Re: [PATCH][SMACK] convert smack_known list to a standard linux list.

etienne
2009-02-23T06:31:51Z

Casey Schaufler wrote:
> etienne wrote:
>> hello,
>>
>> this patch on top of [PATCH][SMACK] convert smack rule list to linux list V2
>> converts "smack_known" to a regular linux list. (rcu variant)
>>
>>
>
> I'm having some trouble applying this group of patches.
> I assume that I'm starting at the wrong place. Could you
> do a single patch to help me avoid confusion?
>
> Thank you.
>
>> regards,
>> Etienne
>>
>> Signed-off-by: <etienne.basset@numericable.fr>
>> ---
>> diff --git a/security/smack/smack.h b/security/smack/smack.h
>> index 0dcb907..64164f8 100644
>> --- a/security/smack/smack.h
>> +++ b/security/smack/smack.h
>> @@ -109,7 +109,6 @@ struct smk_netlbladdr {
>> */
>>
>
>
>

here you are!
(it is still on top of my 02/20 "[PATCH] SMACK netlabel fixes v2")

happy testing ;)
Etienne

Signed-off-by: <etienne.basset@numericable.fr>
---
diff --git a/security/smack/smack.h b/security/smack/smack.h
index b79582e..64164f8 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
@@ -59,17 +61,10 @@ struct inode_smack {
* A label access rule.
*/
struct smack_rule {
- char *smk_subject;
- char *smk_object;
- int smk_access;
-};
-
-/*
- * An entry in the table of permitted label accesses.
- */
-struct smk_list_entry {
- struct smk_list_entry *smk_next;
- struct smack_rule smk_rule;
+ struct list_head list;
+ char *smk_subject;
+ char *smk_object;
+ int smk_access;
};

/*
@@ -85,7 +80,7 @@ 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 */
@@ -113,7 +108,7 @@ struct smk_netlbladdr {
* the cipso direct mapping in used internally.
*/
struct smack_known {
- struct smack_known *smk_next;
+ struct list_head list;
char smk_known[SMK_LABELLEN];
u32 smk_secid;
struct smack_cipso *smk_cipso;
@@ -206,7 +201,6 @@ extern int smack_cipso_direct;
extern char *smack_net_ambient;
extern char *smack_onlycap;

-extern struct smack_known *smack_known;
extern struct smack_known smack_known_floor;
extern struct smack_known smack_known_hat;
extern struct smack_known smack_known_huh;
@@ -214,8 +208,10 @@ extern struct smack_known smack_known_invalid;
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_known_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_access.c b/security/smack/smack_access.c
index 2e0b83e..b16086f 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -16,48 +16,42 @@
#include "smack.h"

struct smack_known smack_known_huh = {
- .smk_next = NULL,
.smk_known = "?",
.smk_secid = 2,
.smk_cipso = NULL,
};

struct smack_known smack_known_hat = {
- .smk_next = &smack_known_huh,
.smk_known = "^",
.smk_secid = 3,
.smk_cipso = NULL,
};

struct smack_known smack_known_star = {
- .smk_next = &smack_known_hat,
.smk_known = "*",
.smk_secid = 4,
.smk_cipso = NULL,
};

struct smack_known smack_known_floor = {
- .smk_next = &smack_known_star,
.smk_known = "_",
.smk_secid = 5,
.smk_cipso = NULL,
};

struct smack_known smack_known_invalid = {
- .smk_next = &smack_known_floor,
.smk_known = "",
.smk_secid = 6,
.smk_cipso = NULL,
};

struct smack_known smack_known_web = {
- .smk_next = &smack_known_invalid,
.smk_known = "@",
.smk_secid = 7,
.smk_cipso = NULL,
};

-struct smack_known *smack_known = &smack_known_web;
+LIST_HEAD(smack_known_list);

/*
* The initial value needs to be bigger than any of the
@@ -87,7 +81,6 @@ static u32 smack_next_secid = 10;
int smk_access(char *subject_label, char *object_label, int request)
{
u32 may = MAY_NOT;
- struct smk_list_entry *sp;
struct smack_rule *srp;

/*
@@ -139,9 +132,8 @@ int smk_access(char *subject_label, char *object_label, int request)
* access (e.g. read is included in readwrite) it's
* good.
*/
- for (sp = smack_list; sp != NULL; sp = sp->smk_next) {
- srp = &sp->smk_rule;
-
+ rcu_read_lock();
+ list_for_each_entry_rcu(srp, &smack_rule_list, list) {
if (srp->smk_subject == subject_label ||
strcmp(srp->smk_subject, subject_label) == 0) {
if (srp->smk_object == object_label ||
@@ -151,6 +143,7 @@ int smk_access(char *subject_label, char *object_label, int request)
}
}
}
+ rcu_read_unlock();
/*
* This is a bit map operation.
*/
@@ -228,14 +221,17 @@ struct smack_known *smk_import_entry(const char *string, int len)

mutex_lock(&smack_known_lock);

- for (skp = smack_known; skp != NULL; skp = skp->smk_next)
- if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0)
+ found = 0;
+ list_for_each_entry_rcu(skp, &smack_known_list, list) {
+ if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0) {
+ found = 1;
break;
+ }
+ }

- if (skp == NULL) {
+ if (found == 0) {
skp = kzalloc(sizeof(struct smack_known), GFP_KERNEL);
if (skp != NULL) {
- skp->smk_next = smack_known;
strncpy(skp->smk_known, smack, SMK_MAXLEN);
skp->smk_secid = smack_next_secid++;
skp->smk_cipso = NULL;
@@ -245,7 +241,7 @@ struct smack_known *smk_import_entry(const char *string, int len)
* filled before putting it on the list.
*/
smp_mb();
- smack_known = skp;
+ list_add(&skp->list, &smack_known_list);
}
}

@@ -283,14 +279,19 @@ char *smack_from_secid(const u32 secid)
{
struct smack_known *skp;

- for (skp = smack_known; skp != NULL; skp = skp->smk_next)
- if (skp->smk_secid == secid)
+ rcu_read_lock();
+ list_for_each_entry_rcu(skp, &smack_known_list, list) {
+ if (skp->smk_secid == secid) {
+ rcu_read_unlock();
return skp->smk_known;
+ }
+ }

/*
* If we got this far someone asked for the translation
* of a secid that is not on the list.
*/
+ rcu_read_unlock();
return smack_known_invalid.smk_known;
}

@@ -305,9 +306,14 @@ u32 smack_to_secid(const char *smack)
{
struct smack_known *skp;

- for (skp = smack_known; skp != NULL; skp = skp->smk_next)
- if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0)
+ rcu_read_lock();
+ list_for_each_entry_rcu(skp, &smack_known_list, list) {
+ if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0) {
+ rcu_read_unlock();
return skp->smk_secid;
+ }
+ }
+ rcu_read_unlock();
return 0;
}

@@ -332,7 +338,8 @@ void smack_from_cipso(u32 level, char *cp, char *result)
struct smack_known *kp;
char *final = NULL;

- for (kp = smack_known; final == NULL && kp != NULL; kp = kp->smk_next) {
+ rcu_read_lock();
+ list_for_each_entry(kp, &smack_known_list, list) {
if (kp->smk_cipso == NULL)
continue;

@@ -344,6 +351,7 @@ void smack_from_cipso(u32 level, char *cp, char *result)

spin_unlock_bh(&kp->smk_cipsolock);
}
+ rcu_read_unlock();
if (final == NULL)
final = smack_known_huh.smk_known;
strncpy(result, final, SMK_MAXLEN);
@@ -360,13 +368,19 @@ void smack_from_cipso(u32 level, char *cp, char *result)
int smack_to_cipso(const char *smack, struct smack_cipso *cp)
{
struct smack_known *kp;
+ int found = 0;

- for (kp = smack_known; kp != NULL; kp = kp->smk_next)
+ rcu_read_lock();
+ list_for_each_entry_rcu(kp, &smack_known_list, list) {
if (kp->smk_known == smack ||
- strcmp(kp->smk_known, smack) == 0)
+ strcmp(kp->smk_known, smack) == 0) {
+ found = 1;
break;
+ }
+ }
+ rcu_read_unlock();

- if (kp == NULL || kp->smk_cipso == NULL)
+ if (found == 0 || kp->smk_cipso == NULL)
return -ENOENT;

memcpy(cp, kp->smk_cipso, sizeof(struct smack_cipso));
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index e7ded13..e6f89d6 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;
}

@@ -2934,6 +2935,17 @@ struct security_operations smack_ops = {
.release_secctx = smack_release_secctx,
};

+
+static __init init_smack_know_list(void)
+{
+ list_add(&smack_known_huh.list, &smack_known_list);
+ list_add(&smack_known_hat.list, &smack_known_list);
+ list_add(&smack_known_star.list, &smack_known_list);
+ list_add(&smack_known_floor.list, &smack_known_list);
+ list_add(&smack_known_invalid.list, &smack_known_list);
+ list_add(&smack_known_web.list, &smack_known_list);
+}
+
/**
* smack_init - initialize the smack system
*
@@ -2954,6 +2966,8 @@ static __init int smack_init(void)
cred = (struct cred *) current->cred;
cred->security = &smack_known_floor.smk_known;

+ /* initilize the smack_know_list */
+ init_smack_know_list();
/*
* Initialize locks
*/
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 51f0efc..665e2cc 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -80,10 +80,11 @@ 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);
+LIST_HEAD(smack_rule_list);

static int smk_cipso_doi_value = SMACK_CIPSO_DOI_DEFAULT;
-struct smk_list_entry *smack_list;

#define SEQ_READ_FINISHED 1

@@ -134,24 +135,27 @@ static void *load_seq_start(struct seq_file *s, loff_t *pos)
{
if (*pos == SEQ_READ_FINISHED)
return NULL;
-
- return smack_list;
+ if (list_empty(&smack_rule_list))
+ return NULL;
+ return &smack_rule_list;
}

static void *load_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
- struct smk_list_entry *skp = ((struct smk_list_entry *) v)->smk_next;
+ struct list_head *list = v;

- if (skp == NULL)
+ if (list_is_last(list->next, &smack_rule_list)) {
*pos = SEQ_READ_FINISHED;
-
- return skp;
+ return NULL;
+ }
+ return list->next;
}

static int load_seq_show(struct seq_file *s, void *v)
{
- struct smk_list_entry *slp = (struct smk_list_entry *) v;
- struct smack_rule *srp = &slp->smk_rule;
+ struct list_head *list = v;
+ struct smack_rule *srp =
+ container_of(list->next, struct smack_rule, list);

seq_printf(s, "%s %s", (char *)srp->smk_subject,
(char *)srp->smk_object);
@@ -212,32 +216,23 @@ static int smk_open_load(struct inode *inode, struct file *file)
*/
static int smk_set_access(struct smack_rule *srp)
{
- struct smk_list_entry *sp;
- struct smk_list_entry *newp;
+ struct smack_rule *sp;
int ret = 0;
-
+ int found;
mutex_lock(&smack_list_lock);

- for (sp = smack_list; sp != NULL; sp = sp->smk_next)
- if (sp->smk_rule.smk_subject == srp->smk_subject &&
- sp->smk_rule.smk_object == srp->smk_object) {
- sp->smk_rule.smk_access = srp->smk_access;
+ found = 0;
+ list_for_each_entry_rcu(sp, &smack_rule_list, list) {
+ if (sp->smk_subject == srp->smk_subject &&
+ sp->smk_object == srp->smk_object) {
+ found = 1;
+ sp->smk_access = srp->smk_access;
break;
}
-
- if (sp == NULL) {
- newp = kzalloc(sizeof(struct smk_list_entry), GFP_KERNEL);
- if (newp == NULL) {
- ret = -ENOMEM;
- goto out;
- }
-
- newp->smk_rule = *srp;
- newp->smk_next = smack_list;
- smack_list = newp;
}
+ if (found == 0)
+ list_add_rcu(&srp->list, &smack_rule_list);

-out:
mutex_unlock(&smack_list_lock);

return ret;
@@ -261,7 +256,7 @@ out:
static ssize_t smk_write_load(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
- struct smack_rule rule;
+ struct smack_rule *rule;
char *data;
int rc = -EINVAL;

@@ -272,9 +267,8 @@ static ssize_t smk_write_load(struct file *file, const char __user *buf,
*/
if (!capable(CAP_MAC_ADMIN))
return -EPERM;
- if (*ppos != 0)
- return -EINVAL;
- if (count != SMK_LOADLEN)
+
+ if (*ppos != 0 || count != SMK_LOADLEN)
return -EINVAL;

data = kzalloc(count, GFP_KERNEL);
@@ -286,25 +280,31 @@ static ssize_t smk_write_load(struct file *file, const char __user *buf,
goto out;
}

- rule.smk_subject = smk_import(data, 0);
- if (rule.smk_subject == NULL)
+ rule = kzalloc(sizeof(*rule), GFP_KERNEL);
+ if (rule == NULL) {
+ rc = -ENOMEM;
goto out;
+ }

- rule.smk_object = smk_import(data + SMK_LABELLEN, 0);
- if (rule.smk_object == NULL)
- goto out;
+ rule->smk_subject = smk_import(data, 0);
+ if (rule->smk_subject == NULL)
+ goto out_free;

- rule.smk_access = 0;
+ rule->smk_object = smk_import(data + SMK_LABELLEN, 0);
+ if (rule->smk_object == NULL)
+ goto out_free;
+
+ rule->smk_access = 0;

switch (data[SMK_LABELLEN + SMK_LABELLEN]) {
case '-':
break;
case 'r':
case 'R':
- rule.smk_access |= MAY_READ;
+ rule->smk_access |= MAY_READ;
break;
default:
- goto out;
+ goto out_free;
}

switch (data[SMK_LABELLEN + SMK_LABELLEN + 1]) {
@@ -312,10 +312,10 @@ static ssize_t smk_write_load(struct file *file, const char __user *buf,
break;
case 'w':
case 'W':
- rule.smk_access |= MAY_WRITE;
+ rule->smk_access |= MAY_WRITE;
break;
default:
- goto out;
+ goto out_free;
}

switch (data[SMK_LABELLEN + SMK_LABELLEN + 2]) {
@@ -323,10 +323,10 @@ static ssize_t smk_write_load(struct file *file, const char __user *buf,
break;
case 'x':
case 'X':
- rule.smk_access |= MAY_EXEC;
+ rule->smk_access |= MAY_EXEC;
break;
default:
- goto out;
+ goto out_free;
}

switch (data[SMK_LABELLEN + SMK_LABELLEN + 3]) {
@@ -334,17 +334,20 @@ static ssize_t smk_write_load(struct file *file, const char __user *buf,
break;
case 'a':
case 'A':
- rule.smk_access |= MAY_APPEND;
+ rule->smk_access |= MAY_APPEND;
break;
default:
- goto out;
+ goto out_free;
}

- rc = smk_set_access(&rule);
+ rc = smk_set_access(rule);

if (!rc)
rc = count;
+ goto out;

+out_free:
+ kfree(rule);
out:
kfree(data);
return rc;
@@ -432,24 +435,26 @@ static void *cipso_seq_start(struct seq_file *s, loff_t *pos)
{
if (*pos == SEQ_READ_FINISHED)
return NULL;
+ if (list_empty(&smack_known_list))
+ return NULL;

- return smack_known;
+ return &smack_known_list;
}

static void *cipso_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
- struct smack_known *skp = ((struct smack_known *) v)->smk_next;
+ struct list_head *list = v;

/*
- * Omit labels with no associated cipso value
+ * labels with no associated cipso value wont be printed
+ * in cipso_seq_show
*/
- while (skp != NULL && !skp->smk_cipso)
- skp = skp->smk_next;
-
- if (skp == NULL)
+ if (list_is_last(list->next, &smack_known_list)) {
*pos = SEQ_READ_FINISHED;
+ return NULL;
+ }

- return skp;
+ return list->next;
}

/*
@@ -458,7 +463,8 @@ static void *cipso_seq_next(struct seq_file *s, void *v, loff_t *pos)
*/
static int cipso_seq_show(struct seq_file *s, void *v)
{
- struct smack_known *skp = (struct smack_known *) v;
+ struct list_head *list = v;
+ struct smack_known *skp = container_of(list->next, struct smack_known, list);
struct smack_cipso *scp = skp->smk_cipso;
char *cbp;
char sep = '/';
@@ -637,18 +643,21 @@ 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 +666,8 @@ 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 +711,37 @@ 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 +768,7 @@ 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 +822,18 @@ 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;