* Re: [PATCH] security: keys: add NULL checking for key->type->instantiate
2019-02-06 22:26 ` David Howells
@ 2019-02-26 9:09 ` Geliang Tang
2019-02-26 9:11 ` Geliang Tang
1 sibling, 0 replies; 4+ messages in thread
From: Geliang Tang @ 2019-02-26 9:09 UTC (permalink / raw)
To: David Howells, James Morris, Serge E. Hallyn
Cc: keyrings, linux-security-module, linux-kernel
On Wed, Feb 06, 2019 at 10:26:53PM +0000, David Howells wrote:
> Geliang Tang <geliangtang@gmail.com> wrote:
>
> > key->type->instantiate can be NULL, add NULL checking to prevent
> > NULL pointer dereference in __key_instantiate_and_link().
>
> Do you have an oops report or test case for this?
>
> David
Here is the test module code. Insmod it, we can get the oops.
#include <linux/init.h>
#include <linux/module.h>
#include <linux/key.h>
#include <linux/key-type.h>
#include <linux/cred.h>
#include <linux/seq_file.h>
static int test_instantiate(struct key *key, struct key_preparsed_payload *prep)
{
return 0;
}
static void test_describe(const struct key *key, struct seq_file *m)
{
seq_puts(m, key->description);
}
struct key_type test_key_type = {
.name = "test",
//.instantiate = test_instantiate,
.describe = test_describe,
};
static int __init test_init(void)
{
const struct cred *cred = current_cred();
struct key *key;
int ret;
register_key_type(&test_key_type);
key = key_alloc(&test_key_type, "test",
GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
KEY_POS_SEARCH, KEY_ALLOC_NOT_IN_QUOTA, NULL);
if (IS_ERR(key))
return -1;
pr_info("keyring allocated successfully.\n");
ret = key_instantiate_and_link(key,
NULL,
sizeof(int),
current->cred->user->session_keyring,
NULL);
if (ret < 0) {
key_revoke(key);
key_put(key);
return ret;
}
return 0;
}
static void __exit test_exit(void)
{
unregister_key_type(&test_key_type);
}
module_init(test_init);
module_exit(test_exit);
MODULE_LICENSE("GPL");
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] security: keys: add NULL checking for key->type->instantiate
2019-02-06 22:26 ` David Howells
2019-02-26 9:09 ` Geliang Tang
@ 2019-02-26 9:11 ` Geliang Tang
1 sibling, 0 replies; 4+ messages in thread
From: Geliang Tang @ 2019-02-26 9:11 UTC (permalink / raw)
To: David Howells, James Morris, Serge E. Hallyn
Cc: keyrings, linux-security-module, linux-kernel
On Wed, Feb 06, 2019 at 10:26:53PM +0000, David Howells wrote:
> Geliang Tang <geliangtang@gmail.com> wrote:
>
> > key->type->instantiate can be NULL, add NULL checking to prevent
> > NULL pointer dereference in __key_instantiate_and_link().
>
> Do you have an oops report or test case for this?
>
> David
Here is the test module code. Insmod it, we can get the oops.
#include <linux/init.h>
#include <linux/module.h>
#include <linux/key.h>
#include <linux/key-type.h>
#include <linux/cred.h>
#include <linux/seq_file.h>
static int test_instantiate(struct key *key, struct key_preparsed_payload *prep)
{
return 0;
}
static void test_describe(const struct key *key, struct seq_file *m)
{
seq_puts(m, key->description);
}
struct key_type test_key_type = {
.name = "test",
//.instantiate = test_instantiate,
.describe = test_describe,
};
static int __init test_init(void)
{
const struct cred *cred = current_cred();
struct key *key;
int ret;
register_key_type(&test_key_type);
key = key_alloc(&test_key_type, "test",
GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
KEY_POS_SEARCH, KEY_ALLOC_NOT_IN_QUOTA, NULL);
if (IS_ERR(key))
return -1;
pr_info("keyring allocated successfully.\n");
ret = key_instantiate_and_link(key,
NULL,
sizeof(int),
current->cred->user->session_keyring,
NULL);
if (ret < 0) {
key_revoke(key);
key_put(key);
return ret;
}
return 0;
}
static void __exit test_exit(void)
{
unregister_key_type(&test_key_type);
}
module_init(test_init);
module_exit(test_exit);
MODULE_LICENSE("GPL");
^ permalink raw reply [flat|nested] 4+ messages in thread