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authorLinus Torvalds <torvalds@g5.osdl.org>2006-03-25 09:24:53 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-25 09:24:53 -0800
commit1b9a3917366028cc451a98dd22e3bcd537d4e5c1 (patch)
treed911058720e0a9aeeaf9f407ccdc6fbf4047f47d /kernel/auditfilter.c
parentMerge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/aoe-2.6 (diff)
parent[PATCH] fix audit_init failure path (diff)
downloadlinux-dev-1b9a3917366028cc451a98dd22e3bcd537d4e5c1.tar.xz
linux-dev-1b9a3917366028cc451a98dd22e3bcd537d4e5c1.zip
Merge branch 'audit.b3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current
* 'audit.b3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current: (22 commits) [PATCH] fix audit_init failure path [PATCH] EXPORT_SYMBOL patch for audit_log, audit_log_start, audit_log_end and audit_format [PATCH] sem2mutex: audit_netlink_sem [PATCH] simplify audit_free() locking [PATCH] Fix audit operators [PATCH] promiscuous mode [PATCH] Add tty to syscall audit records [PATCH] add/remove rule update [PATCH] audit string fields interface + consumer [PATCH] SE Linux audit events [PATCH] Minor cosmetic cleanups to the code moved into auditfilter.c [PATCH] Fix audit record filtering with !CONFIG_AUDITSYSCALL [PATCH] Fix IA64 success/failure indication in syscall auditing. [PATCH] Miscellaneous bug and warning fixes [PATCH] Capture selinux subject/object context information. [PATCH] Exclude messages by message type [PATCH] Collect more inode information during syscall processing. [PATCH] Pass dentry, not just name, in fsnotify creation hooks. [PATCH] Define new range of userspace messages. [PATCH] Filter rule comparators ... Fixed trivial conflict in security/selinux/hooks.c
Diffstat (limited to 'kernel/auditfilter.c')
-rw-r--r--kernel/auditfilter.c630
1 files changed, 630 insertions, 0 deletions
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
new file mode 100644
index 000000000000..d3a8539f3a83
--- /dev/null
+++ b/kernel/auditfilter.c
@@ -0,0 +1,630 @@
+/* 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
+};
+
+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;
+
+ 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;
+
+ /* Support for legacy operators where
+ * AUDIT_NEGATE bit signifies != and otherwise assumes == */
+ if (f->op & AUDIT_NEGATE)
+ f->op = AUDIT_NOT_EQUAL;
+ else if (!f->op)
+ f->op = AUDIT_EQUAL;
+ else if (f->op == AUDIT_OPERATORS) {
+ err = -EINVAL;
+ goto exit_free;
+ }
+ }
+
+exit_nofree:
+ return entry;
+
+exit_free:
+ audit_free_rule(entry);
+ return ERR_PTR(err);
+}
+
+/* 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;
+
+ 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;
+ 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;
+}
+
+/* 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].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++)
+ if (a->mask[i] != b->mask[i])
+ return 1;
+
+ return 0;
+}
+
+/* Add rule to given filterlist if not a duplicate. Protected by
+ * audit_netlink_mutex. */
+static inline int audit_add_rule(struct audit_entry *entry,
+ struct list_head *list)
+{
+ struct audit_entry *e;
+
+ /* Do not use the _rcu iterator here, since this is the only
+ * addition routine. */
+ list_for_each_entry(e, list, list) {
+ if (!audit_compare_rule(&entry->rule, &e->rule))
+ return -EEXIST;
+ }
+
+ if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
+ list_add_rcu(&entry->list, list);
+ } else {
+ list_add_tail_rcu(&entry->list, list);
+ }
+
+ return 0;
+}
+
+/* Remove an existing rule from filterlist. Protected by
+ * audit_netlink_mutex. */
+static inline int audit_del_rule(struct audit_entry *entry,
+ 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(&entry->rule, &e->rule)) {
+ list_del_rcu(&e->list);
+ call_rcu(&e->rcu, audit_free_rule_rcu);
+ return 0;
+ }
+ }
+ return -ENOENT; /* No matching rule */
+}
+
+/* List rules using struct audit_rule. Exists for backward
+ * compatibility with userspace. */
+static int audit_list(void *_dest)
+{
+ int pid, seq;
+ int *dest = _dest;
+ struct audit_entry *entry;
+ int i;
+
+ pid = dest[0];
+ seq = dest[1];
+ kfree(dest);
+
+ mutex_lock(&audit_netlink_mutex);
+
+ /* The *_rcu iterators not needed here because we are
+ always called with audit_netlink_mutex held. */
+ for (i=0; i<AUDIT_NR_FILTERS; i++) {
+ 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,
+ rule, sizeof(*rule));
+ kfree(rule);
+ }
+ }
+ audit_send_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
+
+ mutex_unlock(&audit_netlink_mutex);
+ 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);
+
+ mutex_lock(&audit_netlink_mutex);
+
+ /* The *_rcu iterators not needed here because we are
+ always called with audit_netlink_mutex 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);
+
+ mutex_unlock(&audit_netlink_mutex);
+ 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
+ * @datasz: size of payload data
+ * @loginuid: loginuid of sender
+ */
+int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
+ size_t datasz, uid_t loginuid)
+{
+ struct task_struct *tsk;
+ int *dest;
+ 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
+ * 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;
+
+ 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:
+ 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]);
+ audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
+ "auid=%u add rule to list=%d res=%d\n",
+ loginuid, entry->rule.listnr, !err);
+
+ if (err)
+ audit_free_rule(entry);
+ break;
+ case AUDIT_DEL:
+ 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]);
+ audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
+ "auid=%u remove rule from list=%d res=%d\n",
+ loginuid, entry->rule.listnr, !err);
+
+ audit_free_rule(entry);
+ 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);
+ }
+ BUG();
+ return 0;
+}
+
+
+
+static int audit_filter_user_rules(struct netlink_skb_parms *cb,
+ struct audit_krule *rule,
+ enum audit_state *state)
+{
+ int i;
+
+ for (i = 0; i < rule->field_count; i++) {
+ struct audit_field *f = &rule->fields[i];
+ int result = 0;
+
+ switch (f->type) {
+ case AUDIT_PID:
+ result = audit_comparator(cb->creds.pid, f->op, f->val);
+ break;
+ case AUDIT_UID:
+ result = audit_comparator(cb->creds.uid, f->op, f->val);
+ break;
+ case AUDIT_GID:
+ result = audit_comparator(cb->creds.gid, f->op, f->val);
+ break;
+ case AUDIT_LOGINUID:
+ result = audit_comparator(cb->loginuid, f->op, f->val);
+ 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) {
+ int i;
+ 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;
+ }
+ }
+ if (result)
+ goto unlock_and_return;
+ }
+unlock_and_return:
+ rcu_read_unlock();
+ return result;
+}