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AUDIT: Prevent duplicate syscall rules 

The following patch against audit.81 prevents duplicate syscall rules in
a given filter list by walking the list on each rule add.

I also removed the unused struct audit_entry in audit.c and made the
static inlines in auditsc.c consistent.

Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
This commit is contained in:
Amy Griffis 2005-08-17 16:05:35 +01:00 committed by David Woodhouse
parent c389649594
commit 3c789a1905
2 changed files with 56 additions and 44 deletions
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5
kernel/audit.c
View File

@ -142,11 +142,6 @@ static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
nlh->nlmsg_pid = pid;
}
struct audit_entry {
struct list_head list;
struct audit_rule rule;
};
static void audit_panic(const char *message)
{
switch (audit_failure)

95
kernel/auditsc.c
View File

@ -190,9 +190,36 @@ struct audit_entry {
extern int audit_pid;
/* 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 int audit_compare_rule(struct audit_rule *a, struct audit_rule *b)
static inline int audit_compare_rule(struct audit_rule *a, struct audit_rule *b)
{
int i;
@ -221,18 +248,37 @@ static int audit_compare_rule(struct audit_rule *a, struct audit_rule *b)
/* 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 void audit_add_rule(struct audit_entry *entry,
static inline int audit_add_rule(struct audit_rule *rule,
struct list_head *list)
{
struct audit_entry *entry;
/* 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;
}
}
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 void audit_free_rule(struct rcu_head *head)
static inline void audit_free_rule(struct rcu_head *head)
{
struct audit_entry *e = container_of(head, struct audit_entry, rcu);
kfree(e);
@ -258,32 +304,6 @@ static inline int audit_del_rule(struct audit_rule *rule,
return -ENOENT; /* No matching rule */
}
/* Copy rule from user-space to kernel-space. Called during
* AUDIT_ADD. */
static 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;
}
static int audit_list_rules(void *_dest)
{
int pid, seq;
@ -313,7 +333,6 @@ static int audit_list_rules(void *_dest)
int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
uid_t loginuid)
{
struct audit_entry *entry;
struct task_struct *tsk;
int *dest;
int err = 0;
@ -340,16 +359,14 @@ int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
}
break;
case AUDIT_ADD:
if (!(entry = kmalloc(sizeof(*entry), GFP_KERNEL)))
return -ENOMEM;
if (audit_copy_rule(&entry->rule, data)) {
kfree(entry);
listnr =((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND;
if (listnr >= AUDIT_NR_FILTERS)
return -EINVAL;
}
listnr = entry->rule.flags & ~AUDIT_FILTER_PREPEND;
audit_add_rule(entry, &audit_filter_list[listnr]);
audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
"auid=%u added an audit rule\n", loginuid);
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;