none_info *ai = ac->private;
struct ceph_none_authorizer *au = &ai->au;
void *p, *end;
int ret;
if (!ai->built_authorizer) {
p = au->buf;
end = p + sizeof(au->buf);
ceph_encode_8(&p, 1);
ret = ceph_entity_name_encode(ac->name, &p, end - 8);
if (ret < 0)
goto bad;
ceph_decode_need(&p, end, sizeof(u64), bad2);
ceph_encode_64(&p, ac->global_id);
au->buf_len = p - (void *)au->buf;
ai->built_authorizer = true;
dout("built authorizer len %d\n", au->buf_len);
}
auth->authorizer = (struct ceph_authorizer *) au;
auth->authorizer_buf = au->buf;
auth->authorizer_buf_len = au->buf_len;
auth->authorizer_reply_buf = au->reply_buf;
auth->authorizer_reply_buf_len = sizeof (au->reply_buf);
return 0;
bad2:
ret = -ERANGE;
bad:
return ret;
}
static void ceph_auth_none_destroy_authorizer(struct ceph_auth_client *ac,
struct ceph_authorizer *a)
{
/* nothing to do */
}
static const struct ceph_auth_client_ops ceph_auth_none_ops = {
.name = "none",
.reset = reset,
.destroy = destroy,
.is_authenticated = is_authenticated,
.should_authenticate = should_authenticate,
.build_request = build_request,
.handle_reply = handle_reply,
.create_authorizer = ceph_auth_none_create_authorizer,
.destroy_authorizer = ceph_auth_none_destroy_authorizer,
};
int ceph_auth_none_init(struct ceph_auth_client *ac)
{
struct ceph_auth_none_info *xi;
dout("ceph_auth_none_init %p\n", ac);
xi = kzalloc(sizeof(*xi), GFP_NOFS);
if (!xi)
return -ENOMEM;
xi->starting = true;
xi->built_authorizer = false;
ac->protocol = CEPH_AUTH_NONE;
ac->private = xi;
ac->ops = &ceph_auth_none_ops;
return 0;
}