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authorAmy Griffis <amy.griffis@hp.com>2006-02-07 12:05:27 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2006-03-20 14:08:54 -0500
commit93315ed6dd12dacfc941f9eb8ca0293aadf99793 (patch)
tree4fc070c92a1de21d3befe4ce48c733c65d044bb3 /kernel/auditfilter.c
parentaf601e4623d0303bfafa54ec728b7ae8493a8e1b (diff)
[PATCH] audit string fields interface + consumer
Updated patch to dynamically allocate audit rule fields in kernel's internal representation. Added unlikely() calls for testing memory allocation result. Amy Griffis wrote: [Wed Jan 11 2006, 02:02:31PM EST] > Modify audit's kernel-userspace interface to allow the specification > of string fields in audit rules. > > Signed-off-by: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> (cherry picked from 5ffc4a863f92351b720fe3e9c5cd647accff9e03 commit)
Diffstat (limited to 'kernel/auditfilter.c')
-rw-r--r--kernel/auditfilter.c467
1 files changed, 357 insertions, 110 deletions
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index a3a32752f973..686d514a3518 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -40,52 +40,279 @@ struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
#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)
+static inline void audit_free_rule(struct audit_entry *e)
{
+ kfree(e->rule.fields);
+ kfree(e);
+}
+
+static inline void audit_free_rule_rcu(struct rcu_head *head)
+{
+ struct audit_entry *e = container_of(head, struct audit_entry, rcu);
+ audit_free_rule(e);
+}
+
+/* Unpack a filter field's string representation from user-space
+ * buffer. */
+static __attribute__((unused)) 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;
+}
+
+/* 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;
+ struct audit_field *fields;
+ int i, err;
+
+ err = -EINVAL;
+ listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
+ switch(listnr) {
+ default:
+ goto exit_err;
+ case AUDIT_FILTER_USER:
+ case AUDIT_FILTER_TYPE:
+#ifdef CONFIG_AUDITSYSCALL
+ case AUDIT_FILTER_ENTRY:
+ case AUDIT_FILTER_EXIT:
+ case AUDIT_FILTER_TASK:
+#endif
+ ;
+ }
+ if (rule->action != AUDIT_NEVER && rule->action != AUDIT_POSSIBLE &&
+ rule->action != AUDIT_ALWAYS)
+ goto exit_err;
+ if (rule->field_count > AUDIT_MAX_FIELDS)
+ goto exit_err;
+
+ err = -ENOMEM;
+ entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+ if (unlikely(!entry))
+ goto exit_err;
+ fields = kmalloc(sizeof(*fields) * rule->field_count, GFP_KERNEL);
+ if (unlikely(!fields)) {
+ kfree(entry);
+ goto exit_err;
+ }
+
+ memset(&entry->rule, 0, sizeof(struct audit_krule));
+ memset(fields, 0, sizeof(struct audit_field));
+
+ entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
+ entry->rule.listnr = listnr;
+ entry->rule.action = rule->action;
+ entry->rule.field_count = rule->field_count;
+ entry->rule.fields = fields;
+
+ for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
+ entry->rule.mask[i] = rule->mask[i];
+
+ return entry;
+
+exit_err:
+ return ERR_PTR(err);
+}
+
+/* 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;
- 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];
+ 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];
+
+ if (rule->fields[i] & AUDIT_UNUSED_BITS) {
+ err = -EINVAL;
+ goto exit_free;
+ }
+
+ f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
+ f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
+ f->val = rule->values[i];
+
+ entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;
+ if (f->op & AUDIT_NEGATE)
+ f->op |= AUDIT_NOT_EQUAL;
+ else if (!(f->op & AUDIT_OPERATORS))
+ f->op |= AUDIT_EQUAL;
+ f->op &= ~AUDIT_NEGATE;
}
- for (i = 0; i < AUDIT_BITMASK_SIZE; i++) d->mask[i] = s->mask[i];
- return 0;
+
+exit_nofree:
+ return entry;
+
+exit_free:
+ audit_free_rule(entry);
+ return ERR_PTR(err);
}
-/* 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)
+/* 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;
- if (a->flags != b->flags)
- return 1;
+ entry = audit_to_entry_common((struct audit_rule *)data);
+ if (IS_ERR(entry))
+ goto exit_nofree;
- if (a->action != b->action)
- return 1;
+ 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;
+ if (!(data->fieldflags[i] & AUDIT_OPERATORS) ||
+ data->fieldflags[i] & ~AUDIT_OPERATORS)
+ goto exit_free;
+
+ f->op = data->fieldflags[i] & AUDIT_OPERATORS;
+ f->type = data->fields[i];
+ switch(f->type) {
+ /* call type-specific conversion routines here */
+ default:
+ f->val = data->values[i];
+ }
+ }
+
+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, 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 = kmalloc(sizeof(*rule), GFP_KERNEL);
+ if (unlikely(!rule))
+ return ERR_PTR(-ENOMEM);
+ memset(rule, 0, sizeof(*rule));
+
+ 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] |= krule->fields[i].op;
+ }
+ }
+ for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
+
+ return rule;
+}
- if (a->field_count != b->field_count)
+/* 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 ERR_PTR(-ENOMEM);
+ 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] = f->op;
+ switch(f->type) {
+ /* call type-specific conversion routines here */
+ 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] != b->fields[i]
- || a->values[i] != b->values[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) {
+ /* call type-specific comparison routines here */
+ default:
+ if (a->fields[i].val != b->fields[i].val)
+ return 1;
+ }
}
for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
@@ -95,41 +322,21 @@ static int audit_compare_rule(struct audit_rule *a, struct audit_rule *b)
return 0;
}
-/* Note that audit_add_rule and audit_del_rule are called via
- * audit_receive() in audit.c, and are protected by
+/* Add rule to given filterlist if not a duplicate. Protected by
* audit_netlink_sem. */
-static inline int audit_add_rule(struct audit_rule *rule,
+static inline int audit_add_rule(struct audit_entry *entry,
struct list_head *list)
{
- struct audit_entry *entry;
- int i;
+ struct audit_entry *e;
/* 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))
+ list_for_each_entry(e, list, list) {
+ if (!audit_compare_rule(&entry->rule, &e->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);
@@ -138,16 +345,9 @@ static inline int audit_add_rule(struct audit_rule *rule,
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
+/* Remove an existing rule from filterlist. Protected by
* audit_netlink_sem. */
-static inline int audit_del_rule(struct audit_rule *rule,
+static inline int audit_del_rule(struct audit_entry *entry,
struct list_head *list)
{
struct audit_entry *e;
@@ -155,16 +355,18 @@ static inline int audit_del_rule(struct audit_rule *rule,
/* 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)) {
+ if (!audit_compare_rule(&entry->rule, &e->rule)) {
list_del_rcu(&e->list);
- call_rcu(&e->rcu, audit_free_rule);
+ call_rcu(&e->rcu, audit_free_rule_rcu);
return 0;
}
}
return -ENOENT; /* No matching rule */
}
-static int audit_list_rules(void *_dest)
+/* List rules using struct audit_rule. Exists for backward
+ * compatibility with userspace. */
+static int audit_list(void *_dest)
{
int pid, seq;
int *dest = _dest;
@@ -180,9 +382,16 @@ static int audit_list_rules(void *_dest)
/* 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)
+ list_for_each_entry(entry, &audit_filter_list[i], list) {
+ struct audit_rule *rule;
+
+ rule = audit_krule_to_rule(&entry->rule);
+ if (unlikely(!rule))
+ break;
audit_send_reply(pid, seq, AUDIT_LIST, 0, 1,
- &entry->rule, sizeof(entry->rule));
+ rule, sizeof(*rule));
+ kfree(rule);
+ }
}
audit_send_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
@@ -190,6 +399,40 @@ static int audit_list_rules(void *_dest)
return 0;
}
+/* List rules using struct audit_rule_data. */
+static int audit_list_rules(void *_dest)
+{
+ int pid, seq;
+ int *dest = _dest;
+ struct audit_entry *e;
+ 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(e, &audit_filter_list[i], list) {
+ struct audit_rule_data *data;
+
+ data = audit_krule_to_data(&e->rule);
+ if (unlikely(!data))
+ break;
+ audit_send_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
+ data, sizeof(*data));
+ kfree(data);
+ }
+ }
+ audit_send_reply(pid, seq, AUDIT_LIST_RULES, 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
@@ -197,18 +440,20 @@ static int audit_list_rules(void *_dest)
* @uid: target uid for netlink audit messages
* @seq: netlink audit message sequence (serial) number
* @data: payload data
+ * @datasz: size of payload data
* @loginuid: loginuid of sender
*/
int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
- uid_t loginuid)
+ size_t datasz, uid_t loginuid)
{
struct task_struct *tsk;
int *dest;
- int err = 0;
- unsigned listnr;
+ int err = 0;
+ struct audit_entry *entry;
switch (type) {
case AUDIT_LIST:
+ case AUDIT_LIST_RULES:
/* 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
@@ -221,41 +466,48 @@ int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
dest[0] = pid;
dest[1] = seq;
- tsk = kthread_run(audit_list_rules, dest, "audit_list_rules");
+ if (type == AUDIT_LIST)
+ tsk = kthread_run(audit_list, dest, "audit_list");
+ else
+ 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]);
+ case AUDIT_ADD_RULE:
+ if (type == AUDIT_ADD)
+ entry = audit_rule_to_entry(data);
+ else
+ entry = audit_data_to_entry(data, datasz);
+ if (IS_ERR(entry))
+ return PTR_ERR(entry);
+
+ err = audit_add_rule(entry,
+ &audit_filter_list[entry->rule.listnr]);
if (!err)
audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
"auid=%u added an audit rule\n", loginuid);
+ else
+ audit_free_rule(entry);
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]);
+ case AUDIT_DEL_RULE:
+ if (type == AUDIT_DEL)
+ entry = audit_rule_to_entry(data);
+ else
+ entry = audit_data_to_entry(data, datasz);
+ if (IS_ERR(entry))
+ return PTR_ERR(entry);
+
+ err = audit_del_rule(entry,
+ &audit_filter_list[entry->rule.listnr]);
if (!err)
audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
"auid=%u removed an audit rule\n", loginuid);
+ audit_free_rule(entry);
break;
default:
return -EINVAL;
@@ -287,29 +539,27 @@ int audit_comparator(const u32 left, const u32 op, const u32 right)
static int audit_filter_user_rules(struct netlink_skb_parms *cb,
- struct audit_rule *rule,
+ struct audit_krule *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];
+ struct audit_field *f = &rule->fields[i];
int result = 0;
- switch (field) {
+ switch (f->type) {
case AUDIT_PID:
- result = audit_comparator(cb->creds.pid, op, value);
+ result = audit_comparator(cb->creds.pid, f->op, f->val);
break;
case AUDIT_UID:
- result = audit_comparator(cb->creds.uid, op, value);
+ result = audit_comparator(cb->creds.uid, f->op, f->val);
break;
case AUDIT_GID:
- result = audit_comparator(cb->creds.gid, op, value);
+ result = audit_comparator(cb->creds.gid, f->op, f->val);
break;
case AUDIT_LOGINUID:
- result = audit_comparator(cb->loginuid, op, value);
+ result = audit_comparator(cb->loginuid, f->op, f->val);
break;
}
@@ -354,14 +604,11 @@ int audit_filter_type(int type)
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);
+ for (i = 0; i < e->rule.field_count; i++) {
+ struct audit_field *f = &e->rule.fields[i];
+ if (f->type == AUDIT_MSGTYPE) {
+ result = audit_comparator(type, f->op, f->val);
if (!result)
break;
}

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