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netlabel: Replace protocol/NetLabel linking with refrerence counts

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NetLabel has always had a list of backpointers in the CIPSO DOI definition
structure which pointed to the NetLabel LSM domain mapping structures which
referenced the CIPSO DOI struct.  The rationale for this was that when an
administrator removed a CIPSO DOI from the system all of the associated
NetLabel LSM domain mappings should be removed as well; a list of
backpointers made this a simple operation.

Unfortunately, while the backpointers did make the removal easier they were
a bit of a mess from an implementation point of view which was making
further development difficult.  Since the removal of a CIPSO DOI is a
realtively rare event it seems to make sense to remove this backpointer
list as the optimization was hurting us more then it was helping.  However,
we still need to be able to track when a CIPSO DOI definition is being used
so replace the backpointer list with a reference count.  In order to
preserve the current functionality of removing the associated LSM domain
mappings when a CIPSO DOI is removed we walk the LSM domain mapping table,
removing the relevant entries.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Reviewed-by: James Morris <jmorris@namei.org>
This commit is contained in:
Paul Moore
2008-10-10 10:16:31 -04:00
parent a8134296ba
commit b1edeb1023
8 changed files with 253 additions and 284 deletions
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113
net/netlabel/netlabel_domainhash.c
View File

@@ -217,20 +217,6 @@ int netlbl_domhsh_add(struct netlbl_dom_map *entry,
u32 bkt;
struct audit_buffer *audit_buf;
switch (entry->type) {
case NETLBL_NLTYPE_UNLABELED:
ret_val = 0;
break;
case NETLBL_NLTYPE_CIPSOV4:
ret_val = cipso_v4_doi_domhsh_add(entry->type_def.cipsov4,
entry->domain);
break;
default:
return -EINVAL;
}
if (ret_val != 0)
return ret_val;
entry->valid = 1;
INIT_RCU_HEAD(&entry->rcu);
@@ -271,16 +257,6 @@ int netlbl_domhsh_add(struct netlbl_dom_map *entry,
}
rcu_read_unlock();
if (ret_val != 0) {
switch (entry->type) {
case NETLBL_NLTYPE_CIPSOV4:
if (cipso_v4_doi_domhsh_remove(entry->type_def.cipsov4,
entry->domain) != 0)
BUG();
break;
}
}
return ret_val;
}
@@ -301,6 +277,59 @@ int netlbl_domhsh_add_default(struct netlbl_dom_map *entry,
return netlbl_domhsh_add(entry, audit_info);
}
/**
* netlbl_domhsh_remove_entry - Removes a given entry from the domain table
* @entry: the entry to remove
* @audit_info: NetLabel audit information
*
* Description:
* Removes an entry from the domain hash table and handles any updates to the
* lower level protocol handler (i.e. CIPSO). Caller is responsible for
* ensuring that the RCU read lock is held. Returns zero on success, negative
* on failure.
*
*/
int netlbl_domhsh_remove_entry(struct netlbl_dom_map *entry,
struct netlbl_audit *audit_info)
{
int ret_val = 0;
struct audit_buffer *audit_buf;
if (entry == NULL)
return -ENOENT;
spin_lock(&netlbl_domhsh_lock);
if (entry->valid) {
entry->valid = 0;
if (entry != rcu_dereference(netlbl_domhsh_def))
list_del_rcu(&entry->list);
else
rcu_assign_pointer(netlbl_domhsh_def, NULL);
} else
ret_val = -ENOENT;
spin_unlock(&netlbl_domhsh_lock);
audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info);
if (audit_buf != NULL) {
audit_log_format(audit_buf,
" nlbl_domain=%s res=%u",
entry->domain ? entry->domain : "(default)",
ret_val == 0 ? 1 : 0);
audit_log_end(audit_buf);
}
if (ret_val == 0) {
switch (entry->type) {
case NETLBL_NLTYPE_CIPSOV4:
cipso_v4_doi_putdef(entry->type_def.cipsov4);
break;
}
call_rcu(&entry->rcu, netlbl_domhsh_free_entry);
}
return ret_val;
}
/**
* netlbl_domhsh_remove - Removes an entry from the domain hash table
* @domain: the domain to remove
@@ -314,47 +343,17 @@ int netlbl_domhsh_add_default(struct netlbl_dom_map *entry,
*/
int netlbl_domhsh_remove(const char *domain, struct netlbl_audit *audit_info)
{
int ret_val = -ENOENT;
int ret_val;
struct netlbl_dom_map *entry;
struct audit_buffer *audit_buf;
rcu_read_lock();
if (domain)
entry = netlbl_domhsh_search(domain);
else
entry = netlbl_domhsh_search_def(domain);
if (entry == NULL)
goto remove_return;
switch (entry->type) {
case NETLBL_NLTYPE_CIPSOV4:
cipso_v4_doi_domhsh_remove(entry->type_def.cipsov4,
entry->domain);
break;
}
spin_lock(&netlbl_domhsh_lock);
if (entry->valid) {
entry->valid = 0;
if (entry != rcu_dereference(netlbl_domhsh_def))
list_del_rcu(&entry->list);
else
rcu_assign_pointer(netlbl_domhsh_def, NULL);
ret_val = 0;
}
spin_unlock(&netlbl_domhsh_lock);
audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info);
if (audit_buf != NULL) {
audit_log_format(audit_buf,
" nlbl_domain=%s res=%u",
entry->domain ? entry->domain : "(default)",
ret_val == 0 ? 1 : 0);
audit_log_end(audit_buf);
}
remove_return:
ret_val = netlbl_domhsh_remove_entry(entry, audit_info);
rcu_read_unlock();
if (ret_val == 0)
call_rcu(&entry->rcu, netlbl_domhsh_free_entry);
return ret_val;
}