original development tree for Linux kernel GTP module; now long in mainline.
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
linux-gtp/kernel/auditfilter.c

1390 lines
33 KiB

/* 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 cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
13 years ago
#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;
#ifdef CONFIG_AUDITSYSCALL
case AUDIT_FILTER_ENTRY:
if (rule->action == AUDIT_ALWAYS)
goto exit_err;
case AUDIT_FILTER_EXIT:
case AUDIT_FILTER_TASK:
#endif
case AUDIT_FILTER_USER:
case AUDIT_FILTER_TYPE:
;
}
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)
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:
case AUDIT_OBJ_UID:
case AUDIT_OBJ_GID:
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:
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)
goto exit_free;
break;
case AUDIT_FIELD_COMPARE:
if (f->val > AUDIT_MAX_FIELD_COMPARE)
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++) {