X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=security%2Fdevice_cgroup.c;h=46f23971f7e4208d9487cbb9cf477790a8fb378a;hb=44ea91c597ae4641d9ac21b8bbba0795d2f4261e;hp=236fffa9d05e5ed7e904489f5051430b87fe664e;hpb=f92523e3a7861f5dbd76021e0719a35fe8771f2d;p=linux-2.6-omap-h63xx.git

diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 236fffa9d05..46f23971f7e 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -41,6 +41,7 @@ struct dev_whitelist_item {
 	short type;
 	short access;
 	struct list_head list;
+	struct rcu_head rcu;
 };
 
 struct dev_cgroup {
@@ -133,11 +134,19 @@ static int dev_whitelist_add(struct dev_cgroup *dev_cgroup,
 	}
 
 	if (whcopy != NULL)
-		list_add_tail(&whcopy->list, &dev_cgroup->whitelist);
+		list_add_tail_rcu(&whcopy->list, &dev_cgroup->whitelist);
 	spin_unlock(&dev_cgroup->lock);
 	return 0;
 }
 
+static void whitelist_item_free(struct rcu_head *rcu)
+{
+	struct dev_whitelist_item *item;
+
+	item = container_of(rcu, struct dev_whitelist_item, rcu);
+	kfree(item);
+}
+
 /*
  * called under cgroup_lock()
  * since the list is visible to other tasks, we need the spinlock also
@@ -161,8 +170,8 @@ static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup,
 remove:
 		walk->access &= ~wh->access;
 		if (!walk->access) {
-			list_del(&walk->list);
-			kfree(walk);
+			list_del_rcu(&walk->list);
+			call_rcu(&walk->rcu, whitelist_item_free);
 		}
 	}
 	spin_unlock(&dev_cgroup->lock);
@@ -193,7 +202,7 @@ static struct cgroup_subsys_state *devcgroup_create(struct cgroup_subsys *ss,
 		}
 		wh->minor = wh->major = ~0;
 		wh->type = DEV_ALL;
-		wh->access = ACC_MKNOD | ACC_READ | ACC_WRITE;
+		wh->access = ACC_MASK;
 		list_add(&wh->list, &dev_cgroup->whitelist);
 	} else {
 		parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup);
@@ -255,11 +264,10 @@ static char type_to_char(short type)
 
 static void set_majmin(char *str, unsigned m)
 {
-	memset(str, 0, MAJMINLEN);
 	if (m == ~0)
-		sprintf(str, "*");
+		strcpy(str, "*");
 	else
-		snprintf(str, MAJMINLEN, "%u", m);
+		sprintf(str, "%u", m);
 }
 
 static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft,
@@ -269,15 +277,15 @@ static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft,
 	struct dev_whitelist_item *wh;
 	char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN];
 
-	spin_lock(&devcgroup->lock);
-	list_for_each_entry(wh, &devcgroup->whitelist, list) {
+	rcu_read_lock();
+	list_for_each_entry_rcu(wh, &devcgroup->whitelist, list) {
 		set_access(acc, wh->access);
 		set_majmin(maj, wh->major);
 		set_majmin(min, wh->minor);
 		seq_printf(m, "%c %s:%s %s\n", type_to_char(wh->type),
 			   maj, min, acc);
 	}
-	spin_unlock(&devcgroup->lock);
+	rcu_read_unlock();
 
 	return 0;
 }
@@ -351,6 +359,7 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
 {
 	struct dev_cgroup *cur_devcgroup;
 	const char *b;
+	char *endp;
 	int retval = 0, count;
 	struct dev_whitelist_item wh;
 
@@ -386,11 +395,8 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
 		wh.major = ~0;
 		b++;
 	} else if (isdigit(*b)) {
-		wh.major = 0;
-		while (isdigit(*b)) {
-			wh.major = wh.major*10+(*b-'0');
-			b++;
-		}
+		wh.major = simple_strtoul(b, &endp, 10);
+		b = endp;
 	} else {
 		return -EINVAL;
 	}
@@ -403,11 +409,8 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
 		wh.minor = ~0;
 		b++;
 	} else if (isdigit(*b)) {
-		wh.minor = 0;
-		while (isdigit(*b)) {
-			wh.minor = wh.minor*10+(*b-'0');
-			b++;
-		}
+		wh.minor = simple_strtoul(b, &endp, 10);
+		b = endp;
 	} else {
 		return -EINVAL;
 	}
@@ -505,13 +508,12 @@ int devcgroup_inode_permission(struct inode *inode, int mask)
 		return 0;
 	if (!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode))
 		return 0;
-	dev_cgroup = css_to_devcgroup(task_subsys_state(current,
-				devices_subsys_id));
-	if (!dev_cgroup)
-		return 0;
 
-	spin_lock(&dev_cgroup->lock);
-	list_for_each_entry(wh, &dev_cgroup->whitelist, list) {
+	rcu_read_lock();
+
+	dev_cgroup = task_devcgroup(current);
+
+	list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
 		if (wh->type & DEV_ALL)
 			goto acc_check;
 		if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode))
@@ -527,10 +529,11 @@ acc_check:
 			continue;
 		if ((mask & MAY_READ) && !(wh->access & ACC_READ))
 			continue;
-		spin_unlock(&dev_cgroup->lock);
+		rcu_read_unlock();
 		return 0;
 	}
-	spin_unlock(&dev_cgroup->lock);
+
+	rcu_read_unlock();
 
 	return -EPERM;
 }
@@ -540,12 +543,10 @@ int devcgroup_inode_mknod(int mode, dev_t dev)
 	struct dev_cgroup *dev_cgroup;
 	struct dev_whitelist_item *wh;
 
-	dev_cgroup = css_to_devcgroup(task_subsys_state(current,
-				devices_subsys_id));
-	if (!dev_cgroup)
-		return 0;
+	rcu_read_lock();
+
+	dev_cgroup = task_devcgroup(current);
 
-	spin_lock(&dev_cgroup->lock);
 	list_for_each_entry(wh, &dev_cgroup->whitelist, list) {
 		if (wh->type & DEV_ALL)
 			goto acc_check;
@@ -560,9 +561,11 @@ int devcgroup_inode_mknod(int mode, dev_t dev)
 acc_check:
 		if (!(wh->access & ACC_MKNOD))
 			continue;
-		spin_unlock(&dev_cgroup->lock);
+		rcu_read_unlock();
 		return 0;
 	}
-	spin_unlock(&dev_cgroup->lock);
+
+	rcu_read_unlock();
+
 	return -EPERM;
 }