lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

[PATCH] add rule filterkey

Browse Source 
Add support for a rule key, which can be used to tie audit records to audit
rules.  This is useful when a watched file is accessed through a link or
symlink, as well as for general audit log analysis.

Because this patch uses a string key instead of an integer key, there is a bit
of extra overhead to do the kstrdup() when a rule fires.  However, we're also
allocating memory for the audit record buffer, so it's probably not that
significant.  I went ahead with a string key because it seems more
user-friendly.

Note that the user must ensure that filterkeys are unique.  The kernel only
checks for duplicate rules.

Signed-off-by: Amy Griffis <amy.griffis@hpd.com>
This commit is contained in:
Amy Griffis
2006-06-14 18:45:21 -04:00
committed by Al Viro
parent 9262e9149f
commit 5adc8a6adc
4 changed files with 78 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

95
kernel/auditfilter.c
View File

@@ -141,6 +141,7 @@ static inline void audit_free_rule(struct audit_entry *e)
selinux_audit_rule_free(f->se_rule);
}
kfree(e->rule.fields);
kfree(e->rule.filterkey);
kfree(e);
}
@@ -511,6 +512,16 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
if (err)
goto exit_free;
break;
case AUDIT_FILTERKEY:
err = -EINVAL;
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;
default:
goto exit_free;
}
@@ -612,6 +623,10 @@ static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
data->buflen += data->values[i] =
audit_pack_string(&bufp, krule->watch->path);
break;
case AUDIT_FILTERKEY:
data->buflen += data->values[i] =
audit_pack_string(&bufp, krule->filterkey);
break;
default:
data->values[i] = f->val;
}
@@ -651,6 +666,11 @@ static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
if (strcmp(a->watch->path, b->watch->path))
return 1;
break;
case AUDIT_FILTERKEY:
/* both filterkeys exist based on above type compare */
if (strcmp(a->filterkey, b->filterkey))
return 1;
break;
default:
if (a->fields[i].val != b->fields[i].val)
return 1;
@@ -730,6 +750,7 @@ static 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);
@@ -760,6 +781,13 @@ static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
case AUDIT_SE_CLR:
err = audit_dupe_selinux_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);
@@ -1245,6 +1273,34 @@ static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
skb_queue_tail(q, skb);
}
/* Log rule additions and removals */
static void audit_log_rule_change(uid_t loginuid, u32 sid, char *action,
struct audit_krule *rule, int res)
{
struct audit_buffer *ab;
ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
if (!ab)
return;
audit_log_format(ab, "auid=%u", loginuid);
if (sid) {
char *ctx = NULL;
u32 len;
if (selinux_ctxid_to_string(sid, &ctx, &len))
audit_log_format(ab, " ssid=%u", sid);
else
audit_log_format(ab, " subj=%s", ctx);
kfree(ctx);
}
audit_log_format(ab, " %s rule key=", action);
if (rule->filterkey)
audit_log_untrustedstring(ab, rule->filterkey);
else
audit_log_format(ab, "(null)");
audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
audit_log_end(ab);
}
/**
* audit_receive_filter - apply all rules to the specified message type
* @type: audit message type
@@ -1304,24 +1360,7 @@ int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
err = audit_add_rule(entry,
&audit_filter_list[entry->rule.listnr]);
if (sid) {
char *ctx = NULL;
u32 len;
if (selinux_ctxid_to_string(sid, &ctx, &len)) {
/* Maybe call audit_panic? */
audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
"auid=%u ssid=%u add rule to list=%d res=%d",
loginuid, sid, entry->rule.listnr, !err);
} else
audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
"auid=%u subj=%s add rule to list=%d res=%d",
loginuid, ctx, entry->rule.listnr, !err);
kfree(ctx);
} else
audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
"auid=%u add rule to list=%d res=%d",
loginuid, entry->rule.listnr, !err);
audit_log_rule_change(loginuid, sid, "add", &entry->rule, !err);
if (err)
audit_free_rule(entry);
@@ -1337,24 +1376,8 @@ int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
err = audit_del_rule(entry,
&audit_filter_list[entry->rule.listnr]);
if (sid) {
char *ctx = NULL;
u32 len;
if (selinux_ctxid_to_string(sid, &ctx, &len)) {
/* Maybe call audit_panic? */
audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
"auid=%u ssid=%u remove rule from list=%d res=%d",
loginuid, sid, entry->rule.listnr, !err);
} else
audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
"auid=%u subj=%s remove rule from list=%d res=%d",
loginuid, ctx, entry->rule.listnr, !err);
kfree(ctx);
} else
audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
"auid=%u remove rule from list=%d res=%d",
loginuid, entry->rule.listnr, !err);
audit_log_rule_change(loginuid, sid, "remove", &entry->rule,
!err);
audit_free_rule(entry);
break;