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/* auditfilter.c -- filtering of audit events
*
* Copyright 2003-2004 Red Hat, Inc.
* Copyright 2005 Hewlett-Packard Development Company, L.P.
* Copyright 2005 IBM Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include
<linux/kernel.h>
#include
<linux/audit.h>
#include
<linux/kthread.h>
#include
<linux/mutex.h>
#include
<linux/fs.h>
#include
<linux/namei.h>
#include
<linux/netlink.h>
#include
<linux/sched.h>
#include
<linux/slab.h>
#include
<linux/security.h>
#include
"audit.h"
/*
* Locking model:
*
* audit_filter_mutex:
* Synchronizes writes and blocking reads of audit's filterlist
* data. Rcu is used to traverse the filterlist and access
* contents of structs audit_entry, audit_watch and opaque
* LSM rules during filtering. If modified, these structures
* must be copied and replace their counterparts in the filterlist.
* An audit_parent struct is not accessed during filtering, so may
* be written directly provided audit_filter_mutex is held.
*/
/* Audit filter lists, defined in <linux/audit.h> */
struct
list_head
audit_filter_list
[
AUDIT_NR_FILTERS
]
=
{
LIST_HEAD_INIT
(
audit_filter_list
[
0
]),
LIST_HEAD_INIT
(
audit_filter_list
[
1
]),
LIST_HEAD_INIT
(
audit_filter_list
[
2
]),
LIST_HEAD_INIT
(
audit_filter_list
[
3
]),
LIST_HEAD_INIT
(
audit_filter_list
[
4
]),
LIST_HEAD_INIT
(
audit_filter_list
[
5
]),
#if
AUDIT_NR_FILTERS
!=
6
#error
Fix
audit_filter_list
initialiser
#endif
};
static
struct
list_head
audit_rules_list
[
AUDIT_NR_FILTERS
]
=
{
LIST_HEAD_INIT
(
audit_rules_list
[
0
]),
LIST_HEAD_INIT
(
audit_rules_list
[
1
]),
LIST_HEAD_INIT
(
audit_rules_list
[
2
]),
LIST_HEAD_INIT
(
audit_rules_list
[
3
]),
LIST_HEAD_INIT
(
audit_rules_list
[
4
]),
LIST_HEAD_INIT
(
audit_rules_list
[
5
]),
};
DEFINE_MUTEX
(
audit_filter_mutex
);
static
inline
void
audit_free_rule
(
struct
audit_entry
*
e
)
{
int
i
;
struct
audit_krule
*
erule
=
&
e
->
rule
;
/* some rules don't have associated watches */
if
(
erule
->
watch
)
audit_put_watch
(
erule
->
watch
);
if
(
erule
->
fields
)
for
(
i
=
0
;
i
<
erule
->
field_count
;
i
++
) {
struct
audit_field
*
f
=
&
erule
->
fields
[
i
];
kfree
(
f
->
lsm_str
);
security_audit_rule_free
(
f
->
lsm_rule
);
}
kfree
(
erule
->
fields
);
kfree
(
erule
->
filterkey
);
kfree
(
e
);
}
void
audit_free_rule_rcu
(
struct
rcu_head
*
head
)
{
struct
audit_entry
*
e
=
container_of
(
head
,
struct
audit_entry
,
rcu
);
audit_free_rule
(
e
);
}
/* Initialize an audit filterlist entry. */
static
inline
struct
audit_entry
*
audit_init_entry
(
u32
field_count
)
{
struct
audit_entry
*
entry
;
struct
audit_field
*
fields
;
entry
=
kzalloc
(
sizeof
(
*
entry
),
GFP_KERNEL
);
if
(
unlikely
(!
entry
))
return
NULL
;
fields
=
kzalloc
(
sizeof
(
*
fields
)
*
field_count
,
GFP_KERNEL
);
if
(
unlikely
(!
fields
)) {
kfree
(
entry
);
return
NULL
;
}
entry
->
rule
.
fields
=
fields
;
return
entry
;
}
/* Unpack a filter field's string representation from user-space
* buffer. */
char
*
audit_unpack_string
(
void
*
*
bufp
,
size_t
*
remain
,
size_t
len
)
{
char
*
str
;
if
(!
*
bufp
||
(
len
==
0
)
||
(
len
>
*
remain
))
return
ERR_PTR
(
-
EINVAL
);
/* Of the currently implemented string fields, PATH_MAX
* defines the longest valid length.
*/
if
(
len
>
PATH_MAX
)
return
ERR_PTR
(
-
ENAMETOOLONG
);
str
=
kmalloc
(
len
+
1
,
GFP_KERNEL
);
if
(
unlikely
(!
str
))
return
ERR_PTR
(
-
ENOMEM
);
memcpy
(
str
,
*
bufp
,
len
);
str
[
len
]
=
0
;
*
bufp
+=
len
;
*
remain
-=
len
;
return
str
;
}
/* Translate an inode field to kernel respresentation. */
static
inline
int
audit_to_inode
(
struct
audit_krule
*
krule
,
struct
audit_field
*
f
)
{
if
(
krule
->
listnr
!=
AUDIT_FILTER_EXIT
||
krule
->
watch
||
krule
->
inode_f
||
krule
->
tree
||
(
f
->
op
!=
Audit_equal
&&
f
->
op
!=
Audit_not_equal
))
return
-
EINVAL
;
krule
->
inode_f
=
f
;
return
0
;
}
static
__u32
*
classes
[
AUDIT_SYSCALL_CLASSES
];
int
__init
audit_register_class
(
int
class
,
unsigned
*
list
)
{
__u32
*
p
=
kzalloc
(
AUDIT_BITMASK_SIZE
*
sizeof
(
__u32
),
GFP_KERNEL
);
if
(!
p
)
return
-
ENOMEM
;
while
(
*
list
!=
~
0U
) {
unsigned
n
=
*
list
++
;
if
(
n
>=
AUDIT_BITMASK_SIZE
*
32
-
AUDIT_SYSCALL_CLASSES
) {
kfree
(
p
);
return
-
EINVAL
;
}
p
[
AUDIT_WORD
(
n
)] |=
AUDIT_BIT
(
n
);
}
if
(
class
>=
AUDIT_SYSCALL_CLASSES
||
classes
[
class
]) {
kfree
(
p
);
return
-
EINVAL
;
}
classes
[
class
]
=
p
;
return
0
;
}
int
audit_match_class
(
int
class
,
unsigned
syscall
)
{
if
(
unlikely
(
syscall
>=
AUDIT_BITMASK_SIZE
*
32
))
return
0
;
if
(
unlikely
(
class
>=
AUDIT_SYSCALL_CLASSES
||
!
classes
[
class
]))
return
0
;
return
classes
[
class
][
AUDIT_WORD
(
syscall
)]
&
AUDIT_BIT
(
syscall
);
}
#ifdef
CONFIG_AUDITSYSCALL
static
inline
int
audit_match_class_bits
(
int
class
,
u32
*
mask
)
{
int
i
;
if
(
classes
[
class
]) {
for
(
i
=
0
;
i
<
AUDIT_BITMASK_SIZE
;
i
++
)
if
(
mask
[
i
]
&
classes
[
class
][
i
])
return
0
;
}
return
1
;
}
static
int
audit_match_signal
(
struct
audit_entry
*
entry
)
{
struct
audit_field
*
arch
=
entry
->
rule
.
arch_f
;
if
(!
arch
) {
/* When arch is unspecified, we must check both masks on biarch
* as syscall number alone is ambiguous. */
return
(
audit_match_class_bits
(
AUDIT_CLASS_SIGNAL
,
entry
->
rule
.
mask
)
&&
audit_match_class_bits
(
AUDIT_CLASS_SIGNAL_32
,
entry
->
rule
.
mask
));
}
switch
(
audit_classify_arch
(
arch
->
val
)) {
case
0
:
/* native */
return
(
audit_match_class_bits
(
AUDIT_CLASS_SIGNAL
,
entry
->
rule
.
mask
));
case
1
:
/* 32bit on biarch */
return
(
audit_match_class_bits
(
AUDIT_CLASS_SIGNAL_32
,
entry
->
rule
.
mask
));
default
:
return
1
;
}
}
#endif
/* Common user-space to kernel rule translation. */
static
inline
struct
audit_entry
*
audit_to_entry_common
(
struct
audit_rule
*
rule
)
{
unsigned
listnr
;
struct
audit_entry
*
entry
;
int
i
,
err
;
err
=
-
EINVAL
;
listnr
=
rule
->
flags
&
~
AUDIT_FILTER_PREPEND
;
switch
(
listnr
) {
default
:
goto
exit_err
;
case
AUDIT_FILTER_USER
:
case
AUDIT_FILTER_TYPE
:
#ifdef
CONFIG_AUDITSYSCALL
case
AUDIT_FILTER_ENTRY
:
case
AUDIT_FILTER_EXIT
:
case
AUDIT_FILTER_TASK
:
#endif
;
}
if
(
unlikely
(
rule
->
action
==
AUDIT_POSSIBLE
)) {
printk
(
KERN_ERR
"AUDIT_POSSIBLE is deprecated\n"
);
goto
exit_err
;
}
if
(
rule
->
action
!=
AUDIT_NEVER
&&
rule
->
action
!=
AUDIT_ALWAYS
)
goto
exit_err
;
if
(
rule
->
field_count
>
AUDIT_MAX_FIELDS
)
goto
exit_err
;
err
=
-
ENOMEM
;
entry
=
audit_init_entry
(
rule
->
field_count
);
if
(!
entry
)
goto
exit_err
;
entry
->
rule
.
flags
=
rule
->
flags
&
AUDIT_FILTER_PREPEND
;
entry
->
rule
.
listnr
=
listnr
;
entry
->
rule
.
action
=
rule
->
action
;
entry
->
rule
.
field_count
=
rule
->
field_count
;
for
(
i
=
0
;
i
<
AUDIT_BITMASK_SIZE
;
i
++
)
entry
->
rule
.
mask
[
i
]
=
rule
->
mask
[
i
];
for
(
i
=
0
;
i
<
AUDIT_SYSCALL_CLASSES
;
i
++
) {
int
bit
=
AUDIT_BITMASK_SIZE
*
32
-
i
-
1
;
__u32
*
p
=
&
entry
->
rule
.
mask
[
AUDIT_WORD
(
bit
)];
__u32
*
class
;
if
(!(
*
p
&
AUDIT_BIT
(
bit
)))
continue
;
*
p
&= ~
AUDIT_BIT
(
bit
);
class
=
classes
[
i
];
if
(
class
) {
int
j
;
for
(
j
=
0
;
j
<
AUDIT_BITMASK_SIZE
;
j
++
)
entry
->
rule
.
mask
[
j
] |=
class
[
j
];
}
}
return
entry
;
exit_err
:
return
ERR_PTR
(
err
);
}
static
u32
audit_ops
[]
=
{
[
Audit_equal
]
=
AUDIT_EQUAL
,
[
Audit_not_equal
]
=
AUDIT_NOT_EQUAL
,
[
Audit_bitmask
]
=
AUDIT_BIT_MASK
,
[
Audit_bittest
]
=
AUDIT_BIT_TEST
,
[
Audit_lt
]
=
AUDIT_LESS_THAN
,
[
Audit_gt
]
=
AUDIT_GREATER_THAN
,
[
Audit_le
]
=
AUDIT_LESS_THAN_OR_EQUAL
,
[
Audit_ge
]
=
AUDIT_GREATER_THAN_OR_EQUAL
,
};
static
u32
audit_to_op
(
u32
op
)
{
u32
n
;
for
(
n
=
Audit_equal
;
n
<
Audit_bad
&&
audit_ops
[
n
]
!=
op
;
n
++
)
;
return
n
;
}
/* Translate struct audit_rule to kernel's rule respresentation.
* Exists for backward compatibility with userspace. */
static
struct
audit_entry
*
audit_rule_to_entry
(
struct
audit_rule
*
rule
)
{
struct
audit_entry
*
entry
;
int
err
=
0
;
int
i
;
entry
=
audit_to_entry_common
(
rule
);
if
(
IS_ERR
(
entry
))
goto
exit_nofree
;
for
(
i
=
0
;
i
<
rule
->
field_count
;
i
++
) {
struct
audit_field
*
f
=
&
entry
->
rule
.
fields
[
i
];
u32
n
;
n
=
rule
->
fields
[
i
]
&
(
AUDIT_NEGATE
|
AUDIT_OPERATORS
);
/* Support for legacy operators where
* AUDIT_NEGATE bit signifies != and otherwise assumes == */
if
(
n
&
AUDIT_NEGATE
)
f
->
op
=
Audit_not_equal
;
else
if
(!
n
)
f
->
op
=
Audit_equal
;
else
f
->
op
=
audit_to_op
(
n
);
entry
->
rule
.
vers_ops
=
(
n
&
AUDIT_OPERATORS
) ?
2
:
1
;
f
->
type
=
rule
->
fields
[
i
]
&
~(
AUDIT_NEGATE
|
AUDIT_OPERATORS
);
f
->
val
=
rule
->
values
[
i
];
err
=
-
EINVAL
;
if
(
f
->
op
==
Audit_bad
)
goto
exit_free
;
switch
(
f
->
type
) {
default
:
goto
exit_free
;
case
AUDIT_PID
:
case
AUDIT_UID
:
case
AUDIT_EUID
:
case
AUDIT_SUID
:
case
AUDIT_FSUID
:
case
AUDIT_GID
:
case
AUDIT_EGID
:
case
AUDIT_SGID
:
case
AUDIT_FSGID
:
case
AUDIT_LOGINUID
:
case
AUDIT_PERS
:
case
AUDIT_MSGTYPE
:
case
AUDIT_PPID
:
case
AUDIT_DEVMAJOR
:
case
AUDIT_DEVMINOR
:
case
AUDIT_EXIT
:
case
AUDIT_SUCCESS
:
/* bit ops are only useful on syscall args */
if
(
f
->
op
==
Audit_bitmask
||
f
->
op
==
Audit_bittest
)
goto
exit_free
;
break
;
case
AUDIT_ARG0
:
case
AUDIT_ARG1
:
case
AUDIT_ARG2
:
case
AUDIT_ARG3
:
break
;
/* arch is only allowed to be = or != */
case
AUDIT_ARCH
:
if
(
f
->
op
!=
Audit_not_equal
&&
f
->
op
!=
Audit_equal
)
goto
exit_free
;
entry
->
rule
.
arch_f
=
f
;
break
;
case
AUDIT_PERM
:
if
(
f
->
val
&
~
15
)
goto
exit_free
;
break
;
case
AUDIT_FILETYPE
:
if
((
f
->
val
&
~
S_IFMT
)
>
S_IFMT
)
goto
exit_free
;
break
;
case
AUDIT_INODE
:
err
=
audit_to_inode
(
&
entry
->
rule
,
f
);
if
(
err
)
goto
exit_free
;
break
;
}
}
if
(
entry
->
rule
.
inode_f
&&
entry
->
rule
.
inode_f
->
op
==
Audit_not_equal
)
entry
->
rule
.
inode_f
=
NULL
;
exit_nofree
:
return
entry
;
exit_free
:
audit_free_rule
(
entry
);
return
ERR_PTR
(
err
);
}
/* Translate struct audit_rule_data to kernel's rule respresentation. */
static
struct
audit_entry
*
audit_data_to_entry
(
struct
audit_rule_data
*
data
,
size_t
datasz
)
{
int
err
=
0
;
struct
audit_entry
*
entry
;
void
*
bufp
;
size_t
remain
=
datasz
-
sizeof
(
struct
audit_rule_data
);
int
i
;
char
*
str
;
entry
=
audit_to_entry_common
((
struct
audit_rule
*
)
data
);
if
(
IS_ERR
(
entry
))
goto
exit_nofree
;
bufp
=
data
->
buf
;
entry
->
rule
.
vers_ops
=
2
;
for
(
i
=
0
;
i
<
data
->
field_count
;
i
++
) {
struct
audit_field
*
f
=
&
entry
->
rule
.
fields
[
i
];
err
=
-
EINVAL
;
f
->
op
=
audit_to_op
(
data
->
fieldflags
[
i
]);
if
(
f
->
op
==
Audit_bad
)
goto
exit_free
;
f
->
type
=
data
->
fields
[
i
];
f
->
val
=
data
->
values
[
i
];
f
->
lsm_str
=
NULL
;
f
->
lsm_rule
=
NULL
;
switch
(
f
->
type
) {
case
AUDIT_PID
:
case
AUDIT_UID
:
case
AUDIT_EUID
:
case
AUDIT_SUID
:
case
AUDIT_FSUID
:
case
AUDIT_GID
:
case
AUDIT_EGID
:
case
AUDIT_SGID
:
case
AUDIT_FSGID
:
case
AUDIT_LOGINUID
:
case
AUDIT_PERS
:
case
AUDIT_MSGTYPE
:
case
AUDIT_PPID
:
case
AUDIT_DEVMAJOR
:
case
AUDIT_DEVMINOR
:
case
AUDIT_EXIT
:
case
AUDIT_SUCCESS
:
case
AUDIT_ARG0
:
case
AUDIT_ARG1
:
case
AUDIT_ARG2
:
case
AUDIT_ARG3
:
break
;
case
AUDIT_ARCH
:
entry
->
rule
.
arch_f
=
f
;
break
;
case
AUDIT_SUBJ_USER
:
case
AUDIT_SUBJ_ROLE
:
case
AUDIT_SUBJ_TYPE
:
case
AUDIT_SUBJ_SEN
:
case
AUDIT_SUBJ_CLR
:
case
AUDIT_OBJ_USER
:
case
AUDIT_OBJ_ROLE
:
case
AUDIT_OBJ_TYPE
:
case
AUDIT_OBJ_LEV_LOW
:
case
AUDIT_OBJ_LEV_HIGH
:
str
=
audit_unpack_string
(
&
bufp
,
&
remain
,
f
->
val
);
if
(
IS_ERR
(
str
))
goto
exit_free
;
entry
->
rule
.
buflen
+=
f
->
val
;
err
=
security_audit_rule_init
(
f
->
type
,
f
->
op
,
str
,
(
void
*
*
)
&
f
->
lsm_rule
);
/* Keep currently invalid fields around in case they
* become valid after a policy reload. */
if
(
err
==
-
EINVAL
) {
printk
(
KERN_WARNING
"audit rule for LSM "
"\'%s\' is invalid\n"
,
str
);
err
=
0
;
}
if
(
err
) {
kfree
(
str
);
goto
exit_free
;
}
else
f
->
lsm_str
=
str
;
break
;
case
AUDIT_WATCH
:
str
=
audit_unpack_string
(
&
bufp
,
&
remain
,
f
->
val
);
if
(
IS_ERR
(
str
))
goto
exit_free
;
entry
->
rule
.
buflen
+=
f
->
val
;
err
=
audit_to_watch
(
&
entry
->
rule
,
str
,
f
->
val
,
f
->
op
);
if
(
err
) {
kfree
(
str
);
goto
exit_free
;
}
break
;
case
AUDIT_DIR
:
str
=
audit_unpack_string
(
&
bufp
,
&
remain
,
f
->
val
);
if
(
IS_ERR
(
str
))
goto
exit_free
;
entry
->
rule
.
buflen
+=
f
->
val
;
err
=
audit_make_tree
(
&
entry
->
rule
,
str
,
f
->
op
);
kfree
(
str
);
if
(
err
)
goto
exit_free
;
break
;
case
AUDIT_INODE
:
err
=
audit_to_inode
(
&
entry
->
rule
,
f
);
if
(
err
)
goto
exit_free
;
break
;
case
AUDIT_FILTERKEY
:
err
=
-
EINVAL
;
if
(
entry
->
rule
.
filterkey
||
f
->
val
>
AUDIT_MAX_KEY_LEN
)
goto
exit_free
;
str
=
audit_unpack_string
(
&
bufp
,
&
remain
,
f
->
val
);
if
(
IS_ERR
(
str
))
goto
exit_free
;
entry
->
rule
.
buflen
+=
f
->
val
;
entry
->
rule
.
filterkey
=
str
;
break
;
case
AUDIT_PERM
:
if
(
f
->
val
&
~
15
)
goto
exit_free
;
break
;
case
AUDIT_FILETYPE
:
if
((
f
->
val
&
~
S_IFMT
)
>
S_IFMT
)
goto
exit_free
;
break
;
default
:
goto
exit_free
;
}
}
if
(
entry
->
rule
.
inode_f
&&
entry
->
rule
.
inode_f
->
op
==
Audit_not_equal
)
entry
->
rule
.
inode_f
=
NULL
;
exit_nofree
:
return
entry
;
exit_free
:
audit_free_rule
(
entry
);
return
ERR_PTR
(
err
);
}
/* Pack a filter field's string representation into data block. */
static
inline
size_t
audit_pack_string
(
void
*
*
bufp
,
const
char
*
str
)
{
size_t
len
=
strlen
(
str
);
memcpy
(
*
bufp
,
str
,
len
);
*
bufp
+=
len
;
return
len
;
}
/* Translate kernel rule respresentation to struct audit_rule.
* Exists for backward compatibility with userspace. */
static
struct
audit_rule
*
audit_krule_to_rule
(
struct
audit_krule
*
krule
)
{
struct
audit_rule
*
rule
;
int
i
;
rule
=
kzalloc
(
sizeof
(
*
rule
),
GFP_KERNEL
);
if
(
unlikely
(!
rule
))
return
NULL
;
rule
->
flags
=
krule
->
flags
|
krule
->
listnr
;
rule
->
action
=
krule
->
action
;
rule
->
field_count
=
krule
->
field_count
;
for
(
i
=
0
;
i
<
rule
->
field_count
;
i
++
) {
rule
->
values
[
i
]
=
krule
->
fields
[
i
].
val
;
rule
->
fields
[
i
]
=
krule
->
fields
[
i
].
type
;
if
(
krule
->
vers_ops
==
1
) {
if
(
krule
->
fields
[
i
].
op
==
Audit_not_equal
)
rule
->
fields
[
i
] |=
AUDIT_NEGATE
;
}
else
{
rule
->
fields
[
i
] |=
audit_ops
[
krule
->
fields
[
i
].
op
];
}
}
for
(
i
=
0
;
i
<
AUDIT_BITMASK_SIZE
;
i
++
)
rule
->
mask
[
i
]
=
krule
->
mask
[
i
];
return
rule
;
}
/* Translate kernel rule respresentation to struct audit_rule_data. */
static
struct
audit_rule_data
*
audit_krule_to_data
(
struct
audit_krule
*
krule
)
{
struct
audit_rule_data
*
data
;
void
*
bufp
;
int
i
;
data
=
kmalloc
(
sizeof
(
*
data
)
+
krule
->
buflen
,
GFP_KERNEL
);
if
(
unlikely
(!
data
))
return
NULL
;
memset
(
data
,
0
,
sizeof
(
*
data
));
data
->
flags
=
krule
->
flags
|
krule
->
listnr
;
data
->
action
=
krule
->
action
;
data
->
field_count
=
krule
->
field_count
;
bufp
=
data
->
buf
;
for
(
i
=
0
;
i
<
data
->
field_count
;
i
++
) {
struct
audit_field
*
f
=
&
krule
->
fields
[
i
];
data
->
fields
[
i
]
=
f
->
type
;
data
->
fieldflags
[
i
]
=
audit_ops
[
f
->
op
];
switch
(
f
->
type
) {
case
AUDIT_SUBJ_USER
:
case
AUDIT_SUBJ_ROLE
:
case
AUDIT_SUBJ_TYPE
:
case
AUDIT_SUBJ_SEN
:
case
AUDIT_SUBJ_CLR
:
case
AUDIT_OBJ_USER
:
case
AUDIT_OBJ_ROLE
:
case
AUDIT_OBJ_TYPE
:
case
AUDIT_OBJ_LEV_LOW
:
case
AUDIT_OBJ_LEV_HIGH
:
data
->
buflen
+=
data
->
values
[
i
]
=
audit_pack_string
(
&
bufp
,
f
->
lsm_str
);
break
;
case
AUDIT_WATCH
:
data
->
buflen
+=
data
->
values
[
i
]
=
audit_pack_string
(
&
bufp
,
audit_watch_path
(
krule
->
watch
));
break
;
case
AUDIT_DIR
:
data
->
buflen
+=
data
->
values
[
i
]
=
audit_pack_string
(
&
bufp
,
audit_tree_path
(
krule
->
tree
));
break
;
case
AUDIT_FILTERKEY
:
data
->
buflen
+=
data
->
values
[
i
]
=
audit_pack_string
(
&
bufp
,
krule
->
filterkey
);
break
;
default
:
data
->
values
[
i
]
=
f
->
val
;
}
}
for
(
i
=
0
;
i
<
AUDIT_BITMASK_SIZE
;
i
++
)
data
->
mask
[
i
]
=
krule
->
mask
[
i
];
return
data
;
}
/* Compare two rules in kernel format. Considered success if rules
* don't match. */
static
int
audit_compare_rule
(
struct
audit_krule
*
a
,
struct
audit_krule
*
b
)
{
int
i
;
if
(
a
->
flags
!=
b
->
flags
||
a
->
listnr
!=
b
->
listnr
||
a
->
action
!=
b
->
action
||
a
->
field_count
!=
b
->
field_count
)
return
1
;
for
(
i
=
0
;
i
<
a
->
field_count
;
i
++
) {
if
(
a
->
fields
[
i
].
type
!=
b
->
fields
[
i
].
type
||
a
->
fields
[
i
].
op
!=
b
->
fields
[
i
].
op
)
return
1
;
switch
(
a
->
fields
[
i
].
type
) {
case
AUDIT_SUBJ_USER
:
case
AUDIT_SUBJ_ROLE
:
case
AUDIT_SUBJ_TYPE
:
case
AUDIT_SUBJ_SEN
:
case
AUDIT_SUBJ_CLR
:
case
AUDIT_OBJ_USER
:
case
AUDIT_OBJ_ROLE
:
case
AUDIT_OBJ_TYPE
:
case
AUDIT_OBJ_LEV_LOW
:
case
AUDIT_OBJ_LEV_HIGH
:
if
(
strcmp
(
a
->
fields
[
i
].
lsm_str
,
b
->
fields
[
i
].
lsm_str
))
return
1
;
break
;
case
AUDIT_WATCH
:
if
(
strcmp
(
audit_watch_path
(
a
->
watch
),
audit_watch_path
(
b
->
watch
)))
return
1
;
break
;
case
AUDIT_DIR
:
if
(
strcmp
(
audit_tree_path
(
a
->
tree
),
audit_tree_path
(
b
->
tree
)))
return
1
;
break
;
case
AUDIT_FILTERKEY
:
/* both filterkeys exist based on above type compare */
if
(
strcmp
(
a
->
filterkey
,
b
->
filterkey
))
return
1
;
break
;
default
:
if
(
a
->
fields
[
i
].
val
!=
b
->
fields
[
i
].
val
)
return
1
;
}
}
for
(
i
=
0
;
i
<
AUDIT_BITMASK_SIZE
;
i
++
)
if
(
a
->
mask
[
i
]
!=
b
->
mask
[
i
])
return
1
;
return
0
;
}
/* Duplicate LSM field information. The lsm_rule is opaque, so must be
* re-initialized. */
static
inline
int
audit_dupe_lsm_field
(
struct
audit_field
*
df
,
struct
audit_field
*
sf
)
{
int
ret
=
0
;
char
*
lsm_str
;
/* our own copy of lsm_str */
lsm_str
=
kstrdup
(
sf
->
lsm_str
,
GFP_KERNEL
);
if
(
unlikely
(!
lsm_str
))
return
-
ENOMEM
;
df
->
lsm_str
=
lsm_str
;
/* our own (refreshed) copy of lsm_rule */
ret
=
security_audit_rule_init
(
df
->
type
,
df
->
op
,
df
->
lsm_str
,
(
void
*
*
)
&
df
->
lsm_rule
);
/* Keep currently invalid fields around in case they
* become valid after a policy reload. */
if
(
ret
==
-
EINVAL
) {
printk
(
KERN_WARNING
"audit rule for LSM \'%s\' is "
"invalid\n"
,
df
->
lsm_str
);
ret
=
0
;
}
return
ret
;
}
/* Duplicate an audit rule. This will be a deep copy with the exception
* of the watch - that pointer is carried over. The LSM specific fields
* will be updated in the copy. The point is to be able to replace the old
* rule with the new rule in the filterlist, then free the old rule.
* The rlist element is undefined; list manipulations are handled apart from
* the initial copy. */
struct
audit_entry
*
audit_dupe_rule
(
struct
audit_krule
*
old
)
{
u32
fcount
=
old
->
field_count
;
struct
audit_entry
*
entry
;
struct
audit_krule
*
new
;
char
*
fk
;
int
i
,
err
=
0
;
entry
=
audit_init_entry
(
fcount
);
if
(
unlikely
(!
entry
))
return
ERR_PTR
(
-
ENOMEM
);
new
=
&
entry
->
rule
;
new
->
vers_ops
=
old
->
vers_ops
;
new
->
flags
=
old
->
flags
;
new
->
listnr
=
old
->
listnr
;
new
->
action
=
old
->
action
;
for
(
i
=
0
;
i
<
AUDIT_BITMASK_SIZE
;
i
++
)
new
->
mask
[
i
]
=
old
->
mask
[
i
];
new
->
prio
=
old
->
prio
;
new
->
buflen
=
old
->
buflen
;
new
->
inode_f
=
old
->
inode_f
;
new
->
field_count
=
old
->
field_count
;
/*
* note that we are OK with not refcounting here; audit_match_tree()
* never dereferences tree and we can't get false positives there
* since we'd have to have rule gone from the list *and* removed
* before the chunks found by lookup had been allocated, i.e. before
* the beginning of list scan.
*/
new
->
tree
=
old
->
tree
;
memcpy
(
new
->
fields
,
old
->
fields
,
sizeof
(
struct
audit_field
)
*
fcount
);
/* deep copy this information, updating the lsm_rule fields, because
* the originals will all be freed when the old rule is freed. */
for
(
i
=
0
;
i
<
fcount
;
i
++
) {
switch
(
new
->
fields
[
i
].
type
) {
case
AUDIT_SUBJ_USER
:
case
AUDIT_SUBJ_ROLE
:
case
AUDIT_SUBJ_TYPE
:
case
AUDIT_SUBJ_SEN
:
case
AUDIT_SUBJ_CLR
:
case
AUDIT_OBJ_USER
:
case
AUDIT_OBJ_ROLE
:
case
AUDIT_OBJ_TYPE
:
case
AUDIT_OBJ_LEV_LOW
:
case
AUDIT_OBJ_LEV_HIGH
:
err
=
audit_dupe_lsm_field
(
&
new
->
fields
[
i
],
&
old
->
fields
[
i
]);
break
;
case
AUDIT_FILTERKEY
:
fk
=
kstrdup
(
old
->
filterkey
,
GFP_KERNEL
);
if
(
unlikely
(!
fk
))
err
=
-
ENOMEM
;
else
new
->
filterkey
=
fk
;
}
if
(
err
) {
audit_free_rule
(
entry
);
return
ERR_PTR
(
err
);
}
}
if
(
old
->
watch
) {
audit_get_watch
(
old
->
watch
);
new
->
watch
=
old
->
watch
;
}
return
entry
;
}
/* Find an existing audit rule.
* Caller must hold audit_filter_mutex to prevent stale rule data. */
static
struct
audit_entry
*
audit_find_rule
(
struct
audit_entry
*
entry
,
struct
list_head
*
*
p
)
{
struct
audit_entry
*
e
,
*
found
=
NULL
;
struct
list_head
*
list
;
int
h
;
if
(
entry
->
rule
.
inode_f
) {
h
=
audit_hash_ino
(
entry
->
rule
.
inode_f
->
val
);
*
p
=
list
=
&
audit_inode_hash
[
h
];
}
else
if
(
entry
->
rule
.
watch
) {
/* we don't know the inode number, so must walk entire hash */
for
(
h
=
0
;
h
<
AUDIT_INODE_BUCKETS
;
h
++
) {
list
=
&
audit_inode_hash
[
h
];
list_for_each_entry
(
e
,
list
,
list
)
if
(!
audit_compare_rule
(
&
entry
->
rule
,
&
e
->
rule
)) {
found
=
e
;
goto
out
;
}
}
goto
out
;
}
else
{
*
p
=
list
=
&
audit_filter_list
[
entry
->
rule
.
listnr
];
}
list_for_each_entry
(
e
,
list
,
list
)
if
(!
audit_compare_rule
(
&
entry
->
rule
,
&
e
->
rule
)) {
found
=
e
;
goto
out
;
}
out
:
return
found
;
}
static
u64
prio_low
=
~
0ULL
/
2
;
static
u64
prio_high
=
~
0ULL
/
2
-
1
;
/* Add rule to given filterlist if not a duplicate. */
static
inline
int
audit_add_rule
(
struct
audit_entry
*
entry
)
{
struct
audit_entry
*
e
;
struct
audit_watch
*
watch
=
entry
->
rule
.
watch
;
struct
audit_tree
*
tree
=
entry
->
rule
.
tree
;
struct
list_head
*
list
;
int
err
;
#ifdef
CONFIG_AUDITSYSCALL
int
dont_count
=
0
;
/* If either of these, don't count towards total */
if
(
entry
->
rule
.
listnr
==
AUDIT_FILTER_USER
||
entry
->
rule
.
listnr
==
AUDIT_FILTER_TYPE
)
dont_count
=
1
;
#endif
mutex_lock
(
&
audit_filter_mutex
);
e
=
audit_find_rule
(
entry
,
&
list
);
if
(
e
) {
mutex_unlock
(
&
audit_filter_mutex
);
err
=
-
EEXIST
;
/* normally audit_add_tree_rule() will free it on failure */
if
(
tree
)
audit_put_tree
(
tree
);
goto
error
;
}
if
(
watch
) {
/* audit_filter_mutex is dropped and re-taken during this call */
err
=
audit_add_watch
(
&
entry
->
rule
,
&
list
);
if
(
err
) {
mutex_unlock
(
&
audit_filter_mutex
);
goto
error
;
}
}
if
(
tree
) {
err
=
audit_add_tree_rule
(
&
entry
->
rule
);
if
(
err
) {
mutex_unlock
(
&
audit_filter_mutex
);
goto
error
;
}
}
entry
->
rule
.
prio
=
~
0ULL
;
if
(
entry
->
rule
.
listnr
==
AUDIT_FILTER_EXIT
) {
if
(
entry
->
rule
.
flags
&
AUDIT_FILTER_PREPEND
)
entry
->
rule
.
prio
=
++
prio_high
;
else
entry
->
rule
.
prio
=
--
prio_low
;
}
if
(
entry
->
rule
.
flags
&
AUDIT_FILTER_PREPEND
) {
list_add
(
&
entry
->
rule
.
list
,
&
audit_rules_list
[
entry
->
rule
.
listnr
]);
list_add_rcu
(
&
entry
->
list
,
list
);
entry
->
rule
.
flags
&= ~
AUDIT_FILTER_PREPEND
;
}
else
{
list_add_tail
(
&
entry
->
rule
.
list
,
&
audit_rules_list
[
entry
->
rule
.
listnr
]);
list_add_tail_rcu
(
&
entry
->
list
,
list
);
}
#ifdef
CONFIG_AUDITSYSCALL
if
(!
dont_count
)
audit_n_rules
++
;
if
(!
audit_match_signal
(
entry
))
audit_signals
++
;
#endif
mutex_unlock
(
&
audit_filter_mutex
);
return
0
;
error
:
if
(
watch
)
audit_put_watch
(
watch
);
/* tmp watch, matches initial get */
return
err
;
}
/* Remove an existing rule from filterlist. */
static
inline
int
audit_del_rule
(
struct
audit_entry
*
entry
)
{
struct
audit_entry
*
e
;
struct
audit_watch
*
watch
=
entry
->
rule
.
watch
;
struct
audit_tree
*
tree
=
entry
->
rule
.
tree
;
struct
list_head
*
list
;
int
ret
=
0
;
#ifdef
CONFIG_AUDITSYSCALL
int
dont_count
=
0
;
/* If either of these, don't count towards total */
if
(
entry
->
rule
.
listnr
==
AUDIT_FILTER_USER
||
entry
->
rule
.
listnr
==
AUDIT_FILTER_TYPE
)
dont_count
=
1
;
#endif
mutex_lock
(
&
audit_filter_mutex
);
e
=
audit_find_rule
(
entry
,
&
list
);
if
(!
e
) {
mutex_unlock
(
&
audit_filter_mutex
);
ret
=
-
ENOENT
;
goto
out
;
}
if
(
e
->
rule
.
watch
)
audit_remove_watch_rule
(
&
e
->
rule
);
if
(
e
->
rule
.
tree
)
audit_remove_tree_rule
(
&
e
->
rule
);
list_del_rcu
(
&
e
->
list
);
list_del
(
&
e
->
rule
.
list
);
call_rcu
(
&
e
->
rcu
,
audit_free_rule_rcu
);
#ifdef
CONFIG_AUDITSYSCALL
if
(!
dont_count
)
audit_n_rules
--
;
if
(!
audit_match_signal
(
entry
))
audit_signals
--
;
#endif
mutex_unlock
(
&
audit_filter_mutex
);
out
:
if
(
watch
)
audit_put_watch
(
watch
);
/* match initial get */
if
(
tree
)
audit_put_tree
(
tree
);
/* that's the temporary one */
return
ret
;
}
/* List rules using struct audit_rule. Exists for backward
* compatibility with userspace. */
static
void
audit_list
(
int
pid
,
int
seq
,
struct
sk_buff_head
*
q
)
{
struct
sk_buff
*
skb
;
struct
audit_krule
*
r
;
int
i
;
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