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/* auditfilter.c -- filtering of audit events

* 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;

#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;

}

/* check if an audit field is valid */

static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)

{

switch(f->type) {

case AUDIT_MSGTYPE:

if (entry->rule.listnr != AUDIT_FILTER_TYPE &&

entry->rule.listnr != AUDIT_FILTER_USER)

return -EINVAL;

break;

};

switch(f->type) {

default:

return -EINVAL;

case AUDIT_UID:

case AUDIT_EUID:

case AUDIT_SUID:

case AUDIT_FSUID:

case AUDIT_LOGINUID:

case AUDIT_OBJ_UID:

case AUDIT_GID:

case AUDIT_EGID:

case AUDIT_SGID:

case AUDIT_FSGID:

case AUDIT_OBJ_GID:

case AUDIT_PID:

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)

return -EINVAL;

break;

case AUDIT_ARG0:

case AUDIT_ARG1:

case AUDIT_ARG2:

case AUDIT_ARG3:

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:

case AUDIT_WATCH:

case AUDIT_DIR:

case AUDIT_FILTERKEY:

break;

case AUDIT_LOGINUID_SET:

if ((f->val != 0) && (f->val != 1))

return -EINVAL;

/* FALL THROUGH */

case AUDIT_ARCH:

if (f->op != Audit_not_equal && f->op != Audit_equal)

return -EINVAL;

break;

case AUDIT_PERM:

if (f->val & ~15)

return -EINVAL;

break;

case AUDIT_FILETYPE:

if (f->val & ~S_IFMT)

return -EINVAL;

break;

case AUDIT_FIELD_COMPARE:

if (f->val > AUDIT_MAX_FIELD_COMPARE)

return -EINVAL;

break;

};

return 0;

}

/* 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->uid = INVALID_UID;

f->gid = INVALID_GID;

f->lsm_str = NULL;

f->lsm_rule = NULL;

/* Support legacy tests for a valid loginuid */

if ((f->type == AUDIT_LOGINUID) && (f->val == ~0U)) {

f->type = AUDIT_LOGINUID_SET;

f->val = 0;

}

err = audit_field_valid(entry, f);

if (err)

goto exit_free;

err = -EINVAL;

switch (f->type) {

case AUDIT_LOGINUID:

case AUDIT_UID:

case AUDIT_EUID:

case AUDIT_SUID:

case AUDIT_FSUID:

case AUDIT_OBJ_UID:

f->uid = make_kuid(current_user_ns(), f->val);

if (!uid_valid(f->uid))

goto exit_free;

break;

case AUDIT_GID:

case AUDIT_EGID:

case AUDIT_SGID:

case AUDIT_FSGID:

case AUDIT_OBJ_GID:

f->gid = make_kgid(current_user_ns(), f->val);

if (!gid_valid(f->gid))

goto exit_free;

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;

}

if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)

entry->rule.inode_f = NULL;

exit_nofree:

return entry;

exit_free:

if (entry->rule.watch)

audit_put_watch(entry->rule.watch); /* matches initial get */

if (entry->rule.tree)

audit_put_tree(entry->rule.tree); /* that's the temporary one */

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_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;

case AUDIT_UID:

case AUDIT_EUID:

case AUDIT_SUID:

case AUDIT_FSUID:

case AUDIT_LOGINUID:

case AUDIT_OBJ_UID:

if (!uid_eq(a->fields[i].uid, b->fields[i].uid))

return 1;

break;

case AUDIT_GID:

case AUDIT_EGID:

case AUDIT_SGID:

case AUDIT_FSGID:

case AUDIT_OBJ_GID:

if (!gid_eq(a->fields[i].gid, b->fields[i].gid))

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);

* normally audit_add_tree_rule() will free it

* on failure

if (tree)

audit_put_tree(tree);

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_data. */

static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)

{

struct sk_buff *skb;

struct audit_krule *r;

int i;

/* This is a blocking read, so use audit_filter_mutex instead of rcu

* iterator to sync with list writers. */

for (i=0; i<AUDIT_NR_FILTERS; i++) {

list_for_each_entry(r, &audit_rules_list[i], list) {

struct audit_rule_data *data;

data = audit_krule_to_data(r);

if (unlikely(!data))

break;

skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,

data, sizeof(*data) + data->buflen);

if (skb)

skb_queue_tail(q, skb);

kfree(data);

}

skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);

if (skb)

skb_queue_tail(q, skb);

}

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linux/kernel/auditfilter.c at master · fabgithub/linux · GitHub

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