TOMOYO: Remove memory pool for list elements.

Currently, TOMOYO allocates memory for list elements from memory pool allocated
by kmalloc(PAGE_SIZE). But that makes it difficult to kfree() when garbage
collector is added. Thus, remove memory pool and use kmalloc(sizeof()).

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

6 files changed, 73 insertions, 134 deletions

diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index 642e0e565dfc..e331e699cf54 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -900,9 +900,11 @@ static struct tomoyo_profile *tomoyo_find_or_assign_new_profile(const unsigned
         ptr = tomoyo_profile_ptr[profile];
         if (ptr)
                 goto ok;
-        ptr = tomoyo_alloc_element(sizeof(*ptr));
-        if (!ptr)
+        ptr = kmalloc(sizeof(*ptr), GFP_KERNEL);
+        if (!tomoyo_memory_ok(ptr)) {
+                kfree(ptr);
                 goto ok;
+        }
         for (i = 0; i < TOMOYO_MAX_CONTROL_INDEX; i++)
                 ptr->value[i] = tomoyo_control_array[i].current_value;
         mb(); /* Avoid out-of-order execution. */
@@ -1120,6 +1122,7 @@ static int tomoyo_update_manager_entry(const char *manager,
         saved_manager = tomoyo_save_name(manager);
         if (!saved_manager)
                 return -ENOMEM;
+        new_entry = kmalloc(sizeof(*new_entry), GFP_KERNEL);
         mutex_lock(&tomoyo_policy_lock);
         list_for_each_entry_rcu(ptr, &tomoyo_policy_manager_list, list) {
                 if (ptr->manager != saved_manager)
@@ -1132,15 +1135,16 @@ static int tomoyo_update_manager_entry(const char *manager,
                 error = -ENOENT;
                 goto out;
         }
-        new_entry = tomoyo_alloc_element(sizeof(*new_entry));
-        if (!new_entry)
+        if (!tomoyo_memory_ok(new_entry))
                 goto out;
         new_entry->manager = saved_manager;
         new_entry->is_domain = is_domain;
         list_add_tail_rcu(&new_entry->list, &tomoyo_policy_manager_list);
+        new_entry = NULL;
         error = 0;
  out:
         mutex_unlock(&tomoyo_policy_lock);
+        kfree(new_entry);
         return error;
 }
 
@@ -2148,35 +2152,6 @@ static int tomoyo_close_control(struct file *file)
 }
 
 /**
- * tomoyo_alloc_acl_element - Allocate permanent memory for ACL entry.
- *
- * @acl_type:  Type of ACL entry.
- *
- * Returns pointer to the ACL entry on success, NULL otherwise.
- */
-void *tomoyo_alloc_acl_element(const u8 acl_type)
-{
-        int len;
-        struct tomoyo_acl_info *ptr;
-
-        switch (acl_type) {
-        case TOMOYO_TYPE_SINGLE_PATH_ACL:
-                len = sizeof(struct tomoyo_single_path_acl_record);
-                break;
-        case TOMOYO_TYPE_DOUBLE_PATH_ACL:
-                len = sizeof(struct tomoyo_double_path_acl_record);
-                break;
-        default:
-                return NULL;
-        }
-        ptr = tomoyo_alloc_element(len);
-        if (!ptr)
-                return NULL;
-        ptr->type = acl_type;
-        return ptr;
-}
-
-/**
  * tomoyo_open - open() for /sys/kernel/security/tomoyo/ interface.
  *
  * @inode: Pointer to "struct inode".
diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h
index 874abf8df43e..610a6a056828 100644
--- a/security/tomoyo/common.h
+++ b/security/tomoyo/common.h
@@ -376,8 +376,6 @@ struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
 /* Check mode for specified functionality. */
 unsigned int tomoyo_check_flags(const struct tomoyo_domain_info *domain,
                                 const u8 index);
-/* Allocate memory for structures. */
-void *tomoyo_alloc_acl_element(const u8 acl_type);
 /* Fill in "struct tomoyo_path_info" members. */
 void tomoyo_fill_path_info(struct tomoyo_path_info *ptr);
 /* Run policy loader when /sbin/init starts. */
diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index 7d0b0bc48201..a55a1cced58e 100644
--- a/security/tomoyo/domain.c
+++ b/security/tomoyo/domain.c
@@ -245,6 +245,7 @@ static int tomoyo_update_domain_initializer_entry(const char *domainname,
         saved_program = tomoyo_save_name(program);
         if (!saved_program)
                 return -ENOMEM;
+        new_entry = kmalloc(sizeof(*new_entry), GFP_KERNEL);
         mutex_lock(&tomoyo_policy_lock);
         list_for_each_entry_rcu(ptr, &tomoyo_domain_initializer_list, list) {
                 if (ptr->is_not != is_not ||
@@ -259,17 +260,18 @@ static int tomoyo_update_domain_initializer_entry(const char *domainname,
                 error = -ENOENT;
                 goto out;
         }
-        new_entry = tomoyo_alloc_element(sizeof(*new_entry));
-        if (!new_entry)
+        if (!tomoyo_memory_ok(new_entry))
                 goto out;
         new_entry->domainname = saved_domainname;
         new_entry->program = saved_program;
         new_entry->is_not = is_not;
         new_entry->is_last_name = is_last_name;
         list_add_tail_rcu(&new_entry->list, &tomoyo_domain_initializer_list);
+        new_entry = NULL;
         error = 0;
  out:
         mutex_unlock(&tomoyo_policy_lock);
+        kfree(new_entry);
         return error;
 }
 
@@ -461,6 +463,7 @@ static int tomoyo_update_domain_keeper_entry(const char *domainname,
         saved_domainname = tomoyo_save_name(domainname);
         if (!saved_domainname)
                 return -ENOMEM;
+        new_entry = kmalloc(sizeof(*new_entry), GFP_KERNEL);
         mutex_lock(&tomoyo_policy_lock);
         list_for_each_entry_rcu(ptr, &tomoyo_domain_keeper_list, list) {
                 if (ptr->is_not != is_not ||
@@ -475,17 +478,18 @@ static int tomoyo_update_domain_keeper_entry(const char *domainname,
                 error = -ENOENT;
                 goto out;
         }
-        new_entry = tomoyo_alloc_element(sizeof(*new_entry));
-        if (!new_entry)
+        if (!tomoyo_memory_ok(new_entry))
                 goto out;
         new_entry->domainname = saved_domainname;
         new_entry->program = saved_program;
         new_entry->is_not = is_not;
         new_entry->is_last_name = is_last_name;
         list_add_tail_rcu(&new_entry->list, &tomoyo_domain_keeper_list);
+        new_entry = NULL;
         error = 0;
  out:
         mutex_unlock(&tomoyo_policy_lock);
+        kfree(new_entry);
         return error;
 }
 
@@ -650,6 +654,7 @@ static int tomoyo_update_alias_entry(const char *original_name,
         saved_aliased_name = tomoyo_save_name(aliased_name);
         if (!saved_original_name || !saved_aliased_name)
                 return -ENOMEM;
+        new_entry = kmalloc(sizeof(*new_entry), GFP_KERNEL);
         mutex_lock(&tomoyo_policy_lock);
         list_for_each_entry_rcu(ptr, &tomoyo_alias_list, list) {
                 if (ptr->original_name != saved_original_name ||
@@ -663,15 +668,16 @@ static int tomoyo_update_alias_entry(const char *original_name,
                 error = -ENOENT;
                 goto out;
         }
-        new_entry = tomoyo_alloc_element(sizeof(*new_entry));
-        if (!new_entry)
+        if (!tomoyo_memory_ok(new_entry))
                 goto out;
         new_entry->original_name = saved_original_name;
         new_entry->aliased_name = saved_aliased_name;
         list_add_tail_rcu(&new_entry->list, &tomoyo_alias_list);
+        new_entry = NULL;
         error = 0;
  out:
         mutex_unlock(&tomoyo_policy_lock);
+        kfree(new_entry);
         return error;
 }
 
@@ -738,7 +744,7 @@ struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
                                                             domainname,
                                                             const u8 profile)
 {
-        struct tomoyo_domain_info *domain = NULL;
+        struct tomoyo_domain_info *domain;
         const struct tomoyo_path_info *saved_domainname;
 
         mutex_lock(&tomoyo_policy_lock);
@@ -750,43 +756,17 @@ struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
         saved_domainname = tomoyo_save_name(domainname);
         if (!saved_domainname)
                 goto out;
-        /* Can I reuse memory of deleted domain? */
-        list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
-                struct task_struct *p;
-                struct tomoyo_acl_info *ptr;
-                bool flag;
-                if (!domain->is_deleted ||
-                    domain->domainname != saved_domainname)
-                        continue;
-                flag = false;
-                read_lock(&tasklist_lock);
-                for_each_process(p) {
-                        if (tomoyo_real_domain(p) != domain)
-                                continue;
-                        flag = true;
-                        break;
-                }
-                read_unlock(&tasklist_lock);
-                if (flag)
-                        continue;
-                list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
-                        ptr->type |= TOMOYO_ACL_DELETED;
-                }
-                tomoyo_set_domain_flag(domain, true, domain->flags);
-                domain->profile = profile;
-                domain->quota_warned = false;
-                mb(); /* Avoid out-of-order execution. */
-                domain->is_deleted = false;
-                goto out;
-        }
-        /* No memory reusable. Create using new memory. */
-        domain = tomoyo_alloc_element(sizeof(*domain));
-        if (domain) {
+        domain = kmalloc(sizeof(*domain), GFP_KERNEL);
+        if (tomoyo_memory_ok(domain)) {
                 INIT_LIST_HEAD(&domain->acl_info_list);
                 domain->domainname = saved_domainname;
                 domain->profile = profile;
                 list_add_tail_rcu(&domain->list, &tomoyo_domain_list);
+        } else {
+                kfree(domain);
+                domain = NULL;
         }
+
  out:
         mutex_unlock(&tomoyo_policy_lock);
         return domain;
diff --git a/security/tomoyo/file.c b/security/tomoyo/file.c
index 5d1689d6e16c..075392c052b4 100644
--- a/security/tomoyo/file.c
+++ b/security/tomoyo/file.c
@@ -225,6 +225,7 @@ static int tomoyo_update_globally_readable_entry(const char *filename,
         saved_filename = tomoyo_save_name(filename);
         if (!saved_filename)
                 return -ENOMEM;
+        new_entry = kmalloc(sizeof(*new_entry), GFP_KERNEL);
         mutex_lock(&tomoyo_policy_lock);
         list_for_each_entry_rcu(ptr, &tomoyo_globally_readable_list, list) {
                 if (ptr->filename != saved_filename)
@@ -237,14 +238,15 @@ static int tomoyo_update_globally_readable_entry(const char *filename,
                 error = -ENOENT;
                 goto out;
         }
-        new_entry = tomoyo_alloc_element(sizeof(*new_entry));
-        if (!new_entry)
+        if (!tomoyo_memory_ok(new_entry))
                 goto out;
         new_entry->filename = saved_filename;
         list_add_tail_rcu(&new_entry->list, &tomoyo_globally_readable_list);
+        new_entry = NULL;
         error = 0;
  out:
         mutex_unlock(&tomoyo_policy_lock);
+        kfree(new_entry);
         return error;
 }
 
@@ -372,6 +374,7 @@ static int tomoyo_update_file_pattern_entry(const char *pattern,
         saved_pattern = tomoyo_save_name(pattern);
         if (!saved_pattern)
                 return -ENOMEM;
+        new_entry = kmalloc(sizeof(*new_entry), GFP_KERNEL);
         mutex_lock(&tomoyo_policy_lock);
         list_for_each_entry_rcu(ptr, &tomoyo_pattern_list, list) {
                 if (saved_pattern != ptr->pattern)
@@ -384,14 +387,15 @@ static int tomoyo_update_file_pattern_entry(const char *pattern,
                 error = -ENOENT;
                 goto out;
         }
-        new_entry = tomoyo_alloc_element(sizeof(*new_entry));
-        if (!new_entry)
+        if (!tomoyo_memory_ok(new_entry))
                 goto out;
         new_entry->pattern = saved_pattern;
         list_add_tail_rcu(&new_entry->list, &tomoyo_pattern_list);
+        new_entry = NULL;
         error = 0;
  out:
         mutex_unlock(&tomoyo_policy_lock);
+        kfree(new_entry);
         return error;
 }
 
@@ -523,6 +527,7 @@ static int tomoyo_update_no_rewrite_entry(const char *pattern,
         saved_pattern = tomoyo_save_name(pattern);
         if (!saved_pattern)
                 return -ENOMEM;
+        new_entry = kmalloc(sizeof(*new_entry), GFP_KERNEL);
         mutex_lock(&tomoyo_policy_lock);
         list_for_each_entry_rcu(ptr, &tomoyo_no_rewrite_list, list) {
                 if (ptr->pattern != saved_pattern)
@@ -535,14 +540,15 @@ static int tomoyo_update_no_rewrite_entry(const char *pattern,
                 error = -ENOENT;
                 goto out;
         }
-        new_entry = tomoyo_alloc_element(sizeof(*new_entry));
-        if (!new_entry)
+        if (!tomoyo_memory_ok(new_entry))
                 goto out;
         new_entry->pattern = saved_pattern;
         list_add_tail_rcu(&new_entry->list, &tomoyo_no_rewrite_list);
+        new_entry = NULL;
         error = 0;
  out:
         mutex_unlock(&tomoyo_policy_lock);
+        kfree(new_entry);
         return error;
 }
 
@@ -901,9 +907,13 @@ static int tomoyo_update_single_path_acl(const u8 type, const char *filename,
                 goto out;
         }
         /* Not found. Append it to the tail. */
-        acl = tomoyo_alloc_acl_element(TOMOYO_TYPE_SINGLE_PATH_ACL);
-        if (!acl)
+        acl = kmalloc(sizeof(*acl), GFP_KERNEL);
+        if (!tomoyo_memory_ok(acl)) {
+                kfree(acl);
+                acl = NULL;
                 goto out;
+        }
+        acl->head.type = TOMOYO_TYPE_SINGLE_PATH_ACL;
         if (perm <= 0xFFFF)
                 acl->perm = perm;
         else
@@ -995,9 +1005,13 @@ static int tomoyo_update_double_path_acl(const u8 type, const char *filename1,
                 goto out;
         }
         /* Not found. Append it to the tail. */
-        acl = tomoyo_alloc_acl_element(TOMOYO_TYPE_DOUBLE_PATH_ACL);
-        if (!acl)
+        acl = kmalloc(sizeof(*acl), GFP_KERNEL);
+        if (!tomoyo_memory_ok(acl)) {
+                kfree(acl);
+                acl = NULL;
                 goto out;
+        }
+        acl->head.type = TOMOYO_TYPE_DOUBLE_PATH_ACL;
         acl->perm = perm;
         acl->filename1 = saved_filename1;
         acl->filename2 = saved_filename2;
diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c
index 9105e5e29da9..54226d5be493 100644
--- a/security/tomoyo/realpath.c
+++ b/security/tomoyo/realpath.c
@@ -212,57 +212,32 @@ static unsigned int tomoyo_allocated_memory_for_elements;
 static unsigned int tomoyo_quota_for_elements;
 
 /**
- * tomoyo_alloc_element - Allocate permanent memory for structures.
+ * tomoyo_memory_ok - Check memory quota.
  *
- * @size: Size in bytes.
+ * @ptr: Pointer to allocated memory.
  *
- * Returns pointer to allocated memory on success, NULL otherwise.
+ * Returns true on success, false otherwise.
  *
- * Memory has to be zeroed.
- * The RAM is chunked, so NEVER try to kfree() the returned pointer.
+ * Caller holds tomoyo_policy_lock.
+ * Memory pointed by @ptr will be zeroed on success.
  */
-void *tomoyo_alloc_element(const unsigned int size)
+bool tomoyo_memory_ok(void *ptr)
 {
-        static char *buf;
-        static DEFINE_MUTEX(lock);
-        static unsigned int buf_used_len = PATH_MAX;
-        char *ptr = NULL;
-        /*Assumes sizeof(void *) >= sizeof(long) is true. */
-        const unsigned int word_aligned_size
-                = roundup(size, max(sizeof(void *), sizeof(long)));
-        if (word_aligned_size > PATH_MAX)
-                return NULL;
-        mutex_lock(&lock);
-        if (buf_used_len + word_aligned_size > PATH_MAX) {
-                if (!tomoyo_quota_for_elements ||
-                    tomoyo_allocated_memory_for_elements
-                    + PATH_MAX <= tomoyo_quota_for_elements)
-                        ptr = kzalloc(PATH_MAX, GFP_KERNEL);
-                if (!ptr) {
-                        printk(KERN_WARNING "ERROR: Out of memory "
-                               "for tomoyo_alloc_element().\n");
-                        if (!tomoyo_policy_loaded)
-                                panic("MAC Initialization failed.\n");
-                } else {
-                        buf = ptr;
-                        tomoyo_allocated_memory_for_elements += PATH_MAX;
-                        buf_used_len = word_aligned_size;
-                        ptr = buf;
-                }
-        } else if (word_aligned_size) {
-                int i;
-                ptr = buf + buf_used_len;
-                buf_used_len += word_aligned_size;
-                for (i = 0; i < word_aligned_size; i++) {
-                        if (!ptr[i])
-                                continue;
-                        printk(KERN_ERR "WARNING: Reserved memory was tainted! "
-                               "The system might go wrong.\n");
-                        ptr[i] = '\0';
-                }
+        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;
+                memset(ptr, 0, allocated_len);
         }
-        mutex_unlock(&lock);
-        return ptr;
+        return result;
 }
 
 /* Memory allocated for string data in bytes. */
diff --git a/security/tomoyo/realpath.h b/security/tomoyo/realpath.h
index 78217a37960b..47b4f59dad6f 100644
--- a/security/tomoyo/realpath.h
+++ b/security/tomoyo/realpath.h
@@ -36,11 +36,8 @@ char *tomoyo_realpath_nofollow(const char *pathname);
 /* Same with tomoyo_realpath() except that the pathname is already solved. */
 char *tomoyo_realpath_from_path(struct path *path);
 
-/*
- * Allocate memory for ACL entry.
- * The RAM is chunked, so NEVER try to kfree() the returned pointer.
- */
-void *tomoyo_alloc_element(const unsigned int size);
+/* Check memory quota. */
+bool tomoyo_memory_ok(void *ptr);
 
 /*
  * Keep the given name on the RAM.