1 files changed, 82 insertions, 37 deletions

diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index ddfb9cccf468..fdd1f4b8c448 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -28,7 +28,13 @@ static const char *tomoyo_mode_2[4] = {
         "disabled", "enabled", "enabled", "enabled"
 };
 
-/* Table for profile. */
+/*
+ * tomoyo_control_array is a static data which contains
+ *
+ *  (1) functionality name used by /sys/kernel/security/tomoyo/profile .
+ *  (2) initial values for "struct tomoyo_profile".
+ *  (3) max values for "struct tomoyo_profile".
+ */
 static struct {
         const char *keyword;
         unsigned int current_value;
@@ -39,7 +45,13 @@ static struct {
         [TOMOYO_VERBOSE]          = { "TOMOYO_VERBOSE",      1,       1 },
 };
 
-/* Profile table. Memory is allocated as needed. */
+/*
+ * tomoyo_profile is a structure which is used for holding the mode of access
+ * controls. TOMOYO has 4 modes: disabled, learning, permissive, enforcing.
+ * An administrator can define up to 256 profiles.
+ * The ->profile of "struct tomoyo_domain_info" is used for remembering
+ * the profile's number (0 - 255) assigned to that domain.
+ */
 static struct tomoyo_profile {
         unsigned int value[TOMOYO_MAX_CONTROL_INDEX];
         const struct tomoyo_path_info *comment;
@@ -428,7 +440,6 @@ void tomoyo_fill_path_info(struct tomoyo_path_info *ptr)
         const char *name = ptr->name;
         const int len = strlen(name);
 
-        ptr->total_len = len;
         ptr->const_len = tomoyo_const_part_length(name);
         ptr->is_dir = len && (name[len - 1] == '/');
         ptr->is_patterned = (ptr->const_len < len);
@@ -866,7 +877,6 @@ static struct tomoyo_profile *tomoyo_find_or_assign_new_profile(const unsigned
 
         if (profile >= TOMOYO_MAX_PROFILES)
                 return NULL;
-        /***** EXCLUSIVE SECTION START *****/
         mutex_lock(&lock);
         ptr = tomoyo_profile_ptr[profile];
         if (ptr)
@@ -880,7 +890,6 @@ static struct tomoyo_profile *tomoyo_find_or_assign_new_profile(const unsigned
         tomoyo_profile_ptr[profile] = ptr;
  ok:
         mutex_unlock(&lock);
-        /***** EXCLUSIVE SECTION END *****/
         return ptr;
 }
 
@@ -1009,7 +1018,19 @@ static int tomoyo_read_profile(struct tomoyo_io_buffer *head)
         return 0;
 }
 
-/* Structure for policy manager. */
+/*
+ * tomoyo_policy_manager_entry is a structure which is used for holding list of
+ * domainnames or programs which are permitted to modify configuration via
+ * /sys/kernel/security/tomoyo/ interface.
+ * It has following fields.
+ *
+ *  (1) "list" which is linked to tomoyo_policy_manager_list .
+ *  (2) "manager" is a domainname or a program's pathname.
+ *  (3) "is_domain" is a bool which is true if "manager" is a domainname, false
+ *      otherwise.
+ *  (4) "is_deleted" is a bool which is true if marked as deleted, false
+ *      otherwise.
+ */
 struct tomoyo_policy_manager_entry {
         struct list_head list;
         /* A path to program or a domainname. */
@@ -1018,7 +1039,36 @@ struct tomoyo_policy_manager_entry {
         bool is_deleted; /* True if this entry is deleted. */
 };
 
-/* The list for "struct tomoyo_policy_manager_entry". */
+/*
+ * tomoyo_policy_manager_list is used for holding list of domainnames or
+ * programs which are permitted to modify configuration via
+ * /sys/kernel/security/tomoyo/ interface.
+ *
+ * An entry is added by
+ *
+ * # echo '<kernel> /sbin/mingetty /bin/login /bin/bash' > \
+ *                                        /sys/kernel/security/tomoyo/manager
+ *  (if you want to specify by a domainname)
+ *
+ *  or
+ *
+ * # echo '/usr/lib/ccs/editpolicy' > /sys/kernel/security/tomoyo/manager
+ *  (if you want to specify by a program's location)
+ *
+ * and is deleted by
+ *
+ * # echo 'delete <kernel> /sbin/mingetty /bin/login /bin/bash' > \
+ *                                        /sys/kernel/security/tomoyo/manager
+ *
+ *  or
+ *
+ * # echo 'delete /usr/lib/ccs/editpolicy' > \
+ *                                        /sys/kernel/security/tomoyo/manager
+ *
+ * and all entries are retrieved by
+ *
+ * # cat /sys/kernel/security/tomoyo/manager
+ */
 static LIST_HEAD(tomoyo_policy_manager_list);
 static DECLARE_RWSEM(tomoyo_policy_manager_list_lock);
 
@@ -1050,7 +1100,6 @@ static int tomoyo_update_manager_entry(const char *manager,
         saved_manager = tomoyo_save_name(manager);
         if (!saved_manager)
                 return -ENOMEM;
-        /***** EXCLUSIVE SECTION START *****/
         down_write(&tomoyo_policy_manager_list_lock);
         list_for_each_entry(ptr, &tomoyo_policy_manager_list, list) {
                 if (ptr->manager != saved_manager)
@@ -1072,7 +1121,6 @@ static int tomoyo_update_manager_entry(const char *manager,
         error = 0;
  out:
         up_write(&tomoyo_policy_manager_list_lock);
-        /***** EXCLUSIVE SECTION END *****/
         return error;
 }
 
@@ -1117,10 +1165,9 @@ static int tomoyo_read_manager_policy(struct tomoyo_io_buffer *head)
                                  list);
                 if (ptr->is_deleted)
                         continue;
-                if (!tomoyo_io_printf(head, "%s\n", ptr->manager->name)) {
-                        done = false;
+                done = tomoyo_io_printf(head, "%s\n", ptr->manager->name);
+                if (!done)
                         break;
-                }
         }
         up_read(&tomoyo_policy_manager_list_lock);
         head->read_eof = done;
@@ -1197,13 +1244,11 @@ static bool tomoyo_is_select_one(struct tomoyo_io_buffer *head,
 
         if (sscanf(data, "pid=%u", &pid) == 1) {
                 struct task_struct *p;
-                /***** CRITICAL SECTION START *****/
                 read_lock(&tasklist_lock);
                 p = find_task_by_vpid(pid);
                 if (p)
                         domain = tomoyo_real_domain(p);
                 read_unlock(&tasklist_lock);
-                /***** CRITICAL SECTION END *****/
         } else if (!strncmp(data, "domain=", 7)) {
                 if (tomoyo_is_domain_def(data + 7)) {
                         down_read(&tomoyo_domain_list_lock);
@@ -1447,15 +1492,14 @@ static int tomoyo_read_domain_policy(struct tomoyo_io_buffer *head)
                     TOMOYO_DOMAIN_FLAGS_IGNORE_GLOBAL_ALLOW_READ)
                         ignore_global_allow_read
                                 = TOMOYO_KEYWORD_IGNORE_GLOBAL_ALLOW_READ "\n";
-                if (!tomoyo_io_printf(head,
-                                      "%s\n" TOMOYO_KEYWORD_USE_PROFILE "%u\n"
-                                      "%s%s%s\n", domain->domainname->name,
-                                      domain->profile, quota_exceeded,
-                                      transition_failed,
-                                      ignore_global_allow_read)) {
-                        done = false;
+                done = tomoyo_io_printf(head, "%s\n" TOMOYO_KEYWORD_USE_PROFILE
+                                        "%u\n%s%s%s\n",
+                                        domain->domainname->name,
+                                        domain->profile, quota_exceeded,
+                                        transition_failed,
+                                        ignore_global_allow_read);
+                if (!done)
                         break;
-                }
                 head->read_step = 2;
 acl_loop:
                 if (head->read_step == 3)
@@ -1463,24 +1507,22 @@ acl_loop:
                 /* Print ACL entries in the domain. */
                 down_read(&tomoyo_domain_acl_info_list_lock);
                 list_for_each_cookie(apos, head->read_var2,
-                                      &domain->acl_info_list) {
+                                     &domain->acl_info_list) {
                         struct tomoyo_acl_info *ptr
                                 = list_entry(apos, struct tomoyo_acl_info,
-                                              list);
-                        if (!tomoyo_print_entry(head, ptr)) {
-                                done = false;
+                                             list);
+                        done = tomoyo_print_entry(head, ptr);
+                        if (!done)
                                 break;
-                        }
                 }
                 up_read(&tomoyo_domain_acl_info_list_lock);
                 if (!done)
                         break;
                 head->read_step = 3;
 tail_mark:
-                if (!tomoyo_io_printf(head, "\n")) {
-                        done = false;
+                done = tomoyo_io_printf(head, "\n");
+                if (!done)
                         break;
-                }
                 head->read_step = 1;
                 if (head->read_single_domain)
                         break;
@@ -1550,11 +1592,10 @@ static int tomoyo_read_domain_profile(struct tomoyo_io_buffer *head)
                 domain = list_entry(pos, struct tomoyo_domain_info, list);
                 if (domain->is_deleted)
                         continue;
-                if (!tomoyo_io_printf(head, "%u %s\n", domain->profile,
-                                      domain->domainname->name)) {
-                        done = false;
+                done = tomoyo_io_printf(head, "%u %s\n", domain->profile,
+                                        domain->domainname->name);
+                if (!done)
                         break;
-                }
         }
         up_read(&tomoyo_domain_list_lock);
         head->read_eof = done;
@@ -1594,13 +1635,11 @@ static int tomoyo_read_pid(struct tomoyo_io_buffer *head)
                 const int pid = head->read_step;
                 struct task_struct *p;
                 struct tomoyo_domain_info *domain = NULL;
-                /***** CRITICAL SECTION START *****/
                 read_lock(&tasklist_lock);
                 p = find_task_by_vpid(pid);
                 if (p)
                         domain = tomoyo_real_domain(p);
                 read_unlock(&tasklist_lock);
-                /***** CRITICAL SECTION END *****/
                 if (domain)
                         tomoyo_io_printf(head, "%d %u %s", pid, domain->profile,
                                          domain->domainname->name);
@@ -2138,7 +2177,13 @@ static ssize_t tomoyo_write(struct file *file, const char __user *buf,
         return tomoyo_write_control(file, buf, count);
 }
 
-/* Operations for /sys/kernel/security/tomoyo/ interface. */
+/*
+ * tomoyo_operations is a "struct file_operations" which is used for handling
+ * /sys/kernel/security/tomoyo/ interface.
+ *
+ * Some files under /sys/kernel/security/tomoyo/ directory accept open(O_RDWR).
+ * See tomoyo_io_buffer for internals.
+ */
 static const struct file_operations tomoyo_operations = {
         .open    = tomoyo_open,
         .release = tomoyo_release,