Commit fe7752ba authored by David Woodhouse's avatar David Woodhouse Committed by Al Viro

[PATCH] Fix audit record filtering with !CONFIG_AUDITSYSCALL

This fixes the per-user and per-message-type filtering when syscall
auditing isn't enabled.

[AV: folded followup fix from the same author]
Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ee436dc4
......@@ -278,8 +278,6 @@ static inline void audit_inode_child(const char *dname,
}
/* Private API (for audit.c only) */
extern int audit_receive_filter(int type, int pid, int uid, int seq,
void *data, uid_t loginuid);
extern unsigned int audit_serial(void);
extern void auditsc_get_stamp(struct audit_context *ctx,
struct timespec *t, unsigned int *serial);
......@@ -290,8 +288,6 @@ extern int audit_socketcall(int nargs, unsigned long *args);
extern int audit_sockaddr(int len, void *addr);
extern int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt);
extern void audit_signal_info(int sig, struct task_struct *t);
extern int audit_filter_user(struct netlink_skb_parms *cb, int type);
extern int audit_filter_type(int type);
extern int audit_set_macxattr(const char *name);
#else
#define audit_alloc(t) ({ 0; })
......@@ -304,7 +300,6 @@ extern int audit_set_macxattr(const char *name);
#define __audit_inode_child(d,i,p) do { ; } while (0)
#define audit_inode(n,i,f) do { ; } while (0)
#define audit_inode_child(d,i,p) do { ; } while (0)
#define audit_receive_filter(t,p,u,s,d,l) ({ -EOPNOTSUPP; })
#define auditsc_get_stamp(c,t,s) do { BUG(); } while (0)
#define audit_get_loginuid(c) ({ -1; })
#define audit_ipc_perms(q,u,g,m,i) ({ 0; })
......@@ -312,7 +307,6 @@ extern int audit_set_macxattr(const char *name);
#define audit_sockaddr(len, addr) ({ 0; })
#define audit_avc_path(dentry, mnt) ({ 0; })
#define audit_signal_info(s,t) do { ; } while (0)
#define audit_filter_user(cb,t) ({ 1; })
#define audit_set_macxattr(n) do { ; } while (0)
#endif
......@@ -337,13 +331,11 @@ extern void audit_log_d_path(struct audit_buffer *ab,
const char *prefix,
struct dentry *dentry,
struct vfsmount *vfsmnt);
/* Private API (for auditsc.c only) */
extern void audit_send_reply(int pid, int seq, int type,
int done, int multi,
void *payload, int size);
extern void audit_log_lost(const char *message);
extern void audit_panic(const char *message);
extern struct semaphore audit_netlink_sem;
/* Private API (for audit.c only) */
extern int audit_filter_user(struct netlink_skb_parms *cb, int type);
extern int audit_filter_type(int type);
extern int audit_receive_filter(int type, int pid, int uid, int seq,
void *data, uid_t loginuid);
#else
#define audit_log(c,g,t,f,...) do { ; } while (0)
#define audit_log_start(c,g,t) ({ NULL; })
......
......@@ -26,7 +26,7 @@ obj-$(CONFIG_COMPAT) += compat.o
obj-$(CONFIG_CPUSETS) += cpuset.o
obj-$(CONFIG_IKCONFIG) += configs.o
obj-$(CONFIG_STOP_MACHINE) += stop_machine.o
obj-$(CONFIG_AUDIT) += audit.o
obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_SYSFS) += ksysfs.o
......
......@@ -305,6 +305,7 @@ static int kauditd_thread(void *dummy)
remove_wait_queue(&kauditd_wait, &wait);
}
}
return 0;
}
/**
......
/* audit -- definition of audit_context structure and supporting types
*
* 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/fs.h>
#include <linux/audit.h>
/* 0 = no checking
1 = put_count checking
2 = verbose put_count checking
*/
#define AUDIT_DEBUG 0
/* At task start time, the audit_state is set in the audit_context using
a per-task filter. At syscall entry, the audit_state is augmented by
the syscall filter. */
enum audit_state {
AUDIT_DISABLED, /* Do not create per-task audit_context.
* No syscall-specific audit records can
* be generated. */
AUDIT_SETUP_CONTEXT, /* Create the per-task audit_context,
* but don't necessarily fill it in at
* syscall entry time (i.e., filter
* instead). */
AUDIT_BUILD_CONTEXT, /* Create the per-task audit_context,
* and always fill it in at syscall
* entry time. This makes a full
* syscall record available if some
* other part of the kernel decides it
* should be recorded. */
AUDIT_RECORD_CONTEXT /* Create the per-task audit_context,
* always fill it in at syscall entry
* time, and always write out the audit
* record at syscall exit time. */
};
/* Rule lists */
struct audit_entry {
struct list_head list;
struct rcu_head rcu;
struct audit_rule rule;
};
extern int audit_pid;
extern int audit_comparator(const u32 left, const u32 op, const u32 right);
extern void audit_send_reply(int pid, int seq, int type,
int done, int multi,
void *payload, int size);
extern void audit_log_lost(const char *message);
extern void audit_panic(const char *message);
extern struct semaphore audit_netlink_sem;
/* 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/netlink.h>
#include "audit.h"
/* There are three lists of rules -- one to search at task creation
* time, one to search at syscall entry time, and another to search at
* syscall exit time. */
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
};
/* Copy rule from user-space to kernel-space. Called from
* audit_add_rule during AUDIT_ADD. */
static inline int audit_copy_rule(struct audit_rule *d, struct audit_rule *s)
{
int i;
if (s->action != AUDIT_NEVER
&& s->action != AUDIT_POSSIBLE
&& s->action != AUDIT_ALWAYS)
return -1;
if (s->field_count < 0 || s->field_count > AUDIT_MAX_FIELDS)
return -1;
if ((s->flags & ~AUDIT_FILTER_PREPEND) >= AUDIT_NR_FILTERS)
return -1;
d->flags = s->flags;
d->action = s->action;
d->field_count = s->field_count;
for (i = 0; i < d->field_count; i++) {
d->fields[i] = s->fields[i];
d->values[i] = s->values[i];
}
for (i = 0; i < AUDIT_BITMASK_SIZE; i++) d->mask[i] = s->mask[i];
return 0;
}
/* Check to see if two rules are identical. It is called from
* audit_add_rule during AUDIT_ADD and
* audit_del_rule during AUDIT_DEL. */
static inline int audit_compare_rule(struct audit_rule *a, struct audit_rule *b)
{
int i;
if (a->flags != b->flags)
return 1;
if (a->action != b->action)
return 1;
if (a->field_count != b->field_count)
return 1;
for (i = 0; i < a->field_count; i++) {
if (a->fields[i] != b->fields[i]
|| a->values[i] != b->values[i])
return 1;
}
for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
if (a->mask[i] != b->mask[i])
return 1;
return 0;
}
/* Note that audit_add_rule and audit_del_rule are called via
* audit_receive() in audit.c, and are protected by
* audit_netlink_sem. */
static inline int audit_add_rule(struct audit_rule *rule,
struct list_head *list)
{
struct audit_entry *entry;
int i;
/* Do not use the _rcu iterator here, since this is the only
* addition routine. */
list_for_each_entry(entry, list, list) {
if (!audit_compare_rule(rule, &entry->rule)) {
return -EEXIST;
}
}
for (i = 0; i < rule->field_count; i++) {
if (rule->fields[i] & AUDIT_UNUSED_BITS)
return -EINVAL;
if ( rule->fields[i] & AUDIT_NEGATE )
rule->fields[i] |= AUDIT_NOT_EQUAL;
else if ( (rule->fields[i] & AUDIT_OPERATORS) == 0 )
rule->fields[i] |= AUDIT_EQUAL;
rule->fields[i] &= (~AUDIT_NEGATE);
}
if (!(entry = kmalloc(sizeof(*entry), GFP_KERNEL)))
return -ENOMEM;
if (audit_copy_rule(&entry->rule, rule)) {
kfree(entry);
return -EINVAL;
}
if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
list_add_rcu(&entry->list, list);
} else {
list_add_tail_rcu(&entry->list, list);
}
return 0;
}
static inline void audit_free_rule(struct rcu_head *head)
{
struct audit_entry *e = container_of(head, struct audit_entry, rcu);
kfree(e);
}
/* Note that audit_add_rule and audit_del_rule are called via
* audit_receive() in audit.c, and are protected by
* audit_netlink_sem. */
static inline int audit_del_rule(struct audit_rule *rule,
struct list_head *list)
{
struct audit_entry *e;
/* Do not use the _rcu iterator here, since this is the only
* deletion routine. */
list_for_each_entry(e, list, list) {
if (!audit_compare_rule(rule, &e->rule)) {
list_del_rcu(&e->list);
call_rcu(&e->rcu, audit_free_rule);
return 0;
}
}
return -ENOENT; /* No matching rule */
}
static int audit_list_rules(void *_dest)
{
int pid, seq;
int *dest = _dest;
struct audit_entry *entry;
int i;
pid = dest[0];
seq = dest[1];
kfree(dest);
down(&audit_netlink_sem);
/* The *_rcu iterators not needed here because we are
always called with audit_netlink_sem held. */
for (i=0; i<AUDIT_NR_FILTERS; i++) {
list_for_each_entry(entry, &audit_filter_list[i], list)
audit_send_reply(pid, seq, AUDIT_LIST, 0, 1,
&entry->rule, sizeof(entry->rule));
}
audit_send_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
up(&audit_netlink_sem);
return 0;
}
/**
* audit_receive_filter - apply all rules to the specified message type
* @type: audit message type
* @pid: target pid for netlink audit messages
* @uid: target uid for netlink audit messages
* @seq: netlink audit message sequence (serial) number
* @data: payload data
* @loginuid: loginuid of sender
*/
int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
uid_t loginuid)
{
struct task_struct *tsk;
int *dest;
int err = 0;
unsigned listnr;
switch (type) {
case AUDIT_LIST:
/* We can't just spew out the rules here because we might fill
* the available socket buffer space and deadlock waiting for
* auditctl to read from it... which isn't ever going to
* happen if we're actually running in the context of auditctl
* trying to _send_ the stuff */
dest = kmalloc(2 * sizeof(int), GFP_KERNEL);
if (!dest)
return -ENOMEM;
dest[0] = pid;
dest[1] = seq;
tsk = kthread_run(audit_list_rules, dest, "audit_list_rules");
if (IS_ERR(tsk)) {
kfree(dest);
err = PTR_ERR(tsk);
}
break;
case AUDIT_ADD:
listnr = ((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND;
switch(listnr) {
default:
return -EINVAL;
case AUDIT_FILTER_USER:
case AUDIT_FILTER_TYPE:
#ifdef CONFIG_AUDITSYSCALL
case AUDIT_FILTER_ENTRY:
case AUDIT_FILTER_EXIT:
case AUDIT_FILTER_TASK:
#endif
;
}
err = audit_add_rule(data, &audit_filter_list[listnr]);
if (!err)
audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
"auid=%u added an audit rule\n", loginuid);
break;
case AUDIT_DEL:
listnr =((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND;
if (listnr >= AUDIT_NR_FILTERS)
return -EINVAL;
err = audit_del_rule(data, &audit_filter_list[listnr]);
if (!err)
audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
"auid=%u removed an audit rule\n", loginuid);
break;
default:
return -EINVAL;
}
return err;
}
int audit_comparator(const u32 left, const u32 op, const u32 right)
{
switch (op) {
case AUDIT_EQUAL:
return (left == right);
case AUDIT_NOT_EQUAL:
return (left != right);
case AUDIT_LESS_THAN:
return (left < right);
case AUDIT_LESS_THAN_OR_EQUAL:
return (left <= right);
case AUDIT_GREATER_THAN:
return (left > right);
case AUDIT_GREATER_THAN_OR_EQUAL:
return (left >= right);
default:
return -EINVAL;
}
}
static int audit_filter_user_rules(struct netlink_skb_parms *cb,
struct audit_rule *rule,
enum audit_state *state)
{
int i;
for (i = 0; i < rule->field_count; i++) {
u32 field = rule->fields[i] & ~AUDIT_OPERATORS;
u32 op = rule->fields[i] & AUDIT_OPERATORS;
u32 value = rule->values[i];
int result = 0;
switch (field) {
case AUDIT_PID:
result = audit_comparator(cb->creds.pid, op, value);
break;
case AUDIT_UID:
result = audit_comparator(cb->creds.uid, op, value);
break;
case AUDIT_GID:
result = audit_comparator(cb->creds.gid, op, value);
break;
case AUDIT_LOGINUID:
result = audit_comparator(cb->loginuid, op, value);
break;
}
if (!result)
return 0;
}
switch (rule->action) {
case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
case AUDIT_POSSIBLE: *state = AUDIT_BUILD_CONTEXT; break;
case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
}
return 1;
}
int audit_filter_user(struct netlink_skb_parms *cb, int type)
{
struct audit_entry *e;
enum audit_state state;
int ret = 1;
rcu_read_lock();
list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
if (audit_filter_user_rules(cb, &e->rule, &state)) {
if (state == AUDIT_DISABLED)
ret = 0;
break;
}
}
rcu_read_unlock();
return ret; /* Audit by default */
}
int audit_filter_type(int type)
{
struct audit_entry *e;
int result = 0;
rcu_read_lock();
if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
goto unlock_and_return;
list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
list) {
struct audit_rule *rule = &e->rule;
int i;
for (i = 0; i < rule->field_count; i++) {
u32 field = rule->fields[i] & ~AUDIT_OPERATORS;
u32 op = rule->fields[i] & AUDIT_OPERATORS;
u32 value = rule->values[i];
if ( field == AUDIT_MSGTYPE ) {
result = audit_comparator(type, op, value);
if (!result)
break;
}
}
if (result)
goto unlock_and_return;
}
unlock_and_return:
rcu_read_unlock();
return result;
}
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