TOMOYO: Add garbage collector.

This patch adds garbage collector support to TOMOYO.
Elements are protected by "struct srcu_struct tomoyo_ss".

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 40 insertions, 46 deletions

diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c
index 9557168b3767..c00df45c7ede 100644
--- a/security/tomoyo/realpath.c
+++ b/security/tomoyo/realpath.c
@@ -205,9 +205,9 @@ char *tomoyo_realpath_nofollow(const char *pathname)
 }
 
 /* Memory allocated for non-string data. */
-static unsigned int tomoyo_allocated_memory_for_elements;
-/* Quota for holding non-string data. */
-static unsigned int tomoyo_quota_for_elements;
+static atomic_t tomoyo_policy_memory_size;
+/* Quota for holding policy. */
+static unsigned int tomoyo_quota_for_policy;
 
 /**
  * tomoyo_memory_ok - Check memory quota.
@@ -222,26 +222,30 @@ static unsigned int tomoyo_quota_for_elements;
 bool tomoyo_memory_ok(void *ptr)
 {
         int allocated_len = ptr ? ksize(ptr) : 0;
-        bool result = false;
-        if (!ptr || (tomoyo_quota_for_elements &&
-                     tomoyo_allocated_memory_for_elements
-                     + allocated_len > tomoyo_quota_for_elements)) {
-                printk(KERN_WARNING "ERROR: Out of memory "
-                       "for tomoyo_alloc_element().\n");
-                if (!tomoyo_policy_loaded)
-                        panic("MAC Initialization failed.\n");
-        } else {
-                result = true;
-                tomoyo_allocated_memory_for_elements += allocated_len;
+        atomic_add(allocated_len, &tomoyo_policy_memory_size);
+        if (ptr && (!tomoyo_quota_for_policy ||
+                    atomic_read(&tomoyo_policy_memory_size)
+                    <= tomoyo_quota_for_policy)) {
                 memset(ptr, 0, allocated_len);
+                return true;
         }
-        return result;
+        printk(KERN_WARNING "ERROR: Out of memory "
+               "for tomoyo_alloc_element().\n");
+        if (!tomoyo_policy_loaded)
+                panic("MAC Initialization failed.\n");
+        return false;
 }
 
-/* Memory allocated for string data in bytes. */
-static unsigned int tomoyo_allocated_memory_for_savename;
-/* Quota for holding string data in bytes. */
-static unsigned int tomoyo_quota_for_savename;
+/**
+ * tomoyo_memory_free - Free memory for elements.
+ *
+ * @ptr:  Pointer to allocated memory.
+ */
+void tomoyo_memory_free(void *ptr)
+{
+        atomic_sub(ksize(ptr), &tomoyo_policy_memory_size);
+        kfree(ptr);
+}
 
 /*
  * tomoyo_name_list is used for holding string data used by TOMOYO.
@@ -249,7 +253,9 @@ static unsigned int tomoyo_quota_for_savename;
  * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
  * "const struct tomoyo_path_info *".
  */
-static struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
+struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
+/* Lock for protecting tomoyo_name_list . */
+DEFINE_MUTEX(tomoyo_name_list_lock);
 
 /**
  * tomoyo_get_name - Allocate permanent memory for string data.
@@ -260,7 +266,6 @@ static struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
  */
 const struct tomoyo_path_info *tomoyo_get_name(const char *name)
 {
-        static DEFINE_MUTEX(lock);
         struct tomoyo_name_entry *ptr;
         unsigned int hash;
         int len;
@@ -272,7 +277,7 @@ const struct tomoyo_path_info *tomoyo_get_name(const char *name)
         len = strlen(name) + 1;
         hash = full_name_hash((const unsigned char *) name, len - 1);
         head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
-        mutex_lock(&lock);
+        mutex_lock(&tomoyo_name_list_lock);
         list_for_each_entry(ptr, head, list) {
                 if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name))
                         continue;
@@ -281,9 +286,9 @@ const struct tomoyo_path_info *tomoyo_get_name(const char *name)
         }
         ptr = kzalloc(sizeof(*ptr) + len, GFP_KERNEL);
         allocated_len = ptr ? ksize(ptr) : 0;
-        if (!ptr || (tomoyo_quota_for_savename &&
-                     tomoyo_allocated_memory_for_savename + allocated_len
-                     > tomoyo_quota_for_savename)) {
+        if (!ptr || (tomoyo_quota_for_policy &&
+                     atomic_read(&tomoyo_policy_memory_size) + allocated_len
+                     > tomoyo_quota_for_policy)) {
                 kfree(ptr);
                 printk(KERN_WARNING "ERROR: Out of memory "
                        "for tomoyo_get_name().\n");
@@ -292,14 +297,14 @@ const struct tomoyo_path_info *tomoyo_get_name(const char *name)
                 ptr = NULL;
                 goto out;
         }
-        tomoyo_allocated_memory_for_savename += allocated_len;
+        atomic_add(allocated_len, &tomoyo_policy_memory_size);
         ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
         memmove((char *) ptr->entry.name, name, len);
         atomic_set(&ptr->users, 1);
         tomoyo_fill_path_info(&ptr->entry);
         list_add_tail(&ptr->list, head);
  out:
-        mutex_unlock(&lock);
+        mutex_unlock(&tomoyo_name_list_lock);
         return ptr ? &ptr->entry : NULL;
 }
 
@@ -334,28 +339,19 @@ void __init tomoyo_realpath_init(void)
 int tomoyo_read_memory_counter(struct tomoyo_io_buffer *head)
 {
         if (!head->read_eof) {
-                const unsigned int shared
-                        = tomoyo_allocated_memory_for_savename;
-                const unsigned int private
-                        = tomoyo_allocated_memory_for_elements;
+                const unsigned int policy
+                        = atomic_read(&tomoyo_policy_memory_size);
                 char buffer[64];
 
                 memset(buffer, 0, sizeof(buffer));
-                if (tomoyo_quota_for_savename)
-                        snprintf(buffer, sizeof(buffer) - 1,
-                                 "   (Quota: %10u)",
-                                 tomoyo_quota_for_savename);
-                else
-                        buffer[0] = '\0';
-                tomoyo_io_printf(head, "Shared:  %10u%s\n", shared, buffer);
-                if (tomoyo_quota_for_elements)
+                if (tomoyo_quota_for_policy)
                         snprintf(buffer, sizeof(buffer) - 1,
                                  "   (Quota: %10u)",
-                                 tomoyo_quota_for_elements);
+                                 tomoyo_quota_for_policy);
                 else
                         buffer[0] = '\0';
-                tomoyo_io_printf(head, "Private: %10u%s\n", private, buffer);
-                tomoyo_io_printf(head, "Total:   %10u\n", shared + private);
+                tomoyo_io_printf(head, "Policy:  %10u%s\n", policy, buffer);
+                tomoyo_io_printf(head, "Total:   %10u\n", policy);
                 head->read_eof = true;
         }
         return 0;
@@ -373,9 +369,7 @@ int tomoyo_write_memory_quota(struct tomoyo_io_buffer *head)
         char *data = head->write_buf;
         unsigned int size;
 
-        if (sscanf(data, "Shared: %u", &size) == 1)
-                tomoyo_quota_for_savename = size;
-        else if (sscanf(data, "Private: %u", &size) == 1)
-                tomoyo_quota_for_elements = size;
+        if (sscanf(data, "Policy: %u", &size) == 1)
+                tomoyo_quota_for_policy = size;
         return 0;
 }