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>
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@ -142,11 +142,6 @@ static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
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nlh->nlmsg_pid = pid;
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nlh->nlmsg_pid = pid;
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}
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}
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struct audit_entry {
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struct list_head list;
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struct audit_rule rule;
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};
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static void audit_panic(const char *message)
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static void audit_panic(const char *message)
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{
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{
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switch (audit_failure)
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switch (audit_failure)
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@ -190,9 +190,36 @@ struct audit_entry {
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extern int audit_pid;
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extern int audit_pid;
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/* Copy rule from user-space to kernel-space. Called from
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* audit_add_rule during AUDIT_ADD. */
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static inline int audit_copy_rule(struct audit_rule *d, struct audit_rule *s)
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{
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int i;
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if (s->action != AUDIT_NEVER
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&& s->action != AUDIT_POSSIBLE
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&& s->action != AUDIT_ALWAYS)
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return -1;
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if (s->field_count < 0 || s->field_count > AUDIT_MAX_FIELDS)
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return -1;
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if ((s->flags & ~AUDIT_FILTER_PREPEND) >= AUDIT_NR_FILTERS)
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return -1;
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d->flags = s->flags;
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d->action = s->action;
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d->field_count = s->field_count;
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for (i = 0; i < d->field_count; i++) {
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d->fields[i] = s->fields[i];
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d->values[i] = s->values[i];
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}
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for (i = 0; i < AUDIT_BITMASK_SIZE; i++) d->mask[i] = s->mask[i];
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return 0;
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}
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/* Check to see if two rules are identical. It is called from
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/* Check to see if two rules are identical. It is called from
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* audit_add_rule during AUDIT_ADD and
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* audit_del_rule during AUDIT_DEL. */
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* audit_del_rule during AUDIT_DEL. */
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static int audit_compare_rule(struct audit_rule *a, struct audit_rule *b)
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static inline int audit_compare_rule(struct audit_rule *a, struct audit_rule *b)
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{
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{
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int i;
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int i;
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@ -221,18 +248,37 @@ static int audit_compare_rule(struct audit_rule *a, struct audit_rule *b)
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/* Note that audit_add_rule and audit_del_rule are called via
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/* Note that audit_add_rule and audit_del_rule are called via
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* audit_receive() in audit.c, and are protected by
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* audit_receive() in audit.c, and are protected by
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* audit_netlink_sem. */
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* audit_netlink_sem. */
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static inline void audit_add_rule(struct audit_entry *entry,
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static inline int audit_add_rule(struct audit_rule *rule,
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struct list_head *list)
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struct list_head *list)
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{
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{
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struct audit_entry *entry;
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/* Do not use the _rcu iterator here, since this is the only
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* addition routine. */
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list_for_each_entry(entry, list, list) {
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if (!audit_compare_rule(rule, &entry->rule)) {
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return -EEXIST;
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}
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}
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if (!(entry = kmalloc(sizeof(*entry), GFP_KERNEL)))
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return -ENOMEM;
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if (audit_copy_rule(&entry->rule, rule)) {
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kfree(entry);
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return -EINVAL;
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}
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if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
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if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
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entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
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entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
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list_add_rcu(&entry->list, list);
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list_add_rcu(&entry->list, list);
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} else {
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} else {
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list_add_tail_rcu(&entry->list, list);
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list_add_tail_rcu(&entry->list, list);
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}
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}
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return 0;
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}
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}
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static void audit_free_rule(struct rcu_head *head)
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static inline void audit_free_rule(struct rcu_head *head)
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{
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{
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struct audit_entry *e = container_of(head, struct audit_entry, rcu);
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struct audit_entry *e = container_of(head, struct audit_entry, rcu);
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kfree(e);
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kfree(e);
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@ -258,32 +304,6 @@ static inline int audit_del_rule(struct audit_rule *rule,
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return -ENOENT; /* No matching rule */
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return -ENOENT; /* No matching rule */
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}
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}
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/* Copy rule from user-space to kernel-space. Called during
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* AUDIT_ADD. */
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static int audit_copy_rule(struct audit_rule *d, struct audit_rule *s)
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{
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int i;
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if (s->action != AUDIT_NEVER
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&& s->action != AUDIT_POSSIBLE
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&& s->action != AUDIT_ALWAYS)
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return -1;
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if (s->field_count < 0 || s->field_count > AUDIT_MAX_FIELDS)
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return -1;
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if ((s->flags & ~AUDIT_FILTER_PREPEND) >= AUDIT_NR_FILTERS)
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return -1;
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d->flags = s->flags;
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d->action = s->action;
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d->field_count = s->field_count;
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for (i = 0; i < d->field_count; i++) {
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d->fields[i] = s->fields[i];
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d->values[i] = s->values[i];
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}
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for (i = 0; i < AUDIT_BITMASK_SIZE; i++) d->mask[i] = s->mask[i];
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return 0;
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}
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static int audit_list_rules(void *_dest)
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static int audit_list_rules(void *_dest)
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{
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{
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int pid, seq;
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int pid, seq;
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@ -313,7 +333,6 @@ static int audit_list_rules(void *_dest)
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int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
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int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
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uid_t loginuid)
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uid_t loginuid)
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{
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{
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struct audit_entry *entry;
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struct task_struct *tsk;
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struct task_struct *tsk;
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int *dest;
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int *dest;
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int err = 0;
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int err = 0;
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@ -340,14 +359,12 @@ int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
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}
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}
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break;
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break;
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case AUDIT_ADD:
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case AUDIT_ADD:
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if (!(entry = kmalloc(sizeof(*entry), GFP_KERNEL)))
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listnr =((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND;
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return -ENOMEM;
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if (listnr >= AUDIT_NR_FILTERS)
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if (audit_copy_rule(&entry->rule, data)) {
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kfree(entry);
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return -EINVAL;
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return -EINVAL;
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}
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listnr = entry->rule.flags & ~AUDIT_FILTER_PREPEND;
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err = audit_add_rule(data, &audit_filter_list[listnr]);
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audit_add_rule(entry, &audit_filter_list[listnr]);
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if (!err)
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audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
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audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
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"auid=%u added an audit rule\n", loginuid);
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"auid=%u added an audit rule\n", loginuid);
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break;
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break;
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