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![Ingo Molnar](/assets/img/avatar_default.png)
Semaphore to mutex conversion. The conversion was generated via scripts, and the result was validated automatically via a script as well. Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
630 lines
15 KiB
C
630 lines
15 KiB
C
/* auditfilter.c -- filtering of audit events
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*
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* Copyright 2003-2004 Red Hat, Inc.
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* Copyright 2005 Hewlett-Packard Development Company, L.P.
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* Copyright 2005 IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/kernel.h>
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#include <linux/audit.h>
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#include <linux/kthread.h>
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#include <linux/netlink.h>
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#include "audit.h"
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/* There are three lists of rules -- one to search at task creation
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* time, one to search at syscall entry time, and another to search at
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* syscall exit time. */
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struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
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LIST_HEAD_INIT(audit_filter_list[0]),
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LIST_HEAD_INIT(audit_filter_list[1]),
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LIST_HEAD_INIT(audit_filter_list[2]),
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LIST_HEAD_INIT(audit_filter_list[3]),
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LIST_HEAD_INIT(audit_filter_list[4]),
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LIST_HEAD_INIT(audit_filter_list[5]),
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#if AUDIT_NR_FILTERS != 6
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#error Fix audit_filter_list initialiser
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#endif
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};
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static inline void audit_free_rule(struct audit_entry *e)
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{
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kfree(e->rule.fields);
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kfree(e);
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}
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static inline void audit_free_rule_rcu(struct rcu_head *head)
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{
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struct audit_entry *e = container_of(head, struct audit_entry, rcu);
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audit_free_rule(e);
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}
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/* Unpack a filter field's string representation from user-space
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* buffer. */
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static __attribute__((unused)) char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
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{
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char *str;
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if (!*bufp || (len == 0) || (len > *remain))
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return ERR_PTR(-EINVAL);
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/* Of the currently implemented string fields, PATH_MAX
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* defines the longest valid length.
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*/
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if (len > PATH_MAX)
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return ERR_PTR(-ENAMETOOLONG);
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str = kmalloc(len + 1, GFP_KERNEL);
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if (unlikely(!str))
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return ERR_PTR(-ENOMEM);
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memcpy(str, *bufp, len);
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str[len] = 0;
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*bufp += len;
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*remain -= len;
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return str;
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}
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/* Common user-space to kernel rule translation. */
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static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
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{
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unsigned listnr;
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struct audit_entry *entry;
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struct audit_field *fields;
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int i, err;
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err = -EINVAL;
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listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
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switch(listnr) {
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default:
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goto exit_err;
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case AUDIT_FILTER_USER:
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case AUDIT_FILTER_TYPE:
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#ifdef CONFIG_AUDITSYSCALL
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case AUDIT_FILTER_ENTRY:
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case AUDIT_FILTER_EXIT:
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case AUDIT_FILTER_TASK:
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#endif
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;
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}
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if (rule->action != AUDIT_NEVER && rule->action != AUDIT_POSSIBLE &&
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rule->action != AUDIT_ALWAYS)
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goto exit_err;
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if (rule->field_count > AUDIT_MAX_FIELDS)
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goto exit_err;
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err = -ENOMEM;
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entry = kmalloc(sizeof(*entry), GFP_KERNEL);
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if (unlikely(!entry))
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goto exit_err;
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fields = kmalloc(sizeof(*fields) * rule->field_count, GFP_KERNEL);
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if (unlikely(!fields)) {
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kfree(entry);
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goto exit_err;
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}
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memset(&entry->rule, 0, sizeof(struct audit_krule));
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memset(fields, 0, sizeof(struct audit_field));
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entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
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entry->rule.listnr = listnr;
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entry->rule.action = rule->action;
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entry->rule.field_count = rule->field_count;
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entry->rule.fields = fields;
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for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
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entry->rule.mask[i] = rule->mask[i];
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return entry;
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exit_err:
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return ERR_PTR(err);
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}
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/* Translate struct audit_rule to kernel's rule respresentation.
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* Exists for backward compatibility with userspace. */
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static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
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{
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struct audit_entry *entry;
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int err = 0;
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int i;
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entry = audit_to_entry_common(rule);
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if (IS_ERR(entry))
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goto exit_nofree;
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for (i = 0; i < rule->field_count; i++) {
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struct audit_field *f = &entry->rule.fields[i];
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if (rule->fields[i] & AUDIT_UNUSED_BITS) {
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err = -EINVAL;
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goto exit_free;
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}
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f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
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f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
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f->val = rule->values[i];
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entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;
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/* Support for legacy operators where
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* AUDIT_NEGATE bit signifies != and otherwise assumes == */
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if (f->op & AUDIT_NEGATE)
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f->op = AUDIT_NOT_EQUAL;
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else if (!f->op)
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f->op = AUDIT_EQUAL;
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else if (f->op == AUDIT_OPERATORS) {
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err = -EINVAL;
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goto exit_free;
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}
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}
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exit_nofree:
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return entry;
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exit_free:
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audit_free_rule(entry);
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return ERR_PTR(err);
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}
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/* Translate struct audit_rule_data to kernel's rule respresentation. */
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static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
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size_t datasz)
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{
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int err = 0;
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struct audit_entry *entry;
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void *bufp;
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/* size_t remain = datasz - sizeof(struct audit_rule_data); */
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int i;
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entry = audit_to_entry_common((struct audit_rule *)data);
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if (IS_ERR(entry))
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goto exit_nofree;
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bufp = data->buf;
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entry->rule.vers_ops = 2;
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for (i = 0; i < data->field_count; i++) {
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struct audit_field *f = &entry->rule.fields[i];
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err = -EINVAL;
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if (!(data->fieldflags[i] & AUDIT_OPERATORS) ||
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data->fieldflags[i] & ~AUDIT_OPERATORS)
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goto exit_free;
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f->op = data->fieldflags[i] & AUDIT_OPERATORS;
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f->type = data->fields[i];
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switch(f->type) {
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/* call type-specific conversion routines here */
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default:
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f->val = data->values[i];
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}
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}
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exit_nofree:
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return entry;
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exit_free:
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audit_free_rule(entry);
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return ERR_PTR(err);
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}
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/* Pack a filter field's string representation into data block. */
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static inline size_t audit_pack_string(void **bufp, char *str)
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{
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size_t len = strlen(str);
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memcpy(*bufp, str, len);
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*bufp += len;
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return len;
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}
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/* Translate kernel rule respresentation to struct audit_rule.
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* Exists for backward compatibility with userspace. */
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static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
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{
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struct audit_rule *rule;
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int i;
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rule = kmalloc(sizeof(*rule), GFP_KERNEL);
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if (unlikely(!rule))
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return ERR_PTR(-ENOMEM);
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memset(rule, 0, sizeof(*rule));
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rule->flags = krule->flags | krule->listnr;
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rule->action = krule->action;
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rule->field_count = krule->field_count;
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for (i = 0; i < rule->field_count; i++) {
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rule->values[i] = krule->fields[i].val;
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rule->fields[i] = krule->fields[i].type;
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if (krule->vers_ops == 1) {
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if (krule->fields[i].op & AUDIT_NOT_EQUAL)
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rule->fields[i] |= AUDIT_NEGATE;
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} else {
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rule->fields[i] |= krule->fields[i].op;
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}
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}
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for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
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return rule;
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}
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/* Translate kernel rule respresentation to struct audit_rule_data. */
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static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
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{
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struct audit_rule_data *data;
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void *bufp;
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int i;
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data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
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if (unlikely(!data))
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return ERR_PTR(-ENOMEM);
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memset(data, 0, sizeof(*data));
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data->flags = krule->flags | krule->listnr;
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data->action = krule->action;
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data->field_count = krule->field_count;
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bufp = data->buf;
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for (i = 0; i < data->field_count; i++) {
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struct audit_field *f = &krule->fields[i];
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data->fields[i] = f->type;
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data->fieldflags[i] = f->op;
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switch(f->type) {
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/* call type-specific conversion routines here */
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default:
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data->values[i] = f->val;
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}
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}
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for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
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return data;
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}
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/* Compare two rules in kernel format. Considered success if rules
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* don't match. */
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static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
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{
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int i;
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if (a->flags != b->flags ||
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a->listnr != b->listnr ||
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a->action != b->action ||
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a->field_count != b->field_count)
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return 1;
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for (i = 0; i < a->field_count; i++) {
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if (a->fields[i].type != b->fields[i].type ||
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a->fields[i].op != b->fields[i].op)
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return 1;
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switch(a->fields[i].type) {
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/* call type-specific comparison routines here */
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default:
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if (a->fields[i].val != b->fields[i].val)
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return 1;
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}
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}
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for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
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if (a->mask[i] != b->mask[i])
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return 1;
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return 0;
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}
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/* Add rule to given filterlist if not a duplicate. Protected by
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* audit_netlink_mutex. */
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static inline int audit_add_rule(struct audit_entry *entry,
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struct list_head *list)
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{
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struct audit_entry *e;
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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(e, list, list) {
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if (!audit_compare_rule(&entry->rule, &e->rule))
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return -EEXIST;
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}
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if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
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list_add_rcu(&entry->list, list);
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} else {
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list_add_tail_rcu(&entry->list, list);
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}
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return 0;
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}
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/* Remove an existing rule from filterlist. Protected by
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* audit_netlink_mutex. */
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static inline int audit_del_rule(struct audit_entry *entry,
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struct list_head *list)
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{
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struct audit_entry *e;
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/* Do not use the _rcu iterator here, since this is the only
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* deletion routine. */
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list_for_each_entry(e, list, list) {
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if (!audit_compare_rule(&entry->rule, &e->rule)) {
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list_del_rcu(&e->list);
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call_rcu(&e->rcu, audit_free_rule_rcu);
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return 0;
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}
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}
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return -ENOENT; /* No matching rule */
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}
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/* List rules using struct audit_rule. Exists for backward
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* compatibility with userspace. */
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static int audit_list(void *_dest)
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{
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int pid, seq;
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int *dest = _dest;
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struct audit_entry *entry;
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int i;
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pid = dest[0];
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seq = dest[1];
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kfree(dest);
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mutex_lock(&audit_netlink_mutex);
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/* The *_rcu iterators not needed here because we are
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always called with audit_netlink_mutex held. */
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for (i=0; i<AUDIT_NR_FILTERS; i++) {
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list_for_each_entry(entry, &audit_filter_list[i], list) {
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struct audit_rule *rule;
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rule = audit_krule_to_rule(&entry->rule);
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if (unlikely(!rule))
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break;
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audit_send_reply(pid, seq, AUDIT_LIST, 0, 1,
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rule, sizeof(*rule));
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kfree(rule);
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}
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}
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audit_send_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
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mutex_unlock(&audit_netlink_mutex);
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return 0;
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}
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/* List rules using struct audit_rule_data. */
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static int audit_list_rules(void *_dest)
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{
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int pid, seq;
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int *dest = _dest;
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struct audit_entry *e;
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int i;
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pid = dest[0];
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seq = dest[1];
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kfree(dest);
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mutex_lock(&audit_netlink_mutex);
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/* The *_rcu iterators not needed here because we are
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always called with audit_netlink_mutex held. */
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for (i=0; i<AUDIT_NR_FILTERS; i++) {
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list_for_each_entry(e, &audit_filter_list[i], list) {
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struct audit_rule_data *data;
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data = audit_krule_to_data(&e->rule);
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if (unlikely(!data))
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break;
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audit_send_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
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data, sizeof(*data));
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kfree(data);
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}
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}
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audit_send_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
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mutex_unlock(&audit_netlink_mutex);
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return 0;
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}
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/**
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* audit_receive_filter - apply all rules to the specified message type
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* @type: audit message type
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* @pid: target pid for netlink audit messages
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* @uid: target uid for netlink audit messages
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* @seq: netlink audit message sequence (serial) number
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* @data: payload data
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* @datasz: size of payload data
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* @loginuid: loginuid of sender
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*/
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int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
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size_t datasz, uid_t loginuid)
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{
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struct task_struct *tsk;
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int *dest;
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int err = 0;
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struct audit_entry *entry;
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switch (type) {
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case AUDIT_LIST:
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case AUDIT_LIST_RULES:
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/* We can't just spew out the rules here because we might fill
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* the available socket buffer space and deadlock waiting for
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* auditctl to read from it... which isn't ever going to
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* happen if we're actually running in the context of auditctl
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* trying to _send_ the stuff */
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dest = kmalloc(2 * sizeof(int), GFP_KERNEL);
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if (!dest)
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return -ENOMEM;
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dest[0] = pid;
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dest[1] = seq;
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if (type == AUDIT_LIST)
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tsk = kthread_run(audit_list, dest, "audit_list");
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else
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tsk = kthread_run(audit_list_rules, dest,
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"audit_list_rules");
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if (IS_ERR(tsk)) {
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kfree(dest);
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err = PTR_ERR(tsk);
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}
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break;
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case AUDIT_ADD:
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case AUDIT_ADD_RULE:
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if (type == AUDIT_ADD)
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entry = audit_rule_to_entry(data);
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else
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entry = audit_data_to_entry(data, datasz);
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if (IS_ERR(entry))
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return PTR_ERR(entry);
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err = audit_add_rule(entry,
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&audit_filter_list[entry->rule.listnr]);
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audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
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"auid=%u add rule to list=%d res=%d\n",
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loginuid, entry->rule.listnr, !err);
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if (err)
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audit_free_rule(entry);
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break;
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case AUDIT_DEL:
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case AUDIT_DEL_RULE:
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if (type == AUDIT_DEL)
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entry = audit_rule_to_entry(data);
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else
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entry = audit_data_to_entry(data, datasz);
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if (IS_ERR(entry))
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return PTR_ERR(entry);
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|
|
|
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;
|
|
}
|