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Message-ID: <49A1C200.80609@numericable.fr>
Date: Sun, 22 Feb 2009 22:22:08 +0100
From: etienne <etienne.basset@...ericable.fr>
To: Casey Schaufler <casey@...aufler-ca.com>,
Paul Moore <paul.moore@...com>
CC: LSM <linux-security-module@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
paulmck@...ux.vnet.ibm.com
Subject: [PATCH][SMACK][RFC] convert smack_netlbladdrs to standard list V2
hello,
please find below my seond try to convert smack_netlbladdrs to standard list
(patch on top of .29rc5 + [PATCH] SMACK netlabel fixes v2)
I tested it and found no regression, no hangs etc...
change since v1 : use rcu variants for list manipulation (thanks Tetsuo Handa a Paul McKenney)
Please let me know if there are problems
Etienne
Signed-off-by: <etienne.basset@...ericable.fr>
---
diff --git a/security/smack/smack.h b/security/smack/smack.h
index b79582e..2db35d7 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -18,6 +18,8 @@
#include <linux/security.h>
#include <linux/in.h>
#include <net/netlabel.h>
+#include <linux/list.h>
+#include <linux/rculist.h>
/*
* Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
@@ -69,6 +71,7 @@ struct smack_rule {
*/
struct smk_list_entry {
struct smk_list_entry *smk_next;
+ struct list_head list;
struct smack_rule smk_rule;
};
@@ -85,7 +88,7 @@ struct smack_cipso {
* An entry in the table identifying hosts.
*/
struct smk_netlbladdr {
- struct smk_netlbladdr *smk_next;
+ struct list_head list;
struct sockaddr_in smk_host; /* network address */
struct in_addr smk_mask; /* network mask */
char *smk_label; /* label */
@@ -113,6 +116,7 @@ struct smk_netlbladdr {
* the cipso direct mapping in used internally.
*/
struct smack_known {
+ struct list_head list;
struct smack_known *smk_next;
char smk_known[SMK_LABELLEN];
u32 smk_secid;
@@ -215,7 +219,9 @@ extern struct smack_known smack_known_star;
extern struct smack_known smack_known_web;
extern struct smk_list_entry *smack_list;
-extern struct smk_netlbladdr *smack_netlbladdrs;
+extern struct list_head smack_know_list;
+extern struct list_head smack_rule_list;
+extern struct list_head smk_netlbladdr_list;
extern struct security_operations smack_ops;
/*
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index e7ded13..65a4a8a 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1509,8 +1509,8 @@ static char *smack_host_label(struct sockaddr_in *sip)
if (siap->s_addr == 0)
return NULL;
-
- for (snp = smack_netlbladdrs; snp != NULL; snp = snp->smk_next) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(snp, &smk_netlbladdr_list, list) {
/*
* we break after finding the first match because
* the list is sorted from longest to shortest mask
@@ -1518,10 +1518,11 @@ static char *smack_host_label(struct sockaddr_in *sip)
*/
if ((&snp->smk_host.sin_addr)->s_addr ==
(siap->s_addr & (&snp->smk_mask)->s_addr)) {
+ rcu_read_unlock();
return snp->smk_label;
}
}
-
+ rcu_read_unlock();
return NULL;
}
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 51f0efc..7494808 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -80,7 +80,8 @@ char *smack_onlycap;
* Packets are sent there unlabeled, but only from tasks that
* can write to the specified label.
*/
-struct smk_netlbladdr *smack_netlbladdrs;
+
+LIST_HEAD(smk_netlbladdr_list);
static int smk_cipso_doi_value = SMACK_CIPSO_DOI_DEFAULT;
struct smk_list_entry *smack_list;
@@ -637,18 +638,21 @@ static void *netlbladdr_seq_start(struct seq_file *s, loff_t *pos)
{
if (*pos == SEQ_READ_FINISHED)
return NULL;
-
- return smack_netlbladdrs;
+ if (list_empty(&smk_netlbladdr_list))
+ return NULL;
+ return &smk_netlbladdr_list;
}
static void *netlbladdr_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
- struct smk_netlbladdr *skp = ((struct smk_netlbladdr *) v)->smk_next;
-
- if (skp == NULL)
+ struct list_head *list = v;
+
+ if (list_is_last(list->next, &smk_netlbladdr_list)) {
*pos = SEQ_READ_FINISHED;
+ return NULL;
+ }
- return skp;
+ return list->next;
}
#define BEBITS (sizeof(__be32) * 8)
@@ -657,7 +661,8 @@ static void *netlbladdr_seq_next(struct seq_file *s, void *v, loff_t *pos)
*/
static int netlbladdr_seq_show(struct seq_file *s, void *v)
{
- struct smk_netlbladdr *skp = (struct smk_netlbladdr *) v;
+ struct list_head *list = v;
+ struct smk_netlbladdr *skp = container_of(list->next, struct smk_netlbladdr, list);
unsigned char *hp = (char *) &skp->smk_host.sin_addr.s_addr;
int maskn;
u32 temp_mask = be32_to_cpu(skp->smk_mask.s_addr);
@@ -701,33 +706,37 @@ static int smk_open_netlbladdr(struct inode *inode, struct file *file)
*
* This helper insert netlabel in the smack_netlbladdrs list
* sorted by netmask length (longest to smallest)
+ * locked by &smk_netlbladdr_lock in smk_write_netlbladdr
+ *
*/
static void smk_netlbladdr_insert(struct smk_netlbladdr *new)
{
- struct smk_netlbladdr *m;
+ struct smk_netlbladdr *m, *m_next;
- if (smack_netlbladdrs == NULL) {
- smack_netlbladdrs = new;
- return;
- }
+ if (list_empty(&smk_netlbladdr_list)) {
+ list_add_rcu(&new->list, &smk_netlbladdr_list);
+ return;
+ }
/* the comparison '>' is a bit hacky, but works */
- if (new->smk_mask.s_addr > smack_netlbladdrs->smk_mask.s_addr) {
- new->smk_next = smack_netlbladdrs;
- smack_netlbladdrs = new;
- return;
- }
- for (m = smack_netlbladdrs; m != NULL; m = m->smk_next) {
- if (m->smk_next == NULL) {
- m->smk_next = new;
- return;
- }
- if (new->smk_mask.s_addr > m->smk_next->smk_mask.s_addr) {
- new->smk_next = m->smk_next;
- m->smk_next = new;
- return;
- }
- }
+ m = container_of(rcu_dereference(smk_netlbladdr_list.next), struct smk_netlbladdr, list);
+
+ if (new->smk_mask.s_addr > m->smk_mask.s_addr) {
+ list_add_rcu(&new->list, &smk_netlbladdr_list);
+ return;
+ }
+
+ list_for_each_entry_rcu(m, &smk_netlbladdr_list, list) {
+ if (list_is_last(&m->list, &smk_netlbladdr_list)) {
+ list_add_rcu(&new->list, &m->list);
+ return;
+ }
+ m_next = container_of(rcu_dereference(m->list.next), struct smk_netlbladdr, list);
+ if (new->smk_mask.s_addr > m_next->smk_mask.s_addr) {
+ list_add_rcu(&new->list, &m->list);
+ return;
+ }
+ }
}
@@ -754,6 +763,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
struct netlbl_audit audit_info;
struct in_addr mask;
unsigned int m;
+ int found;
u32 mask_bits = (1<<31);
__be32 nsa;
u32 temp_mask;
@@ -807,14 +817,18 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
nsa = newname.sin_addr.s_addr;
/* try to find if the prefix is already in the list */
- for (skp = smack_netlbladdrs; skp != NULL; skp = skp->smk_next)
+ found = 0;
+ list_for_each_entry_rcu(skp, &smk_netlbladdr_list, list) {
if (skp->smk_host.sin_addr.s_addr == nsa &&
- skp->smk_mask.s_addr == mask.s_addr)
- break;
+ skp->smk_mask.s_addr == mask.s_addr) {
+ found = 1;
+ break;
+ }
+ }
smk_netlabel_audit_set(&audit_info);
- if (skp == NULL) {
+ if (!found) {
skp = kzalloc(sizeof(*skp), GFP_KERNEL);
if (skp == NULL)
rc = -ENOMEM;
--
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