--- /dev/null
+/* 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
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/audit.h>
+#include <linux/kthread.h>
+#include <linux/mutex.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/netlink.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
+#include "audit.h"
+
+/*
+ * Locking model:
+ *
+ * audit_filter_mutex:
+ * Synchronizes writes and blocking reads of audit's filterlist
+ * data. Rcu is used to traverse the filterlist and access
+ * contents of structs audit_entry, audit_watch and opaque
+ * LSM rules during filtering. If modified, these structures
+ * must be copied and replace their counterparts in the filterlist.
+ * An audit_parent struct is not accessed during filtering, so may
+ * be written directly provided audit_filter_mutex is held.
+ */
+
+/* Audit filter lists, defined in <linux/audit.h> */
+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 struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
+ LIST_HEAD_INIT(audit_rules_list[0]),
+ LIST_HEAD_INIT(audit_rules_list[1]),
+ LIST_HEAD_INIT(audit_rules_list[2]),
+ LIST_HEAD_INIT(audit_rules_list[3]),
+ LIST_HEAD_INIT(audit_rules_list[4]),
+ LIST_HEAD_INIT(audit_rules_list[5]),
+};
+
+DEFINE_MUTEX(audit_filter_mutex);
+
+static void audit_free_lsm_field(struct audit_field *f)
+{
+ switch (f->type) {
+ case AUDIT_SUBJ_USER:
+ case AUDIT_SUBJ_ROLE:
+ case AUDIT_SUBJ_TYPE:
+ case AUDIT_SUBJ_SEN:
+ case AUDIT_SUBJ_CLR:
+ case AUDIT_OBJ_USER:
+ case AUDIT_OBJ_ROLE:
+ case AUDIT_OBJ_TYPE:
+ case AUDIT_OBJ_LEV_LOW:
+ case AUDIT_OBJ_LEV_HIGH:
+ kfree(f->lsm_str);
+ security_audit_rule_free(f->lsm_rule);
+ }
+}
+
+static inline void audit_free_rule(struct audit_entry *e)
+{
+ int i;
+ struct audit_krule *erule = &e->rule;
+
+ /* some rules don't have associated watches */
+ if (erule->watch)
+ audit_put_watch(erule->watch);
+ if (erule->fields)
+ for (i = 0; i < erule->field_count; i++)
+ audit_free_lsm_field(&erule->fields[i]);
+ kfree(erule->fields);
+ kfree(erule->filterkey);
+ kfree(e);
+}
+
+void audit_free_rule_rcu(struct rcu_head *head)
+{
+ struct audit_entry *e = container_of(head, struct audit_entry, rcu);
+ audit_free_rule(e);
+}
+
+/* Initialize an audit filterlist entry. */
+static inline struct audit_entry *audit_init_entry(u32 field_count)
+{
+ struct audit_entry *entry;
+ struct audit_field *fields;
+
+ entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+ if (unlikely(!entry))
+ return NULL;
+
+ fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
+ if (unlikely(!fields)) {
+ kfree(entry);
+ return NULL;
+ }
+ entry->rule.fields = fields;
+
+ return entry;
+}
+
+/* Unpack a filter field's string representation from user-space
+ * buffer. */
+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;
+}
+
+/* Translate an inode field to kernel respresentation. */
+static inline int audit_to_inode(struct audit_krule *krule,
+ struct audit_field *f)
+{
+ if (krule->listnr != AUDIT_FILTER_EXIT ||
+ krule->inode_f || krule->watch || krule->tree ||
+ (f->op != Audit_equal && f->op != Audit_not_equal))
+ return -EINVAL;
+
+ krule->inode_f = f;
+ return 0;
+}
+
+static __u32 *classes[AUDIT_SYSCALL_CLASSES];
+
+int __init audit_register_class(int class, unsigned *list)
+{
+ __u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+ while (*list != ~0U) {
+ unsigned n = *list++;
+ if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
+ kfree(p);
+ return -EINVAL;
+ }
+ p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
+ }
+ if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
+ kfree(p);
+ return -EINVAL;
+ }
+ classes[class] = p;
+ return 0;
+}
+
+int audit_match_class(int class, unsigned syscall)
+{
+ if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
+ return 0;
+ if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
+ return 0;
+ return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
+}
+
+#ifdef CONFIG_AUDITSYSCALL
+static inline int audit_match_class_bits(int class, u32 *mask)
+{
+ int i;
+
+ if (classes[class]) {
+ for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
+ if (mask[i] & classes[class][i])
+ return 0;
+ }
+ return 1;
+}
+
+static int audit_match_signal(struct audit_entry *entry)
+{
+ struct audit_field *arch = entry->rule.arch_f;
+
+ if (!arch) {
+ /* When arch is unspecified, we must check both masks on biarch
+ * as syscall number alone is ambiguous. */
+ return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
+ entry->rule.mask) &&
+ audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
+ entry->rule.mask));
+ }
+
+ switch(audit_classify_arch(arch->val)) {
+ case 0: /* native */
+ return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
+ entry->rule.mask));
+ case 1: /* 32bit on biarch */
+ return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
+ entry->rule.mask));
+ default:
+ return 1;
+ }
+}
+#endif
+
+/* Common user-space to kernel rule translation. */
+static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
+{
+ unsigned listnr;
+ struct audit_entry *entry;
+ int i, err;
+
+ err = -EINVAL;
+ listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
+ switch(listnr) {
+ default:
+ goto exit_err;
+#ifdef CONFIG_AUDITSYSCALL
+ case AUDIT_FILTER_ENTRY:
+ if (rule->action == AUDIT_ALWAYS)
+ goto exit_err;
+ case AUDIT_FILTER_EXIT:
+ case AUDIT_FILTER_TASK:
+#endif
+ case AUDIT_FILTER_USER:
+ case AUDIT_FILTER_TYPE:
+ ;
+ }
+ if (unlikely(rule->action == AUDIT_POSSIBLE)) {
+ pr_err("AUDIT_POSSIBLE is deprecated\n");
+ goto exit_err;
+ }
+ if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
+ goto exit_err;
+ if (rule->field_count > AUDIT_MAX_FIELDS)
+ goto exit_err;
+
+ err = -ENOMEM;
+ entry = audit_init_entry(rule->field_count);
+ if (!entry)
+ goto exit_err;
+
+ entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
+ entry->rule.listnr = listnr;
+ entry->rule.action = rule->action;
+ entry->rule.field_count = rule->field_count;
+
+ for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
+ entry->rule.mask[i] = rule->mask[i];
+
+ for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
+ int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
+ __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
+ __u32 *class;
+
+ if (!(*p & AUDIT_BIT(bit)))
+ continue;
+ *p &= ~AUDIT_BIT(bit);
+ class = classes[i];
+ if (class) {
+ int j;
+ for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
+ entry->rule.mask[j] |= class[j];
+ }
+ }
+
+ return entry;
+
+exit_err:
+ return ERR_PTR(err);
+}
+
+static u32 audit_ops[] =
+{
+ [Audit_equal] = AUDIT_EQUAL,
+ [Audit_not_equal] = AUDIT_NOT_EQUAL,
+ [Audit_bitmask] = AUDIT_BIT_MASK,
+ [Audit_bittest] = AUDIT_BIT_TEST,
+ [Audit_lt] = AUDIT_LESS_THAN,
+ [Audit_gt] = AUDIT_GREATER_THAN,
+ [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
+ [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
+};
+
+static u32 audit_to_op(u32 op)
+{
+ u32 n;
+ for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
+ ;
+ return n;
+}
+
+/* check if an audit field is valid */
+static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
+{
+ switch(f->type) {
+ case AUDIT_MSGTYPE:
+ if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
+ entry->rule.listnr != AUDIT_FILTER_USER)
+ return -EINVAL;
+ break;
+ };
+
+ switch(f->type) {
+ default:
+ return -EINVAL;
+ case AUDIT_UID:
+ case AUDIT_EUID:
+ case AUDIT_SUID:
+ case AUDIT_FSUID:
+ case AUDIT_LOGINUID:
+ case AUDIT_OBJ_UID:
+ case AUDIT_GID:
+ case AUDIT_EGID:
+ case AUDIT_SGID:
+ case AUDIT_FSGID:
+ case AUDIT_OBJ_GID:
+ case AUDIT_PID:
+ case AUDIT_PERS:
+ case AUDIT_MSGTYPE:
+ case AUDIT_PPID:
+ case AUDIT_DEVMAJOR:
+ case AUDIT_DEVMINOR:
+ case AUDIT_EXIT:
+ case AUDIT_SUCCESS:
+ case AUDIT_INODE:
+ /* bit ops are only useful on syscall args */
+ if (f->op == Audit_bitmask || f->op == Audit_bittest)
+ return -EINVAL;
+ break;
+ case AUDIT_ARG0:
+ case AUDIT_ARG1:
+ case AUDIT_ARG2:
+ case AUDIT_ARG3:
+ case AUDIT_SUBJ_USER:
+ case AUDIT_SUBJ_ROLE:
+ case AUDIT_SUBJ_TYPE:
+ case AUDIT_SUBJ_SEN:
+ case AUDIT_SUBJ_CLR:
+ case AUDIT_OBJ_USER:
+ case AUDIT_OBJ_ROLE:
+ case AUDIT_OBJ_TYPE:
+ case AUDIT_OBJ_LEV_LOW:
+ case AUDIT_OBJ_LEV_HIGH:
+ case AUDIT_WATCH:
+ case AUDIT_DIR:
+ case AUDIT_FILTERKEY:
+ break;
+ case AUDIT_LOGINUID_SET:
+ if ((f->val != 0) && (f->val != 1))
+ return -EINVAL;
+ /* FALL THROUGH */
+ case AUDIT_ARCH:
+ if (f->op != Audit_not_equal && f->op != Audit_equal)
+ return -EINVAL;
+ break;
+ case AUDIT_PERM:
+ if (f->val & ~15)
+ return -EINVAL;
+ break;
+ case AUDIT_FILETYPE:
+ if (f->val & ~S_IFMT)
+ return -EINVAL;
+ break;
+ case AUDIT_FIELD_COMPARE:
+ if (f->val > AUDIT_MAX_FIELD_COMPARE)
+ return -EINVAL;
+ break;
+ };
+ return 0;
+}
+
+/* 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;
+ char *str;
+
+ entry = audit_to_entry_common(data);
+ if (IS_ERR(entry))
+ goto exit_nofree;
+
+ bufp = data->buf;
+ for (i = 0; i < data->field_count; i++) {
+ struct audit_field *f = &entry->rule.fields[i];
+
+ err = -EINVAL;
+
+ f->op = audit_to_op(data->fieldflags[i]);
+ if (f->op == Audit_bad)
+ goto exit_free;
+
+ f->type = data->fields[i];
+ f->val = data->values[i];
+
+ /* Support legacy tests for a valid loginuid */
+ if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
+ f->type = AUDIT_LOGINUID_SET;
+ f->val = 0;
+ entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
+ }
+
+ err = audit_field_valid(entry, f);
+ if (err)
+ goto exit_free;
+
+ err = -EINVAL;
+ switch (f->type) {
+ case AUDIT_LOGINUID:
+ case AUDIT_UID:
+ case AUDIT_EUID:
+ case AUDIT_SUID:
+ case AUDIT_FSUID:
+ case AUDIT_OBJ_UID:
+ f->uid = make_kuid(current_user_ns(), f->val);
+ if (!uid_valid(f->uid))
+ goto exit_free;
+ break;
+ case AUDIT_GID:
+ case AUDIT_EGID:
+ case AUDIT_SGID:
+ case AUDIT_FSGID:
+ case AUDIT_OBJ_GID:
+ f->gid = make_kgid(current_user_ns(), f->val);
+ if (!gid_valid(f->gid))
+ goto exit_free;
+ break;
+ case AUDIT_ARCH:
+ entry->rule.arch_f = f;
+ break;
+ case AUDIT_SUBJ_USER:
+ case AUDIT_SUBJ_ROLE:
+ case AUDIT_SUBJ_TYPE:
+ case AUDIT_SUBJ_SEN:
+ case AUDIT_SUBJ_CLR:
+ case AUDIT_OBJ_USER:
+ case AUDIT_OBJ_ROLE:
+ case AUDIT_OBJ_TYPE:
+ case AUDIT_OBJ_LEV_LOW:
+ case AUDIT_OBJ_LEV_HIGH:
+ str = audit_unpack_string(&bufp, &remain, f->val);
+ if (IS_ERR(str))
+ goto exit_free;
+ entry->rule.buflen += f->val;
+
+ err = security_audit_rule_init(f->type, f->op, str,
+ (void **)&f->lsm_rule);
+ /* Keep currently invalid fields around in case they
+ * become valid after a policy reload. */
+ if (err == -EINVAL) {
+ pr_warn("audit rule for LSM \'%s\' is invalid\n",
+ str);
+ err = 0;
+ }
+ if (err) {
+ kfree(str);
+ goto exit_free;
+ } else
+ f->lsm_str = str;
+ break;
+ case AUDIT_WATCH:
+ str = audit_unpack_string(&bufp, &remain, f->val);
+ if (IS_ERR(str))
+ goto exit_free;
+ entry->rule.buflen += f->val;
+
+ err = audit_to_watch(&entry->rule, str, f->val, f->op);
+ if (err) {
+ kfree(str);
+ goto exit_free;
+ }
+ break;
+ case AUDIT_DIR:
+ str = audit_unpack_string(&bufp, &remain, f->val);
+ if (IS_ERR(str))
+ goto exit_free;
+ entry->rule.buflen += f->val;
+
+ err = audit_make_tree(&entry->rule, str, f->op);
+ kfree(str);
+ if (err)
+ goto exit_free;
+ break;
+ case AUDIT_INODE:
+ err = audit_to_inode(&entry->rule, f);
+ if (err)
+ goto exit_free;
+ break;
+ case AUDIT_FILTERKEY:
+ if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
+ goto exit_free;
+ str = audit_unpack_string(&bufp, &remain, f->val);
+ if (IS_ERR(str))
+ goto exit_free;
+ entry->rule.buflen += f->val;
+ entry->rule.filterkey = str;
+ break;
+ }
+ }
+
+ if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
+ entry->rule.inode_f = NULL;
+
+exit_nofree:
+ return entry;
+
+exit_free:
+ if (entry->rule.watch)
+ audit_put_watch(entry->rule.watch); /* matches initial get */
+ if (entry->rule.tree)
+ audit_put_tree(entry->rule.tree); /* that's the temporary one */
+ 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, const char *str)
+{
+ size_t len = strlen(str);
+
+ memcpy(*bufp, str, len);
+ *bufp += len;
+
+ return len;
+}
+
+/* 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 NULL;
+ 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] = audit_ops[f->op];
+ switch(f->type) {
+ case AUDIT_SUBJ_USER:
+ case AUDIT_SUBJ_ROLE:
+ case AUDIT_SUBJ_TYPE:
+ case AUDIT_SUBJ_SEN:
+ case AUDIT_SUBJ_CLR:
+ case AUDIT_OBJ_USER:
+ case AUDIT_OBJ_ROLE:
+ case AUDIT_OBJ_TYPE:
+ case AUDIT_OBJ_LEV_LOW:
+ case AUDIT_OBJ_LEV_HIGH:
+ data->buflen += data->values[i] =
+ audit_pack_string(&bufp, f->lsm_str);
+ break;
+ case AUDIT_WATCH:
+ data->buflen += data->values[i] =
+ audit_pack_string(&bufp,
+ audit_watch_path(krule->watch));
+ break;
+ case AUDIT_DIR:
+ data->buflen += data->values[i] =
+ audit_pack_string(&bufp,
+ audit_tree_path(krule->tree));
+ break;
+ case AUDIT_FILTERKEY:
+ data->buflen += data->values[i] =
+ audit_pack_string(&bufp, krule->filterkey);
+ break;
+ case AUDIT_LOGINUID_SET:
+ if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
+ data->fields[i] = AUDIT_LOGINUID;
+ data->values[i] = AUDIT_UID_UNSET;
+ break;
+ }
+ /* fallthrough if set */
+ 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->pflags != b->pflags ||
+ 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) {
+ case AUDIT_SUBJ_USER:
+ case AUDIT_SUBJ_ROLE:
+ case AUDIT_SUBJ_TYPE:
+ case AUDIT_SUBJ_SEN:
+ case AUDIT_SUBJ_CLR:
+ case AUDIT_OBJ_USER:
+ case AUDIT_OBJ_ROLE:
+ case AUDIT_OBJ_TYPE:
+ case AUDIT_OBJ_LEV_LOW:
+ case AUDIT_OBJ_LEV_HIGH:
+ if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
+ return 1;
+ break;
+ case AUDIT_WATCH:
+ if (strcmp(audit_watch_path(a->watch),
+ audit_watch_path(b->watch)))
+ return 1;
+ break;
+ case AUDIT_DIR:
+ if (strcmp(audit_tree_path(a->tree),
+ audit_tree_path(b->tree)))
+ return 1;
+ break;
+ case AUDIT_FILTERKEY:
+ /* both filterkeys exist based on above type compare */
+ if (strcmp(a->filterkey, b->filterkey))
+ return 1;
+ break;
+ case AUDIT_UID:
+ case AUDIT_EUID:
+ case AUDIT_SUID:
+ case AUDIT_FSUID:
+ case AUDIT_LOGINUID:
+ case AUDIT_OBJ_UID:
+ if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
+ return 1;
+ break;
+ case AUDIT_GID:
+ case AUDIT_EGID:
+ case AUDIT_SGID:
+ case AUDIT_FSGID:
+ case AUDIT_OBJ_GID:
+ if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
+ return 1;
+ break;
+ 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;
+}
+
+/* Duplicate LSM field information. The lsm_rule is opaque, so must be
+ * re-initialized. */
+static inline int audit_dupe_lsm_field(struct audit_field *df,
+ struct audit_field *sf)
+{
+ int ret = 0;
+ char *lsm_str;
+
+ /* our own copy of lsm_str */
+ lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
+ if (unlikely(!lsm_str))
+ return -ENOMEM;
+ df->lsm_str = lsm_str;
+
+ /* our own (refreshed) copy of lsm_rule */
+ ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
+ (void **)&df->lsm_rule);
+ /* Keep currently invalid fields around in case they
+ * become valid after a policy reload. */
+ if (ret == -EINVAL) {
+ pr_warn("audit rule for LSM \'%s\' is invalid\n",
+ df->lsm_str);
+ ret = 0;
+ }
+
+ return ret;
+}
+
+/* Duplicate an audit rule. This will be a deep copy with the exception
+ * of the watch - that pointer is carried over. The LSM specific fields
+ * will be updated in the copy. The point is to be able to replace the old
+ * rule with the new rule in the filterlist, then free the old rule.
+ * The rlist element is undefined; list manipulations are handled apart from
+ * the initial copy. */
+struct audit_entry *audit_dupe_rule(struct audit_krule *old)
+{
+ u32 fcount = old->field_count;
+ struct audit_entry *entry;
+ struct audit_krule *new;
+ char *fk;
+ int i, err = 0;
+
+ entry = audit_init_entry(fcount);
+ if (unlikely(!entry))
+ return ERR_PTR(-ENOMEM);
+
+ new = &entry->rule;
+ new->flags = old->flags;
+ new->pflags = old->pflags;
+ new->listnr = old->listnr;
+ new->action = old->action;
+ for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
+ new->mask[i] = old->mask[i];
+ new->prio = old->prio;
+ new->buflen = old->buflen;
+ new->inode_f = old->inode_f;
+ new->field_count = old->field_count;
+
+ /*
+ * note that we are OK with not refcounting here; audit_match_tree()
+ * never dereferences tree and we can't get false positives there
+ * since we'd have to have rule gone from the list *and* removed
+ * before the chunks found by lookup had been allocated, i.e. before
+ * the beginning of list scan.
+ */
+ new->tree = old->tree;
+ memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
+
+ /* deep copy this information, updating the lsm_rule fields, because
+ * the originals will all be freed when the old rule is freed. */
+ for (i = 0; i < fcount; i++) {
+ switch (new->fields[i].type) {
+ case AUDIT_SUBJ_USER:
+ case AUDIT_SUBJ_ROLE:
+ case AUDIT_SUBJ_TYPE:
+ case AUDIT_SUBJ_SEN:
+ case AUDIT_SUBJ_CLR:
+ case AUDIT_OBJ_USER:
+ case AUDIT_OBJ_ROLE:
+ case AUDIT_OBJ_TYPE:
+ case AUDIT_OBJ_LEV_LOW:
+ case AUDIT_OBJ_LEV_HIGH:
+ err = audit_dupe_lsm_field(&new->fields[i],
+ &old->fields[i]);
+ break;
+ case AUDIT_FILTERKEY:
+ fk = kstrdup(old->filterkey, GFP_KERNEL);
+ if (unlikely(!fk))
+ err = -ENOMEM;
+ else
+ new->filterkey = fk;
+ }
+ if (err) {
+ audit_free_rule(entry);
+ return ERR_PTR(err);
+ }
+ }
+
+ if (old->watch) {
+ audit_get_watch(old->watch);
+ new->watch = old->watch;
+ }
+
+ return entry;
+}
+
+/* Find an existing audit rule.
+ * Caller must hold audit_filter_mutex to prevent stale rule data. */
+static struct audit_entry *audit_find_rule(struct audit_entry *entry,
+ struct list_head **p)
+{
+ struct audit_entry *e, *found = NULL;
+ struct list_head *list;
+ int h;
+
+ if (entry->rule.inode_f) {
+ h = audit_hash_ino(entry->rule.inode_f->val);
+ *p = list = &audit_inode_hash[h];
+ } else if (entry->rule.watch) {
+ /* we don't know the inode number, so must walk entire hash */
+ for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
+ list = &audit_inode_hash[h];
+ list_for_each_entry(e, list, list)
+ if (!audit_compare_rule(&entry->rule, &e->rule)) {
+ found = e;
+ goto out;
+ }
+ }
+ goto out;
+ } else {
+ *p = list = &audit_filter_list[entry->rule.listnr];
+ }
+
+ list_for_each_entry(e, list, list)
+ if (!audit_compare_rule(&entry->rule, &e->rule)) {
+ found = e;
+ goto out;
+ }
+
+out:
+ return found;
+}
+
+static u64 prio_low = ~0ULL/2;
+static u64 prio_high = ~0ULL/2 - 1;
+
+/* Add rule to given filterlist if not a duplicate. */
+static inline int audit_add_rule(struct audit_entry *entry)
+{
+ struct audit_entry *e;
+ struct audit_watch *watch = entry->rule.watch;
+ struct audit_tree *tree = entry->rule.tree;
+ struct list_head *list;
+ int err;
+#ifdef CONFIG_AUDITSYSCALL
+ int dont_count = 0;
+
+ /* If either of these, don't count towards total */
+ if (entry->rule.listnr == AUDIT_FILTER_USER ||
+ entry->rule.listnr == AUDIT_FILTER_TYPE)
+ dont_count = 1;
+#endif
+
+ mutex_lock(&audit_filter_mutex);
+ e = audit_find_rule(entry, &list);
+ if (e) {
+ mutex_unlock(&audit_filter_mutex);
+ err = -EEXIST;
+ /* normally audit_add_tree_rule() will free it on failure */
+ if (tree)
+ audit_put_tree(tree);
+ goto error;
+ }
+
+ if (watch) {
+ /* audit_filter_mutex is dropped and re-taken during this call */
+ err = audit_add_watch(&entry->rule, &list);
+ if (err) {
+ mutex_unlock(&audit_filter_mutex);
+ /*
+ * normally audit_add_tree_rule() will free it
+ * on failure
+ */
+ if (tree)
+ audit_put_tree(tree);
+ goto error;
+ }
+ }
+ if (tree) {
+ err = audit_add_tree_rule(&entry->rule);
+ if (err) {
+ mutex_unlock(&audit_filter_mutex);
+ goto error;
+ }
+ }
+
+ entry->rule.prio = ~0ULL;
+ if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
+ if (entry->rule.flags & AUDIT_FILTER_PREPEND)
+ entry->rule.prio = ++prio_high;
+ else
+ entry->rule.prio = --prio_low;
+ }
+
+ if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
+ list_add(&entry->rule.list,
+ &audit_rules_list[entry->rule.listnr]);
+ list_add_rcu(&entry->list, list);
+ entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
+ } else {
+ list_add_tail(&entry->rule.list,
+ &audit_rules_list[entry->rule.listnr]);
+ list_add_tail_rcu(&entry->list, list);
+ }
+#ifdef CONFIG_AUDITSYSCALL
+ if (!dont_count)
+ audit_n_rules++;
+
+ if (!audit_match_signal(entry))
+ audit_signals++;
+#endif
+ mutex_unlock(&audit_filter_mutex);
+
+ return 0;
+
+error:
+ if (watch)
+ audit_put_watch(watch); /* tmp watch, matches initial get */
+ return err;
+}
+
+/* Remove an existing rule from filterlist. */
+static inline int audit_del_rule(struct audit_entry *entry)
+{
+ struct audit_entry *e;
+ struct audit_watch *watch = entry->rule.watch;
+ struct audit_tree *tree = entry->rule.tree;
+ struct list_head *list;
+ int ret = 0;
+#ifdef CONFIG_AUDITSYSCALL
+ int dont_count = 0;
+
+ /* If either of these, don't count towards total */
+ if (entry->rule.listnr == AUDIT_FILTER_USER ||
+ entry->rule.listnr == AUDIT_FILTER_TYPE)
+ dont_count = 1;
+#endif
+
+ mutex_lock(&audit_filter_mutex);
+ e = audit_find_rule(entry, &list);
+ if (!e) {
+ mutex_unlock(&audit_filter_mutex);
+ ret = -ENOENT;
+ goto out;
+ }
+
+ if (e->rule.watch)
+ audit_remove_watch_rule(&e->rule);
+
+ if (e->rule.tree)
+ audit_remove_tree_rule(&e->rule);
+
+ list_del_rcu(&e->list);
+ list_del(&e->rule.list);
+ call_rcu(&e->rcu, audit_free_rule_rcu);
+
+#ifdef CONFIG_AUDITSYSCALL
+ if (!dont_count)
+ audit_n_rules--;
+
+ if (!audit_match_signal(entry))
+ audit_signals--;
+#endif
+ mutex_unlock(&audit_filter_mutex);
+
+out:
+ if (watch)
+ audit_put_watch(watch); /* match initial get */
+ if (tree)
+ audit_put_tree(tree); /* that's the temporary one */
+
+ return ret;
+}
+
+/* List rules using struct audit_rule_data. */
+static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
+{
+ struct sk_buff *skb;
+ struct audit_krule *r;
+ int i;
+
+ /* This is a blocking read, so use audit_filter_mutex instead of rcu
+ * iterator to sync with list writers. */
+ for (i=0; i<AUDIT_NR_FILTERS; i++) {
+ list_for_each_entry(r, &audit_rules_list[i], list) {
+ struct audit_rule_data *data;
+
+ data = audit_krule_to_data(r);
+ if (unlikely(!data))
+ break;
+ skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
+ 0, 1, data,
+ sizeof(*data) + data->buflen);
+ if (skb)
+ skb_queue_tail(q, skb);
+ kfree(data);
+ }
+ }
+ skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
+ if (skb)
+ skb_queue_tail(q, skb);
+}
+
+/* Log rule additions and removals */
+static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
+{
+ struct audit_buffer *ab;
+ uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
+ unsigned int sessionid = audit_get_sessionid(current);
+
+ if (!audit_enabled)
+ return;
+
+ ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+ if (!ab)
+ return;
+ audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
+ audit_log_task_context(ab);
+ audit_log_format(ab, " op=");
+ audit_log_string(ab, action);
+ audit_log_key(ab, rule->filterkey);
+ audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
+ audit_log_end(ab);
+}
+
+/**
+ * audit_rule_change - apply all rules to the specified message type
+ * @type: audit message type
+ * @portid: target port id for netlink audit messages
+ * @seq: netlink audit message sequence (serial) number
+ * @data: payload data
+ * @datasz: size of payload data
+ */
+int audit_rule_change(int type, __u32 portid, int seq, void *data,
+ size_t datasz)
+{
+ int err = 0;
+ struct audit_entry *entry;
+
+ entry = audit_data_to_entry(data, datasz);
+ if (IS_ERR(entry))
+ return PTR_ERR(entry);
+
+ switch (type) {
+ case AUDIT_ADD_RULE:
+ err = audit_add_rule(entry);
+ audit_log_rule_change("add_rule", &entry->rule, !err);
+ break;
+ case AUDIT_DEL_RULE:
+ err = audit_del_rule(entry);
+ audit_log_rule_change("remove_rule", &entry->rule, !err);
+ break;
+ default:
+ err = -EINVAL;
+ WARN_ON(1);
+ }
+
+ if (err || type == AUDIT_DEL_RULE)
+ audit_free_rule(entry);
+
+ return err;
+}
+
+/**
+ * audit_list_rules_send - list the audit rules
+ * @request_skb: skb of request we are replying to (used to target the reply)
+ * @seq: netlink audit message sequence (serial) number
+ */
+int audit_list_rules_send(struct sk_buff *request_skb, int seq)
+{
+ u32 portid = NETLINK_CB(request_skb).portid;
+ struct net *net = sock_net(NETLINK_CB(request_skb).sk);
+ struct task_struct *tsk;
+ struct audit_netlink_list *dest;
+ int err = 0;
+
+ /* 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(sizeof(struct audit_netlink_list), GFP_KERNEL);
+ if (!dest)
+ return -ENOMEM;
+ dest->net = get_net(net);
+ dest->portid = portid;
+ skb_queue_head_init(&dest->q);
+
+ mutex_lock(&audit_filter_mutex);
+ audit_list_rules(portid, seq, &dest->q);
+ mutex_unlock(&audit_filter_mutex);
+
+ tsk = kthread_run(audit_send_list, dest, "audit_send_list");
+ if (IS_ERR(tsk)) {
+ skb_queue_purge(&dest->q);
+ kfree(dest);
+ err = PTR_ERR(tsk);
+ }
+
+ return err;
+}
+
+int audit_comparator(u32 left, u32 op, u32 right)
+{
+ switch (op) {
+ case Audit_equal:
+ return (left == right);
+ case Audit_not_equal:
+ return (left != right);
+ case Audit_lt:
+ return (left < right);
+ case Audit_le:
+ return (left <= right);
+ case Audit_gt:
+ return (left > right);
+ case Audit_ge:
+ return (left >= right);
+ case Audit_bitmask:
+ return (left & right);
+ case Audit_bittest:
+ return ((left & right) == right);
+ default:
+ BUG();
+ return 0;
+ }
+}
+
+int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
+{
+ switch (op) {
+ case Audit_equal:
+ return uid_eq(left, right);
+ case Audit_not_equal:
+ return !uid_eq(left, right);
+ case Audit_lt:
+ return uid_lt(left, right);
+ case Audit_le:
+ return uid_lte(left, right);
+ case Audit_gt:
+ return uid_gt(left, right);
+ case Audit_ge:
+ return uid_gte(left, right);
+ case Audit_bitmask:
+ case Audit_bittest:
+ default:
+ BUG();
+ return 0;
+ }
+}
+
+int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
+{
+ switch (op) {
+ case Audit_equal:
+ return gid_eq(left, right);
+ case Audit_not_equal:
+ return !gid_eq(left, right);
+ case Audit_lt:
+ return gid_lt(left, right);
+ case Audit_le:
+ return gid_lte(left, right);
+ case Audit_gt:
+ return gid_gt(left, right);
+ case Audit_ge:
+ return gid_gte(left, right);
+ case Audit_bitmask:
+ case Audit_bittest:
+ default:
+ BUG();
+ return 0;
+ }
+}
+
+/**
+ * parent_len - find the length of the parent portion of a pathname
+ * @path: pathname of which to determine length
+ */
+int parent_len(const char *path)
+{
+ int plen;
+ const char *p;
+
+ plen = strlen(path);
+
+ if (plen == 0)
+ return plen;
+
+ /* disregard trailing slashes */
+ p = path + plen - 1;
+ while ((*p == '/') && (p > path))
+ p--;
+
+ /* walk backward until we find the next slash or hit beginning */
+ while ((*p != '/') && (p > path))
+ p--;
+
+ /* did we find a slash? Then increment to include it in path */
+ if (*p == '/')
+ p++;
+
+ return p - path;
+}
+
+/**
+ * audit_compare_dname_path - compare given dentry name with last component in
+ * given path. Return of 0 indicates a match.
+ * @dname: dentry name that we're comparing
+ * @path: full pathname that we're comparing
+ * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
+ * here indicates that we must compute this value.
+ */
+int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
+{
+ int dlen, pathlen;
+ const char *p;
+
+ dlen = strlen(dname);
+ pathlen = strlen(path);
+ if (pathlen < dlen)
+ return 1;
+
+ parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
+ if (pathlen - parentlen != dlen)
+ return 1;
+
+ p = path + parentlen;
+
+ return strncmp(p, dname, dlen);
+}
+
+static int audit_filter_user_rules(struct audit_krule *rule, int type,
+ enum audit_state *state)
+{
+ int i;
+
+ for (i = 0; i < rule->field_count; i++) {
+ struct audit_field *f = &rule->fields[i];
+ pid_t pid;
+ int result = 0;
+ u32 sid;
+
+ switch (f->type) {
+ case AUDIT_PID:
+ pid = task_pid_nr(current);
+ result = audit_comparator(pid, f->op, f->val);
+ break;
+ case AUDIT_UID:
+ result = audit_uid_comparator(current_uid(), f->op, f->uid);
+ break;
+ case AUDIT_GID:
+ result = audit_gid_comparator(current_gid(), f->op, f->gid);
+ break;
+ case AUDIT_LOGINUID:
+ result = audit_uid_comparator(audit_get_loginuid(current),
+ f->op, f->uid);
+ break;
+ case AUDIT_LOGINUID_SET:
+ result = audit_comparator(audit_loginuid_set(current),
+ f->op, f->val);
+ break;
+ case AUDIT_MSGTYPE:
+ result = audit_comparator(type, f->op, f->val);
+ break;
+ case AUDIT_SUBJ_USER:
+ case AUDIT_SUBJ_ROLE:
+ case AUDIT_SUBJ_TYPE:
+ case AUDIT_SUBJ_SEN:
+ case AUDIT_SUBJ_CLR:
+ if (f->lsm_rule) {
+ security_task_getsecid(current, &sid);
+ result = security_audit_rule_match(sid,
+ f->type,
+ f->op,
+ f->lsm_rule,
+ NULL);
+ }
+ break;
+ }
+
+ if (!result)
+ return 0;
+ }
+ switch (rule->action) {
+ case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
+ case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
+ }
+ return 1;
+}
+
+int audit_filter_user(int type)
+{
+ enum audit_state state = AUDIT_DISABLED;
+ struct audit_entry *e;
+ int rc, ret;
+
+ ret = 1; /* Audit by default */
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
+ rc = audit_filter_user_rules(&e->rule, type, &state);
+ if (rc) {
+ if (rc > 0 && state == AUDIT_DISABLED)
+ ret = 0;
+ break;
+ }
+ }
+ rcu_read_unlock();
+
+ return ret;
+}
+
+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;
+}
+
+static int update_lsm_rule(struct audit_krule *r)
+{
+ struct audit_entry *entry = container_of(r, struct audit_entry, rule);
+ struct audit_entry *nentry;
+ int err = 0;
+
+ if (!security_audit_rule_known(r))
+ return 0;
+
+ nentry = audit_dupe_rule(r);
+ if (IS_ERR(nentry)) {
+ /* save the first error encountered for the
+ * return value */
+ err = PTR_ERR(nentry);
+ audit_panic("error updating LSM filters");
+ if (r->watch)
+ list_del(&r->rlist);
+ list_del_rcu(&entry->list);
+ list_del(&r->list);
+ } else {
+ if (r->watch || r->tree)
+ list_replace_init(&r->rlist, &nentry->rule.rlist);
+ list_replace_rcu(&entry->list, &nentry->list);
+ list_replace(&r->list, &nentry->rule.list);
+ }
+ call_rcu(&entry->rcu, audit_free_rule_rcu);
+
+ return err;
+}
+
+/* This function will re-initialize the lsm_rule field of all applicable rules.
+ * It will traverse the filter lists serarching for rules that contain LSM
+ * specific filter fields. When such a rule is found, it is copied, the
+ * LSM field is re-initialized, and the old rule is replaced with the
+ * updated rule. */
+int audit_update_lsm_rules(void)
+{
+ struct audit_krule *r, *n;
+ int i, err = 0;
+
+ /* audit_filter_mutex synchronizes the writers */
+ mutex_lock(&audit_filter_mutex);
+
+ for (i = 0; i < AUDIT_NR_FILTERS; i++) {
+ list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
+ int res = update_lsm_rule(r);
+ if (!err)
+ err = res;
+ }
+ }
+ mutex_unlock(&audit_filter_mutex);
+
+ return err;
+}
Code Review / kvmfornfv.git / blobdiff